Separation Efficiency Research Articles

Phase engineering of covalent triazine frameworks to enhance photocatalytic hydrogen evolution performance.

Photocatalytic water splitting for hydrogen production has been considered as an effective approach to address the current energy crisis and environmental challenges. Among all materials for such applications, covalent triazine frameworks (CTFs) are regarded as ideal candidates owing to their conjugated structures with rich aromatic nitrogen atoms, which can provide abundant active sites, suitable bandgaps, good structural tunability, and high chemical stability. Although current research studies have shown that the modification of functional groups in CTFs can adjust the band structure and carrier flow characteristics of photocatalysts, leading to improved performance, the impact of the intrinsic structural characteristics of CTFs (e.g., stacking modes, hydrogen bonding) on their photocatalytic performance remains unclear. In this paper, we demonstrate that the photocatalytic hydrogen evolution performance of CTFs can be enhanced through tuning their stacking arrangement, because the stacking modes affect the bandgaps of materials as well as their carrier separation and transfer efficiency. Under visible light conditions, CTF-AA (AA stacking) exhibited a hydrogen evolution rate of 4691.73 μmol g-1 h-1, which is 37.4% higher than that of CTF-AB (AB stacking, 3415.30 μmol g-1 h-1). Clearly, the stacking modes significantly influence the cycling stability of CTFs. After eight cycles (over 32 h), CTF-AA maintains its photocatalytic activity and initial performance with a slight decline, while CTF-AB only retains 56.8% of its initial hydrogen evolution rate. Theoretical calculations and physical characterization confirm that the transition of the stacking mode from AB to AA enhances interlayer overlapping, increases the energy level of the lowest unoccupied molecular orbital, and improves the separation and mobility of carriers. These combined factors significantly enhance the photocatalytic performance of CTF-AA. This work offers new insights into the relationship between the photocatalytic performance of CTFs and their stacking patterns, providing new guidelines for designing CTF catalysts with improved activity.

Simultaneous stereoisomeric preconcentration and determination of alkaloids and stereoisomers in Uncariae ramulus cum uncis using field enhanced sample injection and dynamic pH junction sweeping method by cyclodextrin electrokinetic chromatography.

A rapid and sensitive enrichment technique, field enhanced sample injection-dynamic pH junction-sweeping (FESI-DypH-sweeping) was successfully developed for the simultaneous separation and concentration of alkaloids and stereoisomers of Uncariae ramulus cum uncis (UR) by cyclodextrin electrokinetic chromatography (CDEKC) with diode array detection system. The sample was prepared in a low-conductivity (FESI), low-pH (DypH) sample matrix (4 mM phosphate buffer, 3% methanol, pH=3), and the background electrolyte (BGE) consisted of a high-conductivity, high-pH buffer (40 mM phosphate buffer, pH 7.0, 8 mg/mL carboxymethyl-β-cyclodextrin, and 30% methanol). The crucial parameters influencing separation and enrichment efficiency were systematically optimized using single variable method. Under the optimum conditions, the method provided satisfactory resolution for seven alkaloids within 18 minutes, achieving enrichment factors ranging from 25 to 78 folds. The limits of detections (LODs) ranged from 0.04 to 0.12 μg/mL and limits of quantifications (LOQs) ranged from 0.10 and 0.40 μg/mL respectively. Intra-day and inter-day precision, expressed as relative standard deviations, were all below 3.5%.

Improving the Photocatalytic Performance of TiO2 Coating via the Dual Incorporation of MoO2 and V2O5 by Plasma Electrolytic Oxidation

In this study, the photocatalytic activity of TiO₂ coatings on pure titanium was significantly enhanced through the dual incorporation of MoO₂ and V₂O₅ particles. This enhancement was achieved by performing a series of plasma electrolytic oxidation (PEO) treatments in an alkaline-phosphate electrolyte, where Na₂MoO₄ and V₂O₅ nanoparticles were added either individually or in combination. The PEO process was carried out at a current density of 100 mA/cm² for 5 minutes. The results revealed notable changes in the surface morphology of the TiO₂ coatings, with increased porosity and pore size observed upon the addition of MoO₄ ions, while the incorporation of V₂O₅ nanoparticles led to a slight reduction in pore size. Interestingly, the simultaneous addition of both MoO₂ and V₂O₅ resulted in a porous structure with medium pore size and porosity, which proved optimal for photocatalytic applications. The compositional analysis confirmed the successful incorporation of MoO₂ and V₂O₅ into the TiO₂ matrix via electrochemical decomposition and electrophoresis mechanisms. Photocatalytic performance was evaluated through the degradation of methylene blue (MB) under visible light. The results demonstrated that the combined incorporation of MoO₂ and V₂O₅ significantly improved the degradation efficiency compared to TiO₂ coatings prepared without these additives. Notably, the TiO₂ coating with both additives achieved 99.9 % degradation of MB within 80 minutes, indicating enhanced charge separation and photocatalytic efficiency. This study highlights the potential of dual additive incorporation to improve the functional properties of TiO₂ coatings, making them suitable for advanced environmental and industrial applications.

