Colloidal synthesis of iron titanate-based nanocomposites exploiting the interaction of solutions of binary oxide nanoparticles, Fe2O3 and TiO2, was investigated with respect to the pH of the reaction medium and the conditions used for the synthesis of the reactants. It has been demonstrated that while the phase composition of the products is rather analogous, involving the formation of iron titanate phases on the grain boundaries of the binary oxide particles, the morphology of the resulting aggregates can be a matter of pH control. The self-assembly mechanisms are guided by the surface charge of the particles, offering nanorod regular colloid crystal structures of altering particles with opposite initial charges at neutral pH and globular aggregates with random distribution of uniformly charged particles at low pH as revealed by DLS and high-resolution TEM studies. The produced materials demonstrated enhanced photocatalytic activity compared to the iron titanates produced by conventional techniques. Magnetic characteristics have also been investigated disclosing the possibility of magnetic separation for the Fe2TiO5 material, making it an attractive candidate for application in the sustainable remediation of wastewaters.

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Two new bacterial strains, Pseudomonas marginales MA32 and Pseudomonas putida MA113, containing nitrile hydratases resistant to cyanide were isolated from soil samples by an enrichment procedure. In contrast to known nitrile hydratases, which rapidly lose activity at low to moderate cyanide concentrations, the enzymes described in this paper tolerate up to 50 mM cyanide. They show a broad substrate spectrum including not only small substrates like acrylonitrile but also nitriles with longer side chains and even nitriles with quarternary alpha‐carbon atoms. Both characteristics are essential for the transformation of ketone cyanohydrins, which are much more instable and therefore releasing much higher amounts of prussic acid than cyanohydrins formed from aldehydes. P. marginales MA32 was used as a whole cell biocatalyst for the hydration of acetone cyanohydrin to α‐Hydroxyisobutyramide, which is a precursor of methacrylamide, an important pre‐polymer. After optimization of the process conditions a maximum amide concentration of more than 1.6 M could be reached within 5 hours with 5 g/L biocatalyst referred to cell dry weight.

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Titanium dioxide nanoparticles, obtained using the sol-gel method and modified with organic solvents, such as acetone, acetonitrile, benzene, diethyl ether, dimethyl sulfoxide, toluene, and chloroform, were used as the filler of polydimethylsiloxane-based electrorheological fluids. The effect of electric field strength on the shear stress and yield stress of electrorheological fluids was investigated, as well as the spectra of their dielectric relaxation in the frequency range from 25 to 10 Hz. Modification of titanium dioxide by polar molecules was found to enhance the electrorheological effect, as compared with unmodified TiO, in accordance with the widely accepted concept of polar molecule dominated electrorheological effect (PM-ER). The most unexpected result of this study was an increase in the electrorheological effect during the application of nonpolar solvents with zero or near-zero dipole moments as the modifiers. It is suggested that nonpolar solvents, besides providing additional polarization effects at the filler particles interface, alter the internal pressure in the gaps between the particles. As a result, the filler particles are attracted to one another, leading to an increase in their aggregation and the formation of a network of bonds between the particles through liquid bridge contacts. Such changes in the electrorheological fluid structure result in a significant increase in the mechanical strength of the structures that arise when an electric field is applied, and an increase in the observed electrorheological effect in comparison with the unmodified titanium dioxide.

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