Wide pH Range Research Articles

Facile Synthesis of a Layered Bismuth-Based MOF With Superhydrophobic-Oleophilic Property and High Oil-Water Separation Performance.

Metal organic frameworks (MOFs) are a class of potential superhydrophobic-oleophilic materials. The organic ligands in superhydrophobic MOFs usually contain long alkyl chains, fluorine groups or aromatic rings with large π conjugation, the preparation of which suffers from high cost, complex operation and so on. In addition, the topological structure of MOFs plays an important role in the hydrophobicity, which may be ignored previously. Here we report a superhydrophobic-oleophilic MOF (BiPPA2) obtained by a facile and fast method, which not only displays a large water contact angle of up to 163° and a small sliding angle of nearly equal to 0°, but also exhibits high sorption capacity for multiple oils and organic solvents, well reusability and high oil retention. In addition, BiPPA2 is stable in a wide pH range (0.5-11.0). Finally, the single crystal structure of BiPPA2 is resolved to reveal the intrinsic reason for the super-hydrophobicity. This work may inspire the further design of pristine superhydrophobic MOFs based on a simple method, which enriches the family of superhydrophobic MOFs and has great significance for practical applications.

High Performance and Selective Sequestration of Cd(II) from Water by Layered Thiophosphate.

The extensive use of toxic cadmium (Cd) in energy conversion and industrial applications ranging from solar cells and battery appliances to paints and pigments contaminates water bodies. However, the upper limit of Cd contamination in drinking water is to be only 3 ppb by the WHO and 5 ppb by the USA-EPA, which underscores the need for cost-effective, efficient, and ppb level capture of Cd from contaminated water. Leveraging the selectivity due to Lewis's hard-soft acid-base (HSAB) theory, we have achieved swift and highly selective capture of Cd(II) ions from aqueous mediums using layered potassium manganese thiophosphate (K-MnPS3). K-MnPS3 effectively removes Cd(II) ions from extremely dilute aqueous solutions (ppb levels), achieving a maximum sorption capacity of 405.43 mg/g and a removal rate exceeding 97% within 20 min. Even in the presence of competing ions such as Na+, Mg2+, Ca2+, and Pb2+, K-MnPS3 remains selective. Additionally, it operates efficiently across a wide pH range (1.78-11.19) with a high distribution coefficient (∼104 mL/g). Breakthrough experiments using a 1 wt % K-MnPS3 and 99 wt % sand column showed complete breakthrough of Cd(II) after 62 h, leading K-MnPS3 as a promising candidate for Cd(II) removal from industrial effluents.

Recyclable wood-structured bimetallic carbon aerogel for high-performance bulk catalytic antibiotic decomposition

Harnessing renewable low-cost, bulk wood-structured materials with highly porous, anisotropic and compressible properties that fulfills sustainable water purification is imperative yet still challenging to push forward a circular bioeconomy. In this work, a bimetallic Fe-Co implanted, N-doped wood carbon aerogel (Fe-Co/NWCA) is constructed to guarantee the facile regeneration in high-performance catalytic antibiotic decomposition via activating peroxymonosulfate (PMS). A rapid, reversible and excellent tetracycline (TC) elimination performance (∼90% in 12 min) within a wide pH range of 3–11 is achieved by Fe-Co/NWCA-mediated system. Importantly, the as-prepared hydrophilic Fe-Co/NWCA not only delivers a favorable robustness to interfering anions (e.g., Cl−, H2PO4− and HCO3−), but also presents a superior recyclability with over 90% retention after the fourth cycling operation via a convenient squeezing behavior. Integration of radical quenching experiments and electron paramagnetic resonance demonstrates the participation of reactive oxygen species (ROS) into catalytic TC oxidation, wherein the dominant contributor is 1O2 followed by O2•‾, SO4•‾ and •OH. As an important non-radical route, the directly interfacial electron transfer is confirmed by electrochemical measurements and density-functional-theory computations. In the context of activating PMS, the multi-valent Fe, Co-coordinated species function as the redox reactive site to trigger diversiform ROS with accelerated kinetics, while N, O-associated surface defects and unsaturated functional groups (e.g., −COOH and ketonic C=O) contribute to the 1O2 formation and electron shuttling. This universal approach paves a critical avenue to manufacture the reactive wood-based aerogels with hierarchical microchannels in the practical pollutant remediation, shedding the valuable insights on multifunctional biomass-water nexus.

