Production of activated carbon from decayed wood: Surface modification using high-frequency DBD plasma for enhanced Rhodamine B dye adsorption – A kinetic and equilibrium study

The potential of decayed wood was investigated as a raw material to produce activated carbon. Both sound and decayed beech wood specimens were subjected to chemical activation with ZnCl2 at a carbonization temperature of 400 °C and 75% impregnation ratio to produce activated carbon. The produced activated carbon was tested using Brunauer–Emmett–Teller, Fourier transform infrared, scanning electron microscopy, and thermogravimetric analyses to investigate its properties. The activated carbon was used to adsorb rhodamine B dye in an aqueous solution. Additionally, to investigate the impact of activated carbon surface modification on the adsorption of rhodamine B dye, both kinds of activated carbon underwent surface modification using dielectric-barrier discharge (DBD) plasma at a high frequency of 20 kHz in the air atmosphere for 20 min at a voltage level of 10 kV. The modification of the activated carbon substantially improved its characteristics, resulting in a 20% increase in rhodamine B removal for the activated carbon derived from sound wood and a 12% increase for the activated carbon derived from decayed wood. The utilization of DBD air plasma in this method is suitable because of its simplicity, cost-effectiveness, and improved adsorption capacity in activated carbon.