KR101030192B1 - Method of removing boron in seawater adopting crystallization process - Google Patents

Method of removing boron in seawater adopting crystallization process Download PDF

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KR101030192B1
KR101030192B1 KR1020100067495A KR20100067495A KR101030192B1 KR 101030192 B1 KR101030192 B1 KR 101030192B1 KR 1020100067495 A KR1020100067495 A KR 1020100067495A KR 20100067495 A KR20100067495 A KR 20100067495A KR 101030192 B1 KR101030192 B1 KR 101030192B1
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reverse osmosis
boron
membrane
seawater
water
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KR1020100067495A
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Korean (ko)
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한인섭
이준희
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서울시립대학교 산학협력단
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/26—Treatment of water, waste water, or sewage by extraction
    • C02F1/265—Desalination
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/08—Seawater, e.g. for desalination
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/06—Controlling or monitoring parameters in water treatment pH

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Organic Chemistry (AREA)
  • Nanotechnology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

PURPOSE: A method for eliminating boron from seawater is provided to cost-effectively implement boron using a reverse osmosis process without an expensive ion-exchanging resin. CONSTITUTION: A reverse osmosis process is implemented with respect to seawater using a front reverse osmosis film(1). The pH of concentrated water, which does not permeate through the front osmosis film, is adjusted in order to implement a pre-crystallization process and a filtering process. In the filtering process, a reverse osmosis process is implemented with respect to filtering water under the filtering process using a rear reverse osmosis film(2). Permeated water through the front and the rear reverse osmosis films is collected.

Description

결정화 공정을 채용한 해수 내 보론의 제거방법 {Method of Removing Boron in Seawater Adopting Crystallization Process}Method of Removing Boron in Seawater Adopting Crystallization Process

본 발명은 해수 내 보론(B)의 제거방법 및 이를 포함하는 해수담수화 방법에 관한 것이다.
The present invention relates to a method for removing boron (B) in seawater and a seawater desalination method including the same.

최근 인간이 사용할 수 있는 담수량의 부족으로 인하여 해수담수화 시설이 증가하고 있다.Recently, desalination facilities have increased due to the lack of freshwater available to humans.

과거의 해수담수화 시설은 Thermal 방식을 이용한 MED(Multi-Effect Distillate), MSF(Multi Stage Flash Distillate) 등을 사용하였지만 최근에는 Membrane 성능의 발달, Membrane의 가격 하락(10년 전에 비해 절반 가격), 에너지 효율성을 고려한 공정, 운영비 관리, 운전의 편이성 등으로 인하여 SWRO(seawater reverse osmosis) 막을 이용한 해수담수화 시설이 증가하고 있다.In the past, the seawater desalination plant used thermal-method multi-effect distillate (MED) and multi-stage flash distillate (MSF), but recently, the development of membrane performance, the price of membrane (half the price of 10 years ago), energy Due to efficiency-related processes, operating cost management, and ease of operation, seawater desalination facilities using SWRO (seawater reverse osmosis) membranes are increasing.

해수에는 70여종 이상의 원소가 포함되어 있는데 주요 성분은 Na+, Mg2 +, Ca2+, K+, Sr2 +, Cl-, SO4 2 -, Br- 등으로서 SWRO 막에 의해 99.5% 이상 제거되며, 또한 유기물 및 세균도 충분히 제거가 된다. 이러한 SWRO 막에 의해 생산된 투과수의 수질은 우리나라의 먹는 물 수질기준에 적합하다고 보고된다.There seawater contains more than 70 kinds of the main component elements Na +, Mg 2 +, Ca 2+, K +, Sr 2 +, Cl -, SO 4 2 -, Br - such as at least 99.5% by SWRO membrane It is also removed, and organic matter and bacteria are also sufficiently removed. It is reported that the water quality of the permeated water produced by the SWRO membrane meets the drinking water quality standards in Korea.

종래 SWRO 막을 이용한 해수담수화의 주요 과제는 투과수의 회수율로, SWRO 막 1단 시설의 1cycle 운전시 회수율은 유입수의 35~40% 정도로 낮아 회수율을 증가시키기 위하여 다단식 SWRO 시스템을 적용하고 있다. The main task of seawater desalination using SWRO membrane is the recovery rate of permeated water, and the multi-stage SWRO system is applied to increase the recovery rate during the 1 cycle operation of the SWRO membrane 1st stage as low as 35-40% of the influent.

그러나, 다단 SWRO 시스템은 회수율 증가, 농축수 압력 재사용, 농축 수량의 감소 등으로 경제적으로 큰 이점을 가지지만 보론(B) 농도가 먹는물 수질 기준(한국) 1.0mg/L을 초과한다는 문제가 있다. However, the multi-stage SWRO system has economic advantages such as increased recovery rate, reuse of concentrated water pressure, and reduced concentration of water, but there is a problem that boron (B) concentration exceeds 1.0mg / L of drinking water quality standard (Korea). .

