Apple stem as a high performance cellulose based biosorbent for low cost and eco-friendly adsorption of crystal violet from aqueous solutions using experimental design: Mechanism, kinetic and thermodynamics

In this work, apple stem as a novel cellulose based biosorbent, was used for adsorption of crystal violet from aqueous solution. The biosorbent was characterized by SEM and FT-IR. The effect of dominant parameters including pH, time, temperature, amount of biosorbent, and initial dye concentration on the adsorption of crystal violet were studied. Experimental design was used to describe the adsorption (%) as a function of the parameters via response surface methodology. At experimental optimum conditions consisting pH of 10, time of 20 min, temperature of 35 degrees C, amount of biosorbent of 20 mg, and initial dye concentration of 100 mg L-1, the dye removal (%) of 96.0 +/- 0.5 was acquired. The results of adsorption isotherm studies affirm the fitness and accordance of experimental data in Langmuir model with maximum adsorption capacity of 153.85 mg g(-1). The kinetic and thermodynamic parameters were assessed and the positive increment Delta H degrees and increment Delta S degrees values revealed the endothermic nature of the adsorption process. Moreover, the kinetic of crystal violet adsorption onto the apple stem conformed the pseudo-second order kinetic model. (C) 2021 Elsevier B.V. All rights reserved.