Efficient activation of peroxymonosulfate and degradation of Orange G in iron phosphide prepared by pickling waste liquor

In this study, the low-cost preparation of iron phosphide by using pickling waste liquor as the initial material was performed through a two-step reaction. The degradation of Orange G was evaluated using iron phosphide coupled with peroxymonosulfate to construct a catalytic system. The removal efficiencies of Orange G and total organic carbon reached 97.4 and 58.4% at 60 min, respectively. Iron phosphide has dual-catalysis centers for the activation of PMS. Multiple free radicals (e.g., SO 4 •− , HO • , SO 5 •− , and O 2 •− ) and singlet oxygen were involved in the pollutant degradation , of which sulfate radicals played the main role. The iron phosphide catalyst exhibited excellent recycling stability, and its catalytic efficiency reached 95% after five cycles. In summary, the Fe 2 P/PMS system—as a Fenton-like catalytic system—has certain advantages, including low cost, high efficiency, sufficient reusability, and good stability, all of which are favorable for its practical application.