Photochemical Separation of Platinum Group Metals in Aqueous Solution——Photoreduction of Pd（Ⅱ）

In present work, the photochemical method was proposed to reduce Pd（Ⅱ） ions in Na₂PdCl₄ aqueous solution, and the effects of various experimental parameters including the wavelength of light, radical scavengers, concentration of Cl^- and pH values were studied. The supernatant and precipitation products have been characterized by the UV-vis spectra and XPS respectively. The results indicate that Pd（Ⅱ） ions in aqueous solution can be extracted by the photoreduction method by a ratio of 98.4%, and the generation of Pd atoms is more efficient in the presence of 2-propanol than ethanol, methanol or tertiary butanol. High concentration Cl^- will suppress the reduction of Pd（Ⅱ）, and high pH value can enhance the reduction of Pd（Ⅱ）. In addition, the extraction of palladium metal from the mixed solution of Na₂PdCl₄ and NdCl₃ was also demonstrated.