Solid Adsorbents for Low-Temperature CO2 Capture with Low-Energy Penalties Leading to More Effective Integrated Solutions for Power Generation and Industrial Processes

W2025430917 · 수집 2026-10-04 18:12:19

T11362 Membrane Separation and Gas Transport

CoT 라벨링

라벨링 전

PDF 파일

자동 다운로드한 PDF PDF 보기

기본 정보

DOI 제목 발행년도 저널 URL 페이지 열기 PDF URL PDF 열기 발행기관 피인용수 라이선스

추가 정보 초록

CO2 capture represents the key technology for CO2 reduction within the framework of CO2 capture, utilization, and storage (CCUS). In fact, the implementation of CO2 capture extends far beyond CCUS since it will link the CO2 emission and recycling sectors, and when renewables are used to provide necessary energy input, CO2 capture would enable a profitable zero- or even negative-emitting and integrated energy-chemical solution. To this end, highly efficient CO2 capture technologies are needed, and adsorption using solid adsorbents has the potential to be one of the ideal options. Currently, the greatest challenge in this area is the development of adsorbents with high performance that balances a range of optimization-needed factors, those including costs, efficiency, and engineering feasibility. In this review, recent advances on the development of carbon-based and immobilized organic amines-based CO2 adsorbents are summarized, the selection of these particular categories of materials is because they are among the most developed low temperature (<100 oC) CO2 adsorbents up to date, which showed important potential for practical deployment at pilot-scale in the near future. Preparation protocols, adsorption behaviors as well as pros and cons of each type of the adsorbents are presented, it was concluded that encouraging results have been achieved already, however, the development of more effective adsorbents for CO2 capture remains challenging and further innovations in the design and synthesis of adsorbents are needed.

본문

### ENERGY RESEARCH doi: 10.3389/fenrg.2015.00009

# Solid adsorbents for low-temperature CO2 capture with low-energy penalties leading to more effective integrated solutions for power generation and industrial processes

_[Nannan Sun](http://www.frontiersin.org/people/u/190950)_ _1,2_ _, ZhiyongTang_ _1_ _[,Wei Wei](http://www.frontiersin.org/people/u/195455)_ _1_ _[, Colin Edward Snape](http://www.frontiersin.org/people/u/194748)_ _2_ _[andYuhan Sun](http://www.frontiersin.org/people/u/167909)_ _1_ _*_

_1_ _Chinese Academy of Sciences Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of_
_Sciences, Shanghai, China_

_2_ _Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, UK_

_Edited by:_
_Peter Styring, The University of_
_Sheffield, UK_

_Reviewed by:_
_Paul S. Fennell, Imperial College_
_London, UK_
_Peng Li, Northwestern University,_
_USA_

_*Correspondence:_
_Yuhan Sun, Shanghai Advanced_

_Research Institute, Chinese Academy_
_of Sciences, 100 Haike Road,_
_Zhangjiang, Pudong, Shanghai_
_201203, China_
_[e-mail: sunyh@sari.ac.cn](mailto:sunyh@sari.ac.cn)_

CO2 capture represents the key technology for CO2 reduction within the framework of
CO2 capture, utilization, and storage (CCUS). In fact, the implementation of CO2 capture
extends far beyond CCUS since it will link the CO2 emission and recycling sectors, and
when renewables are used to provide necessary energy input, CO2 capture would enable
a profitable zero- or even negative-emitting and integrated energy–chemical solution. To
this end, highly efficient CO2 capture technologies are needed, and adsorption using solid
adsorbents has the potential to be one of the ideal options. Currently, the greatest challenge
in this area is the development of adsorbents with high performance that balances a range
of optimization-needed factors, those including costs, efficiency, and engineering feasibility. In this review, recent advances on the development of carbon-based and immobilized
organic amines-based CO2 adsorbents are summarized, the selection of these particular
categories of materials is because they are among the most developed low-temperature
( _<_ 100°C) CO2 adsorbents up to date, which showed important potential for practical deployment at pilot-scale in the near future. Preparation protocols, adsorption behaviors as well
as pros and cons of each type of the adsorbents are presented, it was concluded that
encouraging results have been achieved already, however, the development of more effective adsorbents for CO2 capture remains challenging and further innovations in the design
and synthesis of adsorbents are needed.

Keywords: CCUS, CO2 capture, adsorption, energy, material science

INTRODUCTION
CO2 CAPTURE AND AN INTEGRATED ENERGY–CHEMICAL SOLUTION
The atmospheric CO2 concentration now exceeds 400 ppm
(CO2Now.org, 2014), and its continuous increase is believed to
be the major factor leading to global warming and climatic change
(Crowley, 2000; Held and Soden, 2000; Patz et al., 2005). Kaya
et al. and Hoffert et al. have quantified net CO2 emissions in terms
of population, economic activity, and energy-related factors using
Eq. 1 (Kaya, 1995; Hoffert et al., 1998).

_C_ = _P_ × GDP

_E_

GDP ×

_P_ GDP × _C_ _E_

(1)

_C_ _E_

major strategies for CO2 sequestration (third and fourth term in
Eq. 1).

The complete decarbonization of energy is believed to be the
ultimate solution for the long-term sustainability, and thus over
the past decades, considerable researches have been devoted to
the development of low-carbon technologies covering nearly all
forms of energy (Song, 2006; Li and Fan, 2008; Kumar et al.,
2009; Panwar et al., 2011; Swain et al., 2011; Vasireddy et al., 2011;
Chu and Majumdar, 2012; Shi et al., 2013; Sangeeta et al., 2014).
Novel concepts and ideas for fossil, bio-, and renewable energies
have emerged as depicted in Figure 1 . Indeed, for the continued
using of fossil energy and fully decarbonized electricity supply,
CO2 capture, utilization, and storage (CCUS) has been recognized as one of the key technologies that needs to be demonstrated
and commercialized (Mikkelsen et al., 2010; Boot-Handford et al.,
2014).
As the most energy- and cost-intensive phase of CCUS, it is
well-demonstrated that CO2 capture is of vital importance to
the technical and economical availability of the technology, and
many investigations have been carried out (MacDowell et al.,
2010; Markewitz et al., 2012). However, fewer researchers have
recognized that CO2 capture, when linked to CO2 utilization and
chemical production processes, will act as an enabling technology
for more effective integrated energy solutions, for example, as

where _C_ is the net CO2 emission, _P_ is population, GDP is the gross
domestic product that is used here as an indicator of economyrelated factor, and _E_ is energy production. Therefore, GDP/ _P_ is
the Per capita GDP, and _E_ /GDP can be regarded as the energy
intensity during production that is closely related to the efficiency
of energy utilization. The last term, _C_ / _E_, represents the carbon
intensity during energy production. As for the development of
the human society and life quality, it is improper to limit population and production, which means there is no solution to CO2
reduction from the first and second term in Eq. 1. On the other
hand, increase in the energy production/utilization efficiency and
control of the carbon footprint during energy processes are the

FIGURE 1 | Overall solutions for low-carbon energy and chemical production from fossil, biomass, and renewable sources .

FIGURE 2 | An integrated energy–chemical solution with CO2 capture .

those depicted in Figure 2 where all the energies needed for fuel
upgrading and chemical production are provided by renewables,
and CO2 capture represents a linker between the CO2 emitting and
recycling processes (red and green arrows in Figure 2, respectively;
Graves et al., 2011; Budzianowski, 2012; Siglinda and Centi, 2014).
Consequently, carbon is fully converted to fuels and/or chemicals in this integrated energy–chemical scenario so that near zero
emissions can be achieved. Furthermore, if CO2 is captured from
power plants running on biomass, then an integrated energy and
chemical production scenario with negative carbon emissions can
be achieved that would potentially be profitable when carbon tax
is applied.

Based on these future energy scenarios, it is obvious that CO2
capture is even more important to the integrated energy–chemical
solution as compared to CCUS. This is not to say that development of CCUS is unnecessary, but to emphasize that CO2 capture
may be involved in our combat toward climate change and energy
solution much longer than we currently recognize.

TECHNICAL OPTIONS FOR CO2 CAPTURE AND THE POTENTIAL OF
SOLID ADSORBENTS
Currently, the state-of-the-art technology for CO2 separation is
amine scrubbing. In this process, CO2 in a mixture gas is absorbed
by an aqueous solution of alkanolamine via the acid–base reaction,
and the amines can be regenerated by stripping with water vapor
at elevated temperatures, concentrated CO2 can be obtained after
water is condensed from the stripper vapor (Rochelle,2009). However, although amine scrubbing technology has been deployed in
a range of applications such as natural gas sweetening, it suffers
from a number of shortcomings such as high energy penalty, thermal/oxidative degradation of the solvents, and corrosion (Sunil
and Merched, 2014). Furthermore, when amine scrubbing is
applied, the overall energy penalty at power plants reduces efficiency typically by 10%, representing a reduction in electricity
generation of 25% for a modern supercritical coal power plant. On
the other hand, some emerging technologies, such as membranes,
are still in their infancy, therefore, more energy-efficient processes

are needed to be developed for CO2 capture, where adsorption is
one such alternative (Choi et al., 2009; Wang et al., 2011a).

The greatest challenge for adsorption is the development of
appropriate materials that can be effectively used under processing conditions (Choi et al., 2009; Bollini et al., 2011; Jones, 2011;
Sayari et al., 2011; Wang et al., 2011a,b). In many papers, adsorption capacity is the only criterion used to evaluate adsorbents,
for practical CO2 capture applications however, there are more
requirements. This is illustrated in Figure 3, where _process_ _cost_,
_process efficiency_, and _engineering feasibility_ are represented as the
corners of a triangle( _elements_,hereafter),and _factors_ (circles inside
the triangle) that determine the quality of an adsorbents can be
located in the triangle according to their influence on each of the
_elements_ .Forexample,the _factor_ of adsorption/desorptionkinetics
( _factor_ _6_ in Figure 3 ) is located at the bottom left of the triangle since adsorbents with fast kinetics can increase the efficiency
of a process and lowering the related costs by accelerating the
adsorption–desorption cycles. Meanwhile, faster cycling requires
better designed and integrated adsorption/desorption sub-units,
leading to further difficulties in process engineering and limitations in adsorbents selection. The comprehensive requirements
for CO2 adsorbents are also discussed in a recent review by Sayari
et al. (2011). In fact, it is arbitrary to gain any quantitative conclusions from Figure 3 as the influence of the different _factors_ on
the three key _elements_ may vary according to different CO2 capture environments, but it is obvious that development of suitable
materials for CO2 capture is indeed the key challenge.

FIGURE 3 | Features of solid CO2 adsorbents for industrial applications .

AIMS AND SCOPE OF THIS REVIEW
In this review, recent advances on researches of solid adsorbents
for CO2 capture is summarized,readers who are interested in other
CO2 capture technologies such as absorption, oxy-fuel, and chemical looping are directed to references (Bara et al., 2010; Blamey
et al., 2010; Karadas et al., 2010; Toftegaard et al., 2010; Du et al.,
2012; Zhang et al., 2012; Sunil and Merched, 2014). We will focus
on the low-temperature adsorbents because they can (i) potentially match the requirements in Figure 3 and (ii) be suitable
for using in the integrated energy–chemical solutions ( Figure 2 ).
Readers who are interested in mid-high-temperature CO2 adsorbents (which are very important materials for CO2 treatment as
well) are directed to references (Choi et al., 2009; Wang et al.,
2011a,b; Donat et al., 2012; Ridha et al., 2013; Zhao et al., 2013,
2014). At the same time, some of the emerging adsorbents such as
metal organic frameworks (MOFs), covalent organic frameworks
(COFs) where material cannot yet be prepared at large-scale for
the moment will not be covered. Readers who are interested in
these adsorbents are directed to several excellent reviews published recently (Choi et al., 2009; Wang et al., 2011a,b; Dawson
et al., 2012; Sumida et al., 2012).

CARBON
GENERAL INFORMATION
Carbon-based materials such as activated carbons (ACs), carbon nano-tubes (CNTs) have been used in gas separation for
a long time (Bradley, 2011; Ren et al., 2011; Ma et al., 2013;

Sevilla and Mokaya, 2014), and therefore, it is not surprising that
various carbons are prepared and tested as adsorbents for CO2
capture. Basically, carbon-based materials can be prepared by
high-temperature treatment of carbon-containing substance in an
inert atmosphere, ( _carbonization_, pre-treatments may be applied
before carbonization in some cases), the obtained carbons can be
further treated by _activation_, where the carbons are partially gasified by reaction with an activating agent (H2O steam, CO2, and
KOH),leading to enhanced porosity (microporosity,particularly).
_Functionalization_ of carbon materials may be performed at any
stage of their preparation to further modify the surface chemistry
toward desired tasks.

