蔗糖改性纳米铁原位反应带对硝基苯污染的模拟修复研究

在一维模拟装置中创建改性纳米铁原位反应带,研究反应带对硝基苯污染的修复情况,并通过反应带渗透性变化对其可持续修复能力进行评估.模拟试验结果表明:不同条件下硝基苯的去除率为45%~80%;反应带渗透性变化过程按时间分为3个阶段,分别是0~10d的快速下降期、10~30d的缓慢下降期和30~60d的稳定期,平均下降了53.2%,堵塞现象未发生,反应带可持续修复能力较好.较大的介质粒径和浆液浓度使污染物降解效率增加,硝基苯去除率可分别提高23.7%和13.7%;较高的地下水流速和污染物浓度不利于污染物的去除,硝基苯去除率均下降约46.8%.各反应带中实际参与反应的铁与硝基苯的物质的量比值分别为11.2、17.9、12.6、3.3和25.7,改性纳米铁颗粒的实际利用率较低,实际应用中浆液需要过量注入.

Simulated remediation for nitrobenzene pollution with in-situ reactive zone of sucrose-modified nanoscale zero valent iron

In order to study the remediation effeciency for nitrobenzene pollution, in-situ reactive zone of modified nanosale zero valent iron was created in one-dimensional simulation columns using prepared slurry, and the persistence of its function was also assessed through the calculation of permeability change. The results of simulated experiments show that the removal efficiency of nitrobenzene was 45%~80%, and the changing process of the permeability of the reactive zone could be divided into thress stages: rapid decline in 0~10d, slow decline in 10~30 d and stable stage in 30~60d with average decrease of 53.2%. Still, the reactive zone kept favourable operation without blocking in different aquifer conditions, which proved that the zone of SM-NZVI could continue to remediate availably. Larger particle size of aquifer medium and suspension concentration resulted in higher degradation efficiency of nitrobenzene which increased by 23.7% and 13.7%, respectively. However, higher flow velocity of underground water and pollutant concentration were adverse to the removal of nitrobenzene which both decreased by 46.8% or so. The ratio of iron to nitrobenzene participating in the reaction actually in each zone was 11.2, 17.9, 12.6, 3.3 and 25.7, respectively, it means that the utilization percentage of SM-NZVI particles was relatively low and thus excess suspension should be injected to the underground for ideal remediation results.