CN111302358A - Binder-free FAU type molecular sieve particles and preparation method and application thereof - Google Patents
Binder-free FAU type molecular sieve particles and preparation method and application thereof Download PDFInfo
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Abstract
The invention provides a binder-free FAU type molecular sieve particle, a preparation method and an application thereof, wherein the method comprises the following steps: 1) taking an alkaline solution dissolved with an aluminum source as a water phase, and sequentially adding a surfactant aqueous solution and an oil phase on the upper part of the alkaline solution; 2) adding a silica gel mixture obtained by uniformly mixing a gelling agent and silica sol into the mixture, and allowing the mixture to pass through an oil phase and a surfactant phase to reach a water phase to obtain a silica gel precursor; and 3) removing the oil phase and the surfactant phase, and aging and crystallizing the silicon gel precursor and the water phase together to obtain the FAU type molecular sieve particles without the binding agent. Compared with the prior art, the prepared FAU molecular sieve particles without the binding agent have larger specific surface area, larger hexene adsorption capacity, high adsorption/desorption rate and excellent coking resistance.
Description
Technical Field
The invention belongs to the technical field of inorganic synthetic materials, and particularly relates to FAU type molecular sieve particles without a binder, and a preparation method and application thereof.
Background
Molecular sieves have been widely used in the adsorptive separation, catalytic and cation exchange industries because of their advantages of good stability, unique shape selectivity, adjustable pore structure, large specific surface area, mature preparation process, etc. The FAU type molecular sieve can be divided into X type and Y type molecular sieves, wherein the X type molecular sieve refers to the ratio of silicon to aluminum [ n (Si)/n (A1)]The molecular sieve is a faujasite molecular sieve of 1 to 1.5, and the Y-type molecular sieve is a silica-alumina ratio [ n (Si)/n (A1)]The faujasite molecular sieve is a faujasite molecular sieve of 1.5-3, and the X-type molecular sieve and the Y-type molecular sieve have the same crystal structure. The FAU type molecular sieve can utilize the difference of interaction force between adsorbate molecules and molecular sieve active sites to realize selective adsorption separation of the molecular sieve, and is often used for separating olefin/alkane and CO2/CH4、N2/CH4And the like. The adsorption performance of the molecular sieve can be changed by modifying the FAU type molecular sieve with different metal ions (such as Mg, Mn, Fe, Co, Ni, Zn and the like).
At present, the process for preparing the FAU type molecular sieve by hydrothermal synthesis is mature, but the molecular sieve synthesized by the method in industry is generally crystal powder, and if the molecular sieve is directly applied to industrial production, the problems of large dust, environmental pollution, inconvenient operation, large bed pressure drop, difficult recovery, easy inactivation, easy aggregation and the like can exist. Therefore, in industrial practice, it is usually necessary to add a certain amount (about 20% by mass) of a binder (clay, kaolin, silica sol, etc.) to give it a specific shape (stripe, block, sphere, etc.) and a certain mechanical strength. However, the added binder is an adsorption ineffective component, so that the addition of the binder not only dilutes the content of the effective component (i.e., FAU type molecular sieve crystals) in the product, resulting in a decrease in adsorption capacity; but also can block partial pore channels of the molecular sieve, thereby causing adverse effects on the diffusion and mass transfer of adsorbate in the molecular sieve, causing the reduction of the adsorption/desorption rate of the molecular sieve and greatly influencing the adsorption performance of the molecular sieve. In addition, the added binder has no adsorption selectivity, so that the adsorption selectivity of the FAU type molecular sieve to a system to be separated is reduced, namely the adsorption separation efficiency is reduced. In addition, the binder can cause adverse side reactions, for example, the metal oxide component contained in the mineral binder can catalyze the condensation of unsaturated hydrocarbons, accelerate the coking and inactivation of the FAU-type molecular sieve in the adsorption or catalytic reaction process, and shorten the regeneration period and the service life of the FAU-type molecular sieve.
An effective solution to the adverse effects of binders is to use binder-free molecular sieve particles in an industrial process. At present, the process for synthesizing the molecular sieve without the adhesive mainly comprises an adhesive conversion method and a direct preparation method. The binder conversion method is also a relatively common method for synthesizing binder-free molecular sieves, and is to add some mineral clay into the powder molecular sieve, shape the powder molecular sieve and achieve relatively high mechanical strength to meet industrial application, and convert the binder into the target molecular sieve through secondary hydrothermal treatment. This method is cumbersome to operate, requires two hydrothermal syntheses, and the second hydrothermal treatment may adversely affect the original molecular sieve crystals, and in addition, the binder components are difficult to completely convert. The direct preparation method is also called as in-situ synthesis method, which is to prepare the embryo particles containing the aluminum source or the silicon source in advance, then add the embryo particles into the prepared crystallization mother liquor, and directly convert the embryo particles into the molecular sieve particles with specific structures after hydrothermal treatment. The method has obvious advantages in adsorption performance because no binder is added.
The existing in-situ synthesis process of the binderless molecular sieve particles mainly aims at the A-type molecular sieve, and patents US3359068 and US3348911 report a process for preparing a binderless spherical A-type molecular sieve by a two-step method. The method relates to high-temperature hot oil, and has great environmental pollution. Patent CN 87105499a also discloses a two-step method for preparing binderless spherical a-type molecular sieve. The method is optimized to the method, high-temperature hot oil is replaced by low-temperature oil phase, and pollution is effectively reduced. However, these methods require two steps to prepare the binderless spherical A-type molecular sieve, i.e. the binderless spherical A-type molecular sieve is prepared by synthesizing silica spheres by using forming oil, aging, washing with water, drying, roasting and the like, and then crystallizing the silica spheres in crystallization mother liquor. In the prior art, corresponding embryo bodies are prepared firstly, and then are converted into target molecular sieves through corresponding hydrothermal treatment after separation, washing, drying and other processes, so that the process flow is complicated.