Prolonged stirring pelleting coagulation for the enhanced treatment of fresh leachate: Removal performance and floc characteristics

Conventional coagulation (CC) is a widely adopted method for the pre-treatment of fresh leachate for enhancing subsequent advanced treatment processes. However, the formation of fluffy flocs in the CC process often results in limited separation and removal efficiency. In this study, a continuous alkali dosing prolonged stirring pelleting coagulation (C-PPC) process was proposed for the pre-treatment of fresh leachate. The C-PPC process consisted of three stages: prolonged stirring, reaction, and pelleting, achieving higher suspended solid (SS), turbidity, and organic removal efficiency compared with both CC and PPC processes. At a prolonged stirring intensity of 1500 r/min (G = 4241 s−1) and a final pH of 12, with polyaluminum chloride (PAC) and polyacrylamide (PAM) dosages of 2000 mg/L and 25 mg/L, impressive removal efficiency of 93.7 % SS, 99.7 % turbidity, and 35.7 % organic were obtained. In the prolonged stirring stage, the primary particle size decreased from 16.848 μm to 6.755 μm due to intensive stirring for 30 min, facilitating the compact floc formation. In the subsequent reaction stage, PAC was dosed once while NaOH was continuously dosed to achieve a final pH of 12 within 10 min. The floc size initially decreased due to fragmentation and small metal crystal generation. Subsequently, the generated small metal crystals served as the nuclei for organic matter adsorption and were entrapped by generated flocs, resulting in a significant increase in floc size with higher sphericity. Furthermore, compact pellets were formed during the pelleting stage after the addition of PAM. Floc restructuring also occurred during the pelleting stage, leading to a decreased pore volume of mesopores, achieving final floc densification and superior separation performance.

Construction of defect-free MMMs with ultrahigh MOFs loading by a novel “bottom-up” strategy for efficient H2 separation

Construction of defect-free MMMs with ultrahigh MOFs loading by a novel “bottom-up” strategy for efficient H2 separation

Highly efficient charge carrier separation in ZnO-NiFe2O4@biochar Z-scheme heterojunction mediated by persistent free radicals for metronidazole degradation

Highly efficient charge carrier separation in ZnO-NiFe2O4@biochar Z-scheme heterojunction mediated by persistent free radicals for metronidazole degradation

Efficient flotation separation mechanism of scheelite from calcite and fluorite using carboxymethyl sulfonated lignin as environmentally friendly depressant

Efficient flotation separation mechanism of scheelite from calcite and fluorite using carboxymethyl sulfonated lignin as environmentally friendly depressant

A robust, efficient ion transport polytetrafluoroethylene fibrous membrane-based separator with superior stability for ultralong-life zinc ion hybrid supercapacitors

A robust and efficient ion transport PTFE-based separator with superior stability was fabricated for zinc ion hybrid supercapacitors, demonstrating excellent electrochemical performance.

Breaking the Symmetry of Interfacial Molecules with Push-Pull Substituents Enables 19.67% Efficiency Organic Solar Cells Featuring Enhanced Charge Extraction

The symmetry of a molecule governs its electronic structure, dipole moment, electrostatic potential, and molecular interactions. Symmetry breaking is frequently adopted in donor and acceptor materials for efficient charge separation...

Enhanced capacity in cellulose aerogel for carbon dioxide capture through modified by metal-organic framework.

Microporous metal-organic frameworks (MOF) exhibit excellent carbon dioxide (CO2) adsorption performance and selectivity for CO2/N2 separation. However, the challenges associate with the recycling and reuse of MOF powders hinder their practical applications. To address these limitations, a flexible and stable MOF-based composite material was designed by immobilizing UiO-66(Zr)-(OH)2 onto cellulose nanofibers (CNFs) aerogels (MOF-CNFs), which featured high porosity. Experimental results showed that MOF-CNFs exhibited sensitivity to CO2 adsorption at low pressure and achieved a CO2 adsorption capacity of 1.8 mmol/g at 0.15 bar under the 298 K. This represented an 8.8 % improvement compared to the MOF. Ideal adsorbed solution theory (IAST) calculations indicated selectivity for CO2/N2 mixtures (molar ratio 15:85) as high as 66. After eight adsorption-desorption cycles, the CO2 adsorption capacity retained 97 % of its initial value. These results highlighted the significant potential of MOF-CNFs as reusable and highly efficient CO2 separation adsorbents for practical applications, such as flue gas capture.

