• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.11a
• /
• pp.119-123
• /
• 2000

In-situ treatment technologies have been proposed to transform or remove pollutants from contaminated groundwater. Zero-valent iron(Fe$^{0}$ ), metallic iron, is being evaluated as a permeable reactive material to retard the transport of wide array of highly mobile contaminants in groundwater. In this research, tetrachloroethylene(PCE) dechlorination by powdered zero-valent iron in buffered aqueous solution was studied with and without the presence of surfactants. The rate of dechlorination of PCE by zero-valent iron with surfactant was much higher than without surfactant. The presence of surfactant increased the apparent rate of dechlorination because the surfactants influenced the dissolution of PCE into the aqueous phase.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.04a
• /
• pp.405-408
• /
• 2003

The soild phase microextraction(SPME)fiber which contains 100${\mu}{\textrm}{m}$ polydimethyl siloxane of a stationary phase was used for the analysis of volatile organic compounds contained in aqueous solution. volatile organic compounds, which were spiked in blank water and extracted by the headspace SPME techique, were analyzed by gas chromatography/flame ionization detector(GC/FID). The optimu condition of SPME fiber is determined that the analytes were extracted for 40min from extracts by using PDAfS100${\mu}{\textrm}{m}$ fiber. This new method could have wide application for the analysis of VOCs in aqueous solution.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.04a
• /
• pp.302-305
• /
• 2003

The purpose of this study was to assess the effect of surfactant on the rate of NAPLs(non-aqueous phase liquids) solubilization. The experimental variables were surfactant type, NAPLs type and water type. The main experimental designs were consists of two phases. The solubilization rate is sensitive to surfactant type based on this test. Used aqueous surfactants were solubilized and removed 72.77 to 89.90% of toluene, PCE(tetrachloroethylene) from the contaminated water during the test, respectively. T60 has higher and stable recovery ratio than SDS in surfactant type but, the micelle of the T60 is more weaker than that of SDS based on this study's results. And the solubilization rate in used water type was almost same.(deionized water, surface water).

• Bulletin of the Korean Chemical Society
• /
• v.17 no.9
• /
• pp.854-857
• /
• 1996

Absorption and luminescence spectra of Eu3+ (aquo) and the two different 1: 3 Eu3+: ligand systems in aqueous solutions are measured under mild acidic pH condition. The oxydiacetate (ODA) and dipicolinate (DPA) ligands, forming the similar geometric complexes, are used in this work. The three intensity parameters, Ωλ (λ=2, 4, and 6) are empirically determined by applying the Judd-Ofelt theorem to the oscillator strengths of the six absorption bands arising from the ground 7F0 state. Among the three intensity parameters, the Ω2 is found to response markedly to a miner change in the ligand environment via the 7F0→5D0 transition. In addition, the relative oscillator strengths of the four luminescence bands in the visible region, assigned to the 5D0→7FJ (J=1, 2, 3 and 4) transitions are obtained to investigate their sensitivity to the ligand environment. Among the four bands, the 610 nm band, attributed to the 5D0→7F2 transition, shows hypersensitivity in the luminescence.

• Environmental Engineering Research
• /
• v.24 no.1
• /
• pp.99-106
• /
• 2019

Using the abandoned agricultural by-product corncobs, the most commonly used methylene blue (MB) dyestuffs were removed. This experiment is very meaningful because it is the recycling of resources and the use of environmentally friendly adsorbents. According to the Hauser ratio and porosity analysis, the corncob has a good flow ability of the adsorbent material and many pores, which is very advantageous for MB adsorption. As a result of the experiment, MB concentration of less than 0.005 g/L was very efficiently removed with 10 g/L of bioadsorbent corncob and the maximum adsorption capacity of corncob for MB dyes was obtained at 417.1 mg/g. In addition, adsorption process of MB onto corncob was a physical process according to adsorption energy analysis. Corncob can efficiently and environmentally remove MB in aqueous solution, and is very cost effective and can recycle the abandoned resources.

