EXTRACTION AND CHARACTERIZATION OF LIGNIN FROM MOROCCAN THUYA. ITS APPLICATION AS ADSORBENT OF METHYLENE BLUE FROM AQUEOUS SOLUTION

The present investigation includes the extraction of lignin from waste sawdust of the wood industry (Tetraclinis articulata) using sulfuric acid treatment, its characterization and further use for the removal of methylene blue (MB) cationic dye from aqueous media. The extracted lignin was characterized by FT-IR and XRD, its thermal properties were studied using TGA and DSC analyses, and its surface morphology was observed by SEM and EDX. The FT-IR spectra showed homogeneity in the chemical structure of the lignin sample. In the adsorption study, the effects of temperature, contact time, and adsorption concentration of MB were determined. The kinetic study showed that the second-order model gives a better description of the kinetics of the adsorption reaction than the first-order model. The analysis of adsorption isotherms using different classical models showed that adsorption may be governed by the Langmuir isotherm. The thermodynamic parameters were determined from the values of the maximum adsorption capacity and equilibrium constants.