Enhanced adsorption of toluene using nano silver-modified activated carbon derived from Ricinodendron heudolitii shells: A comparative study"

Abstract

Considering the risk of toluene exposure in water resources, researchers have been prompted to conduct experiments to remove them from aqueous solutions. This study investigates the use of Ricinodendron Heudolitii shells as a precursor for extracting an adsorbent (activated carbon) through chemical activation with phosphoric acid (H3PO4). The obtained activated carbon was then modified with Quercetagetin stabilized silver nanoparticles (Qtg-Ag/AC), and characterized for thermogravimetric analysis (TGA), Fourier-transformed infrared spectroscopy (FTIR), diffraction light scattering, Powder XRD, and scanning electron microscopy (SEM/EDX). The adsorption characteristics such as kinetics, mechanism and isotherms of toluene were studied. The kinetic data were analyzed using a pseudo-first-order, pseudo-second-order kinetic equation elovick and intraparticle diffusion model. The pseudo-first-order and pseudo-second-order kinetic model describes experimental data better than elovich and intraparticle kinetic model. The results show that Qtg-Ag/AC exhibits superior adsorption capacity (39.352 mg g−1) compared to AC (30.093 mg g−1). Langmuir, Freundlich and Tenkim model for AC and Qtg-Ag/AC described the equilibrium data better. In order to determine the best-fit kinetic model for each system, two error analysis methods, namely, chi-square (χ2) and residual mean squared error (RMSE) were used to evaluate the data. The outcomes of the study demonstrate that our modified (Qtg-Ag/AC) can be a good prototype for the adsorption of toluene from wastewater.