Construction of ZCS/Cu₃P/AgCl Composites for Enhanced Removal of Rhodamine B: Performance and Mechanism

Based on the excellent adsorption, photosensitization and electron transfer properties of biochar, this paper constructed a composite material with the synergic effect of adsorption and photocatalysis to realize the integrated adsorption-enrichment and degradation of Rh B. Hence, a novel efficient ZCS/Cu₃P/AgCl adsorption-photocatalyst is synthesized and characterized by various testing methods. The efficient removal of dye Rh B is achieved through a synergistic effect between adsorption and photocatalytic degradation. Photocatalytic experiments showed that all the ZCS/Cu₃P/AgCl composites with different AgCl content exhibit superior photocatalytic activity for Rh B degradation, and when the content of AgCl is 31%, the photocatalytic activity is the best. After 30 min of dark adsorption, 30% of Rh B was removed by adsorption, and 98.76% of Rh B was removed after continuous visible light irradiation for 20 min. The kinetic constant of 31%-ZCS/Cu₃P/AgCl composite was 0.346 min^–1, which is about 24.7 and 3.8 times that Cu₃P (0.014 min^–1) and AgCl (0.091 min^–1), respectively. Moreover, photo-luminescence and photoelectrochemical experiment confirmed that the surface of ZCS/Cu₃P/AgCl is exposed to more active sites, the charge separation process is enhanced and the photogenerated electron–hole recombination efficiency is reduced compared with Cu₃P and AgCl. Finally, h⁺ and ·O \(_{2}^{ - }\) are identified the main active species in the photocatalytic reaction system, and a possible photocatalytic mechanism was put forward. ZCS/Cu₃P/AgCl composites have excellent photocatalytic performance and recyclability, and are expected to be an important material to solve dye pollutants in water.