Study On The Adsorption Characteristics Of Odorous Substance Of Powdered Activated Carbon Of Different Grain Diameter Sizes

With the rapid development of our society, especially the development of industryand more and more arbitrary discharge，causing serious pollution of rivers and lakes.The algae of large number not only consume of dissolved oxygen in the water, but alsorelease the odorous substance, causing outbreaks of different smell problem in drinkingwater and the drastic increase of poisonous and harmful chemical components, leadingto serious threat to the security of urban water supply. In order to solve this problem，use powdered activated carbon of different grain diameter sizes to remove odorsubstances in water （2-MIB and Geosmin）, and study their adsorption characteristics,providing theoretical basis for practical application.When water source polluted by odor substances, add powdered activated carbon isan economic, effective emergency treatment for water. This article especially study onthe adsorption characteristic of the different size powered activated carbon, including:（1）Study on the adsorption capacity, adsorption thermodynamics and dynamics effect ofthe different size powered activated carbon for2-MIB and Geosmin;（2）Analyzingvariations of molecular weight（MW） distribution of dissolved organics in HeiheReservoir and Shibianyu Reservoir and the adsorption characteristic of organic matterand odor substances of different size powered activated carbon;（3）Study on the effectof treatment for the water in Shibianyu Reservoir by the PAC-coagulation.The main conclusions were listed as follows:（1）Powered activated carbon has good results for removing2-MIB and Geosmin.With the size of powered activated carbon decreasing, it means as increase of （s） thesepcific surface area of Powered activated carbon,adsorption characteristic of thepowered activated carbon is better. Adsorption kinetics study shows that the main adsorption of2-MIB and Geosmin by powered activated carbon happened at the first30min, the removal rate of2-MIB of600head of activated carbon can reach95%,almost reach adsorption equilibrium; the removal rate of400,300,200head poweredactivated carbon is85%,60%,51%. The second-order adsorption kinetics can be betterfitting2-MIB and Geosmin adsorption process; Adsorption isotherms research showsthat Freundlich adsorption isotherms model is better fitting2-MIB and Geosminadsorption process than the Langumir adsorption isotherms model.（2）Dissolved organic matters in Shibianyu Reservoir is main between zero and4000Da, and account about60%between2500and4000Da.That is humic acids, fulvicacids and hydrophilic organic acids and other small molecules,main from metabolism ofalgae and aquatic plants and released soil organic matter. Dissolved organic matterswith low molecular weight and high molecular weight are two main components inHeihe Reservoir. The part of high molecular weight is between18wDa－20wDa，takeup total molecular weight of43%.The part of low molecular weight is between3500Da－2000Da，Account about40%of total molecular weight.The rate of removal of Geosmin in Shibianyu Reservoir and Heihe Reservoir byPAC is72%, up to78%in distilled water. The removal of2-MIB in ShibianyuReservoir and Heihe Reservoir by PAC rate up to70%and75%, and rate up to83%indistilled water.（3） Add two different types of coagulants in raw water of coagulation experiments,Al₂（SO）₃is better than PAFC in removal UV₂₅₄, COD_Mnfrom water,but for turbidityremoval, the removal rate of PAFC is higher than Al₂（SO）₃.As the decrease ofactivated carbon particle size, and increase of the amount of active carbon, removal rateof UV₂₅₄and COD_Mnfrom water increase.When the volume of active carbon is5-30mg/l,the rate of removal of UV₂₅₄by200head PAC increase from2.7%to14.3%, and COD_Mnremoval rate increase from2.9%to14.9%. the rate of removal of UV₂₅₄by600head PAC increase from14.3%to33%,and COD_Mnremoval rate increase from11.6%to19%.The removal rate of UV₂₅₄and COD_Mnin raw water by the same surface areaactivated carbon is different. When use600head powdered activated carbon carryingout experiments, in less than200head powdered activated carbon addition of5.3mg/l, dosing3mg/l less than400cases, its removal rate is still higher than in the other twosize a lot.