JPS59213615A - Membranous synthetic zeolite and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a titled membranous substance having excellent selectivity of material separation, durability, and heat resistance on a substrate by adding an alkali and water to a specified vitreous compd. CONSTITUTION:A vitreous compd. (e.g. borosilicate glass, soda ash glass), having a composition of 0.3-30wt%(%) X2O3, 50-99% YO2, 0-20% Na2O, and 0-10% ignition loss at 900 deg.C for an hour (X is Al, Ga, B; Y is Si, Ge), is used as a starting material, whereto an alkali and water is added to prepare a mixture having a composition of 0-0.01mol ratio of Na2O/H2O, 0.0002-0.02mol ratio of R/H2O, 1-200mol ratio of H2O/YO2 [R is organic cation and/or organic cationic source (e.g. tetrapropylammonium salt etc.)]. Then the reaction mixture is heated and kept in an autoclave to form a zeolite crystal layer having 1-500mu thickness on the surface of a substrate of glass. The product can be used as a satisfactory inorganic separation membrane.

Description

[Detailed description of the invention] The present invention relates to a separation membrane for separating substances.

More specifically, the present invention relates to a membrane zeolite for use as a separation membrane and a method for producing the same.

Conventionally, separation of substances using separation membranes has attracted attention due to its high efficiency, and has even been praised. However, since most of the separation membranes in use are made of organic substances such as polymers, they are insufficient in terms of patency and durability, as well as selectivity in material separation and energy loss during use. In addition, there was a drawback that the conditions of use were forced to be limited.

Therefore, in consideration of heat resistance and durability, inorganic separation membranes such as porous membranes and metal membranes are advantageous. However, these inorganic separation membranes generally have low separation efficiency;
Particularly in the case of metal films, there are drawbacks such as the fact that they are easily corroded, which greatly limits their applications, and therefore, inorganic separation groups have not been widely put into practical use.

On the other hand, crystalline aluminosilicate-1, which is generally known as crystalline zeolite, has a three-dimensional structure in which 5i04 regular tetrahedrons are bonded by sharing oxygen atoms.
The regular tetrahedron is a 4-membered ring, a 5-membered ring, an 8-membered ring, a 10-membered ring, or a 12-membered ring formed in succession.
It is known that the basic unit is a double ring formed by overlapping a membered ring and 4,6,8,10 and 12 membered rings, and that these are connected to determine the skeletal structure of crystalline aluminosilicate. It is being

A specific cavity exists in the skeletal structure determined by these connection methods, and the entrance of the cavity structure forms a cavity consisting of 6.8, 1O, and 12-membered rings. The cavities formed have a uniform diameter, and molecules below a certain size are adsorbed, but larger molecules are not allowed to enter the cavities. Thus, crystalline aluminosilicates are known as molecular sieves due to their properties, and are used industrially as adsorbents for various chemical processes, taking advantage of their dual properties.

Further, in crystalline aluminosilicate, aluminum in the skeleton structure has a tetrahedral structure and generates an (Ar04)- charge. In this case, various cations, such as sodium ions, are introduced to balance the charges.

Since this cation has ion exchange ability, it can be exchanged with cations such as various metal cations or ammonium ions to develop solid acidic points near where aluminum is present and to have a catalytic effect on crystalline aluminosilicate. It can be equipped.

In other words, the molecular sieve adsorption effect is: (1) a specific substance is adsorbed in the cavity determined by the skeletal structure, depending on the shape and size of the molecule, and (2) dipole formation occurs due to the action of cations present in the crystal structure. It is said that this occurs due to two mechanisms: adsorption of substances with quadrupoles, unsaturated bonds, and highly polarizable substances, but in general, cations are present in locations where they do not normally exhibit molecular sieving action. It is believed that.

Therefore, with the exception of cases where there is a significant change in cation diameter, such as in the case of potassium and sodium, or cases where there is a change in amount due to a difference in the number of charges of the cations, such as in the case of sodium and calcium, discussions regarding adsorption separation However, cationic species and their exchange rates have rarely been considered. However, when adsorbed species that interact with cationic species are mixed, for example, when water is present, adsorption inhibition due to strong adsorption becomes a major non-electrostatic problem. Silica-based materials exhibiting hydrophobicity are considered to be suitable for adsorption separation of such water-containing systems, and are actually effective in the case of separation of lower alcohols and water.