보론이 음용수에 과다하게 존재하면 동식물과 인간에게 다양한 질병을 유발시킨다. 장단기 구강노출 동물실험에서 rat, mice, dog에게 보론이 함유된 사료 또는 물을 투여한 결과 고환 장애가 나타났고 인간이 장기간 섭취를 할 경우 인체의 소화기나 신경계통에 장애를 일으키는 물질로 알려져 있다. Excessive boron in drinking water causes various diseases in animals and plants and humans. In the short and long term oral exposure animal experiments, rats, mice, and dogs were treated with boron-containing feed or water, and testicular disorders were observed.

기존의 해수나 폐수로부터 보론을 제거하는 방법에는 용매추출법, 공침법, 이온교환법, 전기투석, 전기응집 등이 있다. 이 중 가장 효과적인 방법으로 글루카아민 작용기를 함유하고 있는 아민형 음이온교환 킬레이트수지를 사용하는 이온교환법을 꼽을 수 있지만 이는 경제성의 측면에서 대용량을 처리해야 하는 해수담수화 시스템에 적용하기는 무리가 있다.
Conventional methods for removing boron from seawater or wastewater include solvent extraction, coprecipitation, ion exchange, electrodialysis and electrocoagulation. The most effective method is ion exchange using an amine type anion exchange chelate resin containing a glucaamine functional group, but it is difficult to apply it to a seawater desalination system that requires a large capacity in terms of economy.

본 발명의 목적은 경제적이며, 효율적으로 보론을 제거할 수 있는 보론 제거방법을 제공하는 것이다.It is an object of the present invention to provide a boron removal method that can remove boron economically and efficiently.

또한, 본 발명의 다른 목적은 상기 방법을 이용하는 해수담수화 방법을 제공하는 것이다.
Another object of the present invention is to provide a seawater desalination method using the above method.

상기 목적을 달성하기 위하여,In order to achieve the above object,

본 발명의 일 측면에 의하면, According to one aspect of the invention,

i) 해수에 전단 역삼투막을 이용하여 역삼투 공정을 수행하는 단계;i) performing a reverse osmosis process using a shear reverse osmosis membrane in seawater;

ii) 단계 i)에서 역삼투막을 통과하지 않은 농축수의 pH를 조절하여 전결정 공정 및 여과공정을 수행하는 단계; 및ii) adjusting the pH of the concentrated water that has not passed through the reverse osmosis membrane in step i) to perform a precrystallization process and a filtration process; And

iii) 단계 ii)의 여과수에 후단 역삼투막을 이용하여 역삼투 공정을 수행하는 단계를 포함하는 해수 내 보론의 제거방법을 제시할 수 있다.
iii) a method of removing boron in seawater, including performing a reverse osmosis process using a reverse reverse osmosis membrane in the filtered water of step ii).

또한, 본 발명의 다른 일 측면에 의하면,In addition, according to another aspect of the present invention,

상기 해수 내 보론의 제거방법의 단계 i) 내지 iii) 후에 전단 역삼투막을 통과한 투과수와 후단 역삼투막을 통과한 투과수를 합하는 단계를 더 포함함으로써, 후처리 공정 중 pH 조절공정을 생략할 수 있는 해수 담수화 방법을 제시할 수 있다.
After the steps i) to iii) of the method of removing boron in the seawater, the method may further include the step of combining the permeate passed through the reverse reverse osmosis membrane and the permeate passed through the reverse reverse osmosis membrane, thereby eliminating the pH adjustment process during the post-treatment process. Can suggest a seawater desalination method.

본 발명의 보론 제거방법은 값비싼 이온교환 수지를 사용하지 않아도 보론 제거율이 높고, 결정화 공정으로 인한 역삼투막의 운전 전력이 감소되어 경제적이므로, 해수 담수화 방법에 유용하게 사용될 수 있다.
The boron removal method of the present invention has a high boron removal rate even without using an expensive ion exchange resin, and the operating power of the reverse osmosis membrane due to the crystallization process is economical, and thus can be usefully used for the seawater desalination method.

도 1 및 도 2는 본 발명의 결정화 단계를 채용한 2단 역삼투 공정을 포함하는, 해수 내 보론 제거방법의 흐름 및 이에 사용되는 설비를 나타내는 개략도이다. 1 and 2 are schematic diagrams showing the flow of boron removal method in seawater and the equipment used therein, including a two-stage reverse osmosis process employing the crystallization step of the present invention.

이하, 본 발명을 좀더 상세하게 설명한다.
Hereinafter, the present invention will be described in more detail.

