Navegando por Autor "Penha, Fábio G."
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Artigo Flotação da mistura argila-quartzo com surfactantes e estudos de pilarização(Sociedade Brasileira de Química, 2011) Piasson, Janaina; Wittee, Christian; Bertella, Francine; Penha, Fábio G.; Pergher, Sibele Berenice CastellãClay is often employed as a catalyst, but quartz impurities can decrease the catalytic efficiency. Fine particles of clay can be purified by flotation. We examined the cationic surfactant hexadecyltrimethylammonium bromide (HTAB), the anionic sodium dodecyl sulfate (SDS) and the non-ionic TRITON X-100 for separating the quartz impurities from clay. Using X-ray diffraction, the separation was monitored for changes in the peaks corresponding to clay and quartz. Cationic surfactant HTAB was most effective in separating the quartz-clay mixture and the selectivity can be explained by internal adsorption of the surfactant onto the clay and external adsorption onto the quartz.Artigo Incorporação de dióxido de titânio em zeólitas para emprego em fotocatálise heterogênea(Sociedade Brasileira de Química, 2010) Merg, Jean C.; Rossett, Franciele; Penha, Fábio G.; Pergher, Sibele Berenice Castellã; Petkowicz, Diego I.; Santos, João H. Z. dosThis work proposes the study of heterogeneous photocatalysis using TiO2 impregnated in zeolites beta, ZSM-5, mordenite, NaXb, NaXp and NaY for the decomposition of methylene blue. The catalysts were characterized by XRD, IR, textural analyses by N2 adsorption, SEM, DRS and the reaction of decomposition was monitored by UV visible. The results indicated that didn't have structural changes in the catalysts after Ti impregnations, only in the case of NaY and NaX zeolites. The better photocatalyst to metylene blue decomposition was beta/Ti zeolite due had one structure more accessible (with bigger porous) helping in TiO2 dispersion and catalytic activeArtigo Síntese e caracterização de argilas organofílicas contendo diferentes teores do surfactante catiônico brometo de hexadeciltrimetilamônio(Sociedade Brasileira de Química, 2011) Lopes, Christian Wittee; Penha, Fábio G.; Braga, Renata Martins; Melo, Dulce Maria de Araújo; Pergher, Sibele Berenice CastellãThe major applications of organoclays are in adsorption of organic polluents. The objective of this work was the synthesis and characterization of organoclays using differents amounts of cationic surfactant hexadecyltrimethylammonium bromide. The clays were characterized by low angle x-ray diffraction (XRD), scanning electron microscope (SEM), infrared with Fourier tranformation (FTIR), BET surface area, elemental analysis (CHN), Foster swell and adsorption of methylene blue. The surfactant can adsorb in differents forms in the interlamelar region changed the basal spacing. The presence of the surfactant adsorbed can be favorable or not in adsorption of the methylene blue due the different interactions dye-organoclays.