Adsorption of methylene blue onto biomass-based activated carbon by FeCl3 activation: Equilibrium, kinetics, and thermodynamic studies

► Activated carbon was prepared from date pits by ferric chloride activation (FAC). ► FAC was used to remove methylene blue (MB) from aqueous solutions. ► Surface area of 780.06 m2/g was characterized for FAC. ► Maximum MB capacity of 259.25 mg/g was reported using Sips isotherm. ► The kinetic data were well described by pseudo-second order model.