Síntese, caracterização e investigação do potencial de adsorção do CAMOO4

Abstract

The excellent physical and chemical properties of calcium molybdate (CaMoO4) make it an important material in the electro-optical industry, in addition to presenting high potential for application in various fields of scientific research, since, depending on the synthesis method, and/or variation in parameters, different properties can be obtained by altering the morphology and/or structural characteristics. Thus, the present work aims to synthesize CaMoO4 samples by coprecipitation with different pH adjustments, process them at different times in the microwave-assisted hydrothermal system, structurally and morphologically characterize and study the possibility of this material being applied as an adsorbent. metal ion and still, calcine the samples at 600 °C at different times in order to analyze the influence of these parameters on the synthesized samples. X-ray diffraction confirmed the obtaining of single-phase samples with a tetragonal-type powellite structure with an average crystallite size of 105 nm, calculated by the Scherrer equation, for samples calcined in a conventional oven. Rietveld refinement provided information about the volume, composition, lattice parameters and crystallite size of the synthesized samples. The characterization by SEM-FEG confirmed the obtaining of samples that vary between rods, dumbbells and spheres, for which the mechanism of particle formation begins with the nucleation of CaMoO4 nanoparticles, followed by the process of orientation and aggregation of particles precipitated from the solution, and finally the crystal grows by the Ostwald ripening mechanism. The study of CaMoO4 samples as adsorbents for Cr(III), Cd(II) and Mn(II) ions showed that adsorption is more efficient when the pH of the solution containing adsorbent and adsorbate is greater than 7, and presented a superior performance for the Cd(II) ion. The sample synthesized at pH adjusted to 8 showed slightly higher adsorption than the others. All samples obtained at different processing times showed great adsorption potential. Therefore, this material has high potential to be used in the removal of toxic metals in aqueous media.