Comparison of conventional and microwave-assisted synthesis and characteristics of aluminum-pillared rectorite

Abstract

The synthesis and characterization of aluminum-pillared rectorite were studied. The synthesis was conducted with both conventional heating and microwave irradiation. Microwave irradiation was found to enhance the intercalation and ion-exchange during synthesis, and to be able to produce the rectorite with a larger d₀₀₁ and a better uniformity. The specific surface area is 180 m²/g and basal spacing is 3.2 nm. The texture change and thermal and hydrothermal stability of cross-linked rectorite were examined using XRD, FTIR, nitrogen-adsorption and TGA. The experimental results show that the aluminum-pillared rectorite, after calcined at 800 °C for 3 hours, can keep the basal aluminum-silicate texture and would not disperse in water at room or an elevated temperature. The aluminum-pillared rectorite shows a high specific surface area, good thermal and hydrothermal stability, and is promising in applications as catalyst carriers and adsorbents for waste treatment.

Keywords

rectorite / pillared-clay / microwave irradiation / catalysis / adsorption

References

[1] Vaccari A. Clays and Catalysis: A Promising Future. Appl. Clay Sci., 1999, 14: 161-198.

[2] Tanabe K, HÖlderich W F. Industrial Application of Solid Acid-base Catalysits. Appl. Catal. A Gen., 1999, 181: 399-434.

[3] Mishra T, Parida K M, Mol J. Transition Metal Pillared Clay: A Para Selective Catalyst for Nitration of Chlorobenzene. Catal. A. Chem., 1997, 121: 91-96.

[4] Shu H T, Li D, Scala A A, Yi H M. Adsorption of Small Organic Pollutants from Aqueous Streams by Aluminosilicatebased Microporous Materials. Separ. Purif. Technol., 1997, 11: 27-36.

[5] Han Y S, Yamanaka S, Choy J H. A New Thermally Stable SiO₂−Cr₂O₃ Sol Pillared Montmorillonite with High Surface Area. Appl. Catal. A Gen., 1998, 174: 83-90.

[6] Gandía L M, Toranzo R, Vicente M A, Gil A. Non-aggressive Pillaring of Clays with Zirconium Acetate. Appl. Catal. A Gen., 1999, 183: 23-33.

[7] Katdare S P, Ramaswamy V, Ramaswamy A V. Ultrasonication: A Competitive Method of Intercalation for the Preparation of Alumina Pillared Montmorillonite Catalysit. Catal. Today, 1999, 49: 313-320.

[8] Long R Q, Yang R T. Selective Catalytic Reduction of NO with Ammonia over V₂O₅ Doped TiO₂ Pillared Clay Catalysts. Appl. Catal. B Environ., 2000, 24: 13-21.

[9] Bahranowski K, Kielski A, Serwicka E M, Wisa-Walsh E, Wodnicka K, Micropor. Influence of Doping with Copper on the Texture of Pillared Montmorillonite Catalysts. Mesopor Minerals, 2000, 41: 201-215.

[10] Brindley G W, Allevardite. A Swelling Double-layer Mica Mineral. Amer. Miner, 1956, 41: 91-10.

[11] Guan J, Min E, Yu Z. Proc. Development of Pillared Clays for Industrial Catalysis.9th Int. Conf. Catal., Calagary, 1988: 443–452

[12] Guan Jingjie, Min Enze, Yu Zhiqing. Class of Pillared Interlayered Clay Molecular Sieve Products with Regularly Interstratified Mineral Structure. U S Pat., 4757040 (1988)

[13] T J Pinnavania, Jingjie G. Stable Supergallery Clay Compositions. U S Pat. 5583082 (1996)

[14] Bagshaw S A, Cooney R P. FTIR Surface Site Analysis of Pillared Clays Using Pyridine Probe Species. Chem. Mater., 1993, 5: 1101-1109.

[15] Bagshaw S A, Cooney R P. Preparation and Characterization of a Highly Stable Pillared Clay: GaAl₁₂-pillared Recterite. Chem. Mater., 1995, 7: 1384-1389.

[16] Fetter G, Heredia G, Velázquez L A, Maubert A M, Bosch P. Synthesis of Aluminum-pillared Montmorillonites Using Highly Concentrated Clay Suspensions. Appl. Catal. A Gen., 1997, 162: 41-45.

[17] Gil A, Vicente M A, Gandía L M. Man Factors Controlling the Texture of Zirconia and Alumina Pillared Clays. Micropor. Mesopor. Mater., 2001, 34: 115-125.

[18] Jiang Tao, Yuanjuri Liu. Rectorite, 1989 Wuhan: Press of Hubei Science and Technology. 70-72.