• Journal of Korean Society of Water and Wastewater
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• v.29 no.2
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• pp.233-241
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• 2015

Polytetrafluoroethylene (PTFE) membrane has high resistance to chlorine, which is a great advantages in chemical cleaning to recover water flux during membrane processes in drinking water systems. A humic kaolin water with approximately 4 mg/L of DOC and 10 NTU of turbidity was prepared as a feed water. Coagulation pretreatment with or without settling was applied. The coagulation with settling showed the greatest water production. The reduced flux was effectively recovered by NaOCl cleaning, i.e., 21% recovery by 50 mg/L of NaOCl cleaning and 49% recovery by 500 mg/L NaOCl cleaning. The images of SEM and AFM analyses were corresponded to the water flux variation. However, when the floc was accumulated on the membrane surfaces, the efficiency of NaOCl cleaning was substantially limited. In addition, dynamic contact angle became greater after cleaning, which indicates changes in characteristics of fouling layer such as surface hydrophobicity. Proper cleaning technologies during enhanced backwash using NaOCl would expand application of PTFE membranes in drinking water systems.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.133-136
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• 1998

0.1 내지 $4 \mum$의 입도분포를 가진 kaolin용액을 dead-end형 여과 장치(Amicon Cell, 8050)를 이용하여 공칭세공이 $0.2 \mum$인 PTFE막으로 농도 및 운전압력에 따른 투과실험을 하였다. Kaolin 용액의 투과유속은 케이크 저항이 지배적이었으며 초기에는 분리막 표면에 케이크가 형성되고 그 후에 분리막 세공의 오염이 발생하는 것으로 관찰되었다.

• Membrane Journal
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• v.9 no.4
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• pp.221-229
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• 1999

The nominal pore size 0.2 ${\mu}m polytetrafluroethylene(PTFE, Satorius Co,) membrane was used for the filtration of 0.1 wt% kaolin, bentonite, yeast, and starch solution, respectively. After filtration, the membrane was cleaned and the pore size was measured by liquid displacement method(LDMl using water/iso-butanol system. The pore size for new PTFE membrane evaluated by LDM was comparable with those of which were measured by mercury porosimetry and scanning electron microscope. The membrane pores were severely fouled, and constricted to below 0.3 ${\mu}m in the cases of bentonite and starch solution which contained smaller particles than pores. However, in the case of kaolin - solution, only some parts of membrane pores above 0.35 ${\mu}m were slightly fouled. Hence, the phenomena of membrane fouling could be identified quantitatively by the evaluation of pore size using LDM.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.04a
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• pp.101-104
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• 1999

PEFE, Asypore, PC, Nylon 등의 정밀여과막에 0.1내지 4$\mu\textrm{m}$의 입자분포를 가진 kaolin 용액을 dead-end 형 여과장치(Amicon Cell, 8050)를 이용하여 투과실험을 하였다. 또한 공칭세공이 0.2$\mu\textrm{m}$ 인 PTFE(Sartorius 사) 막에 kaolin, bentonite, yeast, starch 등 입자의 크기 및 특성이 다른 0.1%의 용액들을 1 bar 의 운전압력과 200rpm의 회전속도로 투과실험을 하였다. 투과 실험한 자료를 근거로 저항모델을 적용하여 분석하였으며 순수 하락도와 액체전이법으로 세공분포를 확인하였다.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.981-987
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• 2011

Biologically treated water contains a large quantity of organic matters and microorganisms which can cause various problems to membrane. The membrane fouling occurred by these reasons is hard to control by single physical cleaning. This study analyzes the efficiency of aeration with chemical backwashing and foulants removal during chemical backwashing. The cleaning efficiency improves when the chemical concentration is high and the contact time of chemical is long. Chemical backwashing with aeration shows exceptional cleaning efficiency which leads the physical cleaning is required during chemical backwashing since it forms flow inside the membrane submerged tank. From the foulants removal analysis, the particles such as turbidity and TOC removal rate increase when the aeration is applied. Dissolved matter of DOC and UV254 removal is dependent on higher chemical concentration. According to FTIR analysis, one of major foulants, the polysaccharide is controlled by the chemical backwashing with aeration condition.

• Membrane Journal
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• v.10 no.4
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• pp.230-233
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• 2000

The aqueous glucose solution was separated by the membrane distillation with hydrophobic pojytetrafluoroethylcnc microfiltration membrane, The nominal pore size of the membrane was 0.2${\mu}m$. As the operating temperature increased from 40$^{\cirt}C$ to 70$^{\cirt}C$, the membrane permeation flux increased from 3.6 LMH to IL2 LlVIH, but the glucose rejection decreased 99% to 65% Also, the permeation nux and rejection decreased 25% and 6%, respectively, as the concentration of glucose solution increased 2 wt% to 4 wt%.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.31-36
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• 2008

This work was performed to evaluate the effect of membrane material and structure on fouling in a submerged membrane bioreactor(MBR). Three types of microfiltration membranes with the same pore size of 0.1 $\mu$m but different materials, polytetrafluoroethylene (PTFE), polycarbonate(PCTE) and polyester(PETE), were used. While PETE membrane exhibited the most rapid flux decline throughout the operation, PCTE and PTFE had a similar tendency with regard to permeability. Difference in permeability between PETE and the other membranes gradually decreased with time, which was probably due to chemical cleaning. The higher TOC rejection of PETE membrane could be attributable to its faster fouling, resulting from a larger amount of foulants to get attached to the membrane in a shorter time. DOC fractionation using a DAX-8 resin showed that the composition of each fraction between the supernatant and permeates did not change significantly with operation time, indicating that membrane hydrophilicity/hydrophobicity was not a dominant factor affecting to MBR fouling in this study. Compared to other membranes, the fouling of PETE membrane was more influenced by pore clogging (irreversible fouling), which would probably contribute to a higher organic rejection of the PETE membrane.