Wide pH Range Research Articles

Stratified nanoflower bimetallic cobalt/iron alloy derived from CoFe-MOFs as efficient peroxymonosulfate activator for antibiotics degradation: Performance, mechanism, and toxicity

Co-based metal-organic framework (Co-MOFs) derivative has gained wide attention in the field of advanced oxidative processes (AOPs). However, the degradation efficiency of single cobalt element remains suboptimal and its activation mechanism still needs to be further explored. In this study, stratified nanoflower bimetallic cobalt/iron alloys (CoFe-NC), derived from cobalt/iron bimetallic-organic frameworks (CoFe-MOFs), was synthesized via self-assembly at room temperature, hydrothermal synthesis and high-temperature carbonization processes and their performance as efficient activators of peroxymonosulfate (PMS) for the degradation of antibiotics was evaluated (removal efficiency of 100 % within 40 min, k=0.0951 min−1). The excellent degradation property benefit by specific nano-flowers structure with high specific surface area (424.67 m2/g), the cycle between Co0→Co2+↔ Co3+ and Fe0→Fe2+↔Fe3+, synergistic effect of Co and Fe bimetals. Furthermore, the CoFe-NC/PMS system exhibits exceptionally high cyclic stability (over 85 % degradation efficiency after four times degradation), a wide range of pH (3−11) and resistance to background ion interference (Cl–, H2PO4–, NO3–, HCO3– and HA), and reduced toxicity of the degradation products. Degradation mechanistic studies demonstrated that the activation of PMS by CoFe-NC generated amounts of reactive oxygen species (ROS) (SO4•−, •OH, •O2− and 1O2). Additionally, high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis identified fifteen intermediate degradation products and three possible degradation pathways were proposed. The results highlight the potential of CoFe-NC as a catalyst for antibiotic removal, providing insights into the optimization of bimetallic-organic framework for environmental applications.

A single-atom manganese nanozyme mediated membrane reactor for water decontamination

Single-atom nanozymes possess high catalytic activity and selectivity, and are emerging as advanced heterogeneous catalysts for environmental applications. Herein, we present the innovative synthesis and characterization of a single-atom manganese-doped carbon nitride (SA-Mn-CN) nanozyme, integrated into a polyvinylidene fluoride (PVDF) membrane for advanced water treatment applications. The SA-Mn-CN nanozyme demonstrates high peroxidase-like activity, efficiently catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) and generating reactive oxygen species (ROS) for effective antibacterial action. Notably, the SA-Mn-CN/PVDF membrane showcases enhanced water permeability, superior antifouling properties, and ultra-fast degradation kinetics of organic pollutants. Mechanistic studies reveal that the nanozyme selectively generates Mn(IV)-oxo species via peroxymonosulfate (PMS) activation, crucial for the efficient oxidation processes. Our integrated membrane system effectively removes (within 1 min, > 92 % removal) a variety of organic micropollutants in continuous-flow operations, demonstrating excellent stability and minimal manganese leaching. Compared to conventional advanced oxidation process (AOPs)/membrane system, the SA-Mn-CN/PVDF/PMS system holds the advantages of high catalytic activity and selectivity for generation of reactive species, wide working pH range (pH3–11) and excellent stability and reusability under the backwashing conditions. The developed device-scale AOPs/membrane system was proven to be effective in bacterial inactivation and pollutants degradation, verifying the vast application potential of the SA-Mn-CN/PVDF membrane for practical water decontamination. This work pioneers the development of enzyme-mimicking nanozyme membranes, offering a sustainable and high-performance solution for wastewater treatment, and sets a new benchmark for the design of nanozyme-based catalytic membranes in environmental applications.

Isolation, characterization, and application of a novel Pseudomonas fluorescens phage vB_PF_Y1-MI in contaminated milk.

