Gossypium biochar supported plasmonic nZVAg-TiO2 nanocomposite for enhanced visible-light-driven photocatalytic degradation of ciprofloxacin: synthesis, characterization, and performance evaluation

The increasing occurrences of antibiotics such as ciprofloxacin (CIP) in aquatics poses significant ecological and public health concerns due to their persistence and role in promoting antimicrobial resistance. To efficiently photocatalyzed CIP degradation under visible light, gossypium plant-based biochar nanocomposite of zero valent silver-doped titanium dioxide as a multifunctional photocatalyst (nZVAg-TiO 2 @BC) was synthesized using a cost-effective two-step synthesis chemical reduction method, followed by calcination under a N₂ atmosphere. Detailed characterization using FTIR, XRD, SEM-EDX, TEM, TGA, XPS, PSA, and zeta potential analysis confirmed the photocatalyst structural integrity, crystallinity, and stability. The nZVAg-TiO 2 @BC nanocomposite exhibited excellent photocatalytic performance, achieving 96.6 % CIP degradation in 60 min under visible light irradiation without H 2 O 2 addition. Under optimized conditions (40 mg/L CIP, 0.3 mL H 2 O 2 ), complete (100 %) removal was attained, highlighting the system's adoptability to operational parameters. This enhanced activity arises from the synergetic effects of Ag doping, which extends light absorption through plasmonic resonance and biochar support, which promotes charges separation and suppresses e − /h + recombination. Kinetic analysis followed a pseudo-first-order model with a rate constant: 0.05256 min −1 , while recyclability tests demonstrated stable performance (>82 %) over five cycles. These finding highlights nZVAg-TiO 2 @BC as a sustainable and scalable photocatalyst for water treatment technologies. • The nZVAg-TiO 2 @Biochar was prepared via Chemical reduction N 2 calcination route. • The hybrid design achieves superior charge separation and visible-light absorption. • Achieves excellent visible-light-driven photocatalytic degradation of ciprofloxacin. • H 2 O 2 addition induces a Fenton-like reaction pathway, enabling complete CIP degradation. • Systematically investigates operational parameters, interference, and reusability for practical application.