Recovery of gold from electronic waste by the synthesis of Pinus Brutia tannin polymer

Electrical and electronic waste (e-waste) is one of the most common waste problems today and contains many recyclable materials such as gold and palladium. In this study, an adsorption material was prepared by reacting tannin from Pinus Brutia bark with formaldehyde to recover gold from e-waste. The produced Pinus Brutia tannin (PBTR) polymer was characterized using TGA, BET, and FTIR. The adsorption efficiency was investigated using solutions containing gold ions with different pH values, adsorbent masses, initial concentrations, times, and temperatures. The results of these experiments were used to perform adsorption isotherm, kinetics, and thermodynamics calculations. The pseudo-second-order kinetic equation and the Langmuir isothermal equation were found to fit the experimental data best. The Au(III) ion saturation capacity of the PBTR particle monolayer was calculated to be 1771.73 mg/g at 328 K using the Langmuir isotherm. XRD and XPS analyses showed that most of the Au(III) ions were reduced to metallic gold after adsorption on the surface of the PBTR particles. Observations show that the adsorbent effectively removes Au(III) from the leaching solution generated by e-waste.