Literature Synthesis of binderless Zeolite X microspheres and theirCO2adsorption properties Technology (Separation and Purification Technology, 2013, vol. 118, p. 188) binder-free spherical X-type molecular sieves were prepared by a chitosan-assisted technique. The technology is simply described as that in sodium metaaluminate alkaline solution, silica/chitosan mixed microspheres are treated by dipping, gel-hydrothermal synthesis to obtain molecular sieve/chitosan hybrid microspheres, and then the chitosan is removed by calcination to prepare the binderless X-type molecular sieve microspheres, and the technology essentially adopts organic chitosan as a binder.
At present, no report of in-situ synthesis of binder-free FAU type molecular sieve particles by a one-pot method is found.
Disclosure of Invention
The invention aims to provide binder-free FAU type molecular sieve particles and a preparation method and application thereof, so that the problems that the preparation method of the binder-free FAU type molecular sieve particles in the prior art relates to high-temperature hot oil, the environmental pollution is large and the process flow is complicated are solved.
In order to solve the problems, the invention adopts the following technical scheme:
according to a first aspect of the present invention, there is provided a method for preparing binderless FAU-type molecular sieve particles, comprising the steps of: 1) taking an alkaline solution dissolved with an aluminum source as a water phase, and sequentially adding a surfactant aqueous solution and an oil phase on the alkaline solution to form a three-phase system containing an oil phase, a surfactant phase and the water phase as a solution system for forming a silica gel precursor; 2) preparing a silica gel mixture obtained by uniformly mixing a gelling agent and silica sol, and dropwise adding the silica gel mixture into the solution system in the step 1), wherein the silica gel mixture shrinks into a spherical shape in an oil phase, passes through the oil phase and a surfactant phase, and reaches a water phase to obtain a silica gel precursor; and 3) extracting the oil phase and the surfactant phase, and aging the silicon gel precursor and the water phase at a certain temperature, and crystallizing at a certain temperature to obtain binder-free FAU type molecular sieve particles; wherein, the preparation of the silicon gel precursor and the subsequent aging and crystallization are carried out in the same reaction system.
According to the invention, the solution system for forming the silicone gel precursor is a three-phase system which sequentially comprises an oil phase, a surfactant phase and a water phase from top to bottom.
According to a preferred embodiment of the present invention, the oil phase is a single component of a hydrocarbon compound having a boiling point or a distillation range of 60 to 250 ℃ or a mixture thereof.
According to a preferred embodiment of the present invention, the hydrocarbon compound may be C5-C15 alkane, C5-C15 alkene or C5-C15 arene, preferably C5-C15 alkane, and more preferably C6-C10 alkane, and the single component or the mixture thereof.
According to a preferable scheme of the invention, the surfactant phase is a saturated surfactant aqueous solution with a hydrophilic-lipophilic balance value of 8-18.
According to a preferred embodiment of the invention, the saturated surfactant aqueous solution is a saturated aqueous solution of C12-C18 alkyl polymethacrylammonium halide.
According to a preferred embodiment of the present invention, the saturated aqueous surfactant solution is a saturated aqueous solution of cetyltrimethylammonium bromide.
According to a preferred embodiment of the present invention, both the oil phase and the surfactant phase can be recycled.
According to a preferred embodiment of the present invention, the alkaline solution in which the aluminum source is dissolved is an aqueous alkali metal hydroxide solution in which a soluble aluminum salt, aluminate or meta-aluminate is dissolved. More preferably, it is a sodium hydroxide solution in which meta-aluminate is dissolved.
According to a preferred embodiment of the present invention, the soluble aluminum salt may be Al2(SO4)3、Al(NO3)3And the like.
According to a preferred embodiment of the present invention, the soluble aluminate or meta-aluminate may be a soluble aluminate or meta-aluminate of K, Na, Mg, Ca, etc.
According to a preferable embodiment of the present invention, the molar ratio of the soluble aluminum salt, aluminate or meta-aluminate to the alkali metal hydroxide in the alkaline solution dissolved with the aluminum source is 1:1 to 1:10, preferably 1:2 to 1: 6.
According to a preferred embodiment of the present invention, the concentration of the soluble aluminum salt, aluminate or meta-aluminate dissolved in the alkaline solution containing an aluminum source is 1 to 50%, preferably 5 to 30%.
According to a preferable embodiment of the present invention, the volume ratio of the oil phase to the water phase is 10:1 to 1:50, preferably 1:1 to 1:30, and more preferably 1:2 to 1: 20.
According to a preferable embodiment of the present invention, the volume ratio of the surfactant phase to the aqueous phase is 1:10 to 1:100, preferably 1:10 to 1:60, and more preferably 1:10 to 1: 40.
According to a preferred embodiment of the present invention, the silica sol is an aqueous solution of uniformly dispersed silica nanoparticles, and may also be an alkali metal or alkaline earth metal soluble silicate.
According to a preferred embodiment of the present invention, the silica sol is an aqueous solution of uniformly dispersed silica nanoparticles, and the aqueous solution further has one or both of the following characteristics:
(1) the content of silica is 5 to 60%, preferably 10 to 50%, more preferably 20 to 40%, based on the weight of the silica sol;
(2) the particle size of the silica nanoparticles is 5 to 150nm, preferably 10 to 100nm, and more preferably 10 to 60 nm.
According to a preferred embodiment of the present invention, the silica sol solution containing the gelling agent is prepared by: the gel is prepared by fully stirring a proper amount of gelling agent aqueous solution and silica sol.
