Sodium Doped LaMnO3 Thin Films: Influence of Substrate and Thickness on Physical Properties

In this paper we report the results about the synthesis and characterization of optimally doped La1-xNaxMnO3 thin films grown onto SrTiO3 (100), NdGaO3 (100) and NdGaO3 (110) for thickness ranging from 11 to 82 nm. The effect of substrate nature and orientation, film thickness and annealing procedure was investigated in order to optimize their magnetoresistance (MR). We obtained very smooth films displaying MR values greater than 70%, near to room temperature.Comment: 31 pages, 9 figures Final version to appear in J. Phys. Chem.

Chemical Analysis of Air Particulate Matter Trapped by a Porous Material, Synthesized from Silica Fume and Sodium Alginate

This work shows the ability of a new porous material (SUNSPACE), obtained by industrial by-products, to sequestrate air particulate matter (PM). This activity allows introducing the azure chemistry approach, devoted to better link new remediation strategies and sustainability. In particular, SUNSPACE is synthesized from silica fume and sodium alginate; it can be shaped in a porous solid, and it looks promising for environmental application as nanoparticle sequestration. Studies to evaluate the sequestration capability of SUNSPACE are performed in different environments, with and without anthropogenic sources of PM. Solid SUNSPACE disc samples are used as passive samplers and exposed for one and two months, in vertical and horizontal positions, indoor, and outdoor. Total reflection X-ray fluorescence technique is employed to perform elemental chemical analysis of the entrapped PM. Two sample preparation strategies to evaluate the composition of PM are considered: sample sonication in Milli-Q water and total sample mineralization by microwave acid digestion. These two options are proposed to analyse different PM fractions: in particular, sonication allows removing the coarse PM, entrapped on external material surface pores; on the contrary, digestion can offer information on fine and ultrafine PM, trapped in internal pores. Results confirm the ability of the porous material to sequestrate air PM and the differences in the sample preparation, supported by elemental analysis, and show the difference in the coarse and fine air particulate matter composition. In summary, the new material results as very promising for applications requiring nanoparticle sequestration

Accelerated Carbonation of Steel Slag and Their Valorisation in Cement Products: A Review

Mineral carbonation emerges as a promising technology to tackle a contemporary challenge: climate change. This method entails the interaction of carbon dioxide with metal-oxide-bearing materials to produce solid carbonates resembling common substances (chalk, antacids, or baking soda). Given that steelmaking industries contribute to 8% of the global total emissions annually, the repurposing of their by-products holds the potential to mitigate CO2 production. Steel slag is a by-product of the metallurgical industry which is suitable for capturing CO2 due to its chemical composition, containing high CaO (24%–65%) and MgO (3%–20%) amounts, which increases the reactivity with the CO2. Moreover, the carbonation process can improve the hydraulic and mechanical properties of steel slag, making this by-product interesting to be reused in building materials. Different studies have developed in the last years addressing the possibilities of reducing the environmental impact of steel products, by CO2 sequestration. This study is dedicated to reviewing the basics of mineral carbonation applied to steel slag, along with recent advancements in research. Special emphasis is placed on identifying parameters that facilitate the reactions and exploring potential applications for the resulting products. The advantages and disadvantages of steel slag carbonation for the industrialization of the process are also discussed

Utilization of Third-Stage Waste from a Rice Production for Removal of H2S, NO2 and SO2 from Air:

Materials derived from rice husk fly ash were tested as adsorbents of hydrogen sulphide, sulphur dioxide and nitrogen dioxide. Breakthrough experiments were carried out at ambient temperature either in dry or moist air. The second-stage waste obtained in the extraction of silica from fly ash using sodium hydroxide exhibits the better adsorption capacity compared with that of caustic-modified activated carbons. The high performance is related to the presence of residual sodium hydroxide and other metals such as calcium, which react with acidic gases forming corresponding salts. Moreover, a high dispersion of the alkali and alkaline earth metal sites in the mesopores renders the pH of the solution basic, aiding in the dissociation of hydrogen sulphide, thereby facilitating its oxidation. The oxidation of species is also catalyzed by the carbonaceous surface. While in the case of hydrogen sulphide and sulphur dioxide, water helps in acid-base reactions, the opposite effect is found for NO2. Because its react..

Growth and microstructural analysis of nanosized Y2O3 doped with rare-earths

Nanosized cubic Y2O3 samples, undoped and doped with 10 mol% Nd2O3, Eu2O3, Gd2O3, Tb2O3, Ho2O3 and Er2O3 (Y(1.8)Ln(0.2)O(3), where Ln=Nd, Eu, Gd, Tb, Ho or Er), were prepared by means of a controlled hydrolysis method in an aqueous solution containing ammonia, Y(NO3)(3) and Ln(NO3)(3) as precursors, and a surface modifier. The microstrain and the average size of the diffraction domains have been calculated from the XRD patterns and the results have been compared with those obtained by a combustion synthesis. It is shown that the cell parameter of the C-M2O3 (bcc structure related to the CaF2 structure; the M atom is 6-coordinated) structure of doped Y2O3 is correlated to the ion size of the dopant. The shape of the crystallites appears to be needle-like in all cases, while the microstrains depend on the dopant and are probably due to surface effect. XRD and Raman analysis show that, despite the heavy doping, only one phase in the Y2O3 powders is present. (C) 2000 Elsevier Science S.A. All rights reserved

Study of Microstrain and Stress in Non-Planar Palladium Membranes for Hydrogen Separation

