Improvement of adsorption properties of coconut shell activated carbon using atmospheric pressure dielectric barrier discharge plasma jet

Surface modification through the use of atmospheric pressure dielectric barrier discharge plasma jet represents a cost-effective and efficient approach. The major advantage of this method lies in the fact that it enhances surface properties without altering the bulk properties. Despite, the impressive mechanical properties exhibited by coconut shell activated carbon, its adsorption capabilities are somewhat lacking. Therefore, the application of dielectric barrier discharge plasma jet treatment at atmospheric pressure becomes necessary to address the deficiency in adsorption properties associated with coconut shells. In this study, a dielectric barrier discharge configuration was generated using Cu wire and Cu tape separated by dielectric glass with an inner diameter of around 6 mm. A circular well with an area of 20 cm2 and a depth of 4 cm was filled with 60 mg of granular coconut shell, which was then subjected to plasma treatment at a voltage of 17 kV for 5 min. The surface of the coconut shell granules exhibited significant improvement following the plasma treatment. Analysis using FESEM micrographs indicated an increase in surface roughness due to plasma etching. Furthermore, FTIR spectra displayed heightened intensity of curve peaks located at 1543.00 cm-1 and 3748.91 cm-1, suggesting the introduction of new functional groups onto the surface of the coconut shell granules after plasma treatment. To evaluate dye adsorption, plasma treated coconut shell granules were combined with crystal violet dye in aqueous solutions at concentrations of 50 and 100 ppm. The absence of distinct peaks in the visible region of the UV-VIS spectrum (300-800 nm) confirmed the successful adsorption of the bluish-green dye by the coconut shell granules.