ZSM-35 molecular sieve and preparation method thereof

Abstract

The present application provides a ZSM-35 molecular sieve and a preparation method thereof. The ZSM-35 molecular sieve is an aggregated ZSM-35 molecular sieve having a hierarchical macro-meso-microporous pore structure. Raw materials for the preparation method do not include an organic template agent and a crystal seed, and the preparation method includes the following steps: preparing a reactant gel where a molar ratio of SiO.sub.2, Al.sub.2O.sub.3, Na.sub.2O, K.sub.2O, oxygen-containing acid radical and H.sub.2O is (20-40):1.0:(1.5-2.0):(4.0-6.5):(1.0-4.0):(600-1200); sequentially performing an aging treatment and a crystallization treatment on the reactant gel, washing and drying a resulting synthetic product. The ZSM-35 molecular sieve provided by the present application may be obtained by synthesizing without using an organic template agent and crystal seed, and because it has a hierarchical pore structure, it is favorable for material diffusion and mass transfer.

Claims

1. A preparation method of a ZSM-35 molecular sieve, wherein raw materials for the preparation method do not comprise an organic template agent and a seed crystal, comprising steps of: preparing a reactant gel wherein a molar ratio of SiO.sub.2, Al.sub.2O.sub.3, Na.sub.2O, K.sub.2O, oxygen-containing acid radical and H.sub.2O is (20-40):1.0:(1.5-2.0):(4.0-6.5):(1.0-4.0):(600-1200); sequentially performing an aging treatment and a crystallization treatment on the reactant gel, and washing and drying a resulting synthetic product to obtain the ZSM-35 molecular sieve.

2. The preparation method according to claim 1, wherein reaction raw materials for preparing the reactant gel comprise an aluminum source, a silicon source, an acid phosphate, and water, and the oxygen-containing acid radical in the reactant gel is derived from the acid phosphate.

3. The preparation method according to claim 2, wherein the acid phosphate is selected from at least one of dipotassium hydrogen phosphate, disodium hydrogen phosphate, and diammonium hydrogen phosphate.

4. The preparation method according to claim 3, wherein performing the aging treatment on the reactant gel is at a temperature of 25-40 C., and an aging time is controlled to be not less than 2 h.

5. The preparation method according to claim 3, wherein the crystallization treatment has a temperature of 150-195 C. and a crystallization time of 48-120 h.

6. The preparation method according to claim 2, wherein the reaction raw materials further comprise one or more of sodium hydroxide, potassium hydroxide, sodium chloride and potassium chloride, to satisfy a pH of the reactant gel to 10-12 and a ratio of Na.sub.2O to K.sub.2O.

7. The preparation method according to claim 6, wherein performing the aging treatment on the reactant gel is at a temperature of 25-40 C., and an aging time is controlled to be not less than 2 h.

8. The preparation method according to claim 6, wherein the crystallization treatment has a temperature of 150-195 C. and a crystallization time of 48-120 h.

9. The preparation method according to claim 2, wherein performing the aging treatment on the reactant gel is at a temperature of 25-40 C., and an aging time is controlled to be not less than 2 h.

10. The preparation method according to claim 2, wherein the crystallization treatment has a temperature of 150-195 C. and a crystallization time of 48-120 h.

11. The preparation method according to claim 1, wherein performing the aging treatment on the reactant gel is at a temperature of 25-40 C., and an aging time is controlled to be not less than 2 h.

12. The preparation method according to claim 1, wherein the crystallization treatment has a temperature of 150-195 C. and a crystallization time of 48-120 h.

13. The preparation method according to claim 12, wherein the crystallization treatment is a two-stage crystallization treatment, wherein: the first-stage crystallization treatment is performed at 150-175 C. for 6-24 h, and the second-stage crystallization treatment is performed at 175-195 C. for 48-72 h; or the first-stage crystallization treatment is performed at 175-195 C. for 6-24 h, and the second-stage crystallization treatment is performed at 150-175 C. for 6-72 h.

