Non-modified (ZnO) and modified (Fe2O3@ZnO and CuO@ZnO) structured films are deposited via aerosol assisted chemical vapor deposition. The surface modification of ZnO with iron or copper oxides is achieved in a second aerosol assisted chemical vapor deposition step and the characterization of morphology, structure, and surface of these new structured films is discussed. X-ray photoelectron spectrometry and X-ray diffraction corroborate the formation of ZnO, Fe2O3, and CuO and the electron microscopy images show the morphological and crystalline characteristics of these structured films. Static water contact angle measurements for these structured films indicate hydrophobic behavior with the modified structures showing higher contact angles compared to the non-modified films. Overall, results show that the modification of ZnO with iron or copper oxides enhances the hydrophobic behavior of the surface, increasing the contact angle of the water drops at the non-modified ZnO structures from 122° to 135° and 145° for Fe2O3@ZnO and CuO@ZnO, respectively. This is attributed to the different surface properties of the films including the morphology and chemical composition.

A new functionalized dicationic ionic liquid was synthesized with the final aim of studying its application in the extraction of metal ions in the mineral industry. In light of this application, the density, refractive index, and dynamic viscosities have been determined and correlated as a function of temperature. Density data were used to calculate the volumetric properties of the ionic liquid. Several empirical equations were used to evaluate the correlation between the density and refractive indices. The results show that the modified Eykman equation has the best fit. In addition, thermal behavior was measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and a high thermal stability and a wide liquid phase range were determined.

-In Chile, the most important economic activity is mining, concentrated in the north of the country. This is a desert region with limited water resources; therefore, the mining sector requires research and identification of alternative sources of water. One alternative is seawater, which can be a substitute of the limited fresh water resources in the region. This work determines the influence of seawater on the solid−liquid equilibrium for acid solutions of copper sulfate at different temperatures (293.15 to 318.15 K), and its effect on physical properties (density, viscosity, and solubility). Knowledge of these properties and solubility data are useful in the leaching process and in the design of copper sulfate pentahydrate crystallization plants from the leaching process using seawater by means of the addition of sulfuric acid.

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This review presents the fundamentals of photoactivated gas sensing, materials, and enabling technologies for sensing ppb concentrations of NO2. Literature photoactivated gas sensors show competitive detection limits and form factors.

Zinc oxide rod structures are synthetized and subsequently modified with Au, Fe2O3, or Cu2O to form nanoscale interfaces at the rod surface. X-ray photoelectron spectroscopy corroborates the presence of Fe in the form of oxide—Fe2O3; Cu in the form of two oxides—CuO and Cu2O, with the major presence of Cu2O; and Au in three oxidation states—Au3+, Au+, and Au0, with the content of metallic Au being the highest among the other states. These structures are tested towards nitrogen dioxide, ethanol, acetone, carbon monoxide, and toluene, finding a remarkable increase in the response and sensitivity of the Au-modified ZnO films, especially towards nitrogen dioxide and ethanol. The results for the Au-modified ZnO films report about 47 times higher response to 10 ppm of nitrogen dioxide as compared to the non-modified structures with a sensitivity of 39.96% ppm−1 and a limit of detection of 26 ppb to this gas. These results are attributed to the cumulative effects of several factors, such as the presence of oxygen vacancies, the gas-sensing mechanism influenced by the nano-interfaces formed between ZnO and Au, and the catalytic nature of the Au nanoparticles.

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