热脱附技术在有机磷农药污染土壤修复过程中的应用研究

发布时间：2019-03-13 18:51

【摘要】：天津某农药厂重污染区域土壤中主要以有机磷污染物为主,本研究采用在有机氯、石油烃类等污染土壤修复中已广泛使用的热脱附修复技术,通过实验室试验模拟研究有机磷污染土壤中主要污染物热脱附特征,确立影响土壤有机磷去除效果较佳主导因子及其范围,并在天津某农药厂进行有机磷污染物去除的热脱附土壤修复技术验证试验,为热脱附技术在有机磷污染土壤中推广应用提供技术支持;同时对热脱附后的土壤进行了植物试种验证,为热脱附后土壤的继续利用提供生态学支持。研究主要结果如下:(1)实验室内模拟试验结果表明,热脱附温度和停留时间变化影响有机磷污染土壤热脱附效果,敌敌畏的热脱附较佳温度为200℃,氧化乐果热脱附较佳温度为250℃,对硫磷热脱附较佳温度为400℃。在热脱附30min内,土壤中有机磷污染物的去除率增加显著,30min时去除率都在90%以上,在热脱附停留时间为40min时去除效率达到95%以上。热脱附在低温运行阶段污染物去除率敌敌畏氧化乐果对硫磷。同时土壤粒径大小影响有机磷农药的去除效果,在供试土样粒径范围内,土壤粒径越大,越有利于土壤中有机磷去除。(2)天津某农药厂污染物主要以敌敌畏、氧化乐果和对硫磷为主,通过实验室模拟实验与现场工程验证,本研究所采用的热脱附土壤修复装置能够有效去除有机磷污染土壤中的污染物,对有机磷土壤中敌敌畏、氧化乐果和对硫磷最大去除率分别达到94.3%、97.8%和99.5%,三种污染物在土壤中残留量仅为0.34ppm、0.12 ppm和0.65 ppm,得出农药厂重污染土壤有机磷污染土壤热脱附较佳温度为400℃,停留时间为30min,敌敌畏、氧化乐果、对硫磷的去除率分别达到92%、96.1%、98%。(3)通过对正常土壤处理组、热脱附土壤处理组、有机磷农药土壤处理组试种紫惠槐试验,得出热脱附土壤在经植物修复一个生长季后,紫穗槐的生长状况和根系发育情况与正常土壤上紫惠槐相比无明显差异,根际土壤微环境得到很大改善,且根际土壤中微生物量和酶活性达到正常土壤水平,热脱附土壤生态使用价值与正常土壤差异不明显。与有机磷污染土壤相比,热脱附土壤具有较高的生态使用价值。
[Abstract]:Organophosphorus pollutants are the main pollutants in the heavily polluted soil of a pesticide factory in Tianjin. The thermal desorption and remediation technology has been widely used in the remediation of contaminated soils such as organochlorine and petroleum hydrocarbons in this study. The characteristics of thermal desorption of main pollutants in organophosphorus contaminated soil were studied by laboratory experiments, and the dominant factors affecting the removal efficiency of organophosphorus were determined. In order to provide technical support for the popularization and application of thermal desorption technology in organophosphorus contaminated soil, an experiment was carried out in Tianjin Pesticide Factory to verify the soil remediation technology of removal of organophosphorus pollutants. At the same time, plant seed test was carried out on the soil after thermal desorption, which provided ecological support for the continuous utilization of soil after thermal desorption. The main results are as follows: (1) the results of laboratory simulation showed that the thermal desorption temperature and residence time affected the thermal desorption effect of organophosphorus contaminated soil, and the optimum thermal desorption temperature of dichlorvos was 200 鈩，

本文编号：2439675