Novel porous Mn-Fe nanocubes toward peroxymonosulfate activation via non-radical/radical pathways for emerging contaminants degradation

Abstract

Novel porous Mn-Fe nanocubes (p-MnFe NCs) with abundant oxygen vacancies, which derived from Mn-Fe prussian blue analogue, were fabricated for the first time through annealing at H2 atmosphere. Among the different molar ratios of Mn/Fe, p-Mn1Fe1 NCs possessed abundant oxygen vacancies and exhibited excellent performance for peroxymonosulfate (PMS) activation to effectively degrade bisphenol A (BPA). As a result, 100% BPA (20 mg/L) degradation efficiency can be achieved within 30 min in the p-Mn1Fe1 NCs/PMS system. SO4•−, HO•, O2•− and 1O2 were confirmed as main reactive oxygen species during catalytic reaction. The exposed Mn and Fe sites on the surface of p-Mn1Fe1 NCs were the main active sites for the generation of reactive radicals. For non-radical generation pathway, the generated 1O2 and O2•− mainly originated from the reaction between dissolved oxygen and surface oxygen vacancies, and parts of 1O2 originated from the formation of intermediate O2•−. Radical and non-radical pathways were proposed in the p-Mn1Fe1 NCs/PMS system for insights into the mechanisms of BPA degradation. Finally, the possible degradation pathways were proposed via ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-TOF-Q-MS) analysis.