Development of cation exchanger-based nano-CdS hybrid catalyst for visible-light photodegradation of rhodamine B from water

A new polymeric nanocomposite photocatalyst A15-CdS with large spherical beads (0.70?C0.80 mm in diameter) was fabricated for efficient Rhodamine B (RhB) photodegradation with facile separation during cyclic runs, and photocorrosion, a congenital drawback of CdS, was successfully inhibited for A15-CdS. The nanocomposite catalyst was obtained by impregnating CdS nanoparticles within porous polymeric cation exchanger A15 through a facile inner-surface deposition. CdS nanoparticles (<20 nm) immobilized in A15 were deliberately distributed within an outside ring-like region of 40?C50 ??m in depth, which is dominant for photoreaction because visible light is not expected to permeate through the inner region of nontransparent A15. As expected, efficient RhB photodegradation by A15-CdS was achieved under visible light irradiation, and large-size A15-CdS beads are expected to result in their facile separation from solution for repeated use. More significantly, negligible photocorrosion for the hybrid catalyst A15-CdS was demonstrated by the constant photodegradation efficiency and negligible CdS loss during five-cycle runs. The results indicated that nano-CdS immobilization within A15 would greatly improve the applicability of CdS nanoparticles in practical environmental remediation.