Efficient removal of acetochlor pesticide from water using magnetic activated carbon: Adsorption performance, mechanism, and regeneration exploration.

In this study, MnFe2O4 supported activated carbon magnetic adsorbent (MnFe2O4@AC) was successfully prepared by a simple one-pot solvothermal method and used for the adsorption and removal of acetochlor from aqueous media. Results showed that MnFe2O4@AC with a MnFe2O4/AC mass ratio of 1:2 was characterized by good magnetism and high acetochlor adsorption capacity over a wide ranging pH, ionic strength, and humic acid concentration in an aqueous solution. Acetochlor was adsorbed on MnFe2O4@AC mainly by hydrogen bonding, π-π interactions, and pore-filling via film, intraparticle, and pore diffusion steps. Adsorption reaction generally approached an equilibrium after 10 h, with the adsorption capacity being ca. 226 mg g-1 for 0.2 g L-1 adsorbent at 25 °C. Adsorbate (acetochlor) degradation and adsorbent regeneration were simultaneously achieved through heat-activated peroxymonosulfate (PMS) oxidation catalyzed by MnFe2O4 on the AC surface with >90% degradation efficiency at ≥9.6 mM PMS concentration at 70 °C within 12 h. However, the adsorption capacity of the regenerated adsorbent decreased by 50% of its original capacity. This needs to be addressed in future studies. MnFe2O4@AC adsorbent has the advantages of high adsorption capacity, good magnetism, and catalyzation, which are promising for adsorption, separation, and degradation for the effective removal and treatment of acetochlor as well as other organic contaminants in different types of waters.