A new mesoporous Ce-Mn-LDH-based Co-MOF nano-composite for the green synthesis of tetrazoloquinazolines.

Tannic acid (TA), as a plant polyphenol, has many active sites for chelation with metals, so TA-oligomers (TA-Olig) were used for the first time as ligands on the surface of Ce-Mn-LDH to prepare the layered double hydroxide-based metal-organic framework (Ce-Mn-LDH@CPTMS@TA-Olig@Co-MOF = E) nanocomposite. In this regard, a homogeneous water/ethanol solution was prepared by sol-gel method using polyethylene glycol and ammonia solution, and then TA was converted into a set of oligomers in the presence of formaldehyde. In the next step, Ce-Mn-LDH was prepared in a ratio of 1 : 4 of Ce to Mn, modified with 3-chloropropylmethoxysilane, functionalized by TA-Olig, and then cobalt salt was used to prepare E. Finally, the structure of E was determined by FT-IR, ICP, XRD, BET, EDX, SEM, SEM-mapping, TEM, and TGA-DTA techniques and used as a new and potent nanocatalyst for the synthesis of tetrazoloquinazolines a(1-12). One of the advantages of this nanocatalyst is the active surface to form products in a limited time in mild conditions with high efficiency and easy separation. Also, the catalytic activity is maintained even after four consecutive runs.

Three-dimensional multiscale superhydrophobic thermoplastic polyurethane/SiO2 nanowire composite sponges for durable and efficient oil-water separation

Three-dimensional multiscale superhydrophobic thermoplastic polyurethane/SiO2 nanowire composite sponges for durable and efficient oil-water separation

Linear PDI-based conjugated polymers with directional charge transport driving photocatalytic water oxidation

A linear conjugated organic polymer based on PDI was designed for directional charge transfer, it exhibits efficient charge separation that move along the chain direction. The above properties enable water oxidation for O2 production by PT-CB.

Ratiometric fluorescent aptasensor based on DNA-gated Fe3O4@Uio-66-NH2 and Exo I-assisted signal amplification.

Ochratoxin A (OTA) is toxic secondary metabolites produced by fungi and can pose a serious threat to food safety and human health. Due to the high stability and toxicity, OTA contamination in agricultural products is of great concern. Therefore, the development of a highly sensitive and reliable OTA detection method is crucial to ensure food safety. Although fluorescent sensors have been widely used for OTA detection, they still face challenges such as false positives and insufficient sensitivity, thus further improvement of the detection performance is necessary. Herein, a ratiometric biosensor based on DNA-gated Fe₃O₄@Uio-66-NH₂ nanocomposites and Nucleic Acid Exonuclease I (Exo I)-assisted signal amplification was constructed for the sensitive detection of OTA. This functional nanocomposite combines magnetic, porous and fluorescent properties. Fe₃O₄ of the core enables efficient magnetic separation, while the porous structure of Uio-66-NH₂ encapsulates the fluorescent dye rhodamine 6G (Rho 6G). In addition, a label-free DNA gating strategy was introduced to control the release of Rho 6G. The sensor performs OTA detection by the fluorescence signal ratio of Fe3O4@Uio-66-NH2 and Rho 6G, which effectively avoids false positives of the sensor. Accelerated release of Rho 6G using Exo I greatly improves the sensitivity of the sensor. The sensor has a low LOD (0.308ngmL-1) and the recoveries for OTA detection in real samples were 92.4%-116.0%. The development of this ratiometric fluorescent aptasensor highlights its potential for highly sensitive OTA detection, offering significant advantages in selectivity and accuracy due to its unique DNA-gated mechanism and the dual fluorescence signal ratio strategy. Additionally, the use of Fe₃O₄@Uio-66-NH₂ enables effective magnetic separation, while the Exo I-assisted signal amplification enhances sensitivity, making this sensor a powerful tool for detecting OTA in complex sample matrices with high reliability.

