Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, Shandong, PR China.
Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, Shandong, PR China.
Sci Total Environ. 2019 Dec 1;694:133816. doi: 10.1016/j.scitotenv.2019.133816. Epub 2019 Aug 6.
Precoagulation by polyaluminum chloride-poly dimethyl diallyl ammonium chloride (PAC-PDMDAAC) prior to ultrafiltration (UF) was conducted to evaluate the influence of PAC-PDMDAAC on controlling membrane fouling from typical natural organic matter (NOM) mixtures of humic acid (HA), bovine serum albumin (BSA) and sodium alginate (SA). Membrane flux decline and flux recovery after backwashing were investigated to evaluate the membrane fouling. The fouling mechanisms were determined from the floc size, floc structure and membrane resistance. PAC-PDMDAAC effectively alleviated membrane fouling caused by the HA, HA-BSA, HA-SA and HA-BSA-SA mixtures; furthermore, membrane fouling was better mitigated in the HA-SA and HA-BSA-SA mixtures. The untreated HA-SA and HA-BSA-SA mixtures caused much more serious total membrane resistance and fouling due to blocking and adsorption in the membrane pores by particles with sizes similar to those of the pores. The increased membrane flux and decreased irreversible resistance after the PAC-PDMDAAC pretreatment were attributed to the formation of flocs with a large size and small fractal dimension, which mainly formed a cake layer on the membrane surface. However, PAC-PDMDAAC was not particularly effective in reducing the irreversible membrane fouling originating from the HA and HA-BSA mixtures due to the formation of aggregates and pore blocking by microflocs.
聚合氯化铝-聚二甲基二烯丙基氯化铵（PAC-PDMDAAC）预混凝超滤（UF）以评估 PAC-PDMDAAC 对控制典型天然有机物（NOM）混合物腐殖酸（HA）、牛血清白蛋白（BSA）和海藻酸钠（SA）的膜污染的影响。通过测量膜通量下降和反冲洗后的通量恢复来评估膜污染。通过絮体大小、絮体结构和膜阻力来确定污染机制。PAC-PDMDAAC 可有效减轻 HA、HA-BSA、HA-SA 和 HA-BSA-SA 混合物引起的膜污染；此外，在 HA-SA 和 HA-BSA-SA 混合物中，膜污染得到了更好的缓解。未经处理的 HA-SA 和 HA-BSA-SA 混合物由于颗粒大小与膜孔相似而在膜孔中堵塞和吸附，导致总膜阻力和污染更加严重。PAC-PDMDAAC 预处理后膜通量增加和不可逆阻力降低归因于形成了大尺寸和小分形维数的絮体，这些絮体主要在膜表面形成了一层滤饼。然而，由于微絮体的聚集和孔堵塞，PAC-PDMDAAC 对减轻由 HA 和 HA-BSA 混合物引起的不可逆膜污染的效果并不明显。
