Preparation and Photocatalytic Degradation Performance of C@CdMnS to Tetracycline Hydrochloride.

CdMnS solid solutions were synthesized by incorporating Mn into CdS and the optimal ratio of Mn to Cd was explored via photocatalytic degradation performance for tetracycline (TC). Subsequently, the composite catalyst C@CdMnS was prepared by loading CdMnS onto the biomass gasification carbon residue (C) by hydrothermal method and characterized by various characterization tests. The optimal TC photodegradation condition and degradation mechanism catalyzed by C@CdMnS was investigated. The results showed CdMnS had the optimal photocatalytic degradation efficiency, which is about 1.3 times that of CdS. The TC photodegradation efficiency by C@CdMnS prepared at the mass ratio of C to CdMnS of 1:2 was the best, which was 1.24 times that of CdMnS and 1.61 times that of CdS. Under the optimal conditions (visible light irradiation for 60 min, C@CdMnS of 20 mg, 40 mL TC solution of 40 mg/L), the TC degradation efficiency was 90.35%. The degradation efficiencies of 20 mg/L levofloxacin, ciprofloxacin, and 40 mg/L oxytetracycline catalyzed by C@CdMnS range from 89.88% to 98.69%. In the photocatalytic reaction system, •O and h are the dominant active species, which directly participate in the photocatalytic degradation reaction of TC, and •OH contributes little. The work provides a strategy to improve the photocatalytic performance of CdS for photocatalytic degradation antibiotics, and opens an interesting insight to deal with solid waste from biomass gasification.