Activated carbons are characterized by their high surface areas
(typically _>_ 1000 m 2 /g) and low chemical activity, therefore, they
have been typically characterized as physical adsorbents (Sayari
et al., 2011; Wang et al., 2011a). Consequently, adsorption of
CO2 on carbon surface was believed to rely on the highly developed porous structure. It was reported that narrow microporosity
( _<_ 0.7 nm) is vitally important for CO2 adsorption at low pressures
(~1 bar), while at elevated pressures, larger pores are gradually
occupied, which means the adsorption occurs via a “pore-filling”
mechanism. Such a theory has been verified by some authors via
the linear relationship between the measured CO2 adsorption
capacities and the volumes of pores with different sizes as illustratedin Figures4 and 5 (Martinetal.,2011; Sunetal.,2013).More
recently, Hu et al. used a more sophisticated method (QuenchedSolid Density Functional Theory) to analyze the low-temperature
N2 adsorption data, by which high-resolution pore distributions
of a series of petroleum coke-derived carbons could be obtained.
Thisenabledconclusionstobedrawnthatatatmosphericpressure,
high-density CO2 filled the pores smaller than 1 nm,upon increasing pressure, larger pores are filled (up to about 4 nm at 10 bar; Hu
et al., 2011). Similar conclusions have also been achieved by using
Grand Canonical Monte Carlo simulation and Non-Local Density Functional Theory (NLDFT) (Martin-Martinez et al., 1995;
Cazorla-Amoros et al., 1996; Vishnyakov et al., 1999; Wei et al.,
2012).
Merits for carbon adsorbents include low cost, fast kinetics
(equilibrium adsorption can be achieved within less than 10 min),
ultra-high stability, easy-to-regenerate, hydrophobicity, and most
importantly, high adsorption capacities at elevated (partial) pressures, these features make them well suited to IGCC applications
(Choi et al., 2009; Shafeeyan et al., 2010). Their main disadvantage
currently is the low capacities at low (partial) pressures due to the
inert surface chemistry. To circumvent this issue, some attempts
with encouraging results have been published on the modification and/or activation of carbons to strengthen the surface affinity
toward CO2, by which the adsorption occurs to be more “chemical.”All these will be overviewed in the following sections, some of
the key parameters for carbon adsorbents reported in the literature
are summarized in Table 1 .

PURE CARBONS FROM DIFFERENT PRECURSORS
As mentioned above, carbon materials can be prepared by carbonization of almost all carbon-containing substances. In this
section, pure carbons without any hetero-atom modification for
CO2 capture that have been developed are summarized.

FIGURE 4 |The linearship between high-pressure CO2 adsorption
capacities (30°C, 40 bar) and porosity, reproduced from Sun et al.
(2013) .

FIGURE 5 |The linearship between CO2 adsorption capacities (25°C,
1 bar) and microporosity, reproduced from Wei et al. (2012) .

_Carbons from polymers_
Polymers have been frequently used as precursors for preparing
carbon-based CO2 adsorbents since the purity, porous structure,
macroscopic morphologies, and surface chemistries can be easily tuned by optimization and appropriate pre-treatment of the
polymer precursors. The most used polymer precursors were phenolic resins due to their relatively low costs (An et al., 2009; Martin
et al.,2011; de Souza et al.,2013; Garcia et al.,2013; Sun et al.,2013;
Wickramaratne and Jaroniec,2013). By varying the formaldehydeto-phenol ratio and catalysts during synthesis, resol and novolac
phenolic resins were prepared by Pevida et al., after carbonization
of the resulted resins and subsequent activation in a CO2 atmosphere, microporous carbons were obtained with CO2 adsorption
capacities of around 10.8 wt. % (25°C and 1 bar), which further
increased to 44.7 wt. % at a pressure of 25 bar on the best sample

Table 1 | Key parameters for carbon-based adsorbents .

Reference Precursor(s) Activation

agent

Adsorption

temperature (°C)

Adsorption (partial)

pressure (bar)

Adsorption

capacity (wt. %)

Martin et al. (2011) Phenolic resin CO2 25 1 10.8

25 44.7

Sun et al. (2013) Phenolic resin - 30 1 10.3

40 44.5

Hu et al. (2011) Petroleum coke KOH 25 1 15.2

10 38.3

Wei et al. (2012) Granular bamboo KOH 0 1 30.8

25 19.8

Wickramaratne and

Jaroniec (2013)

Phenolic resin KOH 0 1 39.1

23 20.2

de Souza et al. (2013) Phenolic resin KOH 0 1 30.8

25 19.4

An et al. (2009) Phenolic resin CO2 20 1 10.0

0 18.8

Ben et al. (2012) PAF-1 - 0 1 19.8

Zhang et al. (2013) PAF-1 - 22 1 18.2

Sevilla and Fuertes

(2011)

Biomass KOH 0 1 28.8

25 21.2

50 15.8

Wahby et al. (2010) Petroleum coke KOH 0 1 38.0

25 20.7

50 12.7

Silvestre-Albero et al.

(2011)

Petroleum residual KOH 25 1 20.8

50 240.0

Shao et al. (2011) Coal tar pitches KOH 25 18 90.9

Presser et al. (2011) Carbide KOH 0 1 30.4

CO2 29.9

Liu et al. (2011) Phenolic resin - 25 1 14.5

Sevilla et al. (2011) Polypyrrole KOH 0 1 25.9

25 16.9

50 9.4

Shen et al. (2011) Polyacrylonitrile KOH 25 1 19.8

Nandi et al. (2012) Polyacrylonitrile CO2 0 1 50.6

25 22.6

Chen et al. (2012) Melamine polymer - 25 1 14.1

Chandra et al. (2012) Polypyrrole KOH 25 1 18.9

Zhao et al. (2012a) _p_ -diaminobenzene, furfural alcohol KOH 25 0.2 7.7

1 19.8

8 46.3

Li et al. (2010) Ethylenediamine, carbon tetrachloride - 25 1 12.6

75 1 4.0

Xia et al. (2011) Acetonitrile - 0 1 30.4

25 19.3

Pevida et al. (2008) Melamine polymer - 25 1 9.9

75 3.8

Xia et al. (2012) Reduced-graphene-oxide/poly-thiophene KOH 25 1 19.8

Zhao et al. (2012b) _p_ -diaminobenzene KOH 25 0.1 7.1

1 17.8

Hao et al. (2011) Poly(benzoxazine-co-resol) - 0 1 14.5

25 11.2

Hao et al. (2010) Phenolic resin - 25 1 14.1

60 7.0

(Martin et al., 2011; Garcia et al., 2013). The adsorption capacities
of the phenolic resin-based adsorbents can be effectively improved
by KOH activation (20.2 wt. % at 23°C and 1 bar) or alternatively, by inducing a second carbon source during preparation
(ca. 13.0 wt. % at 25°C and 1 bar; An et al., 2009; de Souza et al.,
2013; Wickramaratne and Jaroniec, 2013).
In addition to phenolic resins, Qiu and co-workers carbonized
porous aromatic frameworks PAF-1 (Ben et al., 2009), and an allcarbon-scaffold microporous carbon was thus prepared, which
adsorbs 19.8 wt. % CO2 at 0°C and 1 bar, and the CO2/N2 adsorption selectivity is as high as 209 in a 15/85 CO2/N2 mixture as
calculated by the Ideal Adsorption Solution Theory (IAST) (Ben
et al., 2012). Similar to the strategy of Feng et al. (An et al.,
2009), adsorbents were prepared by embedding an extra carbon
source into the PAF-1 framework and, following carbonization,
the resulted sample gave a CO2 adsorption capacity of 18.2 wt. %
as compared to 15.5 wt. % over the bare PAF-1-derived carbon
owing to the introduction of ultra-narrow pores ( _<_ 0.8 nm) that
are very effective for CO2 adsorption at low (partial) pressure as
previously mentioned (Zhang et al., 2013).

_Carbons from biomass_
Biomass represents a cost-effective and widely available option
for the preparation of carbon materials (Mohan and Pittman,
2006; White et al., 2009; Kalyani and Anitha, 2013). For example, CO2 could be substantially adsorbed on olive stone or almond
shell (both are low-cost biomass residuals) derived carbon materials (Plaza et al., 2009). In Fuertes et al.’s work, hydrochar that
was obtained by hydrothermal treatment of selected biomass was
submitted to KOH activation, a high CO2 adsorption capacity of
21.2 wt. % was achieved at 25°C and 1 bar (Sevilla and Fuertes,
2011). Similarly, carbonization of bamboo followed by KOH activation led to ACs with almost the same CO2 adsorption capacity
at identical conditions (Wei et al., 2012).

_Carbons from pitches_
Carbons with superior adsorption capacity toward CO2 were prepared from KOH activation of petroleum pitch by Silvestre-Albero
et al.,the nature of the petroleum residue,the KOH/pitch ratio,the
mesophase content,and the preparation conditions are optimized,
the best sample achieved a CO2 adsorption capacity of 20.2 wt. %
at 25°C and 1 bar with excellent selectivity (~100% for CO2/CH4
separation and 14% for CO2/N2 separation), the performance was
claimed to be highly exceeding that for MOFs (Wahby et al., 2010;
Silvestre-Albero et al., 2011). Employing similar fabrication protocol (carbonization-KOH activation), Cao et al. prepared ACs
with high surface areas (~3000 m 2 /g) from coal tar pitches (Shao
et al., 2011), the samples showed relatively weak CO2 adsorption
at low pressures ( _<_ 10 wt. % at 25°C and 1 bar), surprisingly, with
the increasing of pressure,significant enhancing of adsorption was
observed with an extremely high CO2 uptake of nearly 90 wt. %
at 18 bar.

_Carbons from other precursors_
In contrast to the traditional precursors described above, some
alternative materials are emerging and have been tested by several researchers. For example, deep eutectic solvents composed of

resorcinol, 4-hexylresorcinol, and tetraethylammonium bromide
were used by Monte et al. for the preparation of carbons with good
capacities for CO2 adsorption (up to 10.0 wt. % at 25°C and 1 bar;
Patino et al., 2012). Gogotsi et al. treated titanium carbide powders in chlorine and hydrogen, after activation, one of the samples
exhibited a high CO2 adsorption capacity of 31.2 wt. % at 0°C
and 1 bar, a linearship between CO2 uptake and the pore volume
of narrow micropores was observed confirming their importance
to the adsorption of CO2 at low pressures (Presser et al., 2011).
More recently,Srinivas prepared a novel carbon materials by direct
carbonization of MOFs, thanks to the releasing of CO, CO2, and
gaseous Zn (which is formed by the reduction of ZnO during carbonization), a hierarchically porous structure with simultaneous
high surface area and pore volume can be obtained, and thus the
obtained samples adsorbed ~15.0 and 119.0 wt. % CO2 at 1 and
30 bar, respectively (27°C) (Srinivas et al., 2014).

HETERO-ATOM MODIFIED CARBONS
One of the challenges for the development of carbon-based CO2
adsorbents is to enhance their adsorption capacities at relatively
low pressures by strengthening their surface affinity toward the
CO2 molecule. The most studied strategy to address this issue is
modification of the carbon framework with hetero-atoms, such as
nitrogen, sulfur, and metallic atoms.

_Nitrogen-modified carbons_
Nitrogen-bearing functionalities are basic in nature, they interact more strongly with the acidic CO2 molecule as compared
with the neutral carbon framework. Therefore, introduction of
these groups into carbons has been investigated extensively as a
means to increase the CO2 adsorption capability. There are basically two approaches to involve nitrogen into the carbon frameworks, namely _post-synthesis treatment_ and _using nitrogen-bearing_
_precursors_ .

To introduce nitrogen by _post-synthesis_ _treatment_, thermal
treatment in ammonia gas is normally used since it decomposes
at elevated temperatures to nitrogen-bearing radicals such as NH2
and NH that are particularly active and can attack the carbon
framework leading to the modification of the carbon surface by
anchoring of nitrogen-bearing functionalities. By thermal treatment of commercially available ACs and biomass-derived carbons
in ammonia, it was confirmed that nitrogen functional groups
were successfully introduced into the carbon framework, and an
increase of CO2 adsorption was observed on the modified samples as compared with the pristine one (Przepiorski et al., 2004).
A similar effect of amination in enhancing the adsorption of CO2
has also been reported based on the modification of ordered
mesoporous carbons, which showed an adsorption capacity of
14.5 wt. % at 25°C and 1 bar (Liu et al., 2011). In fact, the amount
of nitrogen that can be introduced into the carbon framework by
post-synthesis treatment is low ( _<_ 5 wt. %), which led to limited
increases in CO2 uptakes, although a pre-oxidation step would
benefit the introduction of nitrogen (Shafeeyan et al., 2011), more
effective methodologies are yet to be developed.

