A study on boron removal for seawater desalination using the combination process of mineral cluster and RO membrane system

W1166811983 · 수집 2026-10-04 18:12:13

T10197 Membrane Separation Technologies

CoT 라벨링

라벨링 전

PDF 파일

업로드한 PDF 2026-10-04 19:28:57 PDF 보기

기본 정보

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

추가 정보 초록 본문

Environ. Eng. Res. 2015; 20(3): 285-289 pISSN 1226-1025
http://dx.doi.org/10.4491/eer.2014.0083 eISSN 2005-968X

# A study on boron removal for seawater desalination using the combination process of mineral cluster and RO membrane system

Bong-Yeon Cho † , Hye-Won Kim, Yee-Sook Shin

_Department of Civil and Environmental Engineering, Dongguk University, Seoul 100-715, Republic of Korea_

ABSTRACT
Complicated and expensive seawater desalination technology is a big challenge in boron removal process. Conventional seawater desalination
process of coagulation utilized for pre-treatment is difficult to remove boron. Boron can be removed more effectively in Reverse Osmosis (RO)
process than any other processes. In this study, a coagulant with the name Mineral Cluster was examined its boron removal ability. Boron
removal efficiency of Mineral Cluster depended on pH value and Mineral Cluster dosage. Desalination process combines the pre-treatment
process with Mineral cluster diluted at the ratio of 1:2500 and the RO membrane process. The original sea water could be desalinated to drinking
water quality, 1 mg/L, without any pH adjustments. Therefore, if the Mineral cluster is added without any other chemicals for adjusting pH,
the desalination process would be much safer, efficient and economical.

Keywords: Black Mica, Boron, Desalination, Illite, Mineral Cluster, RO membrane

1. Introduction

Boron is an indispensable component for human and animal taking
its major roles in human are for brain function and perception
temporary memory [1]. Also boron has protective characteristics
against prostate cancer [2]. In the desalination process for seawater,
boron is not easily removed because pH of about 6.5 should be
maintained by adding acid such as sulfuric acid in order to remove
scales such as calcium and silica. Therefore, the normal practice
is to convert seawater into fresh water by using the RO (Reverse
Osmosis) membrane of two stages, but such practice shows to
be inefficient due to high costs of maintenance [3].

Boron can become toxic when its amount is slightly greater
than the required amount. The common boron toxication symptoms
are nausea, vomiting, diarrhea, dermatitis and lethargy [4]. The
WHO guideline of standard boron concentration in drinking water
is 0.3 mg/L in 1990. It is difficult to comply to this standard due
to the available treatment technology reality. Hence, the guideline
of WHO was raised to 0.5 mg/L in 1998. The average concentration
of boron of freshwater of less than 0.1 mg/L and below 2 mg/L
in ground water become acceptable [5]. That of seawater of boron
at around 4.5 mg/L is acceptable [6]. The criteria of the amount

This is an Open Access article distributed under the terms
of the Creative Commons Attribution Non-Commercial License
(http://creativecommons. org/ licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any
medium, provided the original work is properly cited.

285

of boron in drinking water, established by WHO, is 0.5 mg/L. Every
country has distinct criteria based on WHO. For instance, the criteria
for United States, although it varies by each states, is approximately
0.6 mg/L, and for Europe, Japan and Korea are 1 mg/L; Australia
and Canada have relatively high standards which is about 4∼5
mg/L. If adequate amount of boron existing in seawater could be
removed during the pre-treatment process, the experiments would
only need to carry out the first stage of RO membrane to make
it drinkable. The pre-treatment process tested the efficiency of boron
removal by injecting the Mineral cluster, which acts as an adsorbent
that is extracted from natural mineral. Seawater desalination system
was reexamined based on the Lab scale experiment [7] using aqueous
solution and Pilot plant experiment using Sea water.

2. Materials and Methods

2.1. Experimental Apparatus

The general process of the seawater desalination is shown in Fig.
1. MF membrane was used in to remove the suspended solids
and the colloidal material the pre-treatment process; The FI (Fouling
index) was approximately 3.0 in this experiment. The removal

Received December 8, 2014 Accepted August 13, 2015

- Corresponding author
Email: bycho@dongguk.edu
Tel: +82-2-2260-3839 Fax: +82-2-2266-8753

B. Y. Cho _et al._

Fig. 1. The general processing system of the seawater desalination.

efficiency of boron was examined using RO membrane after using
the MF membrane in the pre-treatment process. The RO membrane
of Spiral type was used, and for the experimental condition for
RO membrane, the pressure of inlet water was 55~60 kgf/cm 2,
the Flux was 0.2~2 m 3 /m 2 ·day, and the recovery rate was 40%.
The boron concentration in the experiment was measured by using
the Curcumin method [8] from 'Standard Method (SMWW)'.