According to a preferred embodiment of the present invention, the silica sol gelling agent is a single substance or a mixture of a nitrogen-containing compound or an organic amine compound.
According to a preferred embodiment of the present invention, the nitrogen-containing compound may be a single substance or a mixture of the following substances:
ammonium chloride, ammonium nitrate, ammonium bromide, ammonium fluoride, ammonium sulfate, ammonium bisulfate, ammonium sulfide, ammonium bisulfide, ammonium carbonate, ammonium bicarbonate.
According to a preferred embodiment of the present invention, the organic amine compound may be a single substance or a mixture of the following substances: hexamethylenetetramine and its derivatives.
According to a preferred embodiment of the invention, the silica sol gelling agent is ammonium chloride.
According to a preferred embodiment of the present invention, the silica sol gelling agent is an aqueous solution of ammonium chloride with a certain concentration, and the mass fraction of the ammonium chloride is 1 to 30%, preferably 5 to 20%, and more preferably 5 to 15%.
According to a preferred embodiment of the present invention, the amount of the silica sol gelling agent is 1 to 50% (by mass), preferably 10 to 30%, of the silica sol.
According to a preferred scheme of the invention, the molar ratio of the raw materials is as follows: n (Al)2O3):n(SiO2):n(Na2O):n(H2O is (0.25 to 3.0):1, (0.1 to 3.0): 20 to 100, preferably n (Al)2O3):n(SiO2):n(Na2O):n(H2O) (0.25 to 1.0) 1 (1.0 to 2.0) and (30 to 80), and the raw material is represented in the form of an oxide.
According to a preferred embodiment of the invention, the ageing process has one or more of the following characteristics:
the temperature in the aging process is 10-80 ℃, preferably 15-60 ℃, and more preferably 20-50 ℃;
the aging time is 1-120 h, preferably 3-72 h, more preferably 3-30 h;
according to a preferred embodiment of the invention, the crystallization process has one or more of the following characteristics:
the temperature in the crystallization process is 60-200 ℃, preferably 60-160 ℃, more preferably 80-150 ℃;
the time of the crystallization process is 1 to 96 hours, preferably 3 to 72 hours, and more preferably 3 to 48 hours.
According to a preferred embodiment of the present invention, after the crystallization is finished, the obtained mixture is further processed as follows: the mixture was filtered and washed several times with deionized water, and the solid was collected and dried.
According to a preferred embodiment of the present invention, the drying temperature is 40 to 200 ℃, preferably 60 to 180 ℃, and more preferably 60 to 150 ℃.
According to a preferred embodiment of the present invention, the drying time is 1 to 120 hours, preferably 2 to 72 hours, and more preferably 2 to 48 hours.
According to a preferred embodiment of the present invention, after crystallization is completed, the mixture is filtered to obtain a crystallization mother liquor, and a certain amount of aluminum salt, aluminate or meta-aluminate and alkali metal hydroxide are added again, so that the crystallization mother liquor can be reused.
According to a preferred embodiment of the present invention, the preparation method further comprises the steps of: 4) and carrying out ion exchange on the prepared FAU type molecular sieve particles without the binding agent to obtain corresponding modified FAU type molecular sieve particles without the binding agent.
According to a preferred embodiment of the invention, the unmodified binderless FAU type molecular sieveThe metal ion contained in the particles is Na+。
According to a preferred embodiment of the present invention, the step 4) of ion exchange modification of the binderless FAU type molecular sieve particles should be preceded by the step 3). And (2) placing the prepared adhesive-free FAU type molecular sieve particles into other metal ion solutions with certain concentration, fully stirring for a certain time, washing with deionized water, and roasting to obtain the adhesive-free FAU type molecular sieve particles modified by the metal ions, wherein the metal in the metal ion solutions is different from the metal in the alkaline solution dissolved with an aluminum source.
According to a preferred embodiment of the present invention, the metal ion in the ion-modified binderless FAU-type molecular sieve particles is Na+、Ag+、Ni2+、Ca2+、Mg2+、Zn2+、Cu2+And Co2+One or more ions of (1), preferably Ni2+、Ca2 +、Mg2+、Zn2+、Cu2+And Co2+One or more ions.
According to a preferred embodiment of the present invention, the binder-free FAU-type molecular sieve particles modified with the target ion should have a higher adsorption capacity than the original unmodified molecular sieve.
According to a preferred embodiment of the present invention, the metal ion solution may be an aqueous solution of soluble salts of group IA or group IIA metals, or one or more metals selected from group VIII, group IB, group IIB, or group VIB metals.
According to a preferred embodiment of the present invention, the metal ions contained in the modified binderless FAU type molecular sieve particles may be group IA or group IIA metals, or may be one or more ions of group VIII, group IB, group IIB, or group VIB metals.
According to a preferred embodiment of the invention, the metal ion solution is a corresponding aqueous nitrate solution.
According to a preferred embodiment of the present invention, the concentration of the metal ion solution is 0.01 to 10mol/L, preferably 0.1 to 1mol/L, and more preferably 0.2 to 1 mol/L.
According to a preferred embodiment of the present invention, in the ion exchange modification process, the mass ratio of the binder-free FAU-type molecular sieve particles to the metal ion solution is 1:5 to 1:50, preferably 1:5 to 1:25, and more preferably 1:10 to 1: 20.
According to a preferred embodiment of the present invention, the temperature of the exchange is 25 to 150 ℃, preferably 25 to 100 ℃, and more preferably 25 to 80 ℃.
According to a preferred embodiment of the present invention, the time for the exchange is 1 to 72 hours, preferably 3 to 48 hours, and more preferably 3 to 24 hours.
