Selective removal of phenolic contaminants for carbon recycling by activated persulfate based on oxidative polymerization mechanism

Abstract

A novel approach for selective removal of phenolic contaminants and polyphenols recycling based on oxidative polymerization is explored, which is significantly different from conventional degradation processes. Plenty of bridging OH− and lattice oxygen are bound on CuO@CuCeyO1+2y+x/2-IE due to strong coordination between Ce and O, which induced formation of Cu(III) with high redox potential. Cu(III) could not only form outer-sphere complexation with peroxymonosulfate (PMS) for enhancement of O2•– production involving series of chain reactions, but also promote O2•– conversion to singlet oxygen (1O2). Owing to electrophilicity, 1O2 preferentially attacked the phenolic hydroxyl group with the production of phenoxeniums ions, and phenoxide ions could immediately couple with negatively charged hydroxyl groups of other bisphenol A (BPA) molecular so as to make polymer chains get a sustained growth over CuO@CuCeyO1+2y+x/2-IE. Thus, CuO@CuCeyO1+2y+x/2-IE can selectively remove phenolic contaminants from water with low oxidant consumption, and simultaneously recycle more than 80 % of polyphenols. In summary, the present work demonstrated the predominant role and mechanism of 1O2 in triggering the oxidative polymerization of BPA, which contributed to construction of cost-efficient catalytic system for phenolic contaminants conversion into polyphenols.