Xanthan or esterified xanthan/cobalt ferrite-lignin hybrid materials for methyl blue and basic fuchsine dyes removal: equilibrium, kinetic and thermodynamic studies

In this study, new adsorbents based on xanthan (XG) or esterified xanthan (XGAC) and ferrite-lignin hybrids were obtained and characterized by using the dynamic vapor sorption (DVS) method, infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The porosity, swelling ratio and point of zero charge (PZC) of the adsorbents were also evaluated. Batch adsorption experiments have been performed to determine the adsorption capacity of the adsorbents for Methyl Blue (MB) and Basic Fuchsine (BF). Ferrite-Lignoboost (R) lignin and ferrite-organosolv lignin hybrid materials (CFLB and CFLO) presented the highest adsorption capacity for MB dye (44.73 and 37.54 mg/g), while the adsorbents based on xanthan and ferrite-lignin hybrids (XG/CFLO and XG/CFLB) retained the highest quantities of BF dye (36.23 and 33.33 mg/g). The chemical nature of the adsorption process was determined, the analyzed data being better fitted to the pseudo second order (PSO) kinetic model. The data analysis showed that the adsorption process followed Langmuir, Dubinin-Radushkevich and Jovanovic isotherm models. All the studied adsorption processes were endothermic (Delta H degrees > 0) and the positive values of the entropy (Delta S degrees > 0) indicated disorder at the interface between the adsorbent and the dye solutions. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

New adsorbents based on xanthan or esterified xanthan and ferrite-lignin hybrids were characterized through various methods. The adsorption capacity of these adsorbents for Methyl Blue and Basic Fuchsine was determined, with different materials showing varied adsorption capacities. The adsorption process followed multiple isotherm models and was found to be endothermic with disorder at the adsorbent-dye interface.