14. The preparation method according to claim 12, wherein the crystallization is a rotational dynamic crystallization with a rotation rate of 30-60 rpm.

15. The preparation method according to claim 1, wherein the crystallization treatment is a two-stage crystallization treatment, wherein: the first-stage crystallization treatment is performed at 150-175 C. for 6-24 h, and the second-stage crystallization treatment is performed at 175-195 C. for 48-72 h; or the first-stage crystallization treatment is performed at 175-195 C. for 6-24 h, and the second-stage crystallization treatment is performed at 150-175 C. for 6-72 h.

16. The preparation method according to claim 15, wherein the crystallization is a rotational dynamic crystallization with a rotation rate of 30-60 rpm.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is an X-ray diffraction (XRD) spectrum of a ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(2) FIG. 2 is a 2000-fold magnified field emission scanning electron microscope (SEM) photograph of the ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(3) FIG. 3 is a 10000-fold magnified SEM photograph of the ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(4) FIG. 4 is a N.sub.2 adsorption-desorption isotherm curve of the ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(5) FIG. 5 is a BJH pore diameter distribution diagram of the ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(6) FIG. 6 is a mercury injection/mercury removal curve of the ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(7) FIG. 7 is a pore diameter distribution diagram corresponding to a mercury intrusion method of the ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(8) FIG. 8 is a transmission electron microscope (TEM) image of the ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(9) FIG. 9 is a partial high magnification TEM image of the ZSM-35 molecular sieve prepared according to Example 1 of the present application;

(10) FIG. 10 is a XRD spectrum of a ZSM-35 prepared according to Example 2 of the present application;

(11) FIG. 11 is a 5000-fold magnified SEM photograph of the ZSM-35 prepared according to Example 2 of the present application;

(12) FIG. 12 is a N.sub.2 adsorption-desorption isotherm curve of the ZSM-35 molecular sieve prepared according to Example 2 of the present application;

(13) FIG. 13 is a BJH pore diameter distribution diagram of the ZSM-35 molecular sieve prepared according to Example 2 of the present application;

(14) FIG. 14 is a XRD spectrum of a ZSM-35 prepared according to Example 3 of the present application;

(15) FIG. 15 is a 10000-fold magnified SEM photograph of the ZSM-35 prepared according to Example 3 of the present application;

(16) FIG. 16 is a XRD spectrum of a ZSM-35 prepared according to Example 4 of the present application;

(17) FIG. 17 is a XRD spectrum of a ZSM-35 prepared according to Example 5 of the present application;

(18) FIG. 18 is a XRD spectrum of a ZSM-35 prepared according to Example 6 of the present application;

(19) FIG. 19 is a XRD spectrum of a ZSM-35 prepared according to Example 7 of the present application;

(20) FIG. 20 is a 5000-fold magnified SEM photograph of the ZX-35 prepared according to Example 7 of the present application;

(21) FIG. 21 is a XRD spectrum of a ZSM-35 prepared according to Example 8 of the present application;

(22) FIG. 22 is a XRD spectrum of a ZSM-35 prepared according to Comparative Example 1 of the present application;

(23) FIG. 23 is a 5000-fold magnified SEM photograph of the ZSM-35 prepared according to Comparative Example 1 of the present application;

(24) FIG. 24 is a 20000-fold magnified SEM photograph of the ZSM-35 prepared according to Comparative Example 1 of the present application;

(25) FIG. 25 is a XRD spectrum of a ZSM-35 prepared according to Comparative Example 2 of the present application;

(26) FIG. 26 is a XRD spectrum of a ZSM-35 prepared according to Comparative Example 3 of the present application;

(27) FIG. 27 is a XRD spectrum of the ZSM-35 prepared according to Comparative Example 3 of the present application;

(28) FIG. 28 is a 3500-fold magnified SEM photograph of the ZSM-35 prepared according to Comparative Example 3 of the present application;

(29) FIG. 29 is a XRD spectrum of a ZSM-35 prepared according to Comparative Example 4 of the present application;

(30) FIG. 30 is a 5000-fold magnified SEM photograph of the ZX-35 prepared according to Comparative Example 4 of the present application.

