CN109502603B - Preparation method of magnetic molecular sieve and obtained magnetic molecular sieve - Google Patents
Preparation method of magnetic molecular sieve and obtained magnetic molecular sieve Download PDFInfo
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- 239000002808 molecular sieve Substances 0.000 title claims abstract description 243
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 title claims abstract description 242
- 238000002360 preparation method Methods 0.000 title abstract description 7
- 238000000034 method Methods 0.000 claims abstract description 45
- 150000003863 ammonium salts Chemical class 0.000 claims abstract description 30
- 238000005342 ion exchange Methods 0.000 claims abstract description 24
- 239000012298 atmosphere Substances 0.000 claims description 40
- 239000012266 salt solution Substances 0.000 claims description 36
- 239000012299 nitrogen atmosphere Substances 0.000 claims description 30
- 238000001035 drying Methods 0.000 claims description 29
- 239000000243 solution Substances 0.000 claims description 29
- 239000001257 hydrogen Substances 0.000 claims description 26
- 229910052739 hydrogen Inorganic materials 0.000 claims description 26
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 25
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 24
- 238000001354 calcination Methods 0.000 claims description 22
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 21
- 230000004048 modification Effects 0.000 claims description 21
- 238000012986 modification Methods 0.000 claims description 21
- 239000001301 oxygen Substances 0.000 claims description 21
- 229910052760 oxygen Inorganic materials 0.000 claims description 21
- 238000006243 chemical reaction Methods 0.000 claims description 15
- USFZMSVCRYTOJT-UHFFFAOYSA-N Ammonium acetate Chemical group N.CC(O)=O USFZMSVCRYTOJT-UHFFFAOYSA-N 0.000 claims description 13
- 239000005695 Ammonium acetate Substances 0.000 claims description 13
- 229940043376 ammonium acetate Drugs 0.000 claims description 13
- 235000019257 ammonium acetate Nutrition 0.000 claims description 13
- 238000010304 firing Methods 0.000 claims description 13
- 150000002505 iron Chemical class 0.000 claims description 13
- 229910052757 nitrogen Inorganic materials 0.000 claims description 13
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 claims description 12
- -1 amine chloride Chemical class 0.000 claims description 11
- 238000000926 separation method Methods 0.000 claims description 10
- 230000003213 activating effect Effects 0.000 claims description 8
- 230000004913 activation Effects 0.000 claims description 7
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 4
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 4
- 238000000967 suction filtration Methods 0.000 claims description 3
- 239000002245 particle Substances 0.000 abstract description 28
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 abstract description 27
- 229910052665 sodalite Inorganic materials 0.000 abstract description 18
- 230000000694 effects Effects 0.000 abstract description 5
- 238000009776 industrial production Methods 0.000 abstract description 2
- 150000003839 salts Chemical class 0.000 abstract 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 99
- 230000005415 magnetization Effects 0.000 description 12
- 238000001914 filtration Methods 0.000 description 10
- 238000005406 washing Methods 0.000 description 10
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 9
- 239000013078 crystal Substances 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- 230000005389 magnetism Effects 0.000 description 6
- 230000005012 migration Effects 0.000 description 6
- 238000013508 migration Methods 0.000 description 6
- 238000006011 modification reaction Methods 0.000 description 5
- 229910052596 spinel Inorganic materials 0.000 description 5
- 239000011029 spinel Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000002441 X-ray diffraction Methods 0.000 description 4
- 229910021536 Zeolite Inorganic materials 0.000 description 4
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 239000010457 zeolite Substances 0.000 description 4
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000006555 catalytic reaction Methods 0.000 description 3
- 238000012512 characterization method Methods 0.000 description 3
- PVFSDGKDKFSOTB-UHFFFAOYSA-K iron(3+);triacetate Chemical compound [Fe+3].CC([O-])=O.CC([O-])=O.CC([O-])=O PVFSDGKDKFSOTB-UHFFFAOYSA-K 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 0.000 description 2
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 2
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 2
- 239000006249 magnetic particle Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000004065 wastewater treatment Methods 0.000 description 2
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 description 1
- 229910000358 iron sulfate Inorganic materials 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002082 metal nanoparticle Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000012716 precipitator Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000001959 radiotherapy Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000012279 sodium borohydride Substances 0.000 description 1
- 229910000033 sodium borohydride Inorganic materials 0.000 description 1
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- 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
- C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
- C01B39/20—Faujasite type, e.g. type X or Y
- C01B39/24—Type Y
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
- C01G49/08—Ferroso-ferric oxide [Fe3O4]
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/42—Magnetic properties
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Catalysts (AREA)
Abstract
The invention discloses a preparation method of a magnetic molecular sieve and the obtained magnetic molecular sieve, wherein the methodThe following were used: respectively adopting ammonium salt and ferric salt to sequentially perform ion exchange with the NaY type molecular sieve, and then performing post-treatment such as three-section roasting to obtain Fe3O4-a molecular sieve of the Fe/Y type, i.e. said magnetic molecular sieve. In the magnetic molecular sieve, Fe3O4The particles and the Fe particles are positioned in a sodalite cage of the molecular sieve, and the obtained magnetic molecular sieve has high Curie temperature and good magnetic property. The method is simple, easy to realize, mild in operation condition, green and environment-friendly, and suitable for industrial production and application; the magnetic molecular sieve has stable structure and is not easy to lose Fe in the using process3O4And/or Fe, so that the service life is long, the effect is good, and the magnetic molecular sieve can be recycled.
Description
Technical Field
The invention relates to the field of molecular sieves, in particular to a magnetic molecular sieve, and particularly relates to a preparation method of the magnetic molecular sieve and the obtained magnetic molecular sieve.
Background
The molecular sieve has a uniform microporous structure and good adsorption and ion exchange catalytic properties, so that the molecular sieve is widely applied to many fields. However, the pure zeolite molecular sieve has small density and fine powder, which is often nano or micron powder, and has excellent use effect after being modified.
