| At present, ecosystem contamination from organic pollutants is more and more extensive in cold ecosystems as well as of temperate ecosystems in winter. But, the pollution of snow and ice has not cause enough attention, and studies on the translocation and transformation of contaminations in ice and snow are rare, in addition, the research of the effect of contaminations on the cold ecological environment is also bare. Because the photochemical reaction is the most important path of organic pollutants in snow ice, the research chooses m-cresol as the object which is an important pollutant, and studies laws of photochemical transformation, kinetics and mechanism in liquid water and solid ice of m-cresol. This research may make theoretical foundation for prevention and cure of environmental pollution in ice.Through the indoor simulation experiment, Under the irradiation of UV and simulative sunlight, the research studies on laws of photochemical reaction of m-cresol in liquid water and solid ice where hydrogen peroxide, nitrite or nitrate is added into system, and through the outdoor experiment, under natural sunlight irradiation, the research studies on laws of photochemical reaction of m-cresol in liquid water where hydrogen peroxide, nitrite or nitrate is also added into system The kinetics orderliness is established, In addition, intermediate products produced under UV irradiation are characterized and the possible photo conversion mechanism is proposed accordingly. The experimental results are in the following.The observation shows that in UV system, m-cresol can be transformed directly both in liquid water and solid ice, adding of hydrogen peroxide, nitrite or nitrate into the system accelerates the photo transformation, all reactions obey the first order kinetics model. TOC transformation rate is lower than that of m-cresol in all reactions under UV irradiation. And reaction rate in liquid water is higher than that in solid ice. In the direct photo transformation and system with hydrogen peroxide, the pH value reduces both in liquid water and solid ice. In the system with UV and nitrite, in liquid water experiment, with low concentration of nitrite, pH value also reduces, but with high concentration of nitrite, pH value increases in solid ice experiment, pH value increases. In the system with nitrate, in liquid water experiment, the pH value reduces in solid ice experiment, pH value increases. Results given by GC-MS analysis indicates that in the system UV, UV/H2O2, UV/NO2- and UV/NO3- in liquid water and system UV/H2O2, UV/NO2- and UV/NO3- in solid ice, m-cresol is all transformed into 2-methylbenzene-1,4-diol as the common product. in the system UV/H2O2, the transformation products of m-cresol are mainly hydroxyl compounds, in the system UV/NO2- and UV/NO3-, the transformation products of m-cresol are mainly hydroxyl compounds, nitro compounds and phenols with amino group. The photochemical transformation products of m-cresol in solid ice are of many kinds, of heavy molecular weight and of complicated structure. The results suggest that the photo transformation of m-cresol in solid ice and liquid water is different in certain aspects.The results show that under irradiation of simulative sunlight, m-cresol can be transformed directly both in liquid water and solid ice, adding of hydrogen peroxide, nitrite into the system accelerate the photo transformation, Adding of nitrate prohibits the photo transformation. and except the photochemical transformation of m-cresol with nitrate in solid ice, all the reaction obeys the first order kinetics model. The pH value in each system is little changed.The experiments under natural sunlight irradiation in liquid water show that under the effect of sunlight and sunlight/NO3 - m-cresol is hardly transformed. But in the system with hydrogen peroxide or nitrite, m-cresol can be transformed, but the transformation rate is lower than 15%, the reaction obeys the first order kinetics model. The pH value in each system is also little changed.
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