• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.219-224
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• 2021

Ion flotation is an efficient method to remove metal ions from aqueous solution. In this work, ion flotation was applied to calcium removal from aqueous solution. The parameters used included sodium stearate (SS) and sodium dodecyl sulfate (SDS) as collectors, 1-butanol and 1-propanol as frothers, pH, and air-flow rate. An L16 orthogonal array was chosen according to the mentioned factors and levels, and experimental tests were conducted according to the Taguchi orthogonal array. The results showed that all of the factors except one had significant effect on the flotation performance. The percentage contribution of parameters showed that type of frother and type of collector made the greatest (43.14%) and the lowest (9.86%) contribution, respectively. In optimal conditions, the recovery of Ca (II) ion was 45.67%. Also, the results illustrated that the Taguchi method could predict calcium removal from aqueous solution by ion flotation with 2.63%. This study showed that the use of ion flotation was an effective method for Ca (II) ion removal from aqueous solution.

• Journal of Environmental Science International
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• v.24 no.1
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• pp.47-53
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• 2015

Removal characteristics of Cu(II) ions by solid-phase extractant immobilized D2EHPA and TBP in PVC were investigated. Cu(II) ion concentrations in the solution and removal capacity of Cu(II) ion according to operation time were compared. The lower the initial concentration of Cu(II) ion in aqueous solution was, the removal capacity of Cu(II) ion by solid-phase extractant was increased relatively. The bigger the initial concentration of Cu(II) ion was, the removal capacity of Cu(II) ion was increased relatively. The pseudo-second-order kinetics according to operation time was showed more satisfying results than the pseudo-first-order kinetics for the removal velocity of Cu(II) ion. The removal capacity of Cu(II) ion was 0.025 mg/g in aqueous solution of pH 2, but the removal capacity of Cu(II) ion was increased to 0.33 mg/g mg/g in aqueous solution of pH 4 according to increasing pH.

• Journal of the Korean Society of Safety
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• v.4 no.1
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• pp.15-24
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• 1989

The transport of Chromium(Vl) ion from waste water throughl the liquid surfactant membrane containing tri-n-octylamine as a carrier, was analyzed by a slab model and was investigated through experiments. For the experiment of membrane stability, concentrations of surfactant and liquid parafnn oil were analyzed. Extraction euperiments were carried out to observe the effect of system variables, such as stirring speed, concentration of carrier, and NaOH in internal aqueous phase, and concentrations of H$_2$SO$_4$and initial chromium(VI) ion in external aqueous phase at $25^{\circ}C$. It is concluded that the most stable formation of liquid membrane emulsion was obtained when surfactant concentration is above 3 wt. ％ and liquid parafnn oil concentration is 50 vol. ％. The transport of chromium(VI) ion in bacth extractor increased with increasing carrier concentration, the volume ratio of emulsion to external aqueous phases, and initial concentration of chromium(VI) ion under the optimum stirring speed of chromium(VI) ion below 2 ppm. The theoretical equation on the transport of chromium(Vl) ion agreed well with the experimental results.

• Korean Journal of Materials Research
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• v.26 no.9
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• pp.498-503
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• 2016

The characteristics of aqueous lithium recovery by ion exchange were studied using three commercial cation exchange resins: CMP28 (porous type strong acid exchange resin), SCR-B (gel type strong acid exchange resin) and WK60L (porous type weak acid exchange resin). CMP28 was the most effective material for aqueous lithium recovery; its performance was even enhanced by modifying the cation with $K^+$. A comparison to $Na^+$ and $H^+$ form resins demonstrated that the performance enhancement is reciprocally related to the electronegativity of the cation form. Further kinetic and equilibrium isotherm studies with the $K^+$ form CMP28 showed that aqueous lithium recovery by ion exchange was well fitted with the pseudo-second-order rate equation and the Langmuir isotherm. The maximum ion exchange capacity of aqueous lithium recovery was found to be 14.28 mg/g and the optimal pH was in the region of 4-10.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.615-621
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• 2013

Membrane characterization methods for aqueous redox flow batteries aqueous RFBs were modified for non-aqueous RFBs. The modified characterization methods, such as ion exchange capacity, transport number, permeability and single cell test, were carried out to evaluate commercial membranes in non-aqueous electrolyte. It was found that columbic efficiency and energy efficiency in a single cell test were dependent on the ion selectivity of commercial anion exchange membranes. Neosepta AHA anion exchange membrane showed the anion transport number of 0.81, which is a relatively low ion selectivity in non-aqueous electrolyte, however, exhibited 92% of coulombic efficiency and 86% of energy efficiency in a single cell test. It was also found that a porous membrane without ion selectivity is suitable for a non-aqueous redox flow battery at a high current density.