_Direct carbonization of nitrogen-bearing precursors_ will lead to
the _in_ _situ_ retention of nitrogen as various functionalities in the
produced carbons. This has been demonstrated to be a more

promising means for the synthesis of carbon-based CO2 adsorbents as compared with the post-synthesis method in terms of
the amount of nitrogen that can be introduced into the carbon framework. Nitrogen-bearing polymers are excellent candidates as precursors for the preparation of CO2 adsorbents
owing to their wide availability. To such a purpose, polyacrylonitrile (PAN), polyacrylonitrile-block-poly( _n_ -butyl acrylate) (PANb-PBA),melamine modified phenolic resins,and polypyrrole have
been carbonized and activated by several authors. Evaluation of
these materials indicated high CO2 adsorption capacities up to
22.6 wt. % (25°C, 1 bar) with excellent kinetics, selectivity, and
regenerability (Drage et al., 2007; Sevilla et al., 2011; Shen et al.,
2011; Chen et al., 2012; Nandi et al., 2012; Zhong et al., 2012).
In Kim’s work, polypyrrole was combined with graphene sheets
by _in_ _situ_ polymerization of pyrrole in graphene oxide using
ammonium persulfate and subsequent reduction using hydrazine.
Such a combination offered a solution to the small surface area
and high cost of polypyrrole when used for CO2 capture, and
the resulted composite adsorbent possessed a high CO2 adsorption capacity of 18.9 wt. % at 25°C and 1 bar (Chandra et al.,
2012).
Hard templating represents an alternative route for the preparation of nitrogen-modified carbons by using wet chemistry and/or
chemical vapor deposition. Nitrogen-bearing precursors with a
“pre-defined porous structure” can be obtained by introducing

precursors into the matrix of the sacrificial template, which facilitates the efficacy of subsequent carbonization and activation.
Following this strategy, Han et al. developed porous carbon materials by using a tri-continuous mesoporous silica IBN-9 as a hard
template, the resulted samples after KOH activation exhibited very
high CO2 uptakes of 19.8 and 46.3 wt. % at 1 and 8 bar, respectively (25°C) (Zhao et al., 2012a). Similar results by using other
templates and carbon precursors are reported by a number of
groups (Pevida et al., 2008; Li et al., 2010; Xia et al., 2011; Wang
and Yang, 2012).

_Non-nitrogen atom modified carbons_
Park and co-workers employed a copper/nickel-electroplating
method to prepare copper oxide and nickel oxide-decorated carbons, it was found that the introduction of these metal oxides into
the carbon framework enhanced the adsorption of CO2 substantially due to the electron donating effect of copper and nickel
oxides. However, the adsorption capacity of these metal oxide
modified carbons are relatively low ( _<_ 10 wt. % at 25°C and 1 bar)
as compared with those of nitrogen-modified carbons (Jang and
Park, 2012; Kim et al., 2012).

Sulfur-doped carbons were prepared and evaluated for CO2
capture by Kim et al., the microporosity, surface area, and oxidized
sulfur content of the material were found to be the determining
factors for CO2 adsorption, with the highest CO2 uptake reported
being 19.8 wt. % at 25°C and 1° bar (Seema et al., 2014). Xia et al.
used zeolite EMC-2 as a hard template to fabricate sulfur modified carbons, a much lower adsorption capacity of 11.0 wt. % was
reported, most probably because activation was not carried out.
However, an ultra-high CO2 adsorption heat of 59 kJ/mol was
calculated at low CO2 coverage, this result indicates the promise
of the sulfur modified carbons to be used in low-pressure CO2

adsorption applications, and therefore further studies are needed
(Xia et al., 2012).

It is worth mentioning here that in a study by Han et al.,
extra-framework potassium cation was introduced into a nitrogen containing carbon material attempting to combine the strong
affinity from both basic sites,a high CO2 uptake at 25°C of 7.13 wt.
% at only 0.1 bar (more relevant to CO2 capture from flue gas)
was reached with excellent adsorption selectivity, which can be
related to the enhanced surface electrostatic interactions (Zhao
et al., 2012b).

CARBONS WITH ORDERED MACROSCOPIC MORPHOLOGIES
As illustrated in Figure 3, adsorbents that can be used in practical CO2 capture applications will have to be fabricated in certain physical forms, however, most of the reported carbon-based
CO2 adsorbents are powders with very low densities. Therefore,
they need to be further fabricated via pelletization or granulation process with the aid of binders or additives, which can often
lead to significant loss in their adsorption performance (Williams,
2001; Davis, 2002; Kadib et al., 2009; Lohe et al., 2009; Wen et al.,
2010; Hao et al., 2011). Correspondingly, it is of great promise
to directly prepare carbon adsorbents with ordered macroscopic
morphologies. To this end, using polymers as precursors, advantage of their ability to be easily fabricated to desired forms can
be taken, which can potentially be retained in the produced carbons. By carbonization of monolithic polymer precursors, Lu’s
group developed a nitrogen-modified carbon monolith with a
high mechanical strength, which exhibited CO2 adsorption capacities up to 14.5 wt. % at 25°C and 1 bar (Hao et al., 2010, 2011).
Uyama et al. dissolved PAN in a mixture of hot DMSO and H2O,
where cooling of the solution led to the phase separation and
resulted in a PAN monolith, and CO2 uptakes up to 22.6 wt. %
(25°C and 1° bar) were obtained after carbonization (Nandi et al.,
2012). Sun et al. developed a hydrothermal process to prepare
phenolic resin beads, after carbonization and subsequent modification, carbon beads with a diameter of ca. 0.7 mm were obtained.
Nitrogen-bearing functionalities can be introduced by either postsynthesis treatment of the beads or directly preparing melamine
modified resin beads, the samples exhibited CO2 uptakes of ca.
10.0 and 40.0 wt. % at 1 and 40 bar, respectively (30°C) (Sun et al.,
2013).
In summary,the development of carbon-based CO2 adsorbents
with high performance has been extensively investigated recently
with some encouraging results emerging. However, important
challenges remain unsolved such as enhancement of adsorption
capacities at low (partial) pressures by surface modification, lowering the cost of preparation by using biomass or wastes as
precursors, and so on.

IMMOBILIZED ORGANIC AMINES
GENERAL INFORMATION
Immobilization of organic amines into the pores of supporting
materials (normally SiO2) is one of the most studied adsorbent
systems for CO2 capture after Song and co-workers described the
concept of “molecular basket” (Xu et al., 2002, 2003). The basic
idea is dispersing organic amines, which are normally liquids of
high viscosity, in a porous support to best expose the basic amine

FIGURE 6 | Concept of “molecular basket,” reproduced from Ma et al. (2009) .

groups as adsorption sites, and thus the mass transfer difficulties
in pure amines can be circumvented ( Figure 6 ).

Thebasicadsorptionmechanismof thesematerialsisthechemical reaction between amine groups and CO2 that is similar to
aqueous amine scrubbing as shown by Eqs 2 and 3 (Sayari et al.,
2011).

2 _(_ RNH2 _)_ + CO2 ↔ RNHCO − 2 RNH 3 + (2)

RNH2 + CO2+H2O ↔ RNH + 3 HCO 3 − (3)

Primary and secondary amines react with CO2 following a
zwitterion mechanism where water or another amine group is
needed. Consequently, two amine groups are required to capture
one CO2 molecule in dry conditions (Eq. 2), while in the presence of water, bicarbonate can be formed to potentially double the
amine efficiency as indicated in Eq. 3. For tertiary amines, H2O
is necessary for CO2 adsorption via the formation of bicarbonate.
It should be noted that when taking the surface characteristics of
the immobilized amine adsorbents into consideration,the adsorption mechanism becomes more complicated. For example, amine
groups may react with the surface silanol groups leading to amine
efficiency lower than expected, and some of the initially formed
carbamic acid may remain unchanged due to the lack of amine
groups at close vicinity (Knofel et al., 2009; Bollini et al., 2011).
Even in the presence of H2O,the formation of carbamates is kinetically favored over bicarbonate although the latter is more stable.
The co-existence of the two competing reactions as well as the
potential mass transfer barriers from the surface to bulk amine
groups suggests that the CO2 adsorption by immobilized amines
will depend at least partially on contact time (Vaidya and Kenig,
2007; Serna-Guerrero et al., 2008; Wang et al., 2009).
According to Jones et al., the immobilized amine adsorbents
can be classified into three categories (Choi et al., 2009; Bollini
et al., 2011), namely (i) those prepared from physical deposition/combination of pre-synthesized amines onto SiO2 ( _Class 1_ ),
(ii) those materials with covalent bonds between the amines and
the SiO2 support ( _Class 2_ ), and (iii) those prepared by the _in situ_
polymerization of reactive amine monomers on and in the silica
support. Figure 7 reproduced from Bollini et al. (2011) illustrates the difference between these materials, and this section will
be organized according to this classification, key parameters for
immobilized amine adsorbents can be found in Tables 2 - 4 .

INTRODUCTION OF AMINE BY PHYSICAL DEPOSITION/COMBINATION
( _CLASS 1_ )
_Effect of support_
For the _Class_ _1_ immobilized amine adsorbents, pre-synthesized
organic amines are firstly dissolved in methanol or H2O, porous
SiO2 is then added and the formed slurry is stirred and dried to
remove the solvent,leading to the formation of amine–SiO2 hybrid
materials that amines are dispersed and filled into the pores of
SiO2. Therefore, the nature of support is of great importance to
the performance of the adsorbents by providing enough dispersing
spaces (Bollini et al., 2011).

The most widely investigated supports are ordered mesoporous SiO2 such as MCM-41 and SBA-15. It was reported that
upon loading of polyethylenimine (PEI) up to a certain level, the
porous structure of the original supports can be roughly reserved
although the surface area and pore volume decreased drastically.
Accordingly, the adsorption capacities of the resulted adsorbents
increasedwiththeloadingof PEIbeforeamaximumvalue(ca.14.0
and 18.0 wt. % for MCM-41 and SBA-15 supports, respectively at
75°C and 15/85% CO2/N2) is reached, after which over-loading of
the amines led to the decreasing of capacities as well as the adsorption kinetics. It is believedthat under extreme highamine loadings,
alltheporesarefilledandtheoutersurfaceof SiO2 willbecoatedby
the sticky amines,leading to limited accessibility of the bulk amine
molecules toward CO2 as illustrated in Figure 8 (Xu et al., 2003).
According to this model, the maximum amount of amines that
a SiO2 support can accommodate depends upon its pore volume,
and this hypothesis has been verified by experimental observations
that when the amount of the used amine is larger than that calculated according to the pore volume of the support and the density
of amine, the resultant adsorbent appears to be sticky and gel-like.
The high viscosity of the organic amines will also cause difficulties
in CO2 diffusion from the surface to the bulk amines, therefore a
two-stage adsorption kinetics was observed (a fast surface reaction
stage followed by a slower diffusion-controlling stage; Wang and
Song, 2012; Chen et al., 2013), and when adsorption temperature
was considered,it appears that rather than lower temperatures,the
highest capacities were typically obtained at 75°C so as to get rid
of the diffusion barrier.

The effectiveness of larger pore volumes in promoting the performance of the adsorbents was further evidenced by comparing
materials including MCM-41, MCM-48, SBA-15, SBA-16, KIT-6,

FIGURE 7 | Classification of immobilized amine adsorbents, reproduced from Bollini et al. (2011) .

and two hexagonal mesoporous silicas by Ahn et al. (Son et al.,
2008; Chen et al., 2010). Based on similar principle, commercialized fumed silica with large pore volumes ( _>_ 1 cm 3 /g) was also
tested to support PEI as CO2 adsorbents (Goeppert et al., 2010;
Zhang et al., 2014a,b). Recently, Giannelis and co-workers prepared a silica foam with ultra-large mesopores (1.46 cm 3 /g) so
that 80 wt. % PEI can be loaded, a high uptake of ca. 25.5 wt. %
(75°C and 1 bar) with fast adsorption kinetics was observed (Qi
et al., 2012). Similar capacities were achieved from the same group
by using mesoporous SiO2 capsules as a support (Qi et al., 2011),
the measured pore volume of the capsules was not high, however,
the hollow cores provided abundant space for the accommodation
of amines, leading to the exceptionally high adsorption capacities.

