Obtaining High Temperature Stable Sepiolite via Optimization of Acid Treatment Conditions

Yıl 2023, Cilt: 27 Sayı: 6, 1243 - 1254, 18.12.2023

İlknur Kara

https://doi.org/10.16984/saufenbilder.1310298

Öz

Acid treatment of sepiolite under different molarity of HCl at various times was studied to find the best acid treatment conditions for obtaining anhydrous sepiolite without structural folding and with fully open and empty channels. It was found that high molarity (e.g., 3 M) acid treatment causes severe acid attack and heterogeneous magnesium dissolution from sepiolite particles. In contrast, the low molarity (e.g., 0.5 M) acid treatment dissolves magnesium homogeneously through the particles. This, in turn, affects the behavior of sepiolite upon calcination at 450ºC in that homogeneous magnesium dissolution gives better structural stability and consequently higher amount of open channels with the least amount of magnesium removal (25%). This is verified by rehydration behavior and specific surface area measurements after the calcination, where over 90% of the surface area could be preserved after the calcination of the low molarity acid-treated samples. No change in the morphology of sepiolite fibers was observed after acid treatment.

Anahtar Kelimeler

Sepiolite, Acid treatment, Structural stability, Rehydration, Open channel

Kaynakça

• [1] A. Esteban-Cubillo, R. Pina-Zapardiel, J. S. Moya, M. F. Barba, C. Pecharromán, “The role of magnesium on the stability of crystalline sepiolite structure,” Journal of the European Ceramic Society, vol. 28, no. 9, pp. 1763–1768, 2008.
• [2] K. Brauner, A. Preisinger, “Struktur und Entstehung des Sepioliths,” Tschermaks mineralogische und petrographische Mitteilungen, vol. 6, no. 1, pp. 120–140, 1956.
• [3] S. Balci, “Effect of heating and acid pre-treatment on pore size distribution of sepiolite,” Clay Minerals, vol. 34, no. 4, pp. 647–655, 1999.
• [4] H. Cetisli, T. Gedikbey, “Dissolution kinetics of sepiolite from Eskisehir (Turkey) in hydrochloric and nitric acids,” Clay Minerals, vol. 25, no. 2, pp. 207–215, 1990.
• [5] T. Hibino, A. Tsunashima, A. Yamazaki, R. Otsuka, “Model Calculation of Sepiolite Surface Areas,” Clays and Clay Minerals, vol. 43, no. 4, pp. 391–396, 1995.
• [6] Ö. Demirbaş, M. Alkan, M. Doğan, Y. Turhan, H. Namli, P. Turan, “Electrokinetic and adsorption properties of sepiolite modified by 3- aminopropyltriethoxysilane,” Journal of Hazardous Materials, vol. 149, no. 3, pp. 650–656, 2007.
• [7] H. Nagata, S. Shimoda, T. Sudo, “On Dehydration of Bound Water of Sepiolite,” Clays and Clay Minerals, vol. 22, no. 3, pp. 285–291, 1974.
• [8] C. Serna, J. L. Ahlrichs, J. M. Serratosa, “Sepiolite Anhydride and Crystal Folding,” Clays and Clay Minerals, vol. 23, no. 5, pp. 411–412, 1975.
• [9] M. A. Aramendía, V. Borau, J. Corredor, “Characterization of the Structure and Catalytic Activity of Pt/Sepiolite Catalysts,” Journal of Colloid and Interface Science, vol. 227, no. 2, pp. 469–475, 2000.
• [10] J. A. Cecilia, L. Pardo, M. Pozo, E. Bellido, F. Franco, “Microwave-assisted acid activation of clays composed of 2:1 clay minerals: A comparative study,” Minerals, vol. 8, no. 9, 2018.
• [11] F. Franco, M. Pozo, J. A. Cecilia, M. Benítez-Guerrero, E. Pozo, J. A. Martín Rubí, “Microwave-assisted acid treatment of sepiolite: The role of composition and ‘crystallinity,’” Applied Clay Science, vol. 102, pp. 15–27, 2014.
• [12] G. Rytwo, S. Nir, L. Margulies, “Adsorption of Monovalent Organic Cations on Sepiolite: Experimental Results and Model Calculations,” Clays and Clay Minerals, vol. 46, no. 3, pp. 340–348, 1998.
• [13] A. G. Espantaleón, J. A. Nieto, M. Fernández, A. Marsal, “Use of activated clays in the removal of dyes and surfactants from tannery waste waters,” Applied Clay Science, vol. 24, no. 1, pp. 105–110, 2003.
• [14] M. Marosz, A. Kowalczyk, B. Gil, L. Chmielarz, “Acid-treated Clay Minerals as Catalysts for Dehydration of Methanol and Ethanol,” Clays and Clay Minereals, vol. 68, no. 1, pp. 23– 37, 2020.
• [15] K. Shimizu, R. Maruyama, S. Komai, T. Kodama, Y. Kitayama, “Pd– sepiolite catalyst for Suzuki coupling reaction in water: Structural and catalytic investigations,” Journal of Catalysis, vol. 227, no. 1, pp. 202–209, 2004.
• [16] N. Güngör, S. Işçi, E. Günister, W. Miśta, H. Teterycz, R. Klimkiewicz, “Characterization of sepiolite as a support of silver catalyst in soot combustion,” Applied Clay Science, vol. 32, no. 3, pp. 291–296, 2006.
• [17] Q. K. Wang, T. Matsuura, C. Feng, “The sepiolite membrane for ultrafiltration,” Journal of Membrane Science, vol. 184, no. 2, pp. 153–163, 2001.
• [18] E. Ruiz-Hitzky, “Molecular access to intracrystalline tunnels of sepiolite,” Journal of Materials Chemistry, vol. 11, no. 1, pp. 86–91, 2001.
• [19] L. Bokobza, “Elastomer Nanocomposites: Effect of Filler– Matrix and Filler–Filler Interactions,” Polymers, 15(13), 2900, 2023.
• [20] A. Ruiz, C. Ruiz-Garcia, E. RuizHitzky, “From old to new inorganic materials for advanced applications: The paradigmatic example of the sepiolite clay mineral” Applied Clay Science, vol. 235, 106874, 2023.
• [21] W. Kuang, G. A. Facey, C. Detellier, B. Casal, J. M. Serratosa, E. RuizHitzky, “Nanostructured Hybrid Materials Formed by Sequestration of Pyridine Molecules in the Tunnels of Sepiolite,” Chemistry of Materials, vol. 15, no. 26, pp. 4956–4967, 2003.
• [22] J. L. Valentín, M. A. LópezManchado, A. Rodríguez, P. Posadas, L. Ibarra, “Novel anhydrous unfolded structure by heating of acid pre-treated sepiolite,” Applied Clay Science, vol. 36, no. 4, pp. 245–255, 2007.
• [23] M. Özdemir, I. Kipçak, “Dissolution kinetics of sepiolite in hydrochloric acid and nitric acid,” Clays and Clay Minerals, vol. 52, no. 6, pp. 714–720, 2004.
• [24] N. Abdul-Latif, C. E. Weaver, “Kinetics of Acid-Dissolution of Palygorskite (Attapulgite) and Sepiolite,” Clays and Clay Minerals, vol. 17, no. 3, pp. 169–178, 1969.