Optimization of process parameters for adsorption of methylene blue by reduced graphene oxide/layered double hydroxide composite

Abstract

Dyes that are present in industrial effluent are classified as hazardous compounds. Using the adsorption method, which provides high efficiency at low cost, in the uptake of dyestuffs is an important application area. In this study, the adsorption process applied to remove methylene blue (MB) from aqueous medium was optimized with Box-Behnken design (BBD) based on important variables. Initial MB concentration (iMBc), contact time (CT) and pH value were taken as process parameters. Reduced graphene oxide (rGO)/layered double hydroxide (LDH) composite was used as the adsorbent. The reduced graphene oxide (rGO) composite used in the adsorption experiments was obtained by the co-precipitation method. The obtained adsorbent was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), N2 adsorption/desorption, and zeta potential analyses. The maximum removal efficiency of MB was obtained in the adsorption process that took place in 30 min at pH 9 at a 10 ppm iMBc. The maximum uptake capacity was achieved at an initial concentration of 100 ppm and 30 min at pH 9. Initial MB concentration (iMBc) and pH were found to be the parameters that had the most influence on the adsorption of MB.