The unique structure and properties of the molecular sieve enable the molecular sieve to be widely applied. Regardless of whether it is used as a catalyst or an adsorbent, rapid solid-liquid separation is required in each operation unit of catalysis and adsorption, but it is difficult to rapidly and efficiently separate the molecular sieve from the mother liquor by using the conventional separation technique.
From the beginning of the 20 th century, magnetic support technology (MCT) appeared in industrial catalysis in various forms, which is cheap and efficient. At present, the MCT technology is widely applied to complex processes such as biological medicine, radiotherapy, wastewater treatment, industrial catalysis, mineral processing and the like, and has great application prospects in the fields.
The essence of the magnetic carrier technology is that through different preparation processes, substances with strong magnetism are uniformly dispersed into the interior or on the surface of substances with weak magnetism or no magnetism and special functions, so that the substances can be separated from a system under the action of an external magnetic field. MCT was first proposed by Uthain in the 20 th century, 40 s when studying wastewater treatment, and it overcomes many of the limitations of traditional separation techniques.
And the MCT technology is utilized to transform the molecular sieve, so that the magnetism of the molecular sieve is increased, and the stability of the molecular sieve is also increased.
At present, the synthesis of the magnetic molecular sieve mainly comprises the following synthesis ideas:
(1) and modifying the surface of the molecular sieve by adopting magnetic metal nano particles. The method introduces metal ions to the surface of a molecular sieve by an impregnation method, and then reduces the metal ions into a simple substance by using a reducing agent such as hydrogen or sodium borohydride and the like. Although the method is simple, convenient and quick, the magnetic particles are easy to fall off on the surface, so that the material is easy to lose magnetism;
(2) the surface of the molecular sieve is modified by magnetic metal oxide. Dispersing a molecular sieve in a magnetic metal ion solution, and then adding a precipitator or directly roasting to form a magnetic metal oxide on the surface of the molecular sieve. This also tends to cause the shedding of magnetic particles;
(3) and (3) bonding the molecular sieve and the magnetic substance by using an adhesive method. Although the magnetic saturation strength is high, the stability is poor, and the adhesive fails along with the failure of the adhesive;
(4) magnetic materials are introduced into a synthesis system of the molecular sieve, so that the magnetic molecular sieve is synthesized. The method has the advantages of low energy consumption, strong operability and the like, but the method is easy to influence the structure and the adsorption capacity of the molecular sieve and is unfavorable for later application.
Disclosure of Invention
In order to overcome the above problems, the present inventors have conducted intensive studies by first obtaining the magnetic molecular sieve by two ion exchanges and then three-stage calcination, thereby completing the present invention.
One of the objectives of the present invention is to provide a method for preparing a magnetic molecular sieve, which is embodied in the following aspects:
(1) a method for preparing a magnetic molecular sieve, comprising the steps of:
step 2, carrying out ion exchange on the HY molecular sieve obtained in the step 1 and a soluble iron salt solution;
and 3, carrying out post-treatment to obtain the magnetic molecular sieve.
(2) The method according to the above (1), characterized in that step 1' is performed before step 1:
step 1', activating a molecular sieve;
preferably, the activation treatment is performed at 400-600 ℃, more preferably, the activation treatment is performed at 550 ℃, for example, 500 ℃;
and/or
step 1-1, adding a molecular sieve into an ammonium salt solution for modification;
and step 1-2, after the modification is finished, carrying out suction filtration, drying and roasting to obtain the HY type molecular sieve.
(3) The method according to the above (1) or (2), characterized in that, in step 1-1,
the ammonium salt is selected from ammonium acetate and/or amine halides, preferably the ammonium salt is selected from ammonium acetate and/or amine chloride, more preferably the ammonium salt is selected from ammonium acetate; and/or
The concentration of the ammonium salt solution is 0.1-0.5 mol/L, preferably 0.1-0.3 mol/L, and more preferably 0.2 mol/L; and/or
The ratio of the weight of the molecular sieve to the volume of the ammonium salt solution is 1 (20-80), preferably 1 (40-60), more preferably 1 (45-55), such as 1: 50; and/or
The modification was carried out as follows: the reaction is carried out at 60-120 ℃ for 12-24 h, preferably at 80-100 ℃ for 18-24 h, and more preferably at 90 ℃ for 22-24 h.
(4) The method according to one of the above (1) to (3), characterized in that, in step 1-2,
the drying is carried out at 80-140 ℃, preferably at 100-120 ℃; and/or
The roasting is carried out at 200-800 ℃, preferably at 300-700 ℃, and more preferably at 400-600 ℃.
(5) The method according to one of the above (1) to (4), characterized in that, in step 2,
the soluble ferric salt solution comprises a ferric chloride solution, a ferric sulfate solution, a ferric nitrate solution and an ferric acetate solution, preferably, the soluble ferric salt solution comprises a ferric chloride solution and a ferric nitrate solution, and more preferably, the soluble ferric salt solution is a ferric nitrate solution; and/or
The weight ratio of the HY type molecular sieve to the volume of the soluble iron salt solution is 1 (20-80), preferably 1 (40-60), more preferably 1 (45-55), such as 1: 50; and/or
The ion exchange is carried out as follows: the reaction is carried out at 60-120 ℃ for 8-30 h, preferably at 80-100 ℃ for 12-24 h, and more preferably at 90 ℃ for 24 h.
