Enhanced adsorption and visible-light photocatalytic degradation of CIP by CdS QDs-Decorated Mn-doped NH2-UiO-66

CdS Quantum dots (QDs) interspersed on the surface of Mn-UiO-66-NH2 (hereafter abbreviated as CdS QDs@Mn-UiO-66-NH2) Z-scheme heterojunction composites were synthesized by solvothermal method for the removal of ciprofloxacin (CIP) under visible light irradiation. The influences of the doping content of Mn and the initial concentrations of CIP on the adsorption capacity and photocatalytic performance were investigated in detail. Compared to the pristine CdS and Mn-UiO-66-NH2, the fabricated CdS QDs@Mn-UiO-66-NH2 composites exhibited enhanced adsorption and photocatalytic capabilities, especially for the CMU-5 with 10 % Mn doping showing around 52.5 % adsorption removal efficiency and about 92 % photocatalytic removal efficiency for CIP (30 mg/L). Various technologies such as XPS, TG and UV–vis DRS have confirmed that the superior catalytic performance of CMU-5 is ascribed to the d-d transitions improving the utilization of visible light after the coordination of the transition metal and the presence of a heterojunction with a tight interfacial structure enhancing the charge transfer. The possible intermediates in the photodegradation process of CIP were detected using gas chromatography-mass spectrometry (GC-MS).