This work is devoted to study the photocatalytic ability of cotton textiles functionalized with SiO 2-TiO 2 and SiO 2-TiO 2-HY composites to degrade a dye molecule. Coatings were prepared by sol-gel method and calcined at different temperatures in a range of 400-750 C. FTIR confirmed the existence of SiÀ ÀOÀ ÀTi bounds and the band located in the region between 570 and 600 cm À1 was used to calculate the framework Si/Al ratio of HY in the SiO 2-TiO 2-HY composites. XRD confirmed the presence of nanosized TiO 2 (anatase phase) in all calcined composites. Nitrogen adsorption isotherms showed a decrease in surface area and pore volume for higher calcination temperature. A simple mechanical process was used to impregnate the different composites on the cotton substrates. The photocatalytic activity of cotton textiles functionalized with SiO 2-TiO 2 and SiO 2-TiO 2-HY composites was tested via the degradation of Rhodamine B (RhB) dye under similar solar irradiation. The best catalytic performance was achieved with the SiO 2-TiO 2 and SiO 2-TiO 2-HY composites subjected to a calcination treatment at 400 C, whereas SiO 2-TiO 2 presented a decolourization and mineralization around 94% and 89%, respectively, after 2 h of irradiation. Furthermore, the products of RhB degradation were analysed and identified by using HPLC-ESI-MS and ion chromatography techniques and a photocatalytic mechanism was proposed.

No abstract

The electrochemical oxidation of oxalic and oxamic acids on multiwalled carbon nanotubes (CNT) and on monometallic (Pd and Pt) and bimetallic (Pd-Cu, Pt-Cu) catalysts supported on multiwalled carbon nanotubes was investigated using cyclic voltammetry. The electrodes were prepared by dispersion of the catalytic material on Toray carbon (CT) using a Nafion/water solution. The kinetic parameters of the reactions were determined using cyclic voltammetry. Modification of Toray carbon electrode with carbon nanotubes enables the oxidation of oxalic and oxamic acids in the solvent stability region. The highest oxidation current densities were observed for the Pt-Cu/CNT/CT electrode in 0.1 M NaCl. The oxidation potentials for both oxalic and oxamic acids in this case were lower than those observed with the CNT/CT electrode.The prepared electrocatalysts show good mechanical and chemical stability.

The electroreactivity of amoxicillin (AMX) was studied on catalysts based on platinum, palladium and ruthenium supported on carbon nanotubes (Pt/CNT, Pd/CNT, Ru/CNT) in aqueous media using cyclic voltammetry. Cyclic voltammograms show two oxidation processes, the first one between 0.5 and 1.0 V vs. reference hydrogen electrode (RHE) and the second one between 1.2 and 1.6 V vs. RHE. The effects of electrocatalytic material and supporting electrolyte, on current intensities and oxidation potentials, were determined using experimental design strategy (DOE). Kinetic parameters of the oxidation reactions were calculated from the scan rate study. The constant potential electrolysis of AMX was carried out on Ru/CNT catalyst, in 0.1 M NaOH and AMX conversion reached 45 % after 6 h of electrolysis at 2.5 V vs. RHE. The percentages of CO 3 2À , SO 4 2À and NO 3 À among oxidation products were 26, 17and 4 %, respectively. The primary degradation products of AMX determined by HPLC-MS gave some insight about the reaction pathways.[a] M.

No abstract