(6) The method according to one of the above (1) to (5), characterized in that, in step 3, the post-treatment comprises separation, drying and baking;
preferably, the drying is carried out as follows: drying in air and/or nitrogen at 80-140 ℃ for 4-18 h, preferably in air and/or nitrogen at 100-120 ℃ for 6-15 h;
(7) the method according to the above (6), characterized in that the roasting is three-stage roasting, wherein the atmosphere of roasting is nitrogen, oxygen and hydrogen in sequence;
preferably: the roasting is carried out at 300-700 ℃, preferably at 400-600 ℃, and more preferably at 450-550 ℃;
more preferably: the roasting is carried out for 4-20 h, preferably 8-15 h, for example 10 h.
(8) The method according to the above (7), wherein the firing is performed in the following order: roasting for 2-8 h in a nitrogen atmosphere, roasting for 2-8 h in an oxygen atmosphere, and roasting for 1-5 h in a hydrogen atmosphere; preferably, roasting for 4-6 h in a nitrogen atmosphere, roasting for 4-6 h in an oxygen atmosphere, and roasting for 2-4 h in a hydrogen atmosphere; more preferably, the calcination is carried out for 4 hours in a nitrogen atmosphere, for 4 hours in an oxygen atmosphere, and for 2 hours in a hydrogen atmosphere.
In a second aspect, the present invention provides a magnetic molecular sieve, which is embodied in the following aspects:
(9) a magnetic molecular sieve, preferably obtained by the method of any one of (1) to (8), wherein the molecular sieve is Fe3O4-Fe/Y type molecular sieves in which Fe is formed in situ within the Y molecular sieve3O4Particles and Fe particles;
preferably, the Fe3O4The particles are of spinel structure, the Fe particles are of body-centered cubic structure, and the Fe3O4The particles and the Fe particles are nano-scale;
more preferably, the Fe3O4The particles and Fe particles are located in the sodalite cages of the molecular sieve.
(10) The magnetic molecular sieve according to the above (9), wherein,
the Curie temperature of the magnetic molecular sieve is 500-700 ℃, preferably 500-600 ℃, and more preferably 550 ℃; and/or
The saturation magnetization of the magnetic molecular sieve at 25 ℃ is 8-12 emu/g, the saturation magnetization of the magnetic molecular sieve at 100 ℃ is 7-10 emu/g, and preferably, the saturation magnetization of the magnetic molecular sieve at 25 ℃ is 9-10 emu/g, and the saturation magnetization of the magnetic molecular sieve at 100 ℃ is 8-9 emu/g.
Drawings
FIG. 1 shows XRD spectra of HY type molecular sieve obtained in example 1 and NaY type molecular sieve as raw material;
FIG. 2 shows FeY type molecular sieves obtained in example 1 and Fe2O3Molecular sieve of type Y and Fe3O4-XRD spectrum of Fe/Y type molecular sieve;
FIG. 3 shows XRD spectra of a raw NaY type molecular sieve and the FeY type molecular sieve obtained in example 1;
FIG. 4 shows Fe obtained in example 13O4Curie temperature of-Fe/Y type molecular sieveA plot of degree;
FIG. 5 shows Fe obtained in example 13O4-a hysteresis loop of Fe/Y type molecular sieve at 25 ℃;
FIG. 6 shows Fe obtained in example 13O4-a hysteresis loop of the Fe/Y type molecular sieve at 100 ℃.
Detailed Description
The present invention will be described in further detail below with reference to examples and experimental examples. The features and advantages of the present invention will become more apparent from the description.
The invention provides a preparation method of a magnetic molecular sieve, which comprises the following steps:
According to a preferred embodiment of the present invention, in step 1, the molecular sieve is a Y-type zeolite molecular sieve.
In a further preferred embodiment, in step 1, the molecular sieve is a NaY-type zeolite molecular sieve.
Wherein the silicon-aluminum ratio of the NaY type molecular sieve is 5.0-5.3, and the specific surface area is more than or equal to 720m2The relative crystallinity is more than or equal to 90 percent, and the size of a molecular sieve pore channel is 0.3-1.6 um.
According to a preferred embodiment of the invention, step 1' is carried out before step 1:
step 1', activating the molecular sieve.
In a further preferred embodiment, in step 1', the activation treatment is performed at 400 to 600 ℃.
In a further preferred embodiment, in step 1', the activation treatment is carried out at 550 ℃, for example 500 ℃.
Wherein, the molecular sieve is activated, so that impurities such as carbon deposit can be removed, and the activation is preferably carried out for 2-6 h, more preferably for 3-5 h, for example 4 h.
According to a preferred embodiment of the invention, step 1 comprises the following sub-steps:
step 1-1, adding a molecular sieve into an ammonium salt solution for modification;
and step 1-2, after the modification is finished, carrying out suction filtration, drying and roasting to obtain the HY type molecular sieve.
According to a preferred embodiment of the present invention, in step 1-1, the ammonium salt is selected from ammonium acetate and/or amine halides.
In a further preferred embodiment, in step 1-1, the ammonium salt is selected from ammonium acetate and/or amine chloride.
In a still further preferred embodiment, in step 1-1, the ammonium salt is selected from ammonium acetate.
Wherein, in step 1-1, Na in the molecular sieve is removed by ion exchange+As much as possible substituted by NH4 +。
According to a preferred embodiment of the present invention, in step 1-1, the concentration of the ammonium salt solution is 0.1 to 0.5 mol/L.
In a further preferred embodiment, in the step 1-1, the concentration of the ammonium salt solution is 0.1 to 0.3 mol/L.
In a still further preferred embodiment, in step 1-1, the ammonium salt solution has a concentration of 0.2 mol/L.
According to a preferred embodiment of the present invention, in step 1-1, the ratio of the weight of the molecular sieve to the volume of the ammonium salt solution is 1 (20-80).
In a further preferred embodiment, in step 1-1, the ratio of the weight of the molecular sieve to the volume of the ammonium salt solution is 1 (40-60).
In a further preferred embodiment, in step 1-1, the ratio of the weight of the molecular sieve to the volume of the ammonium salt solution is 1 (45-55), for example 1: 50.
