Cellulose Nanocrystals Derived from Microcrystalline Cellulose for Selective Removal of Janus Green Azo Dye

Cellulose nanocrystals (CNCs) as a bio-based adsorbent material have been synthesized at mild temperature reaction conditions using acid hydrolysis of microcrystalline cellulose (MCC) by sulfuric acid. CNCs by a simple acid treatment become enriched with negatively charged surface functionalities and shows good adsorption capacity. The CNCs have been characterized by X-ray photoelectron spectroscopy, Fourier transform Infrared, X-ray diffraction spectroscopy, and thermogravimetric analysis for their chemical composition, functionality, crystallinity, and stability, respectively. Sulfated CNCs have been used to selectively remove the toxic Janus Green (JG) dye tested out of many other dyes via adsorption and showed a Langmuir adsorption capacity of ∼77 mg g. -1 The effects of pH, temperature, concentration, and loading capacity have also been explored. The adsorption kinetics follows the pseudo-second-order pathway and thermodynamic analysis of the system indicates that the process is exothermic and spontaneous. Moreover, for the practical applicability of the proposed method, the adsorption of JG was also analyzed in four spiked industrial samples collected from nearby textile industries, where they removed more than 80% of the dye from the complex industrial water system.