DETAILED DESCRIPTION OF EMBODIMENTS

(31) To make the objectives, technical solutions, and advantages of embodiments of the present application clearer, the following clearly and comprehensively describes the technical solutions in the embodiments of the present application with reference to the accompanying drawings of the embodiments of the present application. Apparently, the described embodiments are merely part of embodiments rather than all embodiments of the present application.

(32) In the following examples and comparative examples:

(33) XRD spectrums were measured by a Bruck AXS D8 Advance X-ray diffractometer, Germany;

(34) SEM photographs were taken from a Zeiss ULTRA 55 field emission scanning electron microscope, Germany;

(35) BET specific surface area and pore structure parameters of a sample were measured using a Quanta chrome Autosorb iQ high performance fully automatic gas adsorber. Where the specific surface area of the sample was calculated by BET equation according to an adsorption equilibrium isotherm with a relative pressure between 0.05 to 0.25; a total pore volume is calculated by conversing an adsorption amount at a relative pressure of 0.99 into a liquid nitrogen volume; micropore specific surface area and micropore volume of the sample were calculated by a t-plot model; pore diameter distributions of mesopores and micropores of the sample were calculated by Barrett-Joyner-Halenda (BJH) method.

(36) A mercury intrusion adsorption experiment of the sample was carried out on an AutoPore IV 9500 mercury intrusion apparatus manufactured by Micromeritics Company, USA, with an experimental pressure of 0-30000 psia.

(37) The mentioned relative crystallinity of the ZSM-35 molecular sieve refers to a ratio, in percentage, of the sums of peak areas at 20=9.3, 22.3, 22.5, 23.3, 23.5, 24.4, 25.2 and 25.6 in a XRD spectrum of a synthesized product. The crystallinity of a ZSM-35 molecular sieve sample (Comparative Example 4) synthesized by the crystal seed method was set to be 100%.

Example 1

(38) 1.415 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until to clear and transparent. At the same time, 2.088 g of dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above clear and transparent solution, continuing to stir for 15 min, and then 24 g of a silica sol having a concentration of 30 wt. % (based on SiO.sub.2, the same below) was dropwise added to the resulting solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:2HPO.sub.4.sup.2:600H.sub.2O.

(39) Under stirring, the reactant gel was aged at about 25 C. for about 4 h to prepare a reactant gel precursor.

(40) The reactant gel precursor was transferred to a 100 mL reactor having a polytetrafluoroethylene liner, and dynamically crystallized in an oven at 175 C. for 72 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(41) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 112.6%, as shown in FIG. 1. It is determined through SEM that the ZSM-35 molecular sieve had a sphere-like aggregate morphology formed by stacking of crystal nanosheets, as shown in FIGS. 2 and 3.

(42) It is determined through gas sorption analyzer that the sample had a BET specific surface area of 325.3 m.sup.2/g, a microporous pore volume of 0.134 cm.sup.3/g, a mesoporous pore volume of 0.118 cm.sup.3/g, and a typical I and IV mixed type adsorption isotherm as shown in FIG. 4, indicating that the sample had an obvious meso-microporous pore channel structure characteristic; its hysteresis loop type belongs to H4 type, indicating that the adsorbent is a material containing narrow fracture-pores; as shown in a BJH pore diameter distribution diagram of FIG. 5, mesopores were distributed at 25-35 nm, while a certain amount of macropores were distributed at 60-100 nm.

(43) A mercury injection/mercury removal curve measured by a mercury intrusion method was shown in FIG. 6. There was a large hysteresis loop in the curve, indicating that there was a large number of macroporous pore channels in the sample, the macropores had a pore volume of 0.83 cm.sup.3/g. It could also be known from a corresponding pore diameter distribution curve diagram (FIG. 7) that there were scattered macroporous pore channels in the sample, and the pore diameter distribution thereof is 100-700 nm.

