Hostname: page-component-76fb5796d-9pm4c Total loading time: 0 Render date: 2024-04-28T17:13:06.882Z Has data issue: false hasContentIssue false
  • English
  • Français

The effect of oxalic acid activation on the bleaching properties of a bentonite from Milos Island, Greece

Published online by Cambridge University Press:  27 February 2018

M. Taxiarchou  and
I. Douni
M. Taxiarchou*
Affiliation:
Laboratory of Metallurgy, Department of Mining and Metallurgical Engineering, National Technical University of Athens, Greece, and 9, Iroon Polytechniou Street, GR-157 80 Zografos, Athens, Greece
I. Douni
Affiliation:
Laboratory of Metallurgy, Department of Mining and Metallurgical Engineering, National Technical University of Athens, Greece, and 9, Iroon Polytechniou Street, GR-157 80 Zografos, Athens, Greece
*
*E-mail: taxiarh@metal.ntua.gr
Get access Rights & Permissions [Opens in a new window]

Abstract

A bentonite from Milos, Greece, was activated with oxalic acid and the effect of acid activation conditions on bleaching of sunflower oil was investigated. The activation parameters studied were temperature, retention time and oxalic acid to bentonite mass ratio. The activated materials produced had good bleaching properties and were suitable for industrial use as bleaching earths. Optimum bleaching properties could be achieved using a variety of combinations of acid to bentonite ratios and activation times. Bleaching efficiency tests indicated that 24 h activation at 100°C with 1m oxalic acid and 25% pulp density (w/v) gave results equivalent to that of a commercial bleaching earth (Tonsil Optimum 210 FF). The combination that is likely to be more preferable on an industrial scale was 100°C, 25% pulp density (w/v), 1m initial oxalic acid concentration, 60% recycling of the oxalate solution (making up an acid to bentonite ratio 0.2 w/w) and 6 h activation time. The materials produced under these conditions have acceptable bleaching properties, corresponding to bleaching capacity greater than 78% compared to commercial Tonsil, and colour index (in red and yellow units) equal or even better than Tonsil.

Keywords

acid activationGreek bentonitemontmorillonitebleaching capacitymetals dissolutionsurface area
Type
Research Article
Information
Clay Minerals , Volume 49 , Issue 4 , September 2014 , pp. 541 - 549
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2014

