Optimization of bleaching power by sulphuric acid activation of bentonite

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Bayram H., Ustunisik G., Önal M., Sarlkaya Y.

Clay Minerals, cilt.56, ss.148-155, 2021 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 56
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1180/clm.2021.28
  • Dergi Adı: Clay Minerals
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Aquatic Science & Fisheries Abstracts (ASFA), CAB Abstracts, Chemical Abstracts Core, Communication Abstracts, Compendex, Geobase, INSPEC, Metadex, Civil Engineering Abstracts
  • Sayfa Sayıları: ss.148-155
  • Anahtar Kelimeler: acid activation, bentonite, bleaching, porosity, soybean oil, METHYLENE-BLUE, VEGETABLE-OILS, CLAY-MINERALS, SURFACE-AREA, SEPIOLITE, MONTMORILLONITE, ADSORPTION, CAPACITY, KINETICS, ISLANDS
  • Ankara Üniversitesi Adresli: Evet

Özet

© 2021 Cambridge University Press. All rights reserved.Acid activations were carried out by heating muds prepared using calcium bentonite (CaB), sulphuric acid (H2SO4), and distilled water yielding different bleaching earths (BE). The individual roles of each process variables including mass fraction of H2SO4 (x) in the dried CaB and pure H2SO4 mixture, heating temperature (T), and contact time (t) on the activation were tested. The raw CaB and each BE were examined using X-ray diffraction analyses, chemical analyses, N2-adsorption/desorption, pH-metry, and tintometry. The BEs content in both the aqueous and oily suspensions were set to 2% by mass in order to measure the pH-value and the bleaching power, respectively. The optimum conditions for the activation to obtain a BE having the same bleaching power (BP=0.60) as Tonsil Optimum Bleaching Earth for soybean oil were determined as x=0.35, T=100oC and t=2 h. The BP increased only marginally upon increasing the activation duration from 2 h up to 10 h at a given x and T. After 10 h, we did not observe any considerable change in the bleaching power of the BE. The mass fraction of total structural metal oxide (y), pH-value, specific pore volume (V), specific surface area (S), and mean internal width (D) of the mesopores for the optimized BE are y=0.10, pH=3.0, V= 0.31 cm3g-1, S= 225 m2g-1, and D=7 nm. pH and D values were found to be more important compared to the other parameters used to bleach the alkali refined soybean oil.