2.2. Condition of Original Seawater

The lab scale experiment used an aqueous solution; all bulk water
containing 4.5 mg/L of boron was adjusted to pH 7, 8, 9, 10 solutions
with sodium hydroxide (NaOH) and sulfuric acid (H2SO4)
respectively. The bulk solution was kept stirred rapidly for 2 minutes to encourage flocculation. The solution was stopped stirring
to settle down for 60 minutes at room temperature then filtered
with 0.45 μm membrane.

The pilot experiment of spiral wound RO system was used
to estimate the boron removal efficiency of Mineral cluster in
desalination process. Combining the efficiency of both Mineral
cluster and RO system enabled to calculate the final boron removal
efficiency.

The seawater samples used in this Pilot plant experiment were
attained from the Somuido coast in the western sea of Incheon
in South Korea. The electrical conductivity contained in the seawater was 41000 (㎲/cm), and the components of the seawater
are as listed in the following Table 1.

Table 1. Components of Seawater

Fig. 2. Process of mineral cluster production.

2.3. Materials (Mineral cluster)

The Mineral cluster in this experiment, a solution extracted from
the Black Mica, Illite using the following device of Fig.2 was used
as the coagulant of the pre-treatment process for removing boron.
In order to suppress the occurrence of the scale component occurring on the surface of RO membrane, the sulfuric acid was injected
into seawater while maintaining the pH of sea water 6.8±0.5.
The pilot plan experiment used Mineral cluster instead of Sulfuric
acid. The manufacturing process of the Mineral cluster is as the
following, and the components are as Table 2.

2.4. Experimental Method

2.4.1. Pre-treatment process using Mineral cluster
In order to investigate the optimal pH and the injection amount
of the Mineral cluster, the Jar test was carried out. Sodium
Hydroxide (NaOH) and Sulfuric acid (H2SO4) was used with the
pH adjusted to all 7, 8, 9 and 10. The Mineral cluster was diluted

Items Concentration Items Concentration
Conductivity (㎲/cm) 41,000 Na (mg/L) 8,800
Chloride (mg/L) 18,600 K (mg/L) 590
Tur. (NTU) 1.25 Cl (mg/L) 20700
pH 7.8 SO4 (mg/L) 1400
T-S (mg/L) 34,000 Calcium (mg/L) 400
Magnesium 1310 Boron (mg/L) 4.5

Table 2. Main Components of Mineral Cluster Solution

Component Concentration (mg/L) Percentage (%) Component Concentration (mg/L) Percentage (%)
Al 530.0 35 Ti 12.0 0.8
Fe 373.4 26 Mn 11.5 0.8
Mg 345.0 23 Zn 6.92 0.5
K 115.0 8 Se 6.47 0.5
Ca 57.7 4 P 2.64 0.2
Si 34.2 2 V 1.07 0.1
Na 27.1 1.8 etc. 3.3 0.2

286

according to the ratios of 1:100, 1:500, 1:1000 and 1:2500 into
the aqueous solution and seawater of 250 mL, and the boron concentrations according to each pH condition were measured.

2.4.2. Boron removal using RO membrane
The experiment of the RO membrane was divided into two types.
The first experiment is to verify how much boron would be removed
when using solely RO membrane. The second experiment combines
RO and Mineral cluster to treat RO membrane after using the
Mineral cluster in the pre-treatment process. Cohesion, absorption,
oxidation and filtration, etc. are the widely practiced pre-treatment
process of RO membrane, but this experiment treated with MF
after injecting Mineral cluster.

3. Results and Discussion

3.1. Boron Removal Rate according to pH

The experiment was carried out to obtain the optimum value of
pH condition during the boron removal process. Boron is completely dissociated with B(OH) 4- at pH higher than 11 and is formed
as H3BO3 at pH lower than 7 [9]. The samples of the western
sea of Incheon containing boron concentration of 4.5 mg /L were
adjusted to pH of 7, 8, 9, and 10 with 1: 100 of Mineral cluster.
Boron removal efficiency showed that it increased with pH value
between 8 and 9. The highest efficiency of boron removal is 40.0%
and 2.7 mg/L at pH 9 and boron removal is 31.3% and 3.1 mg/L
at pH 8 in Fig 3. 28.9% (3.2 mg/L) and 15.6% (3.8 mg/L) of boron
was removed at pH 10 and 7 respectively.

