• Proceedings of the Membrane Society of Korea Conference
• /
• 2003.11a
• /
• pp.223-225
• /
• 2003

• Membrane Journal
• /
• v.25 no.4
• /
• pp.332-342
• /
• 2015

In this study, to solve the major problem of reverse osmosis (RO) membrane, surface of reverse osmosis membrane was modified by silane-epoxy multi layer. Octyltrimethoxysilane (OcTES) was polymerized to membrane surface via cross-linking by Sol-gel method. n = 8 alkylgroup of OcTES formed the branch structure by self assembly. And for improve fouling resistance of RO membrane, Ether group of ethylene glycol diglycidyl ether (EGDE) was given to improve hydrophilicity of RO membrane surface by ring-opening. To analyze structure of RO membrane surface with FE-TEM and AFM. Membrane surface of the ridge and valley structure and the bridge structure was confirmed due to the multi-layer surface modification of OcTES and EGDE. And through the increase of the roughness, the branch structure was formed well on membrane surface. Through the XPS analysis was identified chemical structure of membrane surface. And confirmed that the hydrophilic surface modification is given to the surface of the film through a Contact angle analysis. In optimization of EGDE surface modification condition, was suitable 0.5 wt% EGDE concentraion and $70^{\circ}C$ ring-opening temperature. In result of fouling resistance test and MFI is SUL-H10, $PA-OcTES_{1.0}$, $PA-OcTES_{1.0}-EGDE_{0.5}$ 68.7, 60.4, 5.4 ($10E-8hr/mL^2$), multi-layer surface modified membrane improved fouling resistance.

• Environmental Engineering Research
• /
• v.16 no.4
• /
• pp.205-212
• /
• 2011

Reverse osmosis (RO) technology has developed over the past 40 years to control a 44% market share in the world desalting production capacity and an 80% share in the total number of desalination plants installed worldwide. The application of conventional and low-pressure membrane pretreatment processes to seawater RO (SWRO) desalination has undergone accelerated development over the past decade. Reliable pretreatment techniques are required for the successful operation of SWRO processes, since a major issue is membrane fouling associated with particulate matter/colloids, organic/inorganic compounds, and biological growth. While conventional pretreatment processes such as coagulation and granular media filtration have been widely used for SWRO, there has been an increased tendency toward the use of ultrafiltration/microfiltration (UF/MF) instead of conventional treatment techniques. The literature shows that both the conventional and the UF/MF membrane pretreatment processes have different advantages and disadvantages. This review suggests that, depending on the feed water quality conditions, the suitable integration of multiple pretreatment processes may be considered valid since this would utilize the benefits of each separate pretreatment.

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.3
• /
• pp.399-405
• /
• 2011

In a desalination technology using RO membranes, chemical cleaning makes damage for membrane surface and membrane life be shortened. In this research cleaning technology using direct osmosis (DO) was introduced to apply it under the condition of high pH and high concentration of feed. When the high concentration of feed is injected to the concentrate side after release of operating pressure, then backward flow occurred from treated water toward concentrated for osmotic pressure. This flow reduces fouling on the membrane surface. Namely, flux of DO was monitored under pH 3, 5, 10 and 12 conditions at feed concentrations of NaCl 40,000 mg/L, 120,000 mg/L and 160,000 mg/L. As a result, DO flux in pH 12 increased about 21% than pH 3. DO cleaning was performed under the concentrate NaCl 160,000 mg/L of pH 12 during 20 minutes. Three kinds of synthetic feed water were used as concentrates. They consisted of organic, inorganic and seawater; chemicals of SiO2 (200 mg/L), humic acid (50 mg/L) sodium alginate (50 mg/L) and seawater. As a result, fluxes were recovered to 17% in organic fouling, 15% in inorganic fouling and 14% of seawater fouling after cleaning using DO under the condition of concentrate NaCl 160,000 mg/L of pH 12.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1992.04a
• /
• pp.1-4
• /
• 1992

기존의 일반적인 에탄올 제조법으로는 1) ethylene의 가수분해, 2)전분이나 당분의 발효, 3)acetylene으로부터 얻은 acetaldehyde의 환원반응이 있다. 기존의 화석연로에 의존하지 않고 에탄올을 생성하는 방법은 발효에 의한 방법이다. 발효에 의해 생성되는 에탄올의 농도는 batch식 발효에서 13-14%, 고정화 발효방법에서 5-10%정도이다. 이를 고순도의 에탄올로 농축하기 위한 방법으로는 증류법, 투과증발법, 역삼투법등이 있으며 증류를 이용하여 농축하는 경우에는 상당히 큰 열에너지를 필요로 한다.

