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.

Characterization of probiotic strains of Bacillus sp. from fermented palm wine (Nypa fructicans sp.) and exploration of cellulolytic potential for use as an addition in animal feed.

The main objective of this study was to assess cellulolytic probiotic strains from traditional fermented beverages such as palm wine in order to supplement the animal feed and strengthen the gut health of the animal for better digestibility and absorption. In the present study, different types of microbes were isolated from traditionally prepared palm wine and analyzed for their probiotic nature. For any microbe to be probiotic in nature, it has to sustain the harsh conditions of the human gastrointestinal tract such as acid tolerance, bile tolerance at the lower range of pH, and other properties like auto aggregation test, cell surface hydrophobicity test with non-polar hydrocarbons for evaluating its capabilities to adhere to the intestinal cells and antimicrobial nature against pathogens. Bacillus mycoides strain PR04 and Bacillus subtilis strain PR21 were found to be resistant to acid and bile in simulated artificial gastrointestinal tract model, found to be than 55% hydrophobic with xylene and n-hexadecane and also showed antimicrobial activity greater towards pathogenic strains like Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Salmonella typhimurium respectively. The cellulolytic activity of the isolates PR04 and PR21 was evaluated in (0.2-2) % CMC (carboxymethyl cellulose) plate. Bacillus mycoides PR04 and Bacillus subtilis PR21 could degrade carboxymethyl cellulose, filter paper, and sugarcane bagasse. The degradation of sugarcane bagasse was confirmed by Scanning electron microscopy and filter paper degradation after 4days of incubation at 37°C. Cellulase gene of the identified Bacillus sp. strains was amplified by primers CF5'-ACAGGATCCGATGAAAACGGTCAATTTCTATTTT-3' and CR5'-ACTCTCGAGATTGGGTTCTGTTCCCAAT-3'. This study proposes potential probiotic Bacillus mycoides PR04 (Accession no. OR625070) and Bacillus subtilis PR21 (Accession no. OR625072) in the application as an animal feed additive to assist in its digestibility and encourage the gut health.

Anchoring Catalytic Metal Nodes within a Single-Crystalline Pyrazolate Metal-Organic Framework for Efficient Heterogeneous Catalysis.

The synthesis of single-crystalline and robust pyrazolate metal-organic frameworks (Pz-MOFs) capable of facilitating challenging organic transformations is fundamentally significant in catalysis. Here we demonstrate a metal-node-based catalytic site anchoring strategy by synthesizing a single-crystalline and robust Pz-MOF (PCN-1004). PCN-1004 features one-dimensional (1D) copper-Pz chains interconnected by well-organized ligands, forming a porous three-dimensional (3D) network with two types of 1D open channels. Notably, PCN-1004 displays exceptional stability in aqueous solutions across a broad pH range (1 to 14), attributed to the robust copper-Pz coordination bonds. Significantly, PCN-1004 functions as an outstanding catalyst in cross dehydrogenative coupling reactions for constructing C-O/C-S bonds, even in the absence of directing groups, achieving yields of up to ~99%, with long cycle lives and high substrate compatibility. PCN-1004 outperforms all previously reported porphyrin-based homogeneous and heterogeneous catalysts. Control experiments and computations elucidate the pivotal catalytic role of the copper-Pz chains and reveal a free radical pathway for the reaction. This work not only demonstrates the successful implementation of a metal-node-based catalytic site anchoring strategy for the efficient catalysis of challenging organic transformations but also highlights the synergistic effect of a robust framework, 1D open channels, and active sites in enhancing catalytic efficiency within MOFs.

Assembly and Stability of Virus Like Particles from the Gag Capsid Domain from the Human Endogenous Retrovirus HML‐2

AbstractThe capsid domain of the Gag protein from the human endogenous retrovirus HML‐2 can form virus‐like particles (VLPs) in vitro. Such particles made from proteins from other organisms are used as nanocarriers. Repeated use of exogeneous VLPs may however lead to an immune response. Recombinantly produced and purified capsid domain from HML‐2 could, given its human origin, provide a nanocarrier system, which potentially could evade an immune response. It is however not known if capsids formed in vitro by the HML‐2 Gag capsid domain can be loaded with a molecular cargo and if such particles are stable. In this work, we investigated how the assembly efficiency change with conditions. We demonstrate that once formed the capsids are stable over a much broader range of pH than the range of pH that allows capsid formation, and that the capsids are stable for weeks. We furthermore show that HML‐2 capsids can encapsulate small molecules. Our results suggest that the HML‐2 capsids potentially may serve as stable nanocarriers protecting its cargo from the surrounding environment.