_Effect of amines_
Amine groups are the main adsorption sites and, therefore, the
type of the amine is another decisive factor in determining the
performance of the adsorbents. The most studied amines for

impregnating SiO2 support are tetraethylenepentamine (TEPA)
and PEIs with different molecular weights. Basically, owing to the
higher concentration of amine groups, larger amounts of primary
amine, and lower viscosity, higher capacities can be obtained by
using TEPA as compared with that of PEIs. However, the cyclic
stability of using TEPA is questionable due to its lower thermal
stability which led to amine loss during desorption at elevated
temperatures (Chen et al., 2009; Liu et al., 2010; Qi et al., 2011).
A similar theory can be applied to linear PEI as well. In contrast, in spite of the relatively lower adsorption capacity, PEIs
with higher molecular mass or a branched structure possessed
better thermal stability leading to a stable performance during
multi-adsorption/desorption cycles (Goeppert et al., 2010).

_Non-SiO2 support_
Comparable adsorption capacities have also been reported using
supports other than SiO2 (Wang et al., 2011c, 2012; Chen et al.,
2013). For example, low-cost carbons were used by Song et al.

Table 2 | Key parameters for _Class 1_ immobilized amine adsorbents .

Reference Support Amine Amine

loading (wt. %)

Adsorption

temperature (°C)

Adsorption (partial)

pressure (bar)

Adsorption

capacity (wt. %)

Xu et al. (2002, 2003) MCM-41 PEI 75 1 13.3

Chen et al. (2013) Resin PEI 75 0.15 13.0

Son et al. (2008) MCM-41 PEI 50 75 1 11.1

MCM-48 11.9

SBA-15 12.7

SBA-16 12.9

KIT-6 13.5

Chen et al. (2010) HMS PEI 60 75 1 18.4

Goeppert et al. (2010) Fumed SiO2 PEI 50 85 1 16.5

Qi et al. (2012) SiO2 foam PEI 80 75 1 25.5

Qi et al. (2011) SiO2 capsules PEI 83 75 0.1 19.6

TEPA 24.5

Wang et al. (2011c, 2012) Carbon PEI 50 75 1 13.5

Chaikittisilp et al. (2011a) γ-Alumina PEI 48 25 0.1 8.6

Table 3 | Key parameters for _Class 2_ immobilized amine adsorbents .

Reference Supporting

material

Grafted amine Adsorption

temperature (°C)

Adsorption (partial)

pressure (bar)

Adsorption

capacity (wt. %)

Serna-Guerrero et al.

(2010)

Pore-expended

MCM-41

Triamine-containing silane 25 0.05 9.0

Zelenak et al. (2008) MCM-41 3-Aminopropyltriethoxysilane 25 0.1 2.6

SBA-12 4.5

SBA-15 6.7

Zukal et al. (2009) ITQ-6 3-Aminopropyltrimethoxysilane 20 1 5.3

[3-(Methylamino)propyl]trimethoxysilane 4.2

[3-(Phenylamino)propyl]trimethoxysilane 2.2

Yang et al. (2012) MCM-22 3-Aminopropyltrimethoxysilane 25 1 6.7

MCM-36 5.3

ITQ-2 7.6

Table 4 | Key parameters for _Class 3_ immobilized amine adsorbents .

Reference Supporting

material

Organic precursors Adsorption

temperature (°C)

Adsorption (partial)

pressure (bar)

Adsorption

capacity (wt. %)

Liang et al. (2008) SBA-15 Melamine-based dendrimers 20 0.9 4.3

Liang et al. (2009) MCF Melamine-based dendrimers 20 0.9 3.9

Hicks et al. (2008) and

Drese et al. (2009)

SBA-15 Polymerized aziridine 75 0.1 8.8

to prepare the “molecular basket” adsorbents, and similar performance could be achieved as compared with the use of SBA-15
(Wang et al., 2011c). More importantly, when the volume-based
adsorption capacity was compared,those adsorbents using carbon
as support are even better (Wang et al., 2012). When synthesized
mesoporous alumina was used as a support for PEI, an enhanced
stability was observed under direct contact with steam, indicating
the feasibility of this support for the use in practical CO2 capture
applications (Chaikittisilp et al., 2011a).

INTRODUCTION OF AMINES BY GRAFTING (CLASS 2)
_Class 2_ immobilized amine adsorbents are those materials where
the amines are covalently bonded with the framework of a “supporting” material. They are typically prepared by surface grafting
based on the reaction between silanol groups on the surface of
SiO2 and the alkoxy groups in an aminosilane molecule.

A number of papers on _Class_ _2_ adsorbents are contributed
from Sayari’s group based on a pore-expended MCM-41 support, by grafting either a monoamine silane or triamine silane,

FIGURE 8 | Schematic diagram of PEI loaded in the mesoporous
molecular sieve of MCM-41 . (A) MCM-41 support; (B) low PEI loading;
(C) high PEI loading; (D) extremely high PEI loading, reproduced from Ma
et al. (2009).

the materials achieved CO2 capacities of 9.9 and 12.3 wt. % at
0.15 and 1 bar (25°C), respectively (Serna-Guerrero et al., 2008,
2010), and the materials can be used in a variety of environments (Belmabkhout et al., 2010). Other mesoporous silicas that
have been tested for the preparation of _Class 2_ adsorbents include
SBA-12, SBA-15, MCM-41, MCM-22, MCM-36, ITQ-2, ITQ-6,
and silica microspheres (Zelenak et al., 2008; Zukal et al., 2009;
Belmabkhout et al., 2010; Serna-Guerrero et al., 2010; Yang et al.,
2012). In contrast to _Class 1_ adsorbents, pore volumes of the supports for _Class_ _2_ are less important, and it was reported that
the effectiveness of these materials is influenced by the surface
area, pore diameter, pore connectivity, and most importantly, the
density of the surface silanol groups. This is expectable since
the maximum amount of aminosilane that can be grafted onto
SiO2 is determined by the amount of silanol groups existing on
the surface. A good demonstration of this relationship was presented by Yang et al., where the density of surface silanol groups
was tuned by using different template removal procedures, and
higher amine loadings can be achieved on the sample with more
silanol groups, resulting in a higher CO2 adsorption capacity and
selectivity (Wang and Yang, 2011).

It is necessary to mention here that, although several authors
have tried to enhance the grafting process by surface pre-treatment
(Harlick and Sayari, 2007; Zhao et al., 2010), the amount of
amine groups that can be introduced is still low as compared
with _Class_ _1_ adsorbents, leading to a substantially lower adsorption capacities which represents a major disadvantage of this
type of adsorbents. Merits of _Class_ _2_ adsorbents are obvious
such as the better-preserved textural properties of the supporting
framework, and more importantly, since the amines are covalently bonded with SiO2, their interactions with the support are
stronger, leading to a better stability as compared with _Class_ _1_
adsorbents.

CLASS 3
_Class_ _3_ immobilized amine adsorbents are characterized by the
_in situ_ polymerization of amines inside the pores of a silica material. Chaffee and co-workers used a stepwise growth strategy to
induce melamine-based dendrimers into the pores of SiO2, with
up to ca. 55 wt. % organic loadings could be achieved (fourth generation) leading to a substantially higher CO2 adsorption (4.0 wt.
% at 20°C and 90% CO2–10% Ar) as compared with the bare
support (Liang et al., 2008, 2009). Jones et al. reported a hyperbranched aminosilica (HAS) material for CO2 capture that was
synthesized by surface polymerization of aziridine initiated by
the silanols on the surface of SBA-15, the resultant adsorbent
exhibited a CO2 uptake of ca. 8.8 wt. % at 75°C in a wet 10%
CO2–90% Ar stream (Hicks et al., 2008; Drese et al., 2009). Later,
an investigation into the effect of support on the polymerization
of aziridine was carried out by the same group, but higher loadings could not be achieved by using pore-expanded SiO2 materials,
revealing that fabricating and controlling of the _in situ_ polymerization may be more complicated than expected (Drese et al.,
2012). Another example of the _Class_ _3_ adsorbents was synthesized by _in situ_ ring-opening polymerization of Z-protected lysine
_N_ -carboxyanhydride also by Jones’ group (Chaikittisilp et al.,
2011b).
Compared to _Class_ _1_ and _2_ adsorbents, it was claimed that
the _Class 3_ counterpart combined the advantages of the first two
types, namely increased amount of amine groups with covalent
bonding with the support, leading to a thermal stable adsorbents
with higher adsorption capacities (Hicks et al., 2008; Drese et al.,
2009, 2012; Liang et al., 2009). However, it seems that the actual
CO2 uptakes of _Class 3_ adsorbents are relatively low and,therefore,
further increasing the loading and/or the efficiency of the _in situ_
formed polymers should be addressed in future works.

DEGRADATION AND REJUVENATION OF IMMOBILIZED AMINE
ADSORBENTS
In most of the literatures, a gradual decreasing of adsorption
capacity of the immobilized amine adsorbents has been observed
owing to thermal and/or oxidative degradation (Heydari-Gorji
and Sayari, 2012). According to Sayari et al., formation of urealike compounds in dry capturing conditions caused irreversible
adsorption and finally leading to the deactivation of the adsorbents, the deactivated adsorbents can be fully recovered by treatment in steam-containing gases, and thus using wet CO2 as a
purge gas could provide opportunities to stabilized separation of
CO2 (Sayari and Belmabkhout, 2010; Sayari et al., 2012). More
recently, an in-depth investigation on the oxidative degradation
was reported by the same group, C = O and –CH = N– species
were conclusively identified by 1D and 2D NMR techniques
(Ahmadalinezhad and Sayari, 2014). Nevertheless, the mechanism
of amine degradation induced by different factors remains unclarified, and it is of particular importance to move to a further step,
namely how the deactivated amines can be rejuvenated, this is also
important to liquid amine scrubbing technologies since the degradation of solvents represents a major contributor to the entire costs
of the process.

To conclude, immobilization of organic amines results in a
series of adsorbents particularly suited to low (partial) pressure

Table 5 | Features of different adsorbents .

Adsorption behavior Preparation cost

Capacity Selectivity Kinetics Stability

Carbon High at elevated pressures,

low at elevated temperatures

Low–medium Fast ( _<_ 10 min to reach equilibrium

capacity)

High Slow at lower temperatures and when

amines are over loaded ( _>_ 20 min to

reach equilibrium capacity)

Good Low–medium

Medium–high

Capacity decreases at

prolonged adsorption–

desorption cycles

Immobilized

organic

amines

High at low pressures and

medium temperatures

(60–75°C)

CO2 capture due to the chemical adsorption that occurs, which
makes these materials the most suitable candidates for flue
gas treatment. Therefore, significant research efforts have been
devoted to this area. Currently, all three classes of adsorbents have
their own pros and cons,and further innovations and solutions are
still needed. Furthermore, the degradation of amines in practical
CO2 capture conditions was an universal observation for all the
three classes of adsorbents and understanding the involved mechanisms together with further treatments to mitigate degradation
are important.

CONCLUDING REMARKS AND OVERALL PERSPECTIVES
CO2 capture is an indispensable component for CCUS. Based on
our analysis however, the deployment of CO2 capture goes far
beyond CCUS and, in the future, it will connect the CO2 emission
and recycling sectors, leading to a profitable near carbon-zero or
even carbon-negative energy–chemical production and consumption networks. Thus, highly efficient CO2 capture processes, such
as using solid adsorbents and others (such as chemical looping,
oxy-fuel), are the enablers for integrated energy–chemical solutionswithhigherefficiencies.Inthisreview,therecentadvancesfor
adsorbents for low-temperature ( _<_ 100°C) CO2 capture have been
covered,namely carbon-based adsorbents and amine immobilized
adsorbents ( Table 5 ).

- Carbons are one of the most widely used adsorbents, which
also occurred to be one of the options for CO2 capture. Many
researches have been reported focusing on the investigations of
(i) selecting proper precursors for the preparation of carbons
and (ii) involving hetero-atoms to enhance the surface affinity
toward CO2. Encouraging results have emerged and these have
established the competence for scaling-up the production of
carbons for practical capture applications, and further works on
improving the capacity at low partial pressures and preparation
of carbons from low-cost precursors are necessary.

- Immobilized amines are characterized by their high capacities
at low (partial) pressures, this feature makes them a promising
candidate for CO2 capture from flue gas. Based on the preparation strategies, these adsorbents can be categorized into three
classes, namely (i) those prepared from the physical deposition/combination of pre-synthesized amine onto SiO2 ( _Class_
_1_ ), (ii) those materials with covalent bonds between the amines
and the SiO2 support ( _Class 2_ ), and (iii) those prepared by the
_insitu_ polymerizationof reactiveaminemonomersonandinthe

silica support. All the three classes of adsorbents have their own
pros and cons, further promotion of the capacities (for _Class 2_
and _3_ ), kinetics (for _Class 1_ ), and stabilities (for all three classes)
are needed. To this end, understanding the mechanisms of surface adsorption reaction and pathways for the thermal/oxidative
degradation is of vital importance.

