本文对Fenton法与类Fenton法降解土壤中的二苯砷酸(diphenylarsinic acid,DPAA)进行了研究.考察了H2O2投加量和催化剂种类(Fe2+/Fe3+)对红壤及黑土中DPAA降解效果的影响,并采用高效液相色谱-质谱联用法(HPLC-MS/MS)对降解中间产物进行了初步鉴定.结果显示,针对红壤与黑土分别采用类Fenton法与Fenton法,在H2O2投加浓度为1 mol·L-1,含铁催化剂浓度为0.25 mol·L-1,土水比为1∶3,反应时间为1h的条件下,红壤及黑土中DPAA的降解率均可达到65%以上.HPLC-MS/MS的分析结果表明,DPAA可脱苯环形成降解产物苯砷酸(phenylarsinic acid,PAA),而PAA进一步氧化生成无机砷,这可能是Fenton/类Fenton法降解DPAA的途径之一.
Degradation of diphenylarsinic acid( DPAA) in soil by Fenton and Fenton-like reactions was studied in this paper. The influence of H2O2 dosage and catalyst species( i. e.,Fe2 +,Fe3 +)on the degradation efficiency of DPAA in Acrisol and Phaeozem was investigated. High performance liquid chromatography coupled with tandem mass spectrometry( HPLC-MS / MS) was employed to identify the degradation intermediates. The results showed that under the preparation conditions of initial H2O2 dosage of 1 mol·L- 1,iron catalyst dosage of 0. 25 mol·L- 1,soil-water ratio of 1∶ 3 and reaction time of 1 h,more than 65% DPAA in Acrisol and Phaeozem were removed by Fenton-like oxidation and Fenton oxidation. HPLC-MS / MS analysis demonstrated that DPAA was degraded to phenylarsinic( PAA) by dephenylation, and subsequently partially oxidized to form inorganic arsenic,which may be one possible degradation pathway of DPAA during Fenton and Fenton-like reactions.