일반적으로 해수중에 존재하는 보론 농도는 4~5mg/L, 염소이온 농도의 약 0.00023배이다. In general, the concentration of boron in seawater is 4-5 mg / L, about 0.00023 times the concentration of chlorine ion.

수용액에 포함된 보론은 응집, 침전, 여과 등 일반적인 정수처리 방법으로는 제거할 수 없기 때문에 별도의 처리장치가 필요하다. 이온교환과 역삼투압 공정을 통해 상당량이 제거될 수 있는데 염분제거율이 99.5%정도인 역삼투막에 의해 40~80% 정도 제거된다. Since boron contained in the aqueous solution cannot be removed by general water treatment methods such as flocculation, sedimentation and filtration, a separate treatment device is required. Significant amounts can be removed through ion exchange and reverse osmosis processes. About 40-80% of the desalination rate is reversed by reverse osmosis membranes with 99.5%.

해수 내 보론의 이온화 평형식은 다음과 같다. The ionization equilibrium of boron in seawater is

B(OH)3(aq) + H2O ↔ H+(aq) + B(OH)4-(aq) pKa = 9.14 (25℃)B (OH) 3 (aq) + H 2 O ↔ H + (aq) + B (OH) 4- (aq) pKa = 9.14 (25 ° C)

역삼투압법을 적용시 pH가 8보다 낮을 때는 boric acid (B(OH)3)의 형태로 많이 존재하여 낮은 제거율을 보이지만 높은 pH일 경우 전하의 생성 및 분자 크기의 증가를 가진 borate ion (B(OH)4 -)의 증가로 보론의 제거율이 높게 나타난다.When the reverse osmosis method is applied, when the pH is lower than 8, it is present in the form of boric acid (B (OH) 3 ) and shows low removal rate, but at high pH, borate ion (B ( OH) 4 - are higher removal rate of boron to the increase in).

보론은 pH에 따라서 존재형태가 변화하는데 pH 9.2 이상에서 B(OH)4-이 B(OH)3보다 많이 분포하여 막에 의한 제거율이 높아진다. 따라서 보론이 B(OH)4- 이온 형태가 되는 염기성 영역에서의 역삼투막 운전이 보론을 제거하기 위한 가장 큰 관건이다. Boron changes its presence depending on pH, and more than B (OH) 4- is distributed more than B (OH) 3 at pH 9.2 or higher. Therefore, reverse osmosis membrane operation in the basic region where boron is in the form of B (OH) 4- ion is the key to removing boron.

그러나 농축수(Brine)를 원수로 사용하는 2단째 SWRO 시스템에서는 pH 증가가 어려운데, 이는 1단에서 배출된 농축수에 녹아 있는 Si2 +, Ca2 +, Mg2 + 등의 농도가 높아 pH 증가로 인해 증가된 HCO3 -, CO3 2 - 등과 결합하여 Scale을 형성하기 때문이다. Scale은 유입수 중에 용해되어 있는 Ca2+, Mg2+ 등의 2가 양이온과 HCO3 -, CO3 2-등의 음이온이 결합되어 CaCO3, MgCO3, CaSO4 같은 침전물을 형성하여 막 표면에 생성되는 것이다. However, it is difficult to increase the pH in the second stage SWRO system using brine as raw water, which is due to the high concentration of Si 2 + , Ca 2 + and Mg 2 + dissolved in the concentrated water discharged from the first stage. This is because HCO 3 - and CO 3 2 -are combined to form scale. The scale combines divalent cations such as Ca 2+ and Mg 2+ dissolved in the influent and anions such as HCO 3 - and CO 3 2- to provide CaCO 3 , MgCO 3 and CaSO 4. It forms a precipitate and is produced on the membrane surface.

이러한 Scale을 방지하기 위해서 종전에는 pH를 5 ~ 6.5로 조절(CO3 2-, HCO3 -, H2CO3의 전탄산 비를 조정)하거나, SHMP (Sodium hexametaphosphate)등의 Antiscalant를 투여하거나, 여과수의 회수율을 감소시키는 방법이 연구되어져 왔다. Such Previously, adjusting the pH to prevent Scale to 5 ~ 6.5 (CO 3 2-, HCO 3 -, adjusting the ratio of the former acid H 2 CO 3), or administration of Antiscalant such as SHMP (Sodium hexametaphosphate), or filtered water The method of reducing the recovery rate of has been studied.

본 발명의 핵심은, 1단 역삼투 공정을 수행한 농축수의 2단 SWRO 막 투과 전 pH를 일부러 증가시켜 Scale을 유발, 여과를 통해 제거하고 2단 역삼투를 수행하여 높아진 pH로 인해 증가된 이온 형태의 보론을 효율적으로 제거할 수 있다는 것에 있다. The key point of the present invention is to intentionally increase the pH before the two-stage SWRO membrane permeation of the concentrated water that has been subjected to the one-stage reverse osmosis process to induce scale, remove it through filtration, and then increase the pH due to the two-stage reverse osmosis. The boron in ionic form can be removed efficiently.