Overall, the development of effective adsorbents for CO2 capture remains challenging despite the significant R&D activities
already happened. By taking practical conditions under different
circumstances for CO2 capture into consideration, further innovations in the design and synthesis of adsorbents are needed to
identify more efficient materials to balance the costs and engineering feasibilities of different capture processes. Further, the
importance of CO2 capture to enable future integrated energy
and chemical production processes needs to be re-assessed to drive
forward the development of solid adsorbent technology.

ACKNOWLEDGMENTS
The authors wish to acknowledge the financial support from the
National Natural Science Foundation of China (21203230).

REFERENCES
Ahmadalinezhad, A., and Sayari, A. (2014). Oxidative degradation of silica
supported polyethylenimine for CO2 adsorption: insights into the nature of
deactivated species. _Phys._ _Chem._ _Chem._ _Phys._ 16, 1529–1535. [doi:10.1039/](http://dx.doi.org/10.1039/c3cp53928h)
[c3cp53928h](http://dx.doi.org/10.1039/c3cp53928h)
An, H., Feng, B., and Su, S. (2009). CO2 capture capacities of activated carbon fibre
phenolic resin composites. _Carbon_ _N._ _Y._ 47, 2396–2405. [doi:10.1016/j.carbon.](http://dx.doi.org/10.1016/j.carbon.2009.04.029)
[2009.04.029](http://dx.doi.org/10.1016/j.carbon.2009.04.029)
Bara, J. E., Camper, D. E., Gin, D. L., and Noble, R. D. (2010). Room-temperature

ionic liquids and composite materials: platform technologies for CO2 capture.
_Acc. Chem. Res._ [43, 152–159. doi:10.1021/ar9001747](http://dx.doi.org/10.1021/ar9001747)
Belmabkhout, Y., Serna-Guerrero, R., and Sayari, A. (2010). Adsorption of CO2
containing gas mixtures over amine-bearing pore-expanded MCM-41 silica:
application for gas purification. _Ind. Eng. Chem. Res._ [49, 359–365. doi:10.1021/](http://dx.doi.org/10.1021/ie900837t)
[ie900837t](http://dx.doi.org/10.1021/ie900837t)
Ben, T., Li,Y. Q., Zhu, L. K., Zhang, D. L., Cao, D. P., Xiang, Z. H., et al. (2012). Selec
tive adsorption of carbon dioxide by carbonized porous aromatic framework
(PAF). _Energy Environ. Sci._ [5, 8370–8376. doi:10.1039/c2ee21935b](http://dx.doi.org/10.1039/c2ee21935b)
Ben, T., Ren, H., Ma, S., Cao, D., Lan, J., Jing, X., et al. (2009). Targeted synthesis of

a porous aromatic framework with high stability and exceptionally high surface
area. _Angew. Chem. Int. Ed._ [48, 9457–9460. doi:10.1002/anie.200904637](http://dx.doi.org/10.1002/anie.200904637)
Blamey, J., Anthony, E. J., Wang, J., and Fennell, P. S. (2010). The calcium loop
ing cycle for large-scale CO2 capture. _Prog._ _Energy_ _Combust._ _Sci._ 36, 260–279.
[doi:10.1016/j.pecs.2009.10.001](http://dx.doi.org/10.1016/j.pecs.2009.10.001)
Bollini, P., Didas, S. A., and Jones, C. W. (2011). Amine-oxide hybrid materials for

acid gas separations. _J. Mater. Chem._ [21, 15100–15120. doi:10.1039/c1jm12522b](http://dx.doi.org/10.1039/c1jm12522b)

Boot-Handford, M. E.,Abanades, J. C.,Anthony, E. J., Blunt, M. J., Brandani, S., Mac

Dowell, N., et al. (2014). Carbon capture and storage update. _Energy_ _Environ._
_Sci._ [7, 130–189. doi:10.1039/c3ee42350f](http://dx.doi.org/10.1039/c3ee42350f)
Bradley, R. H. (2011). Recent developments in the physical adsorption of toxic

organic vapours by activated carbons. _Adsorpt._ _Sci._ _Technol._ 29, 1–28. [doi:10.](http://dx.doi.org/10.1260/0263-6174.29.1.1)
[1260/0263-6174.29.1.1](http://dx.doi.org/10.1260/0263-6174.29.1.1)
Budzianowski, W. M. (2012). Negative carbon intensity of renewable energy tech
nologies involving biomass or carbon dioxide as inputs. _Renew. Sustain. Energ._
_Rev._ [16, 6507–6521. doi:10.1016/j.rser.2012.08.016](http://dx.doi.org/10.1016/j.rser.2012.08.016)
Cazorla-Amoros, D., Alcaniz-Monge, J., and Linares-Solano, A. (1996). Characteri
zation of activated carbon fibers by CO2 adsorption. _Langmuir_ 12, 2820–2824.
[doi:10.1021/la960022s](http://dx.doi.org/10.1021/la960022s)
Chaikittisilp, W., Kim, H. J., and Jones, C. W. (2011a). Mesoporous alumina
supported amines as potential steam-stable adsorbents for capturing CO2 from
simulated flue gas and ambient air. _Energy_ _Fuel_ 25, 5528–5537. [doi:10.1021/](http://dx.doi.org/10.1021/ef201224v)
[ef201224v](http://dx.doi.org/10.1021/ef201224v)
Chaikittisilp, W., Lunn, J. D., Shantz, D. F., and Jones, C. W. (2011b). Poly(L-lysine)

brush-mesoporous silica hybrid material as a biomolecule-based adsorbent for
CO2 capture from simulated flue gas and air. _Chem._ _Eur._ _J._ 17, 10556–10561.
[doi:10.1002/chem.201101480](http://dx.doi.org/10.1002/chem.201101480)
Chandra, V., Yu, S. U., Kim, S. H., Yoon, Y. S., Kim, D. Y., Kwon, A. H., et al.

(2012). Highly selective CO2 capture on N-doped carbon produced by chemical
activation of polypyrrole functionalized graphene sheets. _Chem._ _Commun._ 48,
[735–737. doi:10.1039/c1cc15599g](http://dx.doi.org/10.1039/c1cc15599g)
Chen, C., Kim, J., and Ahn, W. S. (2012). Efficient carbon dioxide capture over a

nitrogen-rich carbon having a hierarchical micro-mesopore structure. _Fuel_ 95,
[360–364. doi:10.1016/j.fuel.2011.10.072](http://dx.doi.org/10.1016/j.fuel.2011.10.072)
Chen, C., Son, W. J., You, K. S., Ahn, J. W., and Ahn, W. S. (2010). Carbon dioxide

capture using amine-impregnated HMS having textural mesoporosity. _Chem._
_Eng. J._ [161, 46–52. doi:10.1016/j.cej.2010.04.019](http://dx.doi.org/10.1016/j.cej.2010.04.019)
Chen, C., Yang, S. T., Ahn, W. S., and Ryoo, R. (2009). Amine-impregnated sil
ica monolith with a hierarchical pore structure: enhancement of CO2 capture
capacity. _Chem. Commun._ [24, 3627–3629. doi:10.1039/b905589d](http://dx.doi.org/10.1039/b905589d)
Chen, Z. H., Deng, S. B., Wei, H. R., Wang, B., Huang, J., and Yu, G. (2013).

Polyethylenimine-impregnatedresinforhighCO2 adsorption:anefficientadsorbent for CO2 capture from simulated flue gas and ambient air. _ACS Appl. Mater._
_Interfaces_ [5, 6937–6945. doi:10.1021/am400661b](http://dx.doi.org/10.1021/am400661b)
Choi, S., Drese, J. H., and Jones, C. W. (2009). Adsorbent materials for carbon diox
ide capture from large anthropogenic point sources. _ChemSusChem_ 2, 796–854.
[doi:10.1002/cssc.200900036](http://dx.doi.org/10.1002/cssc.200900036)
Chu, S., and Majumdar, A. (2012). Opportunities and challenges for a sustainable

energy future. _Nature_ [488, 294–303. doi:10.1038/nature11475](http://dx.doi.org/10.1038/nature11475)
[CO2Now.org. (2014). Available at: http://co2now.org/](http://co2now.org/)
Crowley, T. J. (2000). Causes of climate change over the past 1000 years. _Science_ 289,

[270–277. doi:10.1126/science.289.5477.270](http://dx.doi.org/10.1126/science.289.5477.270)
Davis, M. E. (2002). Ordered porous materials for emerging applications. _Nature_

[417, 813–821. doi:10.1038/nature00785](http://dx.doi.org/10.1038/nature00785)
Dawson, R., Cooper, A. I., and Adams, D. J. (2012). Nanoporous organic polymer

networks. _Prog. Polym. Sci._ [37,530–563. doi:10.1016/j.progpolymsci.2011.09.002](http://dx.doi.org/10.1016/j.progpolymsci.2011.09.002)
de Souza, L. K. C., Wickramaratne, N. P., Ello, A. S., Costa, M. J. F., da Costa, C.

E. F., and Jaroniec, M. (2013). Enhancement of CO2 adsorption on phenolic
resin-based mesoporous carbons by KOH activation. _Carbon N. Y._ 65, 334–340.
[doi:10.1016/j.carbon.2013.08.034](http://dx.doi.org/10.1016/j.carbon.2013.08.034)
Donat, F., Florin, N. H., Anthony, E. J., and Fennell, P. S. (2012). Influence of high
temperature steam on the reactivity of CaO sorbent for CO2 capture. _Environ._
_Sci. Technol._ [46, 1262–1269. doi:10.1021/es202679w](http://dx.doi.org/10.1021/es202679w)
Drage, T. C., Arenillas, A., Smith, K. M., Pevida, C., Piippo, S., and Snape, C. E.

(2007). Preparation of carbon dioxide adsorbents from the chemical activation of urea-formaldehyde and melamine-formaldehyde resins. _Fuel_ 86, 22–31.
[doi:10.1016/j.fuel.2006.07.003](http://dx.doi.org/10.1016/j.fuel.2006.07.003)
Drese, J. H., Choi, S., Didas, S. A., Bollini, P., Gray, M. L., and Jones, C. W.

(2012). Effect of support structure on CO2 adsorption properties of poreexpanded hyperbranched aminosilicas. _Microporous_ _Mesoporous_ _Mater._ 151,
[231–240. doi:10.1016/j.micromeso.2011.10.031](http://dx.doi.org/10.1016/j.micromeso.2011.10.031)
Drese, J. H., Choi, S., Lively, R. P., Koros, W. J., Fauth, D. J., Gray, M. L., et al. (2009).

Synthesis-structure-property relationships for hyperbranched aminosilica CO2
adsorbents. _Adv. Funct. Mater._ [19, 3821–3832. doi:10.1002/adfm.200901461](http://dx.doi.org/10.1002/adfm.200901461)

Du, N. Y., Park, H. B., Dal-Cin, M. M., and Guiver, M. D. (2012). Advances in

high permeability polymeric membrane materials for CO2 separations. _Energy_
_Environ. Sci._ [5, 7306–7322. doi:10.1039/c1ee02668b](http://dx.doi.org/10.1039/c1ee02668b)
Garcia, S., Pis, J. J., Rubiera, F., and Pevida, C. (2013). Predicting mixed-gas adsorp
tion equilibria on activated carbon for precombustion CO2 capture. _Langmuir_
[29, 6042–6052. doi:10.1021/la4004998](http://dx.doi.org/10.1021/la4004998)
Goeppert,A.,Meth,S.,Prakash,G. K. S.,and Olah,G. A. (2010). Nanostructured sil
ica as a support for regenerable high-capacity organoamine-based CO2 sorbents.
_Energy Environ. Sci._ [3, 1949–1960. doi:10.1039/c0ee00136h](http://dx.doi.org/10.1039/c0ee00136h)
Graves, C., Ebbesen, S. D., Mogensen, M., and Lackner, K. S. (2011). Sustainable

hydrocarbon fuels by recycling CO2 and H2O with renewable or nuclear energy.
_Renew. Sustain. Energ. Rev._ [15, 1–23. doi:10.1016/j.rser.2010.07.014](http://dx.doi.org/10.1016/j.rser.2010.07.014)
Hao, G. P., Li, W. C., Qian, D., and Lu, A. H. (2010). Rapid synthesis of nitrogen
doped porous carbon monolith for CO2 capture. _Adv._ _Mater._ 22, 853–857.
[doi:10.1002/adma.200903765](http://dx.doi.org/10.1002/adma.200903765)
Hao, G. P., Li, W. C., Qian, D., Wang, G. H., Zhang, W. P., Zhang, T., et al.