• Journal of Environmental Science International
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• v.9 no.2
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• pp.159-164
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• 2000

For the purpose of development of a liquid membrane permeator which separates metal ions from aqueous solutions continuously and effectively, a continuous membrane permeator with the membrane solution trapped between extraction and stripping phases by two micro-porous hydrophilic films was manufactured. Experimental researches on the separation of zinc ion from aqueous solutions were performed in the liquid membrane permeator with 30 vol % D2EHPA solution in kerosine as liquid membrane. As results, the liquid membrane permeator separates zinc ion from aqueous solutions continuously and effectively in the wide range of operating conditions. A simple mass transfer rate model using equilibrium constant of the extraction reaction for the system used were proposed, and the model was compared with experimental results of separation of zinc ion in the permeator. And the effects of operating factors, such as space time, pH of extraction solution, extraction temperature, on the separation rate of zinc ion in the permeator were experimentally examined.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.438-444
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• 2011

Magnesium is one of the abundant natural resources in the earth crust and seawater, which is directly related to various organisms activities interconnecting with water-rock system. In aqueous system, magnesium is known to predominantly exist in the form of $Mg^{2+}$ ion which is verified in its $E_h-pH$ diagram. When it is at equilibrium in aqueous system, temperature takes an essential role to complete equilibrium states. This study represents the change of the stable region of magnesium ion according to temperature, and how the consequences would affect aquatic organisms. It was revealed that there is a noticeable tendency shrinking the stable region of magnesium ion in a diagram as temperature increases, and as a result, aquatic bio-species presumably have difficulties to absorb the nutrient. Also, it was considered that the water system would be acidified by decreasing alkalinity.

• Electronics and Telecommunications Trends
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• v.39 no.1
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• pp.83-94
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• 2024

There have been continuous requirements for developing more reliable energy storage systems that could address unsolved problems in conventional lithium-ion batteries (LIBs) and thus be a proper option for large-scale applications like energy storage system (ESS). As a promising solution, aqueous metal-ion batteries (AMIBs) where water is used as a primary electrolyte solvent, have been emerging owing to excellent safety, cost-effectiveness, and eco-friendly feature. Particularly, AMIBs adopting mutivalence metal ions (Ca²⁺, Mg²⁺, Zn²⁺, and Al³⁺) as mobile charge carriers has been paid much attention because of their abundance on globe and high volumetric capacity. In this research trend review, one of the most popular AMIBs, zinc-ion batteries (ZIBs), will be discussed. Since it is well-known that ZIBs suffer from various (electro) chemical/physical side reactions, we introduce the challenges and recent advances in the study of ZIBs mainly focusing on widening the electrochemical window of aqueous electrolytes as well as improving electrochemical properties of cathode, and anode materials.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.53-57
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• 2013

For the purpose of development of the extraction process of lithium ion from concentrated water eliminated from desalination process, an experimental research on the solvent extraction of lithium ion from aqueous solutions was performed. The effects of operating parameters, such as concentration of extractant, ratio of extracting solution/aqueous solution, pH of aqueous solution, were examined. The effect of sodium chloride, the major component of sea water, was also examined. Lithium ion in aqueous solutions of pH=10.2~10.6 adjusted by ammonia solution was most effectively extracted by extracting solution composed of 0.02 M TTA and 0.04 M TOPO in kerosine. The addition of sodium chloride in lithium aqueous solution significantly interfered the extraction of lithium ion.

• Korean Journal of Crystallography
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• v.11 no.4
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• pp.224-230
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• 2000

We have been investigated the flaking mechanism of the soda-line glass. The pH of aqueous solution approached to 10 and increased with reaction time by ion exchange reaction between Na/sup +/ ion of glass and H/sup +/ ion of aqueous solution under the conditions of below pH 9 of start solution. The relationship between the pH of solution and reaction time shows logarithm. Total dissolution reaction of glass components by OH/sup -/ ion in aqueous seems to be dominant after the pH solution reached to 10 and the dissolution rate linearly increased with reaction time. The above tow reactions are simultaneously occurred. The dissolved Ca/sup 2+/ ions are reprecipitated on the glass surface to Ca-compound. The flakes are formed by the separation of leached layer of glass due to the different thermal expansion coefficient.