Effects Of Hydroxyl Radical On The Photochemistry Of Phenol In Ice-phase

Because of the special nature of ice, compared to the flow of air and water, pollutants in the ice have weekly physical relocation process, conventional microbiological and chemical reactions, and photochemical role that less affected by temperature showed special importance. Preliminary studies indicate that the organic pollutants in the ice through the photochemical reaction might be transformed into secondary pollutants, and ultimately through the ice melting and evaporation, or release into the environment, so as to pollute the environment. Therefore, in-depth study of the ice phase photochemical effects of organic pollutants has very important significance. Because hydrogen peroxide in the light conditions can be decomposed into hydroxyl radicals, and hydroxyl radicals can react with almost all the substances, and the reaction rate soon, become to the non-radical reaction, thus change the material in the ice core ,and even transfer some organic pollutants in snow and ice into harmful substances that can be easily absorbed by human and animal through the chemical role . The photochemical product in ice has potential hazards to the environment .With the melting of ice in the presence these harmful substances will pollute the environment through various channels. But now the light degradation of organic matter with common oxidants on the snow and ice conditions exist under the hydroxyl radical mechanism of the reaction has not yet had the standard model .Therefore, the hydroxyl radical phase of the ice-degradation of organic matter for the significance of environmental protection to a certain extent.We studies phenol degradation by the light under different conditions in the ice phase in this research, As well as when the strong oxidant hydrogen peroxide presents, the phenol degradation by the light under different conditions in the ice phase. In view of phenol and dimethyl sulfoxide specific absorption curve, We will use for the reactor through wavelength> 280 nm glass tube, in the self-made experimental device, the researchers in different concentration, pH, light intensity and ion conditions, obtained of the influence of hydroxyl radical to phenol degradation by the light under different conditions. In our study it is found that photo-degradation of phenol is different under different conditions among different phenol systems (solid ice-phase phenol system and solid phenol-peroxide system). Under different pH, solid ice-phase phenol system has a higher degradation rate under strong acidic or alkaline conditions, while these conditions would inhibit the degradation of the solid phenol-peroxide system, and weak acid or alkali would enhance the degradation of solid phenol; The degradation of both systems accelerates with the intensity of light increases. when filled with nitrogen, the degradation would insignificantly enhance. The addition of Fe2+,CO32-,HCO3-,NO2- could enhance the degradation of ice-phase phenol, while NO3- would inhibit it. With peroxide existing, the addition of Fe2+could enhance the photo-degradation of ice-phase phenol, while CO32- HCO3- had no impact to the degradation of ice-phase phenol; NO2-,NO3- would inhibit the photo-degradation of ice-phase phenol, SO42- does not have an effect. It is indicated that the change of hydroxide in the system has an effect on the degradation of phenol. Finally according to the kinetics equation, the hydroxide from the decomposing of peroxide could significantly shorten the degradation time of phenol.Through the study of dimethyl-sulfoxide (DMSO)-phenol system,it can be concluded that, the amount of HO under strong acidic or alkaline conditions is less than that under weak acidic or alkaline conditions. With the intensity of light increases, the HO?production increases. When filled with nitrogen and oxygen,HO ? production is inhibited. Different ions in the solution have different effects on the HO production. Fe2+ would enhance the production of HO?, HCO3-,CO3-,NO2, NO3- would inhibit the OH production, and SO42- has almost no effect on the OH production.