Design of a light-responsive 3D Cu-MOF for selective photodegradation of oxytetracycline remediation

Photocatalytic degradation offers a highly efficient and ecofriendly way of removing organic pollutants such as antibiotics, from the water under visible light, though the design of effective photocatalyst remains a key challenge. In this study, a 3D new copper-based metal–organic framework (Cu-MOF), [Cu2(BPYP)(CPA)2·2DMA] (1), was synthesized hydrothermally using camphoric acid (H₂CPA) and 2,5-bis(pyrid-4-yl)pyridine (BPYP) as organic linkers. Structural was characterization by FT-IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction confirmed that 1 features a paddle-wheel dinuclear Cu(II) architecture, with each Cu center adopting a distorted trigonal bipyramidal geometry. The carboxylate groups exhibit a syn–syn bridging mode between the two Cu ions. Photocatalytic studies confirmed that 1 effectively degrades trace (ppb) concentrations of various antibiotics, including oxytetracycline (OXY), secnidazole (SIZ), sulfasalazine (SLA), sulfamethoxazole (SMT), and bicalutamide (BCL), following pseudo-first-order kinetics. Under visible-light irradiation, OXY degradation reached 91.45 % within 60 min. Radical trapping examinations show that superoxide radicals (·O2−) play a dominant role in the photocatalytic mechanism. Reusability tests confirmed the material's structural robustness and sustained catalytic performance over four successive cycles. These findings highlight the potential of 1 as an efficient and reusable photocatalyst for the removal of pharmaceutical pollutants from aqueous environments.