Boron removal mechanism can be explained with the coagulation and adsorption mechanism of Alum and Iron. Alum coagulant is successfully removed at the pH range of 5.5 and 8 and
Iron does best at pH range of 5.0 and 11.0 [10]. Mineral cluster
solution contains a variety of minerals especially Alum (530 mg/L)
and Iron (373 mg/L) in high extent amount, which took major
roles in the coagulation process. Therefore the optimum efficiency
can be deduced to around pH 9 in Mineral cluster.

According to major interactions and forces of atoms and molecules, boron adsorption mechanism can be inferred from those
types of molecular and atomic interactions and bonding, such
as hydrophilic, hydrophobic and electrostatic interaction but also
hydrogen bonding [11]. Hydrogen bonding and hydrophobic interaction can be major roles in the adsorption mechanism of boron
which can be formed with boric acid and borates ions from the
physicochemical natures of boron particle surfaces. All the particle
surfaces of boron have the suitable functional groups enabling
hydrogen bonding with boric acid or borate ions which can enhance
the adsorption process in well-adjusted aqueous media of pH
condition. The equal number of boric acid and borates ions can
be formed at the well-adjusted aqueous pH 9 solution which promoted increased hydrogen bonding and electrostatic attraction
but also hydrophobic interactions. The relations between molecules containing non polar group and water can be described
with hydrophobic interaction in aqueous solution. Thus, the adsorption was reduced due to the lack of hydrophobic interaction
at higher pH than 9, but also at the lower pH than 9 the lack

287

Environmental Engineering Research 20(3) 285-289

Fig. 3. Change of boron concentration at difference pH.

of electrostatic force makes the adsorption decrease in substantial
extent. Boron removal efficiency clearly improved with increasing
Mineral cluster dosage and the optimum pH condition was clarified
with pH 9 in the above experiment.

3.2. Optimal Injection Amount of Mineral Cluster

Fig. 4 shows the experimental results of boron removal efficiency
according to the amount of Mineral cluster in pH 9 as presented
in the above experimental condition. As a result, the boron concentrations were 4.5 mg/L in pH 9 were 4.5 mg/L, 4.3 mg/L, 4.0 mg/L,
and 3.7 mg/L when the Mineral cluster was diluted to 100 times,
500 times, 1000 times and 2500 times respectively.
Of the four dilution ratios 1:100, 1:500, 1:1000 and 1:2500,
the ratio 1:2500 showed the greatest amount of removal. Because
the Mineral cluster itself is a strong acid its pH is lowers when
great amounts are injected into the sea water with pH of 7 and
8. In this experiment the boron removal efficiency by Mineral
cluster was performed at pH 9. As the quantity of the Mineral
cluster increased the removal efficiency decreased and vice versadue to its acidic nature. Table 2 represents the major components
of the Mineral Cluster which are Ca, Fe, Mg, Al, Na, K and Si.
Of the components Al is the most with the percentage of 35.3%,
and Fe is the second most with 23%. Al and Fe are normally
used as coagulants and adsorbents [12]; Aluminum sulfate, ferrous
sulfate and ferric sulfate are the commonly used materials containing Al and Fe. Clay minerals are normally used as adsorbents
since their porous structure [13, 14]. Therefore, Mineral cluster
can remove boron via adsorbing and aggregating.

Fig. 4. Change of Boron concentration according to dilution ratio of
mineral cluster at pH 9.

B. Y. Cho _et al._

3.3. Boron Removal Efficiency by RO Membrane System

3.3.1. Boron removal via RO membrane
The purpose of this experiment is to investigate the removal efficiency of boron contained in seawater through RO membrane

[15]. Fig. 5 shows the measurements of the boron concentration
after processing the original seawater collected at Somuido in
Incheon. The initial concentration of boron in sea water was 4.5
mg/L. By adjusting the pH of the sea water to pH of 7, 8, 9, 10
the boron concentration changed to 1.85 mg/L (removal rate 59%),
1.53 mg/L(66%), 0.9 mg/L(80%) and 0.5 mg/L(89%), respectively.
When the pH of sea water is above 9, boron could be removed
up to 1.0 mg/L which is near drinking water quality. In order
to solely remove boron, an additional process to pH adjustment
is required.

Fig. 5. Removal rate of Boron according to pH variation.

