• Korean Membrane Journal
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• 제5권1호
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• pp.31-35
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• 2003

The permeation characteristics of the wastewater containing Si fine particles were examined by ultrafiltration using the polyolefin tubular membrane module. Flux with time was due to the growth of Si cake deposited on the membrane surface and the pore plugging by fine particles. The rate of flux decline in the initial stage increased with the trans-membrane pressure. The pore blocking resistance was the dominant resistance at the initial period of filtration and the cake resistance began to dominate with the initial pore blocking resistance. The larger pores compared with the fine particles, the more the membrane pores could be blocked by the fine particles. Before and after treatment, the distribution of particle size was shifted toward to the left. Then, the average size of fine particles in the permeate was 20 nm.

• Membrane and Water Treatment
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• 제3권1호
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• pp.51-62
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• 2012

The permeate flux declination along an ultrafilter membrane is due mainly to the concentration-polarization resistance increment and the decline in transmembrane pressure. It was found in previous works that the concentration polarization resistance could be reduced in a ring-rod tubular membrane ultrafilter using the turbulent behavior. In the present study, the performance was further improved by properly and gradually decreasing the baffled-ring distance along the cross-flow channel coupled with properly adjusting the number of baffled rings. This theoretical analysis is based on the mass and momentum balances as well as the application of the resistance-in-series model. The correlation predictions are confirmed with the experimental results for dextran T500 aqueous solution ultrafiltration.

• 한국물환경학회지
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• 제22권1호
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• pp.17-22
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• 2006

This study is about backwash condition and membrane fouling at continuous coagulation/ultrafiltration process in water treatment. The capacity of pilot plant was $0.06m^3/d$. The result of the test, Backwash cycle time and duration time had a significant effect on the efficiency of system and backwash. Backwash duration time was determined to be fixed in 30 seconds for the system with more than 95% recovery rate, It needed 30 minute backwash frequency. During the continuous operation, membrane fouling was analyzed by determining the filtration resistance ($R_i$) and cake layer resistance ($R_c$). At the initial stage, filtration resistance highly influenced the fouling behavior. But after 1.5 hours, cake layer resistance became more important than filtration resistant.

• 한국막학회:학술대회논문집
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• 한국막학회 1991년도 추계 총회 및 학술발표회
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• pp.9-16
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• 1991

The current status of reverse osmosis and ultrafiltration membranes are reviewed with the view for the future. In the case of reverse osmosis (RO) membranes, as examples, new crosslinked aromatic polyamide membranes exhibited the superior separation performance with the sufficient water permeability, the high tolerance for oxidizing agents and chemicals. Ultrafiltration (UF) membrane based on poly(phenylene sulfide sulfone) (PPSS) also exibited the superior separation performance with the high solvent, heat and fouling resistance.

• 멤브레인
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• 제19권2호
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• pp.104-112
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• 2009

본 연구에서는 용매로 N-methyl-2-pyrrollidone을 사용하여, 상전환 방법으로 carboxylic acid를 함유한 음이온성 한외여과막을 제조하였다. 첨가제, 제막조건 및 운전조건에 따른 투과 특성을 알아보았다. Bovin serum albumin (BSA) 수용액의 pH에 따른 상대투과유속을 측정하여 fouling형성에 따른 투과 특성의 변화를 살펴보았다. 투과 특성은 막 제조환경과 투과 공정에 영향을 받았다. 이온교환용량과 측정 온도가 증가할수록, 그리고 BSA의 등전점으로부터 수용액의 pH값이 멀어질수록 상대투과유속이 증가하였다.

• Membrane and Water Treatment
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• 제2권2호
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• pp.91-103
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• 2011

The flux behavior in the separation of equimolar bovine serum albumin (BSA) and bovine hemoglobin (HB) in aqueous solutions by cross-flow ultrafiltration (UF) was investigated, in which polyacylonitrile membrane with a molecular weight cut-off (MWCO) of 100 kDa was used. BSA and HB have comparable molar mass (67,000 vs. 68,000) but different isoelectric points (4.7 vs. 7.1). The effects of process variables including solution pH (6.5, 7.1, and 7.5), total protein concentration (1.48 and 7.40 ${\mu}M$), transmembrane pressure (69, 207, and 345 kPa), and solution ionic strength (with or without 0.01 M NaCl) on the separation were examined. It was shown that the ionic strength had a negligible effect on separation performance under the conditions studied. Although BSA and HB are not rigid bodies, the flux decline in the present cross-flow UF did not result from the mechanism of cake filtration with compression. In this regard, the specific cake resistance when pseudo steady-state was reached was evaluated and discussed.

