MgFeAl-layered double oxides supported on hollow carbon microsphere composited with carbonitride for peroxymonosulfate activation to efficiently decontaminate organic pollutants under high salinity conditions

Abstract

Layered double oxides (LDOs)-based materials have received widespread interests in advanced oxidation processes (AOPs) due to their adjustable layered structure and superior stability, while the evolution of LDOs as high-efficiency catalysts is hindered by their easy aggregation and weak conductivity. Here, we report a novel strategy to simultaneously overcome the agglomeration and poor conductivity of LDOs via calcining the mixture of polystyrene microsphere supported MgFeAl-LDH and urea, in which the introduction of hollow structure and nitrogen-doped carbon composition can not only significantly increase the specific surface area to expose more active sites, but also remarkably improve conductivity to accelerate electron transfer, giving rise to the outstanding performance of the final catalyst (HC@LDH-CN) in peroxymonosulfate (PMS) activation. Systematic characterizations and experiments further confirm that O2•− radicals play the dominant role in HC@LDO-CN/PMS system, which can altogether remove the model pollutant bisphenol A (BPA) in 10 min with kobs to be 0.403 min−1. Particularly, the HC@LDO-CN still maintains extraordinary catalytic activity for BPA degradation in an extremely high-salt wastewater (100 mM). Our strategy thereby provides an innovative notion to synthesize efficient PMS-based catalysts for organic pollutant degradation in high saline water.