Selective recovery of Au(III) from aqueous solutions using 2-aminothiazole functionalized corn bract as low-cost bioadsorbent

A bioadsorbent was synthesized by modifying corn bract with 2-aminothiazole for the selective recovery of gold. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the bioadsorbent with the aim of understanding the mechanism of adsorption. Adsorption isotherms and kinetics data were determined and modeled. The adsorption capacity of Au(III) was 1668 mg/g, much higher than the values reported in the literature due to the ion exchange and chelation between the amino/thiol groups and Au(III). Additionally, the effect of pH and other ions on the Au(III) adsorption capacity were assessed. The adsorption isotherm was found to be consistent with the Langmuir isotherm model, and the kinetic was consistent with the pseudo-second-order kinetic model. Further regeneration and cyclic adsorption tests were performed to ensure the effectiveness of the bioadsorbent in commercial applications.