| Ice and snow are independent and complete low temperature environment system and mainly exists in area of high latitude and high elevation. Along with high speed of chemical industry development, causes producing large amount of organic matter entering into atmosphere, river, lake, ice and snow. Snowfall may be able to clear away the organic compound of gaseous state in atmosphere and adsorbed on particulate matter and through forming seasonal and permanent ice and snow, as prevent organic compound of volatility continuously moves and changes among the atmosphere, water body, soil, polar region and etc. environment. Now people do not know enough about organic matter moving and changing law in ice and snow, after ice and snow melting (especially along with green-house effect aggravating and bringing along ice and snow melting on polar region) for the influence of around ecological environment, research on ice and snow pollution does not lead to peoples special attention and the research on the course of pollutant moving and changing in ice and snow and which may causes influence on ecological environment are seldom. Because of special characters of ice and snow, relative to atmosphere and water body of mobility, pollutant physical moving course in the inner of ice and sow, routine chemical reaction and microorganism effect relatively weak, but photochemistry influenced less by temperature shows special importance and research on this field belongs to a newer domain. Research on distribution law of organic pollutant in solid ice and when ice melting organic pollutant release law, will be conducive to know organic pollutant actual distribution state in ice for us. Owing to possessing resistance of wide spectrumdisinfection, makes a great amount of chlorophenol kind of pollutant entering into environment and has caused serious harm to natural environment. The chlorophenol chemical compound polluted area is wide. Chlorophenol matter which are measured in soil, sediment, solid discard material, sludge, groundwater and surface water. The article takes 4-chlorophenol as research object, it is important raw material of synthetic material, healing drugs and pesticide, exists widely in each kind of waste water, it does not possess benzene ring but also typical subsistent group. Experiment research its distribution and release laws in ice system, measure 4-chlorophenol distribution coefficient between ice-aqueous phase, investigates consistency influences on distribution and release coefficient of ice-aqueous phase, measure light degradation speed constant and has done inferences for light degradation mechanism.Experience states clearly: (1) Distribution law: The biggest value of consistency of 4-chlorophenol in ice is all in the most inside of ice lump, but outside consistency value is the lowest. Along with the different chlorophenol solution consistency (10mg/L, 50mg/L, 200mg/L), there is no influence on change trend of distribution law;(2) Release law: a) the preliminary melting time, 4-chlorophenol release consistency is the biggest, along with the time prolonging, the consistency of release 4-chlorophenol becomes less and less follows the same release law in experience consistency range. When releasing course ending, the last releasing consistency becomes lower and is lower than consistency of initial solution, Along with different consistency of 4-chlorophenol solution (10mg/L, 50mg/L, 200mg/L), there is no influence on change trend of release law; b) After through regulatin pH value, release law change, at the first, release consistency fluctuates in a small range, fairly stable, along with the time prolonging, appears the highest point of release consistency, then again low, but along with pH value increasing, the highest point of release consistency gradually moves up from 700 min to 500 min;(3) Distribution coefficient between ice and aqueous phase: Along with consistency increase (10mg/L increasing to 200mg/L) distribution coefficient of 4-chlorophenol in ice and aqueous phase change between 0.1~0.2. The proportion volume of ice and water is nearly 1:1 and consistency dose not greatly influence on distribution coefficient;(4)Taking 125-W high-pressure mercury lamp as light resources, 100mg/L 4-chlorophenol ice light degradation for 3 hours, from degradation curve, we can see clearly that 60 minutes before degradation and degradation rate is higher than the later stage. This may be the beginning of reaction, absorption light of 4-chlorophenol splits for phenolic group and chlorine atom, phenolic group may produce polymerization reaction with suitable aromatics polymerizing reaction, when UV radioactive energy has been dispersed in 4-chlorophenol and formed intermediate product and speed of reaction speed drops. 3 hours depredates 96% 4-chlorophenol and research balance. 4-chlorophenol light degradation speed accord with class A dynamics model. The experiment measured to TOC degradation rate only reach 35.8%, pure light degradation had no way to make 4-chlorophenol in ice completely reach mineralization. After degradation, reactive liquid centrifuged gets sediment and carries on GC-MS analyzes, indentificates production of 5-chlorobipheny1-2,4'-diol and inferences degradation mechanism of 4-chlorophenol in ice.To sum up above, in ice, 4-chlorophenol distribution and release is not distributed equally, photocatalysis produces diphenol, and light degradation course dose not completely mineralizes 4-chlorophenol in ice. People more and more pay special attention to chemical composition in snows and ice nucleus, then can know moving and change laws of organic matter in ice and snow and do relative measure to prevent and remedy environmental pollution which it had brought about or will bring. At same time people may know human activities leave pollutant mark in ice and snow and so inquire into the relation of organic matter in ice and snow with environmental ecology, climate change and human activities. |
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