• Transactions of the Korean hydrogen and new energy society
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• v.2 no.1
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• pp.1-6
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• 1990

The desorption kinetics of $Mg_2Cu$ hydride were studied by thermal analysis technique in order to study desorption behavior and to relate thermal desorpton spectra to occuption site of hydrogen. It is suggested that a continuous ${\alpha}/{\beta}$ interface boundary is formed at the initial absorption stage. And the desorption kinetics were analysed by the theoretical equation which was derived on the basis of continous moving boundary model. The number of thermal desorption peak corresponds to the occupation sites of hydrogen. The apparent activation energy for the desorption of $Mg_2Cu$ hydride is 91 KJ/mol.

• KIEAE Journal
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• v.9 no.2
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• pp.53-58
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• 2009

There are increasing developments and uses of functional building materials are recently developed and introduced to the test method for the materials. Especially, moisture problem has a major role are also being established in indoor air quality problems. The purpose of this study is to evaluate the water vapour adsorption/desorption property of a ceiling material. The variation of the temperature and moisture were measured with the application materials by mock up test based on JIS 1470-1. The result shows that water vapour adsorption/desorption property of ceiling material is appeared in changes of moisture adsorption and desorption in comparison with that of a general ceiling material. Therefore, in case of decreasing and increasing in humidity, these materials can be used as an finishing material to sustain comfort condition.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.94-103
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• 2014

In this study washing efficiency and desorption isotherms for heavy petroleum oil (HPO), Zn, and Pb bound to complex contaminated soils were examined using various soil flushing agents. Sodium dodecyl sulfate (SDS), methanol, ethylene diamine tetraacetic acid (EDTA), and citric acid were selected as soil flushing agents. 3% (w/v) and 4% SDS showed the highest removal efficiency for HPO, but the difference was not statistically significant (p > 0.05). Thus, 3% SDS was chosen as the best soil flushing agent for HPO. In the case of heavy metals, 0.1-M EDTA showed the highest removal efficiencies. But 0.05-M citric acid was selected due to its economic and eco-friendly strengths. The desorption isotherms obtained using Freundlich and Langmuir models indicated that the maximum desorption characteristics ($K_F$ and $Q_{max}$) of HPO with 4% SDS and 90% methanol and heavy metals with 0.1-M EDTA and 0.1-M citric acid, respectively, were markedly lower than in other cases. In addition, when 4% SDS and 90% methanol were used for HPO in the range of $C_e$ higher than 600 mg/L, and when 0.1M citric acid and 0.1M EDTA were used for Zn and Pb in the range of $C_e$ higher than 300 and 100 mg/L, respectively, the distribution constant converged to certain levels. Thus, constant values of $K_U$ and $K_L$ were determined. It was found that these constants represent the maximum desorption capacity and they can be used as distribution coefficients of desorption equilibrium for the flushing agents. The results of this study provided fundamental information for the selection of the best agents as well as for the process design and operation of soil washing/soil flushing of complex contaminated soils.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.4
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• pp.293-300
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• 2021

Recently, various researches have been studied, such as water treatment, water reuse, and seawater desalination using CDI (Capacitive deionization) technology. Also, applications like MCDI (Membrane capacitive deionization), FCDI (Flow-capacitive deionization), and hybrid CDI have been actively studied. This study tried to investigate various factors by an experiment on the TDS (Total dissolved solids) removal characteristics using MCDI module in aqueous solution. As a result of the TDS concentration of feed water from 500 to 2,000 mg/L, the MCDI cell broke through faster when the higher TDS concentration. In the case of TDS concentration according to the various flow rate, 100 mL/min was stable. In addition, there was no significant difference in the desorption efficiency according to the TDS concentration and method of backwash water used for desorption. As a result of using concentrated water for desorption, stable adsorption efficiency was shown. In the case of the MCDI module, the ions of the bulk solution which is escaped from the MCDI cell to the spacer during the desorption process are more important than the concentration of ions during desorption. Therefore, the MCDI process can get a larger amount of treated water than the CDI process. Also, prepare a plan that can be operated insensitive to the TDS concentration of backwash water for desorption.