According to a preferred embodiment of the present invention, the binderless FAU type molecular sieve particles or the modified binderless FAU type molecular sieve particles are activated by high temperature calcination before use.
According to a preferred embodiment of the present invention, the temperature of the calcination is 200 to 800 ℃, preferably 250 to 600 ℃, and more preferably 300 to 550 ℃.
According to a preferred embodiment of the present invention, the roasting time is 1 to 72 hours, preferably 1 to 48 hours, and more preferably 2 to 24 hours.
According to a preferred embodiment of the present invention, the binder-free FAU molecular sieve has a particle size of about 0.5 to 5 mm.
According to a second aspect of the present invention, there is also provided a binderless FAU-type molecular sieve particle produced according to the above-described method of preparation.
The binderless FAU-type molecular sieve particles prepared according to the present invention have one or more of the following characteristics:
1) the pore volume of the micropores is 0.10-0.35 cm3/g；
2) The average pore diameter of the micropores is 0.2-2 nm;
3) the specific surface area is 300-650 m2/g；
4) The ratio of silicon to aluminum in the framework [ n (Si)/n (A1) ] is 1-3;
5) mechanical strength > 20N.
Wherein 1) micropore volume, 2) micropore average pore diameter and 3) specific surface area are different from FAU type molecular sieve particles prepared by the prior art.
According to a third aspect of the invention, there is also provided a use of binderless FAU-type molecular sieve particles, said use comprising the fields of adsorption, separation, ion exchange and catalysis.
Oil phase
The oil phase is a single component of hydrocarbon compounds with boiling points or distillation ranges of 60-250 ℃ or a mixture of the single component and the mixture. The hydrocarbon compound can be C5-C15 alkane, C5-C15 alkene or C5-C15 arene, preferably single component or mixture of C5-C15 alkane, more preferably single component or mixture of C6-C10 alkane.
Aqueous phase
The water phase of the invention is an alkaline solution dissolved with an aluminum source. The alkaline solution in which the aluminum source is dissolved is an aqueous alkali metal hydroxide solution in which a soluble aluminum salt, aluminate or meta-aluminate is dissolved. The soluble aluminum salt may be Al2(SO4)3、Al(NO3)3And the like. The soluble aluminate or meta-aluminate can be K, Na, Mg, Ca and other soluble aluminates or meta-aluminates. More preferably, it is a sodium hydroxide solution in which meta-aluminate is dissolved.
Surfactant phase
The surfactant phase is a saturated surfactant aqueous solution with a hydrophilic-lipophilic balance value of 8-18. The saturated surfactant aqueous solution is a saturated aqueous solution of C12-C18 alkyl polymethyl ammonium halide. More preferably, it is a saturated aqueous solution of CTAB (cetyltrimethylammonium bromide).
Silica sol
The silica sol is a uniformly dispersed silicon dioxide nano particle aqueous solution.
In another preferred embodiment, the silica sol is a uniformly dispersed aqueous solution of silica nanoparticles, and the aqueous solution further has one or two of the following characteristics:
(1) the content of silica is 5 to 60%, preferably 10 to 50%, more preferably 20 to 40%, based on the weight of the silica sol;
(2) the particle size of the silica nanoparticles is 5 to 150nm, preferably 10 to 100nm, and more preferably 10 to 60 nm.
Gelling agent
The silica sol gelling agent of the present invention is a single substance or a mixture of a nitrogen-containing compound or an organic amine compound.
The nitrogen-containing compound may be a single species or a mixture of the following:
ammonium chloride, ammonium nitrate, ammonium bromide, ammonium fluoride, ammonium sulfate, ammonium bisulfate, ammonium sulfide, ammonium bisulfide, ammonium carbonate, ammonium bicarbonate.
The organic amine compound may be a single species or a mixture thereof of:
hexamethylenetetramine and its derivatives.
The oil phase and the surfactant phase involved in the preparation process of the FAU type molecular sieve particle without the binding agent can be recycled. In addition, after the crystallization is finished, a certain amount of aluminum salt, aluminate or meta-aluminate and alkali metal hydroxide are added into the crystallization mother liquor obtained after the mixture is filtered, and the crystallization mother liquor can be repeatedly used.
The metal ions contained in the binderless FAU-type molecular sieve particles can be group IA or group IIA metals, and can also be one or more ions of group VIII, group IB, group IIB or group VIB metals. Different purposes of adsorption separation, catalysis, ion exchange and the like can be realized through the FAU type molecular sieve particles without the binding agent modified by different metal ions. The ion exchange modification can change the selective adsorption, catalytic reaction, ion exchange and other performances of the binderless FAU type molecular sieve particles on specific substances by changing the pore structure, the specific surface area and the interaction with adsorbate molecules of the binderless FAU type molecular sieve particles.
The inventors have made extensive and intensive studies and, for the first time, have unexpectedly found a method for producing binder-free FAU-type molecular sieve particles. Compared with the traditional preparation method of the binderless molecular sieve particles, the preparation method can synthesize the binderless FAU type molecular sieve particles by one step of in-situ hydrothermal conversion of the silica sol precursor, thereby effectively simplifying the experimental steps, shortening the experimental flow and avoiding the problem of environmental pollution caused by high-temperature hot oil. The FAU molecular sieve particles without the binder prepared by the invention have larger specific surface area and larger hexene adsorption capacity than the commercial FAU type molecular sieve particles containing the binder. Meanwhile, the FAU molecular sieve particles without the binder prepared by the invention have the advantages of available high absorption/desorption rate, high adsorption selectivity and excellent anti-coking performance compared with FAU type molecular sieve particles with the binder. Finally, the FAU molecular sieve particles without the binding agent prepared by the invention can greatly improve the service performance of the FAU molecular sieve in the adsorption separation, catalysis and cation exchange industries.