본 발명의 방법은 The method of the present invention

i) 해수에 전단 역삼투막을 이용하여 역삼투 공정을 수행하는 단계;i) performing a reverse osmosis process using a shear reverse osmosis membrane in seawater;

ii) 단계 i)에서 역삼투막을 통과하지 않은 농축수의 pH를 조절하여 결정화 공정 및 여과 공정을 수행하는 단계; 및ii) performing a crystallization process and a filtration process by adjusting the pH of the concentrated water that has not passed through the reverse osmosis membrane in step i); And

iii) 단계 ii)의 여과수에 후단 역삼투막을 이용하여 역삼투 공정을 수행하는 단계를 포함할 수 있다.iii) using the reverse reverse osmosis membrane in the filtered water of step ii) may comprise performing a reverse osmosis process.

본 발명에 사용하는 역삼투막은 용매 즉, 물은 통과하고 식염 등의 용질은 통과하지 않는 반투막을 사용하여 삼투압보다 큰 압력을 가할시 용매와 용질이 분리되는 특징을 가지는데, 이 역삼투막을 사용하여 무기성 이온류, 저분자 유기물 등을 제거할 수 있다. 분리대상 범위는 분획분자량으로 350Da 이하이고, 조작압력은 40~100bar 까지 가능하다.The reverse osmosis membrane used in the present invention has a characteristic that the solvent and the solute are separated when a pressure greater than osmotic pressure is applied by using a semi-permeable membrane that passes through a solvent, that is, water, and solutes such as salt do not pass. Sex ions, low molecular organics, etc. can be removed. The range to be separated is fraction molecular weight of 350 Da or less, and the operating pressure can be up to 40 ~ 100bar.

상기 결정화(crystallization) 및 여과 공정에서는 농축수의 pH를 9.0 ~ 10.5 영역으로 조절함에 의해 Ca2 +, Mg2 + 등의 2가 양이온과 HCO3 -, CO3 2 -등의 음이온이 결합하여 결정체가 생성되고, 생성된 결정체는 침전되어서 상등액과 분리된다.By the crystallization (crystallization), and the filtering process to adjust the pH of the concentrated water to 9.0 ~ 10.5 area Ca 2 +, Mg 2 +, such as divalent cations and HCO 3 in the -, CO 3 2 - and combine anions such as crystals Is produced, and the resulting crystals are precipitated and separated from the supernatant.

그러나, 침전되지 못하고 수중에 부유하고 있는 결정체는 역삼투막(SWRO막)을 보호하기 위해서 MF (microfiltration) 여과막을 이용하여 걸러낸다. However, crystals that are not precipitated and suspended in water are filtered using a MF (microfiltration) filtration membrane to protect the reverse osmosis membrane (SWRO membrane).

후단 역삼투막에 유입되는 전단 역삼투 과정 수행 후의 농축수가 pH 9.0 미만일 경우 boric acid가 borate ion으로의 형태전환이 어려워 보론의 제거율이 낮고 pH 10.5를 초과할 경우 수중의 Na+, K+, Ca2+ ion의 농도가 높아져서 SWRO막을 통해 투과되는 투과수 내의 Na+, K+, Ca2 + ion의 농도가 높아져 수질에 악역향을 미치고, pH 조절제의 투입량이 증가하므로 경제적으로도 부적합하다. When the concentrated water after the reverse reverse osmosis process flowing into the rear reverse osmosis membrane is less than pH 9.0, boric acid is difficult to change form to borate ion, so that the removal rate of boron is low, and when pH exceeds 10.5, Na + , K + , Ca 2+ in water high and the concentration of the ion increases the concentration of the permeation Na +, K +, Ca 2 + ion in the number that is transmitted through a film having a villain SWRO effort to water quality, it is economically not suitable because the amount of the pH adjusting agent increases.

pH 조절은 Ca(OH)2, NaOH 또는 KOH와 같은 pH 조절제를 농축수에 첨가함으로써 조절될 수 있다. 이들은 처리수의 부피 변화를 최소화 하기 위하여 1~3N 농도의 용액으로 조제하여 사용될 수 있는데, 상기 화합물 중 Ca(OH)2를 사용하여 pH를 9.6 으로 조정하여 실험했을 때 가장 높은 보론 제거율을 나타내었고, 한국 뿐만 아니라 WHO 수질기준도 만족하는 것을 확인하였다. pH control can be adjusted by adding a pH adjuster such as Ca (OH) 2 , NaOH or KOH to the concentrated water. These can be used to prepare a solution of 1 ~ 3N concentration in order to minimize the volume change of the treated water, the highest boron removal rate when tested by adjusting the pH to 9.6 using Ca (OH) 2 of the compound In addition, Korea also confirmed that the water quality standards of WHO were satisfied.

