Persulfate Non-radical Activation By Copper Oxide And Copper Oxide-graphene Composite For Selective Removal Of Refractory Toxic Chlorinated Organic Compounds

Persulfate heterogeneous activation based advanced oxidation processes is an efficient,energy-saving,environment-friendly and cost-efficient technology for refractory toxic organic pollutants,becoming the research hotspot in recent years.The thesis demonstrates the study of persulfate non-radical activation by copper oxide and copper oxide-graphene composite for p-chloroaniline(PCA)and chlorophenols removal.Firstly,non-radical activation of persulfate by CuO was proved by persulfate decomposition study,radical scavenger study and radica identification by electron paramagnetic resonance analysis.The reactive oxygen species was activated persulfate on CuO surface but not sulfate or hydroxyl radicals.Chloride and bicarbonate ions had no effect on PCA degradation in CuOpersulfaet system.The optimal operation pH was neutral and about 70% PCA was removed in 5 hours.Secondly,CuO/graphene composite was investigated for persulfate activation.It was concluded that the formation of Cu-O-C bond between CuO and graphene enhanced the persulfate activation by CuO.CuO/graphene ratio(w/w),composite dosage,solution pH,persulfate concentration and pollutant dechlorination were systematically studied.In experiment condition,PCA and 2,4,6-chlorophenol were almost completely removed in 1 hour and 3 hour respectively.Further study showed that PCA was most easily degraded,followed by 2,4,6-trichlorophenol,2,4-dichlorophenol,trichloroethylene and 4-chlorophenol.Finally,the effect of CuO morphology on persulfate activation was studied.It was conluded that sheet-like CuO was most efficient,followed by spindle-like and sphere-like CuO.By TEM analysis,the(0 0 1)facet-dependent persulfate activation was found.Presulfate non-radical activation could save the oxidant usage by avoiding consumption from radcial propagation reaction,indicating that persulfate oxidation capacity could be fully used.Persulfate non-radical activation system won't be adversely effect by chloride and bicarbonate ions in natural water,and exhibits selective removal ability for pollutants,improving the persulfate usage efficiency and providing a alternative method for specific polluants removal.