铁盐与铝盐对腈纶废水生化出水混凝特性的对比

Coagulation behaviors of iron and aluminum salts towards biological effluents of acrylic fiber wastewater treatment plant

针对腈纶废水生化单元出水,对比研究了Al2(SO4)3和Fe2(SO4)3在不同絮凝剂投量和p H时的混凝处理效果,并利用紫外-可见分光光度法(UV-Vis)、三维荧光光谱(EEM)、凝胶渗透色谱(HPSEC)等对混凝特性进行了初步探讨。研究显示,2种混凝剂在投量为63.5 mg/L时可获得30%以上的COD去除率,且最佳p H为中性附近。当投量小于32 mg/L时,Al2(SO4)3较Fe2(SO4)3具有更高的COD去除率,进一步增大混凝剂的投量很难提高Al2(SO4)3对COD的去除率,而Fe2(SO4)3则在有限范围内能持续提高COD去除率。EEM光谱分析显示,与Al2(SO4)3相比,Fe2(SO4)3对有机物具有更广的处理范围和更好的去除效果。HPSEC分析表明,Fe2(SO4)3相对于Al2(SO4)3在去除重均分子量为2 776、1 856和1 325 Da的有机物组分方面具有优势。铁盐或铝盐混凝是深度净化腈纶废水生化单元出水的可行方案之一。

This study compares the COD removal efficiency between Al2( SO4)3and Fe2( SO4)3towards biological effluents of acrylic fiber wastewater treatment plant at different doses and p H. Their behaviors in the coagulation process were further investigated by UV-Vis,EEM and HPSEC. Results indicate that these two coagulants at dose of 63. 5 mg / L can achieve COD removal of above 30%,and the optimum p H for COD removal is observed to be in neutral p H ranges. Al2( SO4)3shows higher COD removal than Fe2( SO4)3at relatively low doses of below 32. 1 mg / L,and further elevated doses can hardly improve COD removal. COD removal increases steadily with elevated Fe2( SO4)3doses and the maximum removal is as high as 43. 7% at 120 mg / L. EEM analysis indicates that Fe2( SO4)3is more effective in removing a greater variety of organic pollutants compared with Al2( SO4)3. HPSEC analysis indicates that Fe2( SO4)3shows higher removal efficiency towards high molecular weight organics whereas Al2( SO4)3exhibits priority in removing low-molecular weight organics. Coagulation by iron and aluminum salts is feasible to remove the organics in the biological effluents of acrylic fiber wastewater.