Fenton氧化技术修复六氯环己烷污染土壤特性研究

Remediation characteristics of HCHs in contaminated soil by Fenton oxidation

为研究六氯环己烷(HCHs)在污染土壤中的Fenton氧化特性及其影响因素,以中国西南地区已停产的某HCHs生产企业厂区的污染土壤为研究对象,分析Fenton氧化作用下Fenton氧化时间、催化剂种类、催化剂投加量和H_2O_2投加量等因素对HCHs去除率的影响。结果表明:(1)延长Fenton氧化时间可以促进HCHs的去除,其去除率在100min后达到稳定;Fe^(2+)的催化效率优于Fe^(3+)和Fe^0,最佳催化剂为FeSO_4·7H_2O晶体;催化剂投加量最佳为5%(质量分数);较高投加量的H_2O_2有利于产生更多的HO·,H_2O_2投加量最佳为20g/mL。(2)Fenton氧化对HCHs的去除机制具有一致性,但不同HCHs异构体的去除率存在差异。在以FeSO_4·7H_2O晶体为催化剂、Fenton氧化时间为100min、催化剂投加量为5%、H_2O_2投加量为20g/mL的最优条件下,β-HCH去除率最高(96.7%),α-HCH去除率次之(79.2%),γ-HCH和δ-HCH去除率分别为54.8%和51.3%。(3)Fenton氧化技术是一种优秀的HCHs污染土壤修复技术,具有较高的可行性、经济性和环境友好性,具有较大的HCHs污染场地原位修复应用前景。

To investigate influence factors and oxidation characteristics of HCHs with different isomers in contaminated soils under Fenton,examples collected from a suspended HCHs manufacturer in southwest China were employed for experiments. Such Fenton oxidation factors as reaction time, catalyst type,catalyst content and H2 O2 concentration were taken into account for the HCHs Fenton oxidation. The results indicated： （1） HCHs could be effectively remediation in contaminated soil. In a certain degree, the increase of the reaction time could enhanced the removal rate towards a stable status at 100 min; the removal rate of Fe^2＋ catalytic efficiency was better than that of the Fe3＋ and Fe^0 , the optimum catalyst type was FeSO4 · 7H2O;the oxidation of the HCHs was improved by raising the catalyst content whose optimum value was 5% ;high concentration of H2O2 concentration could produce more HO·,the oxidation of the HCHs was also improved by raising the H2O2 concentration whose optimum value was 20 g/mL. （2） Different HCHs isomers exhibited different oxidation performances. The best removal rate 96.7% was tested from β-HCH, followed by 79.2 % from a-HCH, while the removal rate of γ-HCH and β-HCH were respectively 54.8 % and 51.3%. （3） Fenton oxidation technology was a kind of excellent HCHs contaminated soil remediation technology, which had a high feasibility, economy and environmental friendliness. A great potential for HCHs contaminated site remediation had been established.