{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,28]],"date-time":"2026-07-28T16:49:40Z","timestamp":1785257380080,"version":"3.55.0"},"reference-count":29,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,2,22]],"date-time":"2021-02-22T00:00:00Z","timestamp":1613952000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004482","name":"Kuwait University","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004482","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Chem."],"abstract":"<jats:p>The test alumina (the so-called \u03b9-Al<jats:sub>2<\/jats:sub>O<jats:sub>3<\/jats:sub>) was thermally recovered at 1,100\u00b0C from chitosan-AlO<jats:sub>x<\/jats:sub> hybrid films and found to contain Na and Ca impurity ions inherited from the parent chitosan. Two different modifications of pure alumina, namely, \u03b3- and \u03b1-Al<jats:sub>2<\/jats:sub>O<jats:sub>3<\/jats:sub>, were adopted as control samples. The test and control aluminas were examined for 1) the bulk elemental constitution by atomic absorption spectroscopy (AAS), 2) the surface chemical composition by X-ray photoelectron spectroscopy (XPS), 3) the bulk phase composition by X-ray powder diffractometry (XRD), <jats:italic>ex-situ<\/jats:italic> Fourier-transform infrared spectroscopy (IR), and Laser Raman (LRa) spectroscopy, 4) the surface area, topography, and morphology by N<jats:sub>2<\/jats:sub> sorptiometry, and atomic force (AFM) and scanning electron microscopy (SEM), 5) the surface adsorptive interactions with pyridine and 2-propanol gas-phase molecules by <jats:italic>in-situ<\/jats:italic> IR spectroscopy of the adsorbed species, and 6) the surface catalytic interactions with 2-propanol gas-phase molecules by <jats:italic>in-situ<\/jats:italic> IR spectroscopy of the gas phase. Results obtained could clearly show that the test alumina (\u03b9-Al<jats:sub>2<\/jats:sub>O<jats:sub>3<\/jats:sub>) is only hypothetically pure alumina since in reality its bulk structure is majored by mullite-type Na-aluminate (Na<jats:sub>0.67<\/jats:sub>Al<jats:sub>6<\/jats:sub>O<jats:sub>9.33<\/jats:sub>\/NaAlO<jats:sub>2<\/jats:sub>) and minored by Na-\u03b2-alumina (Na<jats:sub>1.71<\/jats:sub>Al<jats:sub>11<\/jats:sub>O<jats:sub>17<\/jats:sub>) and \u03b2-alumina (NaAl<jats:sub>11<\/jats:sub>O<jats:sub>17<\/jats:sub>). Consistently, observed Na-influenced modifications of the surface chemistry, topology, and morphology, as well as adsorptive and catalytic interactions with pyridine and 2-propanol gas-phase molecules, showed significant deviations from those exhibited by the control pure aluminas (\u03b3- and \u03b1-Al<jats:sub>2<\/jats:sub>O<jats:sub>3<\/jats:sub>).<\/jats:p>","DOI":"10.3389\/fchem.2021.633877","type":"journal-article","created":{"date-parts":[[2021,2,22]],"date-time":"2021-02-22T05:20:09Z","timestamp":1613971209000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":4,"title":["Na-Influenced Bulk and Surface Properties of the So-Called Iota(\u03b9)-Alumina: Spectroscopy and Microscopy Studies"],"prefix":"10.3389","volume":"9","author":[{"given":"Ali","family":"Bumajdad","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shamsun","family":"Nahar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohamed I.","family":"Zaki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,2,22]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"410","DOI":"10.1007\/s10971-018-4617-y","article-title":"High-temperature stable transition aluminas nanoparticles recovered from sol\u2013gel processed chitosan-AlOx organic\u2013inorganic hybrid films","volume":"86","author":"Al Sagheer","year":"2018","journal-title":"J. Sol. Gel Sci. Technol."