Construction of stable photo-Fenton system with efficient removal capability of ciprofloxacin by accelerating in-situ photoreduction of Fe3+ in MIL-100(Fe).

Well-dispersed MIL-100(Fe) nanoparticles were synthesized under mild conditions and used to construct a photo-Fenton system (VMH system) with the assistance of visible-light irradiation and hydrogen peroxide. In such a VMH system, the MIL-100(Fe) has a high specific surface area and provides numerous Fe3+ active sites, thus accelerating the reaction of Fe3+ with photo-generated electrons under visible-light irradiation and generates Fe2+, and then the acquired Fe2+ can activate H2O2 to generate ⋅OH, accompanying with the oxidation of Fe2+ to Fe3+. Hence, the in-situ recycling of Fe2+/Fe3+ promotes the generation of ·OH, thus making the VMH system exhibits promising photocatalytic activity. The removal rate of ciprofloxacin in the VMH system is as high as 95.2% within 120 min photo-Fenton reaction, which is about 26 times higher than that of the Visible light/MIL-100(Fe) system. Moreover, the VMH system also exhibits strong degradation ability to other typical antibiotics, such as tetracycline, norfloxacin and cephalexin, and maintains high cyclic stability, revealing great practical application potential in the purification of antibiotic wastewater.

Oxygen vacancy regulation in Nb-doped Bi2WO6 for enhanced visible light photocatalytic activity.

Novel Nb-doped Bi2WO6 nanosheets have been successfully synthesized by a simple hydrothermal method. XRD, Raman spectra, XPS and SEM were adopted to analyze the structure and morphology of the samples, then the structure-dependent optical properties, photoelectric behavior and photocatalytic activities were investigated, and the structure-property relationship was also discussed. The results show that doping Nb5+ can increase the oxygen vacancies in the Bi2WO6 lattice and reduce the optical band gap of Bi2WO6. The oxygen vacancies also act as electron traps, which promote the separation of photogenerated carriers. Hence, compared with the pure Bi2WO6, the as-prepared Nb-doped Bi2WO6 nanosheets exhibit enhanced visible-light photocatalytic activity for removing contaminants in water such as rhodamine B and tetracycline.

NiCo2O4/NiCoP nanoflake-nanowire arrays: a homogeneous hetero-structure for high performance asymmetric hybrid supercapacitors.

Transition metal phosphides (TMPs) represent an important class of compounds with metalloid characteristics and good electrical conductivity, which are of great benefit to enhance electrochemical performances. Thus it is important to clarify the correlation between the electrochemical properties and the phosphating degree of the precursor. Herein, we report a superior electrode for battery-like capacitors based on NiCo2O4/NiCoP hetero-structure nanoflake-nanowire arrays grown on nickel foams using a one-pot facile hydrothermal approach and a controllable phosphorization treatment method. The Ni-Co precursor nanoflake-nanowire array based electrode treated with 500 mg NaH2PO2 shows significantly improved electrochemical performances with an ultrahigh specific capacitance of 2288.8 F g-1 and 1644 F g-1 at a current density of 1 A g-1 and 20 A g-1, respectively. The electrode also shows superior cycling stability. In addition, the NiCo2O4/NiCoP//AC device exhibits a relatively high energy density of 35.5 W h kg-1 at 750.4 W kg-1. The results suggest that this NiCo2O4/NiCoP nanoflake-nanowire array is a promising electrode material for high performance hybrid supercapacitor applications.

A novel efficient g-C3N4@BiOI p-n heterojunction photocatalyst constructed through the assembly of g-C3N4 nanoparticles.

An efficient and facile method to fabricate a surficial dispersive heterojunction based on the assembly of g-C3N4 nanoparticles was proposed. A p-n nano heterojunction composed of BiOI and g-C3N4 was constructed by simply loading g-C3N4 nanoparticles on flower-like BiOI nanosheets. The structure-dependent optical, electronic and photoelectric properties were investigated, and the structure-property relationship was discussed. The results show that the g-C3N4 nanoparticles are uniformly loaded on the surface of BiOI nanosheets and thus form a p-n heterojunction with an intimate interface. The as-prepared samples exhibit enhanced photocatalytic degradation ability towards MO under visible-light irradiation. With the unique structure and morphology, enhanced visible-light photocatalytic activities are achieved owing to the synergistic effect of light harvesting, high transfer efficiency and enhanced separation efficiency of photo-generated carriers.

Bactericidal mechanisms and effector targets of TiO2 and Ag-TiO2 against Staphylococcus aureus.

