Síntese de material zeolítico de valor agregado a partir de fontes alternativas de silício e alumínio

Abstract

SILVA, K.C. Synthesis of value-added zeolitic material from alternative sources of silicon and aluminum. 2019. 91 p. Dissertação (Mestrado em Tecnologia Nuclear) Instituto de Pesquisas Energéticas e Nucleares, São Paulo. Ash samples generated in the combustion of coal and ash from the burning of sugarcane residues were used as a source of silicon and aluminum to synthesize zeolite 4A by IZA and alkaline fusion followed by hydrothermal treatment. The Si/Al molar ratio for zeolite formation was adjusted by the addition of aluminum residue from the tertiary industry as an alternative source of aluminum. The effects of temperature, melting time and hydrothermal reaction time were investigated. The residues and the synthesized products were characterized by different techniques, such as: X-ray fluorescence, X-ray diffraction, cation exchange capacity, among others. The zeolite synthesized from fly ash was used to remove Cd 2+ and Zn 2+ from aqueous solution in a batch system. The adsorption equilibrium data were evaluated using non-linear equations of the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) models. The D-R and Freundlich models were the best fit for the experimental data of Cd 2+ and Zn 2+ , respectively. The maximum adsorption capacity was 78.0 mg.g -1 for Cd 2+ and 35.8 mg.g -1 for Zn 2+ . The results showed that the coal and biomass ashes mixed with aluminium residues can be used as feedstock to obtain 4A zeolite, considered a value-added material with promising adsorption properties.