One-step Ag-doped ZnO nanoparticle synthesis for textile azo dye sorption and antibacterial activity

This study presents the successful synthesis of silver-doped zinc oxide (Ag-ZnO) aerogel using a modified sol–gel process under supercritical solvent conditions. Combining the adsorption properties of zinc oxide with the antibacterial effects of silver, the Ag-ZnO nanoparticles, with an average size of less than 65 nm and a surface area of 16.3 m².g⁻¹, were analyzed for their effectiveness in adsorbing Reactive Black 5 (RB5) and their antibacterial activity. Spectroscopy analysis confirms the Ag-doping. Response surface methodology was used to optimize the parameters for dye removal, revealing a color removal yield of 72% under optimal conditions. Adsorption kinetics followed a pseudo-second-order model and follow the Langmuir model. Adsorption isotherm showed a maximum adsorption capacity of 23.8 mg.g⁻¹. Thermodynamic analysis indicated the adsorption process was spontaneous and exothermic. Antibacterial tests showed complete inhibition of Pseudomonas aeruginosa and Salmonella typhimurium at a nanoparticle concentration of 1 g.L⁻¹.