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Organic–inorganic hybrid materials are synthesized on the base of anhydride-cured epoxyurethane polymer matrix with an ultra-low content of poly(titanium oxide) nanoparticles (0.005 and 0.020 wt.% for TiO2) obtained in situ by the sol–gel method in polyoxypropylene glycol medium. The structure of the formed optically transparent samples was confirmed by the methods of optical microscopy and wide-angle x-ray scattering. As shown, TiO2 reveals itself as an amorphous phase and does not form aggregates of large size (>200 nm). The behaviour of the neat epoxyurethane and of titanium-containing ones is studied under artificially accelerated weathering conditions in a climate chamber. The changes in the properties of films after exposure to UV radiation, elevated temperature and relative humidity are investigated by the methods of IR spectroscopy, hydrostatic weighting, differential scanning calorimetry, thermogravimetric analysis, and spectrophotometry. As found, under the influence of such climatic factors, the chemical structure of the samples changes insignificantly that proves their atmospheric stability. The increase in density and initial temperatures of thermal decomposition as well as the decrease in the increment of heat capacity (ΔCp ) of epoxyurethanes indicate the proceeding of cross-linking reactions via condensation of hydroxyl groups in the conditions of the climate chamber, which lead to the formation of a denser structure. After accelerated weathering test, the optical transmission coefficient of all the samples diminishes slightly, but the loss of transparency decreases with increasing content of poly(titanium oxide) (18.2% for the neat epoxyurethane polymer and 11.6% for the sample with 0.020 wt.% TiO2). In general, modified epoxyurethanes have a higher resistance to degradation compared to the unmodified ones that is an evidence of the exhibiting of the UV-shielding properties of TiO2 and the simultaneous absence of its photocatalytic activity, which, on the contrary, would provoke the destruction of the polymer matrix under UVirradiation. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation is an effective method to alleviate environmental pollution which is caused by organic pollutants. The expanding natural contamination has attracted the overall scientists to deal with the advancement of photocatalyst effectively depends on semiconductor for the treatment of defiled water assets by different natural poisons that are delivered from numerous industries. In this work, the research progress of properties and applications of photocatalytic and antimicrobial activities and understanding of the toxicity mechanisms of different metal oxide nanoparticles are reviewed. The metal oxide nanoparticles are a wide band hole semiconductor that can be eager to create electron opening sets when transmitted with light. Photographs are an actuated electron opening that instigates power hydrogen, oxygen, and debases inorganic/natural/organic mixes to make power. This review aims to examine the wide biological and mechanisms of photocatalytic degradation and antimicrobial applications.

In this modern era, (M/MO-NPs) Metal/metal oxide nanoparticles are utilized in various areas. The growth of nanoparticles is tremendous in our daily activities like beauty products, doses, delivery of drugs, and outfit. They can be set up by numerous strategies, for example, green amalgamation and the ordinary compound blend techniques. Green synthesis incorporates endless increase to deliver M/MO-NPs with requesting properties. In Bioengineering, the "green" combination has increased massive consideration as a trustworthy, dependable, and natural benevolent convention for orchestrating a wide scope of Nanomaterials including M/MO-NPs and bio propelled materials. Be that as it may, the utilization of plant extracts for this intention is profitable over organisms because of usability and less biohazard. Union of metal and MO-NPs by using the extract of plant fluid arrangement have increased consideration toward the green methodology and with no antagonistic impact on nature. The current article intends to survey the advancement made lately on nanoparticle biosynthesis by organisms. These microbial assets incorporate microorganisms, organisms, yeast, green growth, and viruses. This study predominantly centers on the biosynthesis of the most usually examined M/MO-NPs, for example, copper, cadmium, noble metals, platinum, titanium oxide, palladium, zinc oxide, and cadmium sulfide.

