Removal of bisphenol A via a hybrid process combining oxidation on β-MnO2 nanowires with microfiltration

A novel hybrid process combining beta-MnO2 nanowires oxidation and microfiltration was adopted to remove bisphenol A (BPA), an endocrine disrupting chemical (EDC) in the aquatic environment. The beta-MnO2 nanowires synthesized via a facile hydrothermal method were characterized by X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscope, and nitrogen sorption. It was demonstrated that beta-MnO2 nanowires can degrade BPA effectively. Investigation on operation parameters indicated that oxidation of BPA using beta-MnO2 nanowires was evidently dependent on pH, while humic acid and coexisting metal ions such as Ca2+, Mg2+, and Mn2+ induced suppressive effects. After oxidation, a crossflow microfiltration process was conducted to efficiently separate and recover the beta-MnO2 nanowires from treated water. Membrane fouling study showed that the as-synthesized beta-MnO2 nanowires possess excellent mechanical stability and was able to retain the 1D structure with high aspect ratios after reaction, thus significantly reducing membrane pore blocking in the microfiltration process. (C) 2011 Elsevier B.V. All rights reserved.