Wherein, in the step 1-1, the dosage ratio of the molecular sieve to the ammonium salt solution is the weight-to-volume ratio (g/mL).
According to a preferred embodiment of the present invention, in step 1-1, the modification is carried out as follows: the reaction is carried out for 12-24 hours at 60-120 ℃.
In a further preferred embodiment, in step 1-1, the modification is carried out as follows: the reaction is carried out for 18-24 hours at 80-100 ℃.
In a still further preferred embodiment, in step 1-1, the modification is carried out as follows: the reaction is carried out for 22-24 h at 90 ℃.
According to a preferred embodiment of the present invention, in step 1-2, the drying is performed at 80 to 140 ℃, preferably at 100 to 120 ℃.
According to a preferred embodiment of the present invention, in step 1-2, the firing is performed in an air and/or nitrogen atmosphere at 200 to 800 ℃.
In a further preferred embodiment, in step 1-2, the calcination is performed in an air and/or nitrogen atmosphere at 300 to 700 ℃.
In a further preferred embodiment, in step 1-2, the calcination is performed in an air and/or nitrogen atmosphere, preferably a nitrogen atmosphere, at 400 to 600 ℃.
Wherein, through roasting, NH in the molecular sieve after ammonium salt exchange can be promoted4+Is changed into H+Becomes an HY type molecular sieve, and preferably, the stability of the HY type molecular sieve can be further ensured under a nitrogen atmosphere.
In the invention, the ammonium salt modification does not damage the crystal structure of the molecular sieve, and specifically, after the ammonium salt modification, the relative intensities of diffraction peaks of three crystal faces (220), (311) and (331) in an XRD spectrogram are not changed, but the intensities are reduced, which indicates that the ammonium salt modification does not damage the crystal structure of the NaY type molecular sieve.
And 2, carrying out ion exchange on the HY molecular sieve obtained in the step 1 and a soluble iron salt solution.
Wherein, in the step 2, H in the HY type molecular sieve+With Fe in solution of soluble iron ions3+Ion exchange is carried out to make H in the molecular sieve as much as possible+Substitution to Fe3+。
According to a preferred embodiment of the present invention, in step 2, the soluble ferric salt solution comprises a ferric chloride solution, a ferric sulfate solution, a ferric nitrate solution and a ferric acetate solution.
In a further preferred embodiment, in step 2, the soluble iron salt solution comprises an iron chloride solution and an iron nitrate solution.
In a still further preferred embodiment, in step 2, the soluble iron salt solution is an iron nitrate solution.
According to a preferred embodiment of the present invention, in step 2, the ratio of the weight of the HY type molecular sieve to the volume of the soluble iron salt solution is 1 (20-80).
In a further preferred embodiment, in step 2, the weight ratio of the HY type molecular sieve to the volume of the soluble iron salt solution is 1 (40-60).
In a further preferred embodiment, in step 2, the weight ratio of the HY type molecular sieve to the volume of the soluble iron salt solution is 1 (45-55), such as 1: 50.
According to a preferred embodiment of the invention, in step 2, the ion exchange is carried out as follows: the reaction is carried out for 8-30 h at 60-120 ℃.
In a further preferred embodiment, in step 2, the ion exchange is carried out as follows: the reaction is carried out for 12-24 hours at 80-100 ℃.
In a still further preferred embodiment, in step 2, the ion exchange is carried out as follows: at 90 ℃ for 24 h.
If NaY type molecular sieve and Fe are directly adopted3+Ion exchange is carried out to easily produce Fe (OH)3Precipitation, and the Fe (OH)3The precipitate is difficult to migrate from the supercage to the sodalite cage, so that the precipitate only exists in the supercage, even if Fe is formed by roasting in the later period3O4However, the volume of the super cage of the molecular sieve is large, and Fe therein3O4Is prone to run off, resulting in a reduced lifetime of the magnetic molecular sieve.
In the invention, the molecular sieve is firstly treated to obtain the HY type molecular sieve, and then the HY type molecular sieve is treated in H+Under the condition of reacting with Fe3+Ion exchange is carried out so that it may be late-stage Fe3+The ion exchange process provides an acidic environment, thereby preventing the non-migratable Fe (OH)3The generation of a precipitate, butSupport Fe3+So that during the post-treatment, Fe3+Can exchange with sodium ions in the sodalite cages of the molecular sieve and enter the sodalite cages of the molecular sieve.
And 3, carrying out post-treatment to obtain the magnetic molecular sieve.
According to a preferred embodiment of the present invention, in step 3, the post-treatment comprises separation, drying and calcination.
In a further preferred embodiment, the drying is carried out as follows: drying for 4-18 h at 80-140 ℃ in air and/or nitrogen.
In a further preferred embodiment, the drying is carried out as follows: drying in air and/or nitrogen for 6-15 h at 100-120 ℃.
Wherein, in step 2, the Fe in the iron salt solution is dissolved3+With H in molecular sieves+Ion exchange takes place and Fe is made to pass through the roasting process3+Formation of Fe3O4And/or Fe, thereby imparting magnetic properties to the molecular sieve to enhance separation performance.
According to a preferred embodiment of the present invention, the firing is a three-stage firing in which the firing atmosphere is nitrogen, oxygen, and hydrogen in this order.
In a further preferred embodiment, the calcination is carried out at 300-700 ℃, preferably at 400-600 ℃, and more preferably at 450-550 ℃.
In a further preferred embodiment, the calcination is carried out for 4 to 20 hours, preferably 8 to 15 hours, for example 10 hours.
Wherein the roasting time is relative to Fe3+Migration and Fe3O4And/or the formation of Fe is critical.
According to a preferred embodiment of the invention, the firing is carried out in the following order: roasting for 2-8 h in a nitrogen atmosphere, roasting for 2-8 h in an oxygen atmosphere, and roasting for 1-5 h in a hydrogen atmosphere.
