Jute fiber-derived functional cellulose nanocrystals for efficient methylene blue dye adsorption

Adsorption has become the most familiar approach for removing dye from textile effluent. Achieving high dye removal efficiency via inexpensive, sustainable adsorbents is a common dilemma. In recent years, highly functional cellulose nanoparticles have been a promising candidate for dye adsorption. This study employed functional cellulose nanocrystals (FCNCs), isolated from jute fiber using the oxidization method, as an adsorbent to remove methylene blue (MB) from an aqueous solution. The different characteristics of FCNCs were analyzed with thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The FTIR analysis revealed that the oxidation of jute fiber by ammonium persulfate (APS) produced a carbonyl peak at 1730 cm^-1. The TGA study showed a single peak between 305 °C and 318 °C, indicating good thermal properties. The XRD graph demonstrated FCNCs were highly crystalline, with a crystallinity index of 70%. The impacts of pH, temperature, and initial dye concentration were explored to maximize the amount of dye adsorption. The adsorption equilibrium data was analyzed with the Langmuir and Freundlich isotherm models; however, the Langmuir model provided a more accurate description of the adsorption procedure. The highest possible adsorption capability at room temperature and unadjusted pH (pH = 6.4) was 1566.95 mg dye per g FCNCs. This result suggests that FCNCs are apparently an effective adsorbent for removing cationic dyes.