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ajemba, R.O. (2013) Alteration of bentonite from Ughelli by nitric acid activation: kinetics and physicochemical properties. Indian Journal of Science and Technology, 6, 102–109.Google Scholar
Bonney, C.F. (1994) Removal of iron from kaolin and quartz: dissolution in organic acids. Pp. 313–324 in Hyrometallurgy 94. Cambridge. Institution of Mining and Metallurgy, Chapman and Hall.Google Scholar
Chapman, H.D. (1965) Cation-exchange capacity. Pp. 891–901 in: Methods of Soil Analysis – Chemical and Microbiological Properties (C.A. Black, editor), Agronomy 9. American Society of Agronony, Madison, Wisconsin, USA.Google Scholar
Chin, P.F. & Mills, G.L. (1991) Kinetics and mechanisms of kaolinite dissolution: effects of organic ligands. Chemical Geology, 90, 307–317.Google Scholar
Christidis, G.E., Scott, P.W. & Dunham, A.C. (1997) Acid activation and bleaching capacity of bentonites from the islands of Milos and Chios, Aegean, Greece. Applied Clay Science, 12, 329–347.CrossRefGoogle Scholar
Clarke, G.M. (1985) Special clays. Industrial Minerals, 216, 25–34.Google Scholar
Didi, M.A., Makhoukhi, B., Azzouz, A. & Villemin, D. (2009) Colza oil bleaching through optimized acid activation of bentonite. A comparative study. Applied Clay Science, 42, 336–334.Google Scholar
Eisenhour, D. & Reisch, F. (2006) Bentonite. Pp. 357–368 in: Industrial Minerals & Rocks (J.E. Kogel, N.C. Trivedi, J.M. Barker & S.T. Krukowski, editors), Society for Mining & Exploration.Google Scholar
Falaras, P., Kovanis, I., Lezou, F. & Seiragakis, G. (1999) Cottonseed oil bleaching by acid-activated montmorillonite. Clay Minerals, 34, 221–232.CrossRefGoogle Scholar
Gates, W., Anderson, J.S., Raven, M.D. & Churchman, G.J. (2002) Mineralogy of a bentonite from Miles, Queensland, Australia, and characterisation of its acid activation products. Applied Clay Science, 20, 189–197.CrossRefGoogle Scholar
Gonzalez-Pradas, E., Villafranca-Sanchez, M. & Gallego-Campo, A. (1993) Influence of the physical-chemistry properties of an acid-activated bentonite on the bleaching of olive oil. Journal of Chemical Technology and Biotechnology, 57, 213–216.Google Scholar
Grim, R.E. (1968) Clay Mineralogy. McGraw-Hill, New York.Google Scholar
Grim, R.E. & Guven, N. (1978) Bentonites. Geology, Mineralogy, Properties and Uses, Development in Sedimentology, 24. Elsevier, Amsterdam.Google Scholar
Komadel, P., Bujdak, J., Madejova, J., Sucha, V. & Elsass, F. (1996) Effect of non-swelling layers on the dissolution of reduced-charged montmorillonite in hydrochloric acid. Clay Minerals, 31, 333–345.Google Scholar
Komadel, P. & Madejova, J. (2006) Acid activation of clay minerals. Pp. 263–287 in: Handbook of Clay Science (F. Bergaya, B.K.G. Theng & G. Lagaly, editors) Developments in Clay Science, 1. Elsevier Ltd., Amsterdam.Google Scholar
Noyan, H., Onal, M. & Sarikaya, Y. (2007) The effect of sulphuric acid activation on the crystallinity, surface area, porosity, surface acidity and bleaching power of a bentonite. Food Chemistry, 105, 156–163.Google Scholar
Onal, M. & Sarikaya, Y. (2007) Preparation and characterisation of acid-activated bentonite powders. Powder Technology, 172, 14–18.Google Scholar
Permien, T. & Lagaly, G. (1994) The rheological and colloidal properties of bentonite dispersions in the presence of organic compounds. IV. Sodium montmorillonite and acids. Applied Clay Science, 9, 251–263.Google Scholar
Pradas, E.G., Sanchez, M.V., Davies, M.E. & Whittle, M.E. (1993) Preparation of alumina-pillared acid activated clays and their use as chlorophyll adsorbents, Journal of Materials Chemistry, 3, 381–387.Google Scholar
Srasra, E., Bergaya, F., Van Damme, H. & Arquib, N.K. (1989) Bleaching properties of an activated bentonite. Decolourisation of rape-seed oil. Applied Clay Science, 5, 411–421.Google Scholar
Tarasova, I.I., Dudeney, A.W.L. & Pilutzu, S. (2001) Glass sand processing by oxalic acid leaching and photocatalytic effluent treatment. Minerals Engineering, 14, 639–646.Google Scholar
Taxiarchou, M., Panias, D., Douni, I., Paspaliaris, I. & Kontopoulos, A. (1997) Removal of iron from silica sand by leaching with oxalic acid. Hydrometallurgy, 46, 215–227.Google Scholar
Tonsil – Highly active bleaching earths. Sud Chemie S.A. pp.17.Google Scholar
US Patent US 5,008,226 (1991) Process for making acid activated bleaching earth using high susceptibility source clay and novel bleaching earth product.Google Scholar
Veglio, F., Passariello, B. & Abbruzzese, C. (1999) Iron removal process for high-purity silica sand production by oxalic acid leaching. Industrial and Engineering Chemistry Research, 38, 4443–4448.Google Scholar
Vicente-Rodriguez, M.A., Suarez, M., Banares-Munos, M.A. & Lopez-Gonzalez, J.D. 1996. Comparative FT-IR study of the removal of octahedral cations and structrural modifications during acid treatment of several silicates. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 52, 1685–1694.CrossRefGoogle Scholar
Welch, S.A. & Ullman, W.J. (1993) The effect of organic acids on plagioclase dissolution rates and stoichiometry. Geochimica et Cosmochimica Acta, 57, 2725–2736.Google Scholar
Zutic, V. & Stumm, W. (1984) Effect of organic acids and fluoride on the dissolution kinetics of hydrous alumina. A model study using the rotating disc electrode. Geochimica et Cosmochimica Acta, 48, 1493–1503.Google Scholar