UV/Vis Light Induced Degradation of Oxytetracycline Hydrochloride Mediated byCo-TiO Nanoparticles.

Pharmaceuticals, especially antibiotics, constitute an important group of aquatic contaminants given their environmental impact. Specifically, tetracycline antibiotics (TCs) are produced in great amounts for the treatment of bacterial infections in both human and veterinary medicine. Several studies have shown that, among all antibiotics, oxytetracycline hydrochloride (OTC HCl) is one of the most frequently detected TCs in soil and surface water.

Effect of the degree of inversion on optical properties of spinel ZnFeO.

Spinel ferrites (T[M1-xFex]O[MxFe2-x]O4 with 0 ≤ x ≤ 1, where M is a bivalent metal ion and the superscripts denote tetrahedral and octahedral sites) are materials commonly used in electronics due to their outstanding magnetic properties. Thus, the effect of the degree of inversion, x, on these properties is well known. However, its effect on other properties of these materials has rarely been investigated in detail.

Multifunctional Gadolinium-Doped Mesoporous TiO Nanobeads: Photoluminescence, Enhanced Spin Relaxation, and Reactive Oxygen Species Photogeneration, Beneficial for Cancer Diagnosis and Treatment.

Materials with controllable multifunctional abilities for optical imaging (OI) and magnetic resonant imaging (MRI) that also can be used in photodynamic therapy are very interesting for future applications. Mesoporous TiO sub-micrometer particles are doped with gadolinium to improve photoluminescence functionality and spin relaxation for MRI, with the added benefit of enhanced generation of reactive oxygen species (ROS). The Gd-doped TiO exhibits red emission at 637 nm that is beneficial for OI and significantly improves MRI relaxation times, with a beneficial decrease in spin-lattice and spin-spin relaxation times.

Laser-flash-photolysis-spectroscopy: a nondestructive method?

Herein, we report the effect of the laser illumination during the diffuse-reflectance laser-flash-photolysis measurements on the morphological and optical properties of TiO powders. A grey-blue coloration of the TiO nanoparticles has been observed after intense laser illumination. This is explained by the formation of nonreactive trapped electrons accompanied by the release of oxygen atoms from the TiO matrix as detected by means of UV-vis and EPR spectroscopy.

Photocatalytic hydrogen production from biomass-derived compounds: a case study of citric acid.

Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by thermal hydrolysis of titanium(IV) bis(ammoniumlactato) dihydroxide aqueous solutions. The photocatalytic H2 production from aqueous citric acid (CA) solutions over Pt-loaded TiO2 has been investigated under different experimental conditions, that is, different CA concentration, temperature, light intensity, and pH of Pt/TiO2 suspension. For comparison, the photocatalytic dehydrogenation of triethanolamine (TEA) has also been investigated.

Mechanistic Features of the TiO2 Heterogeneous Photocatalysis of Arsenic and Uranyl Nitrate in Aqueous Suspensions Studied by the Stopped-Flow Technique.

The dynamics of the transfer of electrons stored in TiO2 nanoparticles to As(III) , As(V) , and uranyl nitrate in water was investigated by using the stopped-flow technique. Suspensions of TiO2 nanoparticles with stored trapped electrons (etrap (-) ) were mixed with solutions of acceptor species to evaluate the reactivity by following the temporal evolution of etrap (-) by the decrease in the absorbance at λ=600 nm. The results indicate that As(V) and As(III) cannot be reduced by etrap (-) under the reaction conditions.

Novel Microwave Thermodynamic Model for Alcohol with Clustering Structure in Nonpolar Solution.

A solution containing ethanol as polar material and either benzene or n-dodecane as nonpolar solvent was heated by microwave irradiation employing a single-mode resonance microwave device. Although the microwave heating efficiency was expected from the just value of the relative dielectric constant (εr') or relative dielectric loss (εr″) for liquid system, it was revealed that the clustering structure of alcohol molecules expected from the excess parameter such as the excess relative dielectric loss is the important factor in the decision for efficiency of the microwave heating for the solution. This assumption and novel theory were strongly supported from the thermodynamic data such as vapor pressure and the partial enthalpy.

Application of the Stopped Flow Technique to the TiO₂-Heterogeneous Photocatalysis of Hexavalent Chromium in Aqueous Suspensions: Comparison with O₂ and H₂O₂ as Electron Acceptors.

The dynamics of the transfer of electrons stored in TiO2 nanoparticles to Cr(VI) in aqueous solution have been investigated using the stopped flow technique. TiO2 nanoparticles were previously irradiated under UV light in the presence of formic acid, and trapped electrons (e(trap)(-)) were made to react with Cr(VI) as acceptor species; other common acceptor species such as O2 and H2O2 were also tested. The temporal evolution of the number of trapped electrons was followed by the decrease in the absorbance at 600 nm, and the kinetics of the electron-transfer reaction was modeled.

Microwave-driven asbestos treatment and its scale-up for use after natural disasters.

Asbestos-containing debris generated by the tsunami after the Great East Japan Earthquake of March 11, 2011, was processed by microwave heating. The analysis of the treated samples employing thermo gravimetry, differential thermal analysis, X-ray diffractometry, scanning electron microscopy, and phase-contrast microscopy revealed the rapid detoxification of the waste by conversion of the asbestos fibers to a nonfibrous glassy material. The detoxification by the microwave method occurred at a significantly lower processing temperature than the thermal methods actually established for the treatment of asbestos-containing waste.

Ruthenium-modified zinc oxide, a highly active vis-photocatalyst: the nature and reactivity of photoactive centres.