According to the FAU type molecular sieve particles without the binder and the preparation method and the application thereof, compared with the prior art, the FAU type molecular sieve particles without the binder have the following advantages:
(1) the FAU type molecular sieve particle without the binding agent can be synthesized by one step through in-situ hydrothermal conversion of a silica sol precursor, the raw materials are cheap and easy to obtain, the experimental method is simple, and the related process flow is effectively simplified.
(2) The silica gel precursor is prepared at normal temperature, so that the pollution of high-temperature hot oil to the environment is effectively reduced; the water phase, the surfactant phase and the oil phase involved in the synthesis process can be recycled, so that the pollution of the raw material discharge to the environment is reduced.
(3) Compared with the commercial adhesive products, the FAU molecular sieve particles without the adhesive synthesized by the invention have the advantages of large adsorption capacity, high adsorption rate, high mechanical strength, low coking rate and the like, can be widely applied to industrial production, and greatly improves the application prospect of the FAU molecular sieve in the adsorption separation, catalysis and ion exchange industries.
(4) Based on the method provided by the invention, other types of binderless molecular sieve particles, such as MFI, BEA, MOR and the like, can be easily prepared by changing the initial reaction species and the proportion thereof and adjusting the aging and crystallization reaction conditions.
(5) Based on the method provided by the invention, the binderless FAU type molecular sieve particles with hierarchical pores or other types of binderless molecular sieve particles with hierarchical pores can be prepared by adding the organic additive.
Drawings
Fig. 1 is an XRD spectrum of binder-free FAU-type molecular sieve particles prepared in examples 1, 2, 3 and 4 of the present invention, wherein a, b, c and d are XRD spectra of examples 1, 2, 3 and 4, respectively;
fig. 2 is SEM pictures of binder-free FAU-type molecular sieve particles prepared in examples 1, 2, 3 and 4 of the present invention, wherein a, b, c and d are SEM pictures of examples 1, 2, 3 and 4, respectively;
fig. 3 is an XRD spectrum of different metal ion modified binderless FAU-type molecular sieve particles prepared in example 5 of this invention with unmodified product (NaX);
fig. 4 is a graph showing the gas phase adsorption amounts of different metal ion modified binderless FAU-type molecular sieve particles and unmodified product (NaX) prepared in example 5 of the present invention.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out under conventional conditions or conditions recommended by the manufacturers. Unless otherwise indicated, percentages and parts are percentages and parts by weight.
The test materials and reagents used in the following examples are commercially available without specific reference.
Example 1
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 12.3 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 20 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) to the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
weighing 23.5 parts of silica sol (40 wt.%, the particle size of the silica nanoparticles is about 20nm) and 5 parts of ammonium chloride solution (10 wt.%), rapidly and uniformly stirring to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution system to obtain a silica gel precursor. After the upper oil phase and the surfactant phase in the middle layer are pumped away and recovered, the water phase and the silica gel precursor are transferred to a crystallization kettle, aged for 6 hours at 40 ℃ and crystallized for 24 hours at 100 ℃. And after crystallization is finished, filtering the mixture, recovering aqueous phase alkali liquor, washing the solid for several times by using deionized water, collecting the solid, drying at 100 ℃ for 6 hours to obtain binder-free FAU type molecular sieve particles, degassing at 300 ℃ for 6 hours, and determining the hexene gas phase adsorption quantity of the particles. The XRD pattern and SEM image of the FAU type molecular sieve prepared in this example are shown as a in FIG. 1, the mechanical strength of the particles is 20N, and the gas phase adsorption amount is 178.2 mg-hexene/g-molecular sieve (25 ℃, P/P)0＝0.85)。
Example 2
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 16.4 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 20 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) to the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
weighing 23.5 parts of silica sol (40 wt.%, the particle size of the silica nanoparticles is about 20nm) and 5 parts of ammonium chloride solution (10 wt.%), rapidly and uniformly stirring to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution system to obtain a silica gel precursor. Withdrawing and recovering the upper oil phase andafter the surfactant phase of the middle layer, the water phase and the silicon dioxide gel precursor are transferred to a crystallization kettle, and are aged for 6 hours at 40 ℃ and then crystallized for 24 hours at 100 ℃. And after crystallization is finished, filtering the mixture, recovering aqueous phase alkali liquor, washing the solid for several times by using deionized water, collecting the solid, drying at 100 ℃ for 6 hours to obtain binder-free FAU type molecular sieve particles, degassing at 300 ℃ for 6 hours, and determining the hexene gas phase adsorption quantity of the particles. The XRD pattern and SEM image of the FAU-type molecular sieve prepared in this example are shown as b in FIG. 1 and b in FIG. 2, the mechanical strength of the particles is 18N, and the gas phase adsorption capacity is 38.6 mg-hexene/g-molecular sieve (25 ℃, P/P)0＝0.85)。
Example 3
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 12.3 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 20 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) to the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
weighing 23.5 parts of silica sol (40 wt.%, the particle size of the silica nanoparticles is about 20nm) and 5 parts of ammonium chloride solution (10 wt.%), rapidly and uniformly stirring to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution system to obtain a silica gel precursor. After the upper oil phase and the surfactant phase in the middle layer are pumped away and recovered, the water phase and the silica gel precursor are transferred to a crystallization kettle, and are aged for 6 hours at 40 ℃ and then crystallized for 24 hours at 110 ℃. And after crystallization is finished, filtering the mixture, recovering aqueous phase alkali liquor, washing the solid for several times by using deionized water, collecting the solid, drying at 100 ℃ for 6 hours to obtain binder-free FAU type molecular sieve particles, degassing at 300 ℃ for 6 hours, and determining the hexene gas phase adsorption quantity of the particles. The XRD spectrum and SEM picture of the FAU type molecular sieve prepared in this example are shown as c in FIG. 1As shown in c in FIG. 2, the mechanical strength of the pellets was 15N, and the gas phase adsorption amount was 171.2 mg-hexene/g-molecular sieve (25 ℃ C., P/P)0＝0.85)。
Example 4
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 12.3 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 20 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) to the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
