title: 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 × 10(6) L m(-2)h(-1) atm(-1)) and CO2 (5.6 × 10(6) L m(-2)h(-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.
authors.affiliation: a Environmental and Nano Science Research Group , Department of Chemistry, University of the Western Cape , Bellville , Cape Town , South Africa.
authors.forename: Alechine E
authors.initials: AE
authors.lastname: Ameh
authors.affiliation: b HySA Infrastructure Centre of Competence, Materials Science and Manufacturing, Council for Scientific and Industrial Research , Pretoria , South Africa.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Musyoka
authors.affiliation: a Environmental and Nano Science Research Group , Department of Chemistry, University of the Western Cape , Bellville , Cape Town , South Africa.
authors.forename: Ojo O
authors.initials: OO
authors.lastname: Fatoba
authors.affiliation: c A.V Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences (TIPS RAS) , Moscow , Russia.
authors.forename: Daria A
authors.initials: DA
authors.lastname: Syrtsova
authors.affiliation: c A.V Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences (TIPS RAS) , Moscow , Russia.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Teplyakov
authors.affiliation: a Environmental and Nano Science Research Group , Department of Chemistry, University of the Western Cape , Bellville , Cape Town , South Africa.
authors.forename: Leslie F
authors.initials: LF
authors.lastname: Petrik
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D000536:Aluminum Hydroxide / Q000737:chemistry*; D060729:Coal Ash / Q000737:chemistry*; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D017670:Sodium Compounds / Q000737:chemistry*; D013019:South Africa; D013499:Surface Properties; D017641:Zeolites / Q000737:chemistry*
chemical_list: D017607:Aluminum Compounds; D060729:Coal Ash; D008567:Membranes, Artificial; D017670:Sodium Compounds; D017641:Zeolites; C539561:sodium aluminate; D000536:Aluminum Hydroxide
keywords: Crystal; fly ash; fused fly ash extract; hydrothermal; multiple stages; permeance; porous; single stage; titanium supports; zeolite NaA membrane