Complete and rapid degradation of glyphosate with Fe3Ce1Ox catalyst for peroxymonosulfate activation at room temperature

Abstract

Glyphosate, a common broad-spectrum herbicide, is a serious environmental pollutant that causes a significant threat to humans. Hence, there is a pressing task to remove glyphosate from the environment. Here, we report an excellent Fe3Ce1Ox catalyst synthesized via the one-step co-precipitation method for activating peroxymonosulfate (PMS) to degrade glyphosate at 25 °C. As a result, glyphosate is completely degraded with a high degradation rate of 400 mg L−1·h−1, and the TOC and TN removals are 85.6% and 80.8%, respectively. As proven by systematic characterizations, the Fe–Ce synergistic effect plays a significant role in promoting PMS activation. The main reactive oxygen species for glyphosate oxidation are surface-bound SO4−· and ·OH, produced by activating PMS by electron transfer between Fe2+/Fe3+ and Ce3+/Ce4+ of Fe3Ce1Ox. In light of the products determined, the possible degradation process of glyphosate is also speculated: C–N and C–P bonds of glyphosate molecules are attacked to form aminomethylphosphonic acid (AMPA) and orthophosphate (PO43−) by surface-bound SO4−· and ·OH that continuously mineralize and dephosphorylate AMPA to generate small molecules and inorganic ions, such as H2O and PO43−. The results of this work suggest that Fe3Ce1Ox/PMS could provide a potential candidate for efficiently removing organic compounds containing nitrogen or phosphorus from wastewater.