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WO2008119856A1 - Method for obtaining spheres of titanosilicates - Google Patents

Method for obtaining spheres of titanosilicates Download PDF

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Publication number
WO2008119856A1
WO2008119856A1 PCT/ES2008/000193 ES2008000193W WO2008119856A1 WO 2008119856 A1 WO2008119856 A1 WO 2008119856A1 ES 2008000193 W ES2008000193 W ES 2008000193W WO 2008119856 A1 WO2008119856 A1 WO 2008119856A1
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Prior art keywords
spheres
titanosilicate
crystals
solution
tio
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Spanish (es)
French (fr)
Inventor
Joaquín CORONAS CERESUELA
Jesús SANTAMARÍA RAMIRO
Carlos TÉLLEZ ARISO
Víctor SEBASTIÁN CABEZA
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Universidad de Zaragoza
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Universidad de Zaragoza
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/89—Silicates, aluminosilicates or borosilicates of titanium, zirconium or hafnium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J39/00—Cation exchange; Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/08—Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/14—Base exchange silicates, e.g. zeolites
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B37/00—Compounds having molecular sieve properties but not having base-exchange properties
    • C01B37/005—Silicates, i.e. so-called metallosilicalites or metallozeosilites
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C02F2001/425—Treatment of water, waste water, or sewage by ion-exchange using cation exchangers