The food industry has incurred substantial losses from contamination by Pseudomonas fluorescens, emphasizing the critical importance of implementing effective control strategies. Phages are potential sterilizers due to their specific killing abilities and the difficulty bacteria face in developing resistance. However, a significant barrier to their development is the lack of diversity among phage types. In this study, we characterized a novel lytic P. fluorescens phage, named vB_PF_Y1-MI. Phage vB_PF_Y1-MI displayed a latent period of nearly 10min and a high burst size of 1493 PFU/cell. This phage showed good activity over a wide range of temperature (up to 70°C) and pH (3-12). The genome of phage vB_PF_Y1-MI spans 93,233bp with a GC content of 45%. It encompasses 174 open-reading frames and 19 tRNA genes, while no lysogeny or virulence-associated genes were detected. Phylogenetic analysis positions it as a novel unassigned evolutionary lineage within the Caudoviricetes class among related dsDNA phages. Our study provides foundational insights into vB_PF_Y1-MI and emphasizes its potential as an effective biological control agent against P. fluorescens. This research offers crucial theoretical groundwork and technical support for subsequent efforts in preventing and controlling P. fluorescens contamination.

Earth-Abundant CuWO4 as a Versatile Platform for Photoelectrochemical Valorization of Soluble Biomass Under Benign Conditions.

Here, a nanosheet-structured CuWO4 (nanoCuWO4) is demonstrated as a selective and stable photoanode for biomass valorization in neutral and near-neutral solutions. nanoCuWO4 can be readily prepared by a solid phase reaction using nanosheet-structured WO3 as the template. Several substrates, including glucose, fructose and glycerol, are investigated to reveal the wide applicability of nanoCuWO4. The activity and product distribution trends in biomass valorization are investigated at different pH by taking advantage of the promising stability of nanoCuWO4 in a wide pH range. Product analyses confirm that formate production with a Faradaic efficiency (FE) of 76 ± 5% and glycolate production with an FE of 61 ± 8% can be achieved by glucose and fructose valorization at pH 10.2, respectively. On the other hand, glyceraldehyde and dihydroxyacetone (DHA)are the main products in the glycerol valorization, accounting for an FE of over 85% at pH 7. Notably, nanoCuWO4 has the highest FE of DHA in photoelectrochemical (PEC)glycerol valorization compared to WO3 and BiVO4 at neutral pH. The oxidation routes and mechanism of glycerol valorization on nanoCuWO4 are also under investigation. The co-production of H2 and value-added chemicals is finally demonstrated using a photovoltaic cell connected to a nanoCuWO4-based PEC glycerol valorization system.

Co-based carbon material as CYP3A4-like nanozyme with both biocatalytic activity and inhibition behaviors

Up to now, the biocatalytic activity of nanozymes has been extensively studied, while little research focus on their inhibitory behaviors. Here, Co-based carbon material (Co-DMOF) containing abundant carboxylic acid groups was prepared, with defects introduced by COx escape during pyrolysis to achieve controllable activity. As a result, Co-DMOF exhibited biocatalytic activity similar to cytochrome P450 3A4 (CYP3A4) in the metabolism of 1,4-Dihydropyridine (1,4-DHP, a calcium channel blocker). Excitingly, studies on IC50 and drug-drug interaction (DDI) suggested that Co-DMOF had similar inhibitory behaviors to CYP3A4. Moreover, Co-DMOF displayed excellent stability even under high temperature (100 °C), organic solvents, and a wide range of pH (4–9). Additionally, it can be reused for at least 7 times with only slight loss of activity. Therefore, Co-DMOF has great potential to become a low-cost alternative to CYP3A4 for drug dosage guideline, drug metabolism and DDI. This work provides more possibilities for expanding the CYP3A4-like nanozyme library.

Computational screening of single-atom transition metals on boron-rich boron nitride nanosheets for efficient hydrogen evolution catalysis in all pH range.

