Síntesis de partículas de óxido de cromo (Cr2O3) a partir de aguas residuales provenientes de la curtiembre Andaluz de la ciudad de Ambato

Abstract

The purpose of this study was to synthesize chromium oxide particles using the wastewater from the Andaluz tannery located in Ambato city. For this purpose, the precipitation method was applied with a total of 27 tests directly with the basic chromium sulfate at concentrations (0,05; 0,1; 0,2)M primary reagent in the tanning industry and different calcination temperatures (400, 600, 700)°C, for the synthesis, ammonium hydroxide NH4OH was used as precipitating agent until reaching a pH of 10, the precipitate was filtered and dried in an oven at 70°C for 24 hours, the dried sample was calcined for 5 hours, then crushed and sieved on a 100 mesh sieve. The material obtained was characterized in an Infrared Spectrophotometer, Scanning Electron Microscope (SEM) followed by EDX analysis and portable X-ray Fluorescence analysis that allowed to determine the ideal conditions to apply them to the wastewater following the same synthesis method. By using SEM, the particle size distribution could be determined and the EDX detector established the chromium oxide content in the different tests. Variables such as CrOHSO4 concentration and calcination temperature were controlled to obtain the perfect condition for synthesis (0,1M and 700°C) that were applied to the wastewater. Through these conditions, the Cr2O3 particles could be synthesized with the wastewater, which was also characterized by an Infrared Spectrophotometer in order to determine the possible compounds in the water, the obtained in the Scanning Electronic Microscope (SEM) was able to determine that the particle size ranges from 0.33 um to 0,51 um followed by an EDX analysis that confirmed the formation of chromium oxide in the material obtained as well as the presence of other oxides that are due to the impurities in the wastewater. With the XRD analysis it was possible to compare the diffraction pattern of the material obtained with that of different previous investigations. The angular angles of diffraction of most of the peaks formed coincide with the diffraction angles of the aforementioned investigation, which verifies the formation of Cr2O3. It is recommended that a Dynamic Light Scattering (DLS) analysis be performed to determine the average particle size with greater accuracy.