• Korean Membrane Journal
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• 제3권1호
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• pp.17-23
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• 2001

Polyethersulfone (PES) and cellulose acetate (CA) ultrafiltration (UF) membranes having different molecular weight cut-off values were prepared by immersion precipitation method by changing the compositions of easting solution. Egg white solution was concentrated to volume concentration ratio 4 in tubular UF with membranes made of moderately hydrophobic PES and hydrophilic CA. The process Parameters such as pressure and fluid velocity were controlled in order to apply successfully for egg white solution and to investigate the pressure dependency. The resistance values were measured to investigate the fouling and concentration polarization effect on membrane performance. During concen- tration of egg white solution by UF, the fouling layer appeared to contribute little resistance to flux compared to that of polarized layer.

• 한국식품저장유통학회지
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• 제6권4호
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• pp.424-428
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• 1999

복숭아 착즙액을 분획분자량 30,000인 hollow fiber를 사용하여 공정압력 1.0, 1.5, 2.0 bar, 공정온도 20, 35, 5$0^{\circ}C$에서 투과 플럭스와 총저항을 측정하고 막을 통과한 투과액의 성분분석을 행하였다. 공정압력에 따른 복숭아주스의 투과 플럭스는 압력이 증가함에 따라 투과 플럭스가 거의 직선적으로 증가하는 경향이었으며 공정온도 변화에 따른 투과 플럭스의 변화는 온도가 상승할수록 주스의 점도 감소와 확산계수의 증가로 투과 플럭스는 증가하는 경향이었다. 막을 통과한 투과액의 청징 정도를 검토한 결과 청징 전 후의 당도, 산도는 비슷한 수준이었고 탁도는 월등히 개선되었다. 공정시간에 따른 투과 플럭스의 변화는 청징 초기에는 투과 플럭스가 급격히 감소하다 일정시간이 흐른 후 더 이상 회복되지 않음을 알 수 있었는데 이는 시간이 경과되면서 막오염이 진행되어 저항값이 증가하기 때문으로 사료되었다. 또한 공정압력과 온도가 높을수록 투과 플럭스는 많아지게 되지만 막표면의 겔층이 압축되고 막의 압밀화 현상이 일어나기 때문에 총저항, 겔층 저항값이 높게 나타남을 알 수 있었다.

• Membrane and Water Treatment
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• 제8권2호
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• pp.185-199
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• 2017

Low-pressure membrane filtration is increasingly used for tertiary treatment of wastewater effluent organic matter (EfOM), mainly comprising organic base/neutral compounds. In-line coagulation with underdosing, charge neutralization, and sweep floc conditions prior to ultrafiltration (UF) was studied to determine removals of the EfOM components and consequent reduction of fouling using polyethersulfone membranes. Coagulation and UF substantially reduced fouling for all coagulation conditions while removing from 7 to 38% of EfOM organic acids. From 7 to 16% of EfOM organic base/neutrals were removed at neutral pH but there was no significant removal for slightly acid coagulation conditions even though fouling was substantially reduced. Sweep floc produced the lowest resistance to filtration but may be inappropriate for in-line use due to the large added volume of solids. Charge-neutralization resulted in poor recovery of the initial flux with hydraulic cleaning. Under-dosing paralleled sweep floc in reducing hydraulic resistance to filtration (for sub-critical flux) and the initial flux was also easily recovered with hydraulic cleaning. Hydrophobic and hydrophilic base/neutrals were identified on the fouled membranes but as previously reported the extent of fouling was not correlated with accumulation of organic base/neutrals.

• Membrane and Water Treatment
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• 제7권5호
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• pp.433-449
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• 2016

The successful application of cleaning protocols is vital for optimized filtration processes. A series of experiments with an ultrafiltration ceramic tubular membrane were carried out for the foulants dextran and carboxymethyl cellulose. Firstly, the impact on fouling of concentration changes was investigated with the increase in resistance being used as the key parameter. In the second phase, removal of reversible fouling was also investigated by employing intermittent rinsing consisting of a cold water rinse followed by a hot one. A comparative analysis for both foulants is reported. Across a range of concentrations and for both foulants, the reduction in resistance due to rinsing was found to depend upon concentration (C); it changed as $C^n$ where n was found to be 0.3. A plausible semi-theoretical explanation is given. Thirdly, for both foulants, the application of a combination of strong alkaline solutions with oxidizing agent (mainly sodium hypochlorite) followed by acid was found to be appropriate for cleaning of the ceramic membrane. The effect of increased temperature for cleaning agents followed by a warm water rinse contributed positively to the cleaning capability.