(2011). Poly(benzoxazine-co-resol)-based porous carbon monoliths and their
application as high-performance CO2 capture sorbents. _J. Am. Chem. Soc._ 133,
[11378–11388. doi:10.1021/ja203857g](http://dx.doi.org/10.1021/ja203857g)
Harlick, P. J. E., and Sayari, A. (2007). Applications of pore-expanded meso
porous silica. 5. Triamine grafted material with exceptional CO2 dynamic
and equilibrium adsorption performance. _Ind._ _Eng._ _Chem._ _Res._ 46, 446–458.
[doi:10.1021/ie060774+](http://dx.doi.org/10.1021/ie060774+)
Held, I. M., and Soden, B. J. (2000). Water vapor feedback and global warming.

_Annu. Rev. Energy Environ._ [25, 441–475. doi:10.1146/annurev.energy.25.1.441](http://dx.doi.org/10.1146/annurev.energy.25.1.441)
Heydari-Gorji, A., and Sayari, A. (2012). Thermal, oxidative, and CO2-induced

degradation of supported polyethylenimine adsorbents. _Ind._ _Eng._ _Chem._ _Res._
[51, 6887–6894. doi:10.1021/ie3003446](http://dx.doi.org/10.1021/ie3003446)
Hicks, J. C., Drese, J. H., Fauth, D. J., Gray, M. L., Qi, G. G., and Jones, C. W. (2008).

Designing adsorbents for CO2 capture from flue gas-hyperbranched aminosilicas capable of capturing CO2 reversibly. _J._ _Am._ _Chem._ _Soc._ 130, 2902–2903.
[doi:10.1021/ja077795v](http://dx.doi.org/10.1021/ja077795v)
Hoffert, M. I., Caldeira, K., Jain, A. K., Haites, E. F., Harvey, L. D. D., Potter, S. D.,

et al. (1998). Energy implications of future stabilization of atmospheric CO2
content. _Nature_ [395, 881–884. doi:10.1038/27638](http://dx.doi.org/10.1038/27638)
Hu, X., Radosz, M., Cychosz, K. A., and Thommes, M. (2011). CO2-filling capacity

and selectivity of carbon nanopores:synthesis,texture,and pore-size distribution
from quenched-solid density functional theory (QSDFT). _Environ. Sci. Technol._
[45, 7068–7074. doi:10.1021/es200782s](http://dx.doi.org/10.1021/es200782s)
Jang,D. I.,and Park,S. J. (2012). Influence of nickel oxide on carbon dioxide adsorp
tion behaviors of activated carbons. _Fuel_ [102, 439–444. doi:10.1016/j.fuel.2012.](http://dx.doi.org/10.1016/j.fuel.2012.03.052)
[03.052](http://dx.doi.org/10.1016/j.fuel.2012.03.052)
Jones, C. W. (2011). CO2 capture from dilute gases as a component of mod
ern global carbon management. _Annu._ _Rev._ _Chem._ _Biomol._ _Eng._ 2, 31–52.
[doi:10.1146/annurev-chembioeng-061010-114252](http://dx.doi.org/10.1146/annurev-chembioeng-061010-114252)
Kadib, A. E., Chimenton, R., Sachse, A., Fajula, F., Galarneau, A., and Coq, B.

(2009). Functionalized inorganic monolithic microreactors for high productivity in fine chemicals catalytic synthesis. _Angew._ _Chem._ _Int._ _Ed._ 48, 4969–4972.
[doi:10.1002/anie.200805580](http://dx.doi.org/10.1002/anie.200805580)
Kalyani,P.,and Anitha,A. (2013). Biomass carbon & its prospects in electrochemical

energy systems. _Int._ _J._ _Hydrogen_ _Energy_ 38, 4034–4045. [doi:10.1016/j.ijhydene.](http://dx.doi.org/10.1016/j.ijhydene.2013.01.048)
[2013.01.048](http://dx.doi.org/10.1016/j.ijhydene.2013.01.048)
Karadas, F., Atilhan, M., and Aparicio, S. (2010). Review on the use of ionic liquids

(ILs) as alternative fluids for CO2 capture and natural gas sweetening. _Energy_
_Fuel_ [24, 5817–5828. doi:10.1021/ef1011337](http://dx.doi.org/10.1021/ef1011337)
Kaya, Y. (1995). The role of CO2 removal and disposal. _Energy Convers. Manag._ 36,

[375–380. doi:10.1016/0196-8904(95)00025-9](http://dx.doi.org/10.1016/0196-8904%0x2895%0x2900025-9)
Kim, B. J., Cho, K. S., and Park, S. J. (2012). Copper oxide-decorated porous carbons

for carbon dioxide adsorption behaviors. _J. Colloid Interface Sci._ 342, 575–578.
[doi:10.1016/j.jcis.2009.10.045](http://dx.doi.org/10.1016/j.jcis.2009.10.045)
Knofel, C., Martin, C., Hornebecq, V., and Llewellyn, P. L. (2009). Study of carbon

dioxide adsorption on mesoporous aminopropylsilane-functionalized silica and
titania combining microcalorimetry and in situ infrared spectroscopy. _J._ _Phys._
_Chem. C_ [113, 21726–21734. doi:10.1021/jp907054h](http://dx.doi.org/10.1021/jp907054h)
Kumar, P., Barrett, D. M., Delwiche, M. J., and Stroeve, P. (2009). Methods for pre
treatment of lignocellulosic biomass for efficient hydrolysis and biofuel production. _Ind. Eng. Chem. Res._ [48, 3713–3729. doi:10.1021/ie801542g](http://dx.doi.org/10.1021/ie801542g)

Li, F. X., and Fan, L. S. (2008). Clean coal conversion processes - progress and

challenges. _Energy Environ. Sci._ [1, 248–267. doi:10.1039/b809218b](http://dx.doi.org/10.1039/b809218b)
Li, Q., Yang, J. P., Feng, D., Wu, Z. X., Wu, Q. L., Park, S. S., et al. (2010). Facile

synthesis of porous carbon nitride spheres with hierarchical three-dimensional
mesostructures for CO2 capture. _Nano Res._ [3,632–642. doi:10.1007/s12274-010-](http://dx.doi.org/10.1007/s12274-010-0023-7)
[0023-7](http://dx.doi.org/10.1007/s12274-010-0023-7)
Liang, Z., Fadhel, B., Schneider, C. J., and Chaffee, A. L. (2008). Stepwise growth of

melamine-based dendrimers into mesopores and their CO2 adsorption properties. _Microporous Mesoporous Mater._ [111, 536–543. doi:10.1016/j.micromeso.](http://dx.doi.org/10.1016/j.micromeso.2007.08.030)
[2007.08.030](http://dx.doi.org/10.1016/j.micromeso.2007.08.030)
Liang, Z. J., Fadhel, B., Schneider, C. J., and Chaffee, A. L. (2009). Adsorption of

CO2 on mesocellular siliceous foam iteratively functionalized with dendrimers.
_Adsorption_ [15, 429–437. doi:10.1007/s10450-009-9192-7](http://dx.doi.org/10.1007/s10450-009-9192-7)
Liu, L., Deng, Q. F., Ma, T. Y., Lin, X. Z., Hou, X. X., Liu, Y. P., et al. (2011). Ordered

mesoporous carbons: citric acid-catalyzed synthesis, nitrogen doping and CO2
capture. _J. Mater. Chem._ [21, 16001–16009. doi:10.1039/c1jm12887f](http://dx.doi.org/10.1039/c1jm12887f)
Liu, Y. M., Shi, J. J., Chen, J., Ye, Q., Pan, H., Shao, Z. H., et al. (2010).

Dynamic performance of CO2 adsorption with tetraethylenepentamine-loaded
KIT-6. _Microporous_ _Mesoporous_ _Mater._ 134, 16–21. [doi:10.1016/j.micromeso.](http://dx.doi.org/10.1016/j.micromeso.2010.05.002)
[2010.05.002](http://dx.doi.org/10.1016/j.micromeso.2010.05.002)
Lohe, M. R., Rose, M., and Kaskel, S. (2009). Metal-organic framework (MOF)

aerogels with high micro- and macroporosity. _Chem. Commun._ 40, 6056–6058.
[doi:10.1039/b910175f](http://dx.doi.org/10.1039/b910175f)
Ma, T. Y., Liu, L., and Yuan, Z. Y. (2013). Direct synthesis of ordered mesoporous

carbons. _Chem. Soc. Rev._ [42, 3977–4003. doi:10.1039/c2cs35301f](http://dx.doi.org/10.1039/c2cs35301f)
Ma, X. L., Wang, X. X., and Song, C. S. (2009). “Molecular basket” sorbents for

separation of CO2 and H2S from various gas streams. _J._ _Am._ _Chem._ _Soc._ 131,
[5777–5783. doi:10.1021/ja8074105](http://dx.doi.org/10.1021/ja8074105)
MacDowell, N., Florin, N., Buchard, A., Hallett, J., Galindo, A., Jackson, G., et al.

(2010). An overview of CO2 capture technologies. _Energy_ _Environ._ _Sci._ 3,
[1645–1669. doi:10.1039/c004106h](http://dx.doi.org/10.1039/c004106h)
Markewitz, P., Kuckshinrichs, W., Leitner, W., Linssen, J., Zapp, P., Bongartz, R.,

et al. (2012). Worldwide innovations in the development of carbon capture
technologies and the utilization of CO2. _Energy_ _Environ._ _Sci._ 5, 7281–7305.
[doi:10.1039/c2ee03403d](http://dx.doi.org/10.1039/c2ee03403d)
Martin, C. F., Plaza, M. G., Garcia, S., Pis, J. J., Rubiera, F., and Pevida, C. (2011).

Microporous phenol-formaldehyde resin-based adsorbents for pre-combustion
CO2 capture. _Fuel_ [90, 2064–2072. doi:10.1016/j.fuel.2011.01.019](http://dx.doi.org/10.1016/j.fuel.2011.01.019)
Martin-Martinez, J. M., Torregrosa-Macia, R., and Mittelmeijer-Hazeleger, M. C.

(1995). Mechanisms of adsorption of CO2 in the micropores of activated
anthracite. _Fuel_ [74, 111–114. doi:10.1016/0016-2361(94)P4340-8](http://dx.doi.org/10.1016/0016-2361%0x2894%0x29P4340-8)
Mikkelsen, M., Jorgensen, M., and Krebs, F. C. (2010). The teraton challenge. A

review of fixation and transformation of carbon dioxide. _Energy Environ. Sci._ 3,
[43–81. doi:10.1039/b912904a](http://dx.doi.org/10.1039/b912904a)
Mohan, D., and Pittman, C. U. (2006). Activated carbons and low cost adsorbents

for remediation of tri- and hexavalent chromium from water. _J. Hazard. Mater._
[137, 762–811. doi:10.1016/j.jhazmat.2006.06.060](http://dx.doi.org/10.1016/j.jhazmat.2006.06.060)
Nandi, M., Okada, K., Dutta, A., Bhaumik, A., Maruyama, J., Derks, D., et al. (2012).

Unprecedented CO2 uptake over highly porous N-doped activated carbon
monoliths prepared by physical activation. _Chem._ _Commun._ 48, 10283–10285.
[doi:10.1039/c2cc35334b](http://dx.doi.org/10.1039/c2cc35334b)
Panwar, N. L., Kaushik, S. C., and Kothari, S. (2011). Role of renewable energy

sources in environmental protection: a review. _Renew._ _Sustain._ _Energ._ _Rev._ 15,
[1513–1524. doi:10.1016/j.rser.2010.11.037](http://dx.doi.org/10.1016/j.rser.2010.11.037)
Patino, J., Gutierrez, M. C., Carriazo, D., Ania, C. O., Parra, J. B., Ferrer, M. L., et al.

(2012). Deep eutectic assisted synthesis of carbon adsorbents highly suitable
for low-pressure separation of CO2-CH4 gas mixtures. _Energy_ _Environ._ _Sci._ 5,
[8699–8707. doi:10.1039/c2ee22029f](http://dx.doi.org/10.1039/c2ee22029f)
Patz, J. A., Campbell-Lendrum, D., Holloway, T., and Foley, J. A. (2005). Impact of

regional climate change on human health. _Nature_ 438, 310–317. [doi:10.1038/](http://dx.doi.org/10.1038/nature04188)
[nature04188](http://dx.doi.org/10.1038/nature04188)
Pevida, C., Drage, T. C., and Snape, C. E. (2008). Silica-templated melamine
formaldehyde resin derived adsorbents for CO2 capture. _Carbon_ _N._ _Y._ 46,
[1464–1474. doi:10.1016/j.carbon.2008.06.026](http://dx.doi.org/10.1016/j.carbon.2008.06.026)
Plaza, M. G., Pevida, C., Arias, B., Fermoso, J., Casal, M. D., Martin, C. F., et al.