(44) The above results showed that the obtained ZSM-35 molecular sieve sample had a hierarchical macro-meso-microporous pore structure.

(45) FIG. 8 and FIG. 9 were transmission electron microscope images of the ZSM-35 molecular sieve, and FIG. 8 and FIG. 9 showed that the ZSM-35 molecular sieve had a particle size of about 6 m, and light transmitting portions in the figures were mesopores or macropores formed by stacking between crystal nanosheets.

Example 2

(46) 1.415 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until clear and transparent. At the same time, 1.044 g of dipotassium hydrogen phosphate having a purity of 95 wt. % and 0.894 g of potassium chloride having a purity of 98 wt. % were dissolved in 10 g of deionized water, which was dropwise added to the above clear and transparent solution, stirring for 15 min, and then 24 g of silica sol having a concentration of 30 wt. % was dropwise added to the resulting solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:1HPO.sub.4.sup.2:600H.sub.2O.

(47) Under stirring, the reactant gel was aged at about 40 C. for about 2 h to prepare a reactant gel precursor.

(48) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 175 C. for 72 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(49) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 104.5%, as shown in FIG. 10. It is determined through SEM that the ZSM-35 molecular sieve has a sphere-like aggregate formed by stacking of crystal nanosheets, as shown in FIG. 11.

(50) It is determined through gas sorption analyzer that the sample had a BET specific surface area of 312 m.sup.2/g, a microporous pore volume of 0.131 cm.sup.3/g, a mesoporous pore volume of 0.109 cm.sup.3/g, and a typical I and IV mixed type adsorption isotherm, as shown in FIG. 12, indicating that, as the same as Example 1, the sample also had a meso-microporous pore channel structure characteristic; its hysteresis loop type belonged to H4 type, indicating that the adsorbent is a material containing narrow fracture-pores; It could be known from a BJH pore diameter distribution diagram (FIG. 13) that mesopores of the molecular sieve were distributed at 20-30 nm, while a certain amount of macropores were at 40-80 nm. A mercury intrusion experiment showed that the sample had macroporous pore channels with a macroporous pore volume of 0.81 cm.sup.3/g and a macroporous pore diameter distribution of 100-650 nm.

(51) The above results showed that the obtained ZSM-35 molecular sieve sample had a hierarchical macro-meso-microporous pore structure.

Example 3

(52) 0.825 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 0.718 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until clear and transparent. At the same time, 1.218 g of dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above clear and transparent solution, stirring for 15 min, and then 14 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:2HPO.sub.4.sup.2:1200H.sub.2O.

(53) Under stirring, the reactant gel was aged at about 31-32 C. for about 3 h to prepare a reactant gel precursor.

(54) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 175 C. for 72 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(55) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 109.6%, as shown in FIG. 14. It is determined through SEM that the ZSM-35 molecular sieve has a sphere-like aggregate formed by stacking of crystal nanosheets, as shown in FIG. 15.

(56) It is determined through gas sorption analyzer that the sample had a BET specific surface area of 332 m.sup.2/g, a microporous pore volume of 0.131 cm.sup.3/g, a mesoporous pore volume of 0.119 cm.sup.3/g, and mesopores thereof were distributed at 25-35 nm, while a certain amount of macropores were at 45-80 nm. A mercury intrusion experiment showed that the sample had macroporous pore channels with a macroporous pore volume of 0.75 cm.sup.3/g and a macroporous pore diameter distribution of 100-650 nm.

(57) The above results showed that the obtained ZSM-35 molecular sieve sample had a hierarchical macro-meso-microporous pore structure.

Example 4

(58) 1.415 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until clear and transparent. At the same time, 2.088 g of dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above clear and transparent solution, stirring for 15 min, and then 24 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:2HPO.sub.4.sup.2:600H.sub.2O.

