复合生物絮凝剂CBF-1的絮凝作用机理研究

采取PAC+絮凝剂的复配方式开展高岭土悬浊液烧杯实验,考察了复合生物絮凝剂CBF-1、CBF-1溶解物及微生物絮凝剂MBF8的絮凝特性,并借助iPDA仪分析和扫描电镜、光学显微镜观察等手段,比较分析了絮凝过程及絮体特性的差异.结果表明,各复配絮凝的浊度去除效果排序为CBF-1＞ CBF-1溶解物＞MBF8,CBF-1投加量1 mg·L-1时,浊度去除率可达到97.5％；絮体强度排序为CBF-1＞ CBF-1溶解物＞MBF8,絮体恢复因子排序为MBF8＞CBF-1溶解物＞CBF-1,絮体大小排序为CBF-1＞ CBF-1溶解物＞MBF8.单独投加PAC或投加PAC+MBF8的情况下,形成的絮体形态相对规整、密实；投加PAC+ CBF-1溶解物或投加PAC+ CBF-1形成的絮体则相对无序、疏松,CBF-1作用下絮体大、沉降快.CBF-1中高电荷MBF8组分及大分子羧甲基纤维素、羧甲基多聚糖等组分具有强的电荷中和与桥联协同增效作用；CBF-1还含有纤维素、木质素等大分子量且带多种官能团的不溶性组分,在桥联和吸附过程中也起着重要作用.

Flocculation mechanism of compound bioflocculant CBF-1

The flocculation characteristics of CBF-1, CBF-1 solute and MBF8 were studied by coagulation experiment using kaolin suspension in beaker. The flocculation process and properties of the flocs were analyzed by iPDA instrument, scanning electron microscope and optical microscope. The results showed that the CBF-1 performed best in turbidity removal followed by CBF-1 solute and MBF8. 97.5% turbidity removal was achieved at CBF-1 dosage level of 1 mg·L^-1. The flocs formed by CBF-1 had the highest size and strength as compared with the flocs with lowest size and strength formed by MBF8. The recovery ability of flocs formed by MBF8 was stronger than the other two. Dosing PAC or PAC + MBF8 separately resulted in formation of compact flocs, while the flocs was relatively disordered and loose when dosing PAC + CBF-1 solute or PAC + CBF-1. CBF-1 can obviously enlarge the size and improve the settling performance of the flocs. Highly charged MBF8 and macromolecular materials, such as carboxymethyl cellulose, carboxymethyl polysaccharide and insoluble components such as cellulose and lignin contained in CBF-1 had strong charge neutralization and bridging ability which contributed to the better flocculation performance of the CBF-1 than the other two.