Síntese, caracterização e avaliação de catalisadores obtidos a partir de efluente oriundo da confecção de placas de circuito impresso

Abstract

Air pollution, attributed to the emission of gaseous pollutants from burning of fossil fuels, and water pollution, caused by incorrect disposal of industrial and domestic effluents, are two contemporary concerns related to the degradation of environment. With this in view, this work is intended to transform a possible water - polluting agent - effluent from the production of conductive tracks in printed circuit boards - into a catalyst with potential application in the selective catalytic reduction (SCR) of NO by CO. The methodology is based on the recovery of iron and copper from the effluent, through chemical precipitation, for subsequent impregnation of these metals in two distinct catalytic supports, the niobium pentoxide, of representative national production, and Ce0,8Fe0,2O2-δ, of satisfactory catalytic properties. The treatment of the effluent was responsible for an expressive recovery of 99.99% of iron and 95.47% of copper. The precursor solution, used in the impregnation, showed a significant decrease of 99.11% of contaminants in relation to the gross effluent. However, the catalysts obtained, Fe2O3-CuO/Nb2O5 and Fe2O3-CuO/Ce0,8Fe0,2O2-δ, presented a significant final concentration of chlorides, which ultimately impaired the catalytic performance of these materials. The impregnation also led to the reduction of the specific surface area, due to the partial filling of the pores, the increase of the reducibility, attributed to the more reducible character of the supported oxides. Finally, the support Ce0,8Fe0,2O2-δ showed to be more promising for the SCR of NO by CO, because, in relation to Nb2O5, it presents better reducibility, specific area and catalytic performance.