Characterization and influence of floc under different coagulation systems on ultrafiltration membrane fouling
Characterization and influence of floc under different coagulation systems on ultrafiltration membrane fouling
复制标题
不同混凝体系下絮体的表征及对超滤膜污染的影响
DOI：
10.1016/j.chemosphere.2019.124659
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发表时间：
2020-01-01
期刊：
影响因子：
8.8
通讯作者：
Yue, Qinyan
中科院分区：
文献类型：
--
作者：
Shen, Xue;Gao, Baoyu;Yue, Qinyan
在这项研究中开发的混合系统，包括不同的混凝系统和超滤（UF）。研究了不同混凝体系中形成的絮体的性质及其对超滤膜污染控制的影响。3种混凝系统作为超滤的预处理，在一定的天然有机物浓度范围内，均能有效提高膜通量，降低膜阻力。当NOM初始浓度较高时，聚合氯化铝（PAC）对NOM的去除和污染控制效果受到严重限制。对于PAC-聚二甲基二烯丙基氯化铵（PAC-PolyDMDAAC）混凝体系，NOM初始浓度对去除NOM和减轻膜污染的限制略有减弱，表明复合絮凝剂PAC-PolyDMDAAC通过电中和和吸附架桥的共同作用产生了较大的絮体。在PAC + PolyDMDAAC复合混凝体系中，无论是在低NOM初始浓度还是在高NOM初始浓度条件下，吸附架桥效应、吹扫效应和电中和效应的共同作用均为混凝机理。虽然PAC + PolyDMDAAC复合混凝体系形成的絮体与PAC和PAC-PolyDMDAAC复合混凝体系形成的絮体相比，恢复能力较差，但吸附架桥和吹扫形成的絮体粒径较大，抗剪切力能力较强，导致PAC + PolyDMDAAC复合混凝体系形成多孔蓬松结构的滤饼层，膜孔堵塞较少。研究结果表明，采用PAC混凝和PolyDMDAAC絮凝相结合的双混凝系统作为超滤工艺的预处理，可以改善絮体的特性和滤饼层的结构，从而提高NOM的去除率，控制膜污染。(C)2019爱思唯尔有限公司版权所有。
A hybrid system was developed in this study consisting of different coagulation systems and ultrafiltration (UF). Property and effect of flocs formed in different coagulation systems on ultrafiltration membrane fouling control were investigated. All three coagulation systems, as pretreatment of UF, were effective in improving membrane flux and reducing membrane resistance within an appropriate range of natural organic matters (NOM) concentration. At high initial NOM concentration, the performance of polyaluminum chloride (PAC) on NOM removal and fouling control was severely limited. For PAC-poly dimethyl diallyl ammonium chloride (PAC-PolyDMDAAC) coagulation system, the limitation of initial NOM concentration on removing NOM and alleviating membrane fouling was slightly weakened, indicating composite flocculant PAC-PolyDMDAAC produced larger flocs through combined action of charge neutralization and adsorption bridging. In PAC + PolyDMDAAC dual coagulation system, the combined action of adsorption-bridging effect, sweeping effect, and charge neutralization were the mechanisms under both low and high initial NOM concentration. Although the flocs formed in PAC + PolyDMDAAC dual coagulation system had poor recovery ability compared with those formed in PAC and PAC-PolyDMDAAC coagulation system, flocs formed through adsorption-bridging and sweeping had large size and higher ability to resist shear force, resulting in the formation of cake layer with porous and fluffy structure and less blockage in membrane pore in PAC + PolyDMDAAC dual coagulation system. These results demonstrated that dual coagulation system combined PAC coagulation and PolyDMDAAC flocculation as a pretreatment of UF process can improve the characteristics of flocs and structure of cake layer for improving NOM removal and controlling membrane fouling. (C) 2019 Elsevier Ltd. All rights reserved.