• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.364-369
• /
• 2012

The development of solar thermal energy used adsorption desalination technology have been examined as a viable option for supplying clean energy. In this study, the modelling of the main devices for solar thermal energy used and adsorption desalination system was introduced. Silica gel type adsorption desalination system is considered to be a promising low-temperature heat utilization system. The design is divided into three parts. First, the evaporator for the vaporization of the tap water is designed, and then the reactor for the adsorption and release of the steam is designed, followed by the condenser for the condensation of the fresh water is designed. In addition, new features based on the energy balance are also included to design absorption desalination system. In this basic research, One-bed(reactor) adsorption desalination plant that employ a low-temperature solar thermal energy was proposed and experimentally studied. The specific water yield is measured experimentally with respect to the time controlling parameters such as heat source temperatures, coolant temperatures, system switching and half-cycle operational times. Desalination is processes that permeate our daily lives, but It requires substantial energy input, powered either from electricity or from thermal input. From the environmental and sustainability perspecives, innovative thermodynamic cycles are needed to produce the above-mentioned useful effects at a lower specific energy input. This article describes the development of adsorption cycles for the production of desalting effects. We want that this adsorption system can be driven by low temperature heat sources at 60 to $80^{\circ}C$, such as renewable, solar thermal energy.

• Journal of the Korean Solar Energy Society
• /
• v.33 no.6
• /
• pp.39-46
• /
• 2013

This work introduces a simple one-reactor adsorption desalination system that harnesses low temperature heat sources (solar energy, waste heat), which has been experimentally studied to elicit the most suitable design parameters and operating conditions. The design process of the system was divided into three parts to reflect the operating principle of desalination technology with application of adsorption processes. First, the evaporator for the vaporization of saline water was designed, then the reactor for the adsorption and release of the steam, followed by the condenser for condensation of the fresh water. The specific water yield is measured experimentally with respect to the time while controlling parameters such as heat source temperatures, coolant temperatures, system switching and half-cycle operational times. The present system well demonstrates the applicability of silica gel in relation to adsorption technologies that utilize low temperature heat sources ranging from 60 to $80^{\circ}C$, such as solar energy and waste heat.

• 한국태양에너지학회:학술대회논문집
• /
• 2011.04a
• /
• pp.204-209
• /
• 2011

According to the environment report of UN, korea was classified as potable water shortage countries. Approximately 71% of the Earth's surface is covered by ocean. However, it is difficult to use for industry of residential purpose without a certain processing. The development of solar and waste-heat used absorption desalination technology have been examined as a viable option for supplying clean energy. In this study, the modelling of the main devices for solar and waste-heat used and adsorption desalination system was introduced. The design is divided into three parts. First, the evaporator for the vaporization of the top water is designed, and then the reactor for the adsorption and release of the steam is designed, followed by the condenser for the condensation of the fresh water is designed. In addition, new features based on the energy balance are also included to design absorption desalination system. In this basicresearch, One-bed(reactor) adsorption desalination plant that employ a low-temperature solar and waste energy was proposed and experimentally studied. The specific water yield is measured experimentally with respect to the time controlling parameters such as heat source temperatures, coolant temperatures, system switching and half-cycle operational times.

• Applied Chemistry for Engineering
• /
• v.30 no.4
• /
• pp.472-478
• /
• 2019

A stable desalination method of the hardness substance such as $Ca^{2+}$ by controlling the total charge (TC) supplied to the membrane capacitive deionization (MCDI) cell was studied. The adsorption (1.5 V) and desorption (0.0 V) were repeated 30 times while varying the TC in the adsorption process. The concentration and pH of effluent, adsorption and desorption amounts, current densities and cell potentials were analyzed in the desalination process. The maximum allowable charge (MAC) of the carbon electrode used in MCDI cell was measured to be 46 C/g. As a result of operation at TC (40 C/g) below the MAC value, electrode reactions did not occur, resulted in the stable desalination characteristics for a long-term operation. When operating at TCs (50, 60 C/g) above the MAC value, however, the concentration and pH of effluent varied greatly. Also, the scale was formed on the electrode surface due to electrode reactions, and the electric resistance of the cell gradually increased. It was thus concluded that it is possible to remove stably the hardness substance without any electrode reactions by controlling the charge supplied to MCDI cell during the adsorption process.

• Applied Chemistry for Engineering
• /
• v.21 no.1
• /
• pp.87-92
• /
• 2010

Desalination experiments were carried out with two types of cell configuration; a CDI cell constructed with carbon electrodes only and a membrane capacitive deionization (MCDI) cell having a cation-exchange membrane on the cathode surface. The salt removal rate and desalination efficiencies increased linearly with increasing the cell potential. Although the same carbon electrodes were used in the desalination experiments, the MCDI cell showed higher salt removal efficiency than that of the CDI cell. The amount of salt removal for the MCDI cell was enhanced by 33.1~135% compared to the CDI cell, depending on the applied cell potential in the range of 0.8~1.2 V. In addition, the current efficiency for the MCDI cell was about 80%, whereas the efficiency was under 40% for the CDI cell. The higher salt removal efficiency in the MCDI cell was attributed to the fact that ions were selectively transported between the electric double layer and the bulk solution in the MCDI cell configuration.