Low-cost and high-efficiency catalysts are of crucial importance for the electrocatalytic hydrogen evolution reaction (HER). Two-dimensional (2D) boron nitride (B-N) compounds formed by the combination of boron and nitrogen atoms of group III and V elements are promising candidates for electrocatalytic HER due to their significant electronic properties. Hence, an electrocatalyst is computer-aided designed with isolated single atoms of 3d, 4d, and 5d transition metals supported on 2D B-N (B2N, B5N3, and B7N5) monolayers to fabricate single-atom catalysts (SACs) with an excellent HER performance. Moreover, pH modulations are considered to improve the HER activity theoretically based on first-principles calculation. Our results indicate that B-N compounds surface doping with transition metal atoms can effectively enhance the HER catalytic performance over a wide range of pH. Among all SACs studied, Co-, Ti-, V-, Nb-, Ru-, Tc-, Zr-, and Os-embedded B2N, Sc-, Cr-, Mn-, Ti-, and Y-embedded B5N3, and Sc- and Mn-embedded B7N5 have excellent catalytic activity under acidic conditions, while Mo-, Ir-, Re-, Ta-, and W-embedded B2N and Ti- and Fe-embedded B7N5 show high catalytic activity under alkaline conditions. Interestingly, Hf@B2N and V@B5N3 systems exhibit promising catalytic activity under acidic, neutral, and alkaline conditions. Our work offers cost-effective candidates with a wide pH range HER performance for exploring ideal electrocatalysts.

Microenvironment regulation for high-performance acidic CO2 electroreduction on Poly(ionic liquid)-modified Cu surface

Electrocatalytic reduction of CO2 (CO2RR) under acidic conditions provides a feasible way for converting CO2 to multi-carbon products (C2+) with high feedstock conversion and high energetic efficiency (EE). In this work, poly(ionic liquid) (PIL)-Cu hybrids were employed as excellent acidic CO2RR electrocatalysts. A high faradaic efficiency towards C2+ products (FEC2+) of more than 61.0 % was achieved within a wide pH range from 2 to 14 at –700 mA cm–2. The optimum FEC2+ of 83.1 % was obtained at –700 mA cm–2 and pH = 2, corresponding to an EEC2+ of 37.6 %. By reducing the inlet CO2 flow rate to 1.59 mL min–1, a very high CO2 single-pass conversion of 98.7 % was achieved at –300 mA cm–2. The confinement of PIL layer caused by the semi-rigid abundant porous structure and dense cationic-anionic network enables the maintenance of a moderate local alkaline microenvironment and enrichment of K+ cations at the active sites. These effects jointly promote the C–C coupling at the Cu-PIL interface under acidic conditions. Remarkably, the CO2RR pathway can be regulated by functionality and morphology of the PIL layer.

Influence of boric acid on the speciation of iron (III) in aqueous solutions

During the work, the speciation of iron (III) was studied at the concentration of ~ 1∙10–5 mol/dm3 in aqueous solutions in the presence of boric acid at a concentration of 5–20 g/dm3 in a wide pH range using ion exchange, ultrafiltration and centrifugation methods. The regions of existence of ionic and nonionic forms of iron (III) were determined by ion exchange in solutions with different boric acid concentrations. Experimental data have shown that the pH of the onset of iron (III) colloid formation shifts in the presence of boric acid. The formation of complex compounds of iron (III) with polyborate ions in the neutral – slightly alkaline pH region was established by ultrafiltration and centrifugation. As shown in the paper, the increase in the concentration of boric acid in solution leads to the increase in the region of existence of the supposed complexes. The identified features of the behavior of iron (III) in solutions containing boric acid determine the possibility of using ion exchange and membrane separation methods for purifying solutions. Information about the physical-chemical properties of various metal-ions can provide optimal conditions for the purification of liquid radioactive waste at various nuclear industry facilities.

Integrating Pt single atoms and Mo into PtNi/C through Mo doping-displacement synchronisation strategy for enhanced HER at all pH values

This paper proposes a Mo doping-displacement synchronization strategy to integrate Pt SAs and Mo atoms into PtNi/C, synthesizing Pt SAs/Mo-doped PtNi octahedra/carbon support catalyst (Pt SAs/Mo-PtNi/C). In this approach, Mo atoms are doped into PtNi alloy octahedra and displace some Pt atoms, forming Mo-PtNi octahedra. Importantly, the substituted Pt atoms can adhere to carbon substrate, creating Pt SAs. Pt SAs/Mo-PtNi/C exhibits lower overpotentials (38, 59, and 110 mV at 10 mA cm−2) and smaller Tafel slopes (44, 51, and 139 mV dec-1) in acidic, alkaline, and neutral environments. Additionally, the electron pathway of Mo-PtNi → Pt SAs/C has been confirmed, and Pt SAs/Mo-PtNi/C exhibits an optimized hydrogen adsorption energy (ΔGH*=-0.29 eV). Furthermore, catalyzed by Pt SAs/Mo-PtNi/C, the H-O bond length of H2O extends to 1.11 Å and the bond angle reduces to 102.741°, directly confirming that the Pt SAs and doped Mo could facilitate H-O bond breaking. The proposed Mo doping-displacement synchronization strategy not only simplifies the fabrication process of Pt SAs catalyst, but also improves its durability and activity across a wide pH range, thereby potentially advancing hydrogen production technologies.