Definitions

  • the present invention relates to a process for obtaining porous titanosilicate spheres, with a hierarchical structure, by hydrothermal treatment, controlling the temperature, reaction time, agitation of the titanium and silicon precursor agents, and the composition of the solution precursor
  • the invention relates to areas obtainable by said method and the use thereof.
  • the zeolitic materials have crystalline structures that are constituted by channels and cavities with molecular dimensions. These materials are mainly applied in ion exchange, adsorption and catalysis processes.
  • micropores can sometimes undermine their application mainly due to intra-crystalline diffusional limitations. This is the cause of the slow transport of the compounds involved in a certain process through the channels of the largest zeolitic particles (1).
  • the mixture that is sometimes necessary of the zeolites with certain agents can decrease the efficiency of the properties of the resulting product formed as a tablet, monolith, etc. (2).
  • the zeolitic particles of smaller dimensions in which the length of the diffusion paths is reduced, present an inherent problem of loss of load and risk of manipulation, due to the possibility of formation of potentially harmful aerosols for respiratory system, in addition to the intrinsic difficulty that exists when the small zeolitic crystals are separated by filtration as a consequence of their colloidal properties.
  • zeolites with a hierarchical pore architecture that is, they contain micro and mesopores (or also micro and macropores) (3).
  • This type of zeolites can be the solution to the problems mentioned, and therefore hierarchical materials are being synthesized successfully with micro / mesopores, meso / macropores and micro / macropores, where generally the control of the bimodal porosity is achieved through the combination of certain managing agents of the structure for the achievement of the required organization (4).
  • microspheres of silicalite-1 (7) and beta zeolite (8) have been obtained, using for this purpose director agents of macro-structures (macroplantillas as particulate anion exchange resins with millimeter sizes); hollow spheres of silicalite-1 (macrocavities and macropores surrounded by a continuous framework of zeolite) have been synthesized from mesoporous spheres of silica (9) and also hollow capsules of zeolite (silicalite-1) in a non-spherical shape (10); macroporous silicates with zeolitic structures (silicalite-1) synthesized by hydrothermal synthesis, using monodispersed spheres of polystyrene as guiding agents (6); or simply alternating layers of silicalite-1 nanoparticles and oppositely charged macromolecules, which are then adsorbed in micrometric latex
  • Titanosilicates of the type ETS-4 and ETS-10 are materials with similar properties to zeolites (13).
  • Another very attractive microporous titanosilicate for its application possibilities is that based on the mineral umbite, K 2 (Zr 0 8 Tio 2 ) YES 3 ⁇ 9 ⁇ 2 O (14).
  • the mineral umbite can be synthesized with different isomorphic structures: K 2 ZrSi 3 O 9 -H 2 O (15), K 2 TiSi 3 O 9 -H 2 O (16), K 2 SnSi 3 O 9 -H 2 O ( 17) and K 2 ZrGe 3 O 9 -H 2 O (18).
  • Ti-umbite crystals K 2 TiSi 3 O 9 -H 2 O
  • organic agents that direct the structure to produce solid spheres of micrometric dimensions. that combine micropores (those due to Ti-Umbita) with macropores, thereby producing a hierarchical zeolitic structure of a wide technological application compared to the Ti-umbite crystals themselves.
  • Hierarchical zeolitic structure a structure in which pores of different dimensions are combined in an efficient manner, mitigating problems such as those described above.
  • the hierarchical structure obtained in the present invention connects the macropores between the particles that constitute the spheres with the intraparticular micropores, intrinsic to the titanosilicate, in such a way that transport resistance is reduced, in addition to generating a macro set microporous with a size suitable for handling in industrial processes.
  • IUPAC International Union of Pure and Applied Chemistry
  • micropores less than 2 nm
  • mesopores between 2 and 50 nm
  • macropores greater than 50 nm
  • zeolites are all those crystalline, microporous and hydrated aluminosilicates.
  • Zeolitic is also attributed to other materials that, without being aluminosilicates, are microporous and crystalline (such as silicoaluminophosphates, aluminophosphates, titanosiilicates, etc.), and even to others that, without being crystalline, are nanostructured and have mesopores (such as MCM-41, MCM -48, SBA-15, SBA-16, etc.).
  • a process for obtaining porous titanosilicate or titanosilicate isomorphs is provided, by means of the hydrothermal treatment of a solution comprising at least titanium or silicon precursors, said treatment is carried out at a reaction temperature between 180 and 250 0 C in a synthesis time of between 6 and 96 hours, with a stirring rate of the solution between 15 rpm and 60 rpm (revolutions per minute). Through this procedure individual spheres and crystals are obtained.
  • Ti is replaced by an atom of the group comprising, but not limited to V, Zr, Sn or Nb, and / or compounds where Si can be replaced by atoms of, but not limited to to Ge.
  • the spheres obtained are separated from the crystals formed in this same process. This separation can be done by combining sedimentation and filtration processes.
  • both the spheres and the separated crystals are washed with water and dried.
  • Titanium precursors can be selected from the group that comprises, but not limited to TiO 2 anatase type TiCI 3 , TiCI 4 , TiF 4 , Ti (SO 4 ) 2 , TiO 2 rutile type, mixtures of TiO 2 anatase type and rutile type or other organic compounds (such as isopropoxide and isobutoxide of titanium).
  • Silicon precursors can be selected from the group comprising, but not limited to sodium silicate, in the form of SiO 2 and Na 2 O, crushed quartz, silica sol, silica in the form of airgel or TEOS (tetraethylorthosilicate).
  • sodium and potassium precursors selected from the group comprising, but not limited to KOH, KCI, sodium silicate or other sodium and potassium salts are used: nitrates, acetates, oxalates , fluorides, etc.
  • the solution comprises the following molar ratios: 0.2-1.0 K 2 O: 0.1-0.4 Na 2 O: 1 SiO 2 : 0.005-0.25 TiO 2 : 20-100 H 2 O.
  • the solution comprises a molar ratio greater than 0.021 of TiO 2 / SiO 2 .
  • titanosilicate spheres or titanosilicate somorphs are obtained, obtainable by the described process.
  • titanosilicate spheres have the crystallographic structure of the microporous mineral called umbite.
  • the threshold has a crystalline structure consisting of octahedra of type MO 6 (where M is Ti) and tetrahedra TO 4 (where T is Si).
  • the structure of the spheres is hierarchized comprising the intrinsic micropores of the structure of the threshold and macropores. In addition, in this hierarchical structure the threshold crystals assembled to produce the spheres would have the crystallographic structure described in the present invention.
  • the spheres obtained by the process of the present invention can have a size of up to 3800 ⁇ m, and more preferably between 20 ⁇ m and 3800 ⁇ m in diameter, and a porosity, understood as a hollow volume, which is between 15 and 40 % of the sphere.
  • These spheres have a hierarchically organized micro / macroporous structure, showing a very low intraparticular resistance to water transport.
  • the behavior developed in the ion exchange is similar both in the case of the Ti-umbite spheres of the invention, and in that of the isolated crystals obtained in the same synthesis conditions.
  • the crystalline material of the umbite type is usually prepared in powder form or subsequently converted into tablets. In the case of the spheres of the present invention, it is not necessary to form the tablets afterwards, in a separate process, avoiding the addition of binders and thus giving rise to a maximum load of active material in the resulting assembly.
  • the spheres behave like powder crystals, in which it refers to adsorbing and retaining particles (ions and molecules), but without the problems associated with the handling and use of powders, such as, for example, the formation of aerosols, greater resistance to the transfer of matter, etc.
  • the use of the spheres described in the invention is provided, as an ion exchanger, to retain elements, which can be radioactive, soluble in their cationic form present in wastewater; as adsorbent material, as a desiccant of gaseous streams, as an adsorbent material, preferably as a desiccant of liquids and gases, for example as an adsorbent of NH 3 present in gaseous streams; as catalytic material; or as equipment elements of electronic and optoelectronic devices.
  • the spheres of the invention are used as an ion exchanger of the cations selected from the group comprising, but not limited to: Li + , Na + , K + , Rb + , Cs + , Fr + , Cu + , Ag + , Be 2+ , Mg 2+ , Sr 2+ , Ba 2+ , Ra 2+ , Mn 2+ , Hg 2+ , Co 2+ , Pb 2+ , Cd 2+ or Eu 3+ .
  • the spheres of the invention are used to retain the soluble radioactive elements in their cationic form, present in wastewater, selected from the group comprising, but not limited to: 60 Co, 90 Sr, 90 Y, 115 Cd, 131 I 1 137 Cs, 192 Ir, 204 Hg, 241 Am or 236 Pu.
  • FIG. 1a Shows some titanosilicate spheres by optical microscopy.
  • FIG. 1 b.- Shows a sphere by scanning electron microscopy;
  • FIG. 1c The surface of FIG. 1 B. by scanning electron microscopy;
  • FIG. 1d.- Shows the cross section of a sphere, after being embedded in resin and polished, by scanning electron microscopy (SEM);
  • FIG. 1e - Shows the core of FIG. 1d;
  • FIG. 2. Shows the accumulated intrusion of Hg and distribution of pore sizes of the spheres.
  • FIG. 3 (a, b, c) .- Shows SEM images of Ti-umbite crystals collected next to the spheres of FIG. one.; FIG. 3d.- Shows an image of pure Ti-umbite SEM.
  • FIG. 4. Shows the analysis by XRD (X-ray diffraction) of pure threshold, crystals of Exp. 2 and milled spheres of Exp. 2 and 3 (Table 1).
  • FIG. 5.- Shows the TiO 2 anatase compound, used as a precursor.
  • FIG. 6. Shows thermogravimetric analyzes of pure Ti-umbite, crystals and spheres of different sizes (200, 280 and 445 ⁇ m in diameter Exp. 2 and 280 ⁇ m in diameter in Exp. 9)
  • FIG. 7.- Shows the average diameter, together with its corresponding standard deviation, of the spheres, varying the rotation speed and synthesis time.
  • the Ti-umbite spheres were prepared by direct hydrothermal synthesis in the liquid phase, according to the following molar composition: 0.284 K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8 H 2 O. In some In cases, the molar fraction of TiO 2 was modified, studying the effect of said variable.
  • the precursor reagents used were: TiO 2 anatase (99.9 wt.%, Aldrich), KOH (85 wt%, Merck), KCI (99 wt%, Panreac) and a sodium silicate solution (25.5-28, 5 wt.% SiO 2 , 7.5-8.5 wt.% Na 2 O, Merck).
  • TiO 2 anatase 99.9 wt.%, Aldrich
  • KOH 85 wt%, Merck
  • KCI 99 wt%, Panreac
  • a sodium silicate solution (25.5-28, 5 wt.% SiO 2 , 7.5-8.5 wt.% Na 2 O, Merck).
  • To prepare a solution of 37.54 g of precursor gel 0.990 g of KCI and 1.010 g of KOH were dissolved in 56.90 mL of distilled water. Then, 0.424 g of TiO 2 anatase were added to the above solution with stirring
  • the autoclave was cooled in a stream of water, thus obtaining a mixture of Ti-umbite microspheres of a size of up to 700 ⁇ m in diameter and isolated crystals of up to 20 ⁇ m.
  • the spheres remained in the bottom of the autoclave, while the crystals were separated by filtration of the solution, washing both fractions (microspheres and crystals) with distilled water and allowing them to dry overnight in an oven at the temperature of 100 0 C.
  • Ti-umbite was also synthesized in following the procedure described in the article by Sebastián V. et al., (20).
  • Table 1 shows the different molar compositions used in this invention to synthesize the Ti-umbite titanosilicate.
  • the threshold spheres only occur under certain conditions of agitation, and a change in the speed of agitation entails a modification in the size distribution of the spheres.
  • the ionic exchange of Sr 2+ in the Ti-umbite was carried out by means of a solution of Sr (NO 3 ) 2 whose molarity was 0.025 M, using 100 mg of Ti-umbite in contact with 50 ml_ of Sr 2 solution + at room temperature and for 48 hours. Subsequently, the exchanged sample was washed with 50 mL of distilled water and dried at room temperature overnight. Through this procedure, some of the alkali metal ions (Na + and K + ) of the Ti-umbite were exchanged for Sr 2+ , giving rise to Sr x (Na 1 K) 2-2X TiSi 3 O 9 .
  • the different materials constituted by T ⁇ -umbita were characterized by scanning electron microscopy (SEM, JEOL JSM-6400) and X-ray diffraction (XRD, Philips X'pert MPD diffractometer, using CuKa as a radiation source). Hg intrusion porosimetry was also used by means of a Micromeritics AutoPore IV device.
  • Figure 1a shows a photograph taken with an optical microscope, giving a clear idea of the product obtained in a normal synthesis (Exp. 2): polycrystalline spheres of Ti-umbite are obtained, with sizes between 200 and 700 ⁇ m.
  • Figure 1b corresponds to a Ti-umbite sphere whose surface is shown in detail in Figure 1c, so that it can be seen how the spheres are constituted by crystals of dimensions between 6 and 7 ⁇ m.
  • the cross section of one of these spheres ( Figure 1d) reveals a good inter-growth, both in the nucleus and in the periphery of the sphere, the macroporos formed being visible.
  • the intrusion porosimetry of Hg confirms the presence in the macropore spheres of sizes between 0.2 and 1.4 ⁇ m. These macropores imply that the Ti-umbite spheres prepared in the invention are micro / macroporous hierarchical structures. The cumulative intrusion also shows that there is a small amount of larger macropores (approximately 10 ⁇ m), in addition to the total absence of mesopores. From the intrusion of Hg it was obtained that the porosity of these spheres is 22.6%. Together with the Ti-umbite spheres, isolated Ti-umbite crystals were also collected at the end of the synthesis. These crystals had an approximate length of 20 ⁇ m ( Figure 3a-c), thus being larger than those constituting the polycrystalline spheres.
  • ETS-1, 0 TiO 2 is fully transformed into the crystalline material corresponding to 200 0 C after 42 h (23).
  • Figure 4 compares the XRD diffractograms of pure threshold, synthesized using T ⁇ CI 3 instead of TiO 2 as a source of Ti and without any source of Na (20), with those of the threshold synthesized in the form of crystals and spheres according to Exp .2 (Table 1), and where a peak from the diffraction of TiO 2 can be observed, the rest of the precursor used in the synthesis of the spheres.
  • thermogravimetric analyzes Both crystals isolated as microspheres thermogravimetric analyzes were performed in a controlled atmosphere of N 2, until the temperature of 600 0 C with a heating ramp of 10 ° C / min, using a Mettler-Toledo equipment (TGA / SDTA851 e ). To carry out these thermogravimetric analyzes, the samples were hydrated at room temperature and for a period of three weeks, in closed plastic vials; so that the water they contained inside did not wet solid samples. In this way, it could be guaranteed that all the samples were saturated in water before carrying out the TG analyzes, since the analyzed samples were placed directly in the equipment from the vial containing them.
  • thermograms corresponding to different size umbilical spheres and to obtained threshold crystals can be observed under the same synthesis conditions, corresponding therefore to experiments 2 and 9 of Table 1.
  • the recorded thermogram ("Threshold" curve) is also represented from synthesized threshold crystals following the conventional procedure described in the article by Sebastián V. et al. (20) •
  • the conditions of experiment 9 provide umbite spheres with a lower unreacted anatase content, which confers an intermediate water retention capacity, as observed in Figure 6 ("Exp. 9").
  • the water adsorption or hydration capacity of the threshold is reversible, that is to say, that the percentages of water loss observed in Figure 6, around 5%, are related to the capacity of the threshold areas to adsorb water (and thus function as desiccants of liquids and gases) and molecules of similar size, such as, for example, ammonia.

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Abstract

Method for obtaining porous spheres of titanosilicate or isomorphous compounds of titanosilicate, by means of hydrothermal treatment of a solution including at least precursors of titanium or silicon, by controlling the temperature, reaction time, agitation speed, the precursor agents and the composition of the precursor solution. The invention also concerns the spheres obtainable using this method and the uses thereof.

Description

PROCEDIMIENTO DE OBTENCIÓN DE ESFERAS DE TITANOSILICATOS PROCEDURE FOR OBTAINING TITANOSILICATE SPHERES

La presente invención se refiere a un procedimiento para Ia obtención de esferas porosas de titanosilicatos, con una estructura jerarquizada, mediante tratamiento hidrotermal, controlando Ia temperatura, tiempo de reacción, agitación de los agentes precursores de titanio y silicio, y Ia composición de Ia disolución precursora. Además, Ia invención se refiere a esferas obtenibles por dicho procedimiento y el uso de las mismas.The present invention relates to a process for obtaining porous titanosilicate spheres, with a hierarchical structure, by hydrothermal treatment, controlling the temperature, reaction time, agitation of the titanium and silicon precursor agents, and the composition of the solution precursor In addition, the invention relates to areas obtainable by said method and the use thereof.

