The sonochemical method is a novel synthesis route that takes advantage of the use of ultrasonic radiation to obtain different nanomaterials with an improvement in the process variables and material characteristics. In this work, two different synthesis routes to obtain a double perovskite structure were compared in detail. The Pechini synthesis method is a widely used and effective way to obtain this kind of structure by the formation of a cross-linked network of metal cations. Alternatively, in sonochemistry, chemical reactions occur with the application of powerful ultrasound radiation. The final characteristics of synthesized powders of La0.9Sr0.1Fe0.9Co0.1O3±δ (LSFC) were analysed thermally, structurally, morphologically and optically, and their transport properties were evaluated to determine their semiconductor character in a solid oxide fuel cell device and in photocatalytic processes. Structural results indicated a well crystallized perovskite structure with a single cubic phase. The cell parameter a (approx. 3.89 Å) and crystal size measurements (11–20 nm) were determined by Rietveld refinement for samples obtained by both synthesis methods. Thescanning electron microscope micrographs showed aggregates with homogeneous morphology and a uniform particle size distribution, with a rough and porous surface. Optical properties were determined by ultraviolet–visible spectrophotometry and photoluminescence, resulting in an Eg of 1.2 and 0.8 eV in samples from Pechini and sonochemistry, respectively.

The synthesis of four amphiphilic organometallic complexes with the general formula RC = M(CO)₅NH(CH₂)₁₅CH₃, where R is a ferrocenyl 2(a-b) or a phenyl 4(a-b) group as a donor moiety and a Fischer carbene of chromium (0) or tungsten (0) as an acceptor group, are reported. These four push-pull systems formed Langmuir (L) monolayers at the air-water interface, which were characterized by isotherms of surface pressure versus molecular area and compression/expansion cycles (hysteresis curves); Brewster angle microscopic images were also obtained. By using the Langmuir–Blodgett (LB) method, molecular monolayers were transferred onto glass substrates forming Z-type multilayers. LB films were characterized through ultraviolet-visible spectroscopy, atomic force microscopy and X-ray diffraction techniques. Results indicated that films obtained from 2b complex [(Ferrocenyl)(hexadecylamine)methylidene] pentacarbonyl tungsten (0) are the most stable and homogeneous; due to their properties, these materials may be incorporated into organic electronic devices.

A Fe₃O₄/HNTs composite was synthesized, characterized by SEM, TEM, XPS, adsorption–desorption N₂, XRD, FTIR, VSM and Zeta potential, and was used for an ibuprofen adsorption and Fenton oxidation study. The response surface methodology (RSM) and Box–Behnken experimental designs were employed. The effects of pH, contact time, ibuprofen concentration, and Fe₃O₄/HNTs dosage on ibuprofen adsorption were evaluated. Additionally, adsorption isotherms and a kinetic study were performed. The effects of pH, H₂O₂ concentration, and Fe₃O₄/HNTs dosage for IBU removal were also studied. The results of ibuprofen adsorption on Fe₃O₄/HNTs indicate that adsorption was favored at acidic pH. The adsorption followed pseudo-second-order kinetics and a Freundlich isotherm. Under mild conditions (pH 7, 298.15 K) with a Fe₃O₄/HNTs dosage of 1.5 g L⁻¹ and 0.5 M H₂O₂, the heterogeneous Fenton-like reaction achieved 99% ibuprofen removal and 60% mineralization. The Fe₃O₄/HNTs catalyst demonstrated high efficiency for aqueous ibuprofen removal under environmentally mild pH and temperature conditions, and it was easily recoverable and reusable.

A Fe3O4/HNTs composite was synthesized, characterized by XRD, FTIR, SEM, and N2 adsorption-desorption, and was used for an ibuprofen adsorption and oxidation study. The response surface methodology (RSM) and Box-Behnken experimental designs were used. The effect of pH, contact time, IBU concentration, and Fe3O4/HNTs dosage on ibuprofen adsorption were evaluated. Additionally, adsorption isotherms and a kinetic study were performed. The effect of pH, H2O2 concentration, and Fe3O4/HNTs dosage for IBU oxidation were also studied. The results of ibuprofen adsorption on Fe3O4/HNTs indicate that adsorption was favored at acidic pH. The adsorption followed pseudo-second-order kinetics and a Freundlich isotherm. A 99.99% IBU oxidation and 99% mineralization were achieved at pH 7, Fe3O4/HNTs dosage of 1.5 g L-1, and 0.5 M H2O2. The Fe3O4/HNTs catalyst prepared in this study was efficient in removing aqueous ibuprofen through heterogeneous Fenton-like reaction.