Development of Sulfomethylated Lignin-Based Adsorbent for Methylene Blue Removal

The aim of this study was to develop an adsorbent from acetic acid lignin for methylene blue removal. Acetic acid lignin was sulfomethylated and then crosslinked with epichlorohydrin to obtain the adsorbent. FT-IR spectra suggested that sulfonic acid groups existed on the sulfomethylated lignin. The content of sulfonic acid groups was 0.39 mmol/g. Scanning electron microscopic images showed that the adsorbent was a porous material. Adsorption results showed that the amount of methylene blue adsorbed increased with increases in the initial solution pH, solution methylene blue concentration, and contact time. The kinetic data were fitted the pseudo-second-order kinetic model well. The equilibrium data was interpreted by the Langmuir and Freundlich isotherms. The monolayer adsorption capacities of the adsorbent for methylene blue adsorption can be up to 276.53 mg/g at 30 degrees C.