• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.264-267
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• 2008

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.82-85
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• 2004

Flux-enhancement mechanism of thin-film-composite (TFC) membranes for the reverse comosis (RO) process was newly explained by positron annihilation lifetime spectroscopy (PALS) that has been found to be applied for detecting molecular vacancies or pores having sizes that are equivalent to salt or hydrate ions in RO membrane.(omitted)

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.17-20
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• 1998

1. 서론 : 계면중합은 제조에 따른 박막의 성능 조절이 가능한 이유로 해서 역삼투용 복합막의 주요 제조 방법으로 제시되어 왔다. 계면중합을 응용하여 제조된 복합막의 성능은 반응 단량체의 종류, 용재의 종류, 단량체의 농도, 반응시간, 열처리 유무 및 온도와 시간 등에 의해 변한다. 한편 위의 변수에 절대적인 영향을 받고 아울러 단량체간의 몰 비가 성립하지 않음으로 해서 최적의 막 성능으로 제시되는 조건을 만족하기 위하여 주로 시행착오에 의한 방법을 동원하여 여러 변수에 다른 제조 막의 성능 고찰을 실시하여 왔다. (생략)

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.170-174
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• 2004

Most of thin film composite reverse osmosis membranes include amide linkages, which are susceptible to chlorine attack resulting in N-chloro derivatives. This study examined a new method based on post-treatment of reverse osmosis membrane with various silane derivatives to improve chlorine resistance. The silane derivatives contain one alkyl group and three alkoxy groups such as trifluoromethyltrimethoxysilane, 3-aminopropylmethoxydiethoxysilane and 3, 3, 3-trifluoropropyltrimethoxysilane. Compared to commercial membranes, silane derivatives coated membranes showed significantly enhanced chlorine durability.

• Membrane and Water Treatment
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• v.8 no.3
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• pp.225-244
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• 2017

A novel thin-film nanocomposite (TFN) reverse osmosis (RO)/non-woven fabric (NWF) membrane was prepared by adding zinc oxide (ZnO) nanospheres ($30{\pm}10nm$) during the interfacial polymerization process of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on self-made polysulfone (PSF) membrane/polyester (PET) non-woven fabric support. The improved performance of TFN RO membrane was verified in terms of water contact angle (WCA), water flux, salt rejection, antifouling properties and chlorine resistance. The results showed that the WCA value of TFN RO surface had a continuous decrease with the increasing of ZnO content in MPD aqueous solution. The water flux of composite TFN RO membranes acquired a remarkable increase with a stable high solute rejection (94.5 %) in $1g{\cdot}L^{-1}$ NaCl aqueous solution under the optimized addition amount of ZnO (1 wt%). The continuous testing of membrane separation performance after the immersion in sodium hypochlorite solution indicated that the introduction of ZnO nanospheres also dramatically enhanced the antifouling properties and the chlorine resistance of composite RO membranes.

• Membrane and Water Treatment
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• v.13 no.3
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• pp.139-145
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• 2022

Development in advanced separation processes leads to the significant advancement in polymeric membrane preparation methodology. Therefore, present research investigated the preparation and characterization of cellulose acetate membrane by phase inversion separation method to determine optimized operating parameters. Prepared CA membrane's performance was been analyzed in terms of % rejection and flux. Investigation was conducted to study effect of different parameters such as polymer concentration, evaporation rate, thickness of film, coagulation bath properties, temperature of polymer solution and of the coagulation bath etc. CA membrane was fabricated by taking polymer concentration 10wt% and 11wt% with zero second evaporation time and varying film thickness over non-woven polyester fabric. Effect of coagulation bath temperature (CBT) and casting solution temperature were also been studied. The experimental results from SEM showed that the surface morphology had been changed with polymer r concentration, coagulation bath and casting solution temperature, etc. Lower polymer concentration leads to lower precipitation time giving porous membrane. The prepared membrane was tested for advanced waste water treatment of relevant effluent stream in pilot plant to study flux and rejection behavior of the membrane.

• Membrane Journal
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• v.30 no.2
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• pp.111-123
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• 2020

Growing industrialization and climate change lead to the huge demand for clean drinking water. Desalination of sea water by membrane separation process is one of the alternative and economically viable methods to fulfil the demand for water. In the membrane separation process, the presence of 2D materials enhances the performance of membrane by facilitating the water permeation, salt rejection, flux rate, and selectivity compared to the traditional reverse osmosis thin-film-composite membranes. In this review, composite membranes with different kinds of 2D materials are discussed on the basis of materials synthesis, characterization and desalination process.

• Proceedings of the Membrane Society of Korea Conference
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• 1991.04a
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• pp.9-9
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• 1991

This paper will begin by describing osmosis and how reverse osmosis works. It will show how osmotic pressure affects reverse osmosis operations. It uill explain salt rejection, membrane flux, and recovery rates and the affect that salt built up has on membrane performance. It wil 1 explain the limitations of RO performance and why pretreatment is important. It will describe the two basic types of membrane, asymmetric and thin-film composite and explain the difference between these types plus compare cellulose acetate types to aromatic polyamide type membranes. It will discuss operating efficiences as it compares to feedwater pressure, concentration, temperature and pH. Finally, it will discuss the differences between tubular, plate and frame, hollow fiber and spiral wound element design. It will be a paper that talks about the basics of RO systems and should give a person who is unfamiliar with RO a basic introduction to this type of separation technology.

• Membrane Journal
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• v.26 no.5
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• pp.391-400
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• 2016

In this work, novel thin film composite (TFC) forward osmosis (FO) membranes are developed via interfacial polymerization on the polysulfone (PS) substrate, using TEOS as the a sol-gel reagent to form hydrophilic interlayer polymer between PS and polyamide (PA). The PS substrate was cast on a very thin polyester nonwoven to reduce membrane resistance. With the incorporation of TEOS (tetraethoxy silane) polymer in the interface between PS and PA, the formed TFC FO membrane exhibits better hydrophilicity and improved water flux, and therefore superior membrane performance. By changing the polymerization sequence of PA interfacial polymerization and TEOS sol-gel condensation, the surface properties and performance of FO membranes are changed significantly. The permeability of FO membranes were estimated using the bench-scale FO test equipment. The distribution of the polysiloxane on composite membrane and morphology are also studied with FE-SEM and EDAX. The PS_PA_TEOS membrane showed highly enhanced water flux (79.2 LMH) but reverse salt flux (RSF) value (7.10 GMH) also increased. However, the flux of PS_TEOS_PA membrane increased moderately (54.1 LMH) without increasing RSF value (1.60 GMH) compare with PS_PA membrane.

• Membrane Journal
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• v.24 no.4
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• pp.317-324
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• 2014

It is very well known that the conventional polyamide (PA) thin film composite (TFC) reverse osmosis (RO) membranes have excellent permselective properties, but their chlorine tolerance is not good enough. In this study, to improve such chlorine tolerance, microporous membranes containing hydrophilic functional groups such as -COOH were used as a support to prepare PA TFC RO membranes, employing the conventional interfacial polymerization method. Meta-phenylene diamine (MPD) and 2,6-diamine toluene (2,6-DAT) were used as diamine monomers and tri-mesoyl chloride (TMC) as an acid monomer. The membranes prepared were characterized using various instrumental analytical methods and permeation test set-up. The flux obtained from the membranes prepared so was more than $1.0m^3/m^2day$ at 800 psi of operating pressure, while the salt rejection was over 99.0%. The chlorine tolerance of them was also found to be better than that of the membrane prepared by using conventional polysulfone support without hydrophilic functional groups.