Mixed-Metal MOF-Derived Carbon Sponges for Oil Absorption.

AIMS: In this work, we propose the implementation of three carbon sponges, generated from the carbonization of melamine-formaldehyde sponges coated with different HKUST-type metal-organic frameworks (MOFs) in different thermal conditions. BACKGROUND: Nowadays, numerous investigations are focused on the development of new technologies for the rapid separation of water/oil mixtures. Several of these processes use hydrophobic materials of different nature for efficient oil capture. Despite these efforts, the water/oil separation still remains a great challenge. The main oil absorbers that are commercially available tend to be expensive and have complex synthesis; however, they usually have an acceptable cost/benefit ratio. Despite this, the passage of time has brought us new generations of materials, which seek to solve the problems in a more efficient way, as in the case of metal-organic frameworks (MOFs), which stand out for the great ease with which their morphological and surface aspects can be controlled. MOFs are extensively investigated in the fields of adsorption and catalysis; the MOF coated sponges do not meet the selectivity and stability standards to be applied in oil spills in water. However, this completely changes when subjected to the pyrolysis process, giving the material an increase in its surface area, hydrophobic and magnetic properties in addition to making the material suitable for its application. OBJECTIVE: Creation of a low-cost 3D template and the study of morphological properties of MOFs, for the formation of carbon-based materials by a fast, simple and low-cost method, promoting the use of new generations of materials to more effectively solve persistent environments. METHODS: The employed MOF precursors were trimesic acid (BTC), nickel and cobalt salts. The monometallic HKUST type MOFs were synthesized using a simple method of controlled precipitation, which starts from two precursor solutions. The first one consisted of a ligand solution, dissolving the BTC in deionized water. In the case of mixed-metal MOFs, they were synthesized using the same procedure described for monometallic MOFs, but in this case, a mixture of metal salts with a 1:1 molar ratio was performed. The methodology for the production of the sponges decorated with MOF was carried out in two steps. In the first stage, the sponges were subjected to a wash to remove dust and impurities, being rinsed with acetone in an ultrasonic bath for 30 min. The sponges were subsequently immersed in deionized water and subjected to an ultrasonic bath for 10 min. Finally, the sponges were dried at 60°C for 3 h. The second step was the addition of the HKUST-type MOFs to the sponges was carried out by means of the immersion method, preparing a dispersion of the corresponding MOFs in ethanol. RESULTS: It was revealed that the carbon sponges can selectively absorb oil in the water/oil mixture, possessing magnetic and enhanced hydrophobic and superhydrophobic properties. All the pyrolyzed carbon sponges, obtained at 500 and 700°C, were not the most optimal since they had absorption capacities of around 25 g/g and only supported up to 4 absorption cycles. On the other hand, the carbon sponges, obtained at 300°C, had absorption capacities greater than 40 g/g, in addition to being able to be reused up to 12 times without showing significant changes in their absorption capacity and having acceptable hydrophobic characteristics for the removal of oil dispersed in water. Among the three sponges obtained at 300°C, we highlight the sponges coated with BTC-Co, which have the highest absorption capacity (54 g/g) among all fabricated sponges. CONCLUSIONS: The sponges obtained in the present work are a promising alternative to the materials that are traditionally used since they have great advantages such as their simple production method, low-cost starting materials and good absorption capacities. This work sheds light on the production of carbon materials from 3D templates decorated with MOFs, through a one-step carbonization process and we demonstrate that these materials have characteristics that make them applicable in the removal of oil dispersed in water, giving us a practical, economic and friendly alternative to the environment.

Tapered Optical Fiber Detector for a Red Dye Concentration Measurement.

