• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.3
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• pp.193-198
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• 2013

In general, boron recovery of 40-90% could be achieved by Reverse Osmosis (RO) membranes in neutral pH condition. As an emerging technology, Forward Osmosis (FO) membrane has attracted growing interest in wastewater treatment and desalination. The objective of this study is to evaluate the possibility of the boron removal in radioactive liquid waste by FO. In this study, the performance of FO was investigated to remove boron in the simulated liquid waste as the factors such as pH, osmotic pressure, ionic strength of solution, etc. The pH of feed solution is a major operating parameter which strongly influences to the permeation of boron and more than 80% of boron content can be separated when conducted at pH values less than 7. The water flux is not influenced but the boron flux and permeation rate tends to decrease in the low salt concentration of 1,000 mg/L. The boron flux increases linearly, but the permeation ratio of reducing boron is nearly constant even with changes in the draw solution concentration.

• Membrane Journal
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• v.31 no.1
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• pp.16-34
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• 2021

Water supplies are decreasing in comparison to increasing clean water demands. Using nanofiltration is one of the most effective and economical methods to meet the need for clean water. Common methods for desalination are reverse osmosis and nanofiltration. However, pristine membranes lack the essential features which are, stability, economic efficiency, antibacterial and antifouling performances. To enhance the properties of the pristine membranes, graphene oxide (GO) is a promising and widely researched material for thin film composites (TFC) membrane due to their characteristics that help improve the hydrophilicity and anti-fouling properties. Modification of the membrane can be done on different layers. The thin film composite membranes are composed of three different layers, the top filtering active thin polyamide (PA) layer, supporting porous layer, and supporting fabric. Forward osmosis (FO) process is yet another energy efficient desalination process, but its efficiency is affected due to biofouling. Incorporation of GO enhance antibacterial properties leading to reduction of biofilm formation on the membrane surface. Pressure retarded osmosis (PRO) is an excellent process to generate clean energy from sea water and the biofouling of membrane is reduced by introduction of GO into the active layer of the TFC membrane. Different modifications on the membranes are being researched, each modification with its own advantages and disadvantages. In this review, modifications of nanofiltration membranes and their composites, characterization, and performances are discussed.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.235-239
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• 2001

In recent years, as Chemical Mechanical Planarization(CMP) has been routinely utilized in integrated circuit(IC) fabrication, the consumption of slurry, main consumable in a CMP process, is greatly increased. Thus the reprocess of CMP slurries has been actively considered in the industry to reduce cost-of-consumable (COC). The main purpose of this study was to recycle the used oxide slurry using filters as a new method. As a result, Ultra Fine(UF) Filter could distinguish silica from the used oxide slurry and Reverse Osmosis(RO) Filter could distinguish Deionized(DI) Water and chemistry from chemistry solution. The tetraethylorthosilicate removal rate was almost the same as the number of recycle polishing was increased, when it was modified by slightly adding new SS-12 slurry. The microscratch didnt found as the number of recycle polishing was increased.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.5
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• pp.475-481
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• 2009

Real-coded genetic algorithm(RCGA) has better performances than conventional genetic algorithm about dealing with a large domain, the precision and the constrain problem. Also the RCGA has advantage of operation time because it doesn't have to following about decoding operation. In this paper the ranges of PID gains are limited based on Ziegler-Nichols method to consider a long operation time problem that is the main problem of genetic algorithm. Result shows proposed method represents better performance without ignored about result of ZN tuning method and reduces the calculation time.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.7-12
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• 1993

Preparation of asymmetric polyimide membranes by the phase inversion process was investigated to develop ultrafiltration, reverse osmosis and pervaporation membranes for organic solutions, using a commercially available solvent-soluble polymaide. The influences of the various factors such as the composition of a cast solution, casting conditions, gelating solutions and others on membrane structure and performance were studied in detail, and it was made clear that a wide variety of asymmetric polyimide membranes ranging from UF to RO for organic solutions could be prepared from the aromatic polyimide used. It was also found that the chemical stability and separation performance of the asymmetric polyimide membranes could be improved by annealing in a liquid or a vacuum at above 200$\circ$. The membrane annealed at 300$\circ$ in a vacuum exhibited the separation factor $\alpha(H_2O/EtOH)$ of 900 with the flux of 1.0 kg/$m^2\cdot h$ at 60$\circ$C for an aqueous ethanol solution of 95 vol%.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.836-839
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• 2009