PH Affects the Spontaneous Formation of H2O2 at the Air-Water Interfaces.

Recent studies have shown that the air-water interface of aqueous microdroplets is a source of OH radicals and hydrogen peroxide in the atmosphere. Several parameters such as droplet size, salt, and organic content have been suggested to play key roles in the formation of these oxidants. In this study, we focus on the effect of acidity on the spontaneous interfacial hydrogen peroxide formation of salt-containing droplets. Na2SO4, NaCl, and NaBr bulk solutions, at the range of pH 4 to 9.5, were nebulized, using ultra high-purity N2/O2 (80%/20%), and H2O2 was measured in the collected droplets. All of the experiments were performed in T = 292 ± 1 K and humidity levels of 90 ± 2%. For Na2SO4 and NaCl, the H2O2 concentration was increased by ∼40% under alkaline conditions, suggesting that OH- enriched environments promote its production. When CO2 was added in the ultrapure air, H2O2 was observed to be lower at higher pH. This suggests that dissolved CO2 can initiate reactions with OH radicals and electrons, impacting the interfacial H2O2 production. H2O2 formation in NaBr droplets did not display any dependence on the pH or the bath gas, showing that secondary reactions occur at the interface in the presence of Br-, which acts as an efficient interfacial source of electrons.

Biological and genomic characterization of a polyvalent phage PSH-1 against multidrug-resistant Salmonella Enteritidis

BackgroundBacteriophage has been renewed attention as a new antibacterial agent due to the limitations of antibiotic treatment. Bacteriophages are generally thought to be highly host specific and even strain specific, but a small number of polyvalent bacteriophages have been found to infect bacteria of different genera.ResultsIn this study, a virulent lytic bacteriophage (named Salmonella phage PSH-1) of Salmonella Enteritidis was isolated from the sewage samples of a large-scale pig farm, PSH-1 demonstrated lytic activity against four multidrug-resistant Salmonella Enteritidis isolates and Escherichia coli, and then its biological characteristics, genome and bacteriostatic ability were investigated. The results showed that the initial titer of PSH-1 was 1.15 × 1010 PFU/mL and the optimal multiplicity of infection (MOI) was 0.01, PSH-1 has stable activity in the range of pH 3.0–11.0. One-step growth curve showed that its latent period was 20 min, burst time was 80 min, and the burst was 495 particles. The whole-genome sequencing results revealed phage PSH-1 had a linear dsDNA with 48,466 bp length. The G/C content was 45.33%. Non-coding RNA genes and virulence factors were not found. Eighty- five open reading frames (ORFs) were identified after online annotation. By tests, the use of phage could succeed in controlling the artificial Salmonella contamination in milk at a range of temperatures.ConclusionsThis study reports a novel Salmonella Enteritidis phage PSH-1, which has a robust lytic ability, no virulence factors, and good stability. The characterization and genomic analysis of PSH-1 will develop our understanding of phage biology and diversity and provide a potential arsenal for controlling of salmonellosis.

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.

Electrochemical sensor for the analysis of 5-hydroxymethylcytosine in the presence of cytosine using pencil graphite electrode

In recent years, important efforts have been made to elucidate the mechanisms of epigenetic regulation, and one of the most studied epigenetic modifications was DNA methylation/demethylation. In this study, the voltammetric behaviour of 5-hydroxymethylcytosine was studied in the pH range of 2.00 – 11.00 using pencil graphite electrodes by differential pulse and square wave voltammetry. The effect of buffer solutions, scan rate, square wave voltammetry parameters, and stripping conditions on the voltammetric responses of 5-hydroxymethylcytosine were performed. The electrochemical oxidation process of 5-hydroxymethylcytosine on the pencil graphite electrode was realized under adsorption control. In human urine, by square wave stripping voltammetry, 5-hydroxymethylcytosine was quantified in a concentration range of 1.00 × 10-5 M-2.00 × 10-4 M. The proposed method was tested in the presence of cytosine in human urine. The recovery value of 5-hydroxymethylcytosine was found to be 99.57 %.

