Insights into the glyphosate removal efficiency by using magnetic powder activated carbon composite

Abstract

In this study, co-precipitation was used to prepare Fe3O4 magnetic powder activated carbon (PAC) (Fe3O4-PAC) and MnFe2O4 magnetic PAC (MnFe2O4-PAC) for the in-depth treatment of glyphosate pesticide wastewater. Magnetic adsorbent characterization results indicate that MnFe2O4 was successfully loaded on the activated carbon powder. Adsorption experiment results show that the maximum adsorption capacity of MnFe2O4-PAC for glyphosate is two to three times that of the original PAC. The adsorption of glyphosate by using magnetic PAC conforms to the Langmuir adsorption isotherm, and the adsorption kinetics is consistent with the quasi-second adsorption kinetic model. The adsorption capacity of Fe3O4-PAC and MnFe2O4-PAC showed the same trend effect with the change in pH, temperature, and adsorbent dosage. The adsorption capacity of Fe3O4-PAC and MnFe2O4-PAC for glyphosate decreased with the increase in pH and magnetic PAC and rises with temperature. Regeneration experiment results showed that the order of the regeneration method of MnFe2O4-PAC is: microwave combined Fenton reagent regeneration > wet microwave regeneration > microwave combined hydrogen peroxide regeneration. MnFe2O4-PAC after regeneration still exhibited good magnetic properties and adsorption capacity.