Activated Carbon Electricity Adsorption Treatment Of Chloroform In Water

THMs, mostly chloroform, are motored in drinking water in many countries including China, Japan, and America. Some researches indicated that THMs are carcinogen, and they resulted from the reaction of humus with chlorinate, which is from the drinking water being chlorinated. THMs must be preferentially removed for their carcinogen.Many people take in the researches on methods of removal such chemicals. Adsorption on activated carbon is a better and effective way for chloroform. However, the usual adsorption on activated carbon is costly and activated carbon need regenerated. If we can find a way to artificially enhance the adsorption of activated carbon, its benefits on economy and environment will be considerable.It is the aim of this work to investigate electrosorption of chloroform in water on granular activated carbon. The potentials on working electrode are controlled by potentiostat and the concentration of chloroform is measured by headspace gas chromatography. Adsorption isotherm and adsorption kinetics of granular activated carbon are measured in order to obtain specific information about the influence of the charge on the absorbability of chloroform. The influence of the bed potential on the adsorption equilibria shows a dependence on applied potential in electrolyte of approximately O.lmol/L ionic strength. With electrosorption from aqueous solution, 60% enhancement of the concentration in one controlled potential is achievable. The valve of PH is hardly changed during the process of electrosorption and adsorption. Potentials anodic to EPZC increase the amount adsorption and the rate of adsorption. However, potentials catholic to EPZC decrease the adsorption capacity of the granular activated carbon. That is to say, with the increase of controlled potentials from -SOOmV. -SOOmV, -lOOmV, OmV, lOQmV, 300mV,to SOOmV vs.Sat.RE, the amount adsorption and the rate of adsorption is increased.The fundamentals of electrosorption on granular activated carbon for water treatment are discussed. The configuration and net atomic charges of chloroform are calculated with PM3 calculation by MOPAC2000. On the whole, the surface charge of chloroform is negative. Thus, both the adsorption capacity of granular activated carbon and attractive or repulsive forces of charge influence the electrosorption of chloroform on granular activated carbon.The redox potentials of chloroform are more than 500mV and electrosorption is only controlled by electric field and adsorption of granular activated carbon. The tests of adsorptions also testify it. The Freundlich isotherm equation Q=KC n is used for fitting the data. Here, n=l. In all cases, the adsorption equilibria show a strong dependence on the applied potentials, K= 0.001V+0.92,K is the consistent of Freundlich isotherm equation; V is the controlled potentials WE vs. RE.