Hydroxyl Research Articles

Constructing potassium and hydroxyl co-doped dual-dipole structures on highly active 3D g-C3N4 surfaces for highly boosting photocatalytic hydrogen peroxide production efficiency in pure water

Producing hydrogen peroxide (H2O2) through visible-light-driven photocatalytic oxygen reduction in pure water is crucial for sustainable ecological applications but poses significant challenges. These include the rapid recombination of electron-hole pairs and a scarcity of effective catalytic sites, which traditionally limit the process efficiency. To address these issues, we have developed a novel catalyst, designated as KCNOH, which consists of a three-dimensional (3D) porous g-C3N4 framework doped with potassium (K+) and modified with surface hydroxyl groups (-OH). This design significantly enhances H2O2 yield, achieving 91.36 μmol g-1 h-1 (cut 420 nm)—a yield approximately 36 times higher than conventional bulk g-C3N4 (2.57 μmol g-1 h-1). The introduction of a 3D porous structure provides an abundance of active-sites. The dual-dipole mechanism, facilitated by K+ ions and hydroxyl groups, plays a pivotal role by efficiently transporting photogenerated electrons and consuming holes, respectively. Through density functional theory (DFT) calculations, the changes in the band structure of the catalyst caused by the doping of potassium and the grafting of hydroxyl groups were elucidated. In addition, the transition state affinity of oxygen induced by the -OH group was also studied to reveal the synergistic catalytic mechanism. This mechanism markedly reduces carrier recombination and accelerates charge migration, underscoring its importance in catalyst design. Our findings not only improve the understanding of charge dynamics but also open novel perspectives for the design of highly-efficient composite materials, crucial for energy and environmental applications.

Microscopic removal mechanism of 4 H-SiC during abrasive scratching in aqueous H2O2 and H2O: Insights from ReaxFF molecular dynamics

Single-crystal silicon carbide (SiC) substrates with ultra-smooth and low-damage characteristics are at the core of high-power chip manufacturing. However, their high hardness and brittleness pose significant challenges to the polishing process. Although current polishing methods based on chemical reactions and mechanical induction removal improve polishing efficiency, the microscopic removal mechanism remains unclear. In this study, the single-diamond abrasive scratching process of 4 H-SiC was investigated in aqueous H2O2 and pure H2O using ReaxFF molecular dynamics. The simulation results showed that the three reactants of Si-OH, Si-O, and Si-H appeared on the silicon surface, and the hidden C atoms were exposed under scratching by the abrasive and oxidised C-O functional groups. The Si and C atoms in SiC were removed in the mechanical, adhesive, and oxidative forms owing to the continuous extrusion and shearing of the abrasive. In addition, the difference between 4 H-SiC in aqueous H2O2 and pure H2O environments is mainly reflected in the number of hydroxyl (-OH) groups produced. Aqueous H2O2 can decompose and promote H2O molecules to produce more -OH groups, resulting in more atoms being oxidised and removed. These results have guiding significance in revealing the polishing removal mechanism of the 4 H-SiC substrate.

Unravelling the nature differences of halide anions affecting the sorption of U(VI) by hydrous titanium dioxide supported waste polyacrylonitrile fibers in the presence of carbonates

The co-occurrence of halides and carbonates with uranium in the natural water poses a challenge to the uranium recovery for nuclear power due to the potential complexation. Hydrated titanium dioxide (HTD) contains a lot of surface hydroxyl (–OH) groups and waste polyacrylonitrile fiber (WPANF) has the advantages of both weather and chemical resistances. Herein, the nature differences of halide anions affecting the sorption of U(VI) by WPANF/HTD was investigated in the presence of carbonates. The sorption capacity (qe) decreased with the increases of initial pH, total carbonates, and halides but increased at high temperature and initial U(VI) concentration. The U(VI) sorption was a spontaneous chemisorption, which mainly involved surface sorption rather than intra-particle diffusion. The order of inhibitory ability on U(VI) sorption for the four halides was F > I ~ Br > Cl. The aqueous F− was shown to be the most strongly inhibited with the lowest qe value of 17.2 mg·g−1, due to the formation of U(VI)–F complex anions. The characteristic peaks with weakened relative intensity after U(VI) sorption for the surface –OH groups on HTD (HTD–OH), together with the results from DFT calculations, demonstrated a key role of HTD–OH in U(VI) sorption by WPANF/HTD via the coordination with U(VI) complex anions. This work unravels the nature differences of halide anions affecting U(VI) sorption in the presence of carbonates and provides a valuable reference for the U(VI) extraction toward halogen-rich natural uranium-containing water.

