Generating High‐valent Iron‐oxo ≡Fe<sup>IV</sup>=O Complexes in Neutral Microenvironments through Peroxymonosulfate Activation by Zn−Fe Layered Double Hydroxides
Yan Bao, Cheng Lian, Kai Huang, Haoran Yu, Wenyuan Liu, Jinlong Zhang, Mingyang Xing
Abstract
Abstract The universal limit on the pH conditions is disturbing peroxymonosulfate (PMS)‐triggered high‐valent iron‐oxo systems in environmental applications. Here, we propose for the first time the construction of a neutral microenvironment on the surface of Zn−Fe layered double hydroxide (ZnFe‐LDH) by using the amphoteric properties of zinc hydroxide, which continuously generates ≡Fe IV =O over a wide pH range of 3.0–11.0 in activating PMS. The ≡Zn(OH) 2 moiety offers a neutral microenvironment at the phase interface, which mitigates the self‐decomposition of ≡Fe IV =O by protons and the hydrolysis reaction of iron by hydroxyl groups, which is supported by the Mossbauer spectra, density functional theory calculations and designed experiments. Consequently, ZnFe‐LDH/PMS can satisfy the stability in long‐term experiments, selectivity under conditions with high salinity or natural organic matter and efficient treatment of actual wastewater.