• Korean Chemical Engineering Research
• /
• v.58 no.3
• /
• pp.466-473
• /
• 2020

Fabric current collector can be a promising electrode material for Capacitive Deionization (CDI) system that can achieve energy-efficient desalination of water. The one of the most attractive feature of the fabric current collector is its high tensile strength, which can be an alternative to the low mechanical strength of the graphite foil electrode. Another advantage is that the textile properties can easily make shapes by simple cutting, and the porosity and inter-fiber space which can assist facile flow of the aqueous medium. The fibers used in this study were made of woven structures using a spinning yarn using conductive LM fiber and carbon fiber, with tensile strength of 319 MPa, about 60 times stronger than graphite foil. The results were analyzed by measuring the salt removal efficiency by changing the viscosity of electrode slurry, adsorption voltage, flow rate of the aqueous medium, and concentration of the aqueous medium. Under the conditions of NaCl 200 mg/L, 20ml/min and adsorption voltage 1.5 V, salt removal efficiency of 43.9% in unit cells and 59.8% in modules stacked with 100 cells were shown, respectively. In unit cells, salt removal efficiency increases as the adsorption voltage increase to 1.3, 1.4 and 1.5 V. However, increasing to 1.6 and 1.7 V reduced salt removal efficiency. However, the 100-cell-stacked module showed a moderate increase in salt removal efficiency even at voltages above 1.5 V. The salt removal rate decreased when the flow rate of the feed was increased, and the salt removal rate decreased when the concentration of the feed was increased. This work shows that fabric current collector can be an alternative of a graphite foil.

• Applied Chemistry for Engineering
• /
• v.23 no.5
• /
• pp.474-479
• /
• 2012

Possibility of the selective removal of $Ca^{2+}$ ions from a mixed solution of $Na^{+}$ and $Ca^{2+}$ ions using membrane capacitive deionization (MCDI) was investigated. Adsorption equilibrium experiments were conducted to determine the selectivity of the CMX cation-exchange membrane toward $Ca^{2+}$ ions. In addition, desalination experiments for a mixed solution (5 meq/L NaCl + 2 meq/L $CaCl_{2}$) were performed using an MCDI cell. The adsorption equilibrium of CMX membrane showed that the equivalent fraction of $Ca^{2+}$ ions in the solution and the CMX membrane were 28.6 and 87.2%, respectively, which indicates the CMX membrane's high selectivity toward $Ca^{2+}$ ions. Desalination experiments were performed by applying a constant current to the MCDI cell until the cell potential reached 1.0 V. The amount of ions adsorbed did not significantly change as the applied current was changed. However, the equivalent fractions of $Ca^{2+}$ ions among the adsorbed ions were inversely proportional to the applied currents: 81.4, 78.4, 77.0, and 74.5% at 200, 300, 500, and $700\;A/m^{2}$ of applied current density, respectively. This result is attributed to the increased fraction of $Ca^{2+}$ ions adsorbed by the CMX membrane at lower applied current densities.

• Membrane and Water Treatment
• /
• v.6 no.2
• /
• pp.161-172
• /
• 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.

• Journal of agriculture & life science
• /
• v.46 no.2
• /
• pp.169-178
• /
• 2012

This study was aimed at providing optimal water treatment processes based on various required water quality for utilization of the Saemangeum lake water as water supply alternatives to this area. Various water treatment methods were considered for investigation there characteristics, pollution removal rate, pros and cons in order to select appropriate water treatment processes satisfying the required water quality for different purposes. As results, the FDA system for SS, turbidity, BOD removals, UV treatment for coliform, BOD removals, FNR process for T-N, T-P removals, and ECRS process for desalination purpose were found to be better methods in senses of removal efficiency, operation and maintenance. Case studies were provided with cost analysis for field applications in the Saemangeum area.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.4 no.4
• /
• pp.113-125
• /
• 1984

Water supply has been mainly dependent on the construction of the dams in Korea. It is difficult, however, to continue to construct dams for many reasons, such as the decrease of construction sites, the increase of construction costs, the compensation of residents in flooded areas, and the environmental effects. Water demands have increased and are expected to continue increasing due to the concentration of people in the cities, the rise of the living standard, and rapid industrial growth. It is acutely important to find countermeasures such as development of ground water, desalination, and recycling of waste water to cope with increasing water demands. Recycling waste water includes all means of supplying non-potable water for their respective usages with proper water quality which is not the same quality as potable water. The usages of the recycled water include toilet flushing, air conditioning, car washing, yard watering, road cleaning, park sprinkling, and fire fighting, etc. Raw water for recycling is obtained from drainage water from buildings, toilets, and cooling towers, treated waste water, polluted rivers, ground water, reinfall, etc. The water quantity must be considered as well as its quality in selecting raw water for the recycling. The types of recycling may be classified roughly into closed recycle systems and open recycle systems, which can be further subdivided into individual recycle systems, regional recycle systems and large scale recycle system. The treatment methods of wastewater combine biochemical and physiochemical methods. The former includes activated sludge treatment, bio-disc treatment, and contact aeration treatment, and the latter contains sedimentation, sand filtration, activated carbon adsorption, ozone treatment, chlorination, and membrane filter. The recycling patterns in other countries were investigated and the effects of the recycling were divided into direct and indirect effects. The problems of water reuse in recycle patterns were also studied. The problems include technological, sanitary, and operational problems as well as cost and legislative ones. The duties of installation and administrative organization, structural standards for reuse of water, maintenance and financial disposal were also studied.