},{"key":"B2","doi-asserted-by":"publisher","first-page":"356","DOI":"10.1016\/j.carbpol.2011.02.032","article-title":"Visco-elastic properties of chitosan\u2013titania nano-composites","volume":"85","author":"Al-Sagheer","year":"2011","journal-title":"Carbohydr. Polym."},{"key":"B3","doi-asserted-by":"publisher","first-page":"174123","DOI":"10.1103\/PhysRevB.84.174123","article-title":"Structure and properties of the low-density phase \u03b9-Al2O3 from first principles","volume":"84","author":"Aryal","year":"2011","journal-title":"Phys. Rev. B"},{"key":"B4","first-page":"$195","article-title":"Handbook of X-ray photoelectron spectroscopy","volume-title":"Surface and interface analysis","author":"Briggs","year":"1981"},{"key":"B5","doi-asserted-by":"publisher","first-page":"309","DOI":"10.1021\/ja01269a023","article-title":"Adsorption of gases in multimolecular layers","volume":"60","author":"Brunauer","year":"1938","journal-title":"J. Am. Chem. Soc."},{"key":"B6","doi-asserted-by":"publisher","first-page":"89","DOI":"10.1016\/0390-6035(82)90059-1","article-title":"Infrared spectroscopic identification of species arising from reactive adsorption of carbon oxides on metal oxide surfaces","volume":"7","author":"Busca","year":"1982","journal-title":"Mater. Chem."},{"key":"B7","doi-asserted-by":"publisher","first-page":"224","DOI":"10.1111\/j.1151-2916.1974.tb10864.x","article-title":"Existence of mullite without silica","volume":"57","author":"Duvigneaud","year":"1974","journal-title":"J. Am. Ceram. Soc."},{"key":"B8","doi-asserted-by":"publisher","first-page":"3408","DOI":"10.1111\/j.1551-2916.2008.02551.x","article-title":"Synthesis of \u03b9-Al2O3 from a mixture of aluminum nitrate and carboxymethyl cellulose","volume":"91","author":"Ebadzadeh","year":"2008","journal-title":"J. Am. Ceram. Soc."},{"key":"B9","doi-asserted-by":"publisher","first-page":"1513","DOI":"10.2138\/am-2001-11-1220","article-title":"Crystal structures of Na and K aluminate mullites","volume":"86","author":"Fischer","year":"2001","journal-title":"Am. Mineral."},{"key":"B10","first-page":"983","article-title":"Crystal structure of Al-rich mullite","volume":"79","author":"Fischer","year":"1994","journal-title":"Am. Mineral."},{"key":"B11","doi-asserted-by":"publisher","first-page":"971","DOI":"10.1149\/1.2427192","article-title":"The nature of alumina in quenched cryolite-alumina melts","volume":"106","author":"Foster","year":"1959","journal-title":"J. Electrochem. Soc."},{"key":"B12","volume-title":"Infrared spectra of minerals and related inorganic compounds","author":"Gadsden","year":"1975"},{"key":"B13","doi-asserted-by":"publisher","first-page":"1723","DOI":"10.1039\/F19898501723","article-title":"Infrared spectroscopic studies of the reactions of alcohols over group IVB metal oxide catalysts. Part 1. \u2014Propan-2-ol over TiO2, ZrO2 and HfO2","volume":"85","author":"Hussein","year":"1989","journal-title":"J. Chem. Soc., Faraday Trans. 1: Physical Chemistry in Condensed Phases"},{"key":"B14","article-title":"International center for diffraction data","year":"2005"},{"key":"B15","first-page":"707","volume-title":"Handbook of heterogeneous catalysis","author":"Kn\u00f6zinger","year":"2008"},{"key":"B16","doi-asserted-by":"publisher","first-page":"219","DOI":"10.2478\/s11696-008-0014-2","article-title":"Rapid solidification processing in molten salts chemistry: X-ray analysis of deeply undercooled cryolite-alumina melts","volume":"62","author":"Korenko","year":"2008","journal-title":"Chem. Pap."