Review of the synthesis and applications of deep eutectic solvent-functionalized adsorbents for water treatment

Recently, new knowledge about the functionalization and synthesis of adsorbent materials for water treatment applications has been achieved using deep eutectic solvents (DESs). The improvements in functionalizing adsorbents employing DESs for water treatment, such as removal of micropollutants, dyes, heavy metals, and other organic and inorganic contaminants from aqueous systems, are highlighted in this review. We describe the base materials employed for DES-based synthesis and functionalization of adsorbents as well as their physicochemical characteristics and water treatment applications (target chemicals and removal efficiency). The majority of the DESs significantly improved the removal of pollutants by increasing effective surface area and introducing desired functionalities. DESs were applied either during or after the production of adsorbent materials.