| 藻形态及混凝剂组成对混凝-超滤过程的影响 |
| 摘要点击 2082 全文点击 843 投稿时间：2017-01-16 修订日期：2017-03-19 |
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| 中文关键词 藻形态 铝形态 混凝-超滤 静电簇 膜污染 |
| 英文关键词 algal morphology Al species distribution coagulation-ultrafiltration electrostatic patch effects membrane fouling |
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| 中文摘要 |
| 为了保证藻类暴发阶段优质的饮用水供应，提高藻类的去除率，缓解藻类对水处理过程的影响，本研究以铜绿微囊藻（蓝藻）、小球藻（绿藻）和小环藻（硅藻）这3种不同形态藻细胞为研究对象，使用了3种具有不同铝形态分布的混凝剂 [Al2（SO4）3（AS）、Al13、Al30] 进行混凝-超滤实验. 在分离胞外有机物（EOM）的情况下，考察混凝过程中絮体的特性（粒径，强度因子，恢复因子）以及不同条件下形成的絮体对膜通量的影响. 结果表明Al13与Al30的混凝作用以静电簇作用为主导，AS主要是以电中和作用为主导. 对于铜绿微囊藻与小球藻体系，由于藻颗粒表面存在一定的凹陷，当Al13与Al30做混凝剂时，在投加量较低的情况下，吸附在颗粒表面凹陷处的混凝剂"失活"，其他部位由于仍带有一定的负电荷而造成絮体形成不明显，而AS做混凝剂时，混凝机制主要是电中和作用，可以明显降低颗粒之间的排斥力，在较低投加量下即可形成絮体. 对于小环藻体系，由于其藻细胞呈现光滑的表面，Al13与Al30可有效发挥其静电簇作用机制，絮体在较低投加量下即可有效形成. 膜通量与絮体粒径有明显的相关性，絮体粒径越大，超滤过程中形成的沉积层越疏松，膜比通量越大. |
| 英文摘要 |
| In order to ensure drinking water quality, three different Al-based coagulants [Al2(SO4)3(AS), Al13, Al30] were used to treat water laden with different algae [Microcystis aeruginosa(cyanobacteria), Chlorella(green algae), Cyclotella (diatoms)]. Floc size, strength factor, and recovery factor under different conditions were measured to investigate the mechanisms in the coagulation-ultrafiltration process. The results indicated that the main mechanism in the coagulation process using Al13 or Al30 as coagulants was electrostatic patching and the main mechanism using AS was charge neutralization. In the Microcystis aeruginosa and Chlorella systems, when Al13 and Al30 were used as coagulants at low dosage, the coagulants that were adsorbed on the side (which existed on the surfaces of Microcystis aeruginosa and Chlorella cells) would lose their ability to aggregate the algal cells. When AS was used as coagulant, the electric double layer was effectively compressed. The repulsive force between algal particles decreased, and the flocs formed easily. In the Cyclotella system, Al13 and Al30coagulants effectively formed the flocs through electrostatic patch effects. There was a significant correlation between membrane flux and floc size, and the larger flocs formed a looser cake layer on the membrane surface. |
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