• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.1
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• pp.85-90
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• 1998

The reaction rate of $CO_2$ with 2-amino-2-methyl-1-propanol (AMP), MEA monoethanolamine(MEA) and diethanolamine (DEA) in aqueous solutions has been determined using a stirred vessel with a plane gas-liquid interface over a wide range of concentrations of amines at different temperatures. The results show that the overall reaction rate is first order with respect to both $CO_2$ and amine. The reaction rate constant varies with temperature according to the relationship which agrees with the experimental data. The proposed interpretation is that the kinetic rate determining step is a reaction of $CO_2$ with amine to form carbamic acid which is then totally and immediately ionized.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.641-647
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• 2007

The phase transfer catalysis(PTC) reagent, ethyl tri-octyl ammonium bromide(ETABr), strongly catalyzes the reaction of p-nitrophenyi diphenyl phosphinate(p-NPDPIN) with benzimidazole(BI) and its anion($BI^{\theta}$). In ETABr solutions, the dephosphorylation reactions exhibit higher first order kinetics with respect to the nucleophile, BI, and ETABr, suggesting that reactions are occuring in small aggregates of the three species including the sub-strate(p-NPDPIN), whereas the reaction of p-NPDPIN with $OH^{\theta}$ is not catalyzed by ETABr. This behavior for the drastic rate-enhancement of the dephosphorylation is referred as 'aggregation complex model' for reaction of hydrophobic organic phosphinates with benzimidazole(BI) in hydrophobic quarternary ammonium salt(ETABr) solutions.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.4
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• pp.241-247
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• 2000

This paper reports on an experimental study of the absorption of COS in a secondary amine diethanolamine. The primary objectives were to investigate an analogy between $N_2$O and COS, thereby allowing an estimation of the physical solubility and diffusivity of the sulfur gases in the reacting amine solutions. The solubilities and diffusivities of $N_2$O and COS in 5~25% aqueous polyethylene glycol at $25^{\circ}C$ were measured. The results appeared to verify the use of an $N_2$O-COS analogy for estimating the solubility and diffusivity of COS in aqueous solutions of alkanolamines up to an approximate 25 weight % concentration. The mean deviation of the $N_2$O analogy relative to the measured solubilities was 3.7%, and the mean deviation between the analogy and the measured diffusion coefficients using the experimental values for Hcos/PEG was 14.6%.

• Journal of Environmental Science International
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• v.9 no.6
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• pp.517-522
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• 2000

Separation of strontium ion from synthetic seawater in the contained liquid membrane permeator with two micro-porous films was performed. The permeator consisted of a liquid membrane and two cells for aqueous solutions. The liquid membrane consisted of $D_2EHPA(di-2-ethylhexy1-phosphoric acid)$ and DCH18C6 (dicyclohexano-18-crown-6),diluted to 30 vol% with kerosine and was trapped between two micro-porous hydrophilic films. This liquid membrane separated two aqueous solutions, one of which was synthetic seawater and the other of which was the stripping solutions consisting of 1mol/L $H_2SO_4$ solution. The effects of various operating parameters on the extraction rate and equilibrium extraction ratio of strontium ion from synthetic seawater were experimentally examined. The addition of DCH18C6 to the $D_2EHPA$ solution caused synergy effect on the extraction of strontium ion. The permeator extracted strontium ion from synthetic seawater effectively with high membrane life time.

• 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 environmental and Sanitary engineering
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• v.13 no.1
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• pp.174-184
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• 1998

Biosorption characteristics were investigated to discuss the use of agar entrapped Spirulina to remove of heavy metal ions from polluted waters. Agar immobilized algae were used as bioadsorbent in continuous reactor for heavy metal ions removal. The process solution contains Pb, Cu, and Cd as single ion and binary ions. In the adsorption of single heavy metal ions by agar immobilized Spirulina, the adsorption reached within 1hr and observed diffusion limitation differed from the free algal cell adsorption. The optimum pH for the adsorption of heavy metals was 4.5 but the influence of pH decreased less than that of free algal cell. Also, the adsorption characteristics of single heavy metal ions with agar immobilized Spirulina fitted the BET isotherm. Both of experiments of free algal cell and agar immobilized algae showed higher removal efficiency in the single ion solutions than binary ions solutions. The experimental results in the packed column with agar immobilized algae were over 90% of removal efficiency for the Pb, Cu, and Cd in single ion solutions.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.29-34
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• 2011

This study examined the effect of environmental variables, such as the NaOH concentration and solution temperature, on the rate of hydrogen generation from NaOH solutions through the corrosion of used aluminum cans as a potential candidate material for the safe and economic production of hydrogen. Corrosion of the used aluminum cans was promoted by increasing the NaOH concentration and solution temperature because of the loss of aluminum passivity. The measured rate of hydrogen generation from the NaOH solutions increased with increasing NaOH concentration due to the catalytic activity of NaOH in the hydrolysis process. However, at higher solution temperatures, the rate of hydrogen generation rate was less affected by the NaOH concentration than that at lower temperature.

• Journal of Environmental Science International
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• v.31 no.10
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• pp.891-899
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• 2022

This study investigated whether an educational program could alter students' perceptions of the causes of and solutions to climate change. On October 23, 2020, a 3-hour climate change educational program was provided to 400 high school students in Suncheon City, (Jeonnam Province, South Korea). According to the program, climate change represents a social dilemma, or tragedy of the commons; it also asserts that collective action aimed at strengthening government policy is the optimal solution to climate change, and concludes that motivated citizens should convey their opinions directly to the government through political action. After the program, the students made and shared placards calling for policy-based responses to climate change. Questionnaires completed by the students before and after the program revealed that their perceptions of the causes of and solutions to climate change changed significantly. This case study indicates that education programs have the potential to alter students' perspectives and promote actions aimed at mitigating and adapting to climate change.

• Environmental Engineering Research
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• v.8 no.2
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• pp.98-106
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• 2003

• Journal of Environmental Science International
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• v.20 no.1
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• pp.119-126
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• 2011

In this study, reaction model and reactions rate accelerated by o-iodosobenzoate ion(IB$^{\ominus}$) on hydrolysis reaction of p-nitrophenyl valate(NPV) using ethyl tri-octyl ammonium mesylate(ETAMs) for quaternary ammonium salts, the phase transfer catalysis(PTC) reagent, were investigated. The effect of IB$^{\ominus}$ on hydrolysis reaction rate constant of NPV was weak without ETAMs solutions. Otherwise, in ETAMs solutions, the hydrolysis reactions exhibit higher first order kinetics with respect to the nucleophile, IB$^{\ominus}$, and ETAMs, suggesting that reactions are occurring in small aggregates of the three species including the substrate(NPV), whereas the reaction of NPV with OH$^{\ominus}$ is not catalyzed by ETAMs. Different concentrations of NPV were tested to measure the change of rate constants to investigate the effect of NPV as substrate and the results showed that the effect was weak. This means the reaction would be the first order kinetics with respect to the nucleophile. This behavior for the drastic rate-enhancement of the hydrolysis is referred as 'Aggregation complex model' for reaction of hydrophobic organic ester with o-iodosobenzoate ion(IB$^{\ominus}$) in hydrophobic quarternary ammonium salt(ETAMs) solutions.