ABSTRACT
This study presents the results obtained for the optimization of the mineralization of losartan (LOS) and hydrochlorothiazide (HCTZ) using the photo-Fenton process with a UV-Vis LED. Experimental design optimization employing a Doehlert matrix and a global desirability function enabled simultaneous evaluation of multiple responses, with factor fitting providing the best conditions that maximized the mineralization efficiency: Fe2+ at 10 mg L-1 and H2O2 at 100 mg L-1. High rates of mineralization of LOS and HCTZ were obtained, with dissolved organic carbon (DOC); removal of almost 75% after 90 min was observed for both pharmaceuticals. The kinetic model showed that the mineralization followed two regimes in the first minutes, with a fast progression followed by slower activity. The energy consumption calculated for mineralization of LOS and HCTZ at a concentration of 20 mg L-1 using the UV-Vis LED-assisted photo-Fenton process, at 60 min, was 130 kWh m-3. The desirability function provides a useful tool for finding optimal experimental conditions for the treatment of effluents with different characteristics. The UV-Vis LED was shown to be a good light source in the photo-Fenton process.
Subject(s)
Hydrogen Peroxide , Water Pollutants, Chemical , Hydrochlorothiazide , Iron , Kinetics , Losartan , Oxidation-Reduction , Ultraviolet Rays , Water Pollutants, Chemical/analysisABSTRACT
This study aimed to synthesize Bi2Fe4O9 and apply it to the degradation of tartrazine yellow dye. Bi2Fe4O9 was synthesized using the solid-state reaction and the Pechini method. The materials obtained were characterized using X-ray diffraction (XRD), visible ultraviolet spectroscopy (UV-Vis) and field emission scanning electron microscopy (FEG). The microscopic images revealed a morphological difference between the two materials in which the material obtained by the Pechini method is the most porous and have the largest surface area. The pellet obtained by the Pechini method was seen to have a lower bandgap value when compared with the sample solid state reaction. In the photocatalysis tests, the best performance was also that of the material obtained by the Pechini method, with 99.34% degradation, while the material obtained by solid state reaction showed 85.86% in 120 minutes. The solution degraded with the material obtained by the Pechini method presented 81.66% of mineralization while the solution with the material obtained by solid state reaction showed 60.97% of mineralization. The results confirmed that the material obtained by both syntheses is able to maintain its effectiveness after 10 repetitions of the photocatalytic process, proving to be promising for waste treatment in the industrial field.
Subject(s)
Bismuth/chemistry , Coloring Agents/analysis , Ferric Compounds/chemistry , Tartrazine/analysis , Wastewater/chemistry , Water Pollutants, Chemical/analysis , Water Purification/methods , Catalysis , Ferric Compounds/chemical synthesis , Microscopy, Electron, Scanning , X-Ray DiffractionABSTRACT
The crystal/electronic structure and vibrational properties of the CuxTiSe2 intercalation compounds were studied combining experimental and theoretical techniques. The Cu added into the TiSe2 matrix was characterized as an intercalant atom into van der Waals gaps from Raman spectroscopy analysis. Theoretical and experimental data indicate the Cu-intercalation effect on the crystalline structure as a local disorder affecting [TiSe6] clusters from SeSe layers, which results in a volume expansion. A significant charge transfer from Cu atoms to the host lattice results in a change from Ti4+ to Ti3+ species, narrowing the band-gap and increasing the superconductivity of the material.
