Tuning the photocatalytic activity of TiO2 by Ag loading: Experimental and modelling studies for the degradation of amlodipine besylate drug

Abstract In this research work, a heterogeneous photocatalytic process has been adopted for emergent pharmaceutical effluents treatment using amlodipine besylate as a contaminant molecule and Ag–TiO2 as a nanocatalyst. The influence of amlodipine besylate initial solution pH and concentration, Ag doping content, catalyst mass, and contact time has been investigated. The obtained results indicate that Ag doping induces rutile-anatase phase transformation and improved the surface characteristics (higher surface area and larger average pore volume). The photodegradation of amlodipine besylate is very effective; the highest performance is found to be 100% for 1% doped TiO2 nanocatalyst under optimum conditions (pH 6, 0.5 g L-1 catalyst content, 100 min). The experimental data of the photodegradation process are found to obey the Lagergren kinetic model. Besides, the overall reaction rate is most likely governed by the intra-particular mass diffusion of amlodipine besylate, regardless of the process experimental conditions.