Isolation and characterization of a multidrug-resistant Staphylococcus aureus infecting phage and its therapeutic use in mice.

In recent years, the emergence of multidrug-resistant bacteria has limited the selection of drugs for treating bacterial infections, reduced clinical efficacy, and increased treatment costs and mortality. It is urgent to find alternative antibiotics. In order to explore a new method for controlling methicillin resistant Staphylococcus aureus (S. aureus) , this study isolated and purified a multi drug resistant S. aureus broad-spectrum phage JPL-50 from wastewater. JPL-50 belongs to the Siphoviridae family after morphological observation, biological characterization, and transmission electron microscopy (TEM) fragmentation spectrum analysis. It can cleave 84% of tested S. aureus (168/200) , in which 100% of tested mastitis-associated strains (48/48) and 72.04% of MRSA strains (67/93) were lysed. In addition, it has an optimal growth temperature of about 30°C, a high activity within a wide pH range (pH 3-10) , and an optimal multiplicity of infection of 0.01. The one-step growth curve shows a latent time of 20 minutes, an explosive time of 80 minutes. JPL-50 was 16, 927 bp in length and was encoded by double-stranded DNA, with no genes associated with bacterial resistance or virulence factors detected. In a therapeutic study, injection of the phage JPL-50 once and for 7 times in 7 days protected 40% and 60% of the mice from fatal S.aureus infection, respectively. More importantly, JPL-50-doxycycline combination could effectively inhibit host S.aureus in vitro and reduce the use of doxycycline within 8 hours. In conclusion, the bacteriophage JPL-50 has a wide lysis spectrum, high lysis rate, high tolerance to extreme environments, and moderate in vivo activity, providing ideas for developing multidrug-resistant S. aureus infections.

MoS2 coupled with ball milling co-modified sludge biochar to efficiently activate peroxymonosulfate for neonicotinoids degradation: Dominant roles of SO4•-, 1O2 and surface-bound radicals

An efficient catalyst of molybdenum disulfide (MoS2) coupled with ball milling modified sludge biochar (BMSBC) was prepared to efficiently activate peroxymonosulfate (PMS) for neonicotinoids elimination. As expected, 95.1% of imidacloprid (IMI) was degraded by PMS/BMSBC system within 60 min and it was accompanied by the outstanding mineralization rate of 71.9%. The superior pore structures, rich defects, oxygen-containing functional groups and grafted MoS2 on BMSBC offered excellent activation performance for PMS. The influencing factor experiments demonstrated that PMS/BMSBC system performed high anti-interference to wide pH range and background constituents (e.g., inorganic ions and humic acid). Quenching experiments and electron paramagnetic resonance analysis revealed that SO4•−, 1O2, and surface-bound radicals played critical roles in IMI degradation. Electron donors on biochar activated PMS , producing surface radicals. The lone pair electrons within the Lewis basic site of C=O on BMSBC enhanced PMS decomposition by facilitating the cleavage of the -O-O- bond in PMS to release 1O2. The activation process of PMS by MoS2 accelerated the oxidation of Mo (IV) to Mo (VI) to generate SO4•−. Based on the transformed products (TPs), four degradation pathways of IMI in PMS/BMSBC system were suggested, and all TPs toxicity levels were lower than that of IMI by ECOSAR analysis. Additionally, BMSBC exhibited outstanding sustainable catalytic activity towards PMS activation with the well accepted degradation rate of 71.3% for IMI even after five reuse cycles. PMS/BMSBC system also exhibited satisfactory degradation rates (>71.8%) for IMI in various real waters (e.g., sewage effluent, and livestock wastewater). Furthermore, PMS/BMSBC system also offered a favorable broad-spectrum elimination performance for other typical neonicotinoids (e.g., thiamethoxam, clothianidin, thiacloprid) with the degradation rates over 98%. This study has developed a desirable neonicotinoids purification technology in view of its high degradation/mineralization rate, outstanding detoxification performance, satisfied anti-interference to ambient conditions and sustainable sludge management.

