• Membrane Journal
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• v.31 no.5
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• pp.315-326
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• 2021

Lithium ion battery (LIB) demands increase every year globally to reduce the burden on fossil fuels. LIBs are used in electric vehicles, stationary storage systems and various other applications. Lithium is available in seawater, salt lakes, and brines and its extraction using environmentally friendly and inexpensive methods will greatly relieve the pressure in lithium mining. Membrane separation processes, mainly nanofiltration (NF), is an effective way for the separation of lithium metal from solutions. Electrodialysis and electrolysis are other separation processes used for lithium separation. The process of reverse osmosis (RO) is already a well-established method for the desalination of seawater; therefore, modifying RO membranes to target lithium metals is an excellent alternative method in which the only bottleneck is the interfering presence of other metal elements in the solution. Selectively removing lithium by finding or developing suitable NF membranes can be challenging, but it is nonetheless an exciting area of research. This review discusses in detail about lithium recovery via nanofiltration, electrodialysis, electrolysis and other processes.

• Journal of Soil and Groundwater Environment
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• v.28 no.3
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• pp.12-28
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• 2023

Each national groundwater monitoring well showed distinct change patterns in groundwater levels and electrical conductivity (EC) in the Nakdong River Estuary, implying different external forces (EFs) on each well. According to the annual average data in 1997-2020, seawater was invaded into Well C. The desalination rate of -1,062 µS/cm/year represents the adaptive capacity of the well to seawater intrusion. The water levels and EC in Well E responded to precipitation, indicating the low absorptive capacity to climate changes. Meanwhile, Well B showed constant increases in water levels, suggesting that problems by rising groundwater should be considered in the study area where confined aquifers are overlaid by clay aquitards. The other wells showed consistent water levels and EC, indicating resilience to EFs. Here, resilience is the capacity of a well to resist changes by EFs, including the absorptive and adaptive capacity. The resilience of Wells E and F to climate changes was quantitatively compared using a resilience cost (RC). The RC showed Well F was more resilient than Well E, and the bedrock aquifer was more resilient than the alluvium aquifer, supporting the usefulness of RC. The resilience assessment against EFs (e.g., changes in land use and climate) helps sustainable groundwater management.

• Membrane Journal
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• v.27 no.4
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• pp.291-312
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• 2017

Seawater desalination is currently considered to be one of the primary technologies to resolve the global water scarcity problem. A basic understanding of membrane filtration phenomena is significant not only for further technological development but also for integrated design, optimal control, and long-term maintenance. In this vein, the present work reviews the major transport and filtration models, specifically related to reverse osmosis phenomena, provides theoretical insights based on statistical mechanics, and discusses model-based physical meanings as related to their practical implications.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.225-229
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• 2001

In Korea, an advanced reactor system of 330MWt power called SMART (System integrated Modular Advanced ReacTor) is being developed by KAERI to supply energy for seawater desalination as well as electricity generation. A shielding design of the SMART core with 49 CEDM is established by a two-dimensional discrete ordinates radiation transport analyses. The DORT two-dimensional discrete ordinates transport code is used to evaluate the SMART shielding designs. Three axial regions represent the SMART reactor assembly, each of which is modeled in the R-Z geometry. The BUGLE-96 library is used in the analyses, which consists of 47 neutron and 20 gamma energy groups. The results indicate that the maximum neutron fluence at the bottom of reactor vessel is $5.89 {\times} 10^{17}\;n/cm^2$ and that on the radial surface of reactor vessel is $4.49 {\times} 10^[16}\;n/cm^2$. These results meet the requirement, $1.0 {\times} 10^{20}\;n/cm^2$, in 10 CFR 50.61 and the integrity of SMART reactor vessel during the lifetime of the reactor is confirmed.

• Membrane and Water Treatment
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• v.1 no.3
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• pp.193-206
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• 2010

Organic fouling and biofouling pose a significant challenge to the membrane filtration process. Photocatalysis-membrane hybrid system is a novel idea for reducing these membranes fouling however, when $TiO_2 photocatalyst nanoparticles are used in suspension, catalyst recovery is not only imposes an extra step on the process but also significantly contributes to increased membrane resistance and reduced permeate flux. In this study, $TiO_2$ photocatalyst has been immobilized by coating on the microfiltration (MF) membrane surface to minimize organic and microbial fouling. Nano-sized $TiO_2$ was first synthesized by a sol-gel method. The synthesized $TiO_2$ was coated on a Poly Vinyl Difluoride (PVDF) membrane (MF) surface using spray coating and dip coating techniques to obtain hybrid functional composite membrane. The characteristics of the synthesized photocatalyst and a functional composite membrane were studied using numerous instruments in terms of physical, chemical and electrical properties. In comparison to the clean PVDF membrane, the $TiO_2$ coated MF membrane was found more effective in removing methylene blue (20%) and E-coli (99%).

