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Self-assembled semiconducting, paramagnetic polyaniline nanotubes have been synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in aqueous medium in the presence of colloidal silica particles of an average diameter approximately 12 nm, without added acid. The electrical conductivity of polyaniline nanotubes/silica nanocomposites is in the range (3.3-4.0)x10(-3) S cm(-1). The presence of paramagnetic polaronic emeraldine salt form of polyaniline and phenazine units in nanocomposites was proved by FTIR, Raman, and EPR spectroscopies. The influence of the initial silica/aniline weight ratio on the morphology of polyaniline/silica nanocomposites was studied by scanning and transmission electron microscopies. Nanocomposites synthesized by using the initial weight ratio silica/aniline

Self-assembled conducting, paramagnetic polyaniline nanotubes have been synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in aqueous medium in the presence of zeolite HZSM-5, without added acid. The influence of initial zeolite/aniline weight ratio on the conductivity, molecular and supramolecular structure, paramagnetic characteristics, thermal stability, and specific surface area of polyaniline/zeolite composites was studied. The conducting (approximately 10(-2) S cm(-1)), semiconducting (3 x 10(-5) S cm(-1)), and nonconducting (5 x 10(-9) S cm(-1)) composites are produced using the zeolite/aniline weight ratios 1, 5, and 10, respectively. The coexistence of polyaniline nanotubes, which have a typical outer diameter of 70-170 nm and an inner diameter of 5-50 nm, accompanied by nanorods with a diameter of 60-100 nm and polyaniline/zeolite mesoporous aggregates, distinct from the morphology of microporous zeolite HZSM-5, was proved in the conducting nanocomposite by scanning and transmission electron microscopies. FTIR spectroscopy confirmed the presence of polyaniline in the form of conducting emeraldine salt and suggested significant interaction of polyaniline with zeolite. The evolution of molecular and supramolecular structure of polyaniline in the presence of zeolite was discussed.

In vitro release profiles of the drugs from the zeolite-surfactant-drug composites revealed that sustained drug release could be attained over a period of 8 hours. The presented results for drug uptake by surfactant-zeolite composites and the afterward drug release demonstrated the potential use of investigated modified natural zeolite as excipients for advanced excipients in drug formulations.

In this work, a series of iron-containing zeolitic materials has been tested as heterogeneous catalysts for decomposition of H2O2 and for oxidation of the cationic dye Methylene Blue with H2O2 in aqueous solutions. FeAPO and FeBEA zeolites, synthesized through hydrothermal crystallization of basic hydrogels, and FeY and FeZSM-5 zeolites, prepared by ionexchange procedures, have been studied. The ion exchange with Fe(III) cations was performed from different salt solutions. Fe-exchange procedure carried out in Fe-citrate solution has been identified as an attractive option for the preparation of highly effective FeZSM-5 catalysts in wet oxidation processes. It has been shown that both tetrahedral, framework Fe, and octahedral, extra-framework Fe species incorporated into zeolite structure are catalytically active in wet oxidation reactions.

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