• 자원리싸이클링
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• 제25권4호
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• pp.3-10
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• 2016

전 세계적으로 해수로부터 자원을 회수하기 위한 연구가 활발히 진행되고 있다. 해수 중 붕소농도는 약 4.5ppm로 낮지만 해수 전체의 용량을 고려하면 용존량이 약 5조 4천억 톤에 이른다. 붕소는 300여종의 산업에 필수적으로 사용되는 자원으로 현재 우리나라는 붕소를 전량 수입하고 있고 연간 700억 원 이상을 붕소수입에 지출하고 있다. 본 글에서는 폐수와 해수로부터 붕소를 제거하거나 회수하는 국내 외 연구동향과 관련기술을 소개하였다. 대부분의 연구는 해수담수화 과정에서 붕소를 제거하는 목적으로 진행되었으며, 붕소의 회수는 주로 폐수나 염수에서 이루어졌다. 용존 붕소를 회수하는 기술은 이온교환법이 대표적이며, 흡착-여과막 공법(Adsorption Membrane Filtration, AMF), 용매추출법 등이 있다.

• 상하수도학회지
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• 제31권6호
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• pp.539-549
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• 2017

In water treatment process using microfiltration membranes, manganese is a substance that causes inorganic membrane fouling. As a result of analysis on the operation data taken from I WTP(Water Treatment Plant), it was confirmed that the increase of TMP was very severe during the period of manganese inflow. The membrane fouling fastened the increase of TMP and shortened the service time of filtration or the cleaning cycle. The TMP of the membrane increased to the maximum of $2.13kgf/cm^2$, but it was recovered to the initial level ($0.17kgf/cm^2$) by the 1st acid cleaning step. It was obvious that the main membrane fouling contaminants are due to inorganic substances. As a result of the analysis on the chemical waste, the concentrations of aluminum(146-164 mg/L) and manganese(110-126 mg/L) were very high. It is considered that aluminum was due to the residual unreacted during coagulation step as a pretreatment process. And manganese is thought to be due to the adsorption on the membrane surface as an adsorbate in feed water component during filtration step. For the efficient maintenance of the membrane filtration facilities, optimization of chemical concentration and CIP conditions is very important when finding the abnormal level of influent including foulants such as manganese.

• 대한화학회지
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• 제16권1호
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• pp.1-5
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• 1972

The adsorption kinetics on a membrane filter have been studied by an introduction of acid or alkali in yttrium-90 solution. The change of the adsorption in the filtration process was determined by the filtrate activities with using a microsyringe filter holder connected with a syringe. The over all reaction rate obeyed a reversible first order reaction, and the rate constants thus obtained, showed the values of $k_1$ = 0.12 $sec^{-1}$ and $k_1'$ = 0.039 $sec^{-1}$. As a result of the present studies, it would be reasonable that the rate determining step of the adsorption reaction was the hydrolysis reaction of the adsorbed yttrium ions.

• 대한환경공학회지
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• 제37권3호
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• pp.152-158
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• 2015

본 연구는 소수성 막 재질에 대한 막오염도를 평가하고자 수동흡착의 개념을 도입하여 정상운전을 위한 막 모듈 이외에 수동흡착 시험용 막 모듈을 설치하여 유출을 시키지 않은 상태에서 막 표면에 부착되는 미생물에 의한 막오염 정도를 분석함으로써 소수성 막오염 잠재성을 평가하고자 하였으며, 이때 운전조건으로 유기물 유입부하를 변화시켜 평가하였다. 이와 더불어 오염된 멤브레인을 세 가지 세정방법(두가지 물리적 세정과 화학적 세정)을 통해 막 세정 전후의 막오염 회복률을 평가하였다. 막오염 평가인자로는 반응조 내 MLSS 농도와 EPS 농도를 조사하였으며, 여과저항 값을 산정하여 막오염 전과 후, 세정 3단계 전과 후를 비교 평가하였다. 실험 결과로서, COD 농도가 750 mg/L인 가장 높은 부하량 조건에서 반응조 내 EPS 농도와 수동흡착 시험용 멤브레인의 여과저항 값이 가장 높게 나타났다. 또한 여과저항 값이 초기 운전 시작 후 차이를 보였지만 60일 이후의 최종 여과저항은 거의 일정하게 나타났는데, 이는 막 표면에 부착된 미생물량이 임계점에 이르러 수동흡착만으로는 더 이상의 막오염은 진행되지 않은 것으로 판단된다. PAds 상태에서 유기물 유입부하에 따른 오염된 막의 세정 전후의 여과저항 측정 결과에서는 3단계 세정 후 평균 회복률이 각각 Run 1이 78%, Run 2가 72%, Run 2가 69%로 유기물 부하가 높을수록 회복률이 떨어지는 것으로 나타났으며, 반면에 물리적 세정에 의한 복원률이 40일 경부터 Run 2와 Run 3의 물리적 세정에 의한 회복률이 낮아지는 것으로 보아 높은 유기물 부하로 인한 막표면의 케이크 형성으로 막오염이 심화된 것으로 판단된다.

