Biomass-based porous materials encapsulating Iron phosphide nanoparticles for enhanced contaminant removal via peroxymonosulfate activation

The highly efficient biochar-based catalysts from agricultural biomass wastes receive tremendous interest in the wastewater restoration field because of lower cost and environmental friendliness. Herein, the abundant agricultural waste loofah sponge is used as the precursor to prepare eco-friendly carbonized loofah sponge encapsulating Iron Phosphide nanoparticles (CLS-IP) by a facile pyrolysis strategy. The as-synthesized CLS-IP not only exhibited excellent catalytic activity for Acid Red 1 removal via activating peroxymonosulfate (PMS), which achieved 94.4% removal in 24 min, but also removed other common pollutants including phenolic compounds, sulfonamides, and dyes. Besides, the iron ions leaching (0.03–0.19 ppm) was obviously lower than 2.00 ppm according to European standard even after reuse. Surprisingly, the used CLS-IP catalyst could be effectively regenerated after the oxalic acid immersion treatment. In addition, the CLS-IP still exhibited remarkable catalytic activity even after five months of storage. Four types of reactive oxygen species (ROS) including hydroxyl radical (•OH), sulfate radical (SO4•−), superoxide radical (O2•−), and singlet oxygen (1O2) were generated during the reaction, and the superoxide radical made a dominant contribution. This work provided an avenue for developing low-cost biochar-based catalysts in environmental remediation.