The adsorption behavior of polyvinyl alcohol (PVA) on the CaCO 3 /solution interface under the influence of sodium oleate (SOl) interaction was investigated by the adsorbed amount, FTIR spectra, X-Ray diffraction and zeta potential. Effects of solid to liquid ratio and temperature was also examined. Observed increase of the PVA adsorption in presence of the sodium oleate resulted from a polymer-surfactant complex formation. The surfactant also influences on the structure of the adsorbed polymer layers. This effect was proved by adsorption measurements that allow calculation of the thickness of the adsorbed layer of the polymer on the surface of CaCO 3 in the presence and the absence of sodium oleate. The interaction between oleate anions and PVA is a physical type (via hydrogen bonding).
Conducting polymeric composites have attracted great attention over the last years because of their potential uses in chemical, electronic and optical devices, and as catalysts as well as in adsorption processes. Chemical synthesis of polyaniline (PANI) and polyaniline-SiO2 composite and their adsorptive performance were reported in the present work. These materials were prepared and evaluated for their methylene blue (MB) dye adsorption characteristics from aqueous solution. Adsorption equilibrium kinetic and thermodynamic experiments of MB onto PANI and PANI/SiO2 were studied. The effects of initial dye concentration, contact time and temperature on the adsorption capacity of PANI/SiO2 for MB have been investigated. The pseudo-first order and pseudo-second order kinetic models were used to describe the kinetic data. It was found that adsorption kinetics followed the pseudo-second order at all of the studied temperatures. The Langmuir, Freundlich and Dubinin Raduschkevich adsorption models were used for the mathematical description and the HyperChem v8 software was exploited to propose a possible mechanism of the adsorption process.
The semiempirical AM1 SCF method is used to study the first static hyperpolarizabilities β of some novel mono-O-Hydroxy bidentate Schiff base in which electron donating (D) and electron accepting (A) groups were introduced on either side of the Schiff base ring system. Geometries of all molecules were optimized at the semiempirical AM1. The first static hyperpolarizabilities of these molecules were calculated using Hyperchem package. To understand this phenomenon in the context of molecular orbital picture, we examined the molecular HOMO and molecular LUMO generated via Hyperchem. The study reveals that the mono-O-Hydroxy bidentate Schiff bases have large β values and hence in general may have potential applications in the development of nonlinear optical materials.
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