Efficient peroxymonosulfate activation and less metallic leaching through kaolin@MnCo2O4 for bisphenol A degradation in environmental remediation

Abstract

In this work, a two-dimensional kaolin supported Mn/Co bimetal oxides (CK-Mn) was synthesized via a simple hydrothermal and calcination process. The resulting ternary hybrid sample exhibited a superior performance for activating peroxymonosulfate (PMS) towards bisphenol A (BPA) degradation, with a pseudo-first-order rate constant of 0.252 min−1, which outperformed other binary hybrids, unitary metal oxides and pristine kaolin. Meanwhile, this CK-Mn sample exhibited excellent stability and reusability after three cycles with extremely low metal ions leaching. The kaolin substrate can not only prevent the agglomeration and leakage of metal species, but it can also enhance the catalytic performance through the synergistic effect between kaolin and MnCo2O4. The CK-Mn/PMS system possessed wide pH application range (3.0 to 9.0) and trifling impacts from the inorganic anions. Multiple radical tests together revealed the dominant reactive oxygen species was sulfate radical (SO4•-) in CK-Mn/PMS system. Furthermore, the CK-Mn/PMS coupled with ultrafiltration membrane system was constructed, and it worked well in the coinstantaneous removing of BPA, turbidity and humic substances from surface water. This study brings forward a facile method for preparing kaolin supported bimetal catalysts for PMS activation and provides new insight into composites catalysis in water environmental remediation process.