Acceleration of methylene blue adsorption onto activated carbon prepared from dross licorice by ultrasonic: Equilibrium, kinetic and thermodynamic studies

Adsorption of methylene blue (MB) onto activated carbon (AC) prepared from dross licorice as adsorbent was studied following full AC characterization by FT-IR spectroscopy, scanning electron microscopy and BET (Brunauer, Emmett, and Teller). The effects of variables were studied and optimized by a central composite design (CCD) combined with response surface methodology (RSM) and desirability function (DF). The good agreement between experimental and predicted data at optimum values of all variables was explored. The optimum condition set as follow: 20 mg L−1 of MB concentration, pH 7 for sample solution, 0.20 g of AC and 16 min sonication as mass transfer process. The small amount of proposed adsorbent (0.2 g) was applicable for removal of MB (RE > 95%) at 16 min with high adsorption capacity (82.9 mg g−1).