A novel synthesis process of ETS-4 titanosilicate using commercial anatase in the absence of fluoride ions

Abstract

A novel synthesis process for ETS-4 titanosilicate using commercial anatase as the titanium source in the absence of fluoride ions was studied. Fluoride ions and traced ETS-4 seeds have important roles in forming ETS-4 structures. However, the method using ETS-4 seeds instead of fluoride ions to improve product purity and productivity is environment-friendly. ETS-4, ETS-4(NS), and ETS-4(NaF) were respectively synthesized using traced ETS-4 seeds, without seeds, and with fluoride ions. The as-synthesized samples were identified by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. Adsorption isotherms and adsorption heats of nitrogen and methane on the prepared ETS-4 were also measured. The results showed that ETS-4 samples could be prepared using anatase in the absence of fluoride ions, with good purity, comparable physicochemical properties, and excellent adsorption properties.

Keywords

titanosilicate / anatase / gas adsorption / microporous materials

References

[1] Nair S., Jeong H.K., Chandrasekaran A., Braunbarth C.M., Tsapatsis M., Kuznicki S.M. Synthesis and structure determination of ETS-4 single crystals. Chem. Mater., 2001, 13, 4247

[2] Ferdov S., Lin Z., Sá Ferreira R.A., Correia M.R. Hydrothermal synthesis, structural, and spectroscopic studies of vanadium substituted ETS-4. Microporous Mesoporous Mater., 2008, 110, 436

[3] Pillai R.S., Peter S.A., Jasra R.V. Adsorption of carbon dioxide, methane, nitrogen, oxygen and argon in NaETS-4. Microporous Mesoporous Mater., 2008, 113, 268

[4] Uguina M.A., Delgado J.A., Águeda V.I., García-Sanz A. Microwave synthesis of Sr-ETS-4 and evaluation of its molecular sieving properties in the nitrogen/methane separation. Stud. Surf. Sci. Catal., 2008, 174, 591

[5] Turta N.A., Veltri M., Vuono D., De Luca P., Bilba N., Nastro A. Effect of crystallization temperature on the synthesis of ETS-4 and ETS-10 titanosilicates. J. Porous Mater., 2009, 16, 527

[6] Serrano D.P., Van Grieken R., Sanchez P., Sanz R., Rodrguez L. Crystallization mechanism of all-silica zeolite beta in flouride medium. Microporous Mesoporous Mater., 2001, 46, 35

[7] Zhang Y.Q., Zhou W., Liu S.X., Navrotsky A. Controllable morphology of Engelhard titanium silicates ETS-4: synthetic, photocatalytic, and calorimetric studies. Chem. Mater., 2011, 23, 1166

[8] Rocha J., Brandao P., Pedrosa de Jesus J.D., Philippoub A., Andersonb M.W. Synthesis and characterization of microporous titanoniobosilicate ETNbS-10. Chem. Commun., 1999, 471–472, 471

[9] Lin Z., Rocha J., Brandão P., Ferreira A., Esculcas A.P., Pedrosa de Jesus J.D., Philippou A., Anderson M.W. Synthesis and structural characterization of microporous umbite, penkvilksite, and other titanosilicates. J. Phys. Chem. B, 1997, 101, 7114

[10] Marathe R.P., Mantri K. Synthesis, characterization and adsorption properties of ETS-4 molecular sieve. J. Metastable Nanocryst. Mater., 2005, 23, 99

[11] Kuznicki S.M., Bell V.A., Nair S., Hillhouse H.W., Jacubinas R.M., Braunbarth C.M., Toby B.H., Tsapatsis M. A titanosilicate molecular sieve with adjustable pores for sizeselective adsorption of molecules. Nature, 2001, 412, 720

[12] Armaroli T., Busca G., Milella F., Bregani F., Toledo G.P., Nastro A., De Luca P., Bagnasco G., Turco M. A study of ETS-4 molecular sieves and their adsorption of water and ammonia. J. Mater. Chem., 2000, 10, 1699

[13] Prasanth K.P., Bajaj H.C., Chung H.D., Choo K.Y., Kim T.H., Jasra R.V. Hydrogen sorption in transition metal modified. J. Alloys Compd., 2009, 480, 580

[14] Delgado J.A., Uguina M.A., Agueda V.I., Garcia-Sanz A. Adsorption and diffusion parameters of methane and nitrogen on microwave-synthesized ETS-4. Langmuir, 2008, 24, 6107