ESTADO DE LA TÉCNICA ANTERIORSTATE OF THE PREVIOUS TECHNIQUE

Los materiales zeolíticos presentan estructuras cristalinas que están constituidas por canales y cavidades con dimensiones moleculares. Estos materiales se aplican principalmente en procesos de intercambio iónico, adsorción y catálisis.The zeolitic materials have crystalline structures that are constituted by channels and cavities with molecular dimensions. These materials are mainly applied in ion exchange, adsorption and catalysis processes.

Sin embargo, Ia presencia de microporos puede menoscavar algunas veces su aplicación debido principalmente a las limitaciones difusionales intracristalinas. Esto es causa del transporte lento de los compuestos implicados en un determinado proceso a través de los canales de las partículas zeolíticas de mayor dimensión (1 ). Además, Ia mezcla que a veces es necesaria de las zeolitas con ciertos agentes (como, por ejemplo, aditivos de carácter aglomerante) puede disminuir Ia eficiencia de las propiedades del producto resultante conformado como pastilla, monolito, etc (2).However, the presence of micropores can sometimes undermine their application mainly due to intra-crystalline diffusional limitations. This is the cause of the slow transport of the compounds involved in a certain process through the channels of the largest zeolitic particles (1). In addition, the mixture that is sometimes necessary of the zeolites with certain agents (such as, for example, additives of a binding nature) can decrease the efficiency of the properties of the resulting product formed as a tablet, monolith, etc. (2).

Por el contrario, las partículas zeolíticas de dimensiones menores, en las cuales Ia longitud de los caminos difusionales se ve reducida, presentan un problema inherente de pérdida de carga y de riesgo de manipulación, debido a Ia posibilidad de formación de aerosoles potencialmente dañinos para el sistema respiratorio, además de Ia dificultad intrínseca que existe al separar los pequeños cristales zeolíticos por filtración como consecuencia de sus propiedades coloidales.On the contrary, the zeolitic particles of smaller dimensions, in which the length of the diffusion paths is reduced, present an inherent problem of loss of load and risk of manipulation, due to the possibility of formation of potentially harmful aerosols for respiratory system, in addition to the intrinsic difficulty that exists when the small zeolitic crystals are separated by filtration as a consequence of their colloidal properties.

Una posible solución a los problemas anteñores puede encontrarse en el uso de zeolitas con una arquitectura de poro jerárquica, esto es, que contienen micro y mesoporos (o también micro y macroporos) (3). Este tipo de zeolitas puede ser Ia solución a los problemas comentados, y por ello se están sintetizando de forma exitosa materiales jerárquicos con micro/mesoporos, meso/macroporos y micro/macroporos, donde generalmente el control de Ia porosidad bimodal se consigue mediante Ia combinación de determinados agentes directores de Ia estructura para Ia consecución así de Ia organización requerida (4).A possible solution to the problems before may be found in the use of zeolites with a hierarchical pore architecture, that is, they contain micro and mesopores (or also micro and macropores) (3). This type of zeolites can be the solution to the problems mentioned, and therefore hierarchical materials are being synthesized successfully with micro / mesopores, meso / macropores and micro / macropores, where generally the control of the bimodal porosity is achieved through the combination of certain managing agents of the structure for the achievement of the required organization (4).

Se han aplicado diversas técnicas para obtener diferentes estructuras jerárquicas zeolíticas a partir del denominado método del doble agente estructurante (5, 6): se han obtenido microesferas de silicalita-1 (7) y zeolita beta (8), utilizando para ello agentes directores de macro-estructuras (macroplantillas como resinas de intercambio aniónico particuladas con tamaños milimétricos); esferas huecas de silicalita-1 (macrocavidades y macroporos rodeados por un armazón continuo de zeolita) se han sintetizado a partir de esferas mesoporosas de sílice (9) y también cápsulas huecas de zeolita (silicalita-1 ) de forma no esférica (10); silicatos macroporosos con estructuras zeolíticas (silicalita-1 ) sintetizados mediante síntesis hidrotermal, utilizando como agentes directores de Ia estructura esferas monodispersas de poliestireno (6); o simplemente alternando capas de nanopartículas de silicalita-1 y macromoléculas cargadas opuestamente, que seguidamente se adsorben en esferas micrométricas de látex que posteriormente se ensamblan en monolitos macroporosos (11 ); películas mesoporosas y monolitos de silicalita-1 organizados de forma micro/meso/macroporosa se han preparado con gel de almidón como agente estructurante (4) y membranas zeolíticas porosas autosoportadas con arquitectura similar a las esponjas y microtubos zeolíticos se han sintetizado a partir de membranas porosas de acetato de celulosa (12).Various techniques have been applied to obtain different zeolitic hierarchical structures from the so-called double structuring agent method (5, 6): microspheres of silicalite-1 (7) and beta zeolite (8) have been obtained, using for this purpose director agents of macro-structures (macroplantillas as particulate anion exchange resins with millimeter sizes); hollow spheres of silicalite-1 (macrocavities and macropores surrounded by a continuous framework of zeolite) have been synthesized from mesoporous spheres of silica (9) and also hollow capsules of zeolite (silicalite-1) in a non-spherical shape (10); macroporous silicates with zeolitic structures (silicalite-1) synthesized by hydrothermal synthesis, using monodispersed spheres of polystyrene as guiding agents (6); or simply alternating layers of silicalite-1 nanoparticles and oppositely charged macromolecules, which are then adsorbed in micrometric latex spheres that are subsequently assembled into macroporous monoliths (11); Mesoporous films and silicalite-1 monoliths organized in a micro / meso / macroporous manner have been prepared with starch gel as a structuring agent (4) and self-supported porous zeolitic membranes with similar architecture to zeolitic sponges and microtubes have been synthesized from membranes porous cellulose acetate (12).

Los titanosilicatos del tipo ETS-4 y ETS-10 son materiales con propiedades similares a las zeolitas (13). Otro titanosilicato microporoso muy atractivo por sus posibilidades de aplicación, es el basado en el mineral umbita, K2(Zr0 8Tio 2)SÍ3θ9Η2O (14). El mineral umbita se puede sintetizar con diferentes estructuras isomórficas: K2ZrSi3O9-H2O (15), K2TiSi3O9-H2O (16), K2SnSi3O9-H2O (17) y K2ZrGe3O9-H2O (18). De forma similar a como sucede con ios titanosilicatos ETS-4 y ETS-10, los compuestos con estructura tipo umbita poseen una estructura cristalina constituida por octaedros del tipo MOβ (M= Zr, Sn, Ti) y tetraedros TO4 (T= Si, Ge). Este tipo de material cristalino se prepara en polvo o se convierte en pastillas para su uso posterior. Sus principales aplicaciones como polvo cristalino tienen que ver con el intercambio iónico de metales (19) y con Ia adsorción de pequeñas moléculas como amoníaco (22). Además, para otras aplicaciones, se han preparado membranas de umbita, capas policristalinas continuas, con aplicación en Ia separación de hidrógeno de mezclas H2/N2 H2/CO2 y H2/C3 H6 (20).Titanosilicates of the type ETS-4 and ETS-10 are materials with similar properties to zeolites (13). Another very attractive microporous titanosilicate for its application possibilities is that based on the mineral umbite, K 2 (Zr 0 8 Tio 2 ) YES 3 θ 9 Η 2 O (14). The mineral umbite can be synthesized with different isomorphic structures: K 2 ZrSi 3 O 9 -H 2 O (15), K 2 TiSi 3 O 9 -H 2 O (16), K 2 SnSi 3 O 9 -H 2 O ( 17) and K 2 ZrGe 3 O 9 -H 2 O (18). Similar to what happens with the ETS-4 and ETS-10 titanosilicates, compounds with an umbite-like structure have a crystalline structure consisting of octahedra of the MOβ type (M = Zr, Sn, Ti) and tetrahedra TO 4 (T = Si , Ge). This type of crystalline material is prepared in powder form or converted into tablets for later use. Its main applications as crystalline powder have to do with the ionic exchange of metals (19) and with the adsorption of small molecules such as ammonia (22). In addition, for other applications, threshold membranes, continuous polycrystalline layers have been prepared, with application in the separation of hydrogen from mixtures H 2 / N 2 H 2 / CO 2 and H 2 / C 3 H 6 (20).

EXPLICACIÓN DE LA INVENCIÓNEXPLANATION OF THE INVENTION

En Ia presente invención se han ensamblado cristales de Ti-umbita (K2TiSi3O9-H2O) por el procedimiento de síntesis hidrotermal, sin Ia utilización de agentes orgánicos directores de Ia estructura para conseguir así producir esferas sólidas de dimensiones micrométricas que combinan los microporos (los debidos a Ia Ti-Umbita) con macroporos, produciendo con ello una estructura zeolítica jerárquica de una amplia aplicación tecnológica en comparación con los propios cristales de Ti-umbita.In the present invention, Ti-umbite crystals (K 2 TiSi 3 O 9 -H 2 O) have been assembled by the hydrothermal synthesis procedure, without the use of organic agents that direct the structure to produce solid spheres of micrometric dimensions. that combine micropores (those due to Ti-Umbita) with macropores, thereby producing a hierarchical zeolitic structure of a wide technological application compared to the Ti-umbite crystals themselves.

