Mesoporous activated carbon from date stones (Phoenix dactylifera L.) by one-step microwave assisted K2CO3 pyrolysis

Preparation of activated carbon (KAC) from date stones (DS) by microwave K2CO3 activation has been studied. Methylene blue (MB) dye was sufficiently adsorbed on KAC compared to raw DS. The effects of radiation time (4–12 min), radiation power (540–700 W) and impregnation ratio (0.5–2.5 g/g) on the yield and MB uptake of KAC were studied. MB uptake of 460.12 mg/g and 19.99% yield were reported at 8 min radiation time, 660 W radiation power and 1.5 g/g impregnation ratio. The characteristics of KAC were examined by pore structure analysis, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR). The BET surface area and total pore volume were 1144.25 m2/g and 0.656 m3/g, respectively. The equilibrium data were well correlated by Langmuir isotherm compared to Freundlich and Temkin isotherms with maximum Langmuir capacities of 256.15 and 485.44 mg/g on DS and KAC, respectively. Pseudo- second order model showed well representation for adsorption kinetics data.