Reactive oxygen species induced by plant essential oil for effective degradation of p-phenylenediamine

p-Phenylenediamine (PPD) is an aromatic amine commonly used in hair dyes which has high toxicity including carcinogenicity and mutagenicity. It is crucial to eliminate its danger to public health and environmental quality. Advanced oxidation processes (AOPs) are promising methods to degrade contaminants using reactive oxygen species (ROS) but are often complex and toxic. Herein, a simple, green and environmentally friendly strategy is proposed to degrade pollutants using biochar loaded self-emulsifying orange peel essential oil (BC/SE-OPEO) to efficiently adsorb and degrade PPD. After the optimal experiments, the results show that the PPD removal efficiency of 50 mg BC/SE-OPEO reaches around 98% after 110 min at 40 °C. In addition, BC/SE-OPEO was successfully applied to the removal of PPD from actual hair dye sewage and from dyed hair. Mechanistic investigations proves that ROS plays a vital role in the degradation of PPD which is eventually degraded to carbon dioxide and water.