Activated carbon/polyacrylamide-cl-xanthan gum nanocomposite for adsorption of methylene blue dye

The increasing discharge of synthetic dyes into aquatic environments has become a primary environmental concern because of their toxic nature, high chemical stability, and resistance to conventional treatment methods. This study presents the development of an innovative biodegradable nanocomposite (AC/PAAm-cl-XG) synthesized by integrating activated carbon (AC), polyacrylamide (PAAm), and xanthan gum (XG) into a multifunctional structure. The synergistic combination of AC's high surface area, PAAm's structural stability, and XG's biocompatibility and functional groups resulted in enhanced adsorption performance and environmental compatibility. Comprehensive characterization using XRD, FTIR, SEM, TGA, and BET analysis verified successful synthesis and desirable surface properties of the nanocomposite. The batch adsorption experiments were carried out to assess how different parameters like pH (3-9), adsorbent dosage (10-50 mg), initial dye concentration (10-100 mg/L), contact time (0-240 min), and temperature (25-55 °C) influenced adsorption performance. The adsorption followed the Langmuir isotherm model, indicating monolayer adsorption, with a maximum capacity of 1094.2 mg/g, surpassing many previously reported AC and XG-based adsorbents. Kinetic analysis revealed that the adsorption process adhered to the pseudo-second-order model, suggesting that chemisorption played a dominant role. The evaluation of thermodynamic parameters indicated that adsorption was both spontaneous and exothermic. The nanocomposite exhibited strong reusability, maintaining 81.46 % of its dye removal efficiency after four consecutive cycles. Overall, the findings highlight AC/PAAm-cl-XG nanocomposite as a biodegradable, economical, and efficient adsorbent with significant potential for dye removal, supporting the development of sustainable water treatment solutions.