Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Xi'an University of Architecture and Technology, Shaanxi 710055, China.
Water Res. 2018 Aug 1;139:291-300. doi: 10.1016/j.watres.2018.04.012. Epub 2018 Apr 5.
The integration of adsorbents with ultrafiltration (UF) membranes is a promising method for alleviating membrane fouling and reducing land use. However, adsorbents typically are only injected into the membrane tank once, resulting in a single dynamic protection layer and low removal efficiency over long-term operation. In addition, the granular adsorbents used can cause membrane surface damage. To overcome these disadvantages, we injected inexpensive and loose aluminum (Al)-based flocs directly into a membrane tank with bottom aeration in the presence of humic acid (HA) or raw water taken from the Miyun Reservoir (Beijing, China). Results showed that the flocs were well suspended in the membrane tank, and multiple dynamic floc protection layers were formed (sandwich-like) on the membrane surface with multiple batch injections. Higher frequency floc injections resulted in better floc utilization efficiency and less severe membrane fouling. With continuous injection, acid solutions demonstrated better performance in removing HA molecules, especially those with small molecular weight, and in alleviating membrane fouling compared with the use of high aeration rate or polyacrylamide injection. This was attributed to the small particle size, large specific surface area, and high zeta potential of the flocs. Additionally, excellent UF membrane performance was exhibited by reservoir water with continuous injection and acid solution. Based on the outstanding UF membrane performance, this innovative integrated filtration with loose Al-based flocs has great application potential for water treatment.
将吸附剂与超滤（UF）膜集成是缓解膜污染和减少土地使用的一种很有前途的方法。然而，吸附剂通常仅被一次性注入到膜池中，从而导致在长期运行过程中仅存在单层动态保护层且去除效率较低。此外，使用的颗粒状吸附剂会对膜表面造成损害。为了克服这些缺点，我们在存在腐殖酸（HA）或来自北京密云水库的原水的情况下，通过底部曝气将廉价且疏松的铝（Al）基絮体直接注入到膜池中。结果表明，絮体在膜池中很好地悬浮，并且在多次批量注入时，在膜表面上形成了多层动态絮体保护层（夹心状）。较高的絮体注入频率导致更好的絮体利用率和较轻的膜污染。随着连续注入，与使用高曝气率或聚丙烯酰胺注入相比，酸溶液在去除 HA 分子（尤其是分子量较小的 HA 分子）和缓解膜污染方面表现出更好的性能。这归因于絮体的粒径小、比表面积大以及较高的 ζ 电位。此外，连续注入酸溶液和水库水时，UF 膜表现出出色的性能。基于 UF 膜的卓越性能，这种具有疏松 Al 基絮体的创新集成过滤技术在水处理方面具有巨大的应用潜力。