PURPOSE: In our previous study, Ag+-loaded TiO2 and Ag+-loaded SiO2 coatings for tracheal intubation were prepared to prevent ventilator-associated pneumonia (VAP), but the antimicrobial targets and the underlying mechanisms of TiO2 and Ag-TiO2 (Ag+) are still unclear. We attempted to elucidate the antimicrobial activity and potential mechanisms against Staphylococcus aureus. METHODOLOGY: The study tested the TiO2 and Ag+ bacteriostatic activity against S. aureus strains by MIC assays and S. aureus growth curves, lesion in the membranes by surface hydrophobicity tests, conductivity tests and measurements of DNA and RNA contents in S. aureus cultures, and investigated the inhibition of soluble protein and nucleic acid synthesis by measurements of soluble protein content, fluorescent intensity and nucleic acid content of living S. aureus. RESULTS: The MIC values of TiO2 and Ag+ were 1.6 mg ml-1 and 5.781 µg ml-1. TiO2 and Ag+ could inhibit the growth of S. aureus. After treatment with TiO2 and Ag+, the surface hydrophobicity was significantly reduced, the conductivity of cultures increased, and DNA and RNA content in cultures showed no obvious changes. The expressions of soluble proteins and nucleic acid contents of living S. aureus were reduced after treatment with TiO2 and Ag+. CONCLUSION: TiO2 and Ag+ could cause slight lesion in the membrane to affect S. aureus membrane permeability, but not decomposition of membrane. Moreover, TiO2 and Ag+ could lead to reduced expression of soluble protein by inhibiting the synthesis of nucleic acids, thereby further inhibiting the growth of S. aureus.

Preparation of silicon-modified antimicrobial polyethylene endotracheal tubes.

Antimicrobial coating of polyethylene endotracheal tubes (PE ETTs) has proven to be an effective method to prevent endoluminal biofilm formation. A transparent silicon-modified antimicrobial PE ETT was obtained by coating PE with a SiO2 /γ-methacryloxypropyl trimethoxy silane (KH-570)/methyltriethoxysilane (MTES)/Ag-SiO2 solution prepared by chemically mixing Ag-SiO2 with SiO2 /KH-570/MTES in solution via a dip-coating method, with tetraethyl orthosilicate (TEOS) as the inorganic silicon source, followed by drying. All the films were characterized by various techniques, including the pencil hardness test, infrared spectroscopy, scanning electron microscopy, UV-vis analysis, and inductively coupled plasma mass spectrometry (ICP-MS). The results indicated that the TEOS/KH-570/MTES/Ag-SiO2 (15:6:1:0.6-1.0) films, which exhibited simple in-solution film formation on PE ETTs, had a homogeneous morphology, high transmittance above 87%, high hardness of 5H and strong adhesion to the tubes. The concentration of Ag+ ion dissolved out from the antibacterial coating is very low in ICP-MS results. The antibacterial test results show that the antibacterial coatings have excellent antibacterial property with antibacterial ratio up to 93.5% when Ag-SiO2 content is 2.6%. In pyrogen test and hemolytic test, the body temperature of rabbits rise 0.03°c for 3 h after inserting antibacterial PE ETT, and the hemolytic ratio is 0.7512%, which conform to the requirements of biomedical material. The results preliminarily proved that the antibacterial materials could be a good candidate of medical catheter material application or medical device surface coating materials. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 91-98, 2017.

A hydrothermal synthesis of Pr3+ doped mesoporous TiO2 for UV light photocatalysis.

Pr3+ doped mesoporous TiO2 photocatalysts with a different molar ratio of Pr to Ti were prepared by a hydrothermal method using triblock copolymer as the template. The as-prepared samples were systematically characterized by X-ray diffraction, N2 adsorption-desorption, X-ray photoelectron spectra, transmission electron microscopy and UV-visible diffuse reflectance spectroscopy. The characterizations indicated all the samples had mesoporous structure and narrow pore size distribution. Pr3+ doping enlarged the surface area and decreased the crystallite size. The surface area of the samples varied from 136 to 170 m2/g, and the average crystallite size ranged between 5.04 and 7.60 nm. The effect of Pr3+ doping amount on the photocatalytic activity of mesoporous TiO2 was evaluated by the degradation of methyl orange under UV light irradiation. The results showed that the suitable amount of Pr3+ doped samples exhibited the higher photocatalytic activity than mesoporous TiO2. Among the samples, 1 at.% Pr3+ doped mesoporous TiO2 showed the highest photocatalytic activity.