Synthesis of Ag/Fe/CAC for colour and COD removal from methylene blue dye wastewater

This study investigated the performance of commercial activated carbon modified with Ag/Fe nanoparticles for colour removal and chemical oxygen demand reduction from methylene blue dye wastewater under visible light irradiation. Central composite design of the response surface methodology was used to optimize the operating conditions with a minimum number of experiments. There are three operating variables namely adsorbent dosage (g) (1.5-3.5 g), pH of dye wastewater (pH 4-10) and contact time (min) (60-120 min) via a total 20 of experiments were carried out to optimize the combination effects of the parameters. In the Ag/Fe/CAC study, under optimum operating conditions of 1.79 g/L, pH 5.75 and 115 min of contact time, chemical oxygen demand reduction and colour removal were 37 and 94%, respectively. The error differences between predicted and experimental data were < +/- 5%. The properties of Ag/Fe/CAC were characterized by Fourier transform infrared ray, X-ray diffraction and high-performance liquid chromatography analysis and scanning electron microscopy. The isotherm and kinetics study indicated that the experimental data fitted to Langmuir and pseudo-second-order models, respectively.