Simultaneous pentachlorophenol deocmposition and granular activated carbon regenertion assisted by microwave irradiation

摘要

This paper describes an integrated granular activated carbon (GAC) adsorption/microwave(MW) irradiation process used for the treatment of high concentration pentachlorophenol(PCP) wastewater.Firstly,PCP in water was adsorbed onto GAC,then the PCP was deocmposed and GAC regenerated by NW irradiaton.The liquid and gas produced during irradiation were collected through condensing,and absorbed by a 0.1 mol l~-1 NaOH solution,respectively.The detrmination of the PCP concentrations in the distillate,absorption solution and GAC was accomplished by a HPLC.The results suggestd that when irradiated with 850 W MW for 10 min,most of the PCP adsorbed by GAC and whatever fragments frome dwere decomposed to CO_2,H_2O and HCl or tightly bound to GAC,and less than 2 of PCP was transformed into intermediates in the distillate.Some dechlorination and dehydroxylation products were identified by the GC/MS analysis,and the degradation mechanism was proposed.It was also confirmed that GAC could be resused after several adsorption/MW regeneration cycles and its adsorption capacity could maintain a relatively high level,even highe rthan that of virgin GAC,as indicated by BET results,iodine values and PCP adsorption isotherms.