P(MMA-co-MAA)/cellulose nanofibers composites: Effect of hydrogen bonds on molecular mobility

Cellulose nanofibers (CNFs) nanocomposites were prepared using poly(methylmethacrylate-co-methacrylic acid) (PMMA-co-MAA) to investigate the macromolecular mobility within the composite, with particular focus on the effect of H-bonding. Dynamic mechanical analysis (DMA) and broadband dielectric spectroscopy (BDS) were used to fully characterize the molecular mobility for which the effect of the introduction of H-bond forming moieties and the addition of CNFs (5 and 15 wt%) were assessed. Despite similar Tg values (determined by Differential Scanning Calorimetry), a deeper analysis of the relaxation times associated with the α-relaxation evidenced a significant effect induced by CNFs, which is in fact slowing down the macromolecular relaxation processes. The activation energy of the β-relaxation remained unchanged despite the introduction of MAA units in the main chain and the successive addition of CNFs. However, the latter led to the appearance at low frequencies of a new β’-relaxation correlated with the interactions between the CNF surface -OH groups and the -COOH groups of the matrix. The γ-relaxation showed a 45 % increase in activation energy from PMMA to PMMA-co-MAA + CNF nanocomposites regardless of the CNF content, due to the possibility of CNFs to interact and hinder the motion of the main chain methyl groups in α position.

Influence of hydroxyl group density in propane alcohols-based deep eutectic solvents: Physicochemical properties and potential application as an extraction medium for bioactive compounds

Deep eutectic solvents (DES) composed of citric acid monohydrate (CAM) as hydrogen bond acceptor (HBA) and alcohol as hydrogen bond donor (HBD) were used for separating bioactive compounds from star anise. This study prepared three propane alcohols-based DES with different hydroxyl (OH) group densities in HBD. FTIR analysis verified the presence of hydrogen bond interactions between HBA and HBD, which strengthened with increasing the OH group densities. Increasing the OH group density in DES exhibited lower water content, but higher thermal stability, higher density, higher viscosity as well as enhanced the water absorption rate. All of the propane alcohols-based DES were miscible in high and semi-polar solvents as well as it also displayed frequency independence characteristics. Moreover, propane alcohols-based DES efficiently extracted bioactive compounds from star anise with high total phenolic and flavonoid contents more than traditional solvents. High bioactive phenolic and flavonoid contents in star anise extracts were the major contributors to potent antioxidant activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH, 84.50 %), azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS, 85.73 %), and ferric ion reducing antioxidant power (FRAP, 3.74 mM FeSO4). Therefore, DES was suggested to be a promising extraction medium for valuable bioactive compounds from natural sources that could be utilized as therapeutic agent for oxidative stress.

Effect of surface hydroxyl group density of support membrane on water permeance of polyamide thin-film composite membrane

Polyamide-based thin-film composite (TFC) membranes are widely used in water treatment processes. Recently, the influence of support membranes on the performance of polyamide layers has garnered considerable attention. Regarding the chemical properties of the support membranes, the surface wettability and the interaction between the amine monomer used for interfacial polymerization and the membrane surface are considered to play crucial roles. In this study, we investigated the effect of the wettability of the support membrane surface and its interaction with the amine monomer on the water permeance of TFC membranes. We prepared TFC membranes on polyketone support membranes with varying surface hydroxyl group densities and aqueous solution wettabilities. While no clear correlation was observed between the support membrane's wettability and the water permeance of the TFC membrane, an increase in hydroxyl group density did result in higher water permeance. The hydroxyl groups interact with PIP, inhibiting PIP diffusion and potentially leading to the formation of a thinner polyamide layer, which enhances water permeance. Therefore, the interaction between the amine monomer and support membrane surface strongly affects the formation of the polyamide layer.

