Estudio de pirolisis catalítica de residuos plásticos, en termo balanza, sobre zeolitas HZSM-5.

Abstract

In the present investigation, the pyrolysis of polypropylene (PP) and polystyrene (PS) plastic waste was studied in the presence of HZSM-5 zeolitic catalysts synthesized with Si / Al molar ratios of 63, 60 and 57, and at concentrations of 2, 5 and 10% by mass with respect to the polymer, using an open oven with a maximum temperature of 500 ° C. The monitoring of the pyrolysis was performed by infrared spectroscopy using the attenuated total reflection sampling technique (FTIR-ATR), from which the best molar ratio of zeolite and best percentage of catalyst was chosen. The data was crossed with the thermogravimetric reports in a thermobalance in Nitrogen atmosphere at a heating rate of 10 ° C / min. The characterization studies of the synthesized zeolites allowed to establish that the phase that composes the materials is of type HZSM-5 with amorphous structure according to X-ray diffraction of polycrystalline samples and a surface area greater than 600m2 / g, with desorption curves and absorption of type IV nitrogen, which makes the material a good catalyst. The catalysis process allowed to establish that the zeolite with the Si / Al molar ratio of 63, in a percentage of 5% by mass for the polypropylene promotes the decomposition of the polymer 101 ° C below what occurs without the presence of the catalyst, and for the polystyrene Si / Al molar ratio of 60, in percentage of 2% by mass, without reduction of temperature, the decomposition path promoted by the catalyst, is based on the depolymerization and the respective presence of carbonyls in the monomeric chains.