Preparation and examination of activated carbons from date pits impregnated with potassium hydroxide for the removal of methylene blue from aqueous solutions

The effect of chemical activation on the adsorption capacity of raw date pits towards the basic dye Methylene Blue (MB) was investigated. The raw material was impregnated with 30 wt% KOH solution followed by carbonization at 600°C for 2 h and activation with CO₂ at 800°C for 1 h. The adsorption capacity increased from 80.3 mg/g to 123.1 mg/g upon chemical activation. Three simplified models including the pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to test the adsorption kinetics. The rates of adsorption were found to conform to pseudo-second-order kinetics with high correlation. The equilibrium results for MB adsorption on the activated carbon obtained from date pits were well fitted by the Langmuir isotherm equation.