Tough supramolecular hydrogels of poly(N,N-dimethylacrylamide)-grafted poly(methacrylic acid) with cooperative hydrogen bonds as physical crosslinks.

Incorporating associative interactions as the energy dissipation units has been recognized as an effective strategy to develop tough hydrogels. For hydrogen-bond associations, however, it is highly challenging to stabilize them under aqueous conditions. Although affording cooperativity can enhance and stabilize the hydrogen bonds, it usually requires stepwise polymerization to form these cooperative associations between different polymers and networks. Here, we report a series of tough supramolecular hydrogels with robust hydrogen-bond associations between grafted polymers that are synthesized by polymerization of a macromonomer of poly(N,N-dimethylacrylamide) (PDMAA) and a small monomer of methacrylic acid. The grafted chains of PDMAA form cooperative hydrogen bonds with the main chain of poly(methacrylic acid) (PMAAc), forming supramolecular hydrogels with high toughness and good stability. The tough and stiff hydrogels are in a glassy state, exhibit forced elastic deformation at room temperature, and remain stable over a wide pH range. In contrast, hydrogels prepared by the copolymerization of DMAA and MAAc are swollen and weak in water due to the lack of successive hydrogen donor/acceptor units and the absence of cooperative hydrogen bonds. In addition, these tough hydrogels exhibit good recyclability and shape memory properties, owing to the supramolecular nature of the network and the temperature-dependent mechanical properties. The influence of polymer structure on the associative interactions and macroscopic properties of the hydrogels should be informative for the design of tough soft materials with versatile applications.

Enhanced Fenton-like process on Co9S8 catalyst with Mixed-Valence Cobalt(0)/Cobalt(Ⅱ)

Peroxymonosulfate (PMS)-based Fenton-like reactions have great potential to revolutionize wastewater treatment, but achieving highly efficient decontamination at low chemical input remains extremely challenging. In this study, a carbon carrier-supported Co9S8 catalyst with Mixed-Valence Cobalt(0)/Cobalt(Ⅱ) was prepared, which enables 70.72 % PMS decomposition-rate and complete, highly efficient tetracycline (TC) removal. Through the cyclic conversion pathways of polyvalent cobalt and the auto-decomposition of PMS, which produced SO4•-, 1O2, •OH, and high-valence metals, the material’s efficiency in degrading TC through PMS activation was effectively enhanced (99.92 %). S2-, as one of the active sites, not only promotes the participation of Co3+/Co2+/Co0 in the generation of reactive oxygen species but also significantly facilitates electron transfer to further increase the catalytic reaction rate. Through metal-chelating agents, it is illustrated that Co2+ directly activates PMS to produce reactive oxygen species (ROS), while Co3+ promotes cycling. The normalized kinetic constant of Co9S8/Co-C (105.6 min−1M−1) was even four times larger than that of Co9S8 (26.4 min−1M−1). Co9S8/Co-C exhibited rapid degradation over a wide pH range and extensive cycling experiments, demonstrating its versatility and stability in various environments. Possible degradation pathways were speculated using liquid chromatography-mass spectrometry (LC-MS). Toxicological evaluations and mung bean germination toxicity tests indicated that the Co9S8/Co-C+PMS system effectively reduced toxicity. It enables the complete degradation of TC while remarkably reducing the toxic intermediates, ensuring that the catalyst is suitable for wastewater treatment applications.

