旋带掩模电解织构化圆柱表面及其润湿性分析

在圆柱面工件上高效、低成本地创制功能化极端润湿性表面仍面临重大技术挑战。对此提出旋带掩模电解织构技术。该技术直接选用市售带状柔性电绝缘多孔高分子编织布为活动掩模，以中性盐Na NO3溶液为电解液，基于旋带电解印制方式对金属圆柱表面进行织构化处理。介绍其工作原理，分析圆柱表面微织构形貌与几何廓形的演化过程，试验探究极间电压、旋带速度、加工次数等对表面织构特征的影响，评测氟化后的不同微结构特征的织构化表面的润湿性。结果表明：圆柱表面织构特征显著受加工次数的影响，随加工次数的增加，圆柱表面经历“反复复制”掩模印制阵列凹凸微结构、阵列凹凸微结构叠错-细化、微纳米分级结构分级化等表面微织构化演化过程；用时仅需249 s制备的外径49 cm、长50 cm的SUS304圆柱面（氟化后）微-纳米分级结构表面对水/甘油/十六烷的接触角分别为160.4°、 158.5°、 153.6°、滚动角分别为2.1°、5.6°、8.6°；呈现优异的超双疏极端润湿性且机械耐久性好。旋带掩模电解织构技术在圆柱面工件制取机械耐久性极端润湿性功能表面方面呈现高效、低成本、便于实施等优势。     

Operando Forming of Lattice Vacancy Defect in Ultrathin Crumpled NiVW-Layered Metal Hydroxides Nanosheets for Valorization of Biomass

The 2D layered metal hydroxides (LMHs) have been developed for electrooxidation of 5-hydroxymethylfurfural (HMF). In this work, an effective strategy is proposed to tailor the electronic structure of active sites at the atomic level, which is by introducing defects into the lattice structure. As an example, a series of ultrathin crumpled ternary NiVW-LMH electrocatalysts with abundant lattice vacancies (denoted as NiVW_v-LMH) are prepared in this way. The introduction of tungsten (W) endows the catalyst with a special crumpled structure, which promotes the generation of lattice vacancies and thus exposes more unsaturated Ni activity sites. The NiVW_v-LMH displays superb performance in the electrooxidation of HMF. The Tafel slope for electrodehydrogenation of Ni²⁺ OH bond to Ni(OH)O species is 12.04 mV dec⁻¹. The current density at 1.43 V versus reversible hydrogen electrode (RHE) toward the oxidation reaction of HMF reaches about 193 mA cm⁻², which is better than most of the common electrocatalysts, with an 5.37-fold improvement compared with Ni(OH)₂ electrode. The preparation strategy demonstrates in this work can be useful for developing highly efficient electrocatalysts.     

Preparation and application of (Cu2O-Ag)@TA composite nanomaterials with enhanced stability and photocatalytic antibacterial activity

Food spoilage caused by bacterial growth is a serious threat to human health, so food preservation technology with long-acting antibacterial effect has been widely studied. In this work, (Cu₂O-Ag)@TA heterojunction composite antibacterial material with a core-shell structure was synthesized to improve the stability of Cu₂O. Morphological characterization shows that silver nanoparticles are uniformly distributed on the surface of Cu₂O microspheres, (Cu₂O-Ag)@TA has a core-shell structure, the particle size is about 300 nm, and the thickness of the tannic acid shell is about 6 nm. In addition, (Cu₂O-Ag)@TA exhibits excellent dispersibility and stability, it can stably release Cu²⁺ within 14 days and has enhanced reactive oxygen species release performance, thus achieving excellent antibacterial properties, with a minimum inhibitory concentrations of 96 μg ml⁻¹ against Escherichia coli and Staphylococcus aureus. In addition, adding (Cu₂O-Ag)@TA into the LbL-PVA/CS/FA composite film can improve the mechanical properties and antibacterial ability of the composite film, providing a feasible solution for new biodegradable antibacterial packaging materials.     