Entendemos por "estructura zeolítica jerárquica", una estructura en Ia que poros de distintas dimensiones se combinan de una manera eficiente, mitigando problemas como los antes descritos. En particular, Ia estructura jerárquica obtenida en Ia presente invención conecta los macroporos entre las partículas que constituyen las esferas con los microporos intraparticulares, intrínsecos del titanosilicato, de tal forma que se reducen las resistencias al transporte, además de que se genera un conjunto macro-microporoso con un tamaño adecuado para su manejo en procesos industriales.We understand by "hierarchical zeolitic structure", a structure in which pores of different dimensions are combined in an efficient manner, mitigating problems such as those described above. In particular, the hierarchical structure obtained in the present invention connects the macropores between the particles that constitute the spheres with the intraparticular micropores, intrinsic to the titanosilicate, in such a way that transport resistance is reduced, in addition to generating a macro set microporous with a size suitable for handling in industrial processes.

La IUPAC (Unión Internacional de Química Pura y Aplicada) clasifica los poros en microporos (menores de 2 nm), mesoporos (entre 2 y 50 nm) y macroporos (mayores de 50 nm). Por otra parte, zeolitas son todos aquellos aluminosilicatos cristalinos, microporosos e hidratados. El término zeolítico se atribuye también a otros materiales que sin ser aluminosilicatos son microporosos y cristalinos (como los silicoaluminofosfatos, los aluminofosfatos, los titanosiilicatos, etc.), e incluso a otros que sin ser cristalinos están nanoestructurados y tienen mesoporos (como MCM-41 , MCM-48, SBA- 15, SBA- 16, etc.).The IUPAC (International Union of Pure and Applied Chemistry) classifies pores into micropores (less than 2 nm), mesopores (between 2 and 50 nm) and macropores (greater than 50 nm). On the other hand, zeolites are all those crystalline, microporous and hydrated aluminosilicates. The term Zeolitic is also attributed to other materials that, without being aluminosilicates, are microporous and crystalline (such as silicoaluminophosphates, aluminophosphates, titanosiilicates, etc.), and even to others that, without being crystalline, are nanostructured and have mesopores (such as MCM-41, MCM -48, SBA-15, SBA-16, etc.).

Por otro lado, al no utilizar agentes orgánicos directores de Ia estructura, no es necesario entonces una etapa de calcinación para lograr así Ia utilidad final del material, evitándose además el posible deterioro de Ia estructura que a menudo es resulta de las tensiones producidas durante el proceso de calcinación.On the other hand, since no organic agents are used to direct the structure, a calcination step is not necessary to achieve the final usefulness of the material, avoiding the possible deterioration of the structure that is often the result of the tensions produced during the calcination process

De acuerdo con un aspecto de Ia presente invención, se proporciona un procedimiento de obtención de esferas porosas de titanosilicato o de isomorfos de titanosilicato, mediante el tratamiento hidrotermal de una disolución que comprende al menos precursores de titanio o silicio, dicho tratamiento se lleva a cabo a una temperatura de reacción entre 180 y 250 0C en un tiempo de síntesis de entre 6 y 96 horas, con una velocidad de agitación de Ia disolución de entre 15 rpm y 60 rpm (revoluciones por minuto). Mediante este procedimiento se obtienen esferas y cristales individuales.In accordance with one aspect of the present invention, a process for obtaining porous titanosilicate or titanosilicate isomorphs is provided, by means of the hydrothermal treatment of a solution comprising at least titanium or silicon precursors, said treatment is carried out at a reaction temperature between 180 and 250 0 C in a synthesis time of between 6 and 96 hours, with a stirring rate of the solution between 15 rpm and 60 rpm (revolutions per minute). Through this procedure individual spheres and crystals are obtained.

Entendemos por "isomorfos de titanosilicato" compuestos donde el Ti se reemplaza por un átomo del grupo que comprende, pero sin limitarse a V, Zr, Sn ó Nb, y/o compuestos donde el Si se puede reemplazar por átomos de, pero sin limitarse a Ge.We understand by "titanosilicate isomorphs" compounds where Ti is replaced by an atom of the group comprising, but not limited to V, Zr, Sn or Nb, and / or compounds where Si can be replaced by atoms of, but not limited to to Ge.

En una realización preferida del procedimiento de Ia presente invención, las esferas obtenidas se separan de los cristales formados en este mismo proceso. Esta separación se puede realizar combinando procesos de sedimentación y filtración.In a preferred embodiment of the process of the present invention, the spheres obtained are separated from the crystals formed in this same process. This separation can be done by combining sedimentation and filtration processes.

En otra realización preferida del procedimiento de Ia invención, tanto las esferas como los cristales separados se lavan con agua y se secan.In another preferred embodiment of the process of the invention, both the spheres and the separated crystals are washed with water and dried.

Los precursores de titanio se pueden seleccionar del grupo que comprende, pero sin limitarse a TiO2 tipo anatasa TiCI3, TiCI4, TiF4, Ti(SO4)2, TiO2 tipo rutilo, mezclas de TiO2 tipo anatasa y tipo rutilo u otros compuestos orgánicos (como isopropóxido e isobutóxido de titanio).Titanium precursors can be selected from the group that comprises, but not limited to TiO 2 anatase type TiCI 3 , TiCI 4 , TiF 4 , Ti (SO 4 ) 2 , TiO 2 rutile type, mixtures of TiO 2 anatase type and rutile type or other organic compounds (such as isopropoxide and isobutoxide of titanium).

Los precursores de silicio se pueden seleccionar del grupo que comprende, pero sin limitarse a silicato sódico, en forma de SiO2 y Na2O, cuarzo triturado, sol de sílice, sílice en forma de aerogel o TEOS (tetraetilortosilicato).Silicon precursors can be selected from the group comprising, but not limited to sodium silicate, in the form of SiO 2 and Na 2 O, crushed quartz, silica sol, silica in the form of airgel or TEOS (tetraethylorthosilicate).

En una realización aún más preferida del procedimiento de Ia presente invención además se utilizan otros precursores de sodio y potasio seleccionados del grupo que comprende, pero sin limitarse a KOH, KCI, silicato sódico u otras sales de sodio y potasio: nitratos, acetatos, oxalatos, fluoruros, etc.In an even more preferred embodiment of the process of the present invention, other sodium and potassium precursors selected from the group comprising, but not limited to KOH, KCI, sodium silicate or other sodium and potassium salts are used: nitrates, acetates, oxalates , fluorides, etc.

En otra realización preferida del procedimiento de Ia presente invención Ia disolución comprende las siguientes relaciones molares: 0,2-1 ,0 K2O: 0,1- 0,4 Na2O: 1 SiO2: 0,005-0.25 TiO2: 20-100 H2O.In another preferred embodiment of the process of the present invention, the solution comprises the following molar ratios: 0.2-1.0 K 2 O: 0.1-0.4 Na 2 O: 1 SiO 2 : 0.005-0.25 TiO 2 : 20-100 H 2 O.

En otra realización más preferida del procedimiento de Ia presente invención Ia disolución comprende una relación molar superior a 0,021 de TiO2/SiO2.In another more preferred embodiment of the process of the present invention, the solution comprises a molar ratio greater than 0.021 of TiO 2 / SiO 2 .

De acuerdo con otro aspecto de Ia presente invención se proporcionan esferas de titanosilicato o ¡somorfos de titanosilicato, obtenibles por el procedimiento descrito.In accordance with another aspect of the present invention, titanosilicate spheres or titanosilicate somorphs are obtained, obtainable by the described process.

Estas esferas de titanosilicato tienen Ia estructura cristalográfica del mineral microporoso llamado umbita. La umbita tiene una estructura cristalina constituida por octaedros del tipo MO6 (donde M es Ti) y tetraedros TO4 (donde T es Si). La estructura de las esferas está jerarquizada comprendiendo los microporos intrínsecos de Ia estructura de Ia umbita y macroporos. Además, en esta estructura jerarquizada los cristales de umbita ensamblados para producir las esferas tendrían Ia estructura cristalográfica descrita en Ia presente invención. Las esferas obtenidas por el procedimiento de Ia presente invención pueden tener un tamaño de hasta 3800 μm, y más preferiblemente de entre 20 μm y 3800 μm de diámetro, y una porosidad, entendida como volumen hueco, que es de entre el 15 y el 40 % de Ia esfera.These titanosilicate spheres have the crystallographic structure of the microporous mineral called umbite. The threshold has a crystalline structure consisting of octahedra of type MO 6 (where M is Ti) and tetrahedra TO 4 (where T is Si). The structure of the spheres is hierarchized comprising the intrinsic micropores of the structure of the threshold and macropores. In addition, in this hierarchical structure the threshold crystals assembled to produce the spheres would have the crystallographic structure described in the present invention. The spheres obtained by the process of the present invention can have a size of up to 3800 μm, and more preferably between 20 μm and 3800 μm in diameter, and a porosity, understood as a hollow volume, which is between 15 and 40 % of the sphere.

