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Irradiation resistance is important for adsorbents used in radioactive environments such as high-level liquid waste. In this work, a silica-based composite adsorbent (KAlFe(CN)6/SiO2) was synthesized and γ-irradiated from 10 to 1000 kGy. The angles of the main X-ray diffraction peaks slightly decreased with the increase in irradiation dose, and a minor decomposition of CN− occurred after irradiation to 1000 kGy, indicating that the KAlFe(CN)6/SiO2 adsorbent could preserve structural integrity with a dose below 100 kGy. In 1 to 7 M HNO3, the adsorption ability of the irradiated KAlFe(CN)6/SiO2 remained performant, with a higher Kd than 1625 cm3 g−1. The adsorption equilibrium of Pd(II) in 3 M HNO3 was attained within 45 min before and after irradiation. The maximal adsorption capacity Qe of the irradiated KAlFe(CN)6/SiO2 on Pd(II) ranged from 45.1 to 48.1 mg g−1. A 1.2% relative drop in Qe was observed after 100 kGy irradiation, showing that γ-irradiation lower than 100 kGy insignificantly affected the adsorption capacity of KAlFe(CN)6/SiO2. Calculating and comparing the structures and free energies of different adsorption products via the density functional theory (DFT) method showed that KAlFe(CN)6/SiO2 was more inclined to completely adsorb Pd(II) and spontaneously generate Pd[AlFe(CN)6]2.

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Glass solidification is a favorable treatment method for high level liquid waste (HLLW) from spent fuel reprocessing in industrial application, and the presence of palladium (Pd) in HLLW may seriously affect the glass solidification process. Ferrocyanide with a perovskite-like face-centered cubic structure has strong adsorption affinity towards Pd. In this study, silica-based composite KMnFC/SiO2 was prepared by pore crystallization of potassium manganese ferrocyanide (KMnFC) into porous SiO2. A series of characterization of the synthesized adsorbent were carried out such as XRD, TG-DTA, and SEM-EDS. It was verified that the adsorbent was successfully prepared and it has good Microscopic structure along with element distribution. A series of adsorption experiments were carried out. The adsorption of Pd is not easily affected by the concentration of nitric acid, which shows good acid resistance. Through the adsorption isotherm and adsorption kinetic curve, it is proved that the adsorption process of Pd by KMnFC/SiO2 is chemical monolayer adsorption. The adsorbent has strong adsorption selectivity for Pd in multi-ionic solution. Under the condition of complete adsorption of Pd, the adsorption rate of the adsorbent for other elements except Ru is less than 20%.