(2009). Development of low-cost biomass-based adsorbents for postcombustion
CO2 capture. _Fuel_ [88, 2442–2447. doi:10.1016/j.fuel.2009.02.025](http://dx.doi.org/10.1016/j.fuel.2009.02.025)

Presser, V., McDonough, J., Yeon, S. H., and Gogotsi, Y. (2011). Effect of pore size

on carbon dioxide sorption by carbide derived carbon. _Energy_ _Environ._ _Sci._ 4,
[3059–3066. doi:10.1039/c1ee01176f](http://dx.doi.org/10.1039/c1ee01176f)
Przepiorski, J., Skrodzewicz, M., and Morawski, A. W. (2004). High temperature

ammonia treatment of activated carbon for enhancement of CO2 adsorption.
_Appl. Surf. Sci._ [225, 235–242. doi:10.1016/j.apsusc.2003.10.006](http://dx.doi.org/10.1016/j.apsusc.2003.10.006)
Qi, G. G., Fu, L. L., Choi, B. H., and Giannelis, E. P. (2012). Efficient CO2 sor
bents based on silica foam with ultra-large mesopores. _Energy_ _Environ._ _Sci._ 5,
[7368–7375. doi:10.1039/c2ee21394j](http://dx.doi.org/10.1039/c2ee21394j)
Qi, G. G., Wang, Y. B., Estevez, L., Duan, X. N., Anako, N., Park, A. H. A., et al.

(2011). High efficiency nanocomposite sorbents for CO2 capture based on
amine-functionalized mesoporous capsules. _Energy_ _Environ._ _Sci._ 4, 444–452.
[doi:10.1039/c0ee00213e](http://dx.doi.org/10.1039/c0ee00213e)
Ren, X. M., Chen, C. L., Nagatsu, M., and Wang, X. K. (2011). Carbon nanotubes

as adsorbents in environmental pollution management: a review. _Chem. Eng. J._
[170, 395–410. doi:10.1016/j.cej.2010.08.045](http://dx.doi.org/10.1016/j.cej.2010.08.045)
Ridha, F. N., Manovic, V., Wu, Y. H., Macchi, A., and Anthony, E. J. (2013).

Pelletized CaO-based sorbents treated with organic acids for enhanced CO2
capture in Ca-looping cycles. _Int._ _J._ _Greenhouse_ _Gas_ _Control_ 17, 357–365.
[doi:10.1016/j.ijggc.2013.05.009](http://dx.doi.org/10.1016/j.ijggc.2013.05.009)
Rochelle, G. T. (2009). Amine scrubbing for CO2 capture. _Science_ 325, 1652–1654.

[doi:10.1126/science.1176731](http://dx.doi.org/10.1126/science.1176731)
Sangeeta, Moka, S., Pande, M., Rani, M., Gakhar, R., Sharma, M., et al. (2014). Alter
native fuels: an overview of current trends and scope for future. _Renew. Sustain._
_Energ. Rev._ [32, 697–712. doi:10.1016/j.rser.2014.01.023](http://dx.doi.org/10.1016/j.rser.2014.01.023)
Sayari, A., and Belmabkhout, Y. (2010). Stabilization of amine-containing CO2

adsorbents: dramatic effect of water vapor. _J. Am._ _Chem._ _Soc._ 132, 6312–6314.
[doi:10.1021/ja1013773](http://dx.doi.org/10.1021/ja1013773)
Sayari, A., Belmabkhout, Y., and Serna-Guerrero, R. (2011). Flue gas treatment via

CO2 adsorption. _Chem. Eng. J._ [171, 760–774. doi:10.1016/j.cej.2011.02.007](http://dx.doi.org/10.1016/j.cej.2011.02.007)
Sayari, A., Heydari-Gorji, A., and Yang, Y. (2012). CO2-induced degradation of

amine-containing adsorbents: reaction products and pathways. _J._ _Am._ _Chem._
_Soc._ [134, 13834–13842. doi:10.1021/ja304888a](http://dx.doi.org/10.1021/ja304888a)
Seema, H., Kemp, K. C., Le, N. H., Park, S. W., Chandra, V., Lee, J. W., et al. (2014).

Highly selective CO2 capture by S-doped microporous carbon materials. _Carbon_
_N. Y._ [66, 320–326. doi:10.1016/j.carbon.2013.09.006](http://dx.doi.org/10.1016/j.carbon.2013.09.006)
Serna-Guerrero, R., Belmabkhout, Y., and Sayari, A. (2010). Further investigations

of CO2 capture using triamine-grafted pore-expanded mesoporous silica. _Chem._
_Eng. J._ [158, 513–519. doi:10.1016/j.cej.2010.01.041](http://dx.doi.org/10.1016/j.cej.2010.01.041)
Serna-Guerrero, R., Da’na, E., and Sayari, A. (2008). New insights into the inter
actions of CO2 with amine-functionalized silica. _Ind._ _Eng._ _Chem._ _Res._ 47,
[9406–9412. doi:10.1021/ie801186g](http://dx.doi.org/10.1021/ie801186g)
Sevilla, M., and Fuertes, A. B. (2011). Sustainable porous carbons with a superior

performance for CO2 capture. _Energy Environ. Sci._ [4, 1765–1771. doi:10.1039/](http://dx.doi.org/10.1039/c0ee00784f)
[c0ee00784f](http://dx.doi.org/10.1039/c0ee00784f)
Sevilla, M., and Mokaya, R. (2014). Energy storage applications of activated car
bons: supercapacitors and hydrogen storage. _Energy Environ. Sci._ 7, 1250–1280.
[doi:10.1002/cssc.201300295](http://dx.doi.org/10.1002/cssc.201300295)
Sevilla, M., Valle-Vigon, P., and Fuertes, A. B. (2011). N-doped polypyrrole
based porous carbons for CO2 capture. _Adv._ _Funct._ _Mater._ 21, 2781–2787.
[doi:10.1002/adfm.201100291](http://dx.doi.org/10.1002/adfm.201100291)
Shafeeyan, M. S., Daud, W. M. A. W., Houshmand, A., and Arami-Niya, A. (2011).

Ammonia modification of activated carbon to enhance carbon dioxide adsorption: effect of pre-oxidation. _Appl._ _Surf._ _Sci._ 257, 3936–3942. [doi:10.1016/j.](http://dx.doi.org/10.1016/j.apsusc.2010.11.127)
[apsusc.2010.11.127](http://dx.doi.org/10.1016/j.apsusc.2010.11.127)
Shafeeyan, M. S., Daud, W. M. A. W., Houshmand, A., and Shamiri, A. (2010). A

review on surface modification of activated carbon for carbon dioxide adsorption. _J. Anal. Appl. Pyrolysis_ [89, 143–151. doi:10.1016/j.jaap.2010.07.006](http://dx.doi.org/10.1016/j.jaap.2010.07.006)
Shao, X. H., Feng, Z. H., Xue, R. S., Ma, C. C., Wang, W. C., Peng, X., et al. (2011).

Adsorption of CO2, CH4, CO2/N2 and CO2/CH4 in novel activated carbon
beads: preparation, measurements and simulation. _AIChE_ _J._ 57, 3042–3051.
[doi:10.1002/aic.12515](http://dx.doi.org/10.1002/aic.12515)
Shen, W. Z., Zhang, S. C., He, Y., Li, J. F., and Fan, W. B. (2011). Hierarchical porous

polyacrylonitrile-based activated carbon fibers for CO2 capture. _J. Mater. Chem._
[21, 14036–14040. doi:10.1039/c1jm12585k](http://dx.doi.org/10.1039/c1jm12585k)
Shi, L., Yang, G. H., Tao, K., Yoneyama, Y., Tan, Y. S., and Tsubaki, N. (2013).

An introduction of CO2 conversion by dry reforming with methane and new

route of low-temperature methanol synthesis. _Acc._ _Chem._ _Res._ 46, 1838–1847.
[doi:10.1021/ar300217j](http://dx.doi.org/10.1021/ar300217j)
Siglinda, P., and Centi, G. (2014). CO2 Recycling: a key strategy to introduce

green energy in the chemical production chain. _ChemSusChem_ 7, 1274–1282.
[doi:10.1002/cssc.201300926](http://dx.doi.org/10.1002/cssc.201300926)
Silvestre-Albero, J., Wahby, A., Sepulveda-Escribano, A., Martinez-Escandell, M.,

Kaneko, K., and Rodriguez-Reinoso, F. (2011). Ultrahigh CO2 adsorption capacity on carbon molecular sieves at room temperature. _Chem._ _Commun._ 47,
[6840–6842. doi:10.1039/c1cc11618e](http://dx.doi.org/10.1039/c1cc11618e)
Son, W. J., Choi, J. S., and Ahn, W. S. (2008). Adsorptive removal of carbon diox
ide using polyethyleneimine-loaded mesoporous silica materials. _Microporous_
_Mesoporous Mater._ [113, 31–40. doi:10.1016/j.jhazmat.2010.11.125](http://dx.doi.org/10.1016/j.jhazmat.2010.11.125)
Song, C. (2006). Global challenges and strategies for control, conversion and

utilization of CO2 for sustainable development involving energy, catalysis,
adsorption and chemical processing. _Catal._ _Today_ 115, 2–32. [doi:10.1016/j.](http://dx.doi.org/10.1016/j.cattod.2006.02.029)
[cattod.2006.02.029](http://dx.doi.org/10.1016/j.cattod.2006.02.029)
Srinivas, G., Krungleviciute, V., Guo, Z. X., and Yildirim, T. (2014). Excep
tional CO2 capture in a hierarchically porous carbon with simultaneous high
surface area and pore volume. _Energy_ _Environ._ _Sci._ 7, 335–342. [doi:10.1039/](http://dx.doi.org/10.1039/c3ee42918k)
[c3ee42918k](http://dx.doi.org/10.1039/c3ee42918k)
Sumida, K., Rogow, D. L., Mason, J. A., McDonald, T. M., Bloch, E. D., Herm, Z. R.,

et al. (2012). Carbon dioxide capture in metal-organic frameworks. _Chem. Rev._
[112, 724–781. doi:10.1021/cr2003272](http://dx.doi.org/10.1021/cr2003272)
Sun, N. N., Sun, C. G., Liu, H., Liu, J. J., Stevens, L., Drage, T., et al. (2013). Synthesis,

characterization and evaluation of activated spherical carbon materials for CO2
capture. _Fuel_ [113, 854–862. doi:10.1016/j.fuel.2013.03.047](http://dx.doi.org/10.1016/j.fuel.2013.03.047)
Sunil, D. S., and Merched, A. (2014). A critical review of existing strategies for emis
sion control in the monoethanolamine-based carbon capture process and some
recommendations for improved strategies. _Fuel_ [121,178–188. doi:10.1016/j.fuel.](http://dx.doi.org/10.1016/j.fuel.2013.12.023)
[2013.12.023](http://dx.doi.org/10.1016/j.fuel.2013.12.023)
Swain, P. K., Das, L. M., and Naik, S. N. (2011). Biomass to liquid: a prospective

challenge to research and development in 21st century. _Renew._ _Sustain._ _Energ._
_Rev._ [15, 4917–4933. doi:10.1016/j.rser.2011.07.061](http://dx.doi.org/10.1016/j.rser.2011.07.061)
Toftegaard, M. B., Brix, J., Jensen, P. A., Glarborg, P., and Jensen, A. D. (2010).

