• Membrane and Water Treatment
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• 제6권2호
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• pp.161-172
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• 2015

Forward osmosis (FO) is an emerging membrane technology with potential applications in desalination and wastewater reclamation. The osmotic pressure gradient across the FO membrane is used to generate water flux. In this study, flux performance and foulant deposition on the FO membrane were systematically investigated with a co-current cross-flow membrane system. Sodium alginate (SA), bovine serum albumin (BSA) and tannic acid (TA) were used as model foulants. Organics adsorbed on the membrane were peeled off via oscillation and characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). When an initial flux of $8.42L/m^2h$ was applied, both flux reduction and foulant deposition were slight for the feed solution containing BSA and TA. In comparison, flux reduction and foulant deposition were much more severe for the feed solution containing SA, as a distinct SA cake-layer was formed on the membrane surface and played a crucial role in membrane fouling. In addition, as the initial SA concentration increased in FS, the thickness of the cake-layer increased remarkably, and the membrane fouling became more severe.

• Membrane and Water Treatment
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• 제5권2호
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• pp.73-86
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• 2014

Membrane fouling is a major challenge limiting the use of membrane applications. In this study high induced shear rates were utilized at the membrane surface in order to reduce the organic and inorganic scaling by using the torsional vibration of flat sheet membranes. The performances of a vibratory shear-enhanced processing (VSEP) system for the ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membrane filtration of industrial dairy wastewater were investigated. The vibration and non-vibration methods were compared with the same membrane and operational parameters during the purification of real dairy industrial process wastewater. In the initial experiments, short-term tests were carried out in which the effects of vibration amplitude, recirculation flow rate and transmembrane pressure were measured and compared. The permeate flux, turbidity, conductivity and chemical oxygen demand (COD) reduction of dairy wastewater were investigated by using UF, NF and RO membranes with vibration and non-vibration methods. In the subsequent experiments, concentration tests were also carried out. Finally, scanning electron microscopy (SEM) revealed that the vibration method gave a better performance, which can be attributed to the higher membrane shear rate, which reduces the concentration of solids at the membrane, and the transmission.

• 한국막학회:학술대회논문집
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• 한국막학회 2005년도 춘계 총회 및 학술발표회
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• pp.29-33
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• 2005

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 춘계 총회 및 학술발표회
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• pp.45-45
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• 1995

Filtration, one of the most important process in the various industrials, is defined as the separation of two or more compounds from a fluid by passing the mixture refers to the separation of solid, immisible particles from liquid or gaseous mixture. Membrane filtration which is a type of filtration extends it's application further to include the separation, concentration, and filtration. The main objective of this investigation is the preparation of organic solvents-resistant polyimide membranes by using phase inversion technique and their application as a UF membrane. Specially, the dope solution was prepared from the newly developed method. The newly developed method is that the dope solution was directly prepared from the polyimide solution which was prepared by the modified one-step polymerization. The effects of the parameters for membrane preparation such as the casting solution composition and the casting conditions were investigated and the performance and chemical stabfiity of membrane are going to be tested.

• 상하수도학회지
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• 제19권3호
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• pp.312-317
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• 2005

The 15 month pilot study was performed to investigate the effect of pretreatment by monochloramine ($NH_2Cl$) on the performance of RO membranes made of cellulose acetate (CA) and polyamide (PA). Both RO membranes experienced severe biological fouling without any pretreatment during the treatment of highly organic surface water in Florida, USA. Feed monochloramination at 5 mg/L significantly minimized productivity loss by effective control of biofouling. The CA membrane did not show any structural damages by monochloramine, while the PA membrane suffered from a gradual loss of membrane integrity by chlorine oxidation, which was characterized as an increase in productivity and a decrease in selectivity. The degradation of PA membrane increased with increasing monochloramine dose.

• 유기물자원화
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• 제29권3호
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• pp.5-16
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• 2021

본 연구에서는 MBR 공정 내 폭기조에서 순산소 용해와 일반 공기 폭기의 효율에 대한 비교·평가를 통해 순산소의 MBR 공정 적용성에 대해 평가 하였다. 순산소 장치에 의한 유기물 및 암모니아 산화 여부에 대해 평가하였으며, 실폐수(음식물류 폐기물의 혐기성소화 유출수) 적용 과포화산소용해 효율 평가를 진행하였다. 순산소용해와 일반공기폭기 방법의 SCOD, 암모니아 제거율과 속도는 비슷하였다. 하지만, 순산소 용해에 의한 미생물 수율이 일반공기폭기법에 의한 미생물 수율보다 약 0.03 g MLSS-produced/g SCOD-removed 낮아 잉여슬러지 처리 비용이 감소될 수 있을 것이라 판단된다. 음식물류 폐기물의 혐기성 소화 유출수의 고농도 유기물 (4,000 mg/L) 및 암모니아 (1,400 mg/L)의 제거율을 순산소용해와 일반공기폭기법을 비교한 결과, 순산소 용해기가 일반공기폭기법에 비해 유기물 제거율이 약 13% 가량 더 높게 평가되었다. 또한, MLSS의 경우 일반공기폭기법이 순산소장치에 비해 0.3배가량 높았다. 이는, 순산소장치의 경우 폭기조 내에 용존산소가 충분히 유지, 공급되기 때문에 슬러지 자산화가 고도로 진행된 결과로 판단되었다. 따라서, 고농도 유기물을 함유한 폐수 처리를 위한 방법으로는 기존에 많이 사용되었던 일반공기폭기법보다 순산소장치를 활용하는 것이 경제적인 면에서 더 유리할 것으로 판단되었다.

