Plasma-modified wood sawdust waste for the removal of reactive blue II anionic dye from aqueous solution

Abstract

The Removal of an anionic Reactive Blue 2 (RB2) dye in an aqueous solution was successfully achieved using a plasma-modified agricultural biomaterial waste. Sawdust from Moabi (Baillonellatoxisperma) and Sapelli (Entandrophragmacylindricum) was modified using non-thermal gliding arc plasma. The natural raw materials and plasma treated were characterized by Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), XRD, Chemical analysis by Fluorescence, Sorption Analyser, and Zetametry. Experimental parameters such as initial pH, contact time, adsorbent dose, initial RB2 concentration, and temperature were optimized. The results showed that the removal of Reactive Blue 2 dye was favorable at acidic pH conditions with the maximum capacity going from 172,85 to 200,91 mg.g-1 to 98,19 and 149,02 mg.g-1  respectively for raw and plasma-treated Sapeli and Moabi. The Avrami fractional-order kinetic provided the best fit to the experiments data and the thermodynamic adsorption data of untreated (SSB and SMB) and plasma-treated (SSM and SMM) sawdust followed an exothermic process. This work demonstrated that non-thermal plasma modified wood sawdust can be a good alternative absorbent for the removal of dye pollutants from an aqueous solution.