Using adsorbent mixtures to mitigate membrane fouling and remove NOM with microgranular adsorptive filtration
Using adsorbent mixtures to mitigate membrane fouling and remove NOM with microgranular adsorptive filtration
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DOI：
10.1016/j.memsci.2018.12.009
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发表时间：
2019-03-01
影响因子：
9.5
通讯作者：
Benjamin, Mark M.
中科院分区：
文献类型：
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作者：
Modarresi, Siamak;Benjamin, Mark M.
本研究调查了间歇式和微粒吸附过滤 (mu GAF) 反应器中加热的氧化铝颗粒 (HAOP) 和粉末活性炭 (PAC) 的混合物从水中去除天然有机物 (NOM) 及其对膜污染的影响。在间歇式反应器中，增加吸附剂混合物中 HAOP 的比例会导致膜污染的稳定增加。然而，当水在 mu GAF 反应器中使用相同的吸附剂混合物进行预处理时，这种趋势发生了逆转。相反的趋势追踪了 NOM 中生物聚合物部分的去除趋势。结果与以下假设一致：污垢主要是由于膜表面上形成浓缩的富含生物聚合物的凝胶层而引起的。根据这一假设，当进料在间歇式反应器中进行预处理时，每种吸附剂上都会收集到一些污垢，其中 PAC 收集的污垢比 HAOP 收集的更多，但积累的材料不会凝结成凝胶。然而，当使用mu GAF反应器代替间歇式反应器进行预处理时，吸附剂颗粒的紧密堆积促进了凝胶的形成，总体上导致NOM去除率增加，特别是污染物去除率增加。随着 mu GAF 吸附剂层中 HAOP 用量的增加和 PAC 用量的减少，结垢减轻程度增加，这一事实表明 HAOP 在促进凝胶层形成方面比 PAC 更有效。概括这一结果，看来在 mu GAF 反应器中通过吸附剂混合物进行预处理可能比在充分混合的反应器中应用单一吸附剂的传统方法具有显着的优势。
This study investigated the removal of natural organic matter (NOM) from water, and its effect on membrane fouling, by mixtures of heated aluminum oxide particles (HAOPs) and powdered activated carbon (PAC) in both batch and microgranular adsorptive filtration (mu GAF) reactors. In batch reactors, increasing the portion of HAOPs in the adsorbent mixture led to a steady increase in membrane fouling. However, this trend was reversed when the water was pretreated with the same adsorbent mixtures in mu GAF reactors. The opposing trends tracked the trend for removal of the biopolymer fraction of the NOM.The results are consistent with a hypothesis that the fouling was caused primarily by formation of a condensed, biopolymer-rich gel layer on the membrane surface. According to this hypothesis, when the feed was pretreated in batch reactors, some foulants were collected on each adsorbent, with PAC collecting more foulant than HAOPs did, but the accumulated material did not condense into a gel. However, when mu GAF reactors were used instead of batch reactors for pretreatment, the tight packing of the adsorbent particles promoted the formation of a gel, leading to increased NOM removal in general and increased foulant removal in particular. The fact that fouling mitigation increased with increasing amounts of HAOPs and decreasing amounts of PAC in the mu GAF adsorbent layer suggests that HAOPs are much more effective than PAC at promoting formation of the gel layer. Generalizing this result, it appears that pretreatment by mixtures of adsorbents in mu GAF reactors could have significant advantages over conventional approaches in which a single adsorbent is applied in a well-mixed reactor.