Removal of methyl orange from water by Fenton oxidation of magnetic coconut-clothed biochar

Abstract

Water pollution has become a serious environmental problem to date. Advanced oxidation processes (AOP) have been widely applied in water treatments. However, the traditional Fenton reaction based on the Fe²⁺–H₂O₂ system has obvious drawbacks, limiting further practical applications. In this work, an Fe₃O₄ and nano-clothed biochar (Fe₃O₄/CBc) composite was prepared through a precipitation method and used for the degradation of methyl orange (MO) in water. The Fe₃O₄/CBc composite was characterized by FTIR, BET, SEM, TEM, XRD, and VSM. In addition, the adsorption/catalytic oxidation of MO were also tested. Specifically, Fe₃O₄/CBc had a rough surface, abundant porous structure, high surface area of 835.82 m² g⁻¹, and obvious magnetization. The catalyst showed rather high performance towards MO removal. The optimal conditions for MO removal were as follows: the dosage of hydrogen peroxide was 16 mmol L⁻¹, pH = 3, the temperature was 35 °C, and the addition amount of adsorbent was 10 mg. Under optimal conditions, the MO removal rate can be higher than 99%. The synergistic effect between catalytic degradation and adsorption in removing MO was also observed. Besides high performance in removing MO, Fe₃O₄/CBc also exhibited high stability, easy magnetic separation, and great reusability, as well as the potential to be developed as a new heterogeneous Fenton catalyst.