한편, 결정화의 효율을 높이기 위하여 CO2를 나노버블링 장치로 공급해 준다. 그 이유는 CO2가 용해되면서 물 속에 있는 양이온들과 결합하여 결정체를 구성하기 때문이다. 상기 결정체로는 CaCO3, MgCO3 등이 주를 이룬다.Meanwhile, in order to increase the efficiency of crystallization, CO 2 is supplied to the nanobubbling device. This is because CO 2 dissolves and combines with cations in water to form crystals. As the crystals, CaCO 3 , MgCO 3 and the like predominantly.

SWRO막 유입 전 MF 여과 공정은 생성된 Scale 및 여러 부유물질을 걸러내는 과정으로서, 동일한 혹은 다른 기공 크기를 가지는 필터를 이용하여 1회 이상 수행될 수 있다. 상기 여과막으로는 polyethersulfone, celluloe acetate, polyamide와 같은 소재의 0.1 내지 100 ㎛ 기공 크기의 시판되는 막을 이용할 수 있으나, 이에 제한되는 것은 아니다. The MF filtration process before the SWRO membrane is introduced is a process of filtering the generated scale and various suspended substances, and may be performed one or more times using a filter having the same or different pore size. The filtration membrane may be a commercially available membrane having a pore size of 0.1 to 100 μm, such as polyethersulfone, celluloe acetate, and polyamide, but is not limited thereto.

본 발명의 보론 제거방법은 Boron removal method of the present invention

단계 i) 내지 iii) 후에 전단 역삼투막을 통과한 투과수와 후단 역삼투막을 통과한 투과수를 합하는 단계(Blending)를 더 포함하는, 해수 담수화 방법에 이용될 수 있다.After step i) to iii), further comprising the step of combining the permeated water passed through the front end reverse osmosis membrane (Blending), can be used in the seawater desalination method.

이 경우, 담수로 이용하기 위하여 추가로 투과수의 pH를 조절할 필요가 없거나 적어져 유용하다.In this case, there is no need to adjust the pH of the permeate additionally or less to use it as fresh water.

즉, 전단(1단) 역삼투막을 통과한 투과수는 pH가 5~6 정도이고, 후단(2단) 역삼투막을 투과한 투과수는 pH가 8~9가 되므로, 이들을 합할 경우, 중성 pH에 가깝게 되어 pH 조절에 필요한 조작이 용이하고 경제적이다. That is, the permeated water that passed through the front (first stage) reverse osmosis membrane has a pH of about 5 to 6, and the permeated water that has passed through the rear stage (two stage) reverse osmosis membrane has a pH of 8 to 9. It is easy to operate and economical for pH control.

또한, 결정화 공정에서 발생된 결정의 제거로 후단 역삼투막의 운전 전력이 감소되어 전력을 절약할 수 있는 이점도 있다.
In addition, the removal of the crystals generated in the crystallization process has the advantage that the operating power of the reverse reverse osmosis membrane is reduced to save power.

하기 실시예에 의하여 본원발명을 보다 상세하게 설명하지만 하기 실시예는 발명을 설명하기 위한 것일 뿐 이에 의해 발명의 범위가 제한되는 것으로 해석될 수 없다.
The present invention will be described in more detail with reference to the following examples, but the following examples are only intended to illustrate the invention and thus should not be construed as limiting the scope of the invention.

실시예 1: Example 1:

1-1: 실험장치1-1: Experiment apparatus

본 실험에 사용된 결정화 및 역삼투막 장치는 고압펌프, 나노버블링장치, SWRO 막 등으로 구성되어 있고 장치의 개략도는 도 1과 같다. 고압 펌프는 최대 100 bar까지 출력 가능한 펌프를 사용하였고, 나노버블링 장치는 CO2를 사용하여 나노 사이즈의 버블을 발생시켜 주입하였다. SWRO 막은 voltron사의 SW21-4040이고 막여과 면적은 7.4m2이다. 사용한 SWRO 막의 특성은 표 1에 나타내었다. The crystallization and reverse osmosis membrane device used in this experiment is composed of a high pressure pump, nanobubbling device, SWRO membrane and the like, the schematic diagram of the device is shown in FIG. The high pressure pump used a pump capable of outputting up to 100 bar, and the nanobubbling device was injected by generating nano-sized bubbles using CO 2 . SWRO membrane is voltron SW21-4040 and membrane filtration area is 7.4m 2 . The characteristics of the SWRO membrane used are shown in Table 1.

