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In this work, the novel ternary AgBr/Ag/PbBiO2Br Z-scheme photocatalysts were synthesized via a CTAB-assisted calcination process. The AgBr/Ag/PbBiO2Br composites were employed for ...the degradation of rhodamine B (RhB) and antibiotic bisphenol A (BPA) under visible light irradiation. Results showed that the obtained AgBr/Ag-3/PbBiO2Br displayed optimal photocatalytic performance, which could remove almost all RhB within 25 min and effectively decompose 82.3% of BPA in 120 min. Three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs) were utilized for the purposes of fully grasping the behaviors of RhB molecules during the reaction process. Meanwhile, the effects of initial RhB concentration and co-existent electrolytes were investigated from the viewpoint of practical application. In addition, there was no obvious loss in degradation efficiency even after four cycles. The enhanced photocatalytic performances of AgBr/Ag/PbBiO2Br could be credited to the accelerated interfacial charge transfer process and the improved separation of the photogenerated electron-hole pairs. The existence of a small amount of metallic Ag played a significant role in preventing AgBr from being further photocorroded, resulting in the formation of a stable Z-scheme photocatalyst system. This study demonstrated that using metallic Ag as an electron mediator to construct Z-scheme photocatalytic system provided a feasible strategy in promoting the stability of Ag-based semiconductors.
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•Isatis root extract was blended into PVP electrospun fibers to be antibacterial.•A portable electrospinning device was explored to achieve in situ application.•PVP/Isatis root ...electrospun wound dressing was directly deposited onto wound site.•In situ electrospun PVP/isatis root wound dressing promoted wound healing process.
Antibacterial dressings are an increasingly important tool for the prevention and management of wound infections, particularly in light of concerns surrounding conventional drug-resistant antibiotics. Handheld electrospinning devices provide opportunities for the rapid application of antibacterial dressing materials to wounds, but spinning formulations need to be compatible with live biological surfaces. We report the development of a new antibacterial formulation compatible with handheld electrospinning, and its manufacture directly on a wound site. Nanofibrous dressing mats were produced from polyvinyl pyrrolidone (PVP) containing isatis root (Indigowoad root or Ban-Lan-Gen), a traditional Chinese medicine, commonly used for the treatment of infectious disease. The resulting wound dressing mats of PVP/isatis root exhibited well-defined fibrous structures and excellent surface wetting, and permeability characteristics. The presence of isatis root conferred antibacterial activity against gram negative and gram positive strains. Moreover, in a Kunming mouse skin injury model, direct electrospinning of PVP/isatis root formulations on to wound sites produced near complete wound closure after 11 days and epidermal repair in histological studies.
•A fluorescent ratiometric sensor for water content determination in organic solvents was presented in this paper.•The fluorescence ratio sensor proposed in the paper minimized the influence of ...measuring external conditions and obtains a more stable signal.•The sensor showed satisfactory selectivity, reproducibility, stability, and fast response time.
This paper describes a fluorescent ratiometric sensor for water content determination in organic solvents. Two different compounds, 4′-N, N-dimethylamino-4-methylacryloylamino chalcone (DMC) and 5, 10, 15, 20-tetra-(4-methylacryloylaminophenyl)porphyrin Zinc (TMAPPZn), were synthesized as indicators for fluorescence ratiometric water sensing. DMC is a fluorescence indicator with charge donor parts and acceptor parts and sensitive to solvent polarity and water content. The fluorescence intensity of TMAPPZn is insensitive to the water content lower than 10% (v/v) water content and employed as the reference indicator. The use of TMAPPZn as a reference indicator resulted in a more stable signal due to minimizing the effects of fluctuations of light intensity, fluorophore bleaching, background signal, and so forth. DMC and TMAPPZn were photo-copolymerized on the silanized glass surface to prevent leakage of the fluorescence indicators. Three organic solutions (ethanol, acetone, and tetrahydrofuran) were used to verify the performances of the proposed sensor, and the sensor exhibited a good linearity in the range 0–10% (v/v) water content with detection limits of 0.0097%, 0.011%, and 0.017% for ethanol, acetone, and tetrahydrofuran, respectively. The ratiometric sensor was characteristic of satisfactory reproducibility, reversibility, short response time. The sensing membrane was found to have a lifetime of two month. We carried out preliminary spiking experiments on the actual samples, and the spiked recoveries were of 99.2–102.0%.
•A high BDE-47 debromination strategy assisted with solar energy is provided.•The artificial Z-scheme system possesses both reduction and oxidation abilities.•The novel system possesses enhanced ...charge carrier separation and transfer.•A possible transfer pathway of BDE-47 debromination was proposed.