• 상하수도학회지
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• 제13권1호
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• pp.61-71
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• 1999

For a high-rate fermentation and recovery of organic acid, we have developed a new organic acid fermentation reactor with membrane filter, which is the most important part in the new advanced wastewater treatment system. The recovered organic acid is to be reused as an organic carbon source at denitrification process. Some experiments were conducted to compare the performance of acid fermentation at different SRTs, such as 5, 10, and 20 days. The total organic acid concentration produced during the runs was in the range of 2,100-2,900 (mgC/L). The conversion efficiency from substrate to organic acid reached to from 43% to 59%. The recovery rate of organic acid from substrate based on TOC was from 26% to 53%. Regardless of operational conditions, it has been able to maintain the membrane flux constantly, in the range of 0.4-0.46 ($m^3/m^2/day$). The transmembrane pressure drop was 0.2-0.3 (kg/cm) for 100 day's operation. The result of simulation is as follows. Organic removal efficiency of the new advanced treatment system is 95%. 73% of Nitrogen is removed. The removal efficiency of Phosphorus is 93%. By coqulation, soluble phosphorus is able to remove from the water treatment lines, which is impossible at conventional activated sludge system. The unit construction cost is 65000 (yen/m3) and it was 1.4 times than that of the standard activated sludge system. The unit operation cast is 7.7 ($yen/m^3/day$) and it was 1.3 times than that of the standard activated sludge system.

• 대한화학회지
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• 제59권5호
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• pp.413-422
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• 2015

연료전지는 수소와 산소를 연료로 하여 전기를 생산해 내는 장치로, 전기분해에 의해 음극에서 생성된 수소이온을 양극으로 전달할 수 있는 전해질을 필요로 한다. 전해질로써 Nafion과 같은 불소계 고체 고분자 막이 개발되어 왔으나, 고온에서의 수소이온 전도도 감소 및 높은 함수율에 따른 안정성 감소 등의 문제로 인해 새로운 연료전지용 고분자 전해질 막의 개발을 필요로 하였다. 본 연구에서는 술폰산기가 밀집된 구조를 갖는 단량체를 이용함으로써 높은 수소이온 전도도를 확보하고 이에 따른 고분자 막의 높은 함수율은 고분자 사슬 내에 나이트릴(CN) 작용기를 친수성 올리고머에 함께 도입함으로써 고분자 사슬간 쌍극자-쌍극자 상호작용을 통해 극복할 수 있도록 하였다. 결과적으로 물리적 가교가 형성된 고분자 막들은 높은 함수율 대비 우수한 치수안정성을 나타내었으며, 모든 조성에서 Nafion-117 고분자막에 비해 낮은 IEC값을 가짐에도 불구하고 보다 높은 전도도를 나타내었다.

• Membrane and Water Treatment
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• 제11권4호
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• pp.257-274
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• 2020

There are many previous review articles are available to summarize either the characterization methods of effluent organic matter (EfOM) or the individual control treatment options. However, there has been no attempt made to compare in parallel the physicochemical treatment options that target the removal of EfOM from biological treatments. This review deals with the recent progress on the characterization of EfOM and the novel technologies developed for EfOM treatment. Based on the publications after 2010, the advantages and the limitations of several popularly used analytical tools are discussed for EfOM characterization, which include UV-visible and fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), size exclusion chromatography (SEC), and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS). It is a recent trend to combine an SEC system with various types of detectors, because it can successfully track the chemical/functional composition of EfOM, which varies across a continuum of different molecular sizes. FT-ICR-MS is the most powerful tool to detect EfOM at molecular levels. However, it is noted that this method has rarely been utilized to understand the changes of EfOM in pre-treatment or post-treatment systems. Although membrane filtration is still the preferred method to treat EfOM before its discharge due to its high separation selectivity, the minimum requirements for additional chemicals, the ease of scaling up, and the continuous operation, recent advances in ion exchange and advanced oxidation processes are greatly noteworthy. Recent progress in the non-membrane technologies, which are based on novel materials, are expected to enhance the removal efficiency of EfOM and even make it feasible to selectively remove undesirable fractions/compounds from bulk EfOM.

• 한국막학회:학술대회논문집
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• 한국막학회 1996년도 춘계 총회 및 학술발표회
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• pp.16-19
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• 1996

Separation with synthetic membrane have become increasingly important processes in many fields. In the most application of membrane process, polymer membrane is used. the main advantage of polymers as a material for membrane preparation is the relative simplicity of this film formation which enables one to obtain rather high permeability rates. However, polymeric membranes have several limitations, such as high temperature instability, swelling and decomposition in organic solvent, et. al.. These limitations can be overcome by inorganic membrane. At the present time, commercially available inorganic membranes have pore diameters ranging 5nm to 50mm, and the predominant flow regime in such membrane is Knudsen diffusion. Since the Knudsen permeability is directly proportional to the molecular velocity, gases can be separated due to their molecular masses. However, this separation mechanism is only of important for light gases such as H2 and He. Other separation mechanisms like surface diffusion, active diffusion can play an important role only with very small pore diameters(2nm) and give rise to large permselectivities. Therefore, preparation of inorganic membrane with nano-sized pore have been attracting more and more attention.