Wherein the primary purpose of the stage roasting is to promote Fe3+From the supercage of the molecular sieve to the beta cage of the molecular sieveGabion) migration. In the invention, the molecular sieve after nitrogen roasting is changed into the FeY type molecular sieve.
In a further preferred embodiment, the calcination is carried out in the following order: roasting for 4-6 h in a nitrogen atmosphere, roasting for 4-6 h in an oxygen atmosphere, and roasting for 2-4 h in a hydrogen atmosphere.
Wherein the main purpose of the stage of roasting is to promote the formation of Fe by iron ions in an oxygen atmosphere2O3。
In a still further preferred embodiment, the firing is carried out sequentially as follows: roasting for 4 hours in a nitrogen atmosphere, roasting for 4 hours in an oxygen atmosphere, and roasting for 2 hours in a hydrogen atmosphere.
Wherein the primary purpose of the stage roasting is to promote oxygen roasting to form Fe2O3Reacting with hydrogen to form magnetic Fe3O4。
Wherein, the difference of the roasting time under different atmospheres has obvious influence on the magnetic property of the product, specifically: (1) is beneficial to promoting Fe in the nitrogen roasting process3+Migrate to beta cage in the molecular sieve, and Fe in the molecular sieve when the nitrogen roasting time is short3 +The migration degree to the beta cage is low, and Fe is generated along with the extension of the nitrogen roasting time3+The mobility of the beta cage migration is greatly improved; (2) during the oxygen roasting process, the single Fe fixed in the Y molecular sieve body phase is formed2O3While improving the stability, Fe3+Oxidation, in the form of oxides, can reduce Fe during later use3O4The loss of the magnetic molecular sieve and the service life of the magnetic molecular sieve are prolonged, wherein if the roasting time in oxygen is too short, the Fe in the molecular sieve is influenced2O3The acquisition rate of (a); (3) fe in molecular sieve when hydrogen roasting time is short2O3Has a low reduction degree, and Fe is generated along with the extension of the hydrogen roasting time2O3The reduction degree is greatly improved, and when the roasting time of the hydrogen reaches a certain degree, the roasting time in the hydrogen is prolonged to cause excessive reduction, so that the magnetic property of the molecular sieve is influenced. Therefore, in the preparation process of the magnetic molecular sieveIn particular, the type of atmosphere used in each calcination stage and the calcination time have a significant effect on the magnetic properties of the resulting magnetic molecular sieve.
Among them, H in HY type molecular sieve+With Fe in soluble iron salts3+After ion exchange, hydrated iron ions are difficult to enter the sodalite cage 1 at room temperature and are mainly exchanged into the Y-type molecular sieve supercages. In the application, after a great deal of experimental research, the inventor finds that the roasting in the nitrogen atmosphere can be skillfully utilized to promote the migration of the hydrated iron ions to the sodalite cage (beta cage). Then roasting again to form Fe in sodalite cage (beta cage)3O4Particles and/or Fe particles, such that Fe is located in sodalite cages (β -cages)3O4Particles and/or Fe particles compared to Fe in supercages3O4The particles and/or Fe particles have better stability and are not easy to fall off. At the same time, Fe3O4And/or Fe particles migrating to the sodalite cage can inhibit dealumination of the zeolite framework, can enhance the thermal stability of the Y-type molecular sieve, and can counteract supercage B acid, namely protonic acid, and become a coking center if positioned in the supercage.
In another aspect of the present invention, there is provided a magnetic molecular sieve obtained by the method according to the first aspect of the present invention, wherein the molecular sieve is Fe3O4-Fe/Y type molecular sieves in which Fe is formed in situ within the Y molecular sieve3O4Particles and/or Fe particles, imparting magnetism to the molecular sieve, resulting in said magnetic molecular sieve for separation.
According to a preferred embodiment of the present invention, the Fe3O4The particles and/or the Fe particles are all on the nanometer scale.
In a further preferred embodiment, the Fe3O4The particles and/or Fe particles are located in the sodalite cages of the molecular sieve.
In a still further preferred embodiment, the Fe3O4The particles are in a spinel structure, and the Fe particles are in a body-centered cubic structure.
Wherein, the hydrated iron ions are difficult to enter into the sodalite cage and are mainly exchanged into the supercages of the molecular sieve at room temperature. After a large number of experimental researches, the sodalite cage is easy to enter the sodalite cage in the roasting process of the nitrogen atmosphere, and sodium ions in the sodalite cage are exchanged into the supercage.
According to a preferred embodiment of the present invention, the XRD diffraction pattern of the magnetic molecular sieve has Fe at 2 θ -43.02 °3O4Characteristic peaks of spinel structure.
In a further preferred embodiment, the XRD diffraction pattern of the magnetic molecular sieve has a characteristic peak of Fe body-centered cubic structure at 2 θ ═ 82.5 °.
In a further preferred embodiment, the magnetically modified molecular sieve has characteristic peaks in the XRD diffraction pattern in the (220), (311), (331) crystal planes, preferably with relative intensities I (331) > I (311) > I (220).
Wherein, Fe in the magnetic molecular sieve3O4The spinel structure and/or the Fe body-centered cubic structure are obvious, the strength is high, and the formed Fe3O4And/or the Fe particles are uniformly distributed, and, Fe3O4The structure or Fe body-centered cubic structure has good crystallization, regular crystal form and excellent magnetic property.
According to a preferred embodiment of the present invention, the magnetic molecular sieve has a curie temperature of 500 to 700 ℃.
In a further preferred embodiment, the magnetic molecular sieve has a Curie temperature of 500 to 600 ℃.
In a still further preferred embodiment, the magnetic molecular sieve has a curie temperature of 550 ℃.