• 한국방재학회:학술대회논문집
• /
• 2010.02a
• /
• pp.102.1-102.1
• /
• 2010

대체수자원 중 막여과 기술에 대한 관심이 지속적으로 높아지고 있다. 하지만, 이러한 막여과 기술에는 fouling이 발생시 효율저감, flux저감, 소모에너지 증대 등 문제점이 발생한다. 이러한 fouling저감을 위해 막 표면특성분석을 통한 기초연구가 필요하다고 보고 이 연구를 진행하였다. AFM을 이용하여 CML입자와 막의 상호작용을 통해 초기 막오염 경향을 예측할 수 있다.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.2
• /
• pp.155-164
• /
• 2004

Many countries, including Korea, suffer from a shortage of freshwater. With increases in population and the quality of life, along with large-scale expansion in industrial and agricultural activities, more freshwater is needed. Available resources, Including ground water, are limited, and desalination presents the opportunity for a new unlimited source of freshwater from the sea. The objectives of this study were to test membrane performance in seawater desalination and to examine the quality of water produced. bath well and sea water were used as water sources. Typically used membrane for seawater desalination and high rejection seawater desalination membrane are maintained at almost same recovery rate and permeate flux, while the conductivity was lower in the operation of typically used seawater membrane. The treated water quality using two types of membranes is satisfied with the Korea drinking water quality standards.

• Membrane Journal
• /
• v.3 no.1
• /
• pp.35-39
• /
• 1993

Reverse osmosis(RO) and pervaporation(PV) membrane separation proceaes were compared with each other experimentally for the system of water-ethanol mixtures by using nylon 4 blended membranes. The separation effciencies of PV were better than those of RO as expected in previous paper covering the theoretical comparisons of both processes, however tbe permeabilities data showed erraerie results due to the membrane imperfections.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1996.09a
• /
• pp.121-145
• /
• 1996

Due to more stringent regulations in drinking water, membrane separation has been playing an increasingly important role. Seawater desalination by reverse osmosis is a typical example and has been used world-wide. Although the existing technology based on coagulation and media filtration is well established and reliable technology, with the advance of industrial and agricultural activities it is difficult for this technology to remove contaminants such as nitrate and synthetic organic chemicals. To meet the drinking water standards and produce higher quality water, several membrane filtration research programs have been initiated which include Japanese MAC21 and New MAC21 projects. In this paper, potable water application of reverse osmosis (RO) and nanofiltration(NF) and their case histories will be explained in more detail.

• Journal of Korean Society of Water and Wastewater
• /
• v.33 no.6
• /
• pp.413-420
• /
• 2019

Pretreatment system of desalination process using seawater reverse osmosis(SWRO) membrane is the most critical step in order to prevent membrane fouling. One of the methods is coagulation-UF membrane process. Coagulation-UF membrane systems have been shown to be very efficient in removing turbidity and non-soluble and colloidal organics contained in the source water for SWRO pretreatment. Ferric salt coagulants are commonly applied in coagulation-UF process for pretreatment of SWRO process. But aluminum salts have not been applied in coagulation-UF pretreatment of SWRO process due to the SWRO membrane fouling by residual aluminum. This study was carried out to see the effect of residual matal salt on SWRO membrane followed by coagulation-UF pretreatment process. Experimental results showed that increased residual aluminum salts by coagulation-UF pretreatment process by using alum lead to the decreased SWRO membrane salt rejection and flux. As the salt rejection and flux of SWRO membrane decreased, the concentration of silica and residual aluminum decreased. However, when adjusting coagulation pH for coagulation-UF pretreatment process, the residual aluminum salt concentration was decreased and SWRO membrane flux was increased.