Síntese de espumas de poliestireno impregnadas com nanopartículas de Cu para aplicação catalítica na degradação (oxidação) do corante azul de metileno

Abstract

Nanomaterials have aroused increasing interest in the field of science in recent years, because materials with nanometer scales have properties that are not observed in non-nanometric materials, mainly properties related to surface area. The use of nanometals is quite varied, and they are already used as catalysts, conductors, antibacterials, dyes, etc., and in this range of applications, copper is very prominent, as in addition to having several properties of noble metals, such as gold and silver, its abundance is much larger, making it a low-cost material. The present work presents a proposal for the synthesis of copper nanoparticles, in a polystyrene matrix, using hydrated penta copper sulfate (CuSO 4 .5H 2 O) and copper ethylhexanoate (C 16 H 30 CuO 4 ) as precursor reagents. The idea was to create a nanofoam that has catalytic activity, as a redox agent, which can be used in the chemical degradation of pollutants, through a simple methodology, which consists only of mixing two micellar microemulsions of the w/o type to obtain CuNPs and subsequently impregnating this material in a polymeric matrix through the TIPS process. Nanometals used in support matrices have already shown to have a superior performance, when compared to their direct application in the intended environment, with the additional advantage of not becoming a source of environmental pollution after their use. Another proposal that is also explored concerns the use of polystyrene in the preparation of nanofoam, which could be an alternative for recycling this material, as it also represents a worrying contaminant. In the present work, the characterization techniques used were ultra violet spectroscopy in the visible region (UV-VIS), dynamic light dispersion (DLS) and x-ray diffractometry (XRD), through which the presence of CuNPs in the synthesized colloidal dispersions, catalytic activity in the oxidative degradation of the dye, growth phenomena caused by the flocculation of CuNPs and the absence of copper in its metallic and oxidized phase in the PS/CuNPs foam. Through a detailed analysis of the results obtained, it can be concluded that the objectives pursued in this work were achieved, despite the limitations observed, which reinforces the need for additional studies that will allow for a more practical application, as well as great economic viability of this system in the fields of catalysis.