• 한국응용과학기술학회지
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• 제25권4호
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• pp.503-510
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• 2008

This research is related to the process of refining the raw material, industrial 2-propanone to the 2-propanone of the electronic grade. With this view, the high purity of 2-propanone was obtained through the complex preprocessing(physical adsorption method), distillation process and membrane-filtration of distillate. Impurities were identified by GC and UV, and then we assayed the water content in 2-propanone passing adsorption step made of activated carbon and Zeolite 4A. Furthermore, the distillation was performed with the packed column distillation apparatus to eliminate impurities such as acetaldehyde. Particulates were removed by reduced-pressure filtration through $0.5{\mu}m$ membrane filter and the number of the particulates was measured by particulate counter to confirm the removal of impure particles.

• Environmental Engineering Research
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• 제21권2호
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• pp.109-120
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• 2016

Conventional treatment techniques cannot meet the stringent modern water quality regulations emanating from the need to provide high quality drinking water. Therefore, a number of studies have suggested low pressure membrane filtration as a worthwhile alternative. However, a major constraint to the extensive use of this technology in low and middle income countries is the high operating and maintenance costs caused by the inherent predisposition to membrane fouling. Notwithstanding, pretreatment of feed water using techniques such as coagulation, adsorption, oxidation and bio-filtration is believed to control fouling. In this review paper, the existing scientific knowledge on membrane fouling and pretreatment techniques for controlling fouling in low pressure membranes is analyzed with the aim of providing new and valuable insights into such techniques, as well as unveiling crucial issues noteworthy for further studies. Among the techniques reviewed, coagulation was observed to be the most cost-effective and will remain the most dominant in the coming years. Although oxidants and magnetic ion exchange resins can also control fouling, the propensity of oxidants to form health treating precursors and the high economic implications of magnetic ion exchange resins will hinder their adoption in developing countries.

• Membrane and Water Treatment
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• 제9권6호
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• pp.473-480
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• 2018

The effect of three iron-based adsorbents pre-depositing on ultrafiltration membrane for humic acid (HA) removal and membrane fouling was investigated. The result showed that pre-depositing adsorbents on membrane could not only reduce membrane fouling but also enhance HA removal. The flux was related to the adsorbent dosage and the optimal dosage for pre-deposition was $35.0g/m^2$. The dissolved organic carbon (DOC) removal of HA was 38.3%, 67.3% and 41.1% respectively when pre-deposited $35.0g/m^2$ $FeO_xH_y$, $MnFe_2O_4$ and $Fe_3O_4$ on membrane. Different adsorption effect of adsorbents on HA contributed to increasing of the flux at different level. Zeta potential of three adsorbents all decreased after adsorbed HA. The adsorption capacity of the three adsorbents was $FeO_xH_y$ > $MnFe_2O_4$ > $Fe_3O_4$. Atomic Force Microscopy (AFM) measurement showed the thickness of pre-deposition layers formed by different adsorbents was different. The scanning electron microscope (SEM) detection showed the morphology and compactness of pre-deposition layers formed by different adsorbents was different.