Characterization of a marine endolysin LysVPB against Vibrio parahaemolyticus

Currently, there is an urgent to develop safe and environmentally friendly alternatives to antibiotics for combating Vibrio parahaemolyticus. Endolysins are considered promising antibacterial agents due to their desirable range of action and ability to deal with antibiotic-resistant bacteria. While numerous Vibrio phages have been identified, the research on their endolysins is still in its infancy. In this study, a novel endolysin called LysVPB was cloned and expressed in Pichia pastoris. Phylogenetic analysis revealed that LysVPB bears little resemblance to other known endolysins, highlighting its unique nature. Homology modeling identified a putative calcium-binding site in LysVPB. The recombinant LysVPB achieved a lytic activity of 64.8 U/mL and had a molecular weight of approximately 17 kDa. LysVPB exhibited enhanced efficacy at pH 9.0, with 60 % of its maximum activity observed within the broad pH range of 6.0–10.0. The catalytic efficiency of LysVPB peaked at 30 °C but significantly declined beyond 50 °C. Ba2+, Co2+, and Cu2+ showed inhibitory effects on the activity of LysVPB, while Ca2+ can boost it to 126.8 %. Furthermore, LysVPB exhibited satisfactory efficacy against strains of V. parahaemolyticus. LysVPB is an innovative phage lysin with good characteristics that are specific to certain hosts. The modular nature of LysVPB allows for efficient domain exchange with alternative lysins as antimicrobial components and fusion with antimicrobial peptides. This opens up possibilities for engineering chimeric lysins in a broader range of target hosts with high antimicrobial effectiveness and strong activity under physiological conditions.

Decontamination of Organophosphates: Efficacy of Oxime Incorporated Palm Oil based Liquid Soaps for Methyl Parathion Neutralization

Organophosphates (OPs) are a group of poisonous chemicals that are commonly used as pesticides and at times as chemical weapons. Decontamination of these compounds from the contaminated surfaces is an important step in their poisoning incident management but techniques that are commonly used currently, washings with soap solutions are not effective as the contaminants are still active in the waste solutions. Addition of an active ingredient such as an oxime which acts as a nucleophile in the soap solutions will enhance the ability of the washing liquids to hydrolyse OPs to convert them into innocuous compounds. This article describes a procedure to synthesize and characterize oxime-incorporated palm oil-based liquid soaps with an oxime concentration in the range of 0.05–1% and the results of their evaluation for their decontamination efficacy to degrade the OPs into non-toxic compounds. The soaps were formulated from palm oil and stable with the pH of 11.0, which is within the pH range for decontamination purposes. Upon mixing the soap solutions with Methyl Parathion (MP), the MP degrades slowly with the formation of p-nitrophenol (p-NP) after 24h which appears at peaks 400nm of the UV-Visible spectrum. However, in the presence of 2-pyridine aldoxime methiodide (2-PAM) with concentrations of 0.05% to 1.0%, the degradation is immediately observed involving the 2-PAM/MP complexation, in addition to the formation of p-NP after 24h. Furthermore, with the concentration of 2-PAM of 0.5% to 1.0%, the degradation does not produce p-NP but dimethylthiophosphate (DMPT) suggesting that the oxime content in the soap is sufficient to neutralise the MP. Based on the above findings, it can be concluded that the addition of the 2-PAM at the right concentration into the soaps significantly enhances their ability to efficiently decontaminate MP.

Highly selective removal of thallous ions from wastewater using Prussian Blue biochar composite

Thallium, a highly toxic pollutant, shows greater toxicity to human than other common heavy metals such as mercury, lead, cadmium and its effective removal from wastewater gains great attention. The main restriction for the Tl+ removal is the interference of a high concentration of co-existing ions in wastewater. Therefore, the goal of the current work was to synthesis adsorbent with high selectivity for the Tl+ removal. Herein, the pore size sieving strategy was proposed and Prussian blue-impregnated biochar (BC@PB) particles was synthesized. More than 95% Tl+ can be removed even the concentrations of the coexistence ions (Na+, Cd2+, and Zn2+) 1,000 higher than the initial concentration of Tl+ (500 μg/L). BC@PB also showed large adsorption capacity (9365 μg/g) and more than 99% Tl+ (initial concentration, 500 μg/L) were removed in just 1 min. The BC@PB had excellent and stable Tl+ removal ability (> 99%) over a range of pH from 3 to 9, which covered the pH range of common thallium-containing wastewater. The density functional theory (DFT) calculation confirmed that not only hydrated volume but also the hydration free energy of ions, which governed the energy barrier for ions entering into narrow channels of BC@PB, played essential roles on the selectivity removal of Tl+. Overall, due to its high selectivity, high adsorption capacity and easy preparation process, the synthesized BC@PB particles based on the pore sizing sieving strategy, can be a promising candidate for the removal of thallium from wastewater.

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.

Low-tech innovation: biomimetic solid-contact potentiometric sensor for nanomolar-level atrazine detection.