3.3.2. Efficiency of the combination process of mineral cluster
and RO membrane system
This experiment examined the boron removal efficiency by removing certain amount of boron through Mineral cluster injection
in the pre-treatment process and removing the rest through RO
membrane in Fig. 6. The removal of boron in seawater at pH
7, 8, 9, and 10 were 0.96 mg/L (removal rate 74%), 0.65 mg/L
(82%), 0.3 mg/L (92%), and 0.1 mg/L (97%) respectively. As shown
the above the removal rate was above 90% when pH was adjusted
to 9 or higher. When solely processed through RO membrane,
the boron concentration was 1.85 mg/L at pH 7. However the
concentration turned out to be 0.90 mg/L when the Mineral cluster

Fig.6. Effect of Boron removal by pre-treatment process and RO
membrane.

288

was injected at the ratio 1:2500. Such value does not concord
with the WHO criteria that is 0.5 mg/L but it comply to Korea’s
standard, 1.0 mg/L. pH is maintained as a weak acid to prevent
the scale in the seawater desalination process. Simple Mineral
cluster injection diluted at 1: 2500 is required to lower the pH
condition. Therefore, if the desalination process combines Mineral
cluster injection in the pre-treatment process and the RO membrane, the whole process would proceed much efficiently and
economically.

4. Conclusions

The following results were attained when the process combined
Mineral cluster in the pre-treatment process and RO membrane
process. Boron removal is depended largely on pH condition and
it is difficult to remove by common water treatment method due
to its different chemical formation. The solution of pH 9 is best
condition for boron removal by Mineral cluster coagulant. Boron
can be eliminated until 80% with 1:2500 Mineral clusters at this
pH value. The original sea water could be desalinated to drinking
water quality, 1 mg/L, without any pH adjustments if the desalination process combines the pre-treatment process with
Mineral cluster diluted at the ratio of 1:2500 and the RO membrane
process. The desalination process would be much safer, efficient
and economical if the Mineral cluster was added without any
other chemicals for adjusting pH. Thus the Mineral cluster injection
process was well suited to the desalination system.

References

1. Penland JG, Dietary boron, brain function, and cognitive

performance. _Environ. health perspect_ . 1994;102:65.
2. Bakirdere S, Örenay S, Korkmaz M. Effect of Boron on Human

Health. _TOMPJ_, 2010;3:54-59.
3. Redondo J, Busch M, De Witte JP. Boron removal from seawater

using FILMTECTM high rejection SWRO _membranes._
_Desalination_ 2003;156:229-238.
4. Linden CH, et al. Acute ingestions of boric acid. _Clin. Toxicol._

1986;24:69-279.
5. Tu KL, Nghiem LD, Chivas AR. Boron removal by reverse

osmosis membranes in seawater desalination applications. _Sep._
_Purif. Technol._ 2010;75:87-101.
6. WHO. Guidelines for drinking-water quality. 3rd ed. Geneva:

World Health Organization; 2004. p. 27.
7. Hong Hong V, Bong-Yeon C. A study on Boron Removal by

Mineral Cluster Coagulant for Seawater Desalination
Application. _Env. Eng. Res._ 2011;16:227-230.
8. Clescerl LS, Greenberg AE, Eaton AD. Standard Methods for

Examination of Water & Wastewater. 20th ed. Washington,
DC: Amer Public Health Assn; 1999.
9. Hilal N, Kim GJ, Somerfield C. Boron removal from saline

water: A comprehensive review. _Desalination_ 2011;273:23-35.
10. Department of the army. Chapter 8: Coagulants, Polyelectrolytes,
and Coagulant Aids. In: Engineering Manual. Washington, DC:

U.S. Army Corps of Engineers; 2002.
11. Liu H, et al. Boron adsorption by composite magnetic particles.
_Chem. Eng. J._ 2009;151:235-240.
12. Bratby J. Coagulation and flocculation in water and wastewater
treatment. Seattle: IWA. Publishing London; 2006.
13. Cho HS, Kim EY, Jeong GY. Surface Chemical Properties of
the Youngdong Illite Ore: The pH of Zero Proton Charge and

289

Environmental Engineering Research 20(3) 285-289

Surface Site Density. _J. Miner. Soc. Korea_ 2001;14:12.
14. Cho HG, et al. Phosphate Adsorption of Youngdong Illite, Korea.
_J. Miner. Soc. Korea_ 2007;20:327-337.
15. Bernstein R, Belfer S, Freger V. Toward Improved Boron
Removal in RO by Membrane Modification: Feasibility and
Challenges. _Environ. Sci. Technol._ 2011;45:3613-3620.

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.