weighing 23.5 parts of silica sol (40 wt.%, the particle size of the silica nanoparticles is about 20nm) and 5 parts of ammonium chloride solution (10 wt.%), rapidly and uniformly stirring to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution to obtain a silica gel precursor. After the upper oil phase and the surfactant phase in the middle layer are pumped away and recovered, the water phase and the silicon dioxide gel precursor are transferred to a crystallization kettle, aged for 6 hours at 40 ℃ and crystallized for 36 hours at 100 ℃. And after crystallization is finished, filtering the mixture, recovering aqueous phase alkali liquor, washing the solid for several times by using deionized water, collecting the solid, drying at 100 ℃ for 6 hours to obtain binder-free FAU type molecular sieve particles, degassing at 300 ℃ for 6 hours, and determining the hexene gas phase adsorption quantity of the particles. The XRD pattern and SEM image of the FAU-type molecular sieve prepared in this example are shown as d in FIG. 1, the mechanical strength of the particles is 17N, and the gas phase adsorption amount is 112.5 mg-hexene/g-molecular sieve (25 ℃, P/P)0＝0.85)。
Example 5
7 batches of the binderless FAU type molecular sieve particles prepared in example 1, each 10 batches, were taken and placed in a beaker, to which 0.5mol/L Ca (NO) was added3)2、Ni(NO3)2、Mg(NO3)2、Zn(NO3)2、Cu(NO3)2、Co(NO3)2、AgNO 3200 parts of the solution. After stirring at 60 ℃ for 6h, it was washed several times with deionized water and dried. The XRD spectrum and the gas phase adsorption amount of the ion exchange sample were shown in fig. 3 and 4, respectively. From the results of the gas phase adsorption amount, it is preferable that Ca be used as the ion-modified component2+、Ni2 +、Mg2+、Zn2+、Cu2+And Co2+One or more ions.
Example 6
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 12.3 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 10 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) into the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
weighing 23.5 parts of silica sol (40 wt.%, the particle size of the silica nanoparticles is about 20nm) and 5 parts of ammonium chloride solution (10 wt.%), rapidly and uniformly stirring to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution system to obtain a silica gel precursor. After the upper oil phase and the surfactant phase in the middle layer are pumped away and recovered, the water phase and the silica gel precursor are transferred to a crystallization kettle, aged for 6 hours at 40 ℃ and crystallized for 24 hours at 100 ℃. And after crystallization is finished, filtering the mixture, recovering aqueous phase alkali liquor, washing the solid for several times by using deionized water, collecting the solid, drying at 100 ℃ for 6 hours to obtain binder-free FAU type molecular sieve particles, degassing at 300 ℃ for 6 hours, and determining the hexene gas phase adsorption quantity of the particles. The FAU type molecular sieve prepared in this example had a gas phase adsorption of 165.2 mg-hexene/g-molecular sieve (25 ℃, P/P)0＝0.85)。
Example 7
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 12.3 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 20 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) to the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
weighing 23.5 parts of silica sol (40 wt.%, the particle size of the silica nanoparticles is about 50nm) and 5 parts of ammonium chloride solution (10 wt.%), rapidly and uniformly stirring to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution system to obtain a silica gel precursor. After the upper oil phase and the surfactant phase in the middle layer are pumped away and recovered, the water phase and the silica gel precursor are transferred to a crystallization kettle, aged for 6 hours at 40 ℃ and crystallized for 24 hours at 100 ℃. And after crystallization is finished, filtering the mixture, recovering aqueous phase alkali liquor, washing the solid for several times by using deionized water, collecting the solid, drying at 100 ℃ for 6 hours to obtain binder-free FAU type molecular sieve particles, degassing at 300 ℃ for 6 hours, and determining the hexene gas phase adsorption quantity of the particles. The FAU type molecular sieve prepared in this example had a gas phase adsorption of 134.7 mg-hexene/g-molecular sieve (25 ℃, P/P)0＝0.85)。
Example 8
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 12.3 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 20 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) to the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
23.5 parts of silica sol (A) are weighed40 wt.%, the particle diameter of the silica nanoparticle is about 20nm) and 10 parts of ammonium chloride solution (10 wt.%), rapidly stirring uniformly to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution system to obtain a silica gel precursor. After the upper oil phase and the surfactant phase in the middle layer are pumped away and recovered, the water phase and the silica gel precursor are transferred to a crystallization kettle, aged for 6 hours at 40 ℃ and crystallized for 24 hours at 100 ℃. And after crystallization is finished, filtering the mixture, recovering aqueous phase alkali liquor, washing the solid for several times by using deionized water, collecting the solid, drying at 100 ℃ for 6 hours to obtain binder-free FAU type molecular sieve particles, degassing at 300 ℃ for 6 hours, and determining the hexene gas phase adsorption quantity of the particles. The FAU type molecular sieve prepared in this example had a gas phase adsorption of 111.7 mg-hexene/g-molecular sieve (25 ℃, P/P)0＝0.85)。
Example 9
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 12.3 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 20 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) to the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
weighing 23.5 parts of silica sol (40 wt.%, the particle size of the silica nanoparticles is about 20nm) and 5 parts of ammonium chloride solution (10 wt.%), rapidly and uniformly stirring to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution system to obtain a silica gel precursor. After the upper oil phase and the surfactant phase in the middle layer are pumped away and recovered, the water phase and the silica gel precursor are transferred to a crystallization kettle, aged for 6 hours at 40 ℃ and crystallized for 24 hours at 100 ℃. After crystallization is completed, the mixture is filtered, aqueous phase alkali liquor is recovered, the solid is washed for several times by deionized water, the solid is collected, anddrying at 100 deg.C for 6h to obtain binderless FAU type molecular sieve particles, degassing at 250 deg.C for 6h, and measuring its hexene gas phase adsorption amount. The FAU type molecular sieve prepared in this example had a gas phase adsorption of 171.5 mg-hexene/g-molecular sieve (25 ℃, P/P)0＝0.85)。
Example 10
Preparing an oil phase, a surfactant phase and a water phase three-phase system:
dissolving 12.3 parts of sodium metaaluminate and 12.0 parts of sodium hydroxide in 115.0 parts of deionized water, stirring to dissolve the sodium metaaluminate and the sodium hydroxide, carrying out suction filtration to obtain clear liquid (water phase), and then sequentially adding 20 parts of CTAB saturated aqueous solution (surfactant phase) and 40 parts of n-heptane (oil phase) to the upper part of the obtained clear liquid to form a three-phase system containing an oil phase, the surfactant phase and the water phase, wherein the three-phase system is used as a solution system for forming a silica gel precursor.
