• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.157-161
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• 2011

This study investigated decomposition the pathway and characteristics of fenitrothion, which is applied on the golf course for pesticide, by ZVI in batch reactor. The removal efficiencies of the pure fenitrothion and the commercial fenitrothion in Smithion by ZVI were compared. The fenitrothion was converted to 3-Methyl-4-nitrophenol and 4-Amino-m-cresol by ZVI. The fenitrothion decomposition rate by ZVI could be expressed by the first order reaction. As increasing the ZVI dosages, the first order rate constants and removal efficiencies increased. The surface area normalized rate constants for the pure fenitrothion and the commercial fenitrothion were 0.0398 and 0.1312 ($L/m^2{\cdot}hr$), respectively. The decomposition of the commercial fenitrothion in Smithion was faster than that of the pure fenitrothion by ZVI, the surfactant in Smithion lead to enhances solubility of fenitrothion and disperse ZVI.

• The Korean Journal of Community Living Science
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• v.24 no.2
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• pp.187-194
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• 2013

The purpose of this study was to define the optimal boxthorn berries washing method for developing the boxthorn berries cleaner. We analyzed the rate of removal of residual pesticides according to washing methods; 1st - habitual washing method, 2nd - drum rotation washing method, 3th - drum rotation and air bubble washing method, 4th - drum rotation and nozzle spray washing method, 5th - drum rotation and air bubble and nozzle spray washing method. A rate of removal of residual pesticides of 88% was detected in the drum rotation and air bubble and nozzle spray washing method, and a rate of 82% was detected in the habitual washing method. The drum rotation and air bubble and nozzle spray washing method appeared to be the best good washing effect compared to the habitual washing method(about 6% compared to 82.0% higher). Clothianidin Triadimefon, Triforine ingredients, the drum rotation and air bubble and nozzle spray washing method efficiency was lower compared to the habitual washing method removal efficiency.

• Carbon letters
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• v.8 no.4
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• pp.299-306
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• 2007

Four stream- activated carbons were prepared by carbonizing apricot stones at $600^{\circ}C$ followed by gasification with steam at $950^{\circ}C$ to burn-off's=17, 32, 49 and 65%. The textural parameters of these activated carbons were determined from nitrogen adsorption results at 77 K. The total pore volume and the mean pore radius increased with the increase of % burn-off whereas the surface area increased with the increase of burn- off from 17 to 32 and further to 49%. Further increase of burn-off to 65% was associated with a considerable decrease in surface area as a result of pronounced pore widening due to pore erosion. The surface pH values of the carbons investigated range between 7.1 and 8.2. The adsorption of oxamyl onto the activated carbon followed pseudo-second order kinetics and the equilibrium adsorption isotherms fitted Langmuir adsorption model. The adsorption of oxamyl proved to be of the physical type and took place in non-micropores. The amount of oxamyl adsorbed expressed as $q_m$ depends to a large extent to the surface area located in non-micropores $S^{\propto}\;_n$, where a straight line relationship passing through the origin was obtained.

• Carbon letters
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• v.8 no.2
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• pp.101-107
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• 2007

Activated carbons were prepared by impregnation of crushed clean date pits in concentrated solutions of phosphoric acid or zinc chloride followed by carbonization in absence of air at $600^{\circ}C$. Steam-activated carbon was prepared by gasifying $600^{\circ}C$-carbonization product at $950^{\circ}C$ to a burn-off = 50%. KOH- activated carbon was prepared by impregnating date pitscarbonization product obtained at $450^{\circ}C$ in concentrated KOH solution followed by carbonization at $840^{\circ}C$. Textural properties of these carbons were determined from nitrogen adsorption at $-196^{\circ}C$ and the chemistry of the carbon surface was investigated by determination and of the surface carbon-oxygen (C-O) groups using bases of variable strength and dilute HCl. The adsorption of endosulphan at $27^{\circ}C$ on all the carbons prepared was undertaken. Adsorption of this pesticide at 32 and $37^{\circ}C$ was also undertaken for steam-activated and KOH-activated carbons. Phosphoric acid-activated carbons and steamactivated carbons are mainly microporous and have high surface concentration of C-O groups of acidic nature. Steamactivated and KOH-activated carbons exhibited surface areas > 1000 $m^2/g$ and contain micro and non-micrpores. The adsorption of endosulphan was related to the surface area of non-micropores and was retarded by the high concentration of surface C-O groups. The thermodynamic properties indicated the feasibility of the adsorption process and the possible regeneration of the carbon for further use.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.2
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• pp.87-92
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• 2001

As well as arising the concern about pesticides known as a Carcinogenic or endocrine disorder substrates, magnitude was increased of reducing pesticides in soil or water. In this work, removals of residual pesticides on surface of solid phase were attempted by the photooxidation process with hydrogen peroxide. The optimum conditions for the removals of benomyl (carbamatic pesticide) chlorothalonil (Organochoric pesticide) were 350nm UV wavelegth and 20% (v/v) hydrogen peroxide solution as oxidant. Removals are negligible when UV radiation or the supply of hydrogen peroxide are solely applied on the target compoounds. Removal rates of the pesticides are accelerated by UV radiation with hydrogen addition. After 20 min of the treatment, about $2{\mu}g/cm^2$ of benomyl and $1,88{\mu}g/cm^2$ of chlorothalonil were disappeared on the surface of the solid phase.

