Adsorption of diclofenac sodium in aqueous solution using plasma-activated natural zeolites

Abstract

Plasma-activated zeolites were used in the removal of diclofenac sodium (DCF) via adsorption in an aqueous solution. The natural zeolites were exposed to 13.56 MHz radio frequency-driven plasma discharge using argon as the working gas. Results have shown an increase in adsorption capacity of DCF to 64% from 52% using the plasma-treated and untreated zeolites, respectively. Further analysis showed no significant changes in the bulk properties of the zeolite after plasma exposure. However, an apparent increase in surface porosity was observed after treatment due to etching and ablation effects of the impinging energetic particles from the discharge. The adsorption of DCF followed the Freundlich isotherm model suggesting that the modified surface is heterogeneous allowing multilayer adsorption. This work realized the enhancement of adsorption capacity of natural zeolites via plasma treatment. The plasma-treated zeolites are inexpensive candidates for the removal of emerging pharmaceutical wastes in wastewater such as DCF. Keywords: Plasma treatment, Zeolite, Adsorption, Diclofenac