铁盐与铝盐对腈纶废水生化出水混凝特性的对比

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pH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pH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。

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

This study compares the COD removal efficiency between Al2(SO4)3 and Fe2(SO4)3 towards biological effluents of acrylic fiber wastewater treatment plant at different doses and pH.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 pH for COD removal is observed to be in neutral pH ranges.Al2(SO4)3 shows higher COD removal than Fe2(SO4)3 at 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)3 doses and the maximum removal is as high as 43.7% at 120 mg/L.EEM analysis indicates that Fe2(SO4)3 is more effective in removing a greater variety of organic pollutants compared with Al2(SO4)3.HPSEC analysis indicates that Fe2(SO4)3 shows higher removal efficiency towards high molecular weight organics whereas Al2(SO4)3 exhibits 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.