Influences of Surface Coating, UV Irradiation and Magnetic Field on the Algae Removal Using Magnetite Nanoparticles

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• 作者：Shijian Ge ; Michael Agbakpe ; Zhiyi Wu ; Liyuan Kuang ; Wen Zhang ; Xianqin Wang
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：January 20, 2015
• 年：2015
• 卷：49
• 期：2
• 页码：1190-1196
• 全文大小：395K
• ISSN：1520-5851

文摘

Magnetophoretic separation is a promising and sustainable technology for rapid algal separation or removal from water. This work demonstrated the application of magnetic magnetite nanoparticles (MNPs) coated with a cationic polymer, polyethylenimine (PEI), toward the separation of Scenedesmus dimorphus from the medium broth. The influences of surface coating, UV irradiation, and magnetic field on the magnetophoretic separation were systematically examined. After PEI coating, zeta potential of MNPs shifted from 鈭?.9 卤 2.0 to +39.0 卤 3.1 mV at a pH of 7.0, which improved MNPs-algae interaction and helped reduce the dose demand of MNPs (e.g., from 0.2 to 0.1 g路g^鈥? while the harvesting efficiency (HE) of over 80% remained unchanged). The extended Derjaguin鈥揕andau鈥揤erwey鈥揙verbeek theory predicted a strong attractive force between PEI-coated MNPs and algae, which supported the improved algal harvesting. Moreover, the HE was greater under the UV₃₆₅ irradiation than that under the UV₂₅₄, and increased with the irradiation intensity. Continuous application of the external magnetic field at high strength remarkably improved the algal harvesting. Finally, the reuse of MNPs for multiple cycles of algal harvesting was studied, which aimed at increasing the sustainability and lowering the cost.