ItemsItems R/OR / O SW21-4040SW21-4040 UsageUsage Sea WaterSea water TypeType SpiralSpiral MaterialMaterial PolyamidePolyamide Size(Element)Size (Element) ?3.9inch x L40inch 3.9inch x L40inch Active Membrane Area (m2)Active Membrane Area (m 2 ) 7.47.4 Stable Rejection Rate (%)Stable Rejection Rate (%) 99.599.5 Minimum Rejection Rate (%)Minimum Rejection Rate (%) 99.299.2 Max. Working Pressure (bar)Max. Working Pressure (bar) 6969 Max. Feedwater Flow (m3/h)Max. Feedwater Flow (m 3 / h) 3.63.6 Max. Feedwater Temperature (℃)Max. Feedwater Temperature (℃) 4545 Max. Feedwater SDIMax. Feedwater SDI 55 Residual chlorine Concentration of Feedwater (ppm)Residual chlorine Concentration of Feedwater (ppm) <0.1<0.1 pH Range of Feedwater during Continuous OperationpH Range of Feedwater during Continuous Operation 3~113 ~ 11 pH Range of Feedwater during Chemical CleaningpH Range of Feedwater during Chemical Cleaning 2~122-12 Max. Pressure Drop of Single Membrane Element (Mpa)Max. Pressure Drop of Single Membrane Element (Mpa) 0.10.1 (Test Conditions)(Test Conditions) Testing Pressure (Mpa)Testing Pressure (Mpa) 5.55.5 Temperature of Testing Solution (NaCl, ppm)Temperature of Testing Solution (NaCl, ppm) 3280032800 Temperature of Testing Solution (℃)Temperature of Testing Solution (℃) 2525 pH Value of Testing SolutionpH Value of Testing Solution 7.57.5 Recovery Rate of Single Membrane Element (%)Recovery Rate of Single Membrane Element (%) 88

일반적으로 보론을 제거하기 위해서 2-pass 시스템에 SWRO 막을 사용하지만 본 연구에서는 2-stage 시스템을 적용하여 보론의 제거뿐만 아니라 회수율의 증대도 도모하였다. Generally, SWRO membrane is used in the 2-pass system to remove boron, but in this study, the 2-stage system was applied to not only remove boron but also increase the recovery rate.

기존의 2-stage SWRO system은 1 stage의 농축수를 2 stage의 SWRO 막으로 별다른 처리없이 유입시키지만 본 발명은 2 stage SWRO 막에 유입되기 전에 결정화 공정을 삽입한 것에 특징이 있다. The existing two-stage SWRO system introduces one stage of concentrated water into the two stage SWRO membrane without any treatment, but the present invention is characterized by inserting a crystallization process before the two stage SWRO membrane.

실험장치의 운전은 1-stage의 SWRO 막의 120L의 농축수를 나노버블링 장치에 일정하게 유입시켜 CO2의 용해를 고려하여 운전하였다.
The operation of the experimental apparatus was operated in consideration of the dissolution of CO 2 by constantly introducing 120 L of concentrated water of the 1-stage SWRO membrane into the nanobubbling apparatus.

1-2 : 실험방법1-2: Experimental Method

도 1에 개략적으로 나타낸 바와 같이, 1차 역삼투 공정을 거친 농축수를 결정화 공정을 수행 후 상등액을 취하여 10, 5 및 0.45 um의 필터(Memtrex MP, GE)를 순차적으로 이용하여 MF(microfiltration)과정을 거쳤다. MF를 통과한 농축수는 RO 유입조에 수집하여 두고 고압펌프의 토출압으로 압력을 확보하여 일정한 유량을 막모듈로 주입하여 가면서 투과수를 얻었다. As schematically shown in Figure 1, after performing the crystallization process of the concentrated water after the first reverse osmosis process to take a supernatant using a filter (Memtrex MP, GE) of 10, 5 and 0.45 um sequentially using MF (microfiltration) I went through the process. The concentrated water passing through the MF was collected in the RO inflow tank and the pressure was ensured by the discharge pressure of the high pressure pump, and a constant flow rate was injected into the membrane module to obtain permeate.

구체적인 실험조건은 표 2에 나타내었다. Specific experimental conditions are shown in Table 2.