Molecular dynamic simulation on comprehensive performance of ferrocene-based burning rate catalysts in a solid propellent

To determine the compatibility and interaction between ferrocene (Fc) and other components in AP/HTPB/Fc-based BRCs propellant, molecular dynamics simulation (MD simulation) method was used to study the binding energy, cohesive energy density (CED), mean square displacement (MSD) and mechanical properties of mononuclear ferrocene (ethyl ferrocene, butyl ferrocene and octyl ferrocene), binuclear ferrocene (2,2-(ethyl ferrocene) propane, 2,2, -bis-(butylferrocene) propane and hydroxymethyl bis-ferrocenyl propane), ionic ferrocene (three ionic ferrocenes with ferrocene methyl dimethyl ammonium as cation, perchlorate, nitrate and picrate as anions respectively) and cyclic ferrocene (1- ferrocenyl methyl -2- ferrocenyl -3- methylbenzimidazolium, binuclear ferrocene bridged by bridged biphenylferrocene and dihydropyrazole).The binding energy results show that alkyl groups, polar groups (such as hydroxyl groups) and cyclic substituents can improve the interaction between Fc and AP/HTPB. Moreover, the electrostatic interaction between ionic ferrocene and AP is strong, but the van der Waals interaction between ionic ferrocene and HTPB is weak. The CED data show that the mixed models based on alkyl mononuclear ferrocene, catocene, cyclic ferrocene and ionic ferrocene all have high cohesive energy with good safety performance. The MSD results show that the order of anti-migration ability is cyclic ferrocene > binuclear alkyl ferrocene > mononuclear alkyl ferrocene > binuclear hydroxyl ferrocene > ionic ferrocene. Regarding to the value of mechanical parameters (K, G, E and K/G), the mixed model of AP/HTPB/ dihydropyrazole bridged binuclear ferrocene possess the best mechanical properties among the 12 models. Based on the comprehensive data, we conclude that dihydropyrazole bridged binuclear ferrocene is the most ideal ferrocene-based burning rate catalyst among 12 ferrocenes.

A highly photostable UVA filter derived from avobenzone

Avobenzone was derivatized to avo-glycerol by replacing the p-methoxy group with glycerol at the ortho position. Avo-glycerol exhibited absorption in the UVA range (315–400 nm), similar to avobenzone, indicating good UVA coverage. Unlike avobenzone, a solution of avo-glycerol in an aprotic solvent demonstrates remarkable photostability, with no significant decrease in absorbance at the UVA range after 6 h irradiation. This suggests that the hydroxyl group in avo-glycerol functions as an efficient acid-base catalyst in enolization. Consequently, the rapid enolization of the photochemically generated keto form prevents its accumulation. This inherent photostability of avo-glycerol eliminates the need for photo stabilizers in sunscreen formulations and provides greater flexibility in selecting other sunscreen components.

Cross-linking impacts the physical properties of mycelium leather alternatives by targeting hydroxyl groups of polysaccharides and amino groups of proteins

Cross-linking, also called tanning, improves mechanical properties of leather and also increases its enzymatic and thermal stability. As a final product, leather has an ultimate tensile strength (σ) of 8–25 MPa and an elongation at break (ε) of >30 %. Mycelium-based materials are a sustainable alternative to leather. Here, the effect of cross-linkers was assessed on mechanical properties of Schizophyllum commune mycelium sheets. To this end, glutaraldehyde and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) were used as well as extracts of Ligustrum vulgare leaves, and bark of Acacia mearnsii and Caesalpinia spinosa. Untanned sheets had a σ of 7.8 MPa and an ε of 15.2 %, while the best overall combination of strength and elasticity was obtained with 0.1 % glutaraldehyde with a σ of 11.1 MPa and an ε of 14.6 %. Cross-linking also increased enzymatic stability and reduced mycelial water absorption but did not result in increased thermal stability. Fourier transform infrared spectroscopy (FTIR), 1D nuclear magnetic resonance spectroscopy (NMR), and amino acid analysis showed that glutaraldehyde bound both protein amino groups and polysaccharide hydroxyl groups by forming Schiff bases and acetals, respectively. Together, synthetic and vegetable cross-linkers can be used to obtain mycelium materials with leather-like tensile strength.

