Immobilization of ionic liquids onto chloromethylated polystyrene as a strategy for highly efficient and selective recovery of Au(III) from gold slag and PCBs

The recovery of Au(III) has become a focal point of interest due to its significance in resource utilization and addressing environmental contamination. In this study, [C3NH2Mim]Cl-CMPS and PPh3-CMPS were successfully developed by immobilizing [C3NH2Mim]Cl and triphenylphosphine (PPh3) onto chloromethylated polystyrene beads (CMPS). The adsorbents demonstrated consistently high adsorption efficiency (>95 %) at a wide pH range. The [C3NH2Mim]Cl-CMPS and PPh3-CMPS exhibited exceptional selective adsorption ability for Au(III), and the adsorption process adhered to the PSO and Langmuir model. The adsorption efficiency of Au(III) remained constant after five consecutive cycles, highlighting outstanding reusability performance. Furthermore, as the existence of multiple coexisting metal ions, [C3NH2Mim]Cl-CMPS and PPh3-CMPS could efficiently and selectively capture Au(III) from the gold slag and PCBs lixivium, which is promising for Au recovery in practice.