중소형 폐기물소각설비의 저압 저질의 포화증기를 이용한 폐열발전용 용수처리에 관한 연구를 수행 하였다. 기존 소각설비에 적용된 강산성 이온교환수지형 연수기에 역삼투압 멤브레인 처리와 강염기성 이온교환수지형 용수처리를 연결하여 보일러 용수를 처리한 결과, KS B6209의 30 $kg/cm_2$ 증기 압력의 보일러 용수기준에는 적합하였고, 증기의 비체적으로 증기 농도로 환산하면. 역삼투압법처리에 의한 방법보다는 강염기성이온교환수지형 용수처리를 연계 처리한 결과가 중소형폐기물소각설비의 저압증기터빈발전에 보다 적합한 것으로 나타났다.

• Environmental Engineering Research
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• v.20 no.3
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• pp.285-289
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• 2015

Complicated and expensive seawater desalination technology is a big challenge in boron removal process. Conventional seawater desalination process of coagulation utilized for pre-treatment is difficult to remove boron. Boron can be removed more effectively in Reverse Osmosis (RO) process than any other processes. In this study, a coagulant with the name Mineral Cluster was examined its boron removal ability. Boron removal efficiency of Mineral Cluster depended on pH value and Mineral Cluster dosage. Desalination process combines the pre-treatment process with Mineral cluster diluted at the ratio of 1:2500 and the RO membrane process. The original sea water could be desalinated to drinking water quality, 1 mg/L, without any pH adjustments. Therefore, if the Mineral cluster is added without any other chemicals for adjusting pH, the desalination process would be much safer, efficient and economical.

• Environmental Engineering Research
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• v.16 no.4
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• pp.227-230
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• 2011

Seawater desalination technology is a complicated and expensive process. Besides salt removal from seawater, thesignificant problem that needs to be solved is boron removal. Boron removal is difficult so it is a considerable challenge for the desalination process. The main technology of this process is reverse osmosis (RO). RO can remove salt and boron more effectively than other technologies. In a conventional seawater desalination process, coagulant is utilized for pre-treatment but it is difficult to remove boron through this stage. In this study, a coagulant called Mineral Cluster was examined for boron removal. Therefore, Mineral Cluster can be considered a potential coagulant for boron removal in seawater desalination technology.

• Membrane and Water Treatment
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• v.3 no.3
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• pp.181-200
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• 2012

At present water crisis is not an issue of scarcity, but of access. There is a growing recognition of the need for increased access to clean water (drinkable, agricultural, industrial use). An encouraging number of innovative technologies, systems, components, processes are emerging for water-treatment, including new filtration and disinfectant technologies, and removal of organics from water. In the past decade many methods have been developed. The most important membrane-based water technologies include reverse osmosis (RO), ultrafiltration (UF), microfiltration (MF), and nanofiltration. Beside membrane based water-treatment processes, other techniques such as advanced oxidation process (AOP) have also been developed. Some unconventional water treatment technology such as magnetic treatment is also being developed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.180-183
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• 2003

제주지역 하수종말처리장에서 발생하는 방류수(2차 처리수)를 재이용함으로써 지하수에 편중된 제주도의 용수 이용패턴을 다원화하는 대체수자원으로 활용하기 위하여 2001년 6월부터 하수처리장 방류수 재이용 방안연구를 실시하였다. 제주도내에서 운영 중인 3개 하수종말처리장의 방류수에 대한 장기적인 수질검사 결과, 염소이온 함량이 높아 재처리를 하지 않은 상태로 재이용 하기는 곤란한 것으로 파악되었다. 따라서, 재처리를 위한 최적의 공정을 선정하기 위해 pilot test를 실시한 결과, 방류수를 MF(정밀여과)막 전처리 ＋ RO(역삼투)막 처리의 재처리 공정으로부터 재처리된 물(3차 처리수)의 수질은 먹는물로 사용하더라도 전혀 문제가 없을 만큼 깨끗하게 처리되었다. 따라서 방류수 배출량이 많은 제주시 도두 하수처리장과 서귀포 보목 하수처리장의 방류수를 재처리하여 비음용 생활용수, 골프장 관개 수용수, 농업용수, 지하수 인공 함양용수 등으로 재이용하는 방안을 제시하였다.