Syntheses of Ag[Cu@Ag]\\APTMS\\boehmite as a photocatalyst for methylene blue degradation in batch and continuous flow systems under visible light

Abstract

A novel nano-composite photo-catalyst, called Ag[Cu@Ag]\\APTMS\\boehmite, was developed and tested for the degradation of methylene blue (MB) dye as a representative of dye pollutants. The synthesized boehmite nanoparticles (NPs) were functionalized by 3-aminopropyltrimethoxysilane and then anchored by Cu@Ag core–shell NPs. The MB degradation was investigated in the batch and continuous flow-through system. In the batch system, the MB solution was degraded by synthesized photo-catalyst under irradiation by visible light (500-W lamp) and solar light. In this system, different parameters including pH, catalyst dosage, initial dye concentration, and time were optimized. The optimum condition obtained for photocatalytic rate was at pH = 6, an initial dye concentration of 10 mg.L−1, catalyst dosage of 2 g.L−1 and a reaction time of 47 h under visible light irradiation. The MB solution was degraded by 80.3% under visible light irradiation over 34.7 h, and it was degraded by 40.7% over 8 h under solar light irradiation in the optimum condition. In the continuous flow-through system, the MB degradation was studied by considering initial dye concentration and flow rate as variables. Results indicated that the MB degradation rate increased by decreasing the initial concentration of MB and flow rate, as seen 90.4% of initial concentration reduced in 8 h under solar irradiation.