Peroxymonosulfate activation by CoO@C catalyst from integrated recycling of spent lithium-ion battery: Performance and mechanism

Developing low-cost, highly active transition metal-based catalysts for peroxymonosulfate (PMS) activation is essential but remains challenging. Herein, we proposed a novel “waste-to-energy” strategy to derive an effective PMS activator (CoO@C) by integrally utilizing the abundant Co content in the cathodes and the defective structure of anode graphite from spent lithium-ion batteries (LIBs). The CoO@C/PMS system could completely degrade atrazine (ATZ) within 15 min, along with a robust resilience to coexisting substrate and a wide pH range of 5.0–11.0. Through quenching experiments and electron paramagnetic resonance (EPR), •OH was identified as the primary reactive oxygen species (ROS) responsible for ATZ degradation. Furthermore, electron transfer between the catalyst and PMS was examined via density functional theory (DFT) calculations to elucidate the activation mechanism. The Fukui index pinpointed the vulnerable sites of ATZ, offering insights into the possible degradation pathways along with UHPLC-MS analysis. Furthermore, CoO@C was fixed on a polyethersulfone (PES) membrane for continuous degradation of ATZ, which maintained a degradation efficiency exceeding 90 % after treating 6 L of wastewater. This research provided valuable insights into the preparation of metal-based catalysts for advanced oxidation processes and achieved the sustainable utilization of spent LIBs.

Genome Analysis of a Potential Novel Vibrio Species Secreting pH-and Thermo-Stable Alginate Lyase and Its Application in Producing Alginate Oligosaccharides

Alginate lyase is an attractive biocatalyst that can specifically degrade alginate to produce oligosaccharides, showing great potential for industrial and medicinal applications. Herein, an alginate-degrading strain HB236076 was isolated from Sargassum sp. in Qionghai, Hainan, China. The low 16S rRNA gene sequence identity (<98.4%), ANI value (<71.9%), and dDDH value (<23.9%) clearly indicated that the isolate represented a potential novel species of the genus Vibrio. The genome contained two chromosomes with lengths of 3,007,948 bp and 874,895 bp, respectively, totaling 3,882,843 bp with a G+C content of 46.5%. Among 3482 genes, 3332 protein-coding genes, 116 tRNA, and 34 rRNA sequences were predicted. Analysis of the amino acid sequences showed that the strain encoded 73 carbohydrate-active enzymes (CAZymes), predicting seven PL7 (Alg1–7) and two PL17 family (Alg8, 9) alginate lyases. The extracellular alginate lyase from strain HB236076 showed the maximum activity at 50 °C and pH 7.0, with over 90% activity measured in the range of 30–60 °C and pH 6.0–10.0, exhibiting a wide range of temperature and pH activities. The enzyme also remained at more than 90% of the original activity at a wide pH range (3.0–9.0) and temperature below 50 °C for more than 2 h, demonstrating significant thermal and pH stabilities. Fe2+ had a good promoting effect on the alginate lyase activity at 10 mM, increasing by 3.5 times. Thin layer chromatography (TLC) and electrospray ionization mass spectrometry (ESI-MS) analyses suggested that alginate lyase in fermentation broth could catalyze sodium alginate to produce disaccharides and trisaccharides, which showed antimicrobial activity against Shigella dysenteriae, Aeromonas hydrophila, Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli. This research provided extended insights into the production mechanism of alginate lyase from Vibrio sp. HB236076, which was beneficial for further application in the preparation of pH-stable and thermo-stable alginate lyase and alginate oligosaccharides.

