Hallmarks of mechanochemistry: From nanoparticles to technology

The aim of this review article on recent developments of mechanochemistry (nowadays established as a part of chemistry) is to provide a comprehensive overview of advances achieved in the field of atomistic processes, phase transformations, simple and multicomponent nanosystems and peculiarities of mechanochemical reactions. Industrial aspects with successful penetration into fields like materials engineering, heterogeneous catalysis and extractive metallurgy are also reviewed. The hallmarks of mechanochemistry include influencing reactivity of solids by the presence of solid-state defects, interphases and relaxation phenomena, enabling processes to take place under non-equilibrium conditions, creating a well-crystallized core of nanoparticles with disordered near-surface shell regions and performing simple dry time-convenient one-step syntheses. Underlying these hallmarks are technological consequences like preparing new nanomaterials with the desired properties or producing these materials in a reproducible way with high yield and under simple and easy operating conditions. The last but not least hallmark is enabling work under environmentally friendly and essentially waste-free conditions (822 references).Slovak Grant Agency VEGA 2/0009/11, 2/0043/11Slovak Agency for Science and Development APVV VV-0189-10, VV-0528-11Russian Foundation for Basic Research 10-03-00942a, 12-03-00651aMinistry of Science and Higher education in Poland CUT/c-1/DS/KWC/2008-2012, PB1T09B02330, NN209145136, NN20914893

Effect of Mechanochemical Treatment on Magnetic Properties of Nanodimensional Magnetite-Type Materials

The presented study compares magnetic properties of Ni-doped magnetites $Ni_{0.5}^{2+}Fe_{0.5}^{2+}Fe_{2}^{3+}O_{4}$ to magnetite $(Fe_3O_4)$ sample. Physicochemical properties of materials were registered by means of X-ray powder diffraction, Mössbauer spectroscopy, saturation magnetization and physical properties measurement systems. It was obtained that used preparation procedures lead to synthesis of single phase spinel materials with close nanodimensional size about 8-12 nm. Mechanochemically synthesized sample shows better magnetic properties as lower blocking temperature of superparamagnetic state and minimal coercivity in comparison to other studied materials

Mechanochemical Preparation and Properties of Nanodimensional Perovskite Materials

The study is focused on the synthesis of $LaMO_3$ (M = Co, Fe, Mn) perovskite materials using combination of precipitation of precursors and mechanical milling at room temperature. Physicochemical properties of products at each step of preparation were studied by powder X-ray diffraction, Mössbauer spectroscopy, infrared spectroscopy (in the middle and far regions) and X-ray photoelectron measurements. As-prepared perovskite powders are composed of nanoparticles with very fine crystallite size (about 15 nm) in all cases. The materials have also high dispersion, high extent of microstrains and high level of oxygen vacancies which is very important in relevance to their use as heterogeneous catalysts

Reuse of Fe-based amorphous alloys containing CRM: study on their temperature behavior

In this paper, the physico chemical properties of Fe–based amorphous alloys containing critical raw materials (CRM) were investigated in order to reuse them for photocatalytic degradation of azo dyes. The iron-based metallic glasses were prepared by melt spinning method. Their chemical composition is: Fe67B14Co18Si, Fe78B15Mo2Si5 and Fe40B16Ni40Mo4. Characterization of the ribbons was done using combination of analytical methods. Studied materials were heated in inert atmosphere and in air at temperature of 1000 °C. Crystallization processes of investigated Fe–based amorphous alloys depending on their chemical composition were registered using thermal analysis. The changes of material phase composition and crystallinity degree were studied using powder X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The thermal treatment in inert atmosphere above the crystallization temperature of studied amorphous alloys result in rearrangement of iron neighbours and formation of multiphase crystalline structure, which strongly depends on the additive elements (Co, Ni, Mo). Heating of ribbons in air affects significantly the kinetic of crystallization and registered products in comparison to annealing in inert (argon) atmosphere. Investigation of thermal stability of ribbon metallic glasses and formation of different intermediate and product compounds is very important for practical application of damaged amorphous alloys, their further reuse and recycling

A study of the dispersity of iron oxide and iron oxide-noble metal (Me=Pd, Pt) supported systems

Samples of one-(Fe) and two-component (Fe-Pd and Fe-Pt) catalysts were prepared by incipient wetness impregnation of four different supports: TiO2 (anatase), gamma-Al2O3, activated carbon, and diatomite. The chosen synthesis conditions resulted in the formation of nanosized supported phases - iron oxide (in the onecomponent samples), or iron oxide - noble metal (in the two-component ones). Different agglomeration degrees of these phases were obtained as a result of thermal treatment. Ultradisperse size of the supported phase was maintained in some samples, while a process of partial agglomeration occurred in others, giving rise to nearly bidisperse (ultra- and highdisperse) supported particles. The different texture of the used supports and their chemical composition are the reasons for the different stability of the nanosized supported phases. The samples were tested as heterogeneous catalysts in total benzene oxidation reaction

Characterization of double oxide system Cu-Cr-O supported on gamma-Al2O3

Series of alumina supported chromium-copper catalysts were prepared by co-impregnation method. The samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and UV-visible diffuse reflectance spectroscopy. Dispersion and porosity was also obtained. The experimental and catalytic test results have drawn a conclusion that an interaction between copper and chromium ions takes place. This interaction is responsible for the enhanced catalytic activity of studied catalysts in reaction of total oxidation of industrial formaldehyde production exhaust gas, which contains CO, dimethyl ether and methanol as main components

Chapter Long-Distance LIDAR Mapping Schematic for Fast Monitoring of Bioaerosol Pollution over Large City Areas

Light detection and ranging (LIDAR) atmospheric sensing is a major tool for remote monitoring of aerosol pollution and its propagation in the atmosphere. Combining LIDAR sensing with ground-based aerosol monitoring can form the basis of integrated air-quality characterization. When present, biological atmospheric contamination is transported by aerosol particles of different size known as bioaerosol, whose monitoring is now among the basic areas of atmospheric research, especially in densely-populated large urban regions, where many bioaerosol-emitting sources exist. Thus, promptly identifying the bioaerosol sources, including their geographical coordinates, intensities, space-time distributions, etc., becomes a major task of a city monitoring system. This chapter argues in favor of integrating a LIDAR mapping schematic with in situ sampling and characterization of the bioaerosol in the urban area. The measurements, data processing, and decision-making aimed at preventing further atmospheric contamination should be performed in a near-real-time mode, which imposes certain demands on the typical LIDAR schematics, including long-range sensing as a critical parameter, especially over large areas (10 – 100 km2). In this chapter, we describe experiments using a LIDAR schematic allowing near-real-time long-distance measurements of urban bioaerosol combined with its ground-based sampling and physicochemical and biological studies