Nanshan Group (China)

Polymer fibers that have the most industrial potential for uranium enrichment in seawater suffer from low adsorption site utilization because the polymer chains are often entangled due to intra-molecular interactions. Herein, a branched-linear intertwining electrospun fiber (PAN-bPEI-T/PVA) is obtained by co-grafting hyperbranched polyethyleneimine (bPEI) and linear triethylenetetramine (TEPA) for harvesting uranium from seawater. The fiber features a dendritic topology structure with a high density of distributed amino functional groups, which provide extensive pathways for uranium transport and contact. Meanwhile, the linear TEPA modulates the hydrogen bonding network by converting the strong intramolecular hydrogen bonds in bPEI into intermolecular hydrogen bonds, thereby enhancing the permeability and exposing more active sites. Compared to conventional bPEI polymer, the PAN-bPEI-T/PVA demonstrates higher accessibility and utilization of sites, achieving a capacity up to 806.4mg g-1 in uranium-spiked seawater, surpassing that of bPEI fiber by 2.5 times. The fiber retains over 95% capacity even after 7 cycles, demonstrating excellent reusability. Quantum-theoretical studies reveal that the flexible TEPA can form a synergistic adsorption network with bPEI, which undergoes adaptive adjustment in seawater to capture uranyl, improving both uranium uptake and selectivity. The proposed underlying mechanism of branched-linear intertwining provides a practical approach for designing high-performance uranium adsorbents.

Commercial separators face significant challenges in mitigating lithium dendrite growth, primarily due to non-uniform lithium ion deposition, which leads to battery performance degradation and raises safety concerns related to separator failure. To address these issues, this study proposes a novel composite separator incorporating two-dimensional (2D) X-type molecular sieves as a functional coating for lithium metal battery separators. The primary objective is to achieve uniform lithium-ion distribution across the surface of the lithium metal anode, thereby effectively inhibiting the formation of lithium dendrites. The results indicate that in comparison to conventional polypropylene (PP) separators, the 2D-X-PP composite separators exhibit substantially improved physical properties, such as enhanced thermal stability, wettability, and tensile strength. In terms of electrochemical performance, cells incorporating the 2D-X-PP separators retained an outstanding 70% of their initial capacity after 1000 cycles, while those employing PP separators retained less than 50% of their capacity after only 500 cycles. These findings provide strong evidence of the exceptional performance of 2D-X-PP and further pave the way for the development of molecular-sieve-functionalized separators in lithium metal batteries.

Nitrogen (N) fertilization is a major contributor to yield, quality and environmental impact in rice production. Conceptually, high level of N application is viewed as associated with high yield, inferior quality and high environmental cost. However, very few studies have investigated how yield, eating quality and protein content respond to N application levels under field conditions, especially with regards to rice varieties of different genotypes for genes specifying nitrogen utilization efficiency (NUE). In this study, we conducted field experiments in Hubei (south) and Heilongjiang (north) Provinces, with four different N fertilizer levels in each site. The south site included 11 indica and 3 japonica varieties, and the north site involved 9 japonica varieties. The results showed that for most varieties, yield increased linearly in response to N application from N0 (0N fertilizer) to N100 (100kg·ha-1), with no significant further increase, on average, at higher N levels. Notably, significant varietal differences were observed, with a few high-performing varieties sustaining yield increases even at the highest N rate. While the protein content in grain (GPC) was linearly associated with N application levels up to N200 in indica varieties, the response was not linear in japonica varieties where GPC decreased from N0 to N50, and slightly increased from N50 to N100 and further slightly increased at N150. The taste values of the indica varieties showed significant negative association with the N levels showing lowest taste values at the highest N level. There was a significant increase in taste values of the japonica varieties from N0 to N50 and N100, but decrease at N150. Overall, there was a highly significant negative correlation between taste values and GPC. While a moderate level of N fertilization can simultaneously optimize yield and taste value of japonica in the north, no such optimal level could be found for indica varieties. We genotyped 11 GPC and NUE genes of these varieties, and found that indica varieties carried the high GPC and NUE alleles at almost all the loci while the reverse was the case for the japonica varieties, which was corresponded to differential phenotypic responsiveness. Consequently, indica varieties exhibited higher variation in yield and quality traits in response to nitrogen, while japonica varieties showed more attenuated responses. Furthermore, high N application (N200) reduced the contents of P, K, Mg, Mn, and Zn and increased the contents of Cd, and Hg in the indica rice grains in the south site. Taken together, N fertilization at a rate ~ 100kg·ha-1 may provide a rational practice balancing yield and quality in rice production under the experimental field conditions.

Silk sericin (SS) hydrogels are attractive for soft-matter applications due to their natural origin, ease of processing, and superior hydrophilicity, yet their poor compressibility and structural stability remain key limitations. Here, we report a facile and scalable route for producing highly compressible ionic hydrogels by covalently grafting glycidyl methacrylate (GMA) onto SS (SS-g-GMA). The grafting density can be tuned between 81.26 % and 98.86 % simply by adjusting temperature and GMA dosage, yielding a UV-curable precursor that maintains excellent rheological properties. Photopolymerization generates a uniform, interconnected microporous network with pore sizes of average 27.24 μm pores, which imparts the hydrogel with an exceptional compressive stress of 70.03 kPa at 67.09 % strain and an ionic conductivity of 0.15 S m −1 . The recombination of hydrogen bonds facilitates rapid electrical self-healing (93.21 % recovery within 15 s). The stress-dependent resistance changes exhibit linear characteristics, rendering this compressible ionic hydrogel suitable for applications in stretchable electronics, biomedical scaffolds, and soft actuators. • Silk sericin hydrogel comprise microporous network were fabricated. • The grafting density can be tuned by adjusting temperature and GMA dosage. • The UV-curable precursor that retains excellent rheological properties. • Hydrogel with exceptional compressive stress at strain and an ionic conductivity. • The hydrogel demonstrates self-healing and is suitable for diverse applications.

Ion exchange resins are commonly utilized for treating liquid radioactive waste within nuclear power plants; however, the disposal of these waste resins presents a new challenge. In this study, magnesium silicate hydrate cement (MSHC) was used to immobilize the waste resin, and the immobilization effectiveness of the MSHC-solidified body were assessed by mechanical properties, durability, and leaching performance. Hydration heat, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electronic microscopy (SEM), and mercury intrusion porosimetry (MIP) were used to study the hydration process of the MSHC-solidified body containing Cs+, Sr2+, and Cs+/Sr2+ waste resins. The results demonstrated that the presence of waste resins slightly delayed the hydration reaction process of MSHC and reduced the polymerization degree of the M-S-H gel, and the composition of the hydration products were not changed. The immobilization mechanism for radionuclide ions in resin included both mechanical encapsulation and surface adsorption, and the leaching of Cs+ and Sr2+ from MSHC-solidified body followed the FRDIM. When the content of the waste resin was 25%, the MSHC-solidified body exhibited satisfactory compressive strength, freeze-thaw resistance, soaking resistance, and impact resistance. These results strongly indicated that MSHC possessed the ability to effectively immobilize ion exchange resins.