No abstract

No abstract

No abstract

No abstract

The adsorption of asphaltenes and resins from toluene solutions onto quartz and feldspar and the effect of this process on the properties of the mineral-aqueous sOlution interface have been investigated. Asphaltenes were adsorbed to a greater extent than resins,and the adsorption of mixtures was at least equivalente to the weighted average of the adsorption of both components separately.The electrophoretic mobility of quartz or feldspar was not modified by the adsorption of asphaltenes or resins, indicating that the sites responsible for the surface charge of the minerals were unaffected by the presence of the adsorved organic species. The adsorption turned the minerals partially hydrophobic. This effect is more important for asphaltene covered particles which do not immerse in aqueous electrolyte solutions, indicating a contact angle larger than 90~immersion become spontaneous in liquid mixtures (methanol-water,ethanol-water), presenting a surface tension lower than 35 mNm-I.Ethoxylated and ethoxylated-propoxylated surface active agents prevent the adsorption of asphaltenes and resins on the minerals, and this effect increases as the ethoxylated/ propoxylated moiety of the surfactant increases.

No abstract

This report describes the characterization of a sedimentary occurrence from the Parnaíba Basin, Brazil, containing the zeolite stilbite intertwined with smectitic clay mineral. The head samples from different sites present a wide content range of the zeolitic phase -15% to 50%. The use of simple separation techniques -conventional gravitic treatmentsyields concentrates containing about 67% of the zeolitic component. Assays with the amendments of these concentrates with plant nutrients yield release rates matching those reported for similar commercial products.

Water contaminated by oil poses challenges to the management of water resources. Magnetic nanoparticles has been issue of different potential applications including remotion oil from water. Magnetic polystyrene-palygorskite nanocomposites were prepared by a heterogeneous phase polymerization for the removal of organic contaminants from water. The organo-Fe 3 O 4 -palygorskite nanoparticles were coated with polystyrene, forming water repellent and oil absorbing surfaces to promote the removal of oil from the surfaces of nanocomposites by applying an external magnetic field. X-ray fluorescence, X-ray diffraction, scanning electron microscopy, zeta potential and size distribution measurement, surface area determination by BET, density measurement by He pycnometry, carbon grade determination, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, and evaluation of hydrophobicity by contact angle were used to characterize the nanoparticles. The magnetic nanocomposite obtained showed excellent hydrophobicity, around 788 contact angle. In addition, oil removal capability tests were also performed, according to which the preliminary results indicated removal of approximately 98% of oil in synthetic oily water samples. The oil-water separation using this magnetic nanocomposite provides a promising alternative strategy for water treatment.