equilibrium and kinetic modeling studies for the adsorption-desorption of methyl violet 10b onto leather waste

In this study, vegetable tanned leather waste of cow (vtlw-c) is used as adsorbent for removing methyl violet 10b dye from aqueous solution. the vtlw-c adsorbent was characterized by ftir and sem in order to evaluate its surface properties before using in adsorption experiments. batch adsorption method was applied to study the effect of different factors such as weight of leather waste, time of shaking, and starting concentration of methyl violet 10b dye. different isothermal models such as langmuir, freundlich, temkin and dubinin-radushkevich (d–r) were used to analyze the experimental data. kinetic study proceeds using (pfo) kinetic model and (pso) kinetic model. the results showed better agreement with the freundlich model; this means that the adsorption process was performed on a heterogeneous surface, and the maximum adsorption amounts of vtlw-c is 29.411 mg/g. from the value mean, free energy (e) for d–r isotherm the adsorption followed a physisorption nature process. thermodynamic study proved that the adsorption process is exothermic and spontaneous. experimental kinetic results are compatible with (pso) model with correlation coefficients r2 > 0.9998. finally, the desorption and regeneration showed that the adsorbent could be easily reused related to the weak vanderwasll’s force that accompanied the physical adsorption. vtlw-c is used as a good and low cost adsorbent to remove dye from wastewaters.