Methylene blue removal using prepared activated carbon from grape wood wastes: adsorption process analysis and modeling

An adsorption study has been conducted for activated carbon obtained from grape wood wastes to assess their capability to remove methylene blue (MB) from the aqueous solutions. The properties of prepared activated carbon were characterized using FTIR, BET and SEM analyses. The effects of independent variables such as initial concentration of MB (100-500 mg L-1), initial pH of solution (3-11), adsorbent dosage (0.25-12.25 g L-1) and contact time (10-90 min) on the MB adsorption have been optimized using response surface methodology. The highest MB removal efficiency was 98% when pH, MB and adsorbent dosage were 11, 100 mg L-1 and 12.25 g L-1, respectively. The experimental data have been tested using Langmuir and Freundlich isotherm models, and the achieved data were fully fitted with the Langmuir model (R-2 = 0.99), which indicates the monolayer adsorption. The adsorption kinetics well followed by the pseudo-second-order model with R-2 of 0.99. This prepared activated carbon as a low-cost and eco-friendly adsorbent can be used widely for water and wastewater treatment.