BACKGROUND: In this work, a detector based on optical fiber covered with Multi-Wall Carbon Nanotubes (MWCNTs) was used for sensing and removal of Alizarin from wastewaters. Alizarin is a strong anionic red dye that is part of the anthraquinone dye group. As a rule, this dye is used in the textile industry as a coloring agent. Experiments showed a good efficiency of wastewater treatment. This development could resolve the problem of water contamination with Alizarin red dye. METHODS: We used a single-mode fiber SMF-28e with a core diameter of 8.2 µm and a cladding diameter of 125 µm as a base for the tapered optical fiber detector. An MWCNTs array was synthesized on the tapered optical fiber detector surface by spray pyrolysis Chemical Vapor Deposition (CVD) method at 800oC for 20 min inside a tubular furnace, using ferrocene solution in toluene as a catalyst precursor. The formed structure was applied for Alizarin detection in water. RESULTS: According to the patent studies, the nanotubes completely covered the optical fiber surface and the array had a high density with minimal distance between nearby nanotubes. Carbon nanotubes were oriented along the radius of the optical fiber. The average diameter of carbon nanotubes was 24 nm. The optical absorbance levels increased as the Alizarin concentration increased from 50 mg/L to 1000 mg/L. MWCNTs on the optical fiber tapered section adsorbed the dye molecules from aqueous solution. Three intensive absorption bands with the wavelength of the 700, 714 and 730 nm appeared and their intensity increased as the Alizarin concentration increased. The accumulated Alizarin can be recovered by multiple immersing clean water. This property may make tapered optical fiber detector reusable and increase the economic expediency of the sensor application. CONCLUSION: The study showed higher Alizarin adsorption efficiency of the tapered optical fiber detector compared with relative detectors. This structure can be reusable for dye detection. Removal efficiency for Alizarin reached 98.6%, which makes the tapered optical fiber detector promising for wastewater treatment and dye elimination.

Development of Sorbent Materials based on Polymer Waste and their Compounds with Nanomaterials for Oil Spill Remediation.

AIMS: The purpose of this work was to obtain a hydrophobic sorbent material with potential applications in oil spill remediation. BACKGROUND: The accidents due to oil spills cause long-term ecological damage, especially in the aquatic environment. The cleaning of oil spills can be carried out by many methods and techniques, being absorbents the most attractive due to the possibility of recovery and complete elimination of the hydrocarbons in situ from the water surface. In recent years, interest in polymeric materials for oil spill remediation has increased due to its low cost, high stability, and recyclability. OBJECTIVE: The objective of this work was the development of sorbent materials based on polymer wastes, such as Polyethylene Terephthalate (PET), obtained from recycled bottles, and recycled Polyurethane (PU), for its application in the recovery of oil spills. METHODS: Sorbent materials were prepared from polymer wastes, using salt molds for the formation of porous materials with a composition of PU of 5, 10 and 15%, which were subsequently hydrophobized using carbon nanotubes or silica nanoparticles by dip-coating technique. RESULTS AND DISCUSSION: The obtained hydrophobic sorbent materials were characterized by Scanning Electron Microscopy (SEM) and Infrared Spectroscopy (FTIR). The resulting absorbent has shown capacity to separate oil from water; the best result was obtained by the sponge of PET-PU (10% PU) hydrophobized with a suspension with low multi-wall carbon nanotubes (MWCNTs) concentration, obtaining an absorption capacity of 2.01 g/g. CONCLUSION: Besides the standard sorption capacity, these cheap sorbent materials had interesting properties like low density, high hydrophobicity and buoyancy, which could be applied in other applications related to solving oil spills.

Preparation of Tubular Forest-like and Other Carbon Structures Using Distinct Carbon Sources and Catalyst Concentrations.

BACKGROUND: In this work, various carbon nanotubes (MWCNTs) were synthetized by the spray pyrolysis method. Resulting nanoforest-like and bamboo-like carbon nanotubes, as well as Yjunctions of carbon nanotubes, possess different shapes and morphology, depending on the kind of carbon source used and on the number of iron particles on the furnace tube surface, which derives from various concentrations of ferrocene catalyst. METHODS: We used the spray pyrolysis method, using different carbon sources (n-pentane, n-hexane, nheptane, and acrylonitrile) as precursors and two different concentrations of ferrocene as a catalyst. Reactions of hydrocarbon decomposition were carried out at 800oC. The solution (hydrocarbon and catalyst) was introduced with a syringe, with a flow of 1 mL/min and the synthesis time of 20 min. Argon was used as carrier gas (1000 L/min). Preheater and oven temperatures were selected 180°C and 800°C, respectively, for each carbon source. The solution passed into a quartz tube placed in an oven. RESULTS: According to the studies of carbon nanostructures, obtained from different precursors, it can be proposed that the structures synthesized from n-pentane, n-hexane and n-heptane are formed by the root growth method. The growth mechanism of MWCNTs was studied, confirming that the root growth formation of products takes place, whose parameters also depend on furnace temperature and gas flow rate. Dependence of interlayer distance (0.34-0.50 nm) in the formed MWCNTs on precursors and reaction conditions is also elucidated. The formation of carbon nanotubes does not merely depend on carbon precursors but also has strong correlations with such growth conditions as different catalyst concentrations, furnace temperature and gas flow rate. Such parameters as the amount of catalyst and synthesis time are also needed to be considered, since they are important to find minor values of these parameters in the synthesis of forest-like carbon nanotubes and other structures such as bamboo-like carbon nanotubes and Y-junctions in carbon nanotubes. CONCLUSION: As a result of the evaluation of interlayer distance in CNTs formed from different carbon sources, a standard value of interlayer distance normally for CNTs is 0.34 nm and for pentane A (0.5 wt.%), hexane B (1 wt.%), toluene A (0.5 wt.%) the range is from 0.33 to 0.35 nm. In case of pentane and acrylonitrile, under an increase of the catalyst concentration, an increase of the value of interlayer distance takes place from 0.35 and 0.4 to 0.4 and 0.5 nm, respectively, but for hexane, heptane and cyclohexane, an increase of the catalyst concentration maintains the same interlayer distance. This involves the use of lower quantities of raw materials and, therefore less cost for obtaining these materials.

