Fabrication of sodium alginate/graphene oxide/nanocrystalline cellulose scaffold for methylene blue adsorption: Kinetics and thermodynamics study

The development of environmentally friendly and highly efficient adsorbent materials is an important issue under study all the time all over the world. Herein, a robust 3D scaffold of sodium alginate/graphene oxide/ nanocrystalline cellulose (SA/GO/NC) was fabricated for the potential adsorption of methylene blue (MB) dye. First, NC was extracted from palm sheath fibers and graphene oxide was synthesized from graphite. Then the scaffold was fabricated from a lyophilized SA/GO/NC bio-nanocomposite via cross-linking treatment. The impact of NC content (10, 15, and 20%) on the chemical, physical, thermal, and mechanical properties of fabricated scaffolds was studied too. The physical properties, chemical structure, and surface morphology of SA/GO/NCs scaffolds were investigated by Brunauer-Emmett-Teller (BET), Attenuated total reflection infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA) instruments. The effect of pH, adsorbent dose, contact time, pseudo-first-order models, pseudo-second-order models, and thermodynamics on MB uptake was also studied. The obtained thermodynamic values (& UDelta;H, & UDelta;S, and & UDelta;G) indicate that the process is exothermic and spontaneous with physisorption mechanism directly dependent on the amount of NC used.