Despite the fact that there are already a number of solid-contact-based ion-selective electrodes designed for atrazine detection, our ground-breaking contribution lies in introducing the first-ever atrazine potentioselectrode, enabling the ultra-sensitive detection of atrazine at nanomolar levels. Solid-contact ion-selective electrodes can offer advantages, such as improved stability, reproducibility, sensitivity, and selectivity compared to their liquid-contact counterparts. Here, a biomimetic potentiometric sensor for Atrazine was developed using economic, light weight, and flexible carbon cloth as solid-contact material. Our methodology entails the synthesis of a molecularly imprinted polymer (MIP) through straightforward precipitation polymerization, showcasing a streamlined and efficient method for creating highly specific molecular recognition elements. The validation of template removal is confirmed via meticulous analysis employing EDX and FTIR techniques, ensuring the efficacy of our methodology. The resulting sensing membrane are casted by dispersing the MIP in 2-nitrophenyl octyl ether plasticizer and embedding it within a PVC matrix containing sodium tetraphenyl borate as a lipophilic additive. The developed sensor responds to atrazine in the pH range of 2.8-3.3 over a wide concentration range of 1 × 10-8M to 1 × 10-5M & 1 × 10-5M to 1 × 10-1M with respective slopes of 29.2 mv & 58.7mV and a limit of detection of 1 × 10-9M. An impressive feature of this sensor lies in its swift response time, registering a rapid reaction within a mere 10s. Emphasize the sensor's commendable attributes of reproducibility, selectivity, and sensitivity underscoring its successful application in field monitoring.

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.

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.

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.

Electrical and fluorescence in situ monitoring of tumor microenvironment-based pH-responsive polymer dot coated surface

A boronate-ester structure forming a pH-responsive polymer dot (Plu-PD) coated biosensor between carbonized-sp2 rich dopamine-alginate [PD(Alg)] and boronic acid-grafted Pluronic (BA-Pluronic) was developed for the electrochemical and fluorescence detection of cancer cells. The reduced fluorescence (FL) resulting from fluorescence resonance energy transfer (FRET) mediated by π-π interactions within Plu-PD was successfully reinvigorated through the specific cleavage of the boronate-ester bond, triggered by the acidic conditions prevailing in the cancer microenvironment. The anomalous variations in extracellular pH levels observed in cancer (pH ∼6.8), as opposed to the normal cellular pH range of approximately 7.4, serve as robust indicators for discerning cancer cells from their healthy counterparts. Moreover, the Plu-PD coated surface demonstrated remarkable adaptability in modulating its surface structure, concurrently exhibiting tunable electroconductivity under reduced pH conditions, thereby imparting selective responsiveness to cancer cells. The pH-modulated conductivity change was validated by a reduction in resistance from 211 ± 9.7 kΩ at pH 7.4 to 73.9 ± 9.4 kΩ and 61.5 ± 11.5 kΩ at pH 6.8 and 6.0, respectively. The controllable electrochemical characteristics were corroborated through in vitro treatment of cancer cells (HeLa, B16F10, and SNU-C2A) via LED experiments and wireless output analysis. In contrast, identical treatments yielded a limited response in normal cell line (CHO–K1). Notably, the Plu-PD coated surface can be seamlessly integrated with a wireless system to facilitate real-time monitoring of the sensing performance in the presence of cancer and normal cells, enabling rapid and accurate cancer diagnosis using a smartphone.

Strong and pH dependent fluorescence in unprecedented anthra[2,3-d]imidazole derivatives

We here report the synthesis and characterization of three new molecules based on an unprecedented anthra [2,3-d]imidazole unit. The new heterocycle was unexpectedly formed while attempting to obtain 2,3-diacetamidoanthracene by reducing the corresponding anthraquinone molecules by sodium borohydride. The same reaction was successfully performed using two further different 2,3-diamidoanthraquinone derivatives, thus confirming its generality. The chemical identity of the novel molecules was also proved by realizing single crystals suitable for XRD diffraction and solving the crystalline structure of one of the prepared systems. All the molecules are strong blue emitters in ethanol, with fluorescence quantum yields around 0.40. Because of the acid-base properties of anthraimidazole ring, the optical response was investigated at different pH values. While slight differences were observed in acidic conditions, in the alkaline pH range we observed a dramatic change of the fluorescence spectra in a narrow pH range (from 11 to 13), with the color of the emission turning from blue to green. This feature makes the new class of derivatives here reported very promising as pH sensors working in strongly alkaline conditions.