Efficient Removal of Au(III) using Nano-Sulfurized Copper-Loaded Wood from Acidic Aqueous Solution

The design of green, efficient, and acid-resistant adsorbents is crucial for gold recovery from acidic leachates of secondary resources.In this study, a wood-based adsorbent loaded with nano-sulfurized copper exhibiting adsorption advantages in acidic environments was fabricated by loading copper sulfide nanoparticles onto delignified wood.This adsorbent exhibited excellent adsorption performance in acidic environments, with a maximum adsorption capacity of 750 mg/g achieved at pH 2.0.Adsorption equilibrium data were well fitted by the Langmuir isotherm model, while kinetic data conformed to the pseudo-second-order model.Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic.The adsorption mechanism of CuS/PW toward Au(III) was systematically investigated via X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS).Results demonstrated that in addition to S 2-in copper sulphide and hydroxyl groups in cellulose participating in the chelation and reduction of Au(III), carbonyl groups in hemicellulose and lignin also contribute to the chelation and reduction of Au(III).Collectively, this work not only develops an efficient and eco-friendly adsorbent for Au (III) removal from acidic aqueous solutions, but also provides a promising strategy for the design of biomass-based adsorbents in precious metal recovery.