The magnetic molecular sieve has a high Curie temperature which is far higher than the use temperature of most of the magnetic molecular sieves needing to be used as carriers, so that the application of the molecular sieve is extremely wide.
According to a preferred embodiment of the present invention, the saturation magnetization of the magnetic molecular sieve is 8 to 12emu/g at 25 ℃ and 7 to 10emu/g at 100 ℃.
In a further preferred embodiment, the magnetic molecular sieve has a saturation magnetization of 9 to 10emu/g at 25 ℃ and a saturation magnetization of 8 to 9emu/g at 100 ℃.
Wherein, for the magnetic molecular sieve, the stronger the saturation magnetization, the better the magnetic inductivity, the more thorough the separation, and the magnetic molecular sieve has less influence of temperature.
The invention has the advantages that:
(1) the method is simple, easy to realize, mild in operation condition, green and environment-friendly, and suitable for industrial production and application;
(2) the method of the invention adopts two-step ion exchange, and prevents Fe (OH)3Generating a precipitate;
(3) the method of the invention adopts multi-stage multi-atmosphere roasting to successfully lead Fe3+Migrating from the supercage of the molecular sieve to the sodalite cage of the molecular sieve;
(4) fe in the magnetic molecular sieve of the invention3O4The particles and/or Fe particles are uniformly distributed, the structure is good in crystallization, and the crystal form is regular;
(5) the magnetic molecular sieve has stable structure and is not easy to lose Fe in the using process3O4And/or Fe, so that the service life is long, the effect is good, and the magnetic molecular sieve can be recycled.
Examples
The invention is further described below by means of specific examples. However, these examples are only illustrative and do not limit the scope of the present invention.
Example 1
Activating a NaY type molecular sieve at 500 ℃ for 4h, then placing 1g of the activated molecular sieve in 50mL of ammonium acetate solution with the concentration of 0.2mol/L, and carrying out modification reaction at 90 ℃ for 24 h; and after the modification is finished, filtering, washing and drying the molecular sieve, and roasting the molecular sieve for 4 hours at 500 ℃ in a nitrogen atmosphere to obtain the HY type molecular sieve.
500mL of Fe (NO) having a concentration of 0.2mol/L was added to 1g of the obtained HY type molecular sieve3)3In solution and ion-exchanged at 90 deg.CAnd carrying out a shift reaction for 24 hours.
Then filtering, washing, drying at 100 deg.C for 12h, calcining at 500 deg.C under nitrogen atmosphere for 4h to obtain FeY type molecular sieve, and calcining at 500 deg.C under oxygen atmosphere for 4h to obtain Fe2O3Y type molecular sieve, and finally roasting for 2h at 500 ℃ in a hydrogen atmosphere to obtain the magnetic molecular sieve (Fe)3O4-Fe/Y type molecular sieves).
Example 2
Activating a NaY type molecular sieve at 500 ℃ for 4h, then placing 1g of the activated molecular sieve in 60mL of amine chloride solution with the concentration of 0.1mol/L, and carrying out modification reaction at 80 ℃ for 22 h; and after the modification is finished, filtering, washing and drying the molecular sieve, and roasting the molecular sieve for 3 hours at 600 ℃ in a nitrogen atmosphere to obtain the HY type molecular sieve.
40mL of FeCl with a concentration of 0.3mol/L was added to 1g of the obtained HY type molecular sieve3In solution, and ion exchange reaction is carried out for 12h at 100 ℃.
Then filtering, washing, drying at 80 deg.C for 18h, calcining at 450 deg.C under nitrogen atmosphere for 6h to obtain FeY type molecular sieve, and calcining at 450 deg.C under oxygen atmosphere for 6h to obtain Fe2O3Y type molecular sieve, and finally roasting for 3h at 450 ℃ in a hydrogen atmosphere to obtain the magnetic molecular sieve (Fe)3O4-Fe/Y type molecular sieves).
Example 3
Activating a NaY type molecular sieve at 550 ℃ for 3h, then placing 1g of the activated molecular sieve in 40mL of ammonium acetate solution with the concentration of 0.3mol/L, and carrying out modification reaction at 100 ℃ for 24 h; and after the modification is finished, filtering, washing and drying the molecular sieve, and roasting the molecular sieve for 5 hours at 400 ℃ in a nitrogen atmosphere to obtain the HY type molecular sieve.
1g of the obtained HY type molecular sieve was added to 60mL of a 0.1mol/L iron sulfate solution, and an ion exchange reaction was carried out at 90 ℃ for 24 hours.
Then filtering, washing, drying at 800 deg.C for 24h, calcining at 550 deg.C under nitrogen atmosphere for 4h to obtain FeY type molecular sieve, and calcining at 550 deg.C under oxygen atmosphere for 4h to obtain Fe2O3Y type molecular sieve, and finally roasting for 2h at 550 ℃ in hydrogen atmosphere to obtainThe magnetic molecular sieve (Fe)3O4-Fe/Y type molecular sieves).
Example 4
Activating a NaY type molecular sieve at 450 ℃ for 4h, then placing 1g of the activated molecular sieve in 20mL of amine chloride solution with the concentration of 0.5mol/L, and carrying out modification reaction at 60 ℃ for 24 h; and after the modification is finished, filtering, washing and drying the molecular sieve, and roasting the molecular sieve for 4 hours at 700 ℃ in a nitrogen atmosphere to obtain the HY type molecular sieve.
1g of the obtained HY type molecular sieve was added to 45mL of a 0.2mol/L iron acetate solution, and subjected to an ion exchange reaction at 120 ℃ for 8 hours.
Then filtering, washing, drying at 120 deg.C for 6h, calcining at 600 deg.C under nitrogen atmosphere for 3h to obtain FeY type molecular sieve, and calcining at 600 deg.C under oxygen atmosphere for 3h to obtain Fe2O3Y type molecular sieve, and finally roasting for 2h at 600 ℃ in hydrogen atmosphere to obtain the magnetic molecular sieve (Fe)3O4-Fe/Y type molecular sieves).
