Various methods for suppressing the membrane fouling have been investigated over the last two decades. For instance, micropatternings including lines, pillars or pyramids on the porous membrane surface as a passive strategy and coating nanoparticles including TiO2, silver and chitosan on the membrane as an active strategy have been verified useful in improving fouling resistance. Here we successfully fabricated biomimeticpatterned ultrafiltration membranes with high pattern fidelity to enhance the fouling resistance. Also, we investigated the synergistic effect of biomimetic patterns and nanoparticles on fouling resistance of our UF membranes. The excellent long-term performance of our nanoparticles containing patterned biomimetic UF membranes in membrane bioreactor further demonstrated its feasibility for ultrafiltration applications.

분리막에 관한 최신의 연구에서는 다양한 분야의 기술을 분리막 분야에 차용하여, 분리막의 성능을 증진시키고 있다. 특히 나노기술과 분리막 제조 기술의 융합연구는 최신 분리막 연구 분야의 하나로 주목받고 있으며, 다양한 나노-하이브리드 분리막이 연구되고 있다. 본 연구에서는 1) 패터닝 기술을 도입한 패턴 분리막의 제조 - 나노 기술의 하나인 패터닝 기술을 분리막 제조 공정에 융합하여, 표면이 패턴화된 분리막을 제조하고 그 성능을 평가하였다. 2) MIL-100(Fe)/CS 등의 나노 입자를 포함하는 분리막의 제조 - 특별한 목적을 가지고 있는 나노입자(MIL-100(Fe)/CS의 경우 항균성 및 친수성)를 분리막 제조에 적용하여 분리막의 막오염 저감 효과를 증진한 분리막을 제조하였다. 에 대한 연구 결과를 발표하고자 한다.

폴리아마이드 역삼투 분리막은 우수한 분리성능(염제거율, 수투과도)으로 인해, 해수담수화 공정의 핵심소재로 널리 사용되어오고 있다. 하지만, 해수내 존재하는 오염원에 의해 막표면이 오염(파울링)되어 성능이 저하되는 문제점을 가지고 있어, 분리막의 내오염성을 향상시키기 위한 많은 연구가 이루어져 왔다. 기존 연구는 주로 분리막 표면을 화학적으로 개질하는 방식에 의존하였으나, 장기간 내오염성이 유지되지 못하는 단점을 가지고 있다. 최근 분리막의 표면구조를 제어하여 내오염 특성을 부여하려는 연구가 시도되어 왔다. 본 연구에서는 새로운 분리막 표면구조 제어기술을 활용하여, 내오염특성이 우수한 생체의 표면구조를 모사한 역삼투 분리막을 제조하고, 우수한 내오염성을 구현하였다.

Membrane bioreactor (MBR) and reverse osmosis (RO) process have attracted much attention in the field of wastewater treatment and desalination, respectively. However, MBR has membrane fouling which is the major obstacle in maximizing their efficiency. Also, for the RO process, low energy efficiency still remains unanswered in RO process. In this study, it is demonstrated that the application of graphene oxide (GO) to membrane fabrication can be a novel strategy to overcome the residual problems. In detail, GO was applied to fabrication of polysulfone ultrafiltration membrane for improving anti-biofouling capability of membrane. Furthermore, addition of GO enhanced mechanical strength of highly porous support layer, which enabled the thin-film composite RO membrane to have 1.6 to 4 times higher water flux compared to other RO membranes.

수처리 분야에서 분리막은 MBR(membranebioreactor), RO(reverse osmosis), NF (nanofiltration) 등의 공정에서 활발히 사용되고 있다. 그러나 분리막을 이용한 공정에서 가장 큰 문제점 중에 하나인 막오염 현상은 여전히 풀어야 할 문제로 남아있다. 본 연구에서는 막오염 현상을 완화시키기 위해 분리막의 표면에 다양한 모양의 패턴을 도입하였다. 이후 제조한 패턴형 분리막을 이용하여 교차형흐름 반응조에서 미생물의 부착 정도를 평가 해본 결과 패턴형 분리막에서 확연한 막오염 저감 효과를 확인하였다. 또한 패턴형 분리막에서의 막오염 저감메커니즘을 CFD를 이용해 해석해보았다.

The simultaneous determination of residual pesticides was developed using a gas chromatography. In this study, a simple and reliable methodology was improved to detect 175 kinds of residual pesticides by a liquid-liquid extraction procedure, followed by chromatographic analysis by gas chromatography. The 175 kinds of residual pesticides was classified into 4 groups according to the chemical structure, column type, resolution and sensitivity. The soybean sample selected for recovery experiment was not detected any pesticides. The recovery rates were ranged from 70.6% to 119.7% in most pesticides. The relative standard deviation (RSD 0.3~5.6%) was lower than 5.6% in all cases. The limits of detection (LOD) was lower than the maximum residue levels established by Korean legislations. The method has been successfully applied to the analysis of approximately 130 real samples.

We were carried out to monitor pesticide residues in herbal medicine. In Korea Pharmacy, these are no critics for pesticides except 5 kinds of organic chlorines (BHC, DDT, Aldrin, Endrin, Dieldrin) and heavy metals. We analysed 53 kinds of pesticides consisted of 14 kinds of organochlorines, 20 kinds of organophosphoruses, and 19 kinds of pesticides estimated endocrine disruptor on 373 samples consisted with 30kinds of herbal medicine. In this study, Domestic, Chinese and Japanese herbal medicines were tested with GC/ECD, GC/NPD and then confirmed with GC/MSD. Recoveries were 75～110% in ECD detector and 76～97% in NPD detector. Detection limits were 0.004～0.064ppm in ECD detector and 0.006～0.094ppm in NPD detector. Organochlorines and others were not detected in samples.

The simultaneous analysis of multi-residual pesticides was developed using a gas chromatography (GC) method. In this study, a simple and reliable methodology was improved to detect 154 kinds of pesticides in ginseng extract sample by using a liquid-liquid extraction procedure, open column chromagraphy and chromatographic analysis by GC electron capture detector (ECD) and GC nitrogen-phosphorus detector (NPD). The 154 kinds of pesticides were classified in 4 groups according to the chemical structure. The extraction of pesticides was experimented with 70% acetone and dichloromethane/petroleum ether in order, and cleaned up via open column chromatography (3×30㎝) packed with florisil (30g, 130℃, 12hrs). The final extract was concentrated in a rotator evaporator at 40℃ until dryness. Then the residue was redissolved to 2㎖ with acetone, and analyzed by GC-ECD and GC-NPD. The applied concentration of pesticides was over 1~10㎍/㎖. The recovery tests were ranged from 70.7% to 115.2% with standard deviations between 0.3 and 5.7% of the standard spiked to the ginseng extract sample (Group Ⅰ~Ⅳ). The limit of detection (LOD) ranged from 0.001 to 0.099㎍/㎖ (Group Ⅰ~Ⅳ). The 9 kinds of pesticides were not detected. The developed method was applied satisfactory to the determination of the 154 kinds of pesticides in the ginseng extract with good reproducibility and accuracy.