• 멤브레인
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• 제21권4호
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• pp.351-359
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• 2011

For advanced drinking water treatment of high turbidity water, we used the hybrid process that was composed of photocatalyst packing in space of between outside of multi-channel ceramic microfiltration membrane and membrane module inside. Photocatalyst was polypropylene (PP) beads coated $TiO_2$ powder by CVD (chemical vapor deposition) process. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, standard NOM solution was prepared with humic acid and kaolin. Water-back-flushing of 10 sec was performed per every period of 10 min to minimize membrane fouling. Resistance of membrane fouling ($R_f$) increased and J decreased as concentration of humic acid changed from 2 mg/L to 10 mg/L, and finally the highest total permeate volume ($V_T$) could be obtained at 2 mg/L. Then, treatment efficiency of turbidity and $UV_{254}$ absorbance were above 96.4% and 78.9%, respectively. As results of treatment portions by membrane filtration, photocatalyst adsorption, and photo-oxidation in (MF), (MF + $TiO_2$), (MF + $TiO_2$ + UV) processes, turbidity was treated little by photocatalyst adsorption, and photo-oxidation. However, treatment portions of $UV_{254}$ absorbance by adsorption (MF + $TiO_2$) and photo-oxidation (MF + $TiO_2$ + UV) at humic acid of 4 mg/L and 6 mg/L were above 9.0, 9.5 and 8.1, 10.9%, respectively.

• Korean Membrane Journal
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• 제11권1호
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• pp.21-28
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• 2009

We investigated the effect of organic materials on membrane fouling in advanced drinking water treatment by a hybrid module packed with granular activated carbon (GAC) outside multi-channel ceramic microfiltration membrane. Synthetic water was prepared with humic acid and kaolin to simulate natural water resouces consisting of natural organic matter and inorganic particles. Kaolin concentration was fixed at 30 mg/L and humic acid was changed as 2~10 mg/L to inspect the effect of organic matters. Periodic back-flushing using permeate water was performed for 10 sec per filtration of 10 min. As a result, both resistance of membrane fouling (Rf) and permeate flux (J) were influenced highly by concentration of humic acid. It proved that NOM like humic acid could be an important factor on membrane fouling in drinking water treatment. Turbidity and UV254 absorbance were removed up to above 97.4% and 59.2% respectively.

• 멤브레인
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• 제27권1호
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• pp.68-76
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• 2017

고강도, 내약품성, 무독성, 내연소성의 장점을 가지고 있는 PVdF (polyvinylidene fluoride) 나노섬유로 기공이 $0.4{\mu}m$ 평막을 제조한 후, 부직포와 평막으로 나권형 모듈을 제작하였다. 용존유기물의 흡착 제거를 위한 입상 활성탄(GAC, granular activated carbon) 흡착 컬럼과 자체 제작한 나권형 모듈로 혼성 수처리 공정을 구성하였다. 카올린과 휴믹산으로 조제한 모사 용액을 대상으로, 처리수를 재순환하는 경우와 배출하는 경우 각각 GAC 충진량의 영향을 알아보았다. 여과실험 후 물 역세를 하여 회복률과 여과저항을 계산하였다. 또한, 탁도와 $UV_{254}$ 흡광도를 측정하여 GAC의 흡착 효과를 고찰하였다. 그 결과, 처리수를 재순환하는 경우와 배출하는 경우 모두 탁도 처리율에는 GAC 충진량의 영향이 없었다, 하지만 GAC의 $UV_{254}$ 흡광도 처리율이 처리수를 순환하는 경우 0.7~3.6%이었는데, 처리수를 배출하는 경우 3.2-5.7%로 증가하였다. 처리수를 순환하는 경우 GAC의 충진량이 증가함에 따라, 가역적 여과저항($R_r$)과 비가역적 여과저항($R_{ir}$)은 감소하는 경향을 보였다. 그러나 총여과저항($R_t$)은 거의 일정하였고, 물 역세 회복률($R_b$)은 다소 증가하는 경향을 보였다.