Mahboube Shirani

In this work, apple stem as a novel cellulose based biosorbent, was used for adsorption of crystal violet 22 from aqueous solution. The biosorbent was characterized by SEM and FT-IR. The effect of dominant 23 parameters including pH, time, temperature, amount of biosorbent, and initial dye concentration on the 24 adsorption of crystal violet were studied. Experimental design was used to describe the adsorption (%) as 25 a function of the parameters via response surface methodology. At experimental optimum conditions 26 consisting pH of 10, time of 20 min, temperature of 35 °C, amount of biosorbent of 20 mg, and initial dye 27 concentration of 100 mg L-1, the dye removal (%) of 96.0 ± 0.5 was acquired. The results of adsorption 28 isotherm studies affirm the fitness and accordance of experimental data in Langmuir model with 29 maximum adsorption capacity of 153.85 mg g-1. The kinetic and thermodynamic parameters were 30 assessed and the positive ΔH° and ΔS° values revealed the endothermic nature of the adsorption process. 31 Moreover, the kinetic of crystal violet adsorption onto the apple stem conformed the pseudo-second order 32 kinetic model.