Investigating the synergistic effect of iodide ion and Michelia alba leaf extract on carbon steel in 0.5M H2SO4

The study examined the inhibitory effect of Michelia alba leaf extract (MALE) on carbon steel (CS) in 0.5M H2SO4 solution. Furthermore, the investigation explored the effect of KI to enhance the protection provided by MALE. The study demonstrates that both MALE and KI have corrosion inhibiting properties on CS in acidic solutions. However, when MALE and KI are combined, they exhibit a greater inhibitory effect. Corrosion inhibition efficiency was limited to 86.55% with 400mg/L MALE. The maximum corrosion inhibition efficiency was 51.84% when 400mg/L KI was used alone. However, when 800mg/L MALE was combined with 400mg/L KI in 0.5M H2SO4 solution, the efficiency increased to 95.02%. This increase can be attributed to the synergistic effect between MALE and KI. The SEM and XPS results further confirmed that the addition of KI could be more effective in preventing the corrosion of CS. The theoretical calculations demonstrate that constituents found in the extract, which are rich in hydroxyl groups, benzene rings, N and S atoms have a higher probability of adsorption onto the CS surface in parallel, thereby increasing the efficiency of corrosion inhibition significantly.

Synthesis, structural characterization, DFT and molecular dynamics simulations of dinuclear (μ-hydroxo)-bridged triethanolamine copper(II) complexes: efficient candidates towards visible light-mediated photo-Fenton degradation of organic dyes.

Multinuclear (di/tri) copper(II) complexes bridged through hydroxyl groups are very interesting coordination complexes owing to their potential applications in various fields. In this work, three novel dinuclear (μ-hydroxo)-bridged copper(II) complexes in the crystal form, namely, [Cu2(3,5-DIFLB)2(H2tea)2](H2O) (1), [Cu2(4-ClB)2(H2tea)2](H2O) (2), and [Cu2(4-ETHB)2(H2tea)2](H2O)2 (3) (where DIFLB = difluorobenzoate, CLB = chlorobenzoate, ETHB = ethoxybenzoate, and H3tea = triethanolamine), were isolated at room temperature using methanol and water in a 4 : 1 v/v ratio as a solvent. Furthermore, all three complexes (1-3) were characterised using spectroscopic (UV-vis, DRS, and FT-IR), electrochemical (CV) and single-crystal X-ray diffraction techniques. Structural insights gained by packing analysis revealed the role of steric constraints of substituents and various non-covalent interactions in lattice stabilization, which were indeed supported by theoretical and molecular electrostatic potential illustrations. Hirshfeld surface analysis provided quantitative verification about various non-covalent interactions (interatomic contacts) involved in the packing of molecules. Interestingly, as a potential application, complexes 1-3 all exhibited remarkable visible light-mediated photo-Fenton degradation of approximately 98% for 50 ppm concentration of organic dyes (fuchsin basic (FB) and methyl orange (MO)) in 90 minutes with the optimized conditions of 1 mg mL-1 of dye solution. In all the cases, dye degradation by these materials was ascribed to the symbiotic relations among the molecular structures of complexes 1-3, which were endowed with various electron-withdrawing and electron-releasing substituents and ionic strength, with respect to the structure, shape and interacting patterns of dye molecules. The adsorption mechanism indicates that various weak interactions between the donor and acceptor groups of complexes and dyes, such as electrostatic, hydrogen bonding, and direct coordination to metal sites, play a crucial role, which is confirmed by molecular dynamics (MD) simulations. Theoretical studies by DFT-based descriptors, molecular electrostatic potentials, and band gaps provided deep insights into various electronic and reactivity parameters. For subsequent processes of dye degradation, complexes 1-3 were stable and recoverable. The successful integration of experimental and theoretical approaches sheds light on copper-based dinuclear stable coordination complexes, showcasing a significant step towards the development of novel heterogeneous photo-Fenton catalysts.

