Optimization and evaluation of CBSOL LE red wool dye adsorption from aqueous solution onto commercial activated carbon

Adsorptive removal of CBSOL LE red wool dye form aqueous solution onto commercial activated carbon (CAC) was investigated in a batch system. Various process parameters like pH, dosage of CAC (m) and adsorption time (t) were considered and optimized with full factorial central composite design under response surface methodology. At optimized parameters, kinetic and thermodynamic studies were performed and adsorption equilibrium data were represented using Freundlich, Langmuir and Redlich–Peterson (R–P) isotherm models. Also, diffusivity was calculated for the rate-limiting step in the adsorption process. Optimum process parameters were found to be m = 2.92 g/100 ml, t = 6.75 h and pH = 3.95, and at these optimized parameters, % removal of CBSOL LE red wool dye (Y) was found to be 86 %. Pseudo-second-order kinetic was found to best fit the adsorption kinetic data. Freundlich and R–P isotherms were found to best represent the equilibrium adsorption data. Diffusivity for the intra-particle diffusion was found to be 9.676 × 10−8 and 1.396 × 10−8 m2/s at initial concentration of CBSOL LE red wool dye (C 0) of 50 and 100 mg/l, respectively.