Biomimic-Inspired and Recyclable Nanogel for Contamination Removal from Water and the Application in Treating Bleaching Effluents

A recyclable and high-efficiency nanoscale adsorbent is prepared from sustainable resources in this study. Inspired by the amino acid and phenolic hydroxyl group in reed root acting as active sites for adsorption, a chemically modified method is employed, where lignin is improved with glycine to prepare a biomimic adsorbent with a synergistic effect of amino acid and phenolic hydroxyl. By blending with nano-Fe3O4, the modified lignin is applied to synthesize lignin derivate magnetic nanogels that adsorb inorganic ions and organic dyes. The maximum capacities of the adsorption are highly improved, whereas unmodified lignin-based adsorbents reveal a low adsorption capacity under the same conditions. The used nanogels are recycled by magnetic separation and regenerated in hydrochloric acid, and the tests are repeated three times. All the regeneration ratios are over 90%, thus ensuring reusability. Finally, the as-prepared nanogels are applied to treat pulp bleaching effluents, revealing one potential application in industry. The designing concept of the recyclable nanogel in this study provides a biomimic strategy of using sustainable resources to treat contamination.