Preparing FAU type molecular sieve particles without a binder:
weighing 23.5 parts of silica sol (40 wt.%, the particle size of the silica nanoparticles is about 20nm) and 5 parts of ammonium chloride solution (10 wt.%), rapidly and uniformly stirring to obtain a silica gel mixture, and dropwise adding the gel mixture into the prepared forming solution system to obtain a silica gel precursor. After the upper oil phase and the surfactant phase in the middle layer are pumped away and recovered, the water phase and the silica gel precursor are transferred to a crystallization kettle, aged for 6 hours at 40 ℃ and crystallized for 24 hours at 100 ℃. And after crystallization is finished, filtering the mixture, recovering aqueous phase alkali liquor, washing the solid for several times by using deionized water, collecting the solid, drying at 100 ℃ for 6 hours to obtain binder-free FAU type molecular sieve particles, degassing at 300 ℃ for 12 hours, and then determining the hexene gas phase adsorption quantity of the particles. The FAU type molecular sieve prepared in this example had a gas phase adsorption of 178.1 mg-hexene/g-molecular sieve (25 ℃, P/P)00.85). The mechanical strength of the granules was 30N.
Experimental example 1
About 1 part of the binder-free FAU type molecular sieve particles to be measured after drying in example 1 was taken, and the hexene adsorption amount thereof was measured by a steam adsorber. Before testing, a degassing furnace of the instrument is used for degassing a sample to be tested at 300 ℃ for 6h,then measuring the hexene gas phase adsorption amount at 25 deg.C, wherein the hexene vapor pressure is 0.85 of the saturated vapor pressure of hexene at 25 deg.C, i.e. P/P00.85. The hexene gas phase adsorption was determined to be 178.2 mg-hexene/g-molecular sieve.
Experimental example 2
And a small fixed bed is adopted to further investigate the actual adsorption and separation effect of the prepared binder-free FAU type molecular sieve particles on hexene. About 1.2 parts of the binder-free FAU type molecular sieve particles to be tested after drying in example 1 are taken, cooled to room temperature in a dryer after roasting activation, filled into a fixed bed, the flow rate of a hexene-n-hexane binary solution (the mass fraction of hexene is about 5%) is controlled by a constant flow pump, and the content of hexene in the solution is analyzed by gas chromatography. The actual size of the fixed bed is 10mm in inner diameter and 200mm in height, the circulating water temperature is constant at 25 ℃, and the feeding flow rate of the pump is set to be 0.5 mL/min. By fitting the relevant adsorption penetration model, the Thomas rate constant K can be obtainedth＝0.0017mL/(min·mg)。
Experimental example 3
About 40 parts of the binder-free FAU type molecular sieve particles to be tested after being dried in the embodiment 1 are taken, are cooled to room temperature in a dryer after being roasted and activated, are filled in a fixed bed adsorber with the inner diameter of 30mm, are introduced with hexene/nitrogen mixed gas at the flow rate of 0.1L/min, and are adsorbed for 2 hours at the temperature of 400 ℃. The molecular sieve deactivation (percentage reduction in hexene adsorption by the deactivated molecular sieve compared to fresh molecular sieve at 25 ℃) was determined to be 27.6%.
Comparative example 1
About 1 part of FAU type molecular sieve particles with a commercially available binder was used, and its hexene adsorption amount was measured by a steam adsorption apparatus. Before the test, the sample to be tested was degassed at 300 ℃ for 6 hours using a degassing furnace equipped with the apparatus itself, and then its hexene gas phase adsorption amount was measured at 25 ℃ wherein the pressure of hexene vapor was 0.85 of the saturated vapor pressure of hexene at 25 ℃, i.e., P/P0 was 0.85. The FAU type molecular sieve particles with the commercial binder had a gas phase adsorption of 133.6 mg-hexene/g-molecular sieve, as determined.
As can be seen from comparison with the results of the gas phase adsorption amount in experimental example 1, the binderless FAU-type molecular sieve particles prepared by the present invention have a larger adsorption capacity for hexene.
