Biogenic Synthesis of Cr‐Doped NiO/Clay Composite for Improved Dye Removal and CO ₂ Capture Studies

Abstract The current work was designed to eliminate reactive yellow 18 dye (RY‐18) via adsorption from water, and CO 2 from the gas stream, using the tragacanth gum‐based Cr doped NiO N.P.s/Clay (GCNC) composite. The one‐pot synthesis approach was used to produce the adsorbent, and physical and chemical properties were assessed using techniques like XRD, FTIR, UV‐visible spectroscopy, SEM, DLS, Zeta Potential, and adsorption–desorption isotherm. The GCNC composite demonstrated an impressive adsorption potential and percentage removal of 398 mg/g and 91.28%, respectively. Temkin and intraparticle diffusion models with R 2 values of 0.98401 and 0.99918 were the most effective at fitting the experimental adsorption model. The thermodynamics parameters, including the change in enthalpy ( H ), entropy ( S ), and Gibbs free energy ( G ), demonstrated the endothermic and spontaneous nature of the adsorption process. A positive H value indicates an endothermic process, while a negative G value indicates a spontaneous process. According to the isotherms fitting model, the capacity for adsorbing CO 2 at 25 °C and 1 atm was 4.8 mmol/g. The significant correlation between the slope in the log‐linear plot of the isosteric heat of adsorption and CO 2 adsorption performance indicates that the isosteric heat of adsorption can be used as a predictive tool for CO 2 adsorption performance. These significant results underscore the potential of the GCNC composite to revolutionize the water treatment field and CO 2 capture, offering hope for a more sustainable and cleaner future.