실험조건Experimental conditions 실험 유입수Experimental influent 범위range 온도(℃) Temperature (℃) 1-stage brine1-stage brine 25 25 운전 압력(bar) Operating pressure (bar) 1-stage brine1-stage brine 58 58 pHpH 1-stage brine1-stage brine 9.6  9.6 CO 2 (L/min) CO 2 (L / min) 1-stage brine1-stage brine 9.3  9.3 pH 조절제pH regulator 1-stage brine1-stage brine Ca(OH)2 Ca (OH) 2

상기 결정화(crystallization) 공정에서는 유입수의 온도는 25℃로 고정시키고 CO2의 유입량은 9.3L/min, pH는 1N Ca(OH)2를 사용하여 9.6으로 조정하였다. In the crystallization process, the temperature of the influent was fixed at 25 ° C., the CO 2 inflow was 9.3 L / min, and the pH was adjusted to 9.6 using 1N Ca (OH) 2 .

실험장치 운전 중 MF를 통과하는 유량은 9.5 L/min, SWRO 막을 통과하는 유량은 9.5 L/min, SWRO 운전압력은 58 bar로 고정시키고 실험을 실시하였다.The experiment was conducted with the flow rate through the MF at 9.5 L / min, the flow rate through the SWRO membrane at 9.5 L / min, and the SWRO operating pressure at 58 bar.

시료에 함유되어 있는 이온들의 분석은 각 단계별로 시료를 취수하여 ICP(ICPE-9000, SHIMADZU)를 이용하여 수행하였다.
Analysis of the ions contained in the sample was performed by using the ICP (ICPE-9000, SHIMADZU) by taking the sample in each step.

1-3 : 실험결과1-3: Experimental Results

표 3은 pH 조절에 의한 결정화 공정을 수행하기 이전 농축수(brine (1)) 및 투과수(permeate (1))의 성상을 나타낸 것이고, 표 4는 pH 조절에 의한 결정화 공정을 수행한 후의 농축수(brine (2)) 및 투과수(permeate (2))의 성상을 나타낸다. Table 3 by pH control The properties of brine (1) and permeate (1) before the crystallization process is shown. Table 4 shows the brine (2) after the crystallization process by pH adjustment. And the property of permeate (2).

표 5는 회수율을 나타내며, 회수율을 구하는 식은 다음과 같다. Table 5 shows the recovery rate, and the formula for obtaining the recovery rate is as follows.

회수율 = (permeate(2) flow / brine(1) flow) x 100Recovery = (permeate (2) flow / brine (1) flow) x 100

표 6은 결정화 공정을 적용한 다단 SWRO system의 양이온 제거율을 나타낸다. Table 6 shows the cation removal rate of the multi-stage SWRO system to which the crystallization process is applied.

(mg/L)(mg / L) B+ B + Ca2+ Ca 2+ K+ K + Mg2+ Mg 2+ Na+ Na + feedfeed 4.574.57 402402 684684 11301130 97109710 brine (1)brine (1) 6.586.58 784784 12561256 28542854 1985019850 permeate (1)permeate (1) 1.641.64 1.721.72 9.989.98 3.653.65 　273273

(mg/L)(mg / L) B+ B + Ca2+ Ca 2+ K+ K + Mg2+ Mg 2+ Na+ Na + 결정화 후 상등액 Supernatant after crystallization 2.582.58 764764 596596 13101310 79407940 MF 후After MF 2.472.47 761761 687687 12801280 76007600 brine (2)brine (2) 2.862.86 900900 734734 15301530 2110021100 permeate (2)permeate (2) 0.480.48 2.252.25 22.822.8 3.243.24 524　524

결정화 공정을 도입한 SWRO 공정SWRO Process with Crystallization Process 전통적인 SWRO 공정Traditional SWRO Process RO 막 유입량 (L)RO membrane inflow (L) 8080 8080 permeate (2) 유량 (L)permeate (2) flow rate (L) 1515 44 회수율 (%)Recovery rate (%) 18.7518.75 55

제거율Removal rate B+ B + Ca2+ Ca 2+ K+ K + Mg2+ Mg 2+ Na+ Na + 결정화 후 상등액Supernatant after crystallization 60.79 60.79 2.55 2.55 52.55 52.55 54.10 54.10 60.00 60.00 permeate (2)permeate (2) 92.71 92.71 99.71 99.71 98.18 98.18 99.89 99.89 97.36 97.36

상기 표 6에 나타난 바와 같이, 본원발명의 후단 역삼투 공정 이전에 결정화 공정을 채택한 경우, 투과수의 보론은 높은 효율로 제거되었다. As shown in Table 6 above, when the crystallization process was adopted before the reverse reverse osmosis process of the present invention, the boron of the permeate was removed with high efficiency.

