State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Sci Total Environ. 2018 Aug 1;631-632:560-569. doi: 10.1016/j.scitotenv.2018.03.045. Epub 2018 Mar 16.
This study investigated the pretreatment effect of ferrihydrite (FH) on the removal of dissolved organic matter (DOM) and membrane fouling control in a hybrid adsorption-ultrafiltration (UF) membrane system. Powdered activated carbon (PAC) was chosen for comparative study, and three surrogates, namely, humic acid (HA), sodium alginate (SA) and bovine serum albumin, were applied in feed water to simulate humic substances, polysaccharides and proteins, respectively. In the hybrid adsorption-membrane system, the impacts of adsorbent cake layers on DOM removal and membrane fouling were systematically investigated. The results demonstrated that FH effectively removed both high-molecular-weight (MW) and low-MW HA and SA molecules via ligand exchange and mitigated membrane fouling substantially, regardless of whether FH particles were removed from the feed water before UF. In addition, the large flocs induced by FH and calcium contributed to loose FH layers. In contrast, PAC had almost no capacity to adsorb high-MW DOM molecules due to the microporous structure. And FH was more efficient in removal of DOM and control of membrane fouling than PAC. The different DOM adsorption capacities of FH and PAC lead to different effects on membrane fouling caused by deposition of DOM molecules and cake layers. These results offer guidance for application of hybrid adsorption-membrane filtration systems.
本研究考察了水铁矿（FH）预处理对混合吸附-超滤（UF）膜系统中溶解有机物（DOM）去除和膜污染控制的影响。选择粉末活性炭（PAC）进行对比研究，并在给水中应用三种替代物，即腐殖酸（HA）、海藻酸钠（SA）和牛血清白蛋白，分别模拟腐殖质、多糖和蛋白质。在混合吸附-膜系统中，系统研究了吸附剂饼层对 DOM 去除和膜污染的影响。结果表明，FH 通过配体交换有效地去除了高分子量（MW）和低分子量的 HA 和 SA 分子，并在 UF 之前是否从给水中去除 FH 颗粒，均能显著减轻膜污染。此外，FH 和钙诱导的大絮体促成了松散的 FH 层。相比之下，由于微孔结构，PAC 几乎没有吸附高分子量 DOM 分子的能力。而且，FH 在去除 DOM 和控制膜污染方面比 PAC 更有效。FH 和 PAC 对 DOM 的不同吸附能力导致它们对 DOM 分子沉积和饼层引起的膜污染的影响不同。这些结果为混合吸附-膜过滤系统的应用提供了指导。