Example 5
Activating a NaY type molecular sieve at 400 ℃ for 6 hours, then placing 1g of the activated molecular sieve in 80mL of ammonium acetate solution with the concentration of 0.1mol/L, and carrying out modification reaction at 120 ℃ for 12 hours; and after the modification is finished, filtering, washing and drying the molecular sieve, and roasting the molecular sieve for 6 hours at 300 ℃ in a nitrogen atmosphere to obtain the HY type molecular sieve.
1g of the obtained HY type molecular sieve was added to 50mL of Fe (NO) at a concentration of 0.2mol/L3)3In solution and ion exchange reaction at 90 deg.c for 24 hr.
Then filtering, washing, drying at 140 deg.C for 4h, calcining at 400 deg.C under nitrogen atmosphere for 5h to obtain FeY type molecular sieve, and calcining at 400 deg.C under oxygen atmosphere for 5h to obtain Fe2O3Y type molecular sieve, and finally roasting for 3h at 400 ℃ in a hydrogen atmosphere to obtain the magnetic molecular sieve (Fe)3O4-Fe/Y type molecular sieves).
Comparative example
Comparative example 1
The procedure of example 1 was repeated except that the firing was carried out in the following order: firstly, roasting for 4 hours in an air atmosphere, and then roasting for 2 hours in a hydrogen atmosphere to obtain the magnetic molecular sieve.
Comparative example 2
The procedure of example 1 was repeated except that the firing was carried out in the following order: firstly roasting in the air atmosphere for 4 hours, then roasting in the nitrogen atmosphere for 4 hours, and finally roasting in the hydrogen atmosphere for 2 hours to obtain the magnetic molecular sieve.
Comparative example 3
The procedure of example 1 was repeated except that the firing was carried out in the following order: firstly roasting in nitrogen atmosphere for 4h, then roasting in air atmosphere for 4h, and finally roasting in hydrogen atmosphere for 2h to obtain the magnetic molecular sieve.
Examples of the experiments
Experimental example 1 XRD diffraction test
Experimental example 1-1
XRD diffraction tests were performed on the HY type molecular sieve obtained in example 1 and the NaY type molecular sieve as the raw material, and the XRD diffraction angles were 5-90 degrees, and the results are shown in FIG. 1.
It can be seen from fig. 1 that the relative intensities of the diffraction peaks of the three crystal planes (220), (311), and (331) of the NaY molecular sieve modified by ammonium acetate are not changed, but the intensities are reduced, which indicates that the crystal structure of the NaY molecular sieve modified by ammonium acetate is not damaged.
Experimental examples 1 to 2
For the FeY type molecular sieve obtained in example 1, Fe2O3Molecular sieve of type Y and Fe3O4XRD diffraction tests are respectively carried out on the Fe/Y type molecular sieve, and the XRD diffraction angle is 5-90 degrees, and the results are shown in figure 2.
Among these, it can be seen in fig. 2:
(1)Fe3O4the Fe/Y type molecular sieve has obvious diffraction peaks at the 2 theta of 18.24 degrees (110), 30.04 degrees (220), 35.38 degrees (311), 43.02 degrees (400), 53.42 degrees (422), 56.96 degrees (511), 62.52 degrees (440) and 83.88 degrees (533), which is similar to the standard Fe3O4The XRD patterns are consistent, and the molecular sieve can be judged to containSpinel type Fe3O4；
(2)Fe3O4The Fe/Y type molecular sieve has a characteristic peak of Fe body-centered cubic structure at the 2 theta of 82.5 degrees, and the molecular sieve can be judged to contain Fe body-centered cubic structure.
At the same time, with Fe2O3XRD diffraction peak ratio of/Y type molecular sieve, Fe3O4The XRD diffraction peak of the Fe/Y type molecular sieve is relatively weak and has obvious broadening phenomenon, which is caused by the small-size effect of the nano particles. And, spinel type Fe3O4The magnetic performance of the molecular sieve is good, and the nanometer size enables the magnetic performance of the molecular sieve to be more uniform and stable, so that the subsequent treatment of the molecular sieve used as a carrier is not influenced.
In example 1, as shown in fig. 3, the XRD spectrum of NaY type molecular sieve is compared with that of FeY type molecular sieve (N)2After calcination), the XRD pattern of the FeY-type molecular sieve was found to have a major peak position shifted to a large angle diffraction angle as a whole, presumably because: roasting in nitrogen atmosphere to obtain Fe3+Does not exist in the supercage but exists in the sodalite cage, namely Fe is successfully realized3+Migration from the supercage to the sodalite cage.
Wherein the FeY type molecular sieve is a molecular sieve calcined in a nitrogen atmosphere.
Experimental example 2 Curie temperature measurement
For Fe obtained in example 13O4The Curie temperature of the Fe/Y type molecular sieve was measured, and the results are shown in FIG. 4. it can be seen from FIG. 4 that Fe increases with the temperature3O4The magnetic induction of Fe/Y begins to decrease. At 550 deg.C, Fe3O4The magnetic properties of Fe/Y disappear and superparamagnetism appears. It can be seen that Fe3O4The Curie temperature of Fe/Y is 550 ℃. For most applications where the use of such magnetic molecular sieve supports is required, 550 ℃ is far in excess of the required requirement. This makes Fe3O4The range of applications of-Fe/Y becomes extremely broad.
