Adsorptive characteristics and microwave dielectric properties of oil palm empty fruit bunch-based activated carbons for dye removal

The present study was aimed to evaluate the adsorptive characteristics and microwave dielectric properties of activated carbons derived from oil palm empty fruit bunch (EFB) prepared by microwave-assisted potassium hydroxide activation at 300 W and 800 W for 5 min. The resultant products were characterized for dielectric properties, BET specific surface area, surface functional groups and methylene blue adsorption. Results show that the microwave-assisted activation yields activated carbons with surface area of 695 m2/g and 1339 m2/g for heating rates (microwave irradiation power) of 300 W and 800 W, respectively and both exhibit more than 95% removal of methylene blue at concentrations higher than 100 mg/L. The dielectric properties revealed a better propensity of activated carbons towards microwave heating especially at a higher heating rate due to high surface area, and possibly high moisture content and carbon content. A greater heating rate or microwave power could turn EFB into activated carbon with a higher surface area and excellent adsorptive properties for pollution abatement.