Novel Insights in the Application of Probiotic Yeast Saccharomyces boulardii in Dairy Products and Health Promotion

Probiotic organisms are increasingly being incorporated into foods in order to develop products to prevent and reduce many diseases. Saccharomyces boulardii, a probiotic yeast with unique properties, such as viability over a wide pH range, antibiotic resistance, and the ability to reach a steady state, has an advantage over bacterial probiotics. The present review highlights the potential application of S. boulardii in functional fermented dairy products and the genetic engineering of this probiotic microorganism as a therapeutic agent for the treatment of various infectious diseases. It was found that probiotic yeast stimulates the growth of lactic acid bacteria in dairy products, creating favorable conditions and positively affecting the product’s sensory characteristics. Moreover, its viability of more than 106 cfu/mL at the end of the yogurt shelf life confirms its probiotic effect. On the other hand, there is a growing interest in the design of probiotic strains to improve their characteristics and fill existing gaps in their spectrum of action such as the inhibition of some bacterial toxins, as well as anti-inflammatory and immunomodulatory effects. The strengthening of immune functions and effective therapies against various diseases by S. boulardii was confirmed. However, considering this yeast species’ potential, further research is necessary to accurately determine the functional properties in terms of incorporation into food matrices and from the aspect of health and well-being claims.

Cyano-functionalized porous hyper-crosslinked cationic polymers for efficient preconcentration and detection of phenolic endocrine disruptors in fresh water and fish

Sensitively analyzing phenolic endocrine-disrupting chemicals (EDCs) in environmental substrates and aquatic organisms provides a significant challenge. Here, we developed a novel porous hyper-crosslinked ionic polymer bearing cyano groups (CN-HIP) as adsorbent for the highly efficient solid phase extraction (SPE) of phenolic EDCs in water and fish. The CN-HIP gave an excellent adsorption capability for targeted EDCs over a wide pH range, and the adsorption capacity was superior to that of several common commercial SPE adsorbents. The coexistence of electrostatic forces, hydrogen bond, and π-π interactions was confirmed as the main adsorption mechanism. A sensitive quantitative method was established by coupling CN-HIP based SPE method with high-performance liquid chromatography for the simultaneously determining trace bisphenol A, bisphenol F, bisphenol B and 4-tert-butylphenol in fresh water and fish. The method afforded lower detection limits (S/N = 3) (at 0.03–0.10 ng mL−1 for water and 0.8–4.0 ng g−1 for fish), high accuracy (the recovery of spiked sample at 88.0%–112 %) and high precision (the relative standard deviation < 8.5 %). This work provides a feasible method for detecting phenolic EDCs, and also opens a new perspective in developing functionalized cationic adsorbent.

Development of a Rapid Fluorescence Probe for the Determination of Aqueous Hypochlorite

Chlorine interacts with aqueous environments, including the mucosa and alveolar fluid in the lungs, causing its the immediate transformation to hypochlorous acid (HClO) and hydrochloric acid (HCl) which induces cellular damage and may produce systemic toxicity. There are multiple techniques to monitor hypochlorite (HClO/ClO−) from various matrices, however, they each have significant disadvantages, including limited sensitivity, complexity, and slow response. In this study, we developed a water-soluble fluorescein-based probe, called fluorescein thioacid (FSH), for the rapid and sensitive detection of HClO/ClO− in aqueous solutions via oxidation of FSH to produce fluorescein. FSH was synthesized via a simple, one-step procedure and exhibited excellent selectivity for ClO−, maintaining 82% signal stability for 24 h. FSH performed well over a wide pH range (4–10; optimum pH of 4), produced a linear range from 1 to 100 µM, and had a detection limit of 100 nM. The probe was able to accurately quantify HClO/ClO− concentrations in tap water (13.8 μM) and swimming pool water (56.9 μM) samples. Overall, FSH is simple to synthesize, highly selective, highly sensitive, has excellent water solubility, and produces a fast response for monitoring of aqueous ClO− levels.

Stable Magnetite@La-Fe Oxide Core-Shell Nanostructures Prepared via Lattice Lock for Reusable Extraction of Phosphate Anions.

