Liquid purification or separation – Processes – Ion exchange or selective sorption
Patent
1995-10-06
2000-08-29
Cintins, Ivars
Liquid purification or separation
Processes
Ion exchange or selective sorption
210688, B01D 1504, C02F 142
Patent
active
061103780
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to novel silico-titanate compositions of matter, and methods of making and using such compositions.
2. Background Art
Synthesis of molecular sieves and zeolite-type materials are known to the prior art. The crystalline structure of such materials permits cation or anion exchange (or both) as well as water molecule exchange. Further, such materials not only separate molecules of different size, but are capable of segregating molecules of the same size but of different electrical charge.
Among other uses for molecular sieves, or zeolite-type materials, are as "carriers" for certain volatile catalysts, facilitating chemical reactions. The catalysts are trapped and thereby retained in the zeolite molecular structure during the chemical process. Channelized zeolite-type materials resembling tectosilicates, however, are not the only structures that can effect ion exchange. Several phyllosilicates of clay-like materials, for example, montmorillonite (smectite) and vermiculite, readily exchange cations between the tetrahedral layers.
Syntheses of silicon titanate zeolite-type materials is known to the art. U.S. Pat. No. 3,329,481 to Young, entitled Crystalline Titano-Silicate Zeolites, discloses several Group IV-B metallo-silicate zeolites wherein the metal may be a monovalent or bivalent metal, as well as ammonium or hydrogen.
U.S. Pat. No. 4,938,939, to Kuznicki entitled, Preparation of Small-Pored Crystalline Titanium Molecular Sieve Zeolites, discloses a process of producing crystalline titanium zeolite-type compositions having a pore size of 3-5 Angstroms.
U.S. Pat. No. 4,853,202, also to Kuznicki, entitled Large-Pored Crystalline Titanium Molecular Sieve Zeolites, discloses methods of making crystalline titanium molecular sieve compositions having a pore size of about 8 Angstroms.
"The OD Structure of Zorite" Sandomirskii et al., Sov. Phys. Crystallvgr., 24(6), Nov-Dec. 1979, discloses the crystallographic structure of a naturally occurring alkaline titanosilicate found in Siberia.
U.S. Pat. No. 5,015,453 to Chapman entitled Crystalline Group IVA, Metal-Containing Molecular Sieve Compositions, discloses titanium-silicates, phosphates and phosphosilicates which are three-dimensional microporous crystalline structures.
"The Crystal Structure of a New Natural Sodium Titanosilicate," by E. V. Sokolova et al., Sov. Phys. Dokl., 34(7), 583-585, July 1989, describes a naturally occurring material, sitinakite, found in the former Soviet Union having an empirical chemical formula of (Na.sub.2.251 R.sub.0.693 Ca.sub.0.004 Sr.sub.0.062 Ba.sub.0.026 Ce.sub.0.004).sub..SIGMA.3.04 .times.(Ti.sub.3.56 Nb.sub.0.195 Fe.sub.0.014 Zr.sub.0.006).sub..SIGMA.403 Si.sub.1.928 O.sub.13 (O.sub.0.45 H.sub.0.955).sub..SIGMA.1.00 .times.3.7 H.sub.2 O which, as an idealized formula, comprises Na.sub.2 (H.sub.2 O).sub.2 [(Ti.sub.4 O.sub.5 (OH) (SiO.sub.4).sub.2 ]K(H.sub.2 O).sub.1.7. Within this material specimens having higher Nb impurity contents are speculated to have an orthorhombic symmetry.
SUMMARY OF THE INVENTION (DISCLOSURE OP THE INVENTION)
The present invention relates to silico-titanate compositions (TAMs), structures of these compositions, methods of making these compositions, and methods of using these compositions. The silico-titanate compositions of the present invention (hereafter referred to as "TAM" compositions) reside within the range of the general formula and have a mole ratio of: less than 1 and a=1.0.
The TAM composition may further comprise a metal dopant (MD) having the general formula zMD to provide the general empirical formula zMD:ySi:aTi, wherein z is a coefficient having a range of approximately 0.0 to 1.0 and y and a have values as defined above. Useful metal dopants include Group III elements, Group V elements, Group IV elements, Group VIII elements, Group I elements, and compounds thereof, particularly niobium, antimony, vanadium, copper, manganese, iron, phosphorus, tantalum and the like.
The composition may further
REFERENCES:
patent: 4853202 (1989-08-01), Kuznicki
patent: 5298166 (1994-03-01), Bray et al.
Kirth-Othmer, Encyclopedia of Chemical Technology, Third Ed., vol. 15, 1981, pp. 638-669.
Anthony Rayford G.
Dosch, deceased Robert G.
Philip Chackumcheril Varughese
Cintins Ivars
Cox Charles M.
Kimball, Jr. Albert B.
Sandia Corporation
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