Hybrid Adsorbent Materials Obtained by the Combination of Poly(ethylene-alt-maleic anhydride) with Lignin and Lignosulfonate

Lignin is one of the most available biomass products, but its potential for the development of functional materials has yet to be unleashed. Here, the modification of lignin and lignosulfonate with poly(ethylene-alt-maleic anhydride) [P(E-alt-MA)], a functional polymer of wide industrial use, is accomplished by means of a simple esterification reaction. As a result, hybrid adsorbent materials for water purification can be obtained, which were thoroughly characterized. The combination of P(E-alt-MA) with lignin increased hydrophilicity of the latter, making it dispersible in aqueous environments, while with lignosulfonate it gave rise to a water-insoluble, thus easily recoverable, product. The adsorption properties of the resulting products have been tested against a model water pollutant (methylene blue), demonstrating remarkable adsorption speed (in the order of minutes), adsorption efficiency and stability over a wide range of pH (2–12). Moreover, after the incorporation of magnetite nanoparticles by in situ synthesis, adsorbent materials able to be magnetically recovered were developed.