Platinum (Pt) is a nonrenewable mineral with limited reserves and a patchy distribution. Pt demand and consumption are growing year after year. As a result, recovering Pt from the secondary resources is critical. A new strategy for effective Pt recovery employing Fe(III)-oxalate complexes under UV and visible light irradiation is proposed in this paper. This approach can recover 98.9% of Pt in 30 min under the conditions of 365 nm UV irradiation, leaching time = 30 min, C2O42– concentration = 333.33 g/L, and H2O2 addition = 0.60 vol %. More importantly, 95.6% of Pt can also be recovered in 8 h under sunlight. The homogeneous photocatalytic reaction is rapid and efficient, and meanwhile, no strong acid, base, or volatile toxic organic solvent is required. Additionally, the iron utilized in the process may be well-recycled, solving the problem of recovery difficulty of homogeneous photocatalysts and lowering the cost of leaching. Simultaneously, the Pt complex recovered from the waste catalyst is utilized in situ to manufacture 0.1 wt % Pt/ZSM-5 catalyst, which shows the complete conversion of toluene at 200 °C and can remain stable during the long duration reaction of 1200 min. Overall, it can not only provide a new environmentally friendly technique to recycle Pt from spent catalysts but also save manufacturing cost of new catalysts.
The efficient recycling of platinum (Pt) from proton exchange membrane fuel cell (PEMFC) catalysts is crucial due to Pt's scarcity and geopolitical constraints. However, existing approaches for selective Pt recovery from Pt-Co solutions face critical limitations: poor selectivity in multi-metal systems, narrow pH tolerance, and unclear adsorption mechanisms for Pt(IV)/Co(II) differentiation. To address these gaps, this study introduces two solvent-impregnated resins (SIRs)—N235/XAD-16 (amine-based) and Cyanex923/D101 (phosphine oxide-based)—for targeted Pt(IV) recovery from Pt-Co solutions. Through integrated experimental and density functional theory (DFT) analyses, we elucidate the distinct adsorption mechanisms underlying each SIR's Pt(IV)/Co(II) separation performance. N235/XAD-16 exhibits strong pH-dependent behavior, achieving 99.95 % Pt recovery at pH 1 via electrostatic interactions between protonated amine groups and PtCl 6 2− anions; however, its efficiency declines by ∼50 % at pH > 3 due to reduced protonation. In contrast, Cyanex923/D101 maintains >90 % Pt adsorption across pH 1–6, leveraging dual pathways: electrostatic attraction and coordination bonding forming stable [PtCl 4 (R 3 PO) 2 ] complexes. DFT calculations quantify stronger Pt-O bonding in Cyanex923 (Wiberg bond index: 0.56) versus Pt-N interactions in N235 (0.46), corroborated by FT-IR/XPS spectral shifts. Both resins demonstrate excellent reusability (>90 % Pt desorption over 3 cycles) and acid resistance (<8 % extractant loss in 4 mol/L HCl). Specifically, N235/XAD-16 exhibits more excellent separation performance under low pH conditions (<2), while Cyanex923/D101 maintains stable Pt adsorption across a broader pH range (1–6). This work establishes a structure-property framework for designing pH-resilient adsorbents, advancing sustainable Pt recovery from complex waste streams.
危险品化学品经营许可证（带存储）