Preparation of a mesoporous ion-exchange resin for efficient separation of palladium from simulated electroplating wastewater

Palladium, as a member of platinum group metals, has very little reserve in nature. It usually plays a role in corrosion resistance in the electroplating industry, and is easily discharged into electroplating wastewater during processing. Therefore, it is of great significance to develop efficient functional materials which can rapidly and selectively capture Pd(II). Herein, a mesoporous ion exchange resin (SiAaC) based on a silica framework was designed and synthesized by in situ polymerization method to efficiently remove Pd(II) from simulated electroplating wastewater. SiAaC exhibited unique advantages over traditional commercial resins, such as high adsorption capacity (121.8 mg/g), high selectivity (SFPd/M>230 in 0.01 M HNO3 solution) and excellent reusability (n > 5). The adsorption results of SiAaC resin on Pd(II) are consistent with Langmuir isotherm and pseudo-second-order kinetic models. In addition, the column experiment can efficiently separate Pd(II) from simulated electroplating wastewater. Furthermore, FT-IR and XPS spectra proved an ion exchange mechanism between SiAaC and Pd(II). In general, this research not only demonstrated an excellent material which can effectively and efficiently remove low-level palladium from simulated electroplating wastewater, but also provided a new perspective for the synthesis or improvement of ion exchange resins.