Dielectric and adsorptive properties of potassium hydroxide-treated castor residue carbons

Abstract

The fundamental understanding about dielectric properties is not completely understood even though it is crucial in microwave-assisted heating. The present work was aimed at evaluating the dielectric properties of reagent mixtures and solids of potassium hydroxide-treated castor residue carbons at varying frequencies and temperatures. Chemical treatment at solid mass ratios (KOH pellet:castor residue) of 0.0 to 2.0 in 50 mL water was carried out using a microwave oven at 70% intensity. The dielectric properties were determined using an open-ended co-axial probe. Results show that the dielectric properties of materials changed with frequency, temperature, water content and ionic strength. Also, the presence of potassium hydroxide solution aids in improving the propensity of castor residue to be heated via microwave. The potassium hydroxide-treated carbons exhibit a 90% removal efficiency of methylene blue at Co = 189 mg/L.