Preparation of an injectable hydrogel reinforced by graphene oxide and its application in dye wastewater treatment

An injectable hydrogel based on poly(N-isopropylacrylamide) and carboxymethyl cellulose, reinforced with GO was successfully prepared by in situ generation of hydrazone bonds, and was employed to treat cationic dye wastewater through adsorption. The incorporation of GO significantly improved the mechanical strength and shortened the gelation time of the hydrogel, as well as the cooperative effect with the hydrogel matrix for the absorption of methylene blue (MB) dyes. The hydrogel could achieve effective removal of MB dye from aqueous solution. Adsorption capacity was determined 601.7 mg/g and 1622.1 mg/g with removal efficiency of 90.4% and 60.4%, at high concentrated MB solution of 500 mg/L and 2000 mg/L, respectively. The factors that affect the dye adsorption performance including the adsorbent dosage, solution pH and initial dye concentration were studied. The kinetic and isotherm equilibrium data were well fitted by the Pseudo-second-order and Langmuir models, respectively, and the hydrogel adsorbent showed remarkable reusability. The mechanism analysis revealed that ion exchange, chemical adsorption, electrostatic interaction and pi-pi stacking may control the adsorption process. Overall, this work provided a rapid, viable route to fabricate injectable hydrogels for efficient application in wastewater treatment.