• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.7
• /
• pp.492-497
• /
• 2014

This study investigated removal characteristics of organic matters in pretreatment and reverse osmosis (RO) membrane processes for seawater desalination. Also, the influence of the changes in characteristics of organic matters on the membrane fouling was assessed. The pretreatment processes included dual media filtration (DMF), pressurized membrane filtration (MF), and submerged membrane filtration (SMF). Turbidity, UV absorption at 254 nm, dissolved organic carbon, size exclusion chromatography (SEC), fluorescence excitation emission matrix (FEEM), and transparent exopolymer particles (TEP) in raw and processed waters were analyzed. Ions and minerals were not removed by any pretreatment process tested, but were removed over 99% through the RO membrane process. Hydrophobic organics, which can play major role in organic membrane fouling, were relatively readily removed compared with hydrophilic ones. Membrane based pretreatment such as MF and SMF exhibited better removals of organics than conventional DMF. As the levels of organics in pretreated water decreased, the silt density index (SDI) decreased. MF treated water exhibited the lowest SDI value; this is possibly due to the lowest TEP ($0.1-0.4{\mu}m$) concentrations.

• Applied Chemistry for Engineering
• /
• v.33 no.6
• /
• pp.551-556
• /
• 2022

The desalinated water obtained by the water treatment process based on the membrane is attracting a lot of attention as a promising technology that can solve the global water shortage problem. Reverse osmosis membrane-based desalination, one of the most widely used desalination processes, is a technology that desalinates abundant seawater on Earth, thus having great potential in the desalination industry. To improve the performance of the desalination process, it is necessary to understand the reverse osmosis mechanism of the membrane at the atomic/molecular level. In this review, we introduce molecular simulation, which plays an important role in material research today, and the roles of computational simulation at the atomic/molecular level in the development of reverse osmosis membranes.

• Membrane Journal
• /
• v.3 no.2
• /
• pp.51-59
• /
• 1993

해수는 약 3.5%의 여러가지 염류가 용해되어 있는 수용액으로 이러한 용존염류를 제거하여 담수를 얻는 방법으로는 증발법, 냉동법 등과 같이 물의 상변화를 이용하는 방법과 역삼투압법, 전기투석법과 같이 분리막을 이용하여 압력차, 전위차로 분리하는 방법이 실용화되어 있다. 이중에서 역삼투압법은 상변화가 필요없기 때문에 소요에너지가 적고 장치가 Compact하여 설치비 및 설치부지가 적게 든다는 이점을 가지고 있으며, 특히 최근에는 우수한 분리막의 개발 및 공정기술의 향상으로 다른 공정들에 비해 경쟁력을 갖게 되었다.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1993.06a
• /
• pp.57-81
• /
• 1993

해수는 약 3.5%의 여러가지 염류가 용해되어 있는 수용액으로 이로한 용존염류를 제거하여 담수를 얻는 방법으로는 증발법, 냉동법 등과 같이 물의 상변화를 이용하는 방법과 역삼투압법, 전기투석법과 같이 분리막을 이용하여 압력차, 전위차로 분리하는 방법이 실용화 되어 있다. 이 중에서 역삼투압법은 상변화가 필요없기 때문에 소요에너지가 적고 장치가 COMPACT하여 설치비 및 설치부지가 적게 든다는 이점을 가지고 있으며, 특히 최근에는 우수한 분리막의 개발 및 공정 기술의 향상으로 다른 공정들에 비해 경쟁력을 갖게 되었다.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.4
• /
• pp.251-257
• /
• 2014

This research is focused on coagulation and sand filtration process as a pretreatment of RO seawater desalination. RO systems require sufficient and reliable pretreatment process to produce superior quality of RO feedwater that can mitigate RO membrane fouling. This experiment was conducted to investigate the effectiveness of coagulation and filtration process under various experimental conditions including different coagulant dose, flocculation mixing intensity and time, turbidity, and filtration rate. The experimental results showed that the optimum pretreatment conditions resulting in lower SDI value suitable for RO feedwater were coagulation pH 6.5, raw water turbidity greater than 4 NTU, and media bed depth greater than 550 mm. However, flocculation mixing intensity, coagulant dose, and filtration rate relatively affected little on the filtration efficiency.

