摘要:
采用提纯凹凸棒土(ATP)负载纳米零价铁(nZVI)制备得到改性材料ATP-nZVI,将其用于对地下水硝酸盐的去除研究。通过静水实验考察了溶液中共存阴离子和反应温度对ATP-nZVI去除NO3--N的影响,通过模拟可渗透反应墙(PRB)考察了溶液初始pH、初始NO3--N浓度、材料装填方式、流速对ATP-nZVI去除NO3--N的影响,并通过更换PRB装填材料将ATP-nZVI与石英砂、ATP、铁粉、nZVI等材料对NO3--N的去除效果进行了比较。结果表明:共存阴离子对ATP-nZVI去除NO3--N具有抑制作用,其抑制作用的顺序为PO43->CO32->SO42->Cl-;ATP-nZVI对NO3--N去除率与反应温度呈正相关,但总体来讲其受温度变化的影响并不明显;同一pH条件下,ATP-nZVI对NO3--N去除率随着硝酸盐溶液质量浓度的增大而减小;对于相同质量浓度的硝酸盐溶液,相比在中性和碱性环境,其在酸性条件下NO3--N去除率较高;ATP-nZVI的装填层数越多,对NO3--N的去除率越高,长效性也越好;流速越大,ATP-nZVI对于NO3--N的去除率越小,效果越差;PRB柱填充不同材料时的去除效果为ATP-nZVI>nZVI>铁粉(200目,即74 μm)>ATP>石英砂,ATP-nZVI作为PRB的填充材料时,系统对NO3--N的去除稳定性与去除率得到有效提升,具有良好的实用性。机制研究表明,ATP-nZVI对NO3--N的去除主要归因于nZVI的还原作用,而ATP对于nZVI的负载则加强了这种还原作用。
关键词:
凹凸棒土,
纳米零价铁,
反应渗透墙(PRB),
硝酸盐
Abstract:
Modified material ATP-nZVI was prepared by purifying attapulgite(ATP) loaded with nano-zerovalent iron(nZVI) and was used to remove nitrate from groundwater. The effects of anions in the solution and reaction temperature on the nitrate removal by ATP-nZVI were investigated by hydrostatic experiments. The effects of initial pH,initial nitrate concentration,material loading method and flow rate of the solution on the nitrate removal by ATP-nZVI were investigated by simulated permeable reaction wall(PRB). The nitrate removal effect of ATP-nZVI was compared with that of quartz sand,ATP,iron powder and nZVI by replacing the PRB loading materials. The results showed that the coexisting anions inhibited the removal of NO3--N by ATP-nZVI,and the inhibition sequence was PO43->CO32->SO42->Cl-. The removal rate of NO3--N by ATP-nZVI was positively correlated with reaction temperature,but it was not significantly affected. At the same pH,the removal rate of NO3--N by ATP-nZVI decreased with the increase of the mass concentration of nitrate solution. For nitrate solution with the same mass concentration,the removal rate of NO3--N was higher under acidic conditions than in neutral and alkaline environments. The higher the number of ATP-nZVI filling layers,the higher the nitrate removal rate and the better the long-term effectiveness. The higher the flow rate,the smaller the removal rate of nitrate by ATP-nZVI,and the worse the effect. When PRB column was filled with different materials,the removal effect was ATP-nZVI>nZVI>iron powder(200 mesh,74 μm)>ATP>quartz sand. When ATP-nZVI was used as the filling material of PRB,the removal stability and removal rate of NO3--N in the system were effectively improved,which had good practicability. The mechanism study showed that the removal of nitrate by ATP-nZVI was mainly attributed to the reductive action of nZVI,and the load of ATP on nZVI strengthened the reductive action.
Key words:
attapulgites,
nano-zerovalent iron,
reaction penetration wall(PRB),
nitrate
中图分类号:
张笑天, 张阳阳, 祖波, 张云霞, 陈克军. 改性纳米零价铁去除地下水硝酸盐的研究[J]. 工业水处理, 2023, 43(3): 87-95.
Xiaotian ZHANG, Yangyang ZHANG, Bo ZU, Yunxia ZHANG, Kejun CHEN. Research on nitrate removal from groundwater by modified nano-zerovalent iron[J]. Industrial Water Treatment, 2023, 43(3): 87-95.