Carbon black endorsed CuGd2-xPrxO4 nanocomposites for efficient photocatalytic disintegration of lomefloxacin hydrochloride by persulphate activation

Nanocomposites of CuGd_2-xPr_xO₄ with acetylene carbon black were fabricated by a facile microwave-assisted sol-gel method to demonstrate their potential for photocatalytic decomposition of lomefloxacin antibiotics (LMF). With their superb stability and a highly porous structure, the CuGd_2-xPr_xO₄@CB composites exhibited optimum visible light absorption abilities and enhanced charge carrier mobilities. In the persulphate activation process, it efficiently activated persulphate, and 97.5 % of LMF (10 mgL⁻¹) was degraded over 80 min with 20 mg catalyst at natural pH. Gadolinium-based catalysts with Pr³⁺ substitution and the incorporation of carbon black, which offered a large surface area, and the effective inhibition of electron-hole recombination were the primary causes of the enhancement in photocatalytic activity. Scavenging experiments showed that •OH, SO₄•ˉ, •O₂ˉ and holes (h⁺) were the prominent active radicals involved in LMF disintegration. Furthermore, CuGd_2-xPr_xO₄@CB composites possessed good stability and reusability over four cycles, indicating their viability for practical application in environmental remediation.