Photocatalytic degradation of tetracycline in aqueous systems under visible light irridiation using needle-like SnO2 nanoparticles anchored on exfoliated g-C3N4

Background Pharmaceuticals is one of the groups of contaminants of emerging concern that are resistant to decomposition or removal by most of the existing water and wastewater treatment procedures, hence the need to develop techniques to facilitate the removals of this group of organic contaminants from water systems. In this study, needle-like SnO 2 nanoparticles was synthesised and loaded on exfoliated g-C 3 N 4 nanosheet through a hydrothermal method, for use as sensitive visible light induce-photocatalyst for the decomposition of tetracycline in aqueous systems. The synthesised composites was characterized and analysed for the nature of the heterojunction between the SnO 2 nanoparticle and g-C 3 N 4 nanosheet using microscopic and spectroscopic techniques. Results The composites were of improved surface properties and enhanced visible-light absorption. The synthesised SnO 2 /g-C 3 N 4 nanocomposites with various amounts of SnO 2 (10–50 mg), employed in the degradation of tetracycline under visible light irradiation, were of good degradation efficiency. The degradation efficiencies of tetracycline by 1 wt.%, 2 wt.%, 3 wt.% and 5 wt.% SnO 2 /g-C 3 N 4 photocatalyst were 81.54%, 90.57%, 95.90% and 92.15% as compared to g-C 3 N 4 and SnO 2 with 40.92% and 51.32% degradation efficiencies. The synergistic interaction between the needle-like SnO 2 and exfoliated g-C 3 N 4 nanosheet promoted the separation of photogenerated electron holes pairs, which enhanced their migration rate between SnO2 and g-C3N4 heterojunction, thereby facilitating the degradation of tetracycline. The · O 2 − was noted to be the major reactive species in the photocatalytic of the 3 wt.% SnO 2 /g-C 3 N 4 nanocomposite. Conclusion The fabricated SnO 2 nanoparticles anchored on exfoliated g-C 3 N 4 showed good performance for the decomposition of tetracycline in water, with possible application on other pharmaceuticals having same moiety (similar chemical structures).