泥浆相电芬顿修复芘污染土壤及其特性分析

Remediation of pyrene-contaminated soil using electro-Fenton in a slurry-phase:the characteristics analysis

应用泥浆相电芬顿修复芘污染土壤,对关键参数进行优化,并对泥浆相电芬顿反应特性进行分析.研究了泥浆相电芬顿的曝气量、pH值、电压梯度对羟基自由基生成和芘降解的影响,并通过对土壤缓冲能力、芬顿试剂的原位产生、土壤有机质、土壤水分分配系数、表面张力和不同土壤粒径分布等参数的测定分析,阐述泥浆相电芬顿反应特性.结果表明,在最佳反应条件下(曝气量为500mL/min,初始浆液pH值为3.0,电压梯度为2V/cm),芘降解率为81.83%,羟基自由基浓度为36.65μmol/L.土壤较强的缓冲能力,使得反应后期通过调整pH值的方式提高反应效率不可行,而应增加H_(2)O_(2)浓度.在S-EF处理过程中土壤有机质总量降低,胡敏酸和富里酸的含量也降低,对芘的吸附能力降低.同时,从泥浆的表面张力以及芘在泥浆中固液分配系数的变化可知,泥浆相电芬顿促使芘从吸附态到解吸态转移,芘降解率显著提高.因此,泥浆相电芬顿技术是一种有效的有机污染土壤修复技术.

The electro-Fenton(EF)process is a promising technology for removing contaminates from soil or water.However,there are many differences between soil and water during the EF remediation process.Therefore,the effect of EF process on the remediation of pyrene in contaminated-soil by a slurry-phase was investigated,especially the effect of the optimum parameters on hydroxyl radical(·OH)generation and pyrene degradation,including soil organic matter,soil-water distribution coefficient(K p),surface tension and different soil particle-size.The results demonstrate that under optimum operating conditions(an aeration rate of 500mL/min,initial slurry pH of 3.0 and voltage gradient of 2V/cm),pyrene degradation of 81.83%and·OH concentrations of 36.65μmol/L were achieved.Both the content and the composition of the soil organic matter changed,with the changing of distribution of pyrene.Moreover,it showed a lower degradation of pyrene and a lower generation of·OH during the latter period of the experiment,because of the change of pH and H_(2)O_(2).In addition,the mass transfer of soil was enhanced by the slurry-phase system.And the high degradation of pyrene(89.26%)on the fine particle-size(<0.005mm)of soil had occurred.Ultimately,these results have shown that incorporating the EF process into a slurry-phase reactor will create an efficient technology for the remediation of organic-polluted soil.