Waste control by waste: phosphogypsum-derived copper-hydroxyapatite catalysts for alkaline mineralization of glyphosate

Phosphogypsum (PG) disposal and pollution pose dual environmental challenges in phosphorus industries. This study pioneers a one-step synthesis of copper-modified hydroxyapatite (Cu/PGHAP) directly from PG waste, enabling efficient Glyphosate ( Phosphonomethylglycine, PMG) degradation via Fenton-like catalysis. Cu/PGHAP was synthesized by co-precipitation under optimized conditions (20 % Cu/Ca, 333.15 K, 16 h aging). Catalytic performance was evaluated by PMG removal kinetics, with mechanistic insights from SEM, XRD, FTIR, BET, and EPR. The results showed that Cu/PGHAP possesses a hierarchical mesoporous structure (specific surface area of 57.16 m 2 /g) and lattice-embedded Cu 2+ sites. Under optimal conditions (6 g/L catalyst, 5 mM H 2 O 2 , 50 mg/L PMG, pH 11), 100 % PMG removal was achieved within 60 min. Alkaline processing enhances stability, maintaining 99.86 % reusability after 10 cycles, with extremely low copper ion leaching. Radical capture experiments confirmed the 1 O 2 driven degradation mechanism. This work establishes a “waste control by waste” strategy for simultaneous PG valorization and PMG detoxification, advancing circular economy in chemical industries.