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Successive removal of E. coli and a mixture of Pb2+ and malachite green from water via magnetic iron oxide/phosphate nanocomposites

Zhang, Fan, Wu, Zhaozhao, Huang, Yuxiong, Keller, Arturo A.
Colloids and surfaces 2019 v.578 pp. 123598
Escherichia coli, disinfection, hot water treatment, iron oxides, lead, magnetic materials, magnetism, malachite green, nanocomposites, phosphates, pollutants, synergism, water treatment
Three magnetic iron oxide/phosphate nanocomposites, Fe₃O₄/Ba₃(PO₄)₂, Fe₃O₄/Sr₅(PO₄)₃(OH), and Fe₃O₄/Sr₅ₓBa₃ₓ(PO₄)₃(OH) (denominated FB, FS, and FSB, respectively) were prepared by one-pot hydrothermal method. They exhibited a removal efficiency of 96%, 86%, and 91% for Escherichia coli (E. coli) of 5 × 10⁸ CFU/mL within 30 min, respectively. After bacterial removal, the recovered nano-composites by a magnet were reused to treat a mixed solution of Pb²⁺ and malachite green (MG). The loaded E. coli on the surface of the nanocomposites is beneficial to the subsequent removal of positively charged Pb²⁺ and MG. On the other hand, the MG in the mixture can contribute substantially to the disinfection of the recovered nanocomposites. These nano-composites are sustainable materials for the successive removal of E. coli and mixed cationic pollutants from water. Removal process by these nano-composites possesses a synergistic effect, leading to more effective water treatment.