E. Chmielewska a,, W. Tylus b, M. Drabik a, J. Majzlan c, J. Kravcak d, C. Williams e, M. Caplovicova f, L. Caplovic g
a Faculty of Natural Sciences, Comenius University, Mlynska dolina, 842 15 Bratislava, Slovakia
b Institute of Inorganic Technology, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
c Friedrich Schiller University, Chemical Geoscience Faculty, Institute of Geosciences, Burgweg 11, 07749 Jena, Germany
d Faculty of Electrotechnics and Informatics, TUKE, Letna 9, 042 00 Kosice, Slovakia
e University of Wolverhampton, School of Applied Sciences, Wulfruna Street, Wolverhampton WV1 1SB, United Kingdom
f STU Centre for Nanodiagnostics, University Science Park Bratislava Centre, Slovak University of Technology, Vazovova 5, 812 43 Bratislava, Slovakia
g Institute of Materials Science, Faculty of Materials Science and Technology, Slovak University of Technology in Bratislava, J. Bottu 25, 917 24 Trnava, Slovakia
Microporous and Mesoporous Materials
journal homepage: www.elsevier.com/ locate/micromeso
Abstract
Biomimetic sol-gel synthesis was used to prepare new FeO(OH) zeolite (clinoptilolite tuff) adsorbent effective for antimony removal. The product was compared with other on the market accessible natural or commercial adsorption materials like granulated ferric hydroxide GEH, powder of zero valent iron (ZVI)- nanofer and the new synthesized oxi(hydr)oxide FeO(OH) and characterized by XRD, XPS, Raman, FT IR, TG, DTA, DTG, TEM and SEM techniques. Based upon the SEM analysis, the oxidized nanofer sample revealed the existence of hematite and goethite and morphology of FeO(OH) dopant confirmed the presence of ferrihydrite, in less extent also magnetite and hematite. Recorded exothermic maxima on
DTA curves for powdered FeO(OH) zeolite at 460 C and for pure component FeO(OH) at 560 C indicated an 100 C shifted exothermic effect, which characterized strong chemical interaction of FeO(OH) with zeolite structure. Based upon the XPS analyses, also the difference between Fe species in the raw and FeO(OH) doped zeolite was found in increasing Si/Al ratio, however only at the surface below app. 5 nm, measured as 3.94 for raw and 5.38 for sample treated with alkalic solution. The plotting of adsorption isotherms in the system studied clearly showed the increasing uptake capacity of the adsorbents towards antimony with the increased S(BET) data (GEH ˃FeO(OH)˃FeO(OH) zeolite˃nanofer).
