High performance and selectivity recovery of Au(III) from waste solution using the RFU resin

Designing and synthesizing high activity adsorption materials for recycling precious metals is essential to meeting the needs of the high-tech industry. Here, a new adsorbent material RFU is prepared by grafting urea onto the phenolic resin by one-step hydrothermal synthesis method. It has been proved that RFU microspheres had extremely high absorption capacity and excellent selectivity (the adsorption capacity can reach 1600 mg/g when the initial concentration of Au(III) is 1 g/L) for Au(III). Different factors affecting the adsorption process such as pH, adsorption capacity, selectivity, contact time, and reusability were systematically investigated. FT-IR, SEM, TEM and XPS were used to characterize the adsorbent before and after adsorption. 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 indicate that RFU can be recycled at least four times. Combining its characterization with kinetic and thermodynamic data, we drew the conclusion that N-H and C = O of RFU played an important part during adsorption. The strong soft-soft interaction between N, O atoms and Au atoms gives the material excellent gold ion adsorption capacity and adsorption selectivity. These findings can broaden the path for the use of nitrogen-rich nanomaterials in gold ion recovery.