Comparative Adsorption Behavior of Malachite Green Dye onto Charred and Aminated Sal (Shorea robusta) Sawdust from Aqueous Solution

Abstract

Chemically treated Sal sawdust was used to study the adsorption of Malachite Green (MG) dye from an aqueous solution. Raw Sal sawdust (RSSD) was charred and aminated. The surface functional groups of raw and modified adsorbents were determined by Fourier Transform Infrared Spectra (FTIR). The influence of pH on batch experiments, concentration and contact time for charred Sal sawdust (CSSD) and aminated Sal sawdust (ASSD) were investigated. The dye uptake was highest at a pH of 4, and adsorption was found to be 62.63 % and 92.15% for CSSD and ASSD, respectively, at an adsorbent dose of 0.025 g and agitation speed of 190 rotations per minute (rpm). The pertinency of Langmuir isotherm was tested, and the kinetic data was found best fitted for pseudo-second-order. The adsorption capacity of MG dye onto ASSD and CSSD was found to be 91.9 mg/g and 64 mg/g, correspondingly. This showed that ASSD is a more efficient adsorbent than CSSD for excluding MG dye from an aqueous solution.