Supported membranes and mixed matrix membranes have a limitation of harming the mass transfer due to the incompatibility between the support layer or the matrix and the active components of the membrane. Self-standing membranes, which could structurally abandon the support layer, altogether avoid the adverse effect, thus greatly facilitating the transmembrane mass transfer process. However, the abandonment of the support layer also reduces the membrane\'s mechanical properties and formability. In this review, our emphasis will be on self-standing membranes within the realm of materials and separation engineering. We will explore the materials employed in the fabrication of self-standing membranes, highlighting their ability to simultaneously enhance membrane performance and promote self-standing characteristics. Additionally, we will delve into the diverse techniques utilized for crafting self-standing membranes, encompassing interfacial polymerization, filtration, solvent casting, Langmuir-Blodgett & layer-by-layer assembly, electrospinning, compression, etc. Throughout the discussion, the merits and drawbacks associated with each of these preparation methods were elucidated. We also provide a brief overview of the applications of self-standing membranes, including water purification, gas separation, organic solvent nanofiltration, electrochemistry, and membrane reactor, as well as a brief description of the general strategies for performance enhancement of self-standing membranes. Finally, the current status of self-standing membranes and the challenges they may encounter were discussed.

Mesoporous silica SBA-15 has emerged as a promising adsorbent and separation material due to its unique structural and physicochemical properties. To further enhance its performance, various surface modification strategies, including metal oxide and noble metal incorporation for improved catalytic activity and stability, organic functionalization with amino and thiol groups for enhanced adsorption capacity and selectivity, and inorganic-organic composite modification for synergistic effects, have been extensively explored. This review provides a comprehensive overview of the recent advances in the surface modification of SBA-15 for adsorption and separation applications. The synthesis methods, structural properties, and advantages of SBA-15 are discussed, followed by a detailed analysis of the different modification strategies and their structure-performance relationships. The adsorption and separation performance of functionalized SBA-15 materials in the removal of organic pollutants, heavy metal ions, gases, and biomolecules, as well as in chromatographic and solid-liquid separation, is critically evaluated. Despite the significant progress, challenges and opportunities for future research are identified, including the development of low-cost and sustainable synthesis routes, rational design of SBA-15-based materials with tailored properties, and integration into practical applications. This review aims to guide future research efforts in developing advanced SBA-15-based materials for sustainable environmental and industrial applications, with an emphasis on green and scalable modification strategies.

In this study, high-performance liquid chromatography was used to determine four components of Shaoyao Gancao Decoction (SGD), and the effect of purification was evaluated using fingerprints, similarity analysis and cell experiments. An effective method for isolation and purification of SGD was established. The adsorption/desorption properties of SGD were evaluated using resin screening, isothermal analysis, adsorption kinetics, and dynamic adsorption-desorption experiments. It was shown that the Langmuir equation fitted the isotherm data well and that a pseudo-second-order model accurately described kinetic adsorption on AB-8 resin. Analysis of thermodynamic parameters showed that the adsorption process was exothermic. Under the optimal process conditions, the concentrations of albiflorin, paeoniflorin, liquiritin and ammonium glycyrrhizinate in the product were 73.05, 134.04, 45.04 and 75.00 mg/g, respectively. The yields of the four components were 71.89 %-86.19 %. Cell experiments showed that the purified SGD retained anti-inflammatory activity. This research lays the foundation for the separation and purification of SGD and subsequent preparation research.