Palladiums tubular membranes are developed to operate up to 400 °C, for the synthesis of H2 and for the separation of CO2 in Water Gas Shift (WGS) processes and reforming gas of methane [. Palladium has FCC lattice that allows the separation of hydrogen from carbon dioxide through a solution-diffusion mechanism [. To ensure high selectivity in the separation process, the functional Pd layer on the porous substrate of the membranes must have a microstructure with low defects and free from residual stresses [.MicroXRD measurements were performed to evaluate the effect of the stress-relief heat treatment, carried out for different time and temperatures, on the palladium layer. Microstrains were assessed before and after stress-relief by the Williamson-Hall method [. The use of microdiffraction was mandatory considering the tubular shape of membranes. The data were corrected for elastic anisotropy of palladium and the altered Williamson-Hall method was successfully applied.The XRD two-dimensional (2D) images and the integrated spectra collected from the samples allowed to study also the evolution of Pd microstructure and the reduction of micro-stresses due to stress relief. The results of the study allowed to identify the optimal thermal profile for the heat treatment of palladium membranes

SUNSPACE, A Porous Material to Reduce Air Particulate Matter (PM)

The World Health Organization reports that every year several million people die prematurely due to air pollution. Poor air quality is a by-product of unsustainable policies in transportation, energy, industry, and waste management in the world's most crowded cities. Particulate matter (PM) is one of the major element of polluted air. PM can be composed by organic and inorganic species. In particular, heavy metals present in PM include, lead (Pb), mercury (Hg), cadmium, (Cd), zinc (Zn), nickel (Ni), arsenic (As), and molybdenum (Mo). Currently, vegetation is the only existing sustainable method to reduce anthropogenic PM concentrations in urban environments. In particular, the PM-retention ability of vegetation depends on the surface properties, related to the plant species, leaf and branch density, and leaf micromorphology. In this work, a new hybrid material called SUNSPACE (SUstaiNable materials Synthesized from by-Products and Alginates for Clean air and better Environment) is proposed for air PM entrapment. Candle burning tests are performed to compare SUNSPACE with Hedera Helix L. leafs with respect to their efficacy of reducing coarse and fine PM. The temporal variation of PM10 and PM2.5 in presence of the trapping materials, shows that Hedera Helix L. surface saturates more rapidly. In addition, the capability of SUNSPACE in ultrafine PM trapping is also demonstrated by using titanium dioxide nanoparticles with 25 nm diameter. Scanning electron microscope (SEM) and Transmission electron microscope (TEM) images of SUNSPACE after entrapment tests highlight the presence of collected nanoparticles until to about 0.04 mm in depth from the sample surface. N2 physisorption measurements allow to demonstrate the possibility to SUNSPACE regeneration by washing

Co-Nanomet: Co-ordination of Nanometrology in Europe

Nanometrology is a subfield of metrology, concerned with the science of measurement at the nanoscale level. Today’s global economy depends on reliable measurements and tests, which are trusted and accepted internationally. It must provide the ability to measure in three dimensions with atomic resolution over large areas. For industrial application this must also be achieved at a suitable speed/throughput. Measurements in the nanometre range should be traceable back to internationally accepted units of measurement (e.g. of length, angle, quantity of matter, and force). This requires common, validated measurement methods, calibrated scientific instrumentation as well as qualified reference samples. In some areas, even a common vocabulary needs to be defined. A traceability chain for the required measurements in the nm range has been established in only a few special cases. A common strategy for European nanometrology has been defined, as captured herein, such that future nanometrology development in Europe may build out from our many current strengths. In this way, European nanotechnology will be supported to reach its full and most exciting potential. As a strategic guidance, this document contains a vision for European nanometrology 2020; future goals and research needs, building out from an evaluation of the status of science and technology in 2010. It incorporates concepts for the acceleration of European nanometrology, in support of the effective commercial exploitation of emerging nanotechnologies. The field of nanotechnology covers a breadth of disciplines, each of which has specific and varying metrological needs. To this end, a set of four core technology fields or priority themes (Engineered Nanoparticles, Nanobiotechnology, Thin Films and Structured Surfaces and Modelling & Simulation) are the focus of this review. Each represents an area within which rapid scientific development during the last decade has seen corresponding growth in or towards commercial exploitation routes. This document was compiled under the European Commission Framework Programme 7 project, Co-Nanomet. It has drawn together input from industry, research institutes, (national) metrology institutes, regulatory and standardisation bodies across Europe. Through the common work of the partners and all those interested parties who have contributed, it represents a significant collaborative European effort in this important field. In the next decade, nanotechnology can be expected to approach maturity, as a major enabling technological discipline with widespread application. This document provides a guide to the many bodies across Europe in their activities or responsibilities in the field of nanotechnology and related measurement requirements. It will support the commercial exploitation of nanotechnology, as it transitions through this next exciting decade

Integrated management of ash from industrial and domestic combustion : a new sustainable approach for reducing greenhouse gas emissions from energy conversion

This work supports, for the first time, the integrated management of waste materials arising from industrial processes (fly ash from municipal solid waste incineration and coal fly ash), agriculture (rice husk ash), and domestic activities (ash from wood biomass burning in domestic stoves). The main novelty of the paper is the reuse of wood pellet ash, an underestimated environmental problem, by the application of a new technology (COSMOS-RICE) that already involves the reuse of fly ashes from industrial and agricultural origins. The reaction mechanism involves carbonation: this occurs at room temperature and promotes permanent carbon dioxide sequestration. The obtained samples were characterized using XRD and TGA (coupled with mass spectroscopy). This allowed quantification of the mass loss attributed to different calcium carbonate phases. In particular, samples stabilized using wood pellet ash show a weight loss, attributed to the decomposition of carbonates greater than 20%. In view of these results, it is possible to conclude that there are several environmental benefits from wood pellet ash reuse in this way. In particular, using this technology, it is shown that for wood pellet biomass the carbon dioxide conversion can be considered negative