Eco-Friendly Porous Biocomposites Based on Cellulose Nanocrystalline Hydrogels: Development and Application to the Elimination of Removal of Methyl Red Dye in Aqueous Solutions

Cellulose nanocrystals (CNCs) which were extracted from industrial cotton waste was used to develop a new eco-friendly porous biocomposite sorbent based on cellulose nanocrystalline hydrogels (PCCNCsH). These new Nanocrystalline cellulose gelled beads is of interest in water purification technologies due to their high specific surface areas, excellent mechanical properties, biodegradability and non-toxicity. After bleaching, alkali and acid treatments of industrial waste cotton, the colloidal suspension of cellulose was freeze-dried for 24 hours to produce a white nanocrystalline cellulose powder. The obtained CNCs were immobilized in sodium alginate (NaAlg) gels to develop a new class of porous gelled biocomposite beads. Fourier Transform Infrared Spectroscopy (FTIR) as well as X-Ray Diffraction (XRD) analysis were used to characterize these novel porous hybrid sorbents. PCCNCsH were used as sorbents to remove methyl red (MR) batch wise and in aqueous solutions. The corresponding tests were conducted by examining the effects of sorbent dose, contact time, pH and initial dye concentration. The maximum sorption capacities of MR on the porous biocomposite based on cellulose nanocrystalline hydrogels was 21 mg/g for the optimum conditions were pH = 2, initial concentration of dye = 10 mg/L, contact time = 250 min and PCCNCsH dose = 0.2 (w/w). The kinetic sorption of methyl red on PCCNCsH sorbent best followed the pseudo-second order (PSO). The modeling of obtained sorption isotherms showed an appropriate fit for Langmuir model since the sorption isotherms are very closely (R² = 0.977).