(59) Under stirring, the reactant gel was aged at about 25 C. for about 4 h to prepare a reactant gel precursor.

(60) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 150 C. for 120 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(61) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 100.5%, as shown in FIG. 16. It is determined through SEM that the ZSM-35 molecular sieve has a sphere-like aggregate morphology formed by stacking of crystal nanosheets.

(62) It is determined through gas sorption analyzer that the sample had a BET specific surface area of 332 m.sup.2/g, a microporous pore volume of 0.124 cm.sup.3/g, a mesoporous pore volume of 0.126 cm.sup.3/g, and mesopores thereof were distributed at 15-25 nm, while a certain amount of macropores were at 45-80 nm. A mercury intrusion experiment showed that the sample had macroporous pore channels with a macroporous pore volume of 0.78 cm.sup.3/g and a macroporous pore diameter distribution of 100-600 nm.

(63) The above results showed that the obtained ZSM-35 molecular sieve sample had a hierarchical macro-meso-microporous pore structure.

Example 5

(64) 1.415 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until clear and transparent. At the same time, 2.088 g of dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above clear and transparent solution, stirring for 15 min, and then 24 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:2HPO.sub.4.sup.2:600H.sub.2O.

(65) Under stirring, the reactant gel was aged at 25-40 C. for 2-4 h to prepare a reactant gel precursor.

(66) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 195 C. for 48 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(67) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 103.5%, as shown in FIG. 17. It is determined through SEM that the ZSM-35 molecular sieve has a sphere-like aggregate morphology formed by stacking of crystal nanosheets.

(68) It is determined through gas sorption analyzer that the sample had a BET specific surface area of 332 m.sup.2/g, a microporous pore volume of 0.121 cm.sup.3/g, a mesoporous pore volume of 0.119 cm.sup.3/g, and mesopores thereof were distributed at 20-35 nm, while a certain amount of macropores were at 40-90 nm. A mercury intrusion experiment showed that the sample had macroporous pore channels with a macroporous pore volume of 0.80 cm.sup.3/g and a macroporous pore diameter distribution of 100-600 nm.

(69) The above results showed that the obtained ZSM-35 molecular sieve sample had a hierarchical macro-meso-microporous pore structure.

Example 6

(70) 1.415 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until clear and transparent. At the same time, 2.088 g of industrial grade dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above clear and transparent solution, stirring for 15 min, and then 24 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:2HPO.sub.4.sup.2:600H.sub.2O.

(71) Under stirring, the reactant gel was aged at about 28 C. for about 3.5 h to prepare a reactant gel precursor.

(72) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, pre-crystallized in an oven at 150 C. for 24 h, and then dynamically crystallized at 175 C. for 72 h, the rotational speed was maintained at 60 rpm throughout the crystallization process. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(73) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 102.8%, as shown in FIG. 18. It is determined through SEM that the ZSM-35 molecular sieve has a sphere-like aggregate morphology formed by stacking of crystal nanosheets.

(74) It is determined through gas sorption analyzer that the sample had a BET specific surface area of 342 m.sup.2/g, a microporous pore volume of 0.132 cm.sup.3/g, a mesoporous pore volume of 0.112 cm.sup.3/g, and mesopores thereof were distributed at 25-40 nm, while a certain amount of macropores were at 50-90 nm. A mercury intrusion experiment showed that the sample had macroporous pore channels with a macroporous pore volume of 0.84 cm.sup.3/g and a macroporous pore diameter distribution of 100-700 nm.

(75) The above results showed that the obtained ZSM-35 molecular sieve sample had a hierarchical macro-meso-microporous pore structure.

Example 7

(76) 1.415 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until clear and transparent. At the same time, 2.088 g of dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above solution, stirring for 15 min, and then 24 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:2HPO.sub.4.sup.2:600H.sub.2O.

(77) Under stirring, the reactant gel was aged at 25-40 C. for 2-4 h to prepare a reactant gel precursor.

