Adsorption of Methylene Blue over CuS/ZrS₂ Nanocomposite Prepared by Precipitation Method: Thermodynamic and Kinetic Study

CuS/ZrS2 nanocomposites were prepared by precipitation method. A number of techniques for nanoparticle characterization were used, including X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, UV-Vis, and FTIR techniques. The characterization revealed the presence of CuS /ZrS2 composite. The field emission scanning electron microscopy (FESEM) and the manufactured product was examined CuS/ZrS2 -30, CuS/ZrS2-90 particle sizes have been found 27.64 nm and 24.96 nm, respectively. The XRD patterns of CuS/ZrS2 nanocomposite, it was discovered that ZrS2/CuS-30, CuS/ZrS2-90 nanoparticles had a pattern of 8.92 nm and 10.04 nm, respectively. The band gap energy value for the nanoparticles was estimated to be (1.7 eV and 2.1 eV). Finally, the removal of methylene blue by CuS/ZrS2 nanocomposite from aqueous solution was investigated in the present study. The adsorption kinetics was examined using pseudo-first-order, pseudo-second-order and intra-particle diffusion model. The equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherm models. The results revealed that the pseudo-second-order model and Langmuir isotherm fit the kinetics and equilibrium data, respectively. In addition, various thermodynamic parameters, such as change in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS), were also calculated. The thermodynamic analysis showed that the adsorption of MB was spontaneous and exothermic.