The CDI (Capacitive deionization) is one of the desalination technologies that use a carbon material electrode with large surface area and excellent electrical conductivity. Recently, research on a MCDI (Membrane Capacitive deionization) process, which is a combination of an ion-exchange membrane, has been actively conducted. In this study, we tried to find out the water quality of treated water and the concentration characteristics of concentrated water through TDS analysis by MCDI conventional and circulation process. In producing treated water, there was no significant difference in adsorption efficiency between MCDI conventional and circulation process. It was confirmed that both processes adsobed more than 96 %. However, the MCDI conventional process showed a low yield of 50 %, whereas the MCDI circulation process showed a high yield of 97.6 %. It's because, the wasted water was reused at desorption. In the case of the TDS concentration using MCDI circulation process, as the cycle progressed, the TDS concentration was concentrated up to 1,300 mg/L, but the rate gradually decreased. It is believed that this is because the volume of the concentrated water tank is limited, and the amount of soluble ions gradually decreases. As a result of analyzing the wasted water at MCDI circulation process through Ion Chromatography, it was confirmed that the concentration of all ions were concentrated. However, there was no significant difference in the types and proportions of analyzed ions. It is judged that the types and concentration of ions do not have a significant effect on adsorption and desorption in the MCDI circulation process.

Molten salt consisting primarily of eutectic LiCl-KCl is currently being used in electrorefiners in the Fuel Conditioning Facility at Idaho National Laboratory. Options are currently being evaluated for storing this salt outside of the argon atmosphere hot cell. The hygroscopic nature of eutectic LiCl-KCl makes is susceptible to deliquescence in air followed by extreme corrosion of metallic cannisters. In this study, the effect of occluding the salt into a zeolite on water sorption/desorption was tested. Two zeolites were investigated: Na-Y and zeolite 4A. Na-Y was ineffective at occluding a high percentage of the salt at either 10 or 20wt% loading. Zeolite-4A was effective at occluding the salt with high efficiency at both loading levels. Weight gain in salt occluded zeolite-4A (SOZ) from water sorption at 20% relative humidity and 40℃ was 17wt% for 10% SOZ and 10wt% for 20% SOZ. In both cases, neither deliquescence nor corrosion occurred over a period of 31 days. After hydration, most of the water could be driven off by heating the hydrated salt occluded zeolite to 530℃. However, some HCl forms during dehydration due to salt hydrolysis. Over a wide range of temperatures (320–700℃) and ramp rates (5, 10, and 20℃ min−1), HCl formation was no more than 0.6% of the Cl− in the original salt.

To develop flexible adsorbents for compact volatile organic compound (VOC) air purifiers, flexible as-spun zeolite fibers are prepared by an electrospinning method, and then zeolite particles are exposed as active sites for VOC (toluene) adsorption on the surface of the fibers by a thermal surface partial etching process. The breakthrough curves for the adsorption and temperature programmed desorption (TPD) curves of toluene over the flexible zeolite fibers is investigated as a function of the thermal etching temperature by gas chromatography (GC), and the adsorption/desorption characteristics improves with an increase in the thermal surface etching temperature. The effect of acidity on the flexible zeolite fibers for the removal of toluene is investigated as a function of the SiO2/Al2O3 ratios of zeolites. The acidity of the flexible zeolite fibers with different SiO2/Al2O3 ratios is measured by ammonia-temperature-programmed desorption (NH3-TPD), and the adsorption/desorption characteristics are investigated by GC. The results of the toluene adsorption/desorption experiments confirm that a higher SiO2/ Al2O3 ratio of the flexible zeolite fibers creates a better toluene adsorption/desorption performance.

The adsorption/desorption characteristics of toluene vapors filled with activated carbon(AC) were studied. Adsorption performance of AC was investigated according to flow rate, moisture content, and other factors. The breakthrough time was shortened as the flow rate and moisture content increased. The AC loaded with toluene was regenerated by programmed heating and pressure. AC was regenerated well, as the conditions of heating temperature(80oC) and pressure(100 torr) were appropriate. Toluene is more easily removed at low temperature than through thermal desorption methods. The test of AC regeneration was carried out three times.