• Applied Chemistry for Engineering
• /
• v.34 no.4
• /
• pp.331-346
• /
• 2023

Recently, green processes that can be directly used in an energy-efficient and electrified society to achieve carbon neutrality are attracting attention. Existing heat and pressure-based desalination technologies that consume tremendous amounts of energy are no exception, and the growth of next-generation electrochemical-based desalination technologies is remarkable. One of the most representative electrochemical desalination technologies is electrochemical ion separation (EIONS) technology, which includes capacitive desalination (CDI) and battery desalination (BD) technology. In the research field of EIONS, various system applications have been developed to improve system performance, such as capacity and cyclability. However, it is very difficult to understand the meaning and novelty of these applications immediately because there are only a few papers that summarize the research background for domestic readers. Therefore, in this review paper, we aim to describe the technological advances and individual characteristics of each system in clear and specific detail about the latest EIONS research. The driving principle, research background, and strengths and weaknesses of each EIONS system are explained in order. In addition, this paper concluded by suggesting the future development and research direction of EIONS. Researchers who are just beginning out in EIONS research can also benefit from this study because it will help them understand the research trend.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.6
• /
• pp.811-823
• /
• 2009

Seawater desalination process using a reverse osmosis (RO) membrane has been considered as one of the most promising technologies in solving the water scarcity problems in many arid regions around the world. To protect RO membrane in the process, a thorough understanding of the pretreatment process is particularly needed. Seawater organic matters (SWOMs) may form a gel layer on the membrane surface, which will increase a concentration polarization. As the SWOMs can be utilized as a substrate, membrane biofouling will be progressed on the RO membrane surface, resulting in the flux decline and increase of trans-membrane pressure drop and salt passage. In the middle of disinfection, an optimal chlorine dosage and neutralizer (sodium bisulfite, SBS) should be practiced to prevent oxidizing the surface of RO membranes. Additional fundamental research including novel non-susceptible biofouling membranes would be necessary to provide a guide line for the proper pretreatment process.

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.2
• /
• pp.171-176
• /
• 2011

Organic matters that comprise a tiny part of seawater generally occur over 50% of membrane fouling in Reverse Osmosis Process. This study evaluates Foundation efficiency of reverse osmosis membranes under brackish and seawater conditions and resistance of organic fouling. Moreover, analyzing the membrane surface through roughness, contact angle and zeta potential results in roughness and contact angle are proportional to flux decline rate (FDR), yet FDR has high value when zeta potential is low level. Furthermore, with various membrane fouling of different raw water conditions, the flux tends to improve when pH value is high and raw water which is complex with organic and cation pollutes membrane faster than organic separated raw water condition.

• Membrane Journal
• /
• v.32 no.4
• /
• pp.209-217
• /
• 2022

Ion exchange membrane (IEM) is an important class of membrane applied in batteries, fuel cells, chloride-alkali processes, etc to separate various mono and multivalent ions. The membrane process is based on the electrically driven force, green separation method, which is an emerging area in desalination of seawater and water treatment. Electrodialysis (ED) is a technique in which cations and anions move selectively along the IEM. Anion exchange membrane (AEM) is one of the important components of the ED process which is critical to enhancing the process efficiency. The introduction of cross-linking in the IEM improves the ion-selective separation performance due to the reduction of free volume. During the desalination of seawater by reverse osmosis (RO) process, there is a lot of dissolved salt present in the concentrate of RO. So, the ED process consisting of a monovalent cation-selective membrane reduces fouling and improves membrane flux. This review is divided into three sections such as electrodialysis (ED), anion exchange membrane (AEM), and cation exchange membrane (CEM).

• Clean Technology
• /
• v.20 no.1
• /
• pp.13-21
• /
• 2014

Because of the water scarcity caused by the increase of salinity in the underground water, seawater desalination stands out as one of the most promising solution. As there are so much energy costs in operating desalination plants, new hybrid process which is more effective should be researched. A geothermal VMD (vacuum membrane distillation) hybrid process is a competitive alternative for seawater desalination. Because geothermal energy has significant characteristics of high capacity factor to operate the power plant at full capacity for 24 hour per day, it can be a priority heat source of VMD superior to any other renewable energies such as solar and wind power. In this study, we design a geothermal VMD hybrid process, analyze it economically and finally compare the result with a case of conventional VMD process. Geothermal VMD hybrid process generates $23,822,409 of NPV (net present value) more than the conventional VMD process in case of 5% discount rate. The break-even point between these processes is 5.36 year. Sensitivity analysis indicates that steam cost is the most decisive influence variable to the economic outcome.