Experimental example 3 characterization of hysteresis Loop
(1) For Fe obtained in example 13O4-Fe/Y type molecular sieves (20.1mg) were subjected to hysteresis loop characterization at 25 ℃ and 100 ℃ with the results shown in FIGS. 5-6, respectively, wherein:
as can be seen from FIG. 5, at 25 deg.C, Fe3O4The saturation magnetization of the Fe/Y type molecular sieve is 9.154emu/g, and the coercive force is 143 Oe;
as can be seen from FIG. 6, at 100 ℃ Fe3O4The saturation magnetization of the Fe/Y type molecular sieve is 8.706emu/g, and the coercive force is 143 Oe.
(2) Meanwhile, the magnetic molecular sieves obtained in comparative examples 1-3 were subjected to hysteresis loop characterization, and the results are shown in table 1.
Table 1:
wherein, for the magnetic molecular sieve as the carrier, the stronger the saturation magnetization, the better the magnetic induction, and the more thorough the separation; and the lower the coercive force is, the less agglomeration is easy to occur, and the dispersibility is better. As can be seen from Table 1, Fe obtained by the method of the present invention is comparable to the molecular sieves obtained by comparative examples 1 to 3 thereof3O4The molecular sieve of Fe/Y type (sample of example 1) has a high saturation magnetization and a low coercive force.
The invention has been described in detail with reference to the preferred embodiments and illustrative examples. It should be noted, however, that these specific embodiments are only illustrative of the present invention and do not limit the scope of the present invention in any way. Various modifications, equivalent substitutions and alterations can be made to the technical content and embodiments of the present invention without departing from the spirit and scope of the present invention, and these are within the scope of the present invention. The scope of the invention is defined by the appended claims.
Claims (13)
1. A method for preparing a magnetic molecular sieve, comprising the steps of:
step 1, modifying a molecular sieve to obtain an HY molecular sieve;
step 1' is performed before step 1:
step 1', activating a molecular sieve;
the activation treatment is carried out at 450-500 ℃;
step 1 comprises the following substeps:
step 1-1, adding a molecular sieve into an ammonium salt solution for modification;
the ammonium salt is selected from ammonium acetate and/or amine chloride, and the concentration of the ammonium salt solution is 0.1-0.3 mol/L;
the ratio of the weight of the molecular sieve to the volume of the ammonium salt solution is 1 (40-60), and the modification is carried out as follows: performing the reaction for 18 to 24 hours at a temperature of between 80 and 100 ℃;
step 1-2, after modification, carrying out suction filtration, drying and roasting to obtain an HY type molecular sieve;
the drying is carried out at 100-120 ℃, and the roasting is carried out at 400-600 ℃;
step 2, carrying out ion exchange on the HY molecular sieve obtained in the step 1 and a soluble iron salt solution;
the soluble ferric salt solution comprises ferric chloride solution and ferric nitrate solution;
the ratio of the weight of the HY type molecular sieve to the volume of the soluble iron salt solution is 1 (40-60);
the ion exchange is carried out as follows: performing the reaction at 80-100 ℃ for 12-24 h;
step 3, carrying out post-treatment to obtain the magnetic molecular sieve;
the post-treatment comprises separation, drying and roasting,
the roasting is three-stage roasting, wherein the roasting atmosphere comprises nitrogen, oxygen and hydrogen in turn,
the roasting is carried out at 300-700 ℃,
and roasting for 4-20 hours.
2. The method of claim 1,
the activation treatment is carried out at 500 ℃.
3. The method according to claim 1, wherein, in step 1-1,
the ammonium salt is selected from ammonium acetate; and/or
The concentration of the ammonium salt solution is 0.2 mol/L; and/or the ratio of the weight of the molecular sieve to the volume of the ammonium salt solution is 1 (45-55); and/or
The modification was carried out as follows: the reaction is carried out for 22-24 h at 90 ℃.
4. The method according to claim 3, wherein, in step 1-1,
the ratio of the weight of the molecular sieve to the volume of the ammonium salt solution was 1: 50.
5. The method according to claim 1, wherein, in step 2,
the soluble ferric salt solution is ferric nitrate solution; and/or
The weight ratio of the HY type molecular sieve to the volume of the soluble iron salt solution is 1 (45-55); and/or
The ion exchange is carried out as follows: at 90 ℃ for 24 h.
6. The method according to claim 5, wherein, in step 2,
the weight ratio of the HY type molecular sieve to the volume of the soluble iron salt solution is 1: 50.
7. The method according to claim 1, wherein, in step 3,
the drying is carried out as follows: drying for 4-18 h at 80-140 ℃ in air and/or nitrogen.
8. The method according to claim 7, characterized in that in step 3, the drying is carried out as follows: drying in air and/or nitrogen for 6-15 h at 100-120 ℃.
9. The method according to claim 1, wherein, in step 3,
the roasting is carried out at the temperature of 400-600 ℃;
and roasting for 8-15 h.
10. The method of claim 9,
the roasting is carried out at the temperature of 450-550 ℃;
the calcination was carried out for 10 h.
11. The method according to claim 1, characterized in that in step 3, the firing is carried out in the following order: roasting for 2-8 h in a nitrogen atmosphere, roasting for 2-8 h in an oxygen atmosphere, and roasting for 1-5 h in a hydrogen atmosphere.
12. The method of claim 11, wherein the firing is performed sequentially as follows: roasting for 4-6 h in a nitrogen atmosphere, roasting for 4-6 h in an oxygen atmosphere, and roasting for 2-4 h in a hydrogen atmosphere.
13. The method of claim 12, wherein the firing is performed sequentially as follows: roasting for 4 hours in a nitrogen atmosphere, roasting for 4 hours in an oxygen atmosphere, and roasting for 2 hours in a hydrogen atmosphere.
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| CN104628010A (en) * | 2013-11-08 | 2015-05-20 | 中国石油天然气股份有限公司 | Modification treatment method of Y-type zeolite |
| CN106145152A (en) * | 2015-03-31 | 2016-11-23 | 中国石油化工股份有限公司 | Modified Y zeolite and its preparation method and application |
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