Fe^0/H_2O_2类Fenton体系降解水中对氯硝基苯

Degradation of para-chloronitrobenzene by Fe^0/H_2O_2 Fenton-like

为解决传统Fenton过程中Fe3+返回Fe2+速率慢致使反应过程中铁离子循环受阻的瓶颈问题,对Fe0/H2O2-类Fenton降解对氯硝基苯(pCNB)的效果与机理进行研究.考察H2O2和铁的投加量、初始pH值等因素对pCNB降解效果的影响,对体系TOC和Cl-、NO3-浓度以及一些中间产物进行鉴定和分析.当pH值为5,铁、H2O2、pCNB初始投量分别为200、3.5、20 mg/L,反应20 min时,Fe0/H2O2类Fenton体系能将pCNB去除73%.在相同pH值、铁和H2O2投加量情况下,Fe0/H2O2-类Fenton法对pCNB的降解效率比传统Fenton法高20%～30%,pH值在3.5～7.0内,该体系对pCNB都具有很好的降解去除作用.pCNB在降解过程中没有被完全矿化,苯环上的—Cl和—NO2也没有完全转化为无机离子,主要中间产物为草酸、羟基乙酸、乙酸、马来酸、对硝基酚、对氯酚、2-氯-5-硝基酚、5-氯-2-硝基酚等.

Para-chloronitrobenzene degradation by Fenton-like with zero-valent iron and hydrogen peroxide was studied in depth for the purpose to solve the circulation of iron ions suffocated caused by the slow rate of Fe3＋ returns Fe2＋ in the traditional Fenton reaction.Different effects of hydrogen peroxide and iron dose,initial pH value and others factors were investigated.Para-chloronitrobenzene removal efficiency of 73% was achieved under optimal reaction conditions of pH value 5,with dosage of 200 mg/L zero-valent iron,and 3.5 mg/L of hydrogen peroxide after 20 min.The Removal efficiency of para-chloronitrobenzene by Fe0/H2O2 Fenton-like increased 20%-30% than the traditional Fenton reaction under the same dosage of iron and hydrogen peroxide,and the same of pH value.And in 3-7 range of the pH value,para-chrornitrobenzene degradation effects were obvious by Fe0/H2O2 Fenton-like.The choro-（—Cl） and nitro-（—NO2） on the phenyl were transformed inorganic ions incomplete.The main intermediates were oxalic acid,glycolic acid,acetic acid,maleic acid,p-nitrophenol,p-chlorophenol,2-chloro-5-nitrophenol,5-chloro-2-nitrophenol.An degradation pathway of the para-chloronitrobenzene was also proposed.