Studies On Distribution-Release Regularity And Photodegradation Of Phenol In Ice

Photochemical reaction plays a major role in the environment.Solar light is involved in a large number of reactions in the atmosphere,in natural waters,on soil,and in living organisms.Photochemical activation is the principal driving force of transformations of organic substances in the atmosphere and it plays a significant role in the degradation of compounds which are inefficiently biodegraded in surface waters.Knowledge about the (photo)chemical changes,that can occur in frozen water,is still quite limited.However,it seems that scientists have started to pay more attention to this problem in the recent years.And realize the ice as the importance of the potential pollution sources in the environment gradually.Over the past several years there has been a growing concern about the chemical composition of snow pack and ice cores in polar regions.Snow and ice are important components of cold ecosystems as well as of temperate ecosystems in winter and they undoubtedly influence the fate and behaviour of PBTs.Because of the special properties of the snow and ice,with respect to the liquidity atmosphere and water body,pollutant physics internal of the snow and ice physical migrating process,conventional chemical reaction and microbc actions,is weak relatively.Whereas,the chemical action with the lesser role by temperature demonstrates special importance. Preliminary researches at present indicate mere chemical action can transform some organic matter to PBTs in the snow and ice,which can make the snow and ice potential polluntion sources.So,the photochemistry of the organic pollution has very importance significance in the snow and ice.Today especially,the climate becoming warmer and warmer increasingly, organic pollution in the snow and ice resulting photochemical products,when glacier melting,may bring another environmental problem.But people have reachered to the transform of organic pollution photochemistry of ice,snow process study rarely at present yet,the research in this respect also belongs to a new field.Preliminary researches indicate photochemistry research and atmosphere and water environment photochemistry research to ice looks have equally important significances.This thesis regards phenol as the research object.Study the distribution and release law of phenol in the ice when ice melt.Simultaneously in the -10℃refrigerator,adopting the spontaneous designing low-temperature photochemical reaction device,after the irradiation of 125W high-pressure mercury lamp,discuss on photodegradation mechanism of phenol in ice.Finding in the experiment,different density phenol (10mg/L,50mg/L,200mg/L) distribution that ice takes a fancy to whether density value reach minimum outer ice-cubes in solid state,it is the biggest inner.And the density value of layer should be higher than the initial value of the solution. Observing the system the lower in density at the same time,the better the result of purifying of the ice is.The influence on releasing of different density is,as the increase release amount of time is reduced rapidly,a large amount of phenol coming out fast release within short time,releasing evenly subsequently.pH takes a fancy to the release of the solution of 50mg/L phenol (initial pH=6.59) of great impact to the ice. Gentlely,releasing amount reduces gradually with increasing time on the whole,but releasing of phenol not so good as curvilinear motion pH transferring.As to the influence that different density distributes in the ice-water to benzene,observing in the experiment,the solution distribution coefficient in the frozen course of phenol presents the trend reduced on the whole by increasing density.When 10mg/L,distribution coefficient of ice-water reaches maximum 0.19,and reach the minimum 0.08 when 170mg/L,i.e. what phenol assigned in the ice is less.This conclusion of distribution experiment in good agreement with the experiment of distribution result,which is that water purifies agrees to be frozen.Regarding 125W high-pressure mercury light as the light source indicates on mere degradation of phenol in the ice: degradable time only in selected 6h,100mg/L phenol of degradation in solid ice is the first-order kinetic law.The surplus rate of TOC is higher than the surplus rate of phenol all the time within complex reaction time in the experiment. Inferring when phenol photolytic may have produced other organic matter at a while.Also find in the experiment that produced the reddish brown sediment while the light degraded at the same time.Analyzing and finding GC-MS to solution and sediment after degrading separately,the solution after degrading has not found the obvious products.Obviousing product peake that appears in the sediment table picture after dissolving,and inferring their products is oxydibenzene and biphenyl-2-ol according to the picture data of mass spectrum.In sum,studying the releasing and distribution of phenol in ice,and the photochemical reaction of phenol in the ice of solid state,facilitate further understanding of phenol in ice to potential impact of the ecological environment,therefore it is more important for environment protection meanings.