• Microbiology and Biotechnology Letters
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• v.52 no.1
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• pp.44-54
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• 2024

One of the serious modern environmental problems is pollution caused by highly toxic pesticides. Only small amounts of applied pesticides reach their target, and the rest ends up in soil and water. Chlorpyrifos is a toxic, broad-spectrum organophosphate insecticide. In humans, chlorpyrifos inhibits acetylcholinesterase (AChE) in the peripheral and central nervous system, and particularly in children, small amounts of this pesticide cause neurotoxic damage. As the toxic effects of chlorpyrifos and its persistence in the environment require its removal from contaminated sites, it is essential to study the biological diversity of chlorpyrifos-degrading microorganisms. In this study, we sought to determine the chlorpyrifos-degrading ability of the bacterial strain Ochrobactrum intermedium PDB-3. This strain was isolated from soil contaminated with various pesticides and identified as PDB-3 based on morpho-cultural characteristics, MALDI-TOF MS, and 16S rRNA. Studies were conducted for 30 days in sterile soils containing initial concentrations of 50, 75, 100, and 125 mg/kg of chlorpyrifos. To determine the degradation of chlorpyrifos, a liquid culture of the strain was added to the soil at three optical densities: 0, and after 24 and 48 h (OD = 0.03, 0.2 and 0.32). Using GX-MS, we determined that chlorpyrifos was converted to 3,5,6-trichloro-2-pyridinol (TCP). We also found that with increasing optical density, rapid degradation of the initial concentration of chlorpyrifos occurred. Sterile soil without strain PDB-3 was used as a control sample.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.293-299
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• 2002

This experiment was conducted to elucidate the effects of fruit bagging on the amounts of pesticide residues on/in pears with two pesticides, chlorpyrifos 25% WP, and penconazole 5% WP, and two pear cultivars, Niitaka and Hwangeum-bae. Residues of chlorpyrifos and penconazole in bagged pears were only $0.4{\sim}27%$ of those in non-bagged one. Residues of both pesticides in bagged and non-bagged pears were steeply reduced in the field but slowly reduced during storage. Residues of chlorpyrifos were more in the peel than in the flesh, while penconazole in bagged pear was evenly distributed in the peel and flesh. Chlorpyrifos was evenly distributed in outer bag and inner bag irrespective of bag materials, while most of penconazole was found in outer bag rather than in inner bag. To produce safer pear from pesticide residues, removal of bag before storage is recommended.

• Food Engineering Progress
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• v.15 no.1
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• pp.28-33
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• 2011

UV-C and -B types of lamps, and $H_2O_2$ as a photocatalytic material were applied to optimize processing conditions for pesticides removal in Mandarine orange peel. Factors to affect the removal of pestrcides were arranged as a function of irradiation temperature, irradiation time, and $H_2O_2$ spray concentration. The optimum processing conditions for the chloropyrifos and the EPN removals in Mandarine orange peel were irradiation time of 60 min, irradiation temperature of $45^{\circ}C$ and $H_2O_2$ spray concentration of 1000 ppm. However, the optimum processing conditions for methidathion removal were 60 min of irradiation time, $40^{\circ}C$ of irradiation temperature and 1000 ppm of $H_2O_2$ spray concentration. The residual percentages of chloropyrifos, EPN and methidathion were 46, 49 and 28% after above irradiation processing, respectively.

• Analytical Science and Technology
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• v.19 no.2
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• pp.155-162
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• 2006

In this study, a series of experiments were conducted using a standard solution containing ${\alpha}$ and ${\beta}$-endosulfan to follow the removal effect of residual pesticides on soil and aqueous solution. An analytical method for residual pesticides was established by a gas chromatography equipped Ultra II[$(30m{\times}0.25mm(ID){\times}0.25{\mu}m$] capillary column and a ${\mu}$-electron capture detector(${\mu}$-ECD). Recovery rates of residual pesticides for soil samples were 96-100%. The amount of ${\alpha}$ and ${\beta}$-endosulfan that was spread in the soil was checked for various period of time. It indicated that the amount was reduced to 73 and 61%, respectively. When the water spread amount increased from 10 to 100 mL, ${\alpha}$-endosulfan was eliminated from 45 to 85% and while ${\beta}$-endosulfan from 44 to 88%. Removal rates of ${\alpha}$-endosulfan and ${\beta}$-endosulfan were 99% and 98% respectively within 30 minutes. It was assumed that the organic salts and strong alkali elements contained in the pesticide degradator hydrolyzed the residual pesticide.

• Journal of Food Hygiene and Safety
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• v.28 no.1
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• pp.31-35
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• 2013

In this study, the pesticide residues of polished rice and brown rice were measured after washing and cooking process. The initial concentrations of isoprothiolane and fthalide were $7.134{\pm}0.03mg/kg$ and $2.024{\pm}0.04mg/kg$ for polished rice, and $17.941{\pm}1.41mg/kg$ and $6.413{\pm}0.19mg/kg$ for brown rice, respectively. After first washing process, the removal rates of isoprothiolane were 23.0% (polished rice) and 18.5% (brown rice). Also, the case of fthalide, the removal rates were 14.0% and 9.7%, respectively. The removal dose was increased, but the removal rate was decreased in proportion to the number of washing process, After the cooking process, the removal rates of isoprothiolane and fthalide were 66.0% and 79.0% (polished rice), and 88.7% and 92.9% (brown rice), respectively. The removal rate of isoprothiolane was higher in the washing process, and the case of fthalide was higher in the cooking process. The optimum washing process for the pesticides removal was five times and the cooking process was the most effective to use the new water after soaking the rice in water during 30 minutes.