Efficient adsorption of malachite green from wastewater using agricultural biosource waste: Kinetic, isothermal, thermodynamic studies and mechanisms analysis

Abstract

Adsorption on biomass has gained popularity recently as a method for reducing pollutants in wastewater before release. This work investigates the adsorption of malachite green (MG) onto sugarcane bagasse (SCB). To optimize the process, the mass of the bio-adsorbent, contact time, temperature, and pH of the MG solution were investigated with the adsorbate and the adsorbent. The observed results indicate that MG adsorption on SCB is more effective in the environment because of the electrostatic interactions between the organic cations of the dye and the negatively charged SCB surface in this pH range. In ideal circumstances, SCB removes 97% of MG. The adsorption of MG on SCB is better described by the pseudo-second-order model, according to adsorption kinetics modeling. UV-Vis spectrophotometers were used to analyze the fluids under study and determine the dye concentration. Malachite green has a limit of quantification (LOQ) of 0.1 mg L-1 and a limit of detection (LOD) of 0.06 mg L-1 using UV-Vis spectrophotometry. The measuring range of the procedure is 0.1 to 30 mg L-1, which guarantees precise and repeatable results. According to adsorption isotherm modeling, the Freundlich and Langmuir models best describe MG’s adsorption on SCB. Given that both the Freundlich parameter 1/n and the Langmuir separation coefficient RL are smaller than 1, it is clear that MG’s bio-adsorption on SCB is beneficial. The study’s findings demonstrate that SCB, an underutilized agricultural waste, is a reasonably priced bio-adsorbent with a substantial capability for treating wastewater that contains dyes.