• Journal of Korean Society on Water Environment
• /
• v.27 no.2
• /
• pp.141-146
• /
• 2011

Loess, a natural clay, was evaluated as an adsorbent for the decolorization of Acid Orange II, an azo and reactive dye, from aqueous solution. Adsorption studies were performed at $30^{\circ}C$ and the effect of reaction time, loess dosage, initial concentration, loess particle size, pH, agitation rate were investigated to determine the optimum operation conditions. The removal efficiencies of color were measured to evaluate the effectiveness of loess. From this study, it was found that optimal reaction time was 10 min. Color removal efficiencies of Acid Orange II were increased as higher loess dosage, initial concentration and agitation rate. However, color removal efficiencies decreased when pH is high and loess particle becomes large. Adsorption of Acid Orange II fitted to the pseudo-second-order rate kinetics more than first-order rate kinetics. Langmuir and Freundlich adsorption isotherm constants and correlation coefficients were calculated and compared. It was concluded that the adsorption data of Acid Orange II onto loess fitted to the Freundlich model more than Langmuir model.

• Journal of Environmental Science International
• /
• v.14 no.12
• /
• pp.1177-1183
• /
• 2005

The kinetics of the reaction of methyl mercaptan into aqueous diethanolamine were studied over a range in temperature ($20^\~60{\circ}C$) and amine concentrations (0-40 $wt\%$) using a wetted-sphere absorber. The physicochemical properties needed to interpret the data are the solubility and diffusivity of methyl mercaptan in the aqueous diethanolamine solution. The density and the viscosity were obtained and correlated in the experimental range. The Wilke Chang equation was applied to estimate the diffusion coefficient. The enhancement factor was found to be high temperature is below than low temperature. It means the absorption rate with chemical reaction is lower than the physical absorption rate.

• Journal of Korean Society on Water Environment
• /
• v.20 no.3
• /
• pp.251-255
• /
• 2004

Laboratory experiments were performed to investigate oxidation system using ozone and hydrogen peroxide for treating water contaminated with phenol. We were able to greatly improve the oxidation efficiency of the aqueous phenol using hydrogen peroxide and ozone. Two methods were compared and analyzed in this study. In the consequence through the methods, we concluded that the $O_3/UV$ is superior to the hydrogen the results. The decomposition efficiency of aqueous phenol by $H_2O_2$. was exceeded at 83.3% in the concentration of phenol, 5, 15, 25 ppm, respectively. The rate of decomposition reaction by $H_2O_2$. was very slow. In the occasion of the fractional life, it was determined the value that $1.61{\times}10^{-5}(l/mol)^{1.172}sec^{-1}$, $3.75{\times}10^{-5}(l/mol)^{0.792}sec^{-1}$, $4.11{\times}10^{-5}(l/mol)^{1.782}sec^{-1}$. The rate of decomposition reaction of aqueous phenol by $O_3$ was fast compared to the $H_2O_2$. We concluded that the $O_3$ method is useful with the consideration of the reaction time 30 minutes. In the occasion of the fractional life, it was determined the value that $1.094{\times}10^{-4}(l/mol)^{0.933}sec^{-1}$, $2.1{\times}10^{-4}(l/mol)^{0.842}sec^{-1}$, $7.22{\times}10^{-4}(l/mol)^{1.332}sec^{-1}$.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 1998.05a
• /
• pp.1-2
• /
• 1998

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.20 no.2
• /
• pp.133-136
• /
• 1984

The characteristics of the stress corrosion cracking of SUS 304 stainless steel were studied with the specimens of the constant displacement type under the environment of various MgCl sub(2) aqueous solutions. Main results obtained are as follows; 1) Latent time of crack initiations is delayed in the SCC under low condition of initial stress intensity K sub(Ii) value. 2) SCC occurs owing to the passive film-rupture by both load and Cl ion under MgCl sub(2) boiled aqueous solution. 3) The susceptibility of SCC can be largely improved by reducing the temperature in case of the high concentration of MgCl sub(2) aqueous solution.