Based on these conventional findings, it is expected that if zeolite can be made into a membrane, the conventional drawbacks can be overcome and the inorganic substance content Fll Iff will be better than ever.

As a result of intensive research from this point of view, the present inventors have discovered that zeolite having a molecular sieve adsorption effect can be produced in the form of a membrane, and have arrived at the present invention.

Therefore, a first object of the present invention is to provide an inorganic membrane that has excellent selectivity in substance separation, durability, and heat resistance.

A second object of the present invention is to provide a membrane of zeta-synthesized zeolite 1- which inherently has excellent adsorption and separation functions.

Furthermore, a third object of the present invention is to provide a method for producing a synthetic zeolite membrane that maintains a crystalline structure that can have molecular sieve adsorption properties.

Such a compound of the present invention uses a glass compound (A) having the following composition as a raw material, prepares it into the following mixture CB), and then heats and maintains it in an autoclave to form a glass surface. 1 μm to 500 μm on the surface of the substrate
This was achieved by producing m theorite crystal layers.

Composition of glass compound (A): X2O30-50% by weight YO240-99% by weight Na2O0-20M1t% Loss on ignition 0-10% by weight (900°C 1:1a1) where X is selected from aluminum, gallium, and boron. Y is silicon, germanium, or a mixture thereof; Composition (molar ratio) of CB): Na2O/Ti20 0 to 0.01 (R)/H
200,0002~0.02H20/'YO21~20
0 Here, (R) is one or more organic nitrogen-containing cations and/or organic nitrogen-containing cation sources that can be arbitrarily selected, and Y is one or more selected from silicon and germanium. It is a mixture of them.

Crystalline aluminosilicates are commonly used with 5i02 as the silicon source.
, an aqueous reaction mixture is prepared using Al2O2 as an aluminum source in a certain range of ratios, and a suitable alkali source and water are added in a certain range of ratios, and this aqueous reaction mixture is used to form crystals. It can be produced by heating and maintaining the crystallization temperature up to the crystallization temperature. Such manufacturing conditions include, for example, autogenous pressure, about 20°C to about 23°C.
This is achieved by maintaining m1 at 0° C. for about 10 hours to about 10 days.

In this case, silicon sources include, for example, sodium silicate, silica gel, silicic acid, aqueous colloidal silica gel-dissolved silica, powdered silica, or amorphous silicate, among which sodium silicate, water glass,
Colloidal silica is preferred.

Further, as an aluminum source, for example, activated alumina, T
- Examples include various aluminum salts such as alumina, alumina trihydrate, nitrates, and sulfates, with sodium aluminate and aluminum sulfate being particularly preferred.

In the present invention, these raw materials may be mixed separately and used, but the elements represented by the general formula
A glass compound containing an oxide of a group element, 5i02 and/or GeO2, and if necessary further Na2O is preferable, and the above glass compound whose loss on ignition at 900° C. for 1 hour is 0 to 10% by weight is particularly preferable. 7.

Although the glass compound (A) used in the present invention is amorphous, it contains silicon and/or germanium in the form of YO2, and is an oxidized compound in which tetrahedra are bonded to each other by sharing one oxygen. It has become a thing. Preferred X that can be contained in this glass compound is boron, aluminum, and gallium, and since these can have a tetrahedral structure like the above-mentioned silicon and germanium, they can form zeolite.

Therefore, by carrying out a hydrothermal reaction using the above glass compound (A) as a starting material and adding an alkali source during this hydrothermal reaction, the solid phase in the reaction product is once melted to form a zeolite nucleus, and then Due to the growth of crystals, a zeolite film can be formed.

In this case, if gel is present in the reactant, this gel becomes a solid amorphous phase, which directly transforms into a crystalline phase to form zeolite, so it is not possible to obtain zeolite lumps or powder. However, it is not possible to obtain membrane-like zeolite. Therefore, it is necessary to exclude gel from the reaction.

In order to easily precipitate and set zeolite crystals by the hydrothermal reaction of the present invention, the composition of the raw material glass compound must be within a certain range.

