Aminated Sodium Lignosulfonate for Efficient Adsorption of Methyl Blue Dye

The research aims to resolve water pollution generated by dye wastewater. In this paper, the aminated sodium lignosulfonate (AELS) was prepared through the Mannich reaction, and the synthesis conditions were optimized using orthogonal experiments to determine the best amination conditions. The successful preparation of AELS was demonstrated through the use of FT-IR, XRD, TG, SEM and XPS characterization techniques. Then, the adsorption capacity of Methyl blue (MB) by AELS was compared in a range of different circumstances, like pH, adsorbent dose, initial concentration, time, and temperature. Additionally, the kinetics, isotherms, and thermodynamic properties of the AELS adsorption for MB were studied and discussed. The results indicated that the fitting results were consistent with the pseudo-second-order kinetic model and Langmuir isotherm model, in accordance with the mechanism of single-molecular-layer chemisorption. And the adsorption of MB by AELS was a spontaneous and endothermic process. Upon completion of five adsorption experiments, the adsorption capacity of MB by AELS was determined to be 107.95 mg g-1, which was 5.3% lower than the first experiment. This research promotes the effective use of natural resources and allows for the sustainable use of lignin and the advancement of new applications for it.