Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
Chemosphere. 2018 Jun;200:86-92. doi: 10.1016/j.chemosphere.2018.02.114. Epub 2018 Feb 19.
This study investigated membrane fouling in a coagulation/ultrafiltration (C-UF) process by comparing the floc properties and humic acid (HA) removal efficiency of three hydrous Al(III) species (Al, Al, and Al). The results indicated that the coagulation and membrane mechanisms were different for all three Al species because of the differences in floc properties. The HA removal efficiency increased with increasing Al dosage until an equilibrium was reached at the optimal dosage of 6 mg L. In addition, membrane fouling gradually decreased as the Al dosages increased. Regardless of coagulant type, the OH and COOH functional groups of HA reacted with the Al species. Both external and internal membrane fouling were strongly dependent on the porosity of the cake layer and on the size distribution of the floc particulates, respectively. The pore area of the cake layer formed by the Al-coagulated effluent was large because of the strong charge neutralization. Moreover, Al generated large and loose flocs with a porous cake layer that mitigated external fouling. However, the internal fouling with the Al coagulant was significant because the concentration of residual aggregates in the membrane pores was high.
本研究通过比较三种水合三价铝物种（Al、Al 和 Al）的絮体特性和腐殖酸（HA）去除效率，考察了混凝/超滤（C-UF）工艺中的膜污染问题。结果表明，由于絮体特性的不同，三种 Al 物种的混凝和膜分离机制也不同。随着 Al 投加量的增加，HA 的去除效率逐渐提高，在最佳投加量 6mg/L 时达到平衡。此外，随着 Al 投加量的增加，膜污染逐渐减轻。无论混凝剂类型如何，HA 的 OH 和 COOH 官能团均与 Al 物种发生反应。无论是外部还是内部膜污染，均强烈依赖于滤饼层的孔隙率和絮体颗粒的粒径分布。Al 混凝出水形成的滤饼层的孔径较大，因为强电荷中和作用。此外，Al 生成大而疏松的絮体，具有多孔的滤饼层，可减轻外部污染。然而，Al 混凝剂的内部污染很严重，因为膜孔中残留的聚集物浓度很高。