Transforming tire-derived char into powerful arsenic adsorbents by mild modification

A large amount of arsenic-containing wastewater discharged by the non-ferrous metal industry will cause serious environmental problems if it is not properly treated. Pyrolysis char of waste tire is a kind of solid waste. Since the surface properties of tire derived char (TC) are affected by tar/ash adhesion during pyrolysis, it is necessary to modify TC to treat wastewater containing As(V) effectively as an adsorbent. At present, most studies on the modification of TC are prepared into activated carbon by high temperature activation in N2 atmosphere. In this study, TC was modified at room temperature and air atmosphere, and Fe(OH)3-TCNaOH adsorbent with particle size of 61–75 μm was obtained under the premise of the removal rate of As(V) and the settling performance of the adsorbent. When the initial concentration of As(V) was 5 mg/L, the removal rate of As(V) by Fe(OH)3-TCNaOH with a particle size of 61–75 μm could reach 90% within 30 min under a wide pH range (3–9). The adsorption of As(V) by Fe(OH)3-TCNaOH was most affected by the coexistence of PO43-, which resulted in the removal rate of As(V) decreased by about 20%. The adsorption mechanism shows that the significant increase in the number of 3–5 nm mesoporous pores of Fe(OH)3-TCNaOH and the formation of H bonds are beneficial to the adsorption of Fe(OH)3-TCNaOH to As(V), and improve the stability of Fe-As complex.

Smart paper-based materials incorporating nitrogen and boron co-doped MXene quantum dots for rapid adsorption and sensitive detection of Cr2O72−

Dichromate ion (Cr2O72−) is a highly toxic chromium-containing compound that poses significant hazards to the digestive, respiratory systems, skin, and mucous membranes. Currently, the detection and adsorption of Cr2O72− face significant challenges, including the time-consuming and low sensitivity nature of traditional analytical methods. The limited efficiency and capacity of existing adsorbents hinder their practical application in real-time water quality monitoring and environmental remediation. Herein, using polyethyleneimine-functionalized (PEI) pulp fiber paper as the substrate, we developed smart paper-based materials (designated as NB-MQDs@PP) incorporated with nitrogen and boron co-doped MXene quantum dots (NB-MQDs) for rapid adsorption and sensitive detection of Cr2O72−. Compared to undoped MQDs, NB-MQDs exhibited longer excitation wavelength and enhanced oxidation stability. As anticipated, NB-MQDs achieved rapid (response time of 10 s) and sensitive (detection limit of 1.2 μM) recognition of Cr2O72− within a wide pH range with a quenching efficiency of 99.9%. Simultaneously, two on-site detection methods, immersion and cyclic filtration, were constructed based on NB-MQDs@PP. The detection limit of the immersion method was 17.0 nM, while the cyclic filtration method had a detection limit as low as 3.8 nM, surpassing the majority of those reported literatures. Remarkably, NB-MQDs@PP exhibited outstanding enrichment capacity towards Cr2O72−, with an adsorption capacity of up to 162.4 mg/g. This work provides a novel strategy for creating unique paper-based materials with excellent capture and monitoring dual-function, which can be customized according to the requirements of various application scenarios.

