Adsorption behavior of Crys tal Violet dye in aqueous solution using Co+2 hectorite composite as adsorbent surface

This study focused on the adsorption behavior of the cationic CrystalViolet (CV) dye from aqueous solutions using a Co+2‒hectoritecomposite as an adsorbent surface. The initial and equilibrium CV dyeconcentrations were determined using a UV-Vis spectrophotometer. Theresults were discussed and presented for the impacts of pH, primary CVdye concentration, composite dosage, and temperature. The optimumconditions were found for eliminating Crys tal Violet dye from theaqueous solution at a pH 4, ideal temperature 293 K, and 0.5 g L-1 of composite dose. The pseudo-second-order kinetic, intraparticlediffusion analyzed the tes ts’ data and film diffusion models. Eachmodel’s defining features have been identified, and these models werein good agreement and in charge of regulating the adsorption reaction.The adsorption operation was also thermodynamically examined todetermine thermodynamic variables such as Gibbs free energy (ΔG°),entropy (ΔS°), activation energy (Ea), and enthalpy (ΔH°). The negativevalue of Gibbs free energy (ΔG°) and enthalpy (ΔH°) indicated thatthe adsorption process was a spontaneous and exothermic reaction.While the activation energy (Ea) data which fell within the normalrange for physisorption, was showed at  22.434 kJ mol-1. This result proved that physical adsorption occurs between the CV dye and the adsorbent surface (Co+2‒hectorite composite)