Greener synthesis of chemical compounds and materials.

Modern trends in the greener synthesis and fabrication of inorganic, organic and coordination compounds, materials, nanomaterials, hybrids and nanocomposites are discussed. Green chemistry deals with synthesis procedures according to its classic 12 principles, contributing to the sustainability of chemical processes, energy savings, lesser toxicity of reagents and final products, lesser damage to the environment and human health, decreasing the risk of global overheating, and more rational use of natural resources and agricultural wastes. Greener techniques have been applied to synthesize both well-known chemical compounds by more sustainable routes and completely new materials. A range of nanosized materials and composites can be produced by greener routes, including nanoparticles of metals, non-metals, their oxides and salts, aerogels or quantum dots. At the same time, such classic materials as cement, ceramics, adsorbents, polymers, bioplastics and biocomposites can be improved or obtained by cleaner processes. Several non-contaminating physical methods, such as microwave heating, ultrasound-assisted and hydrothermal processes or ball milling, frequently in combination with the use of natural precursors, are of major importance in the greener synthesis, as well as solventless and biosynthesis techniques. Non-hazardous solvents including ionic liquids, use of plant extracts, fungi, yeasts, bacteria and viruses are also discussed in relation with materials fabrication. Availability, necessity and profitability of scaling up green processes are discussed.

Metal Phthalocyanines as Catalyst Precursors of Metallated Carbon Nanotubes.

BACKGROUND: The addition of nanoparticles to cellulose paper can improve its mechanical strength, chemical stability, biocompatibility and hydrophobic properties. Silica nanoparticles are known to be inert, hydrophobic, biocompatible, biodegradable and have a good distribution being deposited on surfaces. The main characteristics of 20 nm SiO2 nanoparticles are good chemical and thermal stability with a melting point of 1610-1728°C, a boiling point of 2230°C with a purity of 99.5%. OBJECTIVE: To carry out the hydrophobization of paper based on Kraft cellulose and on cellulose obtained from soybean husk with 20-nm size SiO2 nanoparticles and to study hydrophobicity, morphology and topography of the prepared composites. Few relevant patents to the topic have been reviewed and cited. METHODS: The ground and roasted soybean husk was treated with a NaOH, washed and dried. Hydrophobization of paper was carried in aqueous medium by SiO2 addition in weight ratios "paper-SiO2 " of 0.01-0.05 wt.%, stirring, filtration and drying. The obtained cellulose sheet composites were characterized by Scanning Electron Microscopy (SEM), Transmisión Electron Microscopy (TEM), FTIRspectroscopy, Mullen proofs of hydrophobicity, and contact angle measurements. RESULTS: The mechanical properties of paper nanocomposites (tensile strength and compression) increased considerably by varying the concentrations. The tensile strength increased by 41-46% and the compressive strength increased by 55-56%. The existence of fiber nanofoils, good adhesion of 20-nm SiO2 nanoparticles to the paper surface, and their homogeneous distribution were observed. CONCLUSION: Cellulose was successfully obtained from soybean husk, applying the alkaline-based extraction method. A good reinforcement of cellulose fibers is observed due to the outstanding characteristics of the silicon dioxide nanoparticles.

Hydrophobization of Kraft-type Cellulose and Microfiber Cellulose Obtained from Soybean Husk in Ultrasonic Field.