That is, the total content of x203 contained in the glass compound (A) used in the present invention is 0 to 50% by weight, preferably 0.
The total content of YO2 is 9% to 40% to 99% by weight.
It is preferably 50 to 99 M%. Also, Na2
Preferred values for O are 0 to 20% by weight. As an example of such a glass compound as a raw material, let's take a look at 4.
Examples include borosilicate glass, soda ash glass, aluminosilicate glass, warp glass, etc. 1. As the alkali added during the hydrothermal reaction in the present invention, commonly used alkalis can be used. In order to grow crystals from the phase and form the legs of zeolite 1-,
Since it is important to control the alkali concentration, this H
In particular, expressed as a molar ratio, Na2O/'H200~0.01 (R)/H200,0002~0.02 (here, [R
) is one or more organic nitrogen-containing cations and/or organic nitrogen-containing cation sources that can be selected arbitrarily) and a mixture CB) represented by H20/YO21-200 is preferable. .

Here Na2O is @l'! Na2O in It and Na2O in the glass compound (A), which can be adjusted by adding sulfuric acid, hydrochloric acid, sulfuric acid, etc.
Ru.

The organic nitrogen-containing cation source used in the present invention can increase the pH under hydrothermal reaction conditions, thereby increasing oligomers such as dimers and trimers of siliceous ions and crystallizing them from solution. It is possible to create an environment where it is easy to precipitate. In the present invention, the organic nitrogen-containing cation source used for this purpose may be used alone or in any combination of two or more.

Such organic nitrogen-containing cation sources include, for example, tetramethylammonium salt, tetraethylammonium salt, tetrapropylammonium salt, tetrabutylammonium salt, diethylammonium salt, triethylammonium monomer, diheny/dylammonium salt, dibenzyldiethylammonium salts, quaternary ammonium salts such as dibenzyldiethylammonium salt, hensyltrimethylammonium salt or choline salt, such as trimethylamine, triethylamine, tripropylamine, ethylenediamine, propanediamine, butanediamine, pentanediamine, hexanediamine, methylamine, Examples include alkylamines such as ethylamine, propylamine, butylamine, dimethylamine, diethylamine, and dipropylamine, aromatic amines such as lindylamine and aniline, and cyclic amines such as pyridine, piperidine, or pyrrolidine. However, among these, tetrapropylammonium salts, propylamine and derivatives thereof are particularly preferred.

As described above, since the alkali concentration greatly influences the growth of zeolite crystals, in the present invention, by controlling the alkali concentration, the thickness of the zeolite membrane to be formed can be easily made into a thickness of IIl.

In the present invention, a substrate is required for depositing glue-like zeolite crystals. As such a substrate, for example, glass, mullite and copeillite ceramics, alumina, silica, etc., and metals or other substrates coated with inorganic materials can be used, but among these, glass is particularly suitable. In this case, zeolite crystals precipitate quickly and the formed film is in good condition, so silicate glass is particularly preferred among glasses. Examples of such silicate glasses include 5i
Quartz glass containing 02 as the main component, Na2O-3i02
Alkali silicate glass with Na20-Ca as the main component
Soda lime glass with O-3i02 as the main component, K7
, 0-CaO-3i02 as the main component, lead (alkali) glass as the main component in K2O-pbo-sto2, barium glass as the main component in BaO-3i02-8203, Na20-B2O3-5io
Examples include borosilicate glass containing 2 as a main component. Among these, it is particularly preferable to use one that is substantially the same as the strong glass compound [A]. In this way, the glass layer whose surface is covered with film-like zeolite (this is referred to as the intermediate layer in the present invention) has a tendency to have an increased Na2O ratio compared to the initial composition ratio, but still It remains amorphous and does not sufficiently play the role of supporting body of membrane zeolite.

In the hydrothermal reaction of the present invention, mineralization 7I during crystallization
It is possible to add lj. Mineralizers are those that can promote the formation of zeolite, and examples of such mineralizers include NaCβ, Na2CO3,
N a 2 S 04, N a 2 S (404, K
CI! ,,KBr,,KFSBaCI! 2 or BaBr
Mention may be made of neutral salts of alkaline or alkaline earth metals such as 2. Among these mineralizers, especially NaC
14 is preferred.

The zeolite formed on the glass surface by the zeolite membrane synthesis method of the present invention is taken out from the reaction vessel, washed with pure water, dried at room temperature to 120°C for 1 to 16 hours, and
When observed with a secondary electron microscope (SEM), it can be seen that the
It appears that large crystal grains of m are coalesced in some form.

