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With the rapid development of nuclear energy, the contamination of environmental water systems by uranium has become a significant threat to human health. To efficiently remove uranium from these systems, three types of silica-based polyamine resins—SiPMA-DETA (SiPMA: silica/poly methyl acrylate; DETA: diethylenetriamine), SiPMA-TETA (TETA: triethylenetetramine), and SiPMA-TEPA (TEPA: tetraethylenepentamine)—were successfully prepared, characterized, and evaluated in batch experiments. Characterization results showed that the silica-based polyamine resins were successfully prepared, and they exhibited a uniform shape and high specific surface area. SiPMA-DETA, SiPMA-TETA, and SiPMA-TEPA had nitrogen contents of 4.08%, 3.72%, and 4.26%, respectively. Batch experiments indicated that these adsorbents could efficiently remove uranium from aqueous solutions with a pH of 5–9. The adsorption kinetics of U(VI) were consistent with the pseudo-second-order model, indicating that the adsorption process was chemisorption and that adsorption equilibrium was achieved within 10 min. SiPMA-TEPA, with the longest polyamine chain, exhibited the highest adsorption capacity (>198.95 mg/g), while SiPMA-DETA, with the shortest polyamine chain, demonstrated the highest U(VI) adsorption efficiency (83%) with 100 mM Na2SO4. SiPMA-TEPA still removed over 90% of U(VI) from river water and tap water. The spectral analysis revealed that the N-containing functional groups on the ligand were bound to anionic uranium–carbonate species and possibly contributed to the adsorption efficiency. In general, this work presents three effective adsorbents for removing uranium from environmental water systems and thus significantly contributes to the field of environmental protection. [ABSTRACT FROM AUTHOR]

The development of lithium–sulfur (Li─S) batteries has been hampered by the shuttling effect of lithium polysulfides (LiPSs). An effective method to address this issue is to use an electrocatalyst to accelerate the catalytic conversion of LiPSs. In this study, heterogeneous MnP‐MnO2 nanoparticles are uniformly synthesized and embedded in porous carbon (MnP‐MnO2/C) as core catalysts to improve the reaction kinetics of LiPSs. In situ characterization and density functional theory (DFT) calculations confirm that the MnP‐MnO2 heterostructure undergo surface sulfidation during the charge/discharge process, forming the MnS2 phase. Surface sulfidation of the MnP‐MnO2 heterostructure catalyst significantly accelerated the SRR and Li2S activation, effectively inhibiting the LiPSs shuttling effect. Consequently, the MnP‐MnO2/C@S cathode achieves outstanding rate performance (10 C, 500 mAh g−1) and ultrahigh cycling stability (0.017% decay rate per cycle for 2000 cycles at 5 C). A pouch cell with MnP‐MnO2/C@S cathode delivers a high energy density of 429 Wh kg−1. This study may provide a new approach to investigating the surface sulfidation of electrocatalysts, which is valuable for advancing high‐energy‐density Li−S batteries. [ABSTRACT FROM AUTHOR]

Successive grafting of new sorbent bearing amino phosphonic groups based on chitosan nano magnetite particles was performed through successive coupling with formaldehyde. The produced composite was characterized by the high sorption capacity toward rare earth elements (REEs) and consists of different types of functional groups (phosphonic, hydroxyls and amine groups) that are used for enhancing the sorption properties. The chemical modification and the sorption mechanism were investigated through different analytical tools; i.e., FTIR, SEM, SEM-EDX, TGA, BET (surface area) and pHpzc. The sorption was investigated toward Nd(III) as one of the REE(III) members under ultraviolet (UV) and visible light (VL) conditions. The optimum sorption was found at pH0 4 and the sorption capacity was recorded at 0.871 and 0.779 mmol Nd g−1 under UV and VL respectively. Sorption isotherms and uptake kinetics were fitted by Langmuir and Sips and by pseudo-first order rate equation (PFORE) for the functionalized sorbent, respectively. The sorbent showed a relatively high-speed sorption kinetic (20 min). The bounded metal ions were progressively eluted using 0.2 M HCl solution with a desorption rate 10–15 min, while the loss in the total capacity after a series of sorption recycling (sorption/desorption) (five cycles) was limited (around 3%) with 100% of the desorption efficiency, indicating the high stability of the sorbent toward an acidic medium. The sorbent was used for the recovery of REEs from leach liquor residue after pretreatment for the extraction of particular elements. From these results (high loading capacity, high selectivity and high stability against acid treatments), we can see that the sorbent is a promising tool for the selective recovery of rare earth elements in the field of metal valorization. [ABSTRACT FROM AUTHOR]