Estas esferas presentan una estructura micro/macroporosa organizada jerárquicamente, mostrando una muy baja resistencia intraparticular al transporte de agua. Además el comportamiento desarrollado en el intercambio iónico es similar tanto en el caso de las esferas de Ti-umbita de Ia invención, como en el de los cristales aislados obtenidos en las mismas condiciones de síntesis.These spheres have a hierarchically organized micro / macroporous structure, showing a very low intraparticular resistance to water transport. In addition, the behavior developed in the ion exchange is similar both in the case of the Ti-umbite spheres of the invention, and in that of the isolated crystals obtained in the same synthesis conditions.

Estas esferas, al estar formadas de cristales intercrecidos, poseen gran resistencia mecánica.These spheres, being formed of intercreated crystals, possess great mechanical resistance.

El material cristalino de tipo umbita se prepara normalmente en polvo o se convierte posteriormente en pastillas. En el caso de las esferas de Ia presente invención no es necesario formar las pastillas después, en un proceso aparte, evitándose Ia adición de aglomerantes y dando lugar, por tanto a una máxima carga de material activo en el conjunto resultante.The crystalline material of the umbite type is usually prepared in powder form or subsequently converted into tablets. In the case of the spheres of the present invention, it is not necessary to form the tablets afterwards, in a separate process, avoiding the addition of binders and thus giving rise to a maximum load of active material in the resulting assembly.

Además, las esferas se comportan como los cristales en polvo, en Io que se refiere a adsorber y retener partículas (iones y moléculas), pero sin los problemas asociados al manejo y uso de polvos, como son por ejemplo, Ia formación de aerosoles, mayor resistencia a Ia transferencia de materia, etc.In addition, the spheres behave like powder crystals, in which it refers to adsorbing and retaining particles (ions and molecules), but without the problems associated with the handling and use of powders, such as, for example, the formation of aerosols, greater resistance to the transfer of matter, etc.

De acuerdo con otro aspecto más de Ia presente invención se proporciona el uso de las esferas descritas en Ia invención, como intercambiador iónico, para retener elementos, que pueden ser radiactivos, solubles en su forma catiónica presentes en aguas residuales; como material adsorbente, como desecante de corrientes gaseosas, como material adsorbente, preferiblemente como desecante de líquidos y gases, por ejemplo como adsorbente de NH3 presente en corrientes gaseosas; como material catalítico; ó como elementos de equipos de aparatos electrónicos y optoelectrónicos. En una realización preferida, las esferas de Ia invención se utilizan como intercambiador iónico de los cationes seleccionados del grupo que comprende, pero sin limitarse: Li+, Na+, K+, Rb+, Cs+, Fr+, Cu+, Ag+, Be2+, Mg2+, Sr2+, Ba2+,Ra2+, Mn2+, Hg2+, Co2+, Pb2+, Cd2+ ó Eu3+.In accordance with another aspect of the present invention, the use of the spheres described in the invention is provided, as an ion exchanger, to retain elements, which can be radioactive, soluble in their cationic form present in wastewater; as adsorbent material, as a desiccant of gaseous streams, as an adsorbent material, preferably as a desiccant of liquids and gases, for example as an adsorbent of NH 3 present in gaseous streams; as catalytic material; or as equipment elements of electronic and optoelectronic devices. In a preferred embodiment, the spheres of the invention are used as an ion exchanger of the cations selected from the group comprising, but not limited to: Li + , Na + , K + , Rb + , Cs + , Fr + , Cu + , Ag + , Be 2+ , Mg 2+ , Sr 2+ , Ba 2+ , Ra 2+ , Mn 2+ , Hg 2+ , Co 2+ , Pb 2+ , Cd 2+ or Eu 3+ .

En una realización preferida, las esferas de Ia invención se utilizan para retener los elementos radiactivos solubles en su forma catiónica, presentes en aguas residuales, seleccionados de grupo que comprende, pero sin limitarse: 60Co, 90Sr, 90Y, 115Cd, 131I1 137Cs, 192Ir, 204Hg, 241Am ó 236Pu.In a preferred embodiment, the spheres of the invention are used to retain the soluble radioactive elements in their cationic form, present in wastewater, selected from the group comprising, but not limited to: 60 Co, 90 Sr, 90 Y, 115 Cd, 131 I 1 137 Cs, 192 Ir, 204 Hg, 241 Am or 236 Pu.

A Io largo de Ia descripción y las reivindicaciones Ia palabra "comprende" y sus variantes no pretenden excluir otras características técnicas, aditivos, componentes o pasos. Para los expertos en Ia materia, otros objetos, ventajas y características de Ia invención se desprenderán en parte de Ia descripción y en parte de Ia práctica de Ia invención. Los siguientes ejemplos y figuras se proporcionan a modo de ilustración, y no se pretende que sean limitativos de Ia presente invención.Throughout the description and the claims, the word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and characteristics of the invention will emerge partly from the description and partly from the practice of the invention. The following examples and figures are provided by way of illustration, and are not intended to be limiting of the present invention.

BREVE DESCRIPCIÓN DE LAS FIGURASBRIEF DESCRIPTION OF THE FIGURES

FIG. 1a - Muestra algunas esferas de titanosilicatos por microscopía óptica. FIG. 1 b.- Muestra una esfera por microscopía electrónica de barrido; FIG. 1c- Ia superficie de Ia FIG. 1 b. por microscopía electrónica de barrido; FIG. 1d.- Muestra Ia sección transversal de una esfera, tras ser embebida en resina y pulida, por microscopía electrónica de barrido (SEM); FIG. 1e - Muestra el núcleo de Ia FIG. 1d; FIG. 1f.- Ia periferia de Ia FIG. 1d. por microscopía electrónica de barrido.FIG. 1a - Shows some titanosilicate spheres by optical microscopy. FIG. 1 b.- Shows a sphere by scanning electron microscopy; FIG. 1c- The surface of FIG. 1 B. by scanning electron microscopy; FIG. 1d.- Shows the cross section of a sphere, after being embedded in resin and polished, by scanning electron microscopy (SEM); FIG. 1e - Shows the core of FIG. 1d; FIG. 1f.- the periphery of FIG. 1d. by scanning electron microscopy.

FIG. 2.- Muestra Ia intrusión acumulada de Hg y distribución de tamaños de poro de las esferas.FIG. 2.- Shows the accumulated intrusion of Hg and distribution of pore sizes of the spheres.

FIG. 3(a,b,c).- Muestra imágenes de SEM de cristales de Ti-umbita recogidos junto a las esferas de Ia FIG. 1.; FIG. 3d.- Muestra una imagen de SEM de Ti-umbita pura. FIG. 4.- Muestra el análisis por XRD (difracción de Rayos X) de umbita pura, cristales del Exp. 2 y esferas molturadas de los Exp. 2 y 3 (Tabla 1 ).FIG. 3 (a, b, c) .- Shows SEM images of Ti-umbite crystals collected next to the spheres of FIG. one.; FIG. 3d.- Shows an image of pure Ti-umbite SEM. FIG. 4.- Shows the analysis by XRD (X-ray diffraction) of pure threshold, crystals of Exp. 2 and milled spheres of Exp. 2 and 3 (Table 1).

FIG. 5.- Muestra el compuesto de TiO2 anatasa, utilizado como precursor.FIG. 5.- Shows the TiO 2 anatase compound, used as a precursor.

FIG. 6.- Muestra los análisis termogravimétricos de Ti-umbita pura, cristales y esferas de diferente tamaño (200, 280 y 445 μm de diámetro Exp. 2 y 280 μm de diámetro en el Exp. 9)FIG. 6.- Shows thermogravimetric analyzes of pure Ti-umbite, crystals and spheres of different sizes (200, 280 and 445 μm in diameter Exp. 2 and 280 μm in diameter in Exp. 9)

FIG. 7.- Muestra el diámetro medio, junto con su correspondiente desviación estándar, de las esferas variando Ia velocidad de rotación y tiempo de síntesis.FIG. 7.- Shows the average diameter, together with its corresponding standard deviation, of the spheres, varying the rotation speed and synthesis time.

EJEMPLOSEXAMPLES

EJEMPLO 1EXAMPLE 1

Las esferas de Ti-umbita se prepararon mediante síntesis hidrotermal directa en fase líquida, de acuerdo con Ia siguiente composición molar: 0,284 K2O: 0,287 Na2O: SiO2: 0,095 TiO2: 30,8 H2O. En algunos casos se modificó Ia fracción molar de TiO2 estudiándose el efecto de dicha variable.The Ti-umbite spheres were prepared by direct hydrothermal synthesis in the liquid phase, according to the following molar composition: 0.284 K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8 H 2 O. In some In cases, the molar fraction of TiO 2 was modified, studying the effect of said variable.