Therefore, the X-ray diffraction of membranous zemerite shows a pattern similar to that of a single crystal, and as shown in Table 1, many new peaks appear within the six main peaks that also appear in the case of a single crystal.

Table 1 11.2 ±0.2 Strong 10.1 ±0.2 Strong 3.86±0.05 Very strong 3.76±0.05 Strong 3.72±0.05 Strong 3.64±0. 05 Strong and two or more diffraction peaks exist between 3.76 people and 3.72 people, and one or more diffraction peaks exist between 3.72 people and 3.64 people.

However, this result was measured by a conventional method using a WX-ray diffraction apparatus (Geigerflex RAD-rA type) manufactured by Rigaku Denki Co., Ltd.

The radiation is a doublet of copper, and a scintillation counter with a strip chart pen recorder is used to read the peak height and its position as a function of 20 (θ is the Bragg angle) from the chart. From these,
The relative intensity for the recorded lines and the lattice spacing (d) expressed in Onges 1-Roam units are measured.

The composition of the giolide of the present invention obtained in this way is expressed as the molar ratio of oxides, and is as follows: 0-1.0Na20・0.1-1.0ΣRR' 0・X
2O3・10-10.000YO2・0~4. OH2
It was 0.

However, R and R'' in RR'O represent organic nitrogen-containing cations that may be different from each other, and two or more organic nitrogen-containing cation sources may be optionally mixed during the hydrothermal reaction of the present invention.
ΣRR'O, as used, means the sum of all RR''0 resulting from all combinations of R and R'' present in the reaction system.

The membranous synthetic zeolite obtained by the present invention originally has
Since it is a zeolite that has the function of selective adsorption and separation of molecules, it is expected that its I$7J'R separation performance will be extremely good.

As mentioned above (in general, crystalline alumino J according to the present invention,
[The balance of electrons in the aluminum-containing tetrahedron of sodium is maintained by retaining cations such as sodium ions within the crystal. These cations can be ion-exchanged by various methods to become a hydrogen type or metal ion exchange type, and function as a solid acid catalyst.

At least a portion of the intermetallic ions present during synthesis can also be replaced by ion exchange or the like. Ion exchange can be carried out using hydrogen ions such as metals or parts of Groups I to II of the Periodic Table of the Elements, or using ammonium ions. In the case of the membranous synthetic zeolite of the present invention This fact can also be utilized, and this makes it possible to produce substances in various forms (5b).

Furthermore, the substance separation membrane obtained in the present invention has high heat resistance because it contains inorganic zeolite e, making it possible to separate substances under temperature conditions that could not be used conventionally. This not only expands the scope of use of material separation, but also reduces and reduces energy loss in the material separation process, and therefore the present invention is of great significance. In connection with this, the durability of the material separation membrane is also improved, and the present invention has great benefits for the development of industry! I'm an Ian Meko dog.

The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto.

Example 1 Borosilicate glass with a wall thickness of 1.05 m (Si0295°3 type car%, B2032.8'1MM%, A, i'2030.
2GgHi%, Na200.02wt%) 4°5g,
lf7r with 0.6 g of NaOH and 1.9 g of tetrabropylammonium J1 bromide dissolved in 131 g of pure water.
: After putting it together with θ in a 200 cc capacity O-crane and sealing it, the temperature was raised while shaking, and the temperature was increased to 190'.
C and held for 64 hours. After the reaction was completed, the borosilicate glass was taken out from the autoclave, washed with L2 water, and dried at 100° C. for about 16 hours.

A translucent zeolite layer was formed on the surface M of the transparent glass. Powder X-ray diffraction analysis of the produced zeolite revealed that it was a zeolite exhibiting the X-ray diffraction characteristics listed in Table 1, and the thickness of the scale was approximately 5 μm. The reaction conditions and experimental results are shown in Table 2.

Example 2 As shown in Table 2, an experiment was conducted in the same manner as in Example 1 except that the amount of NaOH added was changed.

A translucent layer was formed on the surface layer of the transparent glass, the thickness of which was approximately 113 μm. When this was analyzed by powder X-ray diffraction method, it was a zeolite showing basically the same X-ray diffraction pattern as in Example 1.