The role of ion-membrane interactions in fast and selective mono/multivalent ion separation with hierarchical nanochannels

Precise control over the nanofluid behavior of polyelectrolyte-based membranes is a primary step toward understanding the structure-morphology-property relationships to ultimately determine the mass transfer characteristics. In this study, a high-performance multistacked polyelectrolyte-based cation exchange membrane (CEM) with a heterogeneous structure and versatile surface chemistry was developed to achieve selective ion conductance. The self-assembled CEM can facilitate ion permeation with fluxes of 2.9 mol m⁻² h⁻¹ for K⁺ and 0.22 mol m⁻² h⁻¹ for Mg²⁺, reaching a mono/multivalent ionic selectivity of up to 13, outperforming mono/divalent fractionation when compared with state-of-the-art membranes. Molecular dynamic (MD) simulations illustrated the ionic transport trajectory in hierarchical channels with angstrom-scale cavities using multilayered CEMs. Both the experimental measurements and theoretical simulations indicated that ionic fractionation was associated with a large disparity in the energy barrier between mono/multivalent cations, which was the primary origin of the differences in the ion dehydration-rehydration processes in the angstrom-confinement membrane ion channels.     

Steering Electron Density of Zr Sites Using Ligand Effect in Bio-Beads for Efficient Defluoridation

Because of spontaneous agglomeration effect and undesirable electronic state of Zr sites on the surface, zirconium (hydro)oxides generally exhibit suboptimal defluoridation capacity. Herein, a template confinement-ligand anchoring strategy is developed by utilizing confined growth of zirconium hydroxide (ZH) inside chitosan hydrogel beads (CHB) and subsequent anchoring of fumaric acid (fm) on its surface Zr sites in a monodentate mononuclear coordination mode. This technique leads to uniform dispersion of ultrafine fmZH (≈3.4 nm) and tunable electron density at the Zr sites. Due to the electron-withdrawing ability of fm, electron-delocalized Zr sites increase the orbital energy level matching and vacate Zr 4d orbitals to promote hybridization with the F 2p orbitals. Ultimately, robust Zr F bond can be formed as a result of reduced the adsorption energy toward fluoride ions. The defluoridation capacity shows positive linear relationship with the electron extraction ability of ligands. The saturation adsorption capacity and dynamic treatment capacity of CHB@fmZH are 10.8 and 45.9 times higher than that of CHB@ZH, respectively, owing to high electron extraction (0.098 e⁻) of fm. This study offers a novel insight into the design and synthesis of high-efficiency metal oxide adsorbents by steering its surface metal sites’ electronic state through ligand effect.     

1996—2022年中国含益生菌保健食品调查分析

目的 系统调查中国含益生菌保健食品批准情况，分析菌种使用、功能声称、推荐摄入量和适宜人群分布情况，为益生菌类保健食品管理改革提供参考。方法 调查1996—2022年含益生菌保健食品的审批信息，对含益生菌种类、功能声称、推荐摄入量和适宜人群等信息进行统计分析。结果 1996—2022年中国共批准含益生菌保健食品168个，使用了乳杆菌属和双歧杆菌属的产品分别占82.14%和77.98%，61.31%的产品使用嗜酸乳杆菌，所有的产品均未明确到菌株水平；功能声称以“增强免疫力”“调节肠道菌群”和“通便”的产品居多；益生菌推荐摄入量为0.12~3.63×10¹¹ CFU/d；“免疫力低下者”“肠道菌群失调者”和“便秘者”是最常见的产品适宜食用人群，42.86%的产品未标注不适宜人群，标注不适宜人群的产品中69.79%为婴幼儿。结论 中国含益生菌保健食品目前审批的产品较少，产品标签标示均未明确到菌株水平，与益生菌的科学定义不符；现有产品功能单一，产品功能扩展要依赖高质量的人群试验研究结果；婴幼儿适用产品的审批应当科学谨慎。