Sensitive Detection and Visual Recognition of Jatrorrhizine Based on a Fluorescent Eu Coordination Polymer Probe

ABSTRACTBased on 4‐([2,2′:6′,2″‐terpyridin]‐4′‐yl) benzoic acid ligand (Htpba), a fluorescent lanthanide coordination polymer was successfully synthesized, namely, [Eu (tpba)3]n (1). The single‐crystal diffraction analysis shows that Eu3+ ions in complex 1 are alternately connected with tpba3− ligands to form a one‐dimensional chain structure, which further constitutes a three‐dimensional supramolecular architecture through the π···π interactions. Complex 1 demonstrated excellent stability of thermogravimetry; and displayed good fluorescence intensity in aqueous solution with a wide pH range. In this work, complex 1 was used as a fluorescence sensor for the detection of jatrorrhizine molecule (JAT). It was found that complex 1 had high sensitivity with the detection limit of 1.02 × 10−8 M, and simultaneously displayed specific selectivity and reutilization for the exploration of JAT molecule. The static quenching, the absorption competition, the electrostatic interactions, and the photo‐induced electron transfer process are responsible for the recognition mechanism of complex 1 with sensing JAT. It is worth mentioning that a fluorescent film based on complex 1 and a light‐emitting diode device coated with the powder of complex 1 were successfully fabricated, which could rapidly recognize JAT molecule with the naked eye further.

Excellent antibiotic degradation through PMS activation via bio derived Fe-Mn oxides with tunable defect concentration: Synergy between singlet oxygen oxidation and electron transfer

Regulating the defect sites and structural composition of metal-based metal catalysts is an effective strategy to improve the activity of activating PMS to degrade pollutants. Herein, bio derived Fe/Mn composite oxides (BFMO) rich in oxygen vacancy composed of crystalline manganese oxide coated with amorphous iron oxide was prepared through microbial mediation, and used for PMS activation in the degradation of tetracycline (TC). After 60 minutes reaction, the removal rate of TC achieved 92.4 %−98.8 % within wide pH range of 3–12. Besides, this system has outstanding anti-interference ability to common ions and humic acid (HA). The outstanding catalytic performance stemmed from the non-radical pathway for producing singlet oxygen (1O2) and electron transfer, facilitated by defect-rich polyvalent Mn and amorphous Fe species. Polyvalent Mn species accelerate the electron transfer process, and its surface defect structure further promotes the adsorption of pollutants on the surface of the materials. The redox cycle of Fe3+/Fe2+ was accelerate via electron-rich groups. This study explored the synergy triggered by microbe-mediated defect sites and structure-dependent, providing a design strategy for environmental remediation of PMS activated by Fe/Mn based bimetallic catalysts with strong resistance to environmental interference.

Ultrafine Fe-Mn bimetallic nanoparticles anchored in nitrogen-doped carbon nanofiber electro-Fenton membrane with strong metal-support interactions for sustainable water decontamination in wide pH ranges

Designing a membrane electrode with high activity and anti-scaling ability in a wide pH range is crucial to the development of flow-through electro-Fenton system. Herein, we reported a novel porous membrane composed of ultrafine FeMn bimetallic nanoparticles anchored in nitrogen-doped carbon nanofibers (FeMn/N-CNF) obtained through a facile electrospinning-carbonization process. The strong metal-support interaction (SMSI) phenomena including carbon encapsulation structure and electron transfer from metal to N-CNF, beneficial to the intrinsic activities, were successfully induced by the enhanced interfacial metal-nitrogen bonding in FeMn/N-CNF. Microstructural characterizations and leaching test revealed that the SMSI encapsulation structure could promote the formation of ultrafine FeMn nanoparticles in N-CNF during the high-temperature carbonization process and prevent leaching of active Fe/Mn metals into solution across a wide pH range. The constructed gravity-driven flow-through electro-Fenton system based on a FeMn/N-CNF cathode membrane exhibited superior performance to generate H2O2 (36.23 mmol L−1 h−1) and subsequent activate H2O2 decomposition to hydroxyl radicals (0.1024 min−1), achieving remarkable degradation efficiencies of 96.8%, 92.3%, and 90.3% within 60 min for Rhodamine B, Tetracycline, and Methyl Orange, respectively. Furthermore, the FeMn/N-CNF membrane filter demonstrated good pH adaptability, excellent cycle stability and anti-scaling ability during the degradation process. This work offers a viable avenue to enhance degradation performance and environmental robustness for practical water decontamination via achieving SMSI effect in carbon-supported electro-Fenton membranes.