Los reactivos precursores utilizados fueron: TiO2 anatasa (99,9 wt. %, Aldrich), KOH (85 wt %, Merck), KCI (99 wt %, Panreac) y una disolución de silicato sódico (25,5-28,5 wt. % SiO2, 7,5-8,5 wt. % Na2O, Merck). Para preparar una disolución de 37,54 g de gel precursor, se disolvieron 0,990 g de KCI y 1 ,010 g de KOH en 56,90 mL de agua destilada. Seguidamente, se añadieron a Ia disolución anterior bajo agitación 0,424 g de TiO2 anatasa.The precursor reagents used were: TiO 2 anatase (99.9 wt.%, Aldrich), KOH (85 wt%, Merck), KCI (99 wt%, Panreac) and a sodium silicate solution (25.5-28, 5 wt.% SiO 2 , 7.5-8.5 wt.% Na 2 O, Merck). To prepare a solution of 37.54 g of precursor gel, 0.990 g of KCI and 1.010 g of KOH were dissolved in 56.90 mL of distilled water. Then, 0.424 g of TiO 2 anatase were added to the above solution with stirring.

Aproximadamente después de 30 minutos de agitación se obtuvo una disolución con una dispersión homogénea. Finalmente, se añadieron 12,34 g de silicato sódico, manteniendo siempre Ia disolución en agitación. Así, después de agitar durante 60 minutos, se obtuvo una disolución blanca de aspecto poco viscoso. Si Ia dispersión de Ia disolución preparada no es Ia adecuada, las partículas de TiO2 anatasa van a precipitar cuando Ia agitación cese. El gel obtenido tras este proceso se introdujo en un autoclave construido en Teflón con carcasa de acero inoxidable, llenando aproximadamente el 90% de su capacidad (35 ml_). Seguidamente, se llevó a cabo una síntesis hidrotermal a 230 0C durante 6-96 h manteniendo en todo momento el autoclave en posición horizontal rotando (30-60 rpm).Approximately 30 minutes after stirring, a solution with a homogeneous dispersion was obtained. Finally, 12.34 g of sodium silicate were added, always keeping the solution under stirring. Thus, after stirring for 60 minutes, a white solution with a low viscous appearance was obtained. If the dispersion of the prepared solution is not adequate, the TiO 2 anatase particles will precipitate when the agitation cease. The gel obtained after this process was introduced in an autoclave built in Teflon with stainless steel housing, filling approximately 90% of its capacity (35 ml_). Then he took out a hydrothermal synthesis at 230 0 C for 6-96 h always maintaining the autoclave horizontally rotating (30-60 rpm).

Transcurrida Ia síntesis, se enfrió el autoclave en una corriente de agua, obteniendo así una mezcla de microesferas de Ti-umbita de un tamaño de hasta 700 μm de diámetro y cristales aislados de hasta 20 μm. Las esferas permanecieron en el fondo del autoclave, mientras que los cristales se separaron de Ia disolución por filtración, lavando ambas fracciones (microesferas y cristales) con agua destilada y dejándolas secar durante una noche en estufa a Ia temperatura de 100 0C.After the synthesis, the autoclave was cooled in a stream of water, thus obtaining a mixture of Ti-umbite microspheres of a size of up to 700 μm in diameter and isolated crystals of up to 20 μm. The spheres remained in the bottom of the autoclave, while the crystals were separated by filtration of the solution, washing both fractions (microspheres and crystals) with distilled water and allowing them to dry overnight in an oven at the temperature of 100 0 C.

Para comparar las esferas obtenidas, se sintetizó también Ti-umbita en siguiendo el procedimiento descrito en el artículo de Sebastián V. et al., (20).To compare the obtained spheres, Ti-umbite was also synthesized in following the procedure described in the article by Sebastián V. et al., (20).

La Tabla 1 muestra las diferentes composiciones molares utilizadas en esta invención para sintetizar el titanosilicato Ti-umbita. En primer lugar, hay que destacar que las esferas de umbita únicamente se dan bajo ciertas condiciones de agitación, y un cambio en Ia velocidad de agitación conlleva una modificación en Ia distribución de tamaños de las esferas.Table 1 shows the different molar compositions used in this invention to synthesize the Ti-umbite titanosilicate. In the first place, it should be noted that the threshold spheres only occur under certain conditions of agitation, and a change in the speed of agitation entails a modification in the size distribution of the spheres.

Si Ia síntesis hidrotermal se lleva a cabo durante tiempos inferiores a 6 horas, se obtiene una mezcla de Ti-umbita y material amorfo. Sin embargo, no sólo Ia velocidad de rotación es un factor crítico para Ia síntesis de esferas, sino que es necesario también tener en cuenta Ia composición del gel inicial de síntesis, así, conservando el resto de relaciones molares constantes, una relación de TiO2/SiO2 por debajo de 0,021 da origen únicamente a cristales aislados, independientemente de Ia velocidad de rotación seleccionada.If the hydrothermal synthesis is carried out for less than 6 hours, a mixture of Ti-umbite and amorphous material is obtained. However, not only the speed of rotation is a critical factor for the synthesis of spheres, but it is also necessary to take into account the composition of the initial synthesis gel, thus, keeping the rest of constant molar ratios, a TiO 2 ratio / SiO 2 below 0.021 gives rise only to isolated crystals, regardless of the selected rotation speed.

Tabla 1. Síntesis a una temperatura de 230 0C de esferas de Ti-umbita. Exp. Disolución Tiempo [r.p.m.] Productos [h]Table 1. Synthesis at a temperature of 230 0 C of Ti-umbite spheres. Exp. Dissolution Time [rpm] Products [h]

1 0,284K2O:0,287Na2θ:SiO2:0,095TiO2:30,8H2O 48 0 Cristales1 0.284K 2 O: 0.287 Na 2 θ: SiO 2 : 0.095 TiO 2 : 30.8H 2 O 48 0 Crystals

0,284K2O:0,287Na2O:SiO2:0,095TiO2:30,8H2O 96 Esferas + 2' 30 cristales0.284K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8H 2 O 96 Spheres + 2 '30 crystals

0,284K2O:0,287Na2O:SiO2:0,095TiO2:30,8H2O 48 Esferas +0.284K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8H 2 O 48 Spheres +

2 30 cristales2 30 crystals

0,284K2O:0,287Na2O:SiO2:0,095TiO2:30,8H2O 48 Esferas + 3 60 cristales0.284K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8H 2 O 48 Spheres + 3 60 crystals

0,284K2O:0,287Na2O:SiO2:0,095T¡O2:30,8H2O 24 30 Esferas + 4 cristales0.284K 2 O: 0.287 Na 2 O: SiO 2 : 0.095TO 2 : 30.8H 2 O 24 30 Spheres + 4 crystals

0,284K2O:0,287Na2O:SiO2:0,095TiO2:30,8H2O 12 30 Esferas + 5 cristales0.284K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8H 2 O 12 30 Spheres + 5 crystals

0,284K2O:0,287Na2O:SiO2:0,095TiO2:30,8H2O 6 30 Esferas + 6 cristales0.284K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8H 2 O 6 30 Spheres + 6 crystals

0,284K2O:0,287Na2O:SiO2:0,095TiO2:30,8H2O 30 Cristales + 7 amorfo0.284K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8H 2 O 30 Crystals + 7 amorphous

48 30 Esferas + 8 0,284K2O:0,287Na2O:S¡O2:0,032T¡O2:30,8H2O cristales48 30 Spheres + 8 0.284K 2 O: 0.287 Na 2 O: S¡O 2 : 0.032T¡O 2 : 30.8H 2 O crystals

Esferas +Spheres +

0,284K2O:0,287Na2O:S¡O2:0,021T¡O2:30,8H2O 48 30 cristales0.284K 2 O: 0.287 Na 2 O: S¡O 2 : 0.021T¡O 2 : 30.8H 2 O 48 30 crystals

10 0,284K2O:0,287Na2O:SiO2:0,017TiO2:30,8H2O 48 30 Cristales 1 1 0,414K2O:0,287Na2O:S¡O2:0,201TiO2:30,8H2O 48 30 Cristales10 0.284K 2 O: 0.287 Na 2 O: SiO 2 : 0.017 Ti 2 : 30.8H 2 O 48 30 Crystals 1 1 0.414K 2 O: 0.287 Na 2 O: S¡O 2 : 0.201 Ti 2 : 30.8H 2 or 48 30 crystals

EJEMPLO 2EXAMPLE 2

El intercambio iónico de Sr2+ en Ia Ti-umbita se realizó mediante una disolución de Sr(NO3)2 cuya molaridad era 0,025 M, utilizando en el intercambio 100 mg de Ti-umbita en contacto con 50 ml_ de disolución de Sr2+ a temperatura ambiente y durante 48 horas. Posteriormente Ia muestra intercambiada fue lavada con 50 mL de agua destilada y secada a temperatura ambiente durante una noche. Mediante este procedimiento de se intercambiaron algunos de los iones metálicos alcalinos (Na+ y K+) de Ia Ti-umbita por Sr2+, dando lugar a Srx(Na1K)2-2XTiSi3O9. Como resultado de este proceso se determina por ICP (análisis por plasma de acoplamiento inductivo) un 6,0 % en peso de Sr en las esferas de umbita, cuando en las mismas condiciones los cristales de umbita (obtenidos junto con las esferas) captan un 4,5 % del metal considerado. Este resultado es índice de que en las esferas de umbita presentadas aquí, Ia estructura jerárquica, los macroporos que conectan los cristales de umbita, hacen que Ia resistencia intraparticular al transporte de iones no sea limitante.The ionic exchange of Sr 2+ in the Ti-umbite was carried out by means of a solution of Sr (NO 3 ) 2 whose molarity was 0.025 M, using 100 mg of Ti-umbite in contact with 50 ml_ of Sr 2 solution + at room temperature and for 48 hours. Subsequently, the exchanged sample was washed with 50 mL of distilled water and dried at room temperature overnight. Through this procedure, some of the alkali metal ions (Na + and K + ) of the Ti-umbite were exchanged for Sr 2+ , giving rise to Sr x (Na 1 K) 2-2X TiSi 3 O 9 . As a result of this process, 6.0% by weight of Sr in the threshold areas is determined by ICP (inductive coupling plasma analysis), when under the same conditions the threshold crystals (obtained together with the spheres) capture 4.5% of the metal considered. This result is an index that in the threshold areas presented here, the hierarchical structure, the macropores that connect the threshold crystals, make the intraparticular resistance to ion transport not limiting.