BACKGROUND: The addition of nanoparticles to cellulose paper can improve its mechanical strength, chemical stability, biocompatibility and hydrophobic properties. Silica nanoparticles are known to be inert, hydrophobic, biocompatible, biodegradable and have a good distribution in being deposited on surfaces. The main characteristics of 20 nm SiO2 nanoparticles are good chemical and thermal stability with a melting point of 1610-1728°3C, a boiling point of 2230°C with a purity of 99.5%. OBJECTIVE: To carry out the hydrophobization of paper based on Kraft cellulose and on cellulose obtained from soybean husk with 20-nm size SiO2 nanoparticles and to study hydrophobicity, morphology and topography of the prepared composites. METHODS: The ground and roasted soybean husk was treated with a NaOH, washed and dried. Hydrophobization of paper was carried in aqueous medium by SiO2 addition in weight ratios "paper-SiO2" of 0.01-0.05 wt.%, stirring, filtration and drying. The obtained cellulose sheet composites were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), FTIRspectroscopy, Mullen proofs of hydrophobicity, and contact angle measurements. RESULTS: The mechanical properties of paper nanocomposites (tensile strength and compression) increased considerably by varying the concentrations. The tensile strength increased by 41-46% and the compressive strength increased by 55-56%. The existence of fiber nanofoils, good adhesion of 20-nm SiO2 nanoparticles to the paper surface, and their homogeneous distribution were observed. CONCLUSION: Cellulose was successfully obtained from soybean husk, applying the alkaline-based extraction method. A good reinforcement of cellulose fibers is observed due to the outstanding characteristics of the silicon dioxide nanoparticles.

A Comparison of Different Methods of MWCNTs Metalation in a Single Step Using Three Different Silver-containing Compounds.

BACKGROUND: Synthesis and applications of Ag-coated carbon nanotubes are currently under intensive research, resulting in a series of recent patents. Silver nanoparticles are normally obtained from silver nitrate. However, there are also other silver-containing compounds that can facilitate the production of silver nanoparticles, such as silver(I) acetate and silver(II) oxide. Being combined with carbon nanotubes, silver nanoparticles can transfer to them some of their useful properties, such as conductivity and antibacterial properties, and contribute to improving their dispersion in solvents. OBJECTIVE: To apply three different silver-containing precursors of Ag nanoparticles for the decoration of carbon nanotubes and study the morphology of formed composites by several methods. METHOD: Three different silver compounds were used as Ag source to carry out the functionalization and decoration of carbon nanotubes under ultrasonic treatment of the reaction system, containing, commercial carbon nanotubes, organic peroxides as oxidants or hydrazine as a reductant, and a surfactant. Resulting samples were analyzed by XRD and XPS spectroscopy, as well as TEM and SEM microscopy to study the morphology of formed nanocomposites. RESULTS: Silver nanoparticles can be produced without the presence of a reducing agent. Applying hydrazine, as a reducing agent, it is possible to obtain functionalized carbon nanotubes doped with silver nanoparticles, in which their sizes are smaller (1-5 nm) compared to those obtained without using hydrazine. CONCLUSION: Silver nanoparticles having a size range between 2-60 nm can be produced without the presence of a reducing agent. The use of a reducing agent, such as hydrazine, affects the size of silver nanoparticles.

Less-Common Nanostructures: Nanobuds: A Micro-Review.

BACKGROUND: Synthesis, properties, structural peculiarities, and applications of nanobuds and related nanostructures are discussed. In addition, few relevant patents to the topic have been reviewed and cited. According to observed properties and those predicted by DFT calculations, the nanobuds are semiconducting and stable in normal conditions, can accept adatoms and molecules. They contain a relatively chemically inert carbon nanotubes and more active fullerene species and can be compatible with a variety of other materials, in particular polymers. In addition to nanobuds for SWCNTs, the nanobuds with graphene, small fullerenes or metal nanobud-like structures are also known. METHOD: We have undertaken an extensive search of bibliographic databases for peer-reviewed research literature using a focused review question and inclusion/exclusion criteria. The characteristics of screened papers were described and critically compared. RESULTS: Thirty-six papers were included in the review, mainly from high-impact international journals. The published articles correspond to the range 2006-2016; the term "nanobuds" appeared in 2006 after their discovery. The reports included approaches of the synthesis of carbon nanobuds, their formation mechanism, in situ engineering, different modes of attachment of fullerene on carbon nanotubes, DFT and MD calculations, nanobuds containing small fullerenes and graphene nanobuds, information about related noble metal nanobuds, and applications of carbon nanobuds. CONCLUSION: The findings of this review confirm the importance of novel less-common nanostructures on the basis of carbon for fundamental science, their unusual properties and current and possible applications.