Rare earth elements with unique magnetic properties and optical properties, known as the \'industrial vitamin\', has a very high commercial value. As a secondary resource of rare earth elements, low-concentration solution includes mixed rare earth ions, which need to realize efficient separation and recovery urgently. High speed countercurrent chromatography is suitable for the separation and purification of rare earth element ions due to its advantages of large loading, good tolerance to samples, and simple pretreatment. In this study, a carbon dots assisted high speed countercurrent chromatography method was designed and established, the carbon dots were applied to the mobile phase of high speed countercurrent chromatography for the first time. The low concentration of REEs solution was enriched, and the effective separation of La (III), Ce (III), Gd (III) and Er (III) was successfully achieved. The complete separation of La (III), Ce (III), Gd (III) and Er (III) was achieved with a solvent system of 0.05 mol L-1 P507 (PE), 0.05 mol L-1 HNO3, and 0.1 mol L-1 CDs2 carbon dots (1:1:0.01, v/v/v), the upper phase as stationary phase, the lower phase as mobile phase. Density functional theory result showed that the binding energy of REEs (III)-CDs2 was larger than that of REEs (III)-P507, so the affinity of CDs2 to REEs (III) was stronger than that of P507. Therefore, with the addition of CDs2, the ability of mobile phase to elute REEs from the stationary phase was enhanced, and the separation effect was improved.

BACKGROUND: Peanut peptides can chelate iron but their chelation mechanism remains unclear. The purpose of this study is to separate peanut ferrous-chelating peptides and explore the chelation mechanism of peanut peptides with iron.
RESULTS: Peanut peptide component F-122, which had a higher chelation rate, was separated using ultrafiltration, gel filtration chromatography, and ion exchange chromatography, achieving a ferrous chelation rate of 90.7%. Six peptide segments were screened and their amino acid sequences were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Spectral analysis confirmed that the chelation between peanut peptides and ferrous ions occurred and a new substance was formed. Molecular docking simulation indicated that the amino acids in peanut peptides involved in the chelating reaction were glutamic acid, arginine, glycine, threonine, phenylalanine, and lysine. The binding sites included the main chain oxygen atom, side chain oxygen atom, and carboxyl oxygen atom of amino acid.
CONCLUSIONS: The isolated peanut peptide had a higher ferrous-chelation rate. The chelating mechanism of peanut peptide with ferrous ion was elucidated. This study provides a theoretical basis for the development of new peptide-ferrous preparations. © 2024 Society of Chemical Industry.

The accumulation of excess Low-density lipoprotein (LDL) is strongly associated with the occurrence of heart failure, coronary artery disease and hypercholesterolaemia, and is a major factor in cardiovascular and cerebrovascular disease. Concerns about the ways to decrease LDL level have continuously arisen. In this study, an ionic stimulation-responsive composite (i.e., GO@Apt@SA) is prepared with modification of graphene oxide (GO) utilising LDL-aptamer (Apt) and sodium alginate (SA). The ion-responsive behaviour of GO@Apt@SA synergistically interacts with the specific recognition property of the aptamer, enabling adsorption of LDL with higher capacity and specificity. Under the optimal experimental conditions, the maximum adsorption capacity of GO@Apt@SA for LDL is 730.6 μg mg-1. Interestingly, the aptamer complementary chain could trigger the release of LDL with favourable elution efficiency, which competitively binds with LDL-specific aptamer to trigger LDL release. More importantly, GO@Apt@SA exhibits satisfactory adsorption performances for LDL in goat serum, meaning that the composite material and technology are available for the extraction of LDL from complex sample matrices.

Landfilled metallurgical residues are valuable raw materials for the recovery of strategic vanadium resources. However, efficient separation of vanadium from these residues is challenging due to its strong oxidation resistance and coating within silicate inclusions. To address this issue, this study proposes an enhanced leaching process utilizing the synergistic effect of O3-catalyzed ultrasonic field in a low concentration sulfuric acid system. Results show that following a 10-minute O3 and ultrasonic treatment, the direct leaching rate of vanadium experienced a remarkable 46.7 % increase. Quenching experiments revealed a hierarchical order of active species within the reaction process:⋅OH >⋅O2-> H+, with⋅OH oxidation exhibiting the most pronounced capacity for disrupting the inclusion structure. Electron Paramagnetic Resonance analysis indicated that the highest⋅OH yield arose from the combined application of ultrasound and ozone. Kinetic investigations demonstrated that the vanadium leaching process is governed by interfacial chemical reactions. The activation energy of vanadium oxidation leaching under ultrasonic-O3 conditions was determined to be 40.41 kJ/mol, representing a 20.19 % reduction compared to ultrasonic conditions alone. Through the integration of analysis, characterization, and comparative evaluations, it was discerned that the synergistic impact of ultrasonic and ozone treatments significantly enhances the breakdown of silicate inclusions by low-concentration HF, particularly in the conversion of SiOSi bonds into SiOH bonds and SiF bonds. In summary, the refined leaching methodology incorporating ozone catalysis in conjunction with ultrasonic treatment provides a new idea for the separation and extraction of refractory residual vanadium.

