Degradation Of Bisphenol A By Nano-sized Manganese Dioxide Synthesized Using Montmorillonite Clay As Templates

A novel method was developed for synthesizing nano-sized manganese dioxide(MnO2) using montmorillonite clay as template.Exchangeable Mn2+ cations compensating the structural negative charges of montmorillonite were reacted with KMnO4,resulting in the formation of MnO2.Montmorillonite-templated MnO2 was characterized by X-ray diffraction,X-ray photoelecteon spectroscopy etc.The unique structure of montmorillonite clay inhibited the agglomeration of MnO2 resulting in the formation of nanoscale MnO2 particles in the montmorillonite interlayer regions.The clay-templated MnO2 showed superior 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 ?M MnO2) and 21.9 ?M BPA.Humic acid showed significant enhancement on BPA removal under acidic condition,while slight inhibition under alkaline condition.Furthermore,the reasons that humic acid effects on the rate of oxidation were further studied,and a detailed influence mechanism related with montmorillonite was proposed.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.