The Photodegradation Of Chlorpyrifos

Photodegradation of chlorpyrifos was studied in different kind of waters (soil suspension water, distilled water, pond water, river water and ground water) under the illumination of three light sources (UV- 254, UV- 365 and Simulations sunlight (VIS) were investigated. The rate of degradation of chlorpyrifos was as follow: distilled water > ground water > river water > pond water > soil suspension water, the degradation rate showed to faster under UV- 254 than in UV-365 and VIS. The effect of light intensity on the degradation of chlorpyrifos in distilled water under UV- 254, UV- 365 and VIS were also investigated, the degradation rate was showed to be increased by increasing the light intensity, pH value and the concentration of chlorpyrifos also effects the degradation of chlorpyrifos in water. In soil, the photodegradation of chlorpyrifos on six different texture of soils and under UV- 254, UV- 365 and VIS sources, the degradation rate was directly related to the organic matter content of the soil, light intensity, concentration of chlorpyrifos and the moisture level were showed to effect the degradation rate of chlorpyrifos on soil surface. The degradation rate of chlorpyrifos on leaf surface, in leaf extract and in diluted leaf extract were investigated under various lights (UV- 254, UV- 365, Simulations sunlight and natural sunlight) the results showed that faster degradation rate were observed on leaf surface than in leaf extract. The effect of humic substances showed that, the degradation rate of chlorpyrifos was decreased when adding humic acid (HA) and increased when adding fulvic acid, (FA) the companied effect of both HA and FA showed to accelerate the degradation of chlorpyrifos but is was slower when comparing to the effect when adding FA alone. The photodegradation of chlorpyrifos in soil was investigated when adding some other pesticides and exposed to UV-254. Seven organophosphorus pesticide (omethoate, methamedofos, trichlorfon, dimethoate, malathion, phosmet and fenthion) showed to have photoquench efficiency against the photodegradation rat of chlorpyrifos, while pyrethroid insecticide (fenvalerate, esfenvalerate, cyhalothine, cypermethrin, deltamethrine, tetramethrin) showed to accelerate the degradation rate of chlorpyrifos except for fenvalerate, which showed to have photoquench efficiency. Photocatalysis study of chlorpyrifos was conducted to investigate The photodegradation rate of chlorpyrifos in water when adding some photosensitizers results showed that the presence of PbO, T1O2. ZnO, Acetone and H2O2 will accelerate the degradation of chlorpyrifos when exposed to UV-254 light source. At the high concentration of the chemicals used (0.1%) and Acetone (1%) the photolytic rate of chlorpyrifos in water was increased by the flowing order PbO > TiO2 > ZnO > Acetone > H2O2. When the concentration decreased to (0.01%) and Acetone (1%) the photolytic rate of chlorpyrifos in water was increased by the flowing order PbO > TiO2 > H2O2 > Acetone >ZnO. When mixing to chemicals the photolytic rate was decreased by the flowing order TiO2 & ZnO < H2O2 & ZnO < ZnO & PbO < TiO2 & PbO < TiO2 & Acetone < H2O2 & PbO < TiO2 & H202...