Synthesis of Zeolite NaA Membrane from Fused Fly Ash Extract
Abstract
Zeolite-NaA membranes were synthesized from an extract of fused South African fly ash on a porous titanium support by a secondary growth method. The influence of the synthesis molar regime on the formation of zeolite NaA membrane layer was investigated. Two synthesis mixtures were generated by adding either aluminium hydroxide or sodium aluminate to the fused fly ash extract. The feedstock material and the synthesized membranes were characterized by X-diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence spectroscopy (XRF). It was found by XRD and SEM that the cubic crystals of a typical zeolite NaA with a dense intergrown layer was formed on the porous Ti support. The study shows that the source of Al used had an effect on the membrane integrity as sodium aluminate provided the appropriate amount of Na+ to form a coherent membrane of zeolite NaA, whereas aluminium hydroxide did not. Morphological, the single hydrothermal stage seeded support formed an interlocked array of zeolite NaA particles with neighbouring crystals. Also, a robust, continuous and well-intergrown zeolite NaA membrane was formed with neighbouring crystals of zeolite fused to each other after the multiple stage synthesis. The synthesized membrane was permeable to He (6.0 x 106 L m-2h-1 atm-1) and CO2 (5.6 x 106 L m-2h-1 atm-1), which indicate that the layer of the membrane was firmly attached to the porous Ti support. Membrane selectivity was maintained showing membrane integrity with permselectivity of 1.1, showing that a waste feedstock, fly ash, could be utilized for preparing robust zeolite NaA membranes on Ti support.
Recommended Citation
A. E. Ameh et al., "Synthesis of Zeolite NaA Membrane from Fused Fly Ash Extract," Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering, vol. 51, no. 4, pp. 348 - 356, Taylor and Francis Group; Taylor and Francis, Mar 2016.
The definitive version is available at https://doi.org/10.1080/10934529.2015.1109410
Department(s)
Mining Engineering
Keywords and Phrases
Crystal; fly ash; fused fly ash extract; hydrothermal; multiple stages; permeance; porous; single stage; titanium supports; zeolite NaA membrane
International Standard Serial Number (ISSN)
1532-4117; 1093-4529
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 Taylor and Francis Group; Taylor and Francis, All rights reserved.
Publication Date
20 Mar 2016
PubMed ID
26761276
Comments
University of the Western Cape, Grant None