Strong enhancement on diclofenac degradation in Cu(II)/H2O2 system by adding ascorbic acid: Efficiency, mechanism and influencing factors

Utilization of trace Cu(II) (at μM level) inherently existing in wastewater to activate hydrogen peroxide (H2O2) has exhibited significant potential to remove aqueous organic contaminants. Nevertheless, the Cu(II)/H2O2 system was only efficient under alkaline conditions. Herein, ascorbic acid (H2A), an environmentally benign and natural reductant, was introduced to broaden pH range of Cu(Ⅱ)/H2O2 process by expediting the Cu(II)/Cu(I) cycle. The H2A/Cu(Ⅱ)/H2O2 system performed well in degrading diclofenac across a wide pH range from 4.0 to 9.0, and its kinetic rate constant of diclofenac elimination was 247 times greater than its counterpart without H2A at the optimal pH of 6.0, outperforming the performance of most previously reported reductant-enhanced Cu(Ⅱ)/H2O2 system. Electron paramagnetic resonance analysis, periodate colorimetric method, and in situ Raman spectroscopy tests indicated that hydroxyl radical (HO), rather than Cu(III), was the dominant reactive species of diclofenac degradation. Thirteen degradation products of diclofenac were identified by LC-Q-TOF-MS, and five different elimination pathways were proposed. Furthermore, the presence of SO42− exerted an insignificant influence on diclofenac degradation, while the addition of Cl−, HCO3− and humic acid slightly suppressed the abatement of diclofenac. H2A/Cu(Ⅱ)/H2O2 system was still highly efficient in degrading diclofenac in actual water matrix (i.e., reservoir water and lake water). Overall, this study provided an eco-friendly approach to enhance the oxidation capacity of the Cu(II)/H2O2 system over a wide pH range, which might be a potential technology for degrading refractory organic pollutants in water treatment.

Novel Antarctic Endo-Polygalacturonase for Pectin Extraction and Vegetal Tissue Maceration at Mild Temperatures.

The aim of the present work was to partially purify and characterize an Antarctic polygalacturonase and to determine the enzyme's potential in pectin extraction and vegetal maceration at 20°C. Polygalacturonase was purified by chromatography to obtain an enzymatic preparation of specific activity 30.3 U.mg-1. Optimal conditions for the polygalacturonase activity were 45°C and pH 5.0-6.0, and the activation energy for the reaction was 41.8kJ.mol-1. Of the enzyme activity, 100% was retained after 3h at 40°C. The enzyme was remarkably stable for an hour over a wide range of pH (2.0-12.0). Polygalacturonase activity was slightly reduced in the presence of Ca+2, Fe+3, K+, Mn+2, and Zn+2, whereas Hg+2 reduced the activity by 60%, suggesting a thiol-dependent catalysis. The apparent molecular weight of the enzyme was 33kDa. The kinetic constants evaluated against polygalacturonic acid were 0.17mg.ml-1 (Km), 480s-1 (Kcat), and 7.9µmol.mg-1.min-1 (Vmax). The enzyme was active against different pectic substrates. Thin-layer chromatography revealed an endo-mechanism of action. Polygalacturonase digested lime pomace to aid the extraction of high-methoxylated pectin at 20°C and increased the vegetal maceration of Capsicum annuum by 24% over the control values.

Laccase mimetics as sensing elements for amperometric assay of 5-hydroxyindoleacetic acid in urine

Monitoring of the levels of 5-hydroxyindole-3-acetic acid (5-HIAA) is of significant importance for diagnostics of carcinoid tumors. We propose simple catalytic electrochemical sensors for the determination of 5-HIAA in urine using laccase and its mimetics. Laccase-like nanozymes (LacNZs) were synthesized via a chemical reduction, and resulting PtMn and MnO2 nanoflowers (NFs) demonstrated laccase-like activity similar to the laccase from the Trametes zonata. In addition, these LacNZs showed enhanced stability under a wide range of pH (3.0–7.5), temperatures (4–70 °C), and ionic strengths (up to 500 mM NaCl). The developed PtMn NF/graphite electrode, similar to a laccase/graphite electrode, can detect 5-HIAA with a high sensitivity (25 000 ± 12 A·M−1·m−2 and 1900 ± 9 A·M−1·m−2, respectively) and have linear ranges of 0.3 – 15 μM and 2 – 50 μM. The sensors work at low working potentials with a detection limit of 0.16 and 1.4 μM, covering the normal and pathologic ranges of 5-HIAA (1–50 μM) content in urine. They have been successfully applied to 5-HIAA assay in urine samples of people with various diseases and revealed good recovery values and reproducibility. Additionally, the LacNZ-sensor has the best stability and can be used up to 20 days.