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.343-350
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• 2016

Membrane distillation (MD) is a novel separation process that have drawn attention as an affordable alternative to conventional desalination processes. However, membrane fouling and pore wetting are issues to be addressed prior to widespread application of MD. In this study, the influence of ultrasonic irradiation on fouling and wetting of MD membranes was investigated for better understanding of the MD process. Experiments were carried out using a direct contact membrane distillation apparatus Colloidal silica was used as a model foulants in a synthetic seawater (35,000 mg/L NaCl solution). A vibrator was directed attached to membrane module to generate ultrasonic waves from 25 kHz (the highest energy) to 75 kHz (the lowest energy). Flux and TDS for the distillate water were continuously monitored. Results suggested that ultrasonic irradiation is effective to retard flux decline due to fouling only in the early stage of the MD operation. Moreover, wetting occurred by a long-term application of ultrasonic rradiation at 75 kHz. These results suggest that the conditions for ultrasonic irradiation should be carefully optimized to maximize fouling control and minimize pore wetting.

• Laser Solutions
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• v.14 no.1
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• pp.19-24
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• 2011

This work reports the results for laser shock peening of duplex stainless steel (22% Chromium - 5% Nickel) using a pulsed Nd:YAG laser (wavelength = 532nm, pulse width = 8ns). for the application to high-capacity pumps for seawater desalination plants. By properly selecting the process parameters such as laser intensity of 10GW/$cm^2$, laser pulse density of 75pulse/$mm^2$, and $100{\mu}m$ thick aluminum foil as an absorbent coating layer, the surface hardness of duplex stainless steel could be enhanced by 26%, from 256HV to 323HV with little changes in surface morphology and roughness. The depth of laser shock peened layer was measured to be around 2mm. The large enhancement of surface hardness is considered to have high practical importance in minimizing abrasive and corrosive deterioration of pump parts.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.6
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• pp.413-420
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• 2019

Pretreatment system of desalination process using seawater reverse osmosis(SWRO) membrane is the most critical step in order to prevent membrane fouling. One of the methods is coagulation-UF membrane process. Coagulation-UF membrane systems have been shown to be very efficient in removing turbidity and non-soluble and colloidal organics contained in the source water for SWRO pretreatment. Ferric salt coagulants are commonly applied in coagulation-UF process for pretreatment of SWRO process. But aluminum salts have not been applied in coagulation-UF pretreatment of SWRO process due to the SWRO membrane fouling by residual aluminum. This study was carried out to see the effect of residual matal salt on SWRO membrane followed by coagulation-UF pretreatment process. Experimental results showed that increased residual aluminum salts by coagulation-UF pretreatment process by using alum lead to the decreased SWRO membrane salt rejection and flux. As the salt rejection and flux of SWRO membrane decreased, the concentration of silica and residual aluminum decreased. However, when adjusting coagulation pH for coagulation-UF pretreatment process, the residual aluminum salt concentration was decreased and SWRO membrane flux was increased.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.423-433
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• 2020

Direct current (DC) electric fields have been used for electro-osmotic dewatering. Under DC conditions, however, the electrical contact resistance between the electrode and the dewatering material increases considerably during the process of dewatering. Such a circumstance hinders the continuation of effective electro-osmotic dewatering. To reduce this hindrance, an applied pulse electric field with periodic reversals of the electrode polarity should improve electro-osmotic dewatering. In this study, electro-osmotic dewatering under pulse conditions was experimentally investigated for electrode polarity reversals. During the dewatering process, the pulse electric field was able to reduce the hindrance caused by the DC, resulting in an increased final dewatered amount relative to that under a DC electric field. For a constant applied voltage, the reversed polarity condition, under which the electric current passing through the material was almost unchanged with time, yielded the maximum final dewatered amount. This technique can be used to enhance drainage from a water storage facility during a period of extreme drought and the seawater desalination plants using reverse osmosis in drought stricken coastal regions.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.437-454
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• 2021

This study investgates Korean water technology through the water market perspective and analyses its competitiveness. Based on the water technology classification, water technology competitiveness is analysed through the technological influence index and market dominance index which are based on the extracted water technology patents from the US, Europe, Korea, and Japan for the last decade. As a result, the Korean water technology patents were lack in influence and competitiveness in global market considering the large volume of patents. There are two most tech-influential industries in Korea; manufacturing industry consisting pipes, sterilization, disinfection, and advanced water purification equipment, and construction industry including seawater desalination and water resource development. Due to the domestic usage of the patents, the Korean water technology patents scored low in global market PFS(Patent Family Size) index compared to their CPP(Cites Per Patent) index. The study is meaningful in a way that the analysis on Korean water technology competitiveness using water technology classification system and patent analysis was conducted based on the perspective of the global water market.