• Environmental Engineering Research
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• v.15 no.4
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• pp.225-230
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• 2010

In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of $600^{\circ}C$ were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of $300^{\circ}C$ would be the most economic conditions.

• Journal of Environmental Science International
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• v.21 no.10
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• pp.1195-1202
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• 2012

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.

• Bulletin of the Korean Chemical Society
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• v.20 no.9
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• pp.1061-1066
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• 1999

The adsorption of CO on W(111) surface in the range of adsorption temperature between 300 K and 1000 K has been studied using AES, LEED, and TDS in an UHV system. After CO saturation at 300 K, four desorption peaks are observed at temperatures (K) of about 400, 850, 1000, and 1100 in thermal desorption spectra, called as α, β1, β2, and β3 state, respectively. The state was attributed to molecular species of CO, which is well known. Because the CO in βstates (especially the β3 state) is still debated as to whether it is dissociative or non-dissociative, the β3 state is mainly discussed. By using the variation method of heating rate in the thermal desorption spectrometry, the desorption energy and pre-exponential factor for the β3 state are evaluated to be 280 kJ/mol and 1.5×10 12 s-1 , respectively. A lateral interaction energy of 5.7 kJ/mol can also be estimated by Bragg-Williams approximation. To interpret the thermal desorption spectra for the β3 state, moreover, those for the model of a first order and a second order desorption are simulated using quasi-chemical approximation. In this study, a model of lying-down CO species is proposed for the β3 state of CO adsorption.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.547-556
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• 2000

A study have been conducted for the adsorption and desorption characteristics of Cu ion using manganese nodule as adsorbent. For 100 ppm Cu ion solution, the adsorbed amount of Cu ion was more than 90 % at equilibrium state. Adsorption was equilibrated in 42 hours the adsorption reaction was shown to be first order reaction. For the desorption reaction of Cu ion in the region of solution pH 3.5~9.5, the desorption was completed in the acidic region, but it has been decreased as the pH was raised. Also, the desorption rate was higher in the acidic region compared with alkaline region. The desorbed amount was decreased as the reaction temperature increased, therefore, the desorption reaction was thought to be exothermic. Also, several thermodynamic properties were calculated based on experimental results and compared with theoretically driven values. To see the effect of complexing agent on the desorption of Cu ion, EDTA was introduced and the des orbed amount increased in the presence of EDTA.

• Journal of Environmental Science International
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• v.18 no.5
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• pp.501-508
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• 2009

In this study, the characteristics of granular activated carbon (GAC) supported metal was investigated in an area influenced by flame discharge and temperature variation during irradiating microwave. The modified GAC was formulated by impregnating metal hydroxides of nickel (Ni/GAC), barium (Ba/GAC), copper (Cu/GAC), zinc (Zn/GAC), cobalt (Co/GAC) and lanthanum (La/GAC). Ba/GAC was selected as it showed lack of spark discharge and temperature increasing aspects. Comparison of adsorption and desorption amount of GAC and Ba/GAC showed that adsorption and desorption rate of the GAC were higher than those of Ba/GAC. The results show that the presence of barium can decrease adsorption/desorption rate because of plugging pore of GAC. Toluene regeneration rate of Ba/GAC was better than that of GAC due to barium loading. Finally, GAC with barium can be controled a rapid increasing temperature and spark discharge, increased the regeneration rate of toluene during desorption by irradiating microwave.

• Applied Chemistry for Engineering
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• v.1 no.1
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• pp.30-34
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• 1990

This paper summarizes fundamental research on a metal hydrides for the development of new energy. We made a study of the characteristics of the hydrogen absorption-desorption of $DiNi_5$ alloys. As a result, we found that the maximum amount of the hydrogen absorption of $DiNi_5$ alloys (the maximum in the absorption equilibrium pressure section) was H/M=1.04 at $30^{\circ}C$. The hysteresis was the smallest at $30^{\circ}C$. The capability of the hydrogen absorption-desorption was excellent. The number of cycles of the hydrogen absorption-desorption was about 9000 times at $30^{\circ}C$. We found also that the rate of the hydrogen desorption was the largest at $40^{\circ}C$.