2,2′,4,4′-Tetrabrominateddiphenyl ether (BDE-47), as one of polybrominated diphenyl ethers (PBDEs), has been proven to be global contaminant owing to widespread utilization as flame retardant. Herein, a novel visible-light-driven (VLD) artificial indirect Z-scheme system of Ag@Ag3PO4/g-C3N4/rGO is finely designed for BDE-47 removal assisted with abundant solar energy. The novel hybrid composite exhibits an enhanced reductive debromination activity with removal efficiency of 93.4% under visible light irradiation (λ > 420 nm) for 120 min, which is 173.65 times higher than pristine g-C3N4 catalyst. A series of experiments in terms of the environmental effects of initial concentration, pH, solvent and light source are performed to optimize the photocatalytic performance. The presence of rGO as an excellent storing and shuttling medium, can further facilitate the charge carrier separation in the indirect Z-scheme system for the enhanced photo-reduction debromination performance. The accumulated electrons on the solid catalyst can attack the ortho-Br of BDE-47 to formation of BDE-28, and then so on. The protons (H+) can be reduced to atomic hydrogen (H°), which can greatly weaken para-Br of BDE-47 to generation of BDE-17. Furthermore, the remaining holes can react with CH3OH to generate CH2OH radical, and then further directly produce electron for debromination process. A possible debromination pathway for BDE-47 was proposed. This work provides a green and promising strategy utilizing solar energy to remove BDE-47 in the liquid medium by virtue of VLD composite.
Radical‐containing frameworks (RCFs) have emerged as promising functional materials in various fields due to the combination of the highly ordered frame structure and the fascinating property of ...organic radicals. Here, the first example of radical‐containing supramolecular organic frameworks (SOFs) fabricated by the chaotropic effect between closo‐dodecaborate cluster (B12H122−) and 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine (TPT3+) is presented. The SOFs can be easily synthesized by stirring the B12H122− and the TPT3+ in aqueous solution through self‐assembly. Upon 435 nm light irradiation, the SOFs exhibits photochromic behavior from slight yellow (SOF‐1) to dark purple (SOF‐2). Electron paramagnetic resonance spectroscopy also reveals that stable radicals are generated in situ after light irradiation. Powder X‐ray diffraction demonstrates the SOFs maintain their structural stabilities upon light irradiation. More interestingly, the radical‐containing SOFs exhibit efficient photothermal effect under 660 nm light irradiation, which can be applied as photothermal agent for antibacterial application both in vitro and in vivo. This work highlights the construction of RCFs through supramolecular self‐assembly, which may arouse applications in energy, catalysis, photoluminescence, and biomedical fields.
Radical‐containing supramolecular organic frameworks (SOFs) can be easily synthesized by the chaotropic effect of closo‐dodecaborate cluster and 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine. The SOFs exhibit photochromic behavior under 435 nm light irradiation, while showing photothermal effect under 660 nm light irradiation. The radical‐containing SOFs can be applied as effective photothermal antibacterial agent in vitro and in vivo.
Schematic diagram for the antibacterial in the direct Z-scheme silver iodide decorated bismuth vanadate photocatalyst.
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Novel Z-scheme AgI/BiVO4 photocatalysts were fabricated by a ...chemical deposition-precipitation approach. The photocatalytic activities of the obtained catalysts were evaluated by disinfection of Escherichia coli (E. coli) and degradation of oxytetracycline hydrochloride (OTC-HCl) under visible-light irradiation. The BA3 (contained 9.09% of AgI) exhibited the highest photocatalytic activity and maintained good stability. It could completely inactivate 7.0×107 CFU/mL of E. coli in 50 min and degrade 80% of OTC-HCl in 60 min. The enhanced photocatalytic activity of AgI/BiVO4 composites could be ascribed to the lower recombination rate of electron-hole pairs. Meanwhile, radical trapping experiments revealed that the superoxide radical (O2−) and holes (h+) were the dominant reactive species in photo-disinfection process. Furthermore, the effects of bacterial initial concentration and inorganic anions were also investigated to optimize the photocatalyst for practical application. This study will give a new insight to construct the effective Z-scheme system for bacterial inactivation and organic pollutants degradation.
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At present, various organic pollutants and pathogenic microorganisms presented in wastewater have severely threatened aquatic ecosystem and human health. Meanwhile, semiconductor ...photocatalysis technology for water purification has attracted increasingly significant attention. Herein, we successfully constructed a series of novel visible-light-driven (VLD) Bi4O5I2/AgI hybrid photocatalysts with different AgI amounts. Compared with pristine AgI and Bi4O5I2, Bi4O5I2/AgI with the optimal AgI contents exhibited remarkably enhanced photocatalytic performance in probe experiment for Escherichia coli (E. coli) disinfection and tetracycline (TC) degradation. The efficiency for TC degradation and E. coli inactivation reached 82% and 100% in 30 min, respectively. The enhanced electron-hole separation efficiency was responsible for improved photocatalytic activity. In addition, the destruction process of the chemical structure of TC molecules was further investigated by three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs). The activity and crystal phase of the catalysts did not change significantly after four cycles, demonstrating their excellent recyclability and stability of catalysts. The Ag+ ion leaking experiments, radical trapping experiments and ESR tests demonstrated that OH, O2− and h+ were the main active species in photocatalytic disinfection processes. Furthermore, the photocatalytic mechanism of Bi4O5I2/AgI nanomaterials was discussed in detail in conjunction with the energy band structure, and a reasonable Z-scheme interfacial charge transfer mechanism was proposed. This work is expected to provide an efficient water disinfection method.
