• Bulletin of the Korean Chemical Society
• /
• v.31 no.2
• /
• pp.335-338
• /
• 2010

In this study, the atmospheric plasma treatment with $He/O_2$ was conducted to modify the surface chemistry of carbon fibers. The effects of plasma treatment parameters on the surface energetics of carbon fibers were experimentally investigated with respect to gas flow ratio, power intensity, and treatment time. Surface characteristics of the carbon fibers were determined by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Fourier transform infrared (FT-IR), Zeta-potential, and contact angle measurements. The results indicated that oxygen plasma treatment led to a large amount of reactive functional groups onto the fiber surface, and these groups can form together as physical intermolecular bonding to improve the surface wettability with a hydrophilic polymer matrix.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.13 no.3
• /
• pp.228-233
• /
• 1993

Method for the sun curing dehydration of pig excreta by using vinyl house was described. We determined effects of the dehydrated pig excreta on the yields of whole crop corn and proximate chemical composition of whole crop corn. Pig excreta were dehydrated upto 15% of moisture content by the 3-4 days of sun curing dehydration in vinyl house in the summer period. There was no significant difference between the dehydrated pig excreta treatment and the chemical fertilizer treatment on dry matter(DM) content, DM yield and crude protein contents of whole crop corn. Ca and Mg contents by the dehydrated pig excreta treatment were lower than those by thechemical fertilizer treatment. In the contrast, K content by the dehydrated pig excreta treatment was higher than those by the chemical fertilizer treatment. and dehydrated pig excreta treatments were higher in K/Ca+Mg ratio than chemical fertilizer treatment. These results suggested the availability of the sun curing dehydration of pig excreta in vinyl house in small-scale animal industry. In addition, the dehydrated pig excreta treatment showen similar effects to the chemical fertilizer treatment on dry matter yields and contents of chemical composition of whole crop corn. These results suggest that using the sun curing dehydration of pig excreta could reduce the chemical fertilizer cost. However, we need more study to the relationship between the unbalanced mineral contents and animal health.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.5
• /
• pp.573-576
• /
• 2006

The efficacy of integrated ozone oxidation-biodegradation treatment was examined in the treatment of petrochemical wastewater with a special focus on the overall treatment time. When raw wastewater with chemical oxygen demand(COD) of 70-80 mg/L was oxidized by ozone, approximately 20% of initial COD was removed in less than 1.5 min at a dosing rate of 400 mg $O_3/L{\cdot}h $. No further decrease in COD was observed for the extended ozone treatment up to 30 min. Biological treatment alone showed a rapid reduction of COD to 40-50 mg/L, subsequently resulting in the decreased rate of COD removal. Pre-treatment by ozone before biological treatment did not significantly affect the specific rate of COD removal in a biological treatment. When ozone oxidation followed biological treatment, the extent of COD removal by ozone oxidation was greater compared to that of biologically-treated wastewater for a shorter time. Taken together, it was decided that the biological treatment time could be reduced if the treatment processes of concern will be properly arranged.

• Environmental Engineering Research
• /
• v.22 no.1
• /
• pp.1-11
• /
• 2017

One of the most threatening consequences of eutrophic freshwater reservoirs is algal blooming which typically occur after the long a mega drought or/and irregular rainfall under influence of climate change. The long-term experiences of chemical treatment are known as a most practical effort to reduce health concerns from human exposure of harmful cyanobacteria as well as to preserve ultimate freshwater resources. Even though these conventional chemical treatment methods do not completely solve the algal residue problem in water treatment plant or directly in the water bodies, they still have big advantages as fast and efficient removal process of cyanobacteria due to cheaper, easier to manage. This review summarizes their chemical treatment scenarios of the representative coagulants, pre-oxidants and algaecides composed to chemical compounds which immediately may help to manage severe cyanobacteria blooms in the summer seasons.

• Journal of Environmental Science International
• /
• v.14 no.7
• /
• pp.683-689
• /
• 2005

The consecutive combination process of a biological process as the pre-treatment and a chemical process as the post-treatment is applied for the dyeing wastewater. The poor efficiency of biological treatment using pure oxygen makes the chemical treatment cost high. It is necessary to improve the efficiency of biological treatment in order to reduce the cost of chemical treatment. The purpose of this paper is to find the minimum dose of chemical reagent to fit the Discharged Water Quality Standards for the different biological treatment effluents. Results revealed that the minimum dosage of Fenton's reagent lead to save the cost of chemical treatment based on the guideline dose in the treatment plant. The possible maximum saving reagents was up to $70\%$ for the effluent of the pilot plant packed with the carrier imbedded microorganisms which were selected from the present treatment plant.

