Degradation of bisphenol A by nano-sized manganese dioxide synthesized using montmorillonite as templates

A new method was developed to synthesize nanoscale manganese dioxide (MnO2) using natural montmorillonite as the template. When the exchangeable Mn2+ cations reacted with KMnO4, the unique structure of montmorillonite effectively prevented the agglomeration of MnO2 resulting in the formation of nano-sized MnO2 particles. The clay mineral-templated MnO2 showed higher reactivity compared to nano-MnO2 prepared by conventional method as indicated by the oxidation of bisphenol A (BPA). Over 90% of BPA could be degraded within 10 min at pH 4.0 containing 250 mg L-1 montmorillonite (109 mu M MnO2) and 21.9 mu M BPA. The presence of humic acid showed significant enhancement on BPA removal under acidic condition, while slight inhibition under alkaline condition. Due to the ubiquitous distribution of montmorillonite in natural environment, montmorillonite templated MnO2 would offer the potential for in situ remediation of many organic contaminants. (C) 2016 Elsevier B.V. All rights reserved.