We recently reported a highly active photocatalyst, ruthenium-modified zinc oxide, which was found to be able to utilise the red part of the visible light spectrum for photocatalytic reactions [Bloh et al., Environ. Sci.

Self-cleaning properties, mechanical stability, and adhesion strength of transparent photocatalytic TiO(2)-ZnO coatings on polycarbonate.

Transparent layers containing TiO2 have been intensively studied because of their interesting application potential including photocatalytically active and self-cleaning surfaces. In the present work, transparent TiO2-ZnO thin films on a SiO2 interlayer were successfully deposited on the surface of polycarbonate to provide polymeric sheets with a self-cleaning, superhydrophilic, and photocatalytically active surface layer. To ensure a good adhesion of the SiO2 interlayer, the polycarbonate sheets were first modified by irradiation with UV(C) light.

Light intensity dependence of the kinetics of the photocatalytic oxidation of nitrogen(II) oxide at the surface of TiO2.

Air pollution by nitrogen oxides represents a serious environmental problem in urban areas where numerous sources of these pollutants are concentrated. One approach to reduce the concentration of these air pollutants is their light-induced oxidation in the presence of molecular oxygen and a photocatalytically active building material which uses titanium dioxide as the photocatalyst. Herein, results of an investigation concerning the influence of the photon flux and the pollutant concentration on the rate of the photocatalytic oxidation of nitrogen(ii) oxide in the presence of molecular oxygen and UV(A) irradiated titanium dioxide powder are presented.

Preparation and characterization of transparent hydrophilic photocatalytic TiO2/SiO2 thin films on polycarbonate.

Transparent hydrophilic photocatalytic TiO2 coatings have been widely applied to endow the surfaces self-cleaning properties. A mixed metal oxide (TiO2/SiO2) can enhance the photocatalytic performance improving the ability of surface adsorption and increasing the amount of hydroxyl surface groups. The present work introduces a systematic study concerning the effect of the SiO2 addition to TiO2 films on the wettability, the photocatalytic activity, the adhesion strength, and the mechanical stability of the films.

Factors affecting the selectivity of the photocatalytic conversion of nitroaromatic compounds over TiO2 to valuable nitrogen-containing organic compounds.

The photocatalytic conversion of various nitroaromatic compounds in alcohols employing four different types of TiO(2) (Sachtleben Hombikat UV100 as anatase, Crystal Global R34 as rutile, Evonik-Degussa Aeroxide P25 as an anatase-rutile mixture, and home-made mesoporous anatase) has been studied. The effect of platinization of these different types of TiO(2) on the reaction sequence has also been investigated. Upon irradiation of an ethanolic solution of m-nitrotoluene, as a model reaction, in the presence of the bare photocatalyst, different products were obtained according to the applied photocatalyst.

Kinetic and mechanistic investigations of the light induced formation of gold nanoparticles on the surface of TiO2.

The kinetics of the formation of gold nanoparticles on the surface of pre-illuminated TiO(2) have been investigated using stopped-flow technique and steady state UV/Vis spectroscopy. Excess electrons were loaded on the employed nanosized titanium dioxide particles by UV-A photolysis in the presence of methanol serving as hole scavenger, stored on them in the absence of oxygen and subsequently used for the reduction of Au(III) ions. The formation of gold nanoparticles with an average diameter of 5 nm was confirmed after mixing of the TiO(2) nanoparticles loaded with electrons with aqueous solution of tetrachloroaureate (HAuCl(4)) by their surface plasmon absorbance band at 530 nm, as well as by XRD and HRTEM measurements.

Influence of inlet concentration and light intensity on the photocatalytic oxidation of nitrogen(II) oxide at the surface of Aeroxide® TiO2 P25.

Air pollution by nitrogen oxides represents a serious environmental problem in urban areas where numerous sources of these pollutants are concentrated. One approach to reduce the concentration of these air pollutants is the light-induced oxidation in the presence of molecular oxygen and a photocatalytically active building material, e.g.

Kinetic and mechanistic investigations of multielectron transfer reactions induced by stored electrons in TiO2 nanoparticles: a stopped flow study.

The kinetics and the mechanism of various multielectron transfer reactions initiated by stored electrons in TiO(2) nanoparticles have been investigated employing the stopped flow technique. Moreover, the optical properties of the stored electrons in the TiO(2) nanoparticles have been studied in detail following the UV (A) photolysis of deaerated aqueous suspensions of TiO(2) nanoparticles in the presence of methanol. The reduction of common electron acceptors that are often present in photocatalytic systems such as O(2), H(2)O(2), and NO(3)(-) has been investigated.

Enhanced photocatalytic production of molecular hydrogen on TiO(2) modified with Pt-polypyrrole nanocomposites.

Titanium dioxide was modified with Pt-polypyrrole nanocomposites through the in situ simultaneous reduction of Pt(iv) and the oxidative polymerization of pyrrole monomers at ambient temperature. The modified powders were characterized using X-ray photoelectron spectroscopy (XPS), dark-field scanning transmission electron microscopy (DF-STEM), infrared spectroscopy (IR) and by the determination of the BET surface area by nitrogen adsorption. Photocatalytic hydrogen production tests were performed employing 75 ml aqueous solution containing 2250 mumol methanol as the sacrificial electron donor.

Light-induced degradation of perfluorocarboxylic acids in the presence of titanium dioxide.

The UV-photon-induced degradation of heptafluorobutanoic acid was investigated in acidic aqueous solutions in the presence of titanium dioxide. Heptafluorobutanoic acid could be degraded with this photocatalyst in a light-induced reaction generating carbon dioxide and fluoride anions. Carbon dioxide evolution in a significant amount occurred only in the presence of molecular oxygen and the photocatalyst.