Hydrogen bonds-based flexible regulation of acetaminophen adsorption/desorption behavior in aqueous system: Role of the smart thermoresponsive graphene oxide

Adsorption and regeneration techniques are crucial for the treatment of pharmaceuticals in drinking water. However, adsorbents with strong adsorption binding force and simple regeneration have been a challenging issue in the adsorption area that has not been successfully resolved. In this study, a thermos-responsive smart adsorbent, poly (N-isopropylacrylamide) modified graphene oxide (GO-g-PNIPAM) was successfully synthesized using a “graft from” surface-initiated atom-transfer radical polymerization (Si-ATRP) technology. Acetaminophen (Acet) has an excellent efficient adsorption/desorption behavior (107.40/83.9 mg/g) that is potentially flexible controlled by the modified adsorbent only by adjusting the temperature. This exceptional property is primarily caused by the phenomenon that PNIPAM cooperated with GO to undergo hydrophilic transformation in response to temperature changes, allowing for the free construction and deconstruction of hydrogen bonds between PNIPAM and contaminants. More importantly, as external factors (NaCl and urea) are mediated, the development of hydrogen bonds would be further encouraged to further stabilized the efficiency, and the desorption temperature would continue decrease by 2 and 6 °C, respectively, to promote the regeneration process. This outstanding work provides novel perspectives for subsequent smart sensitive materials to flexibly regulate the treatment efficiency of pollutants.