•Associations between cadmium exposure and cellular immune responses were examined.•Prenatal cadmium exposure was associated with reduced T lymphocyte subsets and increased Th2 cytokines.•The effects ...of prenatal cadmium exposure on cellular immune responses primarily occurred in females.•No clear associations between children’s concurrent cadmium exposure and cellular immune responses were observed.
Experimental studies have demonstrated that cadmium exposure induces alterations on immune function, but epidemiological evidence is lacking.
To examine the associations between prenatal and postnatal cadmium exposure and cellular immune responses among pre-school children.
Pre-school aged children (n = 407) were followed from a prospective birth cohort study in Wuhan, China. Maternal urinary and children’s plasma cadmium concentrations were measured as biomarkers of prenatal and postnatal cadmium exposure, respectively. Children’s cellular immune responses were assessed by peripheral blood T lymphocyte subsets and plasma cytokines. Multivariable adjusted models were applied to estimate the associations of prenatal and postnatal cadmium exposure with T lymphocyte subsets and cytokines, and the effect modification by child gender were also examined.
Maternal urinary cadmium was associated with reduced absolute counts of CD3+CD4+ cells (−12.45%; 95% CI: −23.74%, 0.40% for the highest vs. lowest quartile; p for trend = 0.045). Inverse associations of maternal urinary cadmium with %CD3+CD4+ cells and CD4+/CD8+ ratio were only observed among females (both p-interaction < 0.050); whereas an inverse association with absolute counts of CD3+CD8+ cells was only observed among males (p-interaction = 0.057). Positive associations of maternal urinary cadmium with %CD3+CD4+ cells, interleukin-4 (IL-4), and IL-6 were only observed among females, although there were no significant interactions. We observed no clear associations of children’s plasma cadmium with T lymphocyte subsets and cytokines.
Prenatal but not postnatal cadmium exposure was associated with sex-specific alterations on children’s cellular immune responses.
Compared to phase-change fibers with hydrophilic polymer shell, those with hydrophobic polymer are more stable in water and moist environments. However, their fabrication processes are involved in ...some toxic organic solvents. Here, the nanofibers with phase-change material (PCM, i.e., octadecane) as core and hydrophobic shell (i.e., polyvinyl butyral) are fabricated via coaxial electrospinning using environmental friendly ethanol as solvent. Effects of the polyvinyl butyral concentration in ethanol solution as well as the flow rates of core and shell fluids on the morphology of octadecane/polyvinyl butyral (PCM/PVB) nanofibers are systematically investigated. The thermo-regulating capability of PCM/PVB nanofibers is demonstrated by observing the surface and inner temperatures of model houses covered with fibers. The higher the PVB concentration and the shell flow rate are, the better the morphology of core/shell PCM/PVB nanofibers becomes, leading to higher encapsulation efficiency. At a constant shell flow rate, the encapsulation ratio of PCM/PVB nanofibers increases with the core flow rate. The encapsulation ratio of the PCM/PVB nanofibers, which fabricated with PVB concentration of 20 % (w/v) and at the core flow rate of 0.60 ml h⁻¹ and the shell flow rate of 3.0 ml h⁻¹, respectively, reaches to the maximum of 46.4 %. The corresponding melting enthalpy (ΔH ₘ) and the crystallization enthalpy (ΔH c) of these PCM/PVB nanofibers are 105.9 and 106.5 J g⁻¹, respectively. The PCM/PVB nanofibers exhibit good thermo-regulating capability under the simulated solar irradiation, regulating the temperature at around 28 °C. The resultant PCM/PVB nanofibers exhibit satisfactory stability and repeatability in the thermo-regulating capability during repeated heating/cooling cycles. The results provide valuable guidance for environmental friendly preparation of phase-change nanofibers with satisfactory and stable thermal characteristics.
Magnetic materials usually exhibit advanced performance in many areas for their easy separating and recycle ability. In this study, silver iodide/copper ferrite (AgI/CuFe
O
) catalysts with excellent ...magnetic property were successfully synthesized and characterized by a series of techniques. Two typical bacteria Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were applied to estimate the photocatalytic inactivation performance of obtained AgI/CuFe
O
catalysts. Results revealed that the AgI/CuFe
O
(12.5% AgI) composite could absolutely inactivate 3 × 10
CFU/mL E. coli and 2.7 × 10
CFU/mL S. aureus cells severally in 50 min and 40 min under visible light irradiation, which showed a much higher photo-disinfection activity than monomers. Transmission electron microscopy was used to study the biocidal action of this nanocatalyst, the results confirmed that the treated E. coli cells were damaged, the nanocatalyst permeated into cells and resulting in death of cells. Besides, it was found that the destruction of bacterial membrane together with substantial leaked potassium ion (K
) which caused by the photo-generated reactive species superoxide radical (O
) and holes (h
) could be the direct disinfection principles. For a deep insight into practical applications, the influences of different catalyst concentrations and reaction pH were also taken into discussion in details. The overall results indicated the novel photocatalyst with strong redox capacity and outstanding reusability can be widely employed in bacteria elimination.
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