蒙脱石矿物材料絮凝剂的制备、絮凝效果及机理研究

为了降低絮凝剂毒性、提高絮体的分离效果,以无机矿物材料蒙脱石(MTS)为原料,通过酸改性,制备蒙脱石絮凝剂(MTSF),对比聚合氯化铝(PAC)絮凝剂来处理模拟废水。实验结果表明,MTS没有絮凝作用,但经过酸改性后的MTSF具有很好的絮凝效果,最大浊度去除率为96.73%,在絮体沉降速度及体积上,MTSF远优于PAC。MTSF絮凝机理是吸附-电中和,絮凝过程是固体颗粒和可溶性盐两者的协同作用,MTSF显示出较好的沉降性能和压缩性能,絮体达到沉降平衡后,其体积不足PAC的三分之一。MTSF与PAC絮凝剂复合使用,可有效地减少絮体体积,提高絮体沉降性能。总之,MTSF具有与PAC相同的絮凝效果,但是絮体的沉淀压缩性能远优于PAC,是一种综合性能优越的絮凝剂。

Study on preparation, flocculation effect, and mechanism of montmorillonite mineral material flocculant

Montmorillonite flocculant(MTSF) was prepared with acid-modified inorganic mineral montmorillonite(MTS) and used to treat simulated wastewater, to which it was compared with the traditional flocculant polyaluminum chloride(PAC), in terms of settling effect and biotoxicity of the floc. The results showed that MTS(without acid modification) had no obvious flocculation performance, whereas MTSF(with acid modification) had good flocculation performance. Specifically, the maximum turbidity removal efficiency of MTSF reached 96.73% when compared to that of PAC. However, MTSF performed much better than PAC regarding settling volume and settling velocity of the floc. The MTSF flocculation mechanism was attributed to the joint function of adsorption and electrification, caused by a synergistic effect between solid particles and soluble salts of the MTSF, which gave rise to its better floc settling performance and compressive properties. After equilibrium of the flocculation settling process, the floc volume of MTSF was less than one third that of PAC. Overall, MTSF had similar flocculation effect to that of PAC in terms of turbidity removal efficiency, whereas its settling and compressive properties were much better than those of PAC. The novel flocculant MTSF was assumed to have superior comprehensive flocculation performance compared with traditional flocculants, such as PAC.