(78) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, pre-crystallized in an oven at 195 C. for 6 h, and then dynamically crystallized at 150 C. for 72 h, with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(79) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 108.7%, as shown in FIG. 19. It is determined through SEM that the ZSM-35 molecular sieve has a sphere-like aggregate formed by stacking of crystal nanosheets, and significantly small crystal size and aggregate size, as shown in FIG. 20.

(80) It is determined through gas sorption analyzer that the sample had a BET specific surface area of 353 m.sup.2/g, a microporous pore volume of 0.124 cm.sup.3/g, a mesoporous pore volume of 0.128 cm.sup.3/g, and mesopores thereof were distributed at 15-35 nm, while a certain amount of macropores were at 50-70 nm. A mercury intrusion experiment showed that the sample had macroporous pore channels with a macroporous pore volume of 0.73 cm.sup.3/g and a macroporous pore diameter distribution of 100-650 nm.

(81) The above results showed that the obtained ZSM-35 molecular sieve sample had a hierarchical macro-meso-microporous pore structure.

Example 8

(82) 1.238 g of potassium hydroxide having a purity of 95 wt. % and 0.077 g of sodium hydroxide having a purity of 99 wt. % were dissolved in 20 g of deionized water, and after stirring well, 0.861 g of industrial grade sodium metaaluminate having a purity of 80 wt. % was added, stirring until clear and transparent. At the same time, 2.923 g of dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above solution, stirring for 15 min, and then 33.6 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 2Na.sub.2O:6.5K.sub.2O:40SiO.sub.2:1Al.sub.2O.sub.3:4HPO.sub.4.sup.2:800H.sub.2O.

(83) Under stirring, the reactant gel was aged at 25-40 C. for 2-4 h to prepare a reactant gel precursor.

(84) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 175 C. for 72 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(85) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 108.5%, as shown in FIG. 21. It is determined through SEM that the ZSM-35 molecular sieve has a sphere-like aggregate formed by stacking of crystal nanosheets.

(86) It is determined through gas sorption analyzer that the sample had a BET specific surface area of 342 m.sup.2/g, a microporous pore volume of 0.126 cm.sup.3/g, a mesoporous pore volume of 0.129 cm.sup.3/g, and mesopores thereof were distributed at 20-30 nm, while a certain amount of macropores were at 40-80 nm. A mercury intrusion experiment showed that the sample had macroporous pore channels with a macroporous pore volume of 0.72 cm.sup.3/g and a macroporous pore diameter distribution of 100-650 nm.

(87) The above results showed that the obtained ZSM-35 molecular sieve sample had a hierarchical macro-meso-microporous pore structure.

Comparative Example 1

(88) 0.97 g of sodium hydroxide having a purity of 99 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until clear and transparent. At the same time, 2.088 g of dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above solution, stirring for 15 min, and then 24 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 3.5Na.sub.2O:2K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:2HPO.sub.4.sup.2:600H.sub.2O.

(89) Under stirring, the reactant gel was aged at 25-40 C. for 2-4 h to prepare a reactant gel precursor.

(90) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 175 C. for 72 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(91) It is determined through XRD that the phase of the synthetic product belongs to mordenite MOR, as shown in FIG. 22. It is determined through SEM that its crystal form is a massive aggregate formed by stacking of small cuboids, as shown in FIG. 23 and FIG. 24.

Comparative Example 2

(92) 0.25 g of sodium hydroxide having a purity of 99 wt. % and 1.061 g of potassium hydroxide having a purity of 95 wt. % were dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, continuing to stir until a clear and transparent solution is obtained. At the same time, 2.088 g of dipotassium hydrogen phosphate having a purity of 95 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above solution, stirring for 15 min, and then 24 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 2.0Na.sub.2O:3.5K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:2HPO.sub.4.sup.2:600H.sub.2O.

(93) Under stirring, the reactant gel was aged at 25-40 C. for 2-4 h to prepare a reactant gel precursor.