Coinage Metal Pyrazolates [(3,5-(CF3)2Pz)M]3 (M = Au, Ag, Cu) as Buckycatchers.

The synthesis and characterization of supramolecular assemblies {C60[M3]4}∞ consisting of C60 and coinage metal pyrazolates [M3] (i.e., [(3,5-(CF3)2Pz)M]3, where Pz = pyrazolate and M = Au, Ag, and Cu) are reported. {C60[Cu3]4}∞, {C60[Ag3]4}∞ and {C60[Au3]4}∞ form isomorphous crystals. The [M3] moieties adopt a concave conformation to complement the convex C60 surface. They exist as dimers of trimers (i.e., hexanuclear [M3]2 units) that are held together by three close M···M metallophilic interactions at 3.1580(17), 3.2046(7), and 3.2631(7) Å for copper, silver, and gold systems, respectively. The [M3]2 moieties surround each C60 in a tetrahedral fashion, while each [M3]2 is sandwiched by two C60 molecules to form a supramolecular 3D assembly.

Metal complexes containing natural and and artificial radioactive elements and their applications.

Recent advances (during the 2007-2014 period) in the coordination and organometallic chemistry of compounds containing natural and artificially prepared radionuclides (actinides and technetium), are reviewed. Radioactive isotopes of naturally stable elements are not included for discussion in this work. Actinide and technetium complexes with O-, N-, N,O, N,S-, P-containing ligands, as well π-organometallics are discussed from the view point of their synthesis, properties, and main applications. On the basis of their properties, several mono-, bi-, tri-, tetra- or polydentate ligands have been designed for specific recognition of some particular radionuclides, and can be used in the processes of nuclear waste remediation, i.e., recycling of nuclear fuel and the separation of actinides and fission products from waste solutions or for analytical determination of actinides in solutions; actinide metal complexes are also usefulas catalysts forcoupling gaseous carbon monoxide,as well as antimicrobial and anti-fungi agents due to their biological activity. Radioactive labeling based on the short-lived metastable nuclide technetium-99m ((99m)Tc) for biomedical use as heart, lung, kidney, bone, brain, liver or cancer imaging agents is also discussed. Finally, the promising applications of technetium labeling of nanomaterials, with potential applications as drug transport and delivery vehicles, radiotherapeutic agents or radiotracers for monitoring metabolic pathways, are also described.

Radioactive nanoparticles and their main applications: recent advances.

Selected nanoparticles and nanocomposites on the basis of radioactive elements are reviewed. Isotopes of metallic gold, iodine and technetium salts, CeO2 and other lanthanide and actinide compounds, as well as several p- (P, C, F, Te) and d- (Fe, Co, Cu, Cd, Zn) elements form most common radioactive nanoparticles. Methods for their fabrication, including dopation with radionuclides and neutron/proton/deuteron activation, are discussed. These nanocomposites possess a series of useful applications, in particular in biology and medicine, including cancer therapeutics, drug delivery systems and radiotracers, as well as in the studies of several catalytic processes and materials structure.

The greener synthesis of nanoparticles.

In this review, we examine 'greener' routes to nanoparticles of zerovalent metals, metal oxides, and salts with an emphasis on recent developments. Products from nature or those derived from natural products, such as extracts of various plants or parts of plants, tea, coffee, banana, simple amino acids, as well as wine, table sugar and glucose, have been used as reductants and as capping agents during synthesis. Polyphenols found in plant material often play a key role in these processes. The techniques involved are simple, environmentally friendly, and generally one-pot processes. Tea extracts with high polyphenol content act as both chelating/reducing and capping agents for nanoparticles. We discuss the key materials used in the field: silver, gold, iron, metal alloys, oxides, and salts.

Preparation and Characterization of Cu and Ni on Alumina Supports and Their Use in the Synthesis of Low-Temperature Metal-Phthalocyanine Using a Parallel-Plate Reactor.