We manufactured the metal hydrides of using a very easy and cheap way that Ti-12%Mg blending powder was mechanically milled with liquid milling media such as isopropyl alcohol (, containing oxygen) and hexane (, no oxygen) as hydrogen source. The synthesized in isopropyl alcohol contained the high oxygen of 11.2%, while one in hexane had the low oxygen content of 0.7%. Such a difference of oxygen content affected the dehydriding behavior, phase transformation, and microstructural evolution at high temperature, which was investigated through X-ray diffraction and DSC measurements, and electron microscope observations

Adsorption and desorption characteristics of methyl iodide at high temperature conditions up to 250℃ by TEDA-impregnated activated carbon, which is used for radioiodine retention in nuclear facility, was experimentally evaluated. In the range of temperature from 30℃ to 250℃, the adsorption capacity of base activated carbon decreased sharply with increasing temperature but that of TEDA-impregnated activated carbon showed higher value even at high temperature ranges. Especially, the desorption amount of methyl iodide on TEDA-impregnated carbon represented lower value than that on unimpregnated carbon. The breakthrough curves of methyl iodide in the fixed bed packed with base carbon and TEDA-impregnated activated carbon at high temperature were compared. TEDA-impregnated activated carbon would be applicable to adsorption process up to 150℃ for the removal of radioiodine in a nuclear facility.

A zeolitic material (Z-Y2) was synthesized from Coal Fly Ash (CFA) using a fusion/hydrothermal method under low-alkali condition (NaOH/CFA = 0.6). The adsorption performance of the prepared zeolite was evaluated by monitoring its removal efficiencies for Sr and Cs ions, which are well-known as significant radionuclides in liquid radioactive waste. The XRD (X-ray diffraction) patterns of the synthesized Z-Y2 indicated that a Na-A type zeolite was formed from raw coal fly ash. The SEM (scanning electron microscope) images also showed that a cubic crystal structure of size 1~3㎼ was formed on its surface. In the adsorption kinetic analysis, the adsorption of Sr and Cs ions on Z-Y2 fitted the pseudo-second-order kinetic model well, instead of the pseudo-first-order kinetic model. The second-order kinetic rate constant (k2) was determined to be 0.0614 g/mmol·min for Sr and 1.8172 g/mmol·min for Cs. The adsorption equilibria of Sr and Cs ions on Z-Y2 were fitted successfully by Langmuir model. The maximum adsorption capacity (qm) of Sr and Cs was calculated as 1.6846 mmol/g and 1.2055 mmol/g, respectively. The maximum desorption capacity (qdm) of the Na ions estimated via the Langmuir desorption model was 2.4196 mmol/g for Sr and 2.1870 mmol/g for Cs. The molar ratio of the desorption/adsorption capacity (qdm/qm) was determined to be 1.44 for Na/Sr and 1.81 for Na/Cs, indicating that the amounts of desorbed Na ions and adsorbed Sr and Cs ions did not yield an equimolar ratio when using Z-Y2.

Adsorption and desorption characteristics of the representative 10 kinds components consisting of gasoline vapor on activated carbon were investigated at the temperature range of -30℃∼25℃. The breakthrough curves of each vapors obtained by the Thomas model were well described the breakthrough experimental results of this study. The breakthrough times of each vapors were correlated with the molecular weight, density, and vapor pressure. The breakthrough times had greater correlation with boiling point than molecular weight and density. The slope of the breakthrough curve was a proportional relationship with the rate constant (k) of Thomas model expression. The higher the slope of the breakthrough curve, the rate constant was larger. The biggest slope vapor had the smallest adsorption capacity (qe). Adsorption and desorption characteristics of mixed vapor similar to the gasoline vapor were studied at room temperature (25℃). The mixed vapor consisting of 9 components; group A (pentane, hexene, hexane), group B (benzene, toluene), group C (octane, ethylbenzene, xylene, nonane) was examined. Group A was not nearly adsorbed because of substitution by group C, and the desorption capacity of group A was smaller than group C. The adsorbed substances were confirmed to be Group C.

This study analyzed concentration and characteristics of hazardous substances in treatment of leachate from carcass burial areas by using high temperature thermal desorption (HTTD). Concentrations of pollutants emitted from HTTD treatment of leachate contaminated soil of carcass burial sites satisfied the emission standards for 11 pollutants from domestic waste incineration facilities. Dioxin concentration was 0.0060 ng I-TEQ/Sm3 and 0.0061 (0.0055-0.0070) ng ITEQ/ Sm3 in the normal operation condition and the experimental condition, respectively, which are much lower than the MSWI Standard of 0.1ng I-TEQ/Sm3. As a result, it was considered that leachate from carcass burial areas could be treated by high temperature thermal desorption (HTTD).

The purpose of this work is to study the desorption characteristics of water vapor on zeolites saturated with water vapor. Three kinds of zeolite; zeolite 3A, zeolite 4A, and zeolite 5A were used as adsorbent. The desorption experiments with several different temperatures in the range of 90∼150℃ and several different flow rates in the ranges of 0∼0.4 L/min on zeolite bed were carried out. The desorption ability of water vapor was most effective on zeolite 5A among the compared zeolites. The higher the desorption temperature of water vapor was, the faster the desorption velocity was. The desorption ability of water vapor with an air supply was higher than that without an air supply. The most appropriate air flow rate was considered as 0.1 L/min.