Investigating the microscopic enhancement mechanisms of adsorption-based CO2 capture with Cu-loaded γ−Al2O3 using density functional theory

Transition-metal-loaded γ−alumina (Al2O3) is considered to be an effective adsorbent for CO2 capture, but its microscopic process and mechanisms of CO2 adsorption are not fully understood. To investigate the microscopic enhancement role of Cu atoms in CO2 adsorption, this work compares various adsorption configurations and parameters of CO2 on γ−Al2O3 (110) facets with or without Cu atoms and small Cu cluster loading (Cun (n=1,2,3)/γ−Al2O3) using the first-principles approach. According to the adsorption energy, charge transfer, difference charge density, and other parameters of different configurations, the γ−Al2O3 (110) slab loaded with the Cu atom is found to exhibit enhanced adsorption of CO2 molecules compared to that without Cu loading. Moreover, the surface stability increases with the number of loaded Cu atoms. However, the hydroxyl groups in the active sites partially undermine the adsorption effect during the CO2 adsorption process. The density of states indicates that the doping of Cu atoms in the system creates an orbital peak closer to the Fermi energy level. This facilitates the transfer of charge within the slab, making the activation of CO2 easier and promoting stable adsorption. Finally, the amount of crystal orbital overlap population and crystal orbital Hamilton population shows that the stability of adsorption is due to the formation of C-Cu and C-Al bonds. It is demonstrated that the Cun-loaded γ−Al2O3 (110) slab improves the adsorption performance and contributes to a better understanding of the effect of transition-state metal loaded γ−Al2O3 on CO2 adsorption.

Flavonoid as a Potent Antioxidant: Quantitative Structure-Activity Relationship Analysis, Mechanism Study, and Molecular Design by Synergizing Molecular Simulation and Machine Learning.

In this work, a quantitative structure-antioxidant activity relationship of flavonoids was performed using a machine learning (ML) method. To achieve lipid-soluble, highly antioxidant flavonoids, 398 molecular structures with various substitute groups were designed based on the flavonoid skeleton. The hydrogen dissociation energies (ΔG1, ΔG2, and ΔG3) related to multiple hydrogen atom transfer processes and the solubility parameter (δ) of flavonoids were calculated using molecular simulation. The group decomposition results and the calculated antioxidant parameters constituted the ML data set. The artificial neural network and random forest models were constructed to predict and analyze the contribution of the substitute groups and positions to the antioxidant activity. The results showed the hydroxyl group at positions B4', B5', and B6' and the branched alkyl group at position C3 in the flavonoid skeleton were the optimal choice for improving antioxidant activity and compatibility with apolar organic materials. Compared to the pyrogallol group-grafted flavonoid, the designed potent flavonoid decreased ΔG1 and δ by 2.2 and 15.1%, respectively, while ΔG2 and ΔG3 kept the favorable lower values. These findings suggest that an efficient flavonoid prefers multiple ortho-phenolic hydroxyl groups and suitable sites with hydrophobic groups. The combination of molecular simulation and the ML method may offer a new research approach for the molecular design of novel antioxidants.

Integrated experiments and numerical simulations for chromium (VI) surface complexation in natural unconsolidated sediments

This study focuses on the adsorption and transport of Cr (VI) on natural sediments from Qiqihar, China. Through batch and column experiments, we assessed the adsorption capacities influenced by factors such as contact time, initial concentration, pH, ionic strength, solid-to-solution ratio, coexisting ions in groundwater, sediment characteristics and flow rate. The adsorption kinetics of Cr (VI) follow the pseudo-first-order model well, while the isotherms of all three sediments are accurately represented by the Freundlich model. The adsorption edges reveal a strong pH dependence in Cr (VI) adsorption: the stronger the acidity, the more favorable it is for adsorption. The adsorption capacity decreases with an increasing solid-to-solution ratio, stabilizing at higher ratios. Coexisting ions in groundwater reduce Cr (VI) adsorption in loam under neutral pH. Additionally, Fourier transform infrared spectroscopy (FTIR) results indicate that the hydroxyl group is the primary reactive functional group in all three sediments. X-ray photoelectron spectroscopy (XPS) results further show partial adsorbed Cr (VI) was reduced to Cr (III) by organic matters. However, surface complexation reactions dominate the removal of Cr (VI). On the base above, we introduced a surface complexation model, optimizing equilibrium complexation constants by fitting adsorption edges. Subsequently, reactive transport models incorporating both surface complexation and reduction processes for Cr (VI) were established to simulate column experiments. As the flow rate decreases, the adsorption capacity and the amount of reduction reaction for Cr (VI) increase, while the reduction rate decreases. Specifically, the reduction for Cr (VI) was found to be more significant in loam compared to sand, correlating with the organic matter content. The results emphasize the existence of surface complexation reactions and the role of organic matters in electron transfer. Our study provides significant information for understanding Cr (VI) adsorption and transport behavior in natural aquifer sediments.

