Fabrication of a novel bio-polymer adsorbent with high adsorptive capacity towards organic dyes

A novel adsorbent, CMC-T-CH, was fabricated by crosslinking of carboxymethyl cellulose (CMC) and chitosan (CH) with triethylenetetramine. The adsorbent's efficacy in removing the hazardous dyes, Direct blue (DB) and Congo red (CR), was investigated. Different physical, chemical, and biological methods have been employed to eliminate CR and DB dyes from aqueous solution, and adsorption has shown potential in eradicating these dyes effectively. Various characterization methods were employed to investigate the physicochemical characteristics of CMC-T-CH. The removal process was performed at optimized conditions of pH 6 for CR and pH 5 for DB at the temperature of 35 °C, resulting in maximum removal efficiencies of 99 % and 98.33 % for CR and DB, respectively. Langmuir isotherm and pseudo-second-order kinetic mathematical models were utilised to analysed the interaction of adsorbate and adsorbent during the removal process. The maximum theoretical adsorptive capacities of 519.53 and 534.25 mg/g were achieved for CR and DB removal, respectively. The regeneration study revealed that the dye-loaded CMC-T-CH could be reused several times. The phytotoxicity assay showed that the germination of Vigna mungo seeds improved after the removal treatment, thus confirming the potential of CMC-T-CH in the elimination of CR and DB.