The purpose of this work is to study the adsorption and desorption characteristics of acetone vapor and toluene vapor from adsorption tower in the VOCs recovery device. The six kinds of activated carbon with different pore structures were used and the adsorption and desorption characteristics were compared according to pore structure, desorption temperature, and adsorption method, respectively. Adsorption capacity of acetone vapor and toluene vapor by batch method was higher than that by dynamic method. Especially, activated carbon with medium-sized or large pores had more difference in adsorption capacity according to adsorption methods as a result of gradually condensation of vapors on relatively mesopore and large pores. Activated carbons with relatively large pores and relatively small saturated adsorption capacity had excellent desorption ability.

This paper describes the adsorption/desorpton efficiency of a modified activated carbon by irradiated microwave to treat toluene. By employing microwave energy, the regeneration time was considerably shortened compared with conventional thermal heating regeneration. New adsorbent called ACB(Activated Carbon-Bentonite) was prepared from powder activated carbon with mixing bentonite as a binder. Specific surface area, average pore size and total pore volume of ACB were calculated from the nitrogen adsorption/desorption isotherm. The surface of ACB was characterized with scanning electron microscope(SEM). The results showed that the specific surface area, total pore volume, average pore size of ABC was not influenced by regenerating cycle with microwave irradiation. Toluene was adsorbed onto ACB which desorbed by MW irradiation. Absorption capacity of ACB was 0.117 gtoluene/ gACB. Desorption efficiency of toluene increased as higher microwave output was applied.

This study was performed : 1) to establish the experimental analysis conditions for the sorption and desorption of toxic organic contaminants to/from the activated sludge, sediment, and clay, and 2) to determine the sorption and desorption equilibrium coefficients of some representative halogenated aliphatic compounds. Through the preliminary sorption test using Azo dye, a setting of quantitative experimental conditions to determine the sorption and desorption characteristics was decided as follows; equilibration time of 180 minutes, centrifuge for 15 minutes at 5000×g, and 500㎎/ℓ of TOC concentration. The sorption and desorption characteristics of halogenated aliphatic compounds onto activated sludge, sediment and clay could be described very well using the Freundlich isotherm. The preference of the average sorption capacity of the overall compounds showed in the sequence sediment 0.26㎎/g, clay 0.23㎎/g, and activated sludge 0.11㎎/g. The desorption rate of the sorbed compounds onto activated sludge, sediment and clay was approximately 89.8%, 35.3%, and 66.4%, respectively.

Laboratory experiments were conducted to examine the behavior of metalaxyl in environment, which was used as pesticide in green soil of golf course and as functions of the characteristics of adsorption, desorption and degradation in soil texture and organic matter contents. Acid water containing metalaxyl was conducted to evaluate the effects on adsorption, desorption and degradation. The adsorption of metalaxyl played more significant role in organic contents than clay contents, and pH increases more pH 2.5 than pH 5.6. The desorption of metalaxyl from contaminants soil decreased higher organic contents LS-soil than S-soil, but the desorption amount of metalaxyl increased more pH 5.6 than pH 2.5. The rate of degradation of metalaxyl in green soil environmental increased higher organic contents LS-soil than S-soil and decreased more pH 2.5 than pH 5.6. These results indicated that the behavior of metalaxyl of the green soil was affected the soil texture of the golf course. Increasing of organic contents, the adsorption amount of metalaxyl on soil increased. Moreover, the decrease of the pH of solution increased adsorption amounts and decreased desorption amounts. As the results, the transportation of metalaxyl in soil decreased the acidic rates. The acidification of soil by the acid rain increased the adsorption amount of metalaxyl, but the degradation of metalaxyl decreased. Therefore, it is possible to sustain contamination in run-off the stream and ground water by residuals in soil.

The biosorption and desorption of Cd were carried out using brown marine algae, known as the good biosorbent of heavy metals. The content of alginate bound to light metals could be changed by the physical and the chemical pretreatment of Sargassum fluitans biomass. The Cd uptake was independent of the alginate content. In case of protonated biomass, Cd uptake was the lowest because the alginic acid of biomass was dissolved to cadmium solution during the biosorption. The maximum Cd uptake of Sargassum biomass was ranged from 79㎎/g to 139㎎/g. In case of raw biomass, the higher the alginate content of biomass, the higher was the Cd uptake. 100% of Cd and light metals sorbed in the biomass were eluted at 0.1N HCl(pH 1.1). However, the elution efficiency in CaCl2 and Ca(NO3)2 solution was varied by the concentration, the solid to liquid ratio and the pH of calcium solution. The distribution coefficient between Cd and protons in the desorption solution at pH ranged from 1.6 to 2.9 was observed on the constant stoichometric coefficient(1.3).