Adsorptive Removal of Cationic Dye from Aqueous Solution by Graphene Oxide/Cellulose Acetate Composite

The application of graphene oxide in water treatment is facing a rigorous challenge of how to separate nanoadsorbents from aqueous solution using conventional methods after adsorption. Herein, a new type of easily separated composite was fabricated using cellulose acetate (CA) crosslinked with graphene oxide (CAGO) and a simple vacuum freeze-drying method. The CAGO composites were subject to SEM, FTIR, TGA, and BET characterizations. The adsorption performance of the adsorbent for the removal of methylene blue (MB) was evaluated through investigating the experimental parameters such as initial dye concentration, temperature, adsorbent dose, contact time, and solution pH. The Langmuir and Freundlich isotherm models were applied to fit the equilibrium data. The maximum adsorption capacity of methylene blue onto the CAGO-4 composite was 374.53 mg/g at 323 K. The kinetic data showed a good determination with pseudo-second-order equation. Thermodynamic analysis indicated that the adsorption was an endothermic and spontaneous process.