},{"key":"B17","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1007\/s00706-009-0229-0","article-title":"Rapid solidification of cryolite and cryolite\u2013alumina melts","volume":"141","author":"Kuchar\u00edk","year":"2010","journal-title":"Monatshefte f\u00fcr Chemie\u2014Chemical Monthly"},{"key":"B18","doi-asserted-by":"publisher","first-page":"1567","DOI":"10.3390\/md8051567","article-title":"Application of spectroscopic methods for structural analysis of chitin and chitosan","volume":"8","author":"Kumirska","year":"2010","journal-title":"Mar. Drugs"},{"key":"B19","doi-asserted-by":"publisher","first-page":"4276","DOI":"10.1016\/j.jeurceramsoc.2020.03.038","article-title":"Mullite-type Na0.67Al6O9.33 and a discussion of iota-alumina","volume":"40","author":"Lenz","year":"2020","journal-title":"J. Eur. Ceram. Soc."},{"key":"B20","doi-asserted-by":"publisher","first-page":"1526","DOI":"10.1021\/j100839a044","article-title":"Surface hydroxyl groups on \u03b3-alumina1","volume":"64","author":"Peri","year":"1960","journal-title":"J. Phys. Chem."},{"key":"B21","doi-asserted-by":"publisher","first-page":"405","DOI":"10.1111\/j.1151-2916.1974.tb11423.x","article-title":"Silica-free phases with mullite-type structures","volume":"57","author":"Perrotta","year":"1974","journal-title":"J. Am. Ceram. Soc."},{"key":"B22","first-page":"71","article-title":"A modification of Al2O3 with the sillimanite structure","author":"Saalfeld","year":"1962"},{"key":"B23","doi-asserted-by":"publisher","first-page":"2948","DOI":"10.1111\/jace.13817","article-title":"Mullite: crystal structure and related properties","volume":"98","author":"Schneider","year":"2015","journal-title":"J. Am. Ceram. Soc."},{"key":"B24","first-page":"4","volume-title":"X\u2010ray characterization of materials","author":"Snyder","year":"1999"},{"key":"B25","article-title":"Oxides and hydroxides of aluminum: alcoa","author":"Wefers","year":"1987"},{"key":"B26","doi-asserted-by":"publisher","first-page":"261","DOI":"10.1016\/S0927-7757(01)00690-2","article-title":"In situ FTIR spectra of pyridine adsorbed on SiO2\u2013Al2O3, TiO2, ZrO2 and CeO2: general considerations for the identification of acid sites on surfaces of finely divided metal oxides","volume":"190","author":"Zaki","year":"2001","journal-title":"Colloid. Surface. Physicochem. Eng. Aspect."},{"key":"B27","doi-asserted-by":"publisher","first-page":"430","DOI":"10.1021\/la990739q","article-title":"Surface chemistry of acetone on metal oxides:\u2009 IR observation of acetone adsorption and consequent surface reactions on silica\u2212alumina versus silica and alumina","volume":"16","author":"Zaki","year":"2000","journal-title":"Langmuir"},{"key":"B28","doi-asserted-by":"publisher","first-page":"367","DOI":"10.1016\/0304-5102(90)85010-F","article-title":"Effect of foreign ion additives on ceria surface reactivity towards isopropanol adsorption and decomposition: an infrared investigation","volume":"57","author":"Zaki","year":"1990","journal-title":"J. Mol. Catal."},{"key":"B29","doi-asserted-by":"publisher","first-page":"201","DOI":"10.1016\/0254-0584(87)90056-3","article-title":"Carbon monoxide\u2014a low temperature infrared probe for the characterization of hydroxyl group properties on metal oxide surfaces","volume":"17","author":"Zaki","year":"1987","journal-title":"Mater. Chem. Phys."}],"container-title":["Frontiers in Chemistry"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fchem.2021.633877\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,2,22]],"date-time":"2021-02-22T05:20:15Z","timestamp":1613971215000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fchem.2021.633877\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,2,22]]},"references-count":29,"alternative-id":["10.3389\/fchem.2021.633877"],"URL":"https:\/\/doi.org\/10.3389\/fchem.2021.633877","relation":{},"ISSN":["2296-2646"],"issn-type":[{"value":"2296-2646","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,2,22]]},"article-number":"633877"}}