Coactivation of Hydrogen Peroxide Using Pyrogenic Carbon and Magnetite for Sustainable Oxidation of Organic Pollutants

Pyrogenic carbon and magnetite (Fe₃O₄) were mixed together for the activation of hydrogen peroxide (H₂O₂), aiming to enhance the oxidation of refractory pollutants in a sustainable way. The experimental results indicated that the straw-derived carbon obtained by pyrolysis at 500–800 °C was efficient on coactivation of H₂O₂, and the most efficient one was that prepared at 700 °C (C700) featured with abundant defects. Specifically, the reaction rate constant (k_obs) for removal of an antibiotic ciprofloxacin in the coactivation system (C700/Fe₃O₄/H₂O₂) is 12.5 times that in the magnetite-catalyzed system (Fe₃O₄/H₂O₂). The faster pollutant oxidation is attributed to the sustainable production of ^•OH in the coactivation process, in which the carbon facilitated decomposition of H₂O₂ and regeneration of Fe(II). Besides the enhanced H₂O₂ utilization in the coactivation process, the leaching of iron was controlled within the concentration limit in drinking water (0.3 mg·L^–1) set by the World Health Organization.