Removal of methyl orange by activated carbon modified by silver nanoparticles

In this work, the removal of methyl orange (MO) dye by adsorption on silver nanoparticles (AgNPs) coated activated carbon (AC) has been studied. The effect of various process parameters has been investigated by the column adsorption technique. Equilibrium adsorption data of MO were carried out at room temperature. Using AgNPs-coated AC, 72.5 % of MO was removed, whereas only 50.0 % when using AC after reacting for 16 h with an initial MO concentration of 2 mg/L (pH = 7). The equilibrium time is independent of the initial dye concentration and the percentage removal of MO increased with increase in contact time. The adsorption data were analyzed using adsorption isotherm. The characteristic parameters for isotherm and related correlation coefficients were determined from graphs of their linear equations. Kinetic studies showed that the adsorption of MO followed pseudo-second-order kinetics. AgNPs-coated AC is found to be suitable adsorbent for the adsorption of MO. Desorption studies were made to elucidate recovery of the adsorbate and adsorbent for the economic competitiveness of the removal system. The AgNPs-coated AC was successfully recycled for 10 successive adsorption–desorption cycles indicating its high reusability.