Scandium (Sc), a rare earth element, generally lacks independent large-scale deposits and is mainly recovered as a by-product in mineral processing. Herein, we systematically investigated the extraction of Sc by trialkyl phosphine oxide (TRPO) from both a scandium sulfate solution and leaching solution of Sc concentrate generated from titanium white waste acid in the sulfuric medium. The results showed that the optimum extraction conditions of Sc from scandium sulfate by TRPO were as follows: 10% TRPO, 5 mol/L H 2 SO 4 , and an A/O ratio of 1 for 20 min. The equation of scandium extraction by TRPO was calculated based on the log[c(TRPO)] - log[D] fitting results coupled with Fourier transform infrared spectroscopy (FT-IR) analysis, to which the extracted complex was deduced to be HSc(SO 4) 2 •2TRPO. Furthermore, for Sc extraction from leaching solution of its concentrate from titanium white waste acid, a relatively high extraction rate of up to 95.5% was obtained on the conditions of 20% TRPO, 7 mol/L H 2 SO 4 , 0.5% of H 2 O 2 , and at an A/O ratio of 10. Stripping with H 2 C 2 O 4 produced a high stripping rate of 99.9%, and the extraction and stripping system still presented excellent extraction performances even after five treatment cycles. Through the subsequent calcination of the stripped Sc 2 (C 2 O 4) 3 at 1000 °C for 2 h, we obtained the final product of Sc 2 O 3 with a high purity of over 99.34% with a total recovery yield of Sc as high as 95% in the whole process. Our findings contribute novel insights into the extraction and purification of Sc for its recovery from the secondary wastes. Unlabelled Image • TRPO was used to purify Sc from high acidity leaching solution of its concentrate. • 0.5% of H 2 O 2 was added into the feed solution to inhibit the extraction of Ti. • 0.4 mol/L H 2 C 2 O 4 can effectively strip Sc with a stripping rate of 99.9%. • TRPO is a potential extractant that can be reused at least five times. • A simple flowsheet for Sc purification was proposed and 99.34% Sc 2 O 3 was obtained with the yield over 95%. [ABSTRACT FROM AUTHOR]

The development of lithium-sulfur (Li─S) batteries has been hampered by the shuttling effect of lithium polysulfides (LiPSs). An effective method to address this issue is to use an electrocatalyst to accelerate the catalytic conversion of LiPSs. In this study, heterogeneous MnP-MnO 2 nanoparticles are uniformly synthesized and embedded in porous carbon (MnP-MnO 2 /C) as core catalysts to improve the reaction kinetics of LiPSs. In situ characterization and density functional theory (DFT) calculations confirm that the MnP-MnO 2 heterostructure undergo surface sulfidation during the charge/discharge process, forming the MnS 2 phase. Surface sulfidation of the MnP-MnO 2 heterostructure catalyst significantly accelerated the SRR and Li 2 S activation, effectively inhibiting the LiPSs shuttling effect. Consequently, the MnP-MnO 2 /C@S cathode achieves outstanding rate performance (10 C, 500 mAh g -1 ) and ultrahigh cycling stability (0.017% decay rate per cycle for 2000 cycles at 5 C). A pouch cell with MnP-MnO 2 /C@S cathode delivers a high energy density of 429 Wh kg -1 . This study may provide a new approach to investigating the surface sulfidation of electrocatalysts, which is valuable for advancing high-energy-density Li-S batteries., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)