Theoretical study on the extraction behaviors of MoO22+ with organophosphorous extractants

An insightful study on the reduction and extraction of neptunium assisted by molybdenum

High-level liquid waste (HLLW) generated through nuclear reactions and spent fuel reprocessing contains the critical transuranic element neptunium (Np). Thus, the efficient recovery of Np from HLLW via the TRPO (trialkylphosphine oxide) process is not only beneficial for radioactive contamination remediation but also boosts the recycling of precious nuclear resources. However, this process including Np(V)-Np(IV) conversion is highly dependent on the components coexisting in HLLW, and its underlying mechanism is still not clear, restricting the recovery of Np in multiple scenarios. Herein, the effect of coexisting metal ions on the reduction and extraction of Np(V) was studied, and molybdenum (Mo) was identified to play a vital role in this course. Additionally, in combination with absorption spectral analysis, X-ray photoelectron spectroscopy and solvent extraction, the promotion of the extraction of Np by Mo was elucidated to be due to the catalytic reduction effect both in the aqueous phase and organic phase. This study can help researchers better understand the redox chemistry of Np in the treatment of HLLW.

Extraction of Palladium(II) with a Magnetic Sorbent Based on Polyvinyl Alcohol Gel, Metallic Iron, and an Environmentally Friendly Polydentate Phosphazene-Containing Extractant

In this work, a highly efficient and environmentally friendly method for extracting palladium from hydrochloric acid media was developed. The method uses a magnetic sorbent carrying an organophosphorus extractant, which is not washed from the sorbent into the aqueous phase. The extractant was characterized by 1H, 13C, and 31P NMR spectroscopy and MALDI TOF mass spectrometry, and the palladium complex based on it was characterized by IR spectroscopy. According to an in vitro microbiological study, the extractant was non-toxic to soil microflora. It was established that the water uptake and saturation magnetization of the magnetic sorbent were sufficient for use in sorption processes. The sorption efficiency of palladium(II) with the developed sorbent can reach 71% in one cycle. After treatment of the spent sorbent with 5 M hydrochloric acid, palladium was completely extracted from the sorbent. The new sorbent is proposed for the extraction of palladium from hydrochloric acid media obtained by the leaching of electronic waste.