Example 3 As shown in Table 2, an experiment was conducted in the same manner as in Example 1, except that the amount of NaOH added was changed.

Transparent, -(A translucent layer was formed on the surface of the glass, and the thickness of the IF was about 170.am. When this was analyzed by powder X-ray diffraction method, it was found that it was Example 1. The zeolates showed essentially the same X-ray diffraction pattern.Example 4 Porous borosilicate glass with a wall thickness of 1.15E11 (surface area of 16
5.4I+(/'g, SiO?, 88.7% market weight, B
2C1) D2.671% by weight, A#2030.24% by weight
, Na 200.02imti%) 2.5g, NaOH0.5g1 tetrapropylammonium bromide 1.06g and NaCj! to 73.4g of pure water. Pour 5.1 g of the solution into a 200 cc autoclave, seal it, and raise the temperature to 193 ml while shaking.
℃ and held for 63 hours. After the reaction, the reaction product was taken out from the autoclave, washed with pure water, and heated to 100°C.
Let it dry for about 16 hours.

The surface layer of the reactants formed a translucent layer, and the thickness of this layer was approximately 325 μrn. When this was analyzed by powder X-ray diffraction, it was found to be zeolaite showing basically the same X-ray diffraction pattern as in Example 1. The experimental results are shown in Table 2.

Comparative Example As shown in Table 2, an experiment was conducted in the same manner as in Example 4, except that tetrapropylammonium bromide was not used.

Translucent debris 1L1' was formed on the surface layer of the reactant, and analysis of this by powder X-ray diffraction revealed that it was amorphous.

Example 5. ~9° An experiment was conducted in the same manner as in Example 4, except that the Na 20 /S i 02 molar ratio was different. The experimental results are shown in Table 3.
As shown in Figure 2, membrane-like synthetic theolite was obtained in all cases.

Patent applicant: Toa Fuel Industries Co., Ltd.

Claims (1)

[Claims] (1) Membrane-like synthetic zeolite characterized by having a thickness of 111 m to 500 μm. 2) The membranous synthetic zeolite according to claim 1, wherein 90% by weight or more of the synthetic zeolite is crystalline synthetic zeolite. 3) The membranous synthetic zeolite according to claim @1, wherein the X-ray powder diffraction pattern of the crystalline portion has the following characteristics. Lattice Blood Punishment-Brain d (AJ-Shitsu-l111.2 ±0
．． 2 Strong l001 ±0.2 Strong 3.86 0.05 Very strong 3.76 ± 0.05 Strong 3.72 ± 0.05 Strong 3.64 ± 0.05 Strong and 3.76 eight and 3 There are two or more diffraction peaks between .72A and one or more diffraction peaks between 3.72A and 3.64A. 4) The molar ratio of the oxide is 0 to 1. ON;y20-0.1~1.0Σ)? R' 0
・X2O3・10~10,000YO2・O~4. O
H20 (where R and R' are organic nitrogen-containing cations that may be different from each other, and ΣRR'O represents all the RR'Os produced by the combination of R and R' present in the synthesis reaction system. X is one selected from aluminum, gallium, and boron or a mixture of 2M or more, and Y is silicon or germanium or a mixture thereof. Membrane-like synthetic zeolite according to claim 3. 5) Using a glass compound [A] having the following composition as a starting material, add an alkali and water to it to cleave a mixture (B) having the following composition, and use this reaction mixture to form a zeolite crystal layer on the glass surface. A method for producing a membrane-like synthetic zeolite, which comprises heating and maintaining it at a crystallization temperature in a reaction vessel. Composition of glass compound (A): X2O30, 3 to 30% by weight YO250 to 99% by weight Na20 0 to 20% by weight Loss on ignition 0 to 10% by weight (900°C for 1 hour) where X is aluminum, gallium, One type or a mixture of two or more types selected from boron; Y is one type selected from silicon and germanium or a mixture thereof; Composition (molar ratio) of mixture CB): Na 20 / H200~0. 01 (R)/H-zOO,0002~0.021120/Y
O21-200 Here, (R) is one or more organic nitrogen-containing cations and/or organic nitrogen-containing cation sources that can be arbitrarily selected, and Y is IM selected from silicon and germanium. or a mixture thereof.