Stable magnetic core-shell nanostructures are developed by lattice locking lanthanide-iron (La-Fe) oxide shells with magnetite cores to prevent the release of La from the surfaces of the magnetite nanostructures. The resulting core-shell nanostructures demonstrate excellent outstanding regeneration performance and high adsorption capacity for phosphate (115 mg P·g-1). These nanostructures release minimal La from the magnetite core surfaces after adsorbent regeneration, with a La loss of only 20% compared to the control sample, Mag@La(OH)3. La3+ ions were released at concentrations ranging from 1 to 2.3 μg·L-1 at pH levels of 4 to 8, which is within the metal content range found in natural aquatic environments. These results demonstrate the high stability of the nanostructures after regeneration. Furthermore, the adsorbent exhibits high extraction capacity across a wide pH range of 4 to 10 and performs well even in the presence of interfering anions at phosphate-to-anion molar ratios of 1:5, 1:25, and 1:100. Microscopic and spectroscopic analyses reveal that the primary extraction mechanism of phosphate in the La-containing shells is surface precipitation. This approach not only improves the use of magnetic core-shell nanostructures as adsorbents but also demonstrates the creation of a broad range of stable magnetic functional materials for diverse applications.

Mechanistic insights into selenite and selenate immobilization using brucite-rich magnesium precipitate derived from seawater electrochlorination facility

This study explored the application of magnesium precipitate (MP) obtained from seawater electrochlorination storage tanks as an innovative and sustainable adsorbent for Se(IV) and Se(VI) in water. Initially, the collected pristine MP mainly consisted of the low crystalline Mg(OH)2 (brucite) phase. Subsequently, the MP underwent calcination (CMP), and analyses via scanning electron microscopy (SEM) and X-ray diffraction (XRD) confirmed an improved crystallinity, displaying a typical hexagonal plate structure in the aqueous phase. Notably, the CMP exhibited a significant adsorption capacity (qm: 85.0 mg/g) for Se(IV), while the adsorption capacity for Se(VI) was lower, determined as 3.0 mg/g using the Langmuir adsorption model. Se(IV) adsorption remained relatively consistent across a wide pH range and ionic strength in the presence of competing anions. In contrast, Se(VI) adsorption varied under the same conditions. This differing adsorption behavior of Se(IV) and Se(VI) on CMP could be ascribed to different mechanisms: inner-sphere predominant surface complexation for Se(IV) and outer-sphere complexation for Se(VI). These mechanisms were confirmed via X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), XRD, and SEM analyses, and surface complexation modeling (PHREEQC–PEST) of the batch experimental results. In conclusion, these findings underscored the potential utility of MP as an effective adsorbent for selenium, positioning it as an environmentally sustainable and significant novel material. Furthermore, the study offered mechanistic insights into the interaction between CMP, Se (IV), and Se(VI) in the aqueous phase.

Ionic liquid-triggered charge regulation of polydopamine-based surface for antibacterial nanofiltration

The charged surfaces with desirable performance are of high concern in membrane separation but there exist challenges to tailor them over a task-specific range. Herein, we propose an ionic liquid (IL)-triggered charge regulation strategy for polydopamine (PDA)-based surfaces by tuning the number and position of amino groups of ILs. By strategically manipulating the location of amino groups in either the anion, cation, or both, we realize a complete inversion in the surface charge nature of PDA coatings from highly negative to negative and even highly positive (zeta potential: −25 mV to +25 mV). This charge inversion triggered by IL is attributed to both the number of protonable groups and shielding effect provided by counter ions. Such charge flip enhances Donna effect when the PDA/IL coatings serve as the skin layer of nanofiltration membranes, thereby enabling high rejection to both negative and positive target molecules (i.e., chlorogenic acids at various pH). Despite charge regulation, ILs with dual amino groups cross link the PDA aggregates, largely narrowing the pore size distribution of the skin layer. The IL cross-linked PDA skin layer with uniform pores thus shows a nearly 100 % rejection to the target solutes. Meanwhile, the IL synchronously endow the PDA coatings with tunable charge characteristics, imidazolium functional groups and exceptional superoleophobicity, compensating for the originally inferior antibacterial activity of membranes in a wide pH range.

Biocontrol of citrus fungal pathogens by lipopeptides produced by Bacillus velezensis TZ01.