Water and air pollutants pose a significant environmental problem worldwide and photocatalysis is one way to address this global issue. Photocatalytic degradation of toxic substances under the influence of visible electromagnetic radiation is widely used for wastewater treatment. The most promising method of pollutant removal is the use of photocatalysts based on titanium (IV) oxide, which are recognized as one of the most effective due to chemical resistance, non-toxicity and low cost. However, their practical application is limited by the rapid recombination of photogenerated charge carriers and the selective absorption of light in the UV region due to the large width of band gap. To solve this scientific and practical problem, it is necessary to modify the surface, for example, through metallic or nonmetallic doping, in order to increase its photocatalytic activity due to additional absorption in the visible range of the spectrum. This review presents an analysis of current research on ways to increase the efficiency of TiO2-based photocatalysts.

We studied mechanochemical modification of low-dispersed SnO2 and high-dispersed SnO(OH)2 powders with specific surface area 6 and 198 m2/g. They are perspective materials for photocatalysis and adsorption. The aims of work were: the study of crystal, porous, and electronic structure of obtained products, evaluation of their photocatalytic activity under visible light in the process of dyes degradation. The mechanochemical treatment of powders carried out in air and water at 300-850 rpm using a planetary ball mill Pulverisette-7 (German, «Fritsch»). We used XRD and DTA-TG analysis, UV-Vis and FTIR spectroscopy, adsorption-desorption of nitrogen for characterization of initial and modified samples. We have established that porous structures of investigated samples of powders are changed under milling. The initial high-dispersed powder is porous and poorly crystalline. Its specific surface area decreases after milling: from 198 m2/g for initial sample to 130 and 187 m2/g for samples milled in air and water at 850 rpm, respectively. On the contrary, low-dispersed powder is almost non-porous and well crystallized. Its specific surface area increases about 2 times, but the degree of crystallinity reduces as a result of milling. In general, milling of both powders in water leads to formation of meso-macroporous structure. The shift of band gap and increase in adsorption of visible light occurs after modification of high-dispersed sample. This may be a result of changes in the phase and chemical composition, the size of the crystallites, the degree of hydroxylation of the surface, as well as the formation of defects in the structure. On the other hand, the narrowing of band gap occurs after mechanochemical treatment of low-dispersed sample. As a result, photocatalytic activity in the process of rhodamine B degradation under the action of visible light for all modified powders significantly increases. Maximal activity showed high-dispersed sample milled in air and water at 850 rpm. The degradation rate constants Kd are 7.3∙10-5 and 6.4∙10-5 s-1, respectively. The results of the measurement of total organic carbon content in solution after degradation indicate that not only the discoloration of the solution occurs, but also the partial mineralization of the rhodamine. Thus, the degree of mineralization is up to 75 %. [ABSTRACT FROM AUTHOR]

We studied the interaction in mixture of low-dispersed crystalline zinc and tin oxides as well as in their coprecipitated X-ray amorphous composition under hydrothermal and thermal treatment. The aims of work were the study of phase composition and porous structure of obtained products as well as evaluation of their photocatalytic activity under visible light. We used XRD and DTA-TG analysis, FTIR and UV-Vis spectroscopy, adsorptiondesorption of nitrogen and photocatalytic degradation for characterization of prepared oxide compositions. Hydrothermal treatment at 200-300 °C does not lead to formation of new crystal phases. On the other hand, zinc stannates are formed under the same conditions from coprecipitated oxides. Stannates possess high specific surface area (166-227 m2/g) and developed and regulated micro-mesoporous structure (total pore volume - 0.13- 0.27 cm3/g). The investigation of Rhodamin B photocatalytic degradation in visible region shows that oxides mixture possesses the higher activity than zinc stannates, although the latter have the higher value of specific surface area. However, accessibility of internal surface of porous stannates for dye molecules is obviously insufficient. The rate constant of photocatalytic degradation of Rhodamine B is 4.6-11.2·10-5 s-1 when modified low-dispersed compositions are used as catalysts. The degree of dye mineralization achieves 57 %. [ABSTRACT FROM AUTHOR]