Molecular dynamics study of Gr(GO)/C-A-S-H composites at different temperatures: optimization of structural, dynamic and mechanical properties of civil engineering materials

In recent years, composites have been widely used in engineering fields, where nanomaterials such as graphene (Gr) and graphene oxide (GO) have potential advantages as interfacial modifiers in enhancing the properties of composites. However, the relationship between the interfacial structure and the mechanical properties of the nanocomposites is not clear, and the behavior of the composites may differ significantly at different temperatures. This study aims to investigate in depth the interfacial structure, dynamics, and mechanical properties of Gr, epoxy group-containing (-O) and hydroxyl group-containing (-OH) graphene oxide and calcium aluminosilicate hydrate (C-A-S-H) composites at different temperatures using molecular dynamics. The effect of nanomaterial composition on the interfacial chemical bonding network is revealed. The local chemical structures of bridging aluminum [Al(Q2b)] and interlayer aluminum (Alw) show different changes at different temperatures. Elevated temperature promotes the hydrolysis of interlayer water molecules to form hydroxyl groups, which affects the formation of chemical bonding networks.Al(Q2b) favors Gr and C-A-S-H linkages, whereas Alw favors GO and C-A-S-H bonding. Temperature changes lead to different chemical bonding connections and altered atomic motions. At the interface, Al atoms form a more stable chemical bonding network, which improves the interaction strength at the interface. Different composite models exhibited different mechanical properties at high temperatures and introducing epoxy and hydroxyl groups enhanced the plastic deformation of the composites. Structural analyses showed that temperature changes affected the molecular structure and interfacial bonding effects of the composites, which in turn affected the mechanical properties of the materials. At different temperatures, GO-O/C-A-S-H has higher tensile strength and Young's modulus, which can resist the degradation of performance caused by thermal expansion to a certain extent, and ensure the stability and safety of the structure, so it is more practical. These findings provide important insights to deepen the understanding of composite properties and have positive implications for future composite design and applications.

Bile Acid-conjugate as a Promising Anticancer Agent: Recent Progress.

Bile acids have outstanding chemistry due to their amphiphilic nature and have received a lot of interest in the last few decades in the fields of biomedicine, pharmacology, and supramolecular applications. Bile acids are highly sought after by scientists looking for diverse and effective biological activity due to their chirality, rigidity, and hydroxyl group. The hydroxyl group makes it simple to alter the structure in a way that improves bioactivity and bioavailability. Bile acid-bioactive molecule conjugates are compounds in which a bile acid is linked to a bioactive molecule by a linker in order to increase the bioactivity of the bioactive molecule against the target cancer cells. This method has been used to improve the therapeutic efficacy of cytotoxic drugs while reducing their adverse side effects. These new bile acid conjugates are gaining attention because they overcome bioavailability and stability issues. The design, synthesis, and anticancer effectiveness of various bile acid conjugates are discussed together with recent advances in understanding in this review.

Low-energy micron dispersion of entangled polymers based on phase inversion composition of emulsion

This article aims to propose a low-energy method for micron dispersion of entangled polymers. We chose Ethylene-Propylene-Diene Monomer (EPDM) as the entangled polymer and acrylic esters as the dispersants to prepare the organic dispersion of the entangled polymer based on the theory that in-situ polymerization of acrylic esters had the higher solubility parameter than the original monomer. The dispersion process of entangled polymer was similar to the phase inversion of emulsion due to the maximum viscosity and minimum interfacial tension at the point of dispersion. Specifically, the average diameter of the dispersed entangled polymer was 5-6 μm. The system could still maintain excellent dispersion stability without additional dispersants. Rheology characterized that the introduction of aliphatic isocyanate derivatives reacting with hydroxyl groups in the polyacrylate to form the cross-linked skeleton could enhance the stability of the system. Excitingly, this organic dispersion allowed flexible printed circuit to fold at any angle and direction when used as the coating, and the coating still maintained excellent dispersibility, flexibility, insulation, and adhesion after aging tests. This low-energy method for micron dispersion of entangled polymers could expand their applications in coatings and other fields while maintaining their own characteristics.