Citrus diseases caused by fungal pathogens drastically decreased the yield and quality of citrus fruits, leading to huge economic losses. Given the threats of chemical pesticides on the environment and human health, biocontrol agents have received considerable attention worldwide as ecofriendly and sustainable alternative to chemical fungicides. In the present study, we isolated a Bacillus velezensis strain TZ01 with potent antagonistic effect against three citrus pathogenic fungi: Diaporthe citri, Colletotrichum gloeosporioides and Alternaria alternata. The culture supernatant of this strain exhibited remarkable antifungal activity on potato dextrose agar plates and detached leaves of five citrus varieties. Treatment with TZ01 culture supernatant obviously affected the hyphal morphology and caused nucleic acid leakage. The crude lipopeptides (LPs) extracted from the culture supernatant were found as the major active ingredients, and could maintain the activity under a wide range of temperature and pH and ultraviolet radiation. Furthermore, the type of LPs, produced in vitro, were explored. Whole-genome sequencing of TZ01 revealed secondary metabolite gene clusters encoding synthetases for non-ribosomal peptides and polyketide production, and gene clusters responsible for the synthesis of three important LPs (surfactin, iturin, and fengycin) were identified in the genome. The liquid chromatography-mass spectrometry analysis confirmed the presence of various homologs of surfactin A, bacillomycin D, and fengycin A in the extracted LPs. Taken together, these results contribute to the possible biocontrol mechanisms of B. velezensis strain TZ01, as well as providing a promising new candidate strain as a biological control agent for controlling citrus fungal pathogens.

Synergistic Heterostructural Interface of CoP and WC for High-Performance Wide pH-Universal Hydrogen Evolution Electrocatalysis

The development of cost-effective catalysts with high activity and stability over a wide pH range is urgent, but there are great challenges in the selection and design of catalyst materials. In this work, cobalt phosphide nanoparticles were modified onto tungsten carbide nanowire arrays (CoP@WC/CC) on carbon cloth substrate by a two-step method. The construction of CoP@WC heterostructure results in the downward shift of the d-band center, which optimizes the adsorption energy of catalyst and reaction intermediates. Meanwhile, the synergistic effect of CoP and WC contributes to the alkaline HER kinetic process. In addition, binder-free self-supporting nanoarray have excellent electrical conductivity, large specific surface area and strong structure, which is conducive to charge/matter exchange and catalyst stability. The results show that CoP@WC/CC can effectively drive HER over a wide pH range and exhibit better catalytic performance than the single component control sample. In 0.5 M H2SO4 and 1 M KOH, CoP@WC/CC can drive the current density of 10 mA cm-2 with only 52 and 70 mV, while showing excellent stability without obvious performance degradation during 100 hours of constant current test. A proton exchange membrane water electrolysis (PEMWE) using CoP@WC/CC catalyst operates stably for 200,000 s at 30 mA cm-2. This study provides a new reference for the design and development of high efficiency, low cost and wide pH-universal hydrogen evolution electrocatalysts.

Vertically-stacked W/W2C heterojunctions with high electrocatalytic capability for the hydrogen evolution reaction in a wide pH range

The hydrogen evolution reaction (HER) in water splitting is among the foremost methods to produce clean and green hydrogen from renewable sources. The practical use of the HER technology is however hindered by the high price and/or the relatively low efficiency of the currently used catalysts. Herein, we report a heterostructured W/W2C electrocatalyst featuring vertically stacked interfaces and embedded in N-doped porous graphitic carbon (denoted as W/W2C@N-PGC) as a high-performance electrocatalyst for the HER in a wide pH range. The catalyst synthesis, accomplished through a straightforward one-pot method, is both facile and highly efficient involving freeze-drying a suspension of the starting materials followed by pyrolyzing the obtained dry gel. Density functional theory calculations revealed the crucial role of the W/W2C heterojunction in promoting the two key steps of the HER, viz. HOH bond scission and H2 emission. Electrochemical data confirmed the excellent electrocatalytic capability of W/W2C@N-PGC towards the HER process in a wide pH range including alkaline, acidic, and neutral electrolytes. In 1.0 M KOH, we measured a low overpotential of 102 mV to drive a current density of 10 mA cm−2; a long-term stability (up to 24 h) was also realized. The data presented in this work highlight the importance of electrocatalysts with heterojunctions for the HER and the methodology presented in this work may be extended to other contemporary energy-related technologies such as CO2 reduction, oxygen evolution, and oxygen reduction reactions.