Fabrication of vertical structure type bimetallic MOF@ biomass aerogels for efficient CO2 capture and separation

Fabrication of vertical structure type bimetallic MOF@ biomass aerogels for efficient CO2 capture and separation

Green and sustainable aerogel from chitosan and Caragana biochar for efficient, continuous and large-scale separation of complex emulsion

Green and sustainable aerogel from chitosan and Caragana biochar for efficient, continuous and large-scale separation of complex emulsion

A novel sulfuric acid pretreatment process for the efficient flotation separation of copper and lead: the key role of atmosphere and pressure

A novel sulfuric acid pretreatment process for the efficient flotation separation of copper and lead: the key role of atmosphere and pressure

A biomimetic 3D DNA nanoplatform for enhanced capture and high-purity isolation of stem cell exosomes.

Exosomes are uniformly sized vesicle-like bodies that cells secrete. Researchers now believe that exosomes can mediate various health and pathological processes. However, because the biophysical properties of exosomes are similar to those of other cell secretion products and biological fluids are rich and diverse, their separation and purification have always been challenging. Inspired by the adhesive domains in the tentacles of marine organisms that effectively capture and release mobile food particles, we have built a biomimetic 3D DNA nanoplatform. This platform not only captures exosomes efficiently but also allows for light-controlled exosome release. The surface of the 3D DNA nanoplatform can grow multivalent aptamers via rolling circle amplification. Aptamers fold into specific secondary structures that bind to CD63, a protein expressed on the surface of exosomes, enabling efficient exosome capture. As a photothermal reagent, the temperature of the DNA nanoplatform increases under near-infrared light irradiation, destroying the secondary structure of the CD63 aptamer and releasing the exosomes. Additionally, we have demonstrated that a 3D DNA nanoplatform with multivalent CD63 aptamer structures achieves more efficient and convenient stem cell exosome separation compared to ultracentrifugation. This strategy provides an efficient and high-purity way to capture and reversibly separate exosomes, and the separated ultrapure exosomes are used for enhancing wound healing by modulating migration and angiogenesis.

Surfactants govern the fabrication of sulfur-enriched heterojunction catalysts for highly selective photocatalytic conversion of toluene

Photocatalytic selective oxidation of toluene represents a milder and more environmentally friendly strategy for the synthesis of benzaldehyde. In order to enhance catalytic performance, efficient carrier separation and transport are crucial in the photocatalytic process. This study focused on the preparation of ZnS@ZnIn2S4 with sulfur vacancies and heterostructures, combining the advantages properties of ZnS and ZnIn2S4 in photocatalysis. The effects of ZnS and surfactants on the catalytic properties of the composites were studied in depth. Characterization tests revealed that surfactant-modified ZnS@ZnIn2S4 exhibited a higher concentration of sulfur defects, which facilitated electron trapping and promoted photogenerated carrier separation and utilization. Additionally, the present study also demonstrated that the incorporation of ZnS and surfactants could reduce the crystal size of ZnIn2S4, thereby facilitating the exposure of additional active sites. The synergistic effect of the aforementioned advantages enabled toluene to undergo oxidation at a conversion rate of 39% in the presence of oxygen, resulting in the production of benzaldehyde with an exceptional selectivity of 92%. This finding offers valuable insights for future endeavors in designing photocatalytic C-H bond oxidation catalysts.

Bimetallic PdPt nanoparticle-incorporated PEDOT:PSS/guar gum-blended membranes for enhanced CO2 separation.

To address the escalating demand for efficient CO2 separation technologies, we introduce novel membranes utilizing natural polymer guar gum (GG), conjugate polymer (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) PEDOT:PSS, and bimetallic PdPt nanoparticles. Bimetallic PdPt nanoparticles were synthesized using the wet chemical method and characterized using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) techniques. The morphologies, chemical bonds, functional groups, and mechanical properties of the fabricated membranes were characterized using various techniques. Through meticulous fabrication and characterization, the binary blended membranes demonstrated enhanced homogeneity and smoothness in their structure, attributed to the interaction between the polymers, and superior CO2 permeability due to the amphiphilic nature of the PEDOT:PSS polymer. Gas separation experiments performed using H2, N2, and CO2 gases confirmed that the 20% PEDOT:PSS/GG blended membranes showed the best performance with sufficient mechanical properties. Moreover, the results demonstrated an increase of 172% in CO2 permeability and 138% in CO2/H2 selectivity, respectively. Furthermore, integrating bimetallic PdPt nanoparticles provided an additional 197% increase in CO2/H2 selectivity, owing to the unique catalytic activities of noble metal nanoparticles. The study not only underscores the transformative potential of polymer blending and noble metal engineering, but also highlights the significance of using natural polymers for sustainable environmental solutions.