Chromatographic evaluation and application of nitrogenous heterocyclic ring-bonded stationary phase in hydrophilic interaction liquid chromatography

Hydrophilic interaction liquid chromatography (HILIC) based on polar stationary phases has vital research significance in the separation of polar compounds. Numerous HILIC stationary phases with different structures have been developed, which do not have universal properties and broad selectivity, making it a challenge to select the suitable column based on the properties of the samples. Consequently, it is particularly important to develop a bonded phase capable of separating a wide variety of samples, while having enhanced retention, improved selectivity, symmetric peak shape and good stability. Herein, a novel nitrogen-containing heterocyclic bonded phase with multiple functionalities, such as thioether, amino and hydroxyl groups (named AMTA) was employed as HILIC stationary phase. Detailed chromatographic evaluations were carried out, and the results showed that it was superior to other hydrophilic chromatographic columns in terms of selectivity, peak shapes and practical sample separation. Lastly, it has been verified that AMTA exhibited high orthogonality with the XBridge C18 column of reversed-phase liquid chromatography (RPLC) mode. In summary, we anticipate our assay to be instructive to other researchers in developing the HILIC stationary phase.

Fabrication of ultra-permeable membranes with antibiofouling capability by incorporating bifunctionalized zeolite

Poor water permeance and biofouling significantly limit the application of nanofiltration (NF) membranes in wastewater treatment and seawater desalination. Herein, bifunctionalized FAU-Ag-OH zeolites, featuring abundant hydroxyl groups and silver ions on their surface, were designed and incorporated into polyamide (PA) layer of a thin-film nanocomposite (TFN) membrane, effectively enhancing the antibiofouling properties and water permeance of membrane. The plentiful hydroxyl groups and well-dispersed silver ions on the bifunctionalized FAU-Ag-OH zeolites impart the membrane with more negative surface charge, increased hydrophilicity, and superior antibiofouling property. Additionally, the doped FAU-Ag-OH zeolites can retard the diffusion of piperazine during interfacial polymerization (IP) process and have improved chemical compatibility with polymers, which results in desirable membrane structure. Consequently, the optimal M–0.05 membrane containing FAU-Ag-OH zeolites exhibited a 2.3-fold increase in water permeance (18.8 ± 2.0 L m−2 h−1 bar−1) and enhanced antibiofouling ability (with antibacterial efficiency up to 95.4 % and flux recovery ratio up to 85 %) compared with the TFC membrane. The successful fabrication of such membrane with enhanced antibiofouling properties and enhanced water permeance is expected to promote the application of NF membranes in water treatment.

Significantly enhanced high-temperature energy storage performance for polymer composite films with gradient distribution of organic fillers

Film capacitors as one of the most important electronic devices are heading in large capacity, heightened integration and excellent extreme-condition tolerance, which faces the challenges in maintaining outstanding performance under harsh conditions of high temperature and large electric field. Nonetheless, polymer capacitive films, which are renowned for their exceptional thermal stability, experience an escalation in conduction losses at elevated temperatures, resulting in degradation of energy storage performance. This study presents the gradient distribution of organic fillers content in all-organic polymer capacitive films utilizing electrospinning technique, the significantly improved high-temperature energy storage performance has been achieved. Glucose (GLC), a weak polar molecule rich in hydroxyl groups, is blended with the most promising polyetherimide (PEI). Experimental and theoretical calculations confirm that the formed hydrogen bond between GLC and PEI acts as a trapping site for capturing carriers and suppressing conduction losses. Furthermore, the spatial distribution of organic fillers was designed on the basis of direct mixing. The results demonstrate that the gradient composite film introduces interlayer interfacial polarization, while the dielectric mismatch between adjacent layers increases the height of potential barriers for the charge carriers across the interfaces, thereby achieving a synergistic enhancement of dielectric response and insulation strength. The maximum discharge energy density of 6.52 J/cm3 with an efficiency of 85.6 % has been achieved at 150℃ for the modified capacitive films. This work establishes a decoupling relationship between permittivity and electric breakdown strength, offering insights for the advancement of polymer films with outstanding energy storage capabilities in extreme environments.