Grapevine wood biomass as a new bio-adsorbent for methylene blue: equilibrium, thermodynamic, kinetic, and isotherm analyses, both linear and non-linear

Abstract

Recent studies have focused a significant amount of attention on the problem of dyes in water because of their adverse outcomes for the environment and people’s life. In the current work, the adsorption capacity of the sawdust of grapevine wood (GVW) from agricultural waste was employed as a new inexpensive, and green biosorbent via a batch adsorption process. Sulfuric acid was applied to grapevine wood to activate the sorbents for methylene blue (MB) elimination from the solution medium under varied parameters, including temperature, pH, original MB content, contact time, and adsorbent dimensions. The optimum capacity for adsorption ( q max ) of 220.51 mg·g –1 at 293 K was obtained after 180 min of solid/liquid contact with 1 g·L –1 activated grapevine wood (GVWA) sawdust. The Freundlich and pseudo-second-order systems were given the optimal isotherm and kinetic results for MB biosorption onto GVWA sawdust using linear and non-linear regression techniques. The findings for MB biosorption exhibit that non-linear regression was the best approach to choosing the optimum kinetic and isotherm models. The calculated standards for entropy change, standard enthalpy change, and standard Gibbs free energy change demonstrated that the adsorption dynamic was exothermic, spontaneous, and advantageous. Our findings suggest that sustainable and cost-effective GVWA is a suitable candidate for removing emerging contaminants like MB from contaminated waters.