Radical to non-radical conversion during PMS activation triggered by optimized electronic structure: Orientational regulation of oxidation pathway for water remediation

The orientational regulation of non-radical pathways is significant in the peroxymonosulfate (PMS)-based AOP for practical potential, but remains challenge. Here, the Se-doped Co(OH)2 hollow spheres (CoHS-Se-CR) were designed for PMS activation to rapidly degrade gatifloxacin (GAT) antibiotic, with over 95 % GAT removal in 20 min. DFT and experimental trials reveal the downshift of d-band center of Co 3d and O − H bond stretch in PMS via Se doping of Co(OH)2. The active HSO5•− generated via the breaking of O–H bond triggers the radical to the non-radical conversion of the degradation mechanism, dominated by 1O2 and assisted by electron transport process. Both oxygen vacancy and Se(Ⅵ) were involved in 1O2 generation and Co(III)/Co(II) cycle. The CoHS-Se-CR/PMS system showed high efficiency for GAT removal in a wide pH range and strong resistance to anionic interference. This work provides a new strategy for designing PMS activators to construct orientational non-radical AOP.

Development of red fluorescent probe for visual detection of N2H4 via nanofiber membrane and its application in environmental analysis and biological imaging

Hydrazine (N2H4) is widely used in most industrial production. It is a harmful environmental pollutant and has strong toxicity to living organisms. Hence, it is imperative to employ approach for the real-time monitoring and tracking of N2H4. In this study, we developed the fluorescent probe DYY, incorporating an acetyl group as the recognition moiety, to achieve efficient detection of N2H4. The findings revealed that DYY exhibits excellent sensitivity (with a detection limit of 81 nM) and a wide pH range (2−8) in the detection of N2H4. Notably, upon the addition of N2H4, the color of the DYY solution transitioned from purple to blue, accompanied the fluorescence intensity increased by 11-fold increase in 643 nm. In addition, DYY demonstrated its capability in detecting N2H4 contamination within environmental water samples. Significantly, polymer nanofibers embedded with DYY were fabricated through the process of electrospinning, allowing for the visual identification of N2H4. Furthermore, it showed excellent performance in detecting N2H4 in HepG2 cells and zebrafish, demonstrating its potential for labeling N2H4 in living systems. Therefore, we are confident that this probe holds significant potential for environmental analysis and the detection of health indicators in living organisms.

Mesoporous TiO2@nitrogen-doped carbon nanosheets implanted in flexible and robust chitosan membrane with dual-function for efficient adsorption of iodide and methyl orange from aqueous solution

Radioactive iodide (I−) and methyl orange (MO) are two leading pollutants in wastewater, posing significant health risks. Crosslinked chitosan membranes (CCM) combined with TiO2@nitrogen-doped carbon nanosheets (CCM/TiO2@NC) were prepared as efficient I− and MO adsorbents in wastewater. These membranes leverage multiple interactions between I−/MO and functional groups (−NH2, nitrogen-doped carbon, and TiO2) within the membrane. As expected, CCM/TiO2@NC exhibited high I− removal efficiencies of nearly 82 % across a wide pH range (pH 3 − 11) and an exceptional MO removal efficiency of 96.1 % at a neutral condition. The adsorption behaviors followed the Langmuir isotherm and pseudo-second order kinetic model for both species, achieving maximum adsorption capacities of 1.383 mmol/g (175.6 mg/g) for I− and 661.4 mg/g for MO, respectively. Additionally, CCM/TiO2@NC maintained a high absorption efficiency for both I− and MO through five regeneration cycles. The I− adsorption mechanism of CCM/TiO2@NC involves electrostatic attraction, anion-π interaction, and hydrogen bonding, while MO adsorption involves electrostatic attraction, n/π-π interactions, and hydrogen bonding. This study offers feasible guidance on developing chitosan/nanomaterial composites as promising adsorbents for removing I− and MO from wastewater.