Síntese da Zeólita Silicoaluminofosfato (SAPO-11) empregando resíduo de lâmpadas fluorescentes

Abstract

The fluorescent lamp is material widely used in society. After consumption, inappropriate disposal causes great environmental impacts as it is a material that contains heavy metals, such as mercury. The fluorescent lamp residue (phosphoric powder), after the lamp crushing process, the substances are separated by categories such as: glass, gases, insulation Bakelite and phosphoric powder. This phosphoric powder goes through a distillation process to recover the mercury, leaving the solid residue. In order to use and manage the phosphoric residue, this material was used as an alternative source in the synthesis process of zeolites, which are materials composed by the union of Al and Si tetrahedrons, through the sharing of oxygen atoms. The use of the studied residue, as its chemical composition 9,98% of silicon oxide (source of Si), 8,9% of aluminum oxide (source of Al) and 27,7% of phosphorus oxide (source of P), contributed to the synthesis of a material that has added value, silicoaluminophosphate SAPO-11, AEL structure (Aluminophosphate Eleven), through the hydrothermal process. The studied synthesis parameters were: the additional aluminum source in the synthesis, neutral alumina or aluminum hydroxide, the amount of residue used in the synthesis (2, 1 and 0,5 g) and the crystallization time (185 and 200 ºC), based on the molar composition 1,2DPA:1,0Al2O3:1,0P2O5:0,3SiO2:120H2O. The synthesis results were characterized by X-ray diffraction (XRD), X-ray fluorescence (FRX), fourier transform infrared absorption spectroscopy (FTIR), scanning electron microscopy (SEM) and adsorption analysis and nitrogen desorption. From the results obtained, and under the studied synthesis conditions, the samples 24/SHR0.5, 48/SHR0.5 and 72/SHR0.5, synthesized with the addition of 0.5 g of the residue, at a temperature of 200 ºC in medium static, additional aluminum source aluminum hydroxide and crystallization time of 24 h, 48 h and 72 h, respectively, the best result was obtained, with the formation of the SAPO-11 phases, using the phosphoric residue from the fluorescent lamp. The research carried out in this work is an innovation in the SAPO-11 synthesis process, adding value to the waste and transforming it into a new material, and consequently influencing economically, sustainably and technological innovation.