Síntese de nanopartículas de fosfetos de metais de transição dispersas em carvões ativados e aplicação em processos Fenton

Abstract

Nanostructured materials based on transition metal phosphides have several interesting physical and chemical properties. Among them, we can mention the magnetic properties of this class of materials and their applications in heterogeneous catalysis. This work aims the synthesis of iron, nickel and cobalt phosphide nanoparticles through a wet-chemistry method (coprecipitation), supported on porous carbon materials derived from the chemical activation of a lignocellulosic percussor endocarp of babassu coconut –, with emphasis on chemical, physical and textural transformations caused by thermal treatments at high temperature, and the application of the carbon materials containing the iron phosphide nanoparticles in advanced oxidative processes to remove industrial dyes via Fenton reaction. X-ray diffraction and scanning electron microscopy combined with energy dispersive X-ray spectrometry experiments showed that the several synthesized materials (at room temperature) are composed of transition metal (Fe, Ni or Co) and P compounds, in different stoichiometric proportions. The thermal treatment of the samples at 1000 °C led to the formation of different crystalline phases of the corresponding metallic phosphides. The N2 physisorption experiments showed different textural characteristics for the thermally treated samples, which exhibited a porous structure composed of distributions of micro and mesopores. The degradation tests via Fenton like reaction were carried out with the samples containing iron phosphide nanoparticles for degradation/removal of the industrial dyes methylene blue, eriochrome black T and Ponceau S. A high degree of degradation was observed for all dyes, ranging from 95 to 99%. These results demonstrate the efficiency of the degradation of dyes and other organic compounds through the use of advanced oxidative processes via Fenton reaction using activated carbon materials containing iron phosphide nanoparticles.