EJEMPLO 3EXAMPLE 3

Los diferentes materiales constituidos por Tí-umbita fueron caracterizados por microscopía electrónica de barrido (SEM, JEOL JSM-6400) y difracción de rayos X (XRD, Philips X'pert MPD diffractometer, utilizando como fuente de radiación CuKa). También se utilizó Ia porosimetría por intrusión de Hg mediante un equipo Micromeritics AutoPore IV.The different materials constituted by Tí-umbita were characterized by scanning electron microscopy (SEM, JEOL JSM-6400) and X-ray diffraction (XRD, Philips X'pert MPD diffractometer, using CuKa as a radiation source). Hg intrusion porosimetry was also used by means of a Micromeritics AutoPore IV device.

La Figura 1a muestra una fotografía tomada con un microscopio óptico, dando una idea clara del producto obtenido en una síntesis normal (Exp.2): se obtienen esferas policristalinas de Ti-umbita, con tamaños comprendidos entre 200 y 700 μm. La Figura 1 b corresponde a una esfera de Ti-umbita cuya superficie se muestra en detalle en Ia Figura 1c, de forma que se puede apreciar cómo las esferas están constituidas por cristales de dimensiones entre 6 y 7 μm. La sección transversal de una de estas esferas (Figura 1d) revela un buen intercrecimiento, tanto en el núcleo como en Ia periferia de Ia esfera, haciéndose visibles los macroporos formados. La porosimetría por intrusión de Hg (Figura 2) confirma Ia presencia en las esferas de macroporos de tamaños entre 0,2 y 1 ,4 μm. Estos macroporos implican que las esferas de Ti-umbita preparadas en Ia invención son estructuras jerárquicas micro/macroporosas. La intrusión acumulativa muestra también que existe una pequeña cantidad de macroporos de mayor tamaño (aproximadamente 10 μm), además de Ia total ausencia de mesoporos. A partir de Ia intrusión de Hg se obtuvo que Ia porosidad de estas esferas es de 22,6 %. Junto con las esferas de Tí-umbita, también se recogieron al final de Ia síntesis cristales aislados de Ti-umbita. Estos cristales presentaban una longitud aproximada de 20 μm (Figura 3a-c), siendo así mayores que los que constituyen las esferas policristalinas.Figure 1a shows a photograph taken with an optical microscope, giving a clear idea of the product obtained in a normal synthesis (Exp. 2): polycrystalline spheres of Ti-umbite are obtained, with sizes between 200 and 700 μm. Figure 1b corresponds to a Ti-umbite sphere whose surface is shown in detail in Figure 1c, so that it can be seen how the spheres are constituted by crystals of dimensions between 6 and 7 μm. The cross section of one of these spheres (Figure 1d) reveals a good inter-growth, both in the nucleus and in the periphery of the sphere, the macroporos formed being visible. The intrusion porosimetry of Hg (Figure 2) confirms the presence in the macropore spheres of sizes between 0.2 and 1.4 µm. These macropores imply that the Ti-umbite spheres prepared in the invention are micro / macroporous hierarchical structures. The cumulative intrusion also shows that there is a small amount of larger macropores (approximately 10 μm), in addition to the total absence of mesopores. From the intrusion of Hg it was obtained that the porosity of these spheres is 22.6%. Together with the Ti-umbite spheres, isolated Ti-umbite crystals were also collected at the end of the synthesis. These crystals had an approximate length of 20 μm (Figure 3a-c), thus being larger than those constituting the polycrystalline spheres.

Además, se puede observar Ia capacidad de este material para cristalizar en forma de maclas (Figura 3a-c), Io cual está en pleno acuerdo con el intercrecimiento observado en Ia sección transversal de Ia Figura 1.In addition, the ability of this material to crystallize can be observed in the form of maclas (Figure 3a-c), which is in full agreement with the intercreation observed in the cross section of Figure 1.

Previamente también se ha utilizado en Ia síntesis de otros titanosilicatos, ETS-10, TiO2 anatasa y dependiendo de las condiciones de síntesis se ha detectado dicho óxido mediante análisis XRD en el producto final resultante. Esto implica que en el modelo de síntesis con TiO2, Ia etapa controlante podría ser Ia disolución de Ia anatasa, seguida por Ia condensación de los silicatos, con mayor facilidad de darse en Ia disolución (21 ). Como consecuencia de esta competencia de etapas, en Ia síntesis dePreviously it has also been used in the synthesis of other titanosilicates, ETS-10, TiO 2 anatase and depending on the synthesis conditions said oxide has been detected by XRD analysis in the resulting final product. This implies that in the synthesis model with TiO 2 , the controlling stage could be the dissolution of the anatase, followed by the condensation of the silicates, with greater ease of occurring in the solution (21). As a consequence of this competition of stages, in the synthesis of

ETS-1 ,0 el TiO2 es totalmente transformado en el material cristalino correspondiente a 200 0C después de 42 h (23).ETS-1, 0 TiO 2 is fully transformed into the crystalline material corresponding to 200 0 C after 42 h (23).

La Figura 4 compara los difractogramas de XRD de umbita pura, sintetizada utilizando TÍCI3 en lugar de TiO2 como fuente de Ti y sin ninguna fuente de Na (20), con los de Ia umbita sintetizada en forma de cristales y esferas según el Exp.2 (Tabla 1 ), y donde se puede observar un pico procedente de Ia difracción del TiO2, resto del precursor utilizado en Ia síntesis de las esferas.Figure 4 compares the XRD diffractograms of pure threshold, synthesized using TÍCI 3 instead of TiO 2 as a source of Ti and without any source of Na (20), with those of the threshold synthesized in the form of crystals and spheres according to Exp .2 (Table 1), and where a peak from the diffraction of TiO 2 can be observed, the rest of the precursor used in the synthesis of the spheres.

EJEMPLO 4EXAMPLE 4

Tanto para los cristales aislados como para las microesferas se realizaron análisis termogravimétricos, en atmósfera controlada de N2 y hasta Ia temperatura de 600 0C con una rampa de calentamiento de 10 °C/min, utilizando para ello un equipo Mettler-Toledo (TGA/SDTA851e). Para Ia realización de estos análisis termogravimétricos, las muestras se hidrataron a temperatura ambiente y durante un periodo de tres semanas, en unos viales cerrados de plástico; de manera que el agua que contenían en su interior no mojara a las muestras sólidas. De esta forma se podía garantizar que todas las muestras estuvieran saturadas en agua antes de realizar los análisis TG, ya que las muestras analizadas se disponían directamente en el equipo desde el vial que las contenía.Both crystals isolated as microspheres thermogravimetric analyzes were performed in a controlled atmosphere of N 2, until the temperature of 600 0 C with a heating ramp of 10 ° C / min, using a Mettler-Toledo equipment (TGA / SDTA851 e ). To carry out these thermogravimetric analyzes, the samples were hydrated at room temperature and for a period of three weeks, in closed plastic vials; so that the water they contained inside did not wet solid samples. In this way, it could be guaranteed that all the samples were saturated in water before carrying out the TG analyzes, since the analyzed samples were placed directly in the equipment from the vial containing them.

