Abstract

BARRERO, Jenny Andrea García et al. Synthesis of zβ from fly ashes, used in controlled release of nitrates. Ciencia en Desarrollo [online]. 2020, vol.11, n.2, pp.153-169.  Epub Mar 25, 2021. ISSN 0121-7488.  https://doi.org/10.19053/01217488.v11.n2.2020.10748.

In this work, zeolite beta (Zβ) was synthesized using fly ash (CV) from coal-fired Power Plant, Termopaipa, at Paipa, Boyacá (Colombia). The silicon and aluminum were extracted from fly ash, which performed by means an acid pretreatment followed by hydrothermal process with NaOH. To obtain the zeolite beta, silicon source and aluminum source of gel mother and crystallization time were varied, keeping a nominal composition, so that 50SiO2: 1Al2O3: 25TEAOH: Na2O: K2O: 17H2O. In the first experiment, the CV provided the aluminum source, while the silicon source was obtained by CV and fumed silica, which were prepared by hydrothermal synthesis, kept at 170 °C for 40 h, which led to obtain ZSM-5 together with a secondary phase of Mordenite. In the second experiment, the CV provided the source of silicon and were necessary the addition of aluminum sulphate octadecahydrate to complete the amount of aluminum source, which were prepared by hydrothermal synthesis, kept at 170 °C for 60 h, which led to a phase of beta zeolite (Zβ) highly pure. The zeolitic phases were characterized using DRX, FTIR, and SEM and by XRF. The zeolites were modified using (3 -aminopropyl) triethoxysilane (APTES) and hexadecyltrimethylammonium bromide (HDTMA-Br). The results show that the zeolite Zβ-APTES with an adsorption capacity of 5 mmol NO3 -/100g have the mayor potential for controlled fertilizer release.

Keywords : Adsorption; beta zeolite; controlled release; fly ash; nitrates.

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