Tubers of Gymnadenia conopsea (L.) R. Br. (Orchidaceae), a traditional medicine and food homologous plant, has a broad application and development prospect in the food and drug industries. Benzylester glucosides, the main effective active components in this plant, are difficult to separate due to their similar structures and high polarity. In this study, linear gradient counter-current chromatography was used to separate benzylester glucosides and derivatives, combined with elution-extrusion mode. The main separation parameters were optimized, including the ratio of mobile phase and sample loading. Finally, seven compounds were successfully separated, including 4-hydroxybenzyl alcohol (1), 4-hydroxybenzaldehyde (2), dactylorhin B (3), loroglossin (4), dactylorhin A (5), 4-(ethoxymethyl) phenol (6), and militarine (7). The structures were analyzed by mass spectrometry and nuclear magnetic resonance spectrometry. According to our findings, the established method was an efficient approach to separate benzylester glucosides and derivatives from tubers of G. conopsea. The established strategy could be applied to purify other similar high-polarity compounds from complex natural products.

Membrane separation stands as an environmentally friendly, high permeance and selectivity, low energy demand process that deserves scientific investigation and industrialization. To address intensive demand, seeking appropriate membrane materials to surpass trade-off between permeability and selectivity and improve stability is on the schedule. 2D materials offer transformational opportunities and a revolutionary platform for researching membrane separation process. Especially, the atomically thin graphene with controllable porosity and structure, as well as unique properties, is widely considered as a candidate for membrane materials aiming to provide extreme stability, exponentially large selectivity combined with high permeability. Currently, it has shown promising opportunities to develop separation membranes to tackle bottlenecks of traditional membranes, and it has been of great interest for tremendously versatile applications such as separation, energy harvesting, and sensing. In this review, starting from transport mechanisms of separation, the material selection bank is narrowed down to nanoporous graphene. The study presents an enlightening overview of very recent developments in the preparation of atomically thin nanoporous graphene and correlates surface properties of such 2D nanoporous materials to their performance in critical separation applications. Finally, challenges related to modulation and manufacturing as well as potential avenues for performance improvements are also pointed out.

Acteoside (ACT) was the main bioactive components in phenylethanoid glycosides of Cistanche tubulosa. Currently, the development of an efficient method for selectively separating ACT was crucial. Consequently, yolk-shell magnetic mesoporous carbon (YSMMC) was synthesized as a nanofiller to prepare molecularly imprinted membranes (ACT-MIMs) with instant noodles-like structure for selectively separating ACT. The numerous YSMMC were moved to the upper surface of ACT-MIMs by magnetic guidance and constructed the instant noodles-like structure in ACT-MIMs. The instant noodle-like structure increased the surface roughness of ACT-MIMs, which was conducive to improving the effective imprinted interface, increasing the selectivity of ACT-MIMs. In addition, the instant noodle-like structure had dendritic interleaved pathways in ACT-MIMs. The dendritic interleaved pathways can intercept ACT through ACT-MIMs, enhancing the permselectivity of ACT-MIMs. The prepared YSMMC possessed the dendritic shell and interlayer cavity structure can provide a great accommodation space, improving the rebinding capacities of ACT-MIMs. The high permselectivity (14.49), remarkable selectivity (7.52), and excellent rebinding capacity (120.48 mg/g) were achieved for the prepared ACT-MIMs. Thus, the design of ACT-MIMs with the instant noodles-like structure were valuable for selectively separating of bioactive components.