Preparation of chitosan-based ternary nanocomposite hydrogel film by loading graphene oxide nanosheets as adsorbent for enhanced methylene blue dye removal

Our objective in this study is to fabricate a novel chitosan-based ternary nanocomposite hydrogel film by incorporating graphene oxide (GO) nanosheets into a chitosan/partially hydrolyzed polyacrylamide (PHPA) network to boost adsorption efficiency through one step self-assembly process in water. Basically, H-bonding interactions drive the formation of a crosslinking network structure. The Batch adsorption experiments evaluated the hydrogel nanocomposite's MB adsorption performance. By loading GO, surface roughness, swelling percentage (from 21,200 % to 35,800 %), elastic modulus of up to 73.7 Pa, and adsorption characteristics (from 282 mg/g to 468 mg/g) were enhanced. The nanocomposite displayed outstanding thermally/pH responsiveness properties. MB adsorption equilibrium was reached after 45 min and the adsorption capacity was 476.19 mg.g−1 when the initial concentration was 100 mg/L. The MB adsorption kinetics and isotherms by the nanocomposite were well correlated by the PSO and the Langmuir models (R2 > 0.99), respectively. The loaded nanocomposite was shown to be regenerative for five cycles through desorption studies. Thermodynamic analysis indicated that MB adsorption occurred spontaneously (ΔG°: −16.47 kJ/mol, 303 K) and exothermically (ΔH°: −79.49 kJ/mol). A plausible adsorption mechanism was proposed for the nanocomposite developed for MB removal. Our results can contribute to the design and fabrication of nanocomposite adsorbents to treat wastewater. •A novel adsorbent of self-assembled chitosan-based ternary nanocomposite hydrogel film for cationic dye capturing•Nanocomposite hydrogel was effective in MB removal with maximum adsorption of 468 mg/g.•MB adsorption data was well fitted by Langmuir isotherm and pseudo-second-order model.•The CS-based nanocomposite can be regenerated and reused in many cycles of adsorption with resilience.•Thermodynamic analysis indicated that MB adsorption occurred spontaneously and exothermically