Comparative example 2
A small fixed bed is adopted to further examine the actual adsorption and separation effect of the prepared FAU type molecular sieve particles with the adhesive on hexene. Taking about 1.2 parts of commercial FAU type molecular sieve particles with the binder to be tested after roasting, cooling the particles to room temperature in a drier after roasting activation, filling the particles into a fixed bed, controlling the flow rate of a hexene-n-hexane binary solution (the mass fraction of hexene is about 5%) by using a constant flow pump, and analyzing the content of hexene in the solution by using gas chromatography. The actual size of the fixed bed is 10mm in inner diameter and 200mm in height, the circulating water temperature is constant at 25 ℃, and the feeding flow rate of the pump is set to be 0.5 mL/min. By fitting the relevant adsorption penetration model, the Thomas rate constant K can be obtainedth＝0.0011mL/(min·mg)。
As can be seen from comparison with the adsorption breakthrough results in experimental example 2, the binderless FAU-type molecular sieve particles prepared by the present invention have a larger thomas rate constant.
Comparative example 3
Taking about 40 parts of dried FAU type molecular sieve particles to be detected, which are sold with the adhesive and are to be detected, cooling the particles to room temperature in a dryer after roasting and activating, filling the particles into a fixed bed adsorber with the inner diameter of 30mm, introducing hexene/nitrogen mixed gas at the flow rate of 0.1L/min, and adsorbing the mixture for 2 hours at the temperature of 400 ℃. The molecular sieve deactivation (percentage reduction in hexene adsorption by the deactivated molecular sieve compared to fresh molecular sieve at 25 ℃) was determined to be 42.7%.
Compared with the inactivation degree result in the experimental example 3, the FAU type molecular sieve particles without the binder prepared by the invention have better anti-coking performance.
The method adopts a one-pot synthesis method, the binder-free FAU type molecular sieve particles can be synthesized by one step through in-situ hydrothermal conversion of the silica sol precursor, the raw materials are cheap and easy to obtain, the experimental method is simple, and the related process flow is effectively simplified; the related silica gel precursor is prepared at normal temperature, so that the pollution of high-temperature hot oil to the environment is effectively reduced; the water phase, the surfactant phase and the oil phase involved in the synthesis process can be recycled, so that the pollution of the discharge of raw materials to the environment is reduced; and the synthesized molecular sieve particles have the advantages of large adsorption capacity, high adsorption rate, high mechanical strength, low coking rate and the like, can be widely applied to industrial production, and greatly improves the application prospect of the FAU type molecular sieve in the adsorption separation, catalysis and ion exchange industries.
According to the method provided by the invention, other types of binderless molecular sieve particles, such as MFI, BEA, MOR and the like, can also be prepared by changing the feeding proportion, the ageing and the crystallization conditions. In addition, based on the method provided by the invention, the binderless FAU type molecular sieve particles with hierarchical pores or other types of binderless molecular sieve particles with hierarchical pores can be prepared by adding the organic additive.
The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.
Claims (10)
1. A preparation method of binder-free FAU type molecular sieve particles is characterized by comprising the following steps:
1) taking an alkaline solution dissolved with an aluminum source as a water phase, and sequentially adding a surfactant aqueous solution and an oil phase on the alkaline solution to form a three-phase system containing an oil phase, a surfactant phase and the water phase as a solution system for forming a silica gel precursor;
2) providing a silica gel mixture obtained by uniformly mixing a gelling agent and silica sol, dropwise adding the silica gel mixture into the solution system prepared in the step 1), enabling the silica gel mixture to enter an oil phase and shrink into a spherical shape in the oil phase, and enabling the silica gel mixture to pass through the oil phase and a surfactant phase to reach a water phase to obtain a silica gel precursor; and
3) removing the oil phase and the surfactant phase, aging the silicon gel precursor and the water phase at a certain temperature, and crystallizing at a certain temperature to obtain binder-free FAU type molecular sieve particles;
wherein, the preparation of the silicon gel precursor and the subsequent aging and crystallization are carried out in the same reaction system.
2. The production method according to claim 1, wherein the alkali solution in which the aluminum source is dissolved is an aqueous alkali metal hydroxide solution in which a soluble aluminum salt, aluminate or meta-aluminate is dissolved.
3. The preparation method according to claim 1, wherein the surfactant phase is a saturated surfactant aqueous solution with a hydrophilic-lipophilic balance value of 8-18.
4. The method according to claim 1, wherein the oil phase is a single component of a hydrocarbon compound having a boiling point or a boiling range of 60 to 250 ℃ or a mixture thereof.
5. The method according to claim 1, wherein the oil phase is added in an amount of 1 to 5 times the volume of the surfactant phase.
6. The method according to claim 1, wherein the experimental conditions for aging and crystallization are as follows:
the aging temperature is 10-80 ℃, preferably 15-60 ℃, and more preferably 20-50 ℃;
the aging time is 1-120 h, preferably 3-72 h, more preferably 3-30 h;
the crystallization temperature is 60-200 ℃, preferably 60-160 ℃, and more preferably 80-150 ℃;
the crystallization time is 1 to 96 hours, preferably 3 to 72 hours, and more preferably 3 to 48 hours.
7. The method of claim 1, further comprising the steps of:
4) and carrying out ion exchange on the prepared FAU type molecular sieve particles without the binding agent to obtain corresponding modified FAU type molecular sieve particles without the binding agent.
8. The method for preparing according to claim 7, wherein the step 4) includes: and (2) placing the prepared adhesive-free FAU type molecular sieve particles into a metal ion solution with a certain concentration, fully stirring for a certain time, washing with deionized water, and roasting to obtain the modified adhesive-free FAU type molecular sieve particles containing the metal ions, wherein the metal in the metal ion solution is different from the metal in the alkaline solution dissolved with an aluminum source.
9. A binderless FAU-type molecular sieve particle produced by the process of any one of claims 1 to 8.
10. Use of the binderless FAU-type molecular sieve particles of claim 9 in applications comprising adsorption, separation, ion exchange and catalysis.
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