垂直流人工湿地MgFe-LDHs覆膜改性基质净化效果研究

选取生物陶粒、无烟煤、沸石3种垂直流人工湿地常用基质,采用金属摩尔比(M2+ : M3+)为2:1的MgCl2溶液和FeCl3溶液在碱性条件下共沉淀即时生成MgFe-LDHs,并将其覆膜于所选3种垂直流人工湿地基质表面;构建模拟基质试验柱,对改性前后的6种基质进行垂直流人工湿地模拟柱净化受污染湖水的小试试验,并进行对比分析.结果表明:该种针对垂直流人工湿地典型基质的MgFe-LDHs覆膜改性方式可行;改性后的3种基质对CODCr、氨氮、总磷的净化效果均有不同程度的提高;其中,无烟煤基质的覆膜改性性能最优,改性后的无烟煤基质对CODCr、氨氮、总磷的平均去除率分别超过了80%、60%和90%.

Purification effect of vertical flow constructed wetlands using modified substrates coated by MgFe-LDHs

Three kinds of commonly vertical flow constructed wetlands substrates, such as biological ceramsite, anthracite and zeolite, were selected. After the MgCl2 and FeCl3with the metal molar ratio (M2+: M3+) of 2:1were co-precipitated in alkaline conditions to synthesize MgFe-LDHs, the synthesized MgFe-LDHs were in-situ coated on the surface of three kinds of substrates. The simulated substrates test columns were constructed to treat the contaminated lake water using formerly substrates before and after modification. The method of synthesized LDHs being in-situ coated on substrates of vertical flow constructed wetland was feasible. After the modification, the purification effects of CODCr, ammonia nitrogen and total phosphorus were improved by various degrees. Among them, the modified anthracite had optimal performance with average removal efficiencies of CODCr, ammonia nitrogen and total phosphorus more than 80%, 60% and 90%, respectively.