Studies On Degradation Of Chloro-aromatic Compound In Wastewater By Ultrasound Cooperated With Zero-Valence Iron

In this article, degradation of 2,4-dichlorophenol and m-dichlorobenzene by US/Fe0 were studied. Influence of the mount of zero iron powder, the initial concentration and pH of solution was detected by one factor experiment. Relation between chloroaromatics and their structures, degradation dynamics and synergic effect of US/Fe were also studied.The study results indicated the synergic effect of US/Fe was notable. The best experiment conditions of degradation of 2,4-dichlorophenol was got, namely the best mount of iron powder was 1.2g/L～1.6g/L, the best pH was the lower pH value and the best initial concentration is the lower initial concentration. The best experiment conditions of degradation of m-dichlorobenzene was got, namely the best mount of iron powder was 1.5g/L, the best pH was 2 and 10, and the lower initial concentration, the better degradation rate would get. All the results showed that degradation of chlorophenols and chlorobenzenes in US/Fe system followed the first order dynamic reaction. Degradation rate followed the falling order: PCP> 2,3,4,6-TeCP> 2,4,5-TCP> 2,4-DCP> 2-CP, 1,2,4-TCB> O-DCB> M-DCB> P-DCB > CB. The more chlorine atoms, faster the chloroaromatics were removed from the water by US/Fe0. For the isomers of dichlorobenzene, the oxidation rate of isomers is different. The number of position of O-DCB, M-DCB and P-DCB that could be attacked by oxygen is 3, 2 and 1 respectively.Synergic effect of ultrasound and iron origin from the following 3 aspects: Firstly, grain effect of iron powder;Secondly,catalysis of Fe2+;Thirdly, purge of surface of iron powder by US.