(94) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 175 C. for 72 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(95) It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve, but characteristic diffraction peak of mordenite is appeared at 2=9.77, as shown in FIG. 25.

Comparative Example 3

(96) 1.415 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until a clear and transparent solution is obtained. At the same time, 1.789 g of potassium chloride having a purity of 98 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above solution, stirring for 15 min, and then 24 g of silica sol having a concentration of 30 wt. % was dropwise added to the solution, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:600H.sub.2O.

(97) Under stirring, the reactant gel was aged at 25-40 C. for 2-4 h to prepare a reactant gel precursor.

(98) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 175 C. for 72 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was filtered, washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(99) It is determined through XRD that its phase belongs to a ZSM-35 molecular sieve, with a relative crystallinity of only 80.3%, as shown in FIG. 26.

(100) A reactant gel with the same molar ratio was prepared, and the crystallization time was extended to 96 h. After the reaction was completed, a resulting synthetic product was washed with deionized water until neutral, then dried at 120 C. for 5 h. It is determined through XRD that phase of the synthetic product belongs to a ZSM-35 molecular sieve with a relative crystallinity of 99.3%, as shown in FIG. 27. It is determined through SEM that its crystal form is a sphere-like aggregate formed by stacking of crystal nanosheets, as shown in FIG. 28. It is determined through gas sorption analyzer that the sample had a BET specific surface area of 341 m.sup.2/g, a microporous pore volume of 0.127 cm.sup.3/g, a mesoporous pore volume of 0.119 cm.sup.3/g, and mesopores thereof were distributed at 20-30 nm, while a certain amount of macropores were at 40-80 nm.

Comparative Example 4

(101) 1.415 g of potassium hydroxide having a purity of 95 wt. % was dissolved in 20 g of deionized water, and after stirring well, 1.23 g of sodium metaaluminate having a purity of 80 wt. % was added, stirring until a clear and transparent solution is obtained. At the same time, 1.789 g of potassium chloride having a purity of 98 wt. % was dissolved in 10 g of deionized water, which was dropwise added to the above solution, continuing to stir for 15 min, and then 2.4 g of ZSM-35 molecular sieve crystal seed were added to the solution, intensely stirring for 1 h, finally 24 g of silica sol having a concentration of 30 wt. % was dropwise added, a small amount of deionized water was supplemented after the addition of the silica sol was completed, intensely stirring for 30 minutes to obtain a reactant gel. The molar ratio of components in the reactant gel is about: 1.5Na.sub.2O:4K.sub.2O:20SiO.sub.2:1Al.sub.2O.sub.3:600H.sub.2O.

(102) Under stirring, the reactant gel was aged at 25-40 C. for 2-4 h to prepare a reactant gel precursor.

(103) The reactant gel precursor was transferred to a 100 mL reactor having polytetrafluoroethylene liner, and dynamically crystallized in an oven at 175 C. for 72 h with a rotational speed of 60 rpm. After the end of the crystallization, a resulting synthetic product was washed with deionized water until neutral, and then dried at 120 C. for 5 h.

(104) It is determined through XRD that its phase belongs to a ZSM-35 molecular sieve with a relative crystallinity of 100%, as shown in FIG. 29. It is determined through SEM that the crystal form of the ZSM-35 molecular sieve was lamellar, as shown in FIG. 30. It is determined through gas sorption analyzer that the sample had a BET specific surface area of 345 m.sup.2/g, a microporous pore volume of 0.162 cm.sup.3/g, and a mesoporous pore volume of only 0.066 cm.sup.3/g.

(105) Finally, it should be noted that the foregoing embodiments are merely intended for describing the technical solutions of the present application other than limiting the present application. Although the present application is described in detail with reference to the foregoing embodiments, persons of ordinary skill in the art should understand that they may still make modifications to the technical solutions described in the foregoing embodiments or make equivalent substitutions to some or all technical features therein; these modifications and substitutions will not make the spirit of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.