Kinetics Thermodynamics and Equilibrium

This study investigates the recovery of gold from residual solutions of the electroplating industry using a copolymer sorbent, 2,2′-thiobisethanol dimethacrylate/ethylene glycol dimethacrylate (coP-TEDMA/EGDMA). The objective was to characterize the synthesized material and to elucidate the sorption process through kinetic, thermodynamic, and equilibrium studies. Various characterization techniques, including X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy, were employed to analyze the material. The sorption capacity was influenced by parameters such as pH, temperature, and initial gold concentration. Experimental data were modeled using Langmuir, Freundlich, and Sips isotherms, revealing that the Sips model best described the sorption process. Kinetic analyses identified that the pseudo-second-order model most accurately represented the process dynamics. Moreover, thermodynamic parameters, including free Gibbs energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), were calculated, demonstrating that the gold recovery process is spontaneous and endothermic. This comprehensive study provides valuable insights into the potential of coP-TEDMA/EGDMA as an effective sorbent for gold recovery, contributing to the sustainability of waste management in the electroplating industry.