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.1
• /
• pp.115-121
• /
• 2006

The purpose of this study was to investigate applicability of pretreatment on the existing biological treatment for domestic wastewater reclamation. From Jar Tests, it was found that optimum dosage of coagulant was PAC 0.5mg/L and $FeCl_3$ 180mg/L for urban sewage. In this study, PAC 0.5mg/L was selected considering sludge production and the amount of coagulant required. In a continuous experiment performed with combining chemical coagulation and biological treatment, a considerable removal efficency was obtained in term of BOD, SS, T-N, T-P and ABS. When the raw sewage was supplied into the pre-chamical treatment facility, the removal of BOD and SS was 48.3% and 81.1%. However T-N removal was very low which means T-N consists of $NH_3-N$ mostly. T-P was almost completely recluced by the chemical addition. The effluent BOD & SS was 57~76 and 21~43mg/L, which could reduce the size of biological treatment facility. From the cost estimation pre-chemical treatment could save around half of the area required for biological treatment with post ceagulation.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2006.06a
• /
• pp.265-266
• /
• 2006

The chemical conversion coating formed on magnesium alloy investigated for low cost and harmless in environment by using the colloidal silica as the main component. The film formed in 298 K is thick, the film, which was thought combination of Si-O, was formed. The film formed in 313 K is thinner than that in 298 K. The quantity of film formed at high temperature such as 333 K and 353 K is smaller than dissolved quantity. At the anodic polarization experiment, corrosion resistance in sealing by hot water after chemical conversion treatment in basic solution condition get worse than that in comparison with basic solution condition. In salt spray test, the ratio of black rust on specimen that did not conducted chemical conversion treatment was five times or more compared with those of chemical conversion treated specimen. The film thickness of chemical conversion coating produced by alkali treatment process is thinner than in comparison with that of specimen produced in basic chemical conversion treatment solution condition. It is thought, however, that it showed good corrosion resistance during salt spray test because the area of microcracks is small.

• Journal of environmental and Sanitary engineering
• /
• v.19 no.3 s.53
• /
• pp.58-64
• /
• 2004

Biological treatment of wastewater was studied with a purpose to remove TOC by the reduction of water hardness. The optimal conditions of coagulant were determined by reaction time and amount of coagulant. Experimental results indicate that the biological treatment after physico-chemical treatment was found to provide very efficient removal efficiency in the process to treat the textile wastewater, including the carbon dioxide treatment. The combined process of carbonization in the physico-chemical treatment respectively was increased the removal efficiencies of $30.0\%$ in biological treatment in comparison with exclusive biological treatment. As a result, the treatment of hardness after carbonization had the best removal efficiency of approximately $60.0\%$. The removal efficiencies in the exclusive biological treatment using Bacillus subtilis and after carbonization were increased by $38.9\%\;and\;69.0\%$ respectively. The combined Bacillus subtilis-assisted biological treatment was determined to be the most effective method to treat the textile wastewater in an economic point of view, the water quality in the wastewater treatment plays an important role.

• Journal of the Korean Wood Science and Technology
• /
• v.25 no.1
• /
• pp.65-70
• /
• 1997

The effects on the enzymatic hydrolysis of waste paper treated with physical or chemical treatment were investigated. To gain the higher saccharification rate, physical or chemical treatment are necessary in enzymatic conversion process of waste paper. The major deterrents to the effective utilization of waste paper for enzymatic conversion process are phenolic compounds, cellulose crystallinity and coating materials. In the enzymatic hydrolysis of waste paper, the deterrents through enzymatic conversion process can be eliminated by the physical or chemical treatment. This study was performed to obtain the optimal condition for enzymatic conversion process of non-treated waste paper and to review effects on enzymatic conversion process of waste paper treated with physical or chemical methods. In the aspect of saccharification rate, waste paper treated with 1.5% sodium hypochlorite was the most effective and in physical treatment methods, multi-stage treatment(autohydrolysis+refining treatment) was more effective than the other physical treatment.

• Transactions of the Korean hydrogen and new energy society
• /
• v.6 no.2
• /
• pp.91-100
• /
• 1995

To investigate the surface state of $Mg_2Ni$ which was exposed to the air, a chemical treatment was undertaken with $H_2SO_4$ solution. During chemical treatment, the change of pH was measured continuously and the chemically treated specimen was hydrided to study the effect of chemical treatment on the hydrogenation. The pH changing behavior with the various $H_2SO_4$ concentration appeared very diffemrently. Especially in the solution including 3CC $H_2SO_4$, the behavior of pH change can be divided 3 steps. It is also shown that the $Mg_2Ni$ chemically treated with $H_2SO_4$ can be hydrided even under room temperature. By the SEM observation the was reasion that after chemical treatment the surface of a particle was covered with Ni layer.