Morphological and physicochemical properties of dip-coated poly {(2,5-diyl pyrrole) [4-nitrobenzylidène]} (PPNB) thin films: towards photovoltaic applications

A new material: conjugated poly {(2,5-diyl pyrrole) [4-nitrobenzylidène]}, that we called (PPNB), has been synthesized and characterized. The cyclic voltammetry has been used in order to estimate first oxidation (Ep) and reduction (En) potentials of our polymer. These values have been assigned, respectively, to the position of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and determination of the energy band gap which have been estimated to be 6.16, 3.89 and 2.27 eV respectively. Energy levels values of the HOMO and LUMO of the PPNB polymeric donor material were evaluated and the results are compatible with an electron transfer to C60 within an eventual junction, such values show that PPNB could be probed for applications in organic solar cells as donor material. PPNB Thin films have been deposited by dip-coating technique from Dichloromethane solvent with different polymer concentrations, and a dipping speed of 3.0 cm/min. For morphological characterization of the films scanning electron microscopy (SEM) was carried out. The samples, when observed by SEM, reveals that the films deposited are less dense, uniform. Cross-sectional SEM micrographs PPNB films show that thickness of the layers is homogeneous and has value of 35–40 nm. Optical characteristics of the polymer thin films were studied using UV-vis spectroscopy; absorption of wide range of wavelengths from 350 to 700 nm was observed. The optical band gap energy ranges between 1.9 eV and 1.94 eV. Based on these analyzes we realized heterojunction organic solar cells with the structure: ITO/Au/PPNB/C60/BCP/Al, the cells had a photovoltaique effect after J-V measuring, however the efficiency of photo generation under AM1.5 illumination was weak (about 0.02%) and needs to be improved

EMULSION LIQUID MEMBRANE EXTRACTION OF CERIUM IONS FROM ACIDIC SOLUTION USING CYANEX 301

Membrane processes for separation of chemical species from a mixture are gaining in importance and are emerging as a viable alternative to conventional separation processes. The emulsion liquid membrane (ELM) technique was regarded as an emerging separation technology and was extensively examined for potential applications in such fields as hydrometallurgy, environmental engineering, biochemical engineering, pharmaceutical engineering, and food technology. In the present work, the removal of Cerium ions from acidic solution by using an emulsion liquid membrane (ELM) technique was investigated and we obtained > 98% efficiency with the treatment. For the transport of Ce(III) ions using Cyanex 301 as extractant, the effects of extractant and surfactant concentrations, mixing speed, concentration and type of stripping solution, phase ratio, treatment ratio, and nature of diluent on the extraction rate were studies. Under the optimum conditions, solvent extraction and stripping of Ce(III) ions were investigated

Metal-loaded mesoporous MCM-41 for the catalytic wet peroxide oxidation (CWPO) of acetaminophen

MCM-41 based catalysts (molar ratio Si/Al = 40) were prepared by a hydrothermal route, modified by ionic exchange with different metals (Cu, Cr, Fe and Zn) and finally calcined at 550 °C. The catalysts were fully characterized by different techniques that confirmed the formation of oxides of the different metals on the surfaces of all materials. Low-angle X-ray diffraction (XRD) analyses showed that calcination resulted in the incorporation of metallic Zn, Fe and Cr in the framework of MCM-41, while in the case of Cu, thin layers of CuO were formed on the surface of MCM-41. The solids obtained were tested in the catalytic wet peroxide oxidation (CWPO) of acetaminophen at different temperatures (25–55 °C). The activity followed the order: Cr/MCM-41 ≥ Fe/MCM-41 > Cu/MCM-41 > Zn/MCM-41. The increase of the reaction temperature improved the performance and activity of Cr/MCM-41 and Fe/MCM-41 catalysts, which achieved complete conversion of acetaminophen in short reaction times (15 min in the case of Cr/MCM-41). Fe/MCM-41 and Cr/MCM-41 were submitted to long-term experiments, being the Fe/MCM-41 catalyst the most stable with a very low metal leaching. The leaching results were better than those previously reported in the literature, confirming the high stability of Fe/MCM-41 catalysts synthesized in this study

Preparation of activated carbon-metal nanoparticle composite materials for the catalytic reduction of organic pollutants

This work focuses on the preparation of inexpensive composite materials based on activated carbon-containing metallic nanoparticles MNPs (M = Cu, Ag, Fe). The metal nanoparticles supported on the activated carbon were prepared by ultrasound followed by chemical treatment using a reducing agent NaBH4. The obtained materials were characterized by XRD, XRF, FTIR, XPS, TGA, SEM, and TEM analysis. The different samples were tested as catalysts for the catalytic reduction of organic pollutants (MB, MO, 4-NP) in a simple and binary system in the presence of NaBH4. The results confirmed that the content of metal nanoparticles was in the following sequence 2.12%, 11.15%, and 12.13% for the materials AC-Ag, AC-Cu, and AC-Fe, respectively. According to TEM analysis, the size and dispersion of nanoparticles differ from one catalyst to another, hence the AC-Cu material exhibited good dispersion of CuNPs having ultrafine particles in the range of 4–14 nm. In order to optimize the best conditions for the reduction reaction, the effect of the nature of the catalyst, the initial concentration of NaBH4, the concentration of the pollutant, the mass of the catalyst and the nature of the pollutant were studied, and discussed. In terms of efficiency, the AC-Cu sample was the most efficient catalyst compared to AC-Fe, and AC-Ag, mainly due to the good dispersion of CuNPs on the surface of activated carbon. The recorded rate constant for the MB, MO, and 4-NP in the single system using the same operating conditions was 0.0259 s − 1, 0.0218 s − 1, and 0.0074 s − 1, respectively. In the binary system containing MB + MO or MB + 4-NP, the AC-Cu catalyst was more selective towards the MB dye in both systems. The reuse of the AC-Cu catalyst towards the reduction of the MB dye showed good performance during five consecutive cycles without losing its efficiency