海水微絮凝预处理对超滤膜通量的影响

Influence of seawater micro-flocculation pretreatment on ultrafiltration membrane flux

以聚合氯化铁为絮凝剂,研究了海水微絮凝预处理过程的絮凝特征以及对超滤膜通量的影响。考察了微絮凝对海水中有机物的去除作用,并采用体系稳定动力学参数、絮凝指数评价不同絮凝剂投加量在海水中的絮凝效果,探讨了微絮凝对超滤膜污染的改善作用。实验结果表明,微絮凝预处理能强化超滤膜对海水UV_(254)的去除效果,与超滤相比提高了27.5%,可有效去除海水中的蛋白类有机物。超滤膜直接过滤海水可造成膜通量严重下降,采用微絮凝作为预处理能有效减缓超滤膜污染,且减缓效果与絮凝剂的投加量密切相关,当PFC的投加量为40 mg·L^(-1)时,膜比通量J/J_0值大于0.9。

Polyferric chloride was used as flocculent for seawater micro-flocculation. The floc characteristic and its impacts on permeate flux of ultrafiltration membrane were investigated. The removal efficiencies of organic matter in different flocculant dosage were studied by monitoring the stability kinetic parameter and flocculation index parameter, and the effects of micro-flocculation on mitigating membrane fouling were also determined. The experimental results demonstrated that the removal rate of UV254 increased by 27.5% when micro-flocculation was adopted before ultrafiltration. The micro-flocculation could enhance removal of the protein-like organic matter of seawater. The membrane flux declined severely during seawater ultrafiltration process, which could be effectively alleviated by using micro-flocculation. The mitigating effects were closely related to the flocculent dosage. When the dosage of polyferric chloride was 40 mg·L-1, membrane specific flux J/J0 was greater than 0.9.