Ni- and Cu/alumina powders were prepared and characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), and N2 physisorption isotherms were also determined. The Ni/Al2O3 sample reveled agglomerated (1 µm) of nanoparticles of Ni (30-80 nm) however, NiO particles were also identified, probably for the low temperature during the H2 reduction treatment (350 °C), the Cu/Al2O3 sample presented agglomerates (1-1.5 µm) of nanoparticles (70-150 nm), but only of pure copper. Both surface morphologies were different, but resulted in mesoporous material, with a higher specificity for the Ni sample. The surfaces were used in a new proposal for producing copper and nickel phthalocyanines using a parallel-plate reactor. Phthalonitrile was used and metallic particles were deposited on alumina in ethanol solution with CH3ONa at low temperatures; ≤60 °C. The mass-transfer was evaluated in reaction testing with a recent three-resistance model. The kinetics were studied with a Langmuir-Hinshelwood model. The activation energy and Thiele modulus revealed a slow surface reaction. The nickel sample was the most active, influenced by the NiO morphology and phthalonitrile adsorption.

Computational chemistry calculations of stability for bismuth nanotubes, fullerene-like structures and hydrogen-containing nanostructures.

Using molecular mechanics (MM+), semi-empirical (PM6) and density functional theory (DFT) (B3LYP) methods we characterized bismuth nanotubes. In addition, we predicted the bismuth clusters {Bi(20)(C(5V)), Bi(24)(C(6v)), Bi(28)(C(1)), B(32)(D(3H)), Bi(60)(C(I))} and calculated their conductor properties.

State of the art of the bi- and trimetallic nanoparticles on the basis of gold and iron.

Recently reported patents and experimental articles on the synthesis, properties, and main applications of core-shell nanoparticles, containing iron or its oxides and gold, as well as trimetallic systems on their basis, are reviewed. These nanostructures were obtained by a series of methods, including reduction in reverse micelles, decomposition of organometallic compounds, electron-beam, laser and gamma-irradiation, sonolysis and electrochemical methods. (Fe or Fe(X)O(y))/Au nanoparticles are subject to be functionalized with organic moieties, may expand their main applications, which consist of catalysis, biological and biomedical uses.

N-[3-(2,6-Dimethylanilino)-1-methylbut-2-enylidene]-2,6-dimethylanilinium chloride.

The title salt, C(21)H(27)N(2) (+)·Cl(-) resulted from the condensation between 2,6-dimethyl-aniline and acetyl-acetone in acidified ethanol. The bulky cation is stabilized in a ß-imino-enamine tautomeric form, and presents a W-shaped conformation. The benzene rings are arranged almost parallel, with a dihedral angle of 6.58 (4)° between the mean planes. Both N-H groups in the cation form strong hydrogen bonds with two symmetry-related chloride anions. The resulting supra-molecular structure is a one dimensional polymer running along [001], alternating cations and anions. The π-π inter-action observed in the mol-ecule, characterized by a centroid-centroid separation of 4.298 (4) Å, is thus extended to the chains, with separations of 5.222 (4) Šbetween benzene rings of neighbouring cations in the crystal.

Synthetic techniques and applications of activated nanostructurized metals: highlights up to 2008.

Main methods for current production of metallic nanoparticles in different forms are reviewed. Metal nanoparticles are generally synthesized in form of nanopowders, nanowires, nanoclusters, nanorods, nanobelts, and nanofilms. Bi- and trimetallic clusters and alloys are also of an interest. Examined techniques for obtaining metal nanoparticles include chemical vapor and electrochemical deposition, use of gamma-, X-ray, laser and UV-irradiation, ultrasonic and microwave treatment, electron- and ion-beams, arc discharge, decomposition and reduction of metal salts and complexes, and biosynthesis. A special attention is paid to Rieke and supported metals.

A review for synthesis of nanoflowers.

The data on nanoflower-like nanostructures are generalized for several groups of inorganic compounds (carbon, elemental metals, their alloys and compounds with the elements of V and VI Groups of the Periodic Table), as well as for a few coordination and organic compounds. Their synthetic techniques include oxidation of elemental metals, reduction of metal salts, thermal decomposition of relatively unstable compounds, or electrochemical route. Some current and possible applications of nanoflowers are noted.

Influence of microwave treatment on the dehydration of crystallohydrates of iron, cobalt and nickel flourides.

Dehydration of inorganic crystallohydrates (Fe2F x 7.1H2O, FeF3 x 3.82O, CoF2 x 4H2O, and NiF2 x 4.4H2O) in the conditions of microwave treatment (MWT) is studied. It is shown that in all cases the MWT changes the defectness of crystals, as well as their thermal stability. The dehydration schemes for the compounds above are presented.