Introducing Macrocyclic Glycopeptide Columns as Unique Achiral Stationary Phases: Insights from Hydrophobic Subtraction Model and In-Silico Modeling

BackgroundThe need for stationary phases with unique selectivity in reversed-phase liquid chromatography has been of utmost importance to chromatographers for advancing the analysis of complex samples. Macrocyclic glycopeptide based stationary phases have been widely used for chiral separations with different chromatographic modes such as normal phase, reversed phase, and supercritical fluid chromatography. Given the multimodal retention mechanisms namely π-π complex interaction, hydrogen bonding, dipole-dipole interaction, and strong coulombic interactions by which analytes are separated using the macrocyclic glycopeptides, these stationary phases are expected to provide novel selectivity when used under the reversed phase for achiral separations. ResultsHerein, for the first time we have conducted a systematic study using the improved hydrophobic subtraction model (HSM) which incoporates dipole-dipole interactions to demonstrate the novel selectivity offered by four different macrocyclic glycopeptide based stationary phases, namely NicoShell, TeicoShell, TagShell, and VancoShell. A comparison of the HSM parameters for these columns has been made with 551 commercially available reversed phase stationary phases and the differences in the values point to the importance of adding these columns to the already existing arsenal. These stationary phases offer separations over a wide range of pH and show variability in selectivity depending on the pH of the mobile phase which make them versatile for method development in the reversed phase mode. Additionally, we have provided an actual example of a separation from an Amgen discovery project using the VancoShell column aided by computer-assisted modelling. SignificanceThis is the first report characterizing macrocyclic glycopeptides as achiral RPLC applications. The selectivity of these stationary phases was found to be unique when compared to other commercially available stationary phases thereby acting as their own unique class of columns. The unique selectivity of the columns enabled separation of complex pharmaceutical samples.

A New type of Pseudomonas aeruginosa Phage with Potential as a Natural Food Additive for Eradicating biofilms and Combating Multidrug-Resistant Strains

Pseudomonas aeruginosa is a biofilm-forming bacterial pathogen with multidrug resistance that leads to serious foodborne illnesses. Bacteriophages as alternatives for controlling P. aeruginosa and its biofilms are of great interest, particularly in the food industry. This study report, a new type of P. aeruginosa specific phage named vB PaeM HUST 1 and evaluated antibacterial and biofilm reduction to use alternative as an additive in food industry. vB PaeM HUST 1 showed excellent specificity and selectivity in host cell lysis and stability over a wide range of pH (3-10) and temperature (4-45 °C). Transmission electron microscopy revealed that the phage had a head with a long tail (head: 146.65 nm × 133.32 nm, tail: 199.98 nm); hence, it belongs to the subfamily Straboviridae. The 276114 bp vB PaeM HUST 1 genome encodes 360 ORFs, 7 tRNAs, and an average G+C content of 36.92%. In addition, they exhibited low lipopolysaccharide (LPS) levels at a concentration of 0.133U/mL, with a phage titer of 1.14×109 PFU/mL and no cytotoxicity. vB PaeM HUST 1 efficiently degraded over 95% of the biofilm within 8 h and was highly effective against P. aeruginosa in both milk and beef, with significant reductions of 68.34% and 92% in bacterial concentration after 12 and 24 h of treatment, respectively, with complete eradication achieved after 36 h. Therefore, vB PaeM HUST 1 phage has unique characteristics and can be used as a novel additive to control P. aeruginosa in food matrices.