Oxy-fuel combustion of solid fuels. _Prog._ _Energy_ _Combust._ _Sci._ 36, 581–625.
[doi:10.1016/j.pecs.2010.02.001](http://dx.doi.org/10.1016/j.pecs.2010.02.001)
Vaidya,P.D.,andKenig,E.Y.(2007).CO2-alkanolaminereactionkinetics:areviewof

recent studies. _Chem. Eng. Technol._ [30, 1467–1474. doi:10.1002/ceat.200700268](http://dx.doi.org/10.1002/ceat.200700268)
Vasireddy, S., Morreale, B., Cugini, A., Song, C., and Spivey, J. J. (2011). Clean liquid

fuels from direct coal liquefaction: chemistry, catalysis, technological status and
challenges. _Energy Environ. Sci._ [4, 311–345. doi:10.1039/c0ee00097c](http://dx.doi.org/10.1039/c0ee00097c)
Vishnyakov, A., Ravikovitch, P. I., and Neimark, A. V. (1999). Molecular level

models for CO2 sorption in nanopores. _Langmuir_ [15, 8736–8742. doi:10.1021/](http://dx.doi.org/10.1021/la990726c)
[la990726c](http://dx.doi.org/10.1021/la990726c)
Wahby, A., Ramos-Fernandez, J. M., Martinez-Escandell, M., Sepulveda-Escribano,

A., Silvestre-Albero, J., and Rodriguez-Reinoso, F. (2010). High-surface-area carbon molecular sieves for selective CO2 adsorption. _ChemSusChem_ 3, 974–981.
[doi:10.1002/cssc.201000083](http://dx.doi.org/10.1002/cssc.201000083)
Wang, D. X., Ma, X. L., Sentorun-Shalaby, C., and Song, C. S. (2012). Development

of carbon-based “molecular basket” sorbent for CO2 capture. _Ind._ _Eng._ _Chem._
_Res._ [51, 3048–3057. doi:10.1021/ie2022543](http://dx.doi.org/10.1021/ie2022543)
Wang, L. F., and Yang, R. T. (2011). Increasing selective CO2 adsorption on amine
grafted SBA-15 by increasing silanol density. _J. Phys. Chem. C_ 115, 21264–21272.
[doi:10.1021/jp206976d](http://dx.doi.org/10.1021/jp206976d)
Wang, L. F., and Yang, R. T. (2012). Significantly increased CO2 adsorption perfor
mance of nanostructured templated carbon by tuning surface area and nitrogen
doping. _J. Phys. Chem. C_ [116, 1099–1106. doi:10.1021/jp2100446](http://dx.doi.org/10.1021/jp2100446)
Wang, Q., Luo, J., Zhong, Z., and Borgna, A. (2011a). CO2 capture by solid adsor
bents and their applications current status and new trends. _Energy Environ. Sci._
[4, 42–55. doi:10.1039/c0ee00064g](http://dx.doi.org/10.1039/c0ee00064g)
Wang, S. P., Yan, S. L., Ma, X. B., and Gong, J. L. (2011b). Recent advances in cap
ture of carbon dioxide using alkali-metal-based oxides. _Energy_ _Environ._ _Sci._ 4,
[3805–3819. doi:10.1039/c1ee01116b](http://dx.doi.org/10.1039/c1ee01116b)
Wang, D. X., Sentorun-Shalaby, C., Ma, X. L., and Song, C. S. (2011c). High-capacity

and low-cost carbon-based“molecular basket”sorbent for CO2 capture from flue
gas. _Energy Fuel_ [25, 456–458. doi:10.1021/ef101364c](http://dx.doi.org/10.1021/ef101364c)
Wang, X. X., Schwartz, V., Clark, J. C., Ma, X. L., Overbury, S. H., Xu, X. C.,

et al. (2009). Infrared study of CO2 sorption over “molecular basket” sorbent

consisting of polyethylenimine-modified mesoporous molecular sieve. _J._ _Phys._
_Chem. C_ [113, 7260–7268. doi:10.1021/jp809946y](http://dx.doi.org/10.1021/jp809946y)
Wang, X. X., and Song, C. S. (2012). Temperature-programmed desorption of

CO2 from polyethylenimine-loaded SBA-15 as molecular basket sorbents. _Catal._
_Today_ [194, 44–52. doi:10.1016/j.cattod.2012.08.008](http://dx.doi.org/10.1016/j.cattod.2012.08.008)
Wei, H. R., Deng, S. B., Hu, B. Y., Chen, Z. H., Wang, B., Huang, J., et al.

(2012). Granular bamboo-derived activated carbon for high CO2 adsorption: the dominant role of narrow micropores. _ChemSusChem_ 5, 2354–2360.
[doi:10.1002/cssc.201200570](http://dx.doi.org/10.1002/cssc.201200570)
Wen, J. J., Gu, F. N., Wei, F., Zhou, Y., Lin, W. G., Yang, J., et al. (2010). One-pot

synthesis of the amine-modified meso-structured monolith CO2 adsorbent. _J._
_Mater. Chem._ [20, 2840–2846. doi:10.1039/b920027d](http://dx.doi.org/10.1039/b920027d)
White, R. J., Budarin, V., Luque, R., Clark, J. H., and Macquarrie, D. J. (2009). Tune
able porous carbonaceous materials from renewable resources. _Chem. Soc. Rev._
[38, 3401–3418. doi:10.1039/b822668g](http://dx.doi.org/10.1039/b822668g)
Wickramaratne, N. P., and Jaroniec, M. (2013). Importance of small micropores in

CO2 capture by phenolic resin-based activated carbon spheres. _J. Mater. Chem._
_A_ [1, 112–116. doi:10.1039/c2ta00388k](http://dx.doi.org/10.1039/c2ta00388k)
Williams, J. L. (2001). Monolith structures, materials, properties and uses. _Catal._

_Today_ [69, 3–9. doi:10.1016/S0920-5861(01)00348-0](http://dx.doi.org/10.1016/S0920-5861%0x2801%0x2900348-0)
Xia,Y. D.,Mokaya, R.,Walker, G. S.,and Zhu,Y. Q. (2011). Superior CO2 adsorption

capacity on N-doped, high-surface-area, microporous carbons templated from
zeolite. _Adv. Energy Mater._ [1, 678–683. doi:10.1002/aenm.201100061](http://dx.doi.org/10.1002/aenm.201100061)
Xia, Y. D., Zhu, Y. Q., and Tang, Y. (2012). Preparation of sulfur-doped microp
orous carbons for the storage of hydrogen and carbon dioxide. _Carbon N. Y._ 50,
[5543–5553. doi:10.1016/j.carbon.2012.07.044](http://dx.doi.org/10.1016/j.carbon.2012.07.044)
Xu, X. C., Song, C. S., Andresen, J. M., Miller, B. G., and Scaroni, A. W. (2002).

Novel polyethylenimine-modified mesoporous molecular sieve of MCM-41
type as high-capacity adsorbent for CO2 capture. _Energy_ _Fuel_ 16, 1463–1469.
[doi:10.1021/ef020058u](http://dx.doi.org/10.1021/ef020058u)
Xu, X. C., Song, C. S., Andresen, J. M., Miller, B. G., and Scaroni, A. W. (2003).

Preparation and characterization of novel CO2 “molecular basket” adsorbents
based on polymer-modified mesoporous molecular sieve MCM-41. _Microporous_
_Mesoporous Mater._ [62, 29–45. doi:10.1016/S1387-1811(03)00388-3](http://dx.doi.org/10.1016/S1387-1811%0x2803%0x2900388-3)
Yang, S. T., Kim, J. Y., Kim, J., and Ahn, W. S. (2012). CO2 capture over amine
functionalized MCM-22, MCM-36 and ITQ-2. _Fuel_ [97, 435–442. doi:10.1016/j.](http://dx.doi.org/10.1016/j.fuel.2012.03.034)
[fuel.2012.03.034](http://dx.doi.org/10.1016/j.fuel.2012.03.034)
Zelenak, V., Badanicova, M., Halamova, D., Cejka, J., Zukal, A., Murafa, N., et al.

(2008).Amine-modified ordered mesoporous silica: effect of pore size on carbon
dioxide capture. _Chem. Eng. J._ [144, 336–342. doi:10.1016/j.cej.2008.07.025](http://dx.doi.org/10.1016/j.cej.2008.07.025)
Zhang, W. B., Liu, H., Sun, C., Drage, T. C., and Snape, C. E. (2014a). Perfor
mance of polyethyleneimine-silica adsorbent for post-combustion CO2 capture
in a bubbling fluidized bed. _Chem. Eng. J._ [251, 293–303. doi:10.1016/j.cej.2014.](http://dx.doi.org/10.1016/j.cej.2014.04.063)
[04.063](http://dx.doi.org/10.1016/j.cej.2014.04.063)
Zhang, W. B., Liu, H., Sun, C., Drage, T. C., and Snape, C. E. (2014b). Capturing

CO2 from ambient air using a polyethyleneimine-silica adsorbent in fluidized
beds. _Chem. Eng. Sci._ [116, 306–316. doi:10.1016/j.ces.2014.05.018](http://dx.doi.org/10.1016/j.ces.2014.05.018)
Zhang,X. P.,Zhang,X. C.,Dong,H. F.,Zhao,Z. J.,Zhang,S. J.,and Huang,Y. (2012).

Carbon capture with ionic liquids: overview and progress. _Energy Environ. Sci._
[5, 6668–6681. doi:10.1039/c2ee21152a](http://dx.doi.org/10.1039/c2ee21152a)
Zhang, Y. M., Li, B. Y., Williams, K., Gao, W. Y., and Ma, S. Q. (2013). A new

microporous carbon material synthesized via thermolysis of a porous aromatic
framework embedded with an extra carbon source for low-pressure CO2 uptake.
_Chem. Commun._ [49, 10269–10271. doi:10.1039/c3cc45252b](http://dx.doi.org/10.1039/c3cc45252b)
Zhao, C. W., Chen, X. P., Anthony, E. J., Jiang, X., Duan, L. B., Wu, Y., et al.

(2013). Capturing CO2 in flue gas from fossil fuel-fired power plants using dry
regenerable alkali metal-based sorbent. _Prog. Energy Combust. Sci._ 39, 515–534.
[doi:10.1016/j.pecs.2013.05.001](http://dx.doi.org/10.1016/j.pecs.2013.05.001)
Zhao, G. Y., Aziz, B., and Hedin, N. (2010). Carbon dioxide adsorption on meso
porous silica surfaces containing amine-like motifs. _Appl. Energy_ 87, 2907–2913.
[doi:10.1016/j.apenergy.2009.06.008](http://dx.doi.org/10.1016/j.apenergy.2009.06.008)
Zhao, M., Shi, J., Zhong, X., Tian, S., Blamey, J., Jiang, J., et al. (2014). A novel cal
cium looping absorbent incorporated with polymorphic spacers for hydrogen
production and CO2 capture. _Energy_ _Environ._ _Sci._ 7, 3291–3295. [doi:10.1039/](http://dx.doi.org/10.1039/C4EE01281J)
[C4EE01281J](http://dx.doi.org/10.1039/C4EE01281J)
Zhao,Y. F.,Zhao,L.,Yao,K. X.,Yang,Y.,Zhang,Q.,and Han,Y. (2012a). Novel porous

carbon materials with ultrahigh nitrogen contents for selective CO2 capture. _J._
_Mater. Chem._ [22, 19726–19731. doi:10.1039/c2jm33091a](http://dx.doi.org/10.1039/c2jm33091a)

Zhao, Y. F., Liu, X., Yao, K. X., Zhao, L., and Han, Y. (2012b). Superior capture of

CO2 achieved by introducing extra-framework cations into n-doped microporous carbon. _Chem. Mater._ [24, 4725–4734. doi:10.1021/cm303072n](http://dx.doi.org/10.1021/cm303072n)
Zhong, M. J., Natesakhawat, S., Baltrus, J. P., Luebke, D., Nulwala, H., Matyjaszewski,

K., et al. (2012). Copolymer-templated nitrogen-enriched porous nanocarbons
for CO2 capture. _Chem. Commun._ [48, 11516–11518. doi:10.1039/c2cc36652e](http://dx.doi.org/10.1039/c2cc36652e)
Zukal, A., Dominguez, I., Mayerova, J., and Cejka, J. (2009). Functionalization of

delaminated zeolite ITQ-6 for the adsorption of carbon dioxide. _Langmuir_ 25,
[10314–10321. doi:10.1021/la901156z](http://dx.doi.org/10.1021/la901156z)

Conflict of Interest Statement: The authors declare that the research was conducted
in the absence of any commercial or financial relationships that could be construed
as a potential conflict of interest.

_Received:_ _27_ _October_ _2014;_ _accepted:_ _12_ _February_ _2015;_ _published_ _online:_ _09_ _March_
_2015._
_Citation:_ _Sun_ _N, Tang_ _Z, Wei_ _W, Snape_ _CE_ _and_ _Sun_ _Y_ _(2015)_ _Solid_ _adsorbents_ _for_
_low-temperature CO2 capture with low-energy penalties leading to more effective inte-_
_grated solutions for power generation and industrial processes. Front. Energy Res._ _3_ _:9._
_[doi: 10.3389/fenrg.2015.00009](http://dx.doi.org/10.3389/fenrg.2015.00009)_
_This article was submitted to Carbon Capture, Storage, and Utilization, a section of the_
_journal Frontiers in Energy Research._
_Copyright © 2015 Sun, Tang, Wei, Snape_ _and Sun. This is an open-access article dis-_
_[tributed under the terms of the Creative Commons Attribution License (CC BY). The](http://creativecommons.org/licenses/by/4.0/)_
_use,_ _distribution_ _or_ _reproduction_ _in_ _other_ _forums_ _is_ _permitted,_ _provided_ _the_ _original_
_author(s)orlicensorarecreditedandthattheoriginalpublicationinthisjournaliscited,_
_in accordance with accepted academic practice. No use, distribution or reproduction is_
_permitted which does not comply with these terms._

본문 출처 PDF: PDF 보기 · 다른 PDF는 위 [PDF 업로드]로 올릴 수 있습니다.

활용가능성

이력 0건

아직 편집 이력이 없습니다. 저장할 때마다 이전 내용이 여기에 백업됩니다.