구체적으로, 보론 농도가 4.57mg/L인 해수 원수에 1단 SWRO 공정을 거치면서 1단 농축수(brine (1))의 보론 농도는 6.58mg/L로 증가하였다. 보론의 농도가 농축된 1단 농축수에 본 발명과 같이 결정화 공정을 도입한 2단 SWRO 공정을 수행한 결과, 생산되는 담수(permeate (2))의 보론 농도는 0.48mg/L로 92.71%의 제거율을 나타내었다. 이는 한국뿐만 아니라 WHO 수질 기준을 만족하는 것이다.Specifically, the boron concentration of brine (1) was increased to 6.58 mg / L as the boron concentration was 4.57 mg / L. As a result of performing a two-stage SWRO process in which the crystallization process was introduced in the first stage concentrated water having a concentration of boron, the boron concentration of the produced fresh water (permeate (2)) was 0.48 mg / L, which was 92.71%. The removal rate is shown. This satisfies WHO water quality standards as well as Korea.

그리고 Ca2 +, K+, Mg2 +, Na+ 등 다른 양이온의 경우도 97.36% ∼ 99.89%의 제거율을 나타내었다.And Ca 2 +, K +, Mg 2 +, Na + , etc. In the case of other cations is shown the removal rate of 97.36% ~ 99.89%.

또한, 표 5에 나타난 바와 같이, 본원발명은 회수율의 측면에서도 높은 효과를 나타내었다. 즉, 전통적인 SWRO 공정에서는 5%의 회수율을 보이지만 결정화 공정을 도입한 본원발명의 2단 SWRO 공정의 회수율은 18.75% 즉, 약 4배에 가까운 높은 회수율을 나타냄을 확인할 수 있다. In addition, as shown in Table 5, the present invention showed a high effect in terms of recovery. That is, although the recovery rate of 5% in the conventional SWRO process, the recovery rate of the two-stage SWRO process according to the present invention incorporating the crystallization process is 18.75%, that is, it can be seen that the high recovery rate is nearly four times.

Claims (7)

i) 해수에 전단 역삼투막을 이용하여 역삼투 공정을 수행하는 단계;
ii) 단계 i)에서 역삼투막을 통과하지 않은 농축수의 pH를 조절하여 전결정 공정 및 여과공정을 수행하는 단계;
iii) 단계 ii)의 여과수에 후단 역삼투막을 이용하여 역삼투 공정을 수행하는 단계; 및
상기 i) 내지 iii) 후에 전단 역삼투막을 통과한 투과수와 후단 역삼투막을 통과한 투과수를 합하는 단계;
를 포함하고, 상기 전결정 (pre-crystallization) 공정은 CO2를 나노버블링 장치로 공급하면서 수행하는 것을 특징으로 하는 해수 내 보론의 제거방법.
i) performing a reverse osmosis process using a shear reverse osmosis membrane in seawater;
ii) adjusting the pH of the concentrated water that has not passed through the reverse osmosis membrane in step i) to perform a precrystallization process and a filtration process;
iii) performing a reverse osmosis process using a reverse reverse osmosis membrane in the filtered water of step ii); And
Combining i) through iii) the permeate that has passed through the reverse reverse osmosis membrane and the permeate that has passed through the reverse reverse osmosis membrane;
And the pre-crystallization process is performed while supplying CO 2 to a nanobubbling device.
제1항에 있어서, 상기 전결정 (pre-crystallization) 공정은 농축수의 pH를 9.0 ~ 10.5 영역으로 조절함으로써 수행되는, 해수 내 보론의 제거방법.
The method of claim 1, wherein the pre-crystallization process is performed by adjusting the pH of the concentrated water to a range of 9.0 to 10.5.
제1항에 있어서, 상기 pH 조절은 Ca(OH)2, NaOH 또는 KOH의 첨가에 의해 수행되는, 해수 내 보론의 제거방법.
The method of claim 1, wherein the pH control is performed by the addition of Ca (OH) 2 , NaOH or KOH.
제1항에 있어서, 상기 pH 조절은 Ca(OH)2 첨가에 의해 9.6으로 조절되는 것을 특징으로 하는, 해수 내 보론의 제거방법.
The method of claim 1, wherein the pH control is adjusted to 9.6 by adding Ca (OH) 2 , method of removing boron in sea water.
삭제delete 제1항에 있어서, 상기 여과는 0.1 내지 100 um의 필터를 이용하여 수행되는 것을 특징으로 하는, 해수 내 보론의 제거방법.
The method of claim 1, wherein the filtration is performed using a filter of 0.1 to 100 um.
삭제delete
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WO2018236184A2 (en) 2017-06-23 2018-12-27 씨제이제일제당(주) Method for producing d-psicose from d-psicose borate complex using chromatography and composition containing d-psicose
US11028420B2 (en) 2017-06-23 2021-06-08 Cj Cheiljedang Corporation Method for producing D-psicose from D-psicose borate complex using chromatography and composition containing D-psicose
CN116177557A (en) * 2023-01-13 2023-05-30 格尔木藏格锂业有限公司 Method for preparing borax from wastewater containing boron discharged from electrodialysis process section

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