En Ia Figura 6 se pueden observar los termogramas correspondientes a esferas de umbita de diferentes tamaños y a cristales de umbita obtenidos en las mismas condiciones de síntesis, correspondientes por tanto a los experimentos 2 y 9 de Ia Tabla 1. Para que sirva de elemento de comparación, se representa también el termograma registrado (curva "Ti- umbita") a partir de cristales de umbita sintetizados siguiendo el procedimiento convencional descrito en el artículo de Sebastián V. et al.(20) • In Figure 6, the thermograms corresponding to different size umbilical spheres and to obtained threshold crystals can be observed under the same synthesis conditions, corresponding therefore to experiments 2 and 9 of Table 1. To serve as a comparison element, the recorded thermogram ("Threshold" curve) is also represented from synthesized threshold crystals following the conventional procedure described in the article by Sebastián V. et al. (20) •

Se puede ver, en esta Figura 6, cómo Ia pérdida de agua es casi idéntica en todos los materiales ("Exp. 2" correspondiente a esferas de diferentes diámetros, desde 200 hasta 445 μm, y cristales) obtenidos en las condiciones del experimento 2. Esto significa que, debido a Ia presencia en las esferas de los macroporos antes mencionados, Ia resistencia al transporte de agua no sería limitante. Por otra parte, Ia pérdida de agua es mayor para Ia umbita ("Tí-umbita") preparada en las condiciones que no dan lugar a esferas, Io que se atribuye a Ia ausencia de TiO2 anatasa sin reaccionar. La anatasa, a diferencia de Ia umbita no tiene porosidad, por tanto, mezclada con ésta, rebajaría su capacidad de adsorción de agua. Las condiciones del experimento 9 procuran esferas de umbita con un contenido en anatasa sin reaccionar menor, Io que confiere una capacidad de retención de agua intermedia, tal y como se observa en Ia Figura 6 ("Exp. 9"). La capacidad de adsorción de agua o de hidratación de Ia umbita es reversible, esto quiere decir, que los porcentajes de pérdida de agua observados en Ia Figura 6, alrededor del 5%, están relacionados con Ia capacidad de las esferas de umbita de adsorber agua (y así de funcionar como desecantes de líquidos y gases) y moléculas de tamaño similar, como, por ejemplo, el amoniaco.It can be seen, in this Figure 6, how the loss of water is almost identical in all materials ("Exp. 2" corresponding to spheres of different diameters, from 200 to 445 μm, and crystals) obtained in the conditions of experiment 2 This means that, due to the presence in the spheres of the macropores mentioned above, the resistance to water transport would not be limiting. On the other hand, the loss of water is greater for the threshold ("Thi-threshold") prepared in the conditions that do not give rise to spheres, which is attributed to the absence of unreacted TiO 2 anatase. Anatase, unlike the threshold does not have porosity, therefore, mixed with it, would reduce its water adsorption capacity. The conditions of experiment 9 provide umbite spheres with a lower unreacted anatase content, which confers an intermediate water retention capacity, as observed in Figure 6 ("Exp. 9"). The water adsorption or hydration capacity of the threshold is reversible, that is to say, that the percentages of water loss observed in Figure 6, around 5%, are related to the capacity of the threshold areas to adsorb water (and thus function as desiccants of liquids and gases) and molecules of similar size, such as, for example, ammonia.

EJEMPLO 5EXAMPLE 5

Se estudió también el efecto de Ia velocidad de rotación y del tiempo de tratamiento hidrotermal en el crecimiento de las esferas a 230 0C usando Ia composición molar: 0.284 K2O: 0.287 Na2O: SiO2: 0.095 TiO2: 30.8 H2O. En Ia Figura 7 se representa el diámetro medio, junto a su desviación estándar, en función del tiempo de síntesis y siendo el parámetro de las curvas Ia velocidad de rotación. De estas curvas se deduce que para una misma velocidad de rotación se pueden obtener esferas de diferentes tamaños en función del tiempo de síntesis elegido; y como para un mismo tiempo de síntesis Ia velocidad de rotación permite modificar el tamaño de las esferas. Todo esto abunda en Ia versatilidad del proceso propuesto aquí para obtener esferas de titanosilicato con estructura jerárquica. The effect of rotation speed and hydrothermal treatment time on spheres growth at 230 0 C was also studied using the molar composition: 0.284 K 2 O: 0.287 Na 2 O: SiO 2 : 0.095 TiO 2 : 30.8 H 2 O. In Figure 7 the average diameter is represented, together with its standard deviation, as a function of the synthesis time and the rotation speed being the parameter of the curves. From these curves it is deduced that for the same speed of rotation you can obtain spheres of different sizes depending on the synthesis time chosen; and as for the same time of synthesis the speed of rotation allows to modify the size of the spheres. All this abounds in the versatility of the process proposed here to obtain titanosilicate spheres with hierarchical structure.

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23. X. Yang, J. L. Paillaud, H.F.W.J. van Breukelen, H. Kessler, E. Duprey, Micropor. Mesopor. Mater. 46 (2001 ) 1-11. 23. X. Yang, J. L. Paillaud, H.F.W.J. van Breukelen, H. Kessler, E. Duprey, Micropor. Mesopor. Mater. 46 (2001) 1-11.

Claims

REIVINDICACIONES 1. Procedimiento de obtención de esferas porosas de titanosilicato o de compuestos isomorfos de titanosilicato, mediante el tratamiento hidrotermal de una disolución que comprende al menos precursores de titanio ó silicio, donde dicho tratamiento se lleva a cabo a una temperatura de reacción entre 18O0C y 250 0C en un tiempo de síntesis entre 6 y 96 horas, con una velocidad de agitación de Ia disolución de entre 15 rpm y 60 rpm.1. Process for obtaining porous titanosilicate spheres or isomorphic titanosilicate compounds, by hydrothermal treatment of a solution comprising at least titanium or silicon precursors, where said treatment is carried out at a reaction temperature between 18O 0 C and 250 0 C in a synthesis time between 6 and 96 hours, with a stirring speed of the solution between 15 rpm and 60 rpm. 2. Procedimiento según Ia reivindicación 1 , donde en los compuestos isomorfos de titanosilicato, el Ti se reemplaza por un átomo del grupo que comprende V, Zr, Sn, Nb2. Method according to claim 1, wherein in the isomorphic titanosilicate compounds, Ti is replaced by an atom of the group comprising V, Zr, Sn, Nb 3. Procedimiento según cualquiera de las reivindicaciones 1 ó 2, donde en los compuestos isomorfos de titanosilicato el Si se reemplaza por Ge.3. Method according to any of claims 1 or 2, wherein in the isomorphic titanosilicate compounds the Si is replaced by Ge. 4. Procedimiento según Ia cualquiera de las reivindicaciones 1 a 3, que además comprende Ia separación de las esferas de los cristales individuales formados en el mismo proceso.4. Method according to any one of claims 1 to 3, which further comprises separating the spheres of the individual crystals formed in the same process. 5. Procedimiento según Ia reivindicación 4, que además comprende lavar y secar las esferas separadas de los cristales.5. Method according to claim 4, further comprising washing and drying the spheres separated from the crystals. 6. Procedimiento según cualquiera de las reivindicaciones 1 a 5, donde los precursores del titanio y de silicio son TiO2 tipo anatasa y silicato sódico en forma de SiO2 y Na2O.Method according to any one of claims 1 to 5, wherein the titanium and silicon precursors are TiO 2 anatase type and sodium silicate in the form of SiO 2 and Na 2 O. 7. Procedimiento según cualquiera de las reivindicaciones 1 a 6, donde además se utilizan precursores de sodio y potasio seleccionados del grupo que comprende KOH, KCI, silicato sódico u otras sales de sodio y potasio.7. Method according to any one of claims 1 to 6, wherein sodium and potassium precursors selected from the group comprising KOH, KCI, sodium silicate or other sodium and potassium salts are also used. 8. Procedimiento según cualquiera de las reivindicaciones 1 a 7 donde Ia disolución comprende las siguientes relaciones molares, 0,2-1 ,0 K2O:8. Method according to any of claims 1 to 7 wherein the solution comprises the following molar ratios, 0.2-1, 0 K 2 O: 0,1-0,4 Na2O: 1 SiO2: 0,005-0.25 TiO2: 20-100 H2O. 0.1-0.4 Na 2 O: 1 SiO 2 : 0.005-0.25 TiO 2 : 20-100 H 2 O. 9. Procedimiento según cualquiera de las reivindicaciones 1 a 8, donde existe una relación de TÍO2/SÍO2 en Ia disolución es superior a 0,021.9. Method according to any of claims 1 to 8, where there is a ratio of UNCLE 2 / SIO 2 in the solution is greater than 0.021. 10. Esferas de titanosilicato o de compuestos isomorfos de titanosilicato ' . obtenibles por el procedimiento según cualquiera de las reivindicaciones 1 a 9.10. Titanosilicate spheres or isomorphic titanosilicate compounds. obtainable by the process according to any one of claims 1 to 9. 11. Esferas según Ia reivindicación 10, de un tamaño de hasta 3800 μm de diámetro.11. Spheres according to claim 10, of a size up to 3800 μm in diameter. 12. Uso de las esferas según cualquiera de las reivindicaciones 10 a 11 , como intercambiador iónico de cationes presentes en medio acuoso.12. Use of the spheres according to any of claims 10 to 11, as ionic cation exchanger present in aqueous medium. 13. Uso de las esferas según Ia reivindicación 12, para retener elementos radiactivos solubles en su forma catiónica..13. Use of the spheres according to claim 12, to retain soluble radioactive elements in their cationic form. 14. Uso de las esferas según cualquiera de las reivindicación 12 ó 13, donde el catión es Sr2+.14. Use of the spheres according to any of claims 12 or 13, wherein the cation is Sr 2+ . 15. Uso de las esferas según Ia reivindicaciones 10 a 11 , como material adsorbente.15. Use of the spheres according to claims 10 to 11, as adsorbent material. 16. Uso de las esferas según Ia reivindicación 15 como desecante de líquidos y gases. 16. Use of the spheres according to claim 15 as a desiccant of liquids and gases.
PCT/ES2008/000193 2007-04-03 2008-04-01 Method for obtaining spheres of titanosilicates Ceased WO2008119856A1 (en)

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