Ion exchange method of molecular sieve containing alkaline metal

Abstract

The invention provides an ion exchange method of an alkaline metal-containing molecular sieve. The ion exchange method comprises a step of contacting a molecular sieve containing alkaline metal with an ion exchange liquid and carrying out ion exchange, positive ions in the ion exchange liquid comprise hydrogen ions (H < + >) and / or ammonium ions (NH4 < + >), and negative ions in the ion exchange liquid comprise peroxide ions (O2 < 2->). According to the method disclosed by the invention, the alkaline metal cations and the residual organic template agent in the molecular sieve can be removed at the same time, the post-treatment steps are simplified, and the emission load of VOCs (Volatile Organic Compounds) is reduced.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve materials technology, and specifically to an ion exchange method for alkali-containing metal molecular sieves. Background Technology

[0002] Molecular sieves are crystalline materials with an ordered framework structure and channels, with the most basic structural unit of their framework being the TO4 tetrahedron. In the typical preparation process of molecular sieves, trivalent ions are incorporated into the framework. To balance the framework charge, monovalent or divalent cations are simultaneously introduced; these cations are an important component of the molecular sieve. K and Na are the most common cations. Since molecular sieves are not acidic, ion exchange is required to replace the original cations, followed by calcination to obtain H-type acidic molecular sieves or molecular sieves containing other cations to meet specific application requirements.

[0003] In the crystallization step of molecular sieves, ammonium- or amine-containing organic compounds are generally added as template agents, which serve functions such as structure guidance, space filling, and balancing framework charges. Common template agents include organic amines (such as triethylamine, cyclohexylamine, hexamethylenediamine, hexamethyleneimine, etc.), quaternary ammonium bases (such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, etc.), and quaternary ammonium salts (such as tetramethylammonium bromide, tetraethylammonium bromide, etc.). After crystallization, the washing process removes any remaining template agent with water. Any template agent that is not completely removed needs to be dried, calcined, and decomposed at high temperature.

[0004] Ion exchange reactions of alkali metal molecular sieves are generally carried out in inorganic acid or inorganic ammonium salt solutions. Suitable inorganic ammonium salts for ammonium exchange are generally selected from ammonium sulfate, ammonium chloride, and ammonium nitrate. For example, CN112958166A discloses a method for molecular sieve ion exchange using ammonium sulfate, ammonium nitrate, and ammonium chloride as ion exchangers. CN103946159A discloses a method for ion exchange on sodium-containing zeolites using ammonium carbonate, while utilizing the property of ammonium carbonate to decompose into carbon dioxide and ammonia upon heating for recycling. Furthermore, ion exchange reactions of alkali metal molecular sieves can also be carried out in rare earth metal salt solutions. For instance, CN105800642A discloses a lanthanum-containing X-type molecular sieve and its preparation method. This involves mixing and stirring the X-type molecular sieve powder with a nitric acid aqueous solution, allowing it to stand, filtering, and drying. The resulting powder is then mixed and stirred with a lanthanum-containing nitric acid aqueous solution, and other conventional preparation methods are used to obtain a lanthanum-modified X-type molecular sieve.

[0005] Existing ion exchange methods all focus on using NH4 + The basic metal cations contained in the molecular sieve are exchanged, and then NH4 is removed during the drying and calcination process. +Ion decomposition yields H-type molecular sieves. To ensure complete removal of residual template agents from the molecular sieves, high calcination temperatures are often required. Furthermore, the decomposition of the template agents generates significant amounts of VOCs (volatile organic compounds), leading to environmental pollution. Summary of the Invention

[0006] To address one of the aforementioned technical problems in the prior art, this invention provides an ion exchange method for alkali metal molecular sieves. This method can achieve alkali metal ion exchange in the molecular sieve while removing residual organic template agents. It can not only efficiently prepare H-type acidic molecular sieves, but also greatly reduce the emission of volatile organic compounds during post-processing (e.g., calcination), thereby reducing environmental pollution.

[0007] In a first aspect, the present invention provides an ion exchange method for an alkali metal-containing molecular sieve, comprising the steps of contacting the alkali metal-containing molecular sieve with an ion exchange solution and performing ion exchange, wherein the cations in the ion exchange solution include hydrogen ions (H+). + ) and / or ammonium ions (NH4+) + The anions in the ion exchange solution include peroxide ions (O2). 2- ).

[0008] This invention selects H-containing + and / or NH4 + Cations and those containing O2 2- Anionic ion exchangers can achieve metal ion exchange in molecular sieves while also effectively removing organic matter from the molecular sieves.

[0009] According to some embodiments of the present invention, the cations in the ion exchange solution include hydrogen ions (H+). + The anions in the ion exchange solution include peroxide ions (O2). 2- ).

[0010] According to some preferred embodiments of the present invention, the cations in the ion exchange solution include hydrogen ions (NH4+). + The anions in the ion exchange solution include peroxide ions (O2). 2- ).

[0011] According to some embodiments of the present invention, the ion exchange solution includes an ion exchanger, which includes peroxyacid, peroxyacid ammonium salt, a combination of peroxyacid and peroxyacid ammonium salt, or a combination of peroxyacid and non-peroxyacid ammonium salt.

[0012] According to some embodiments of the present invention, the ion exchanger comprises a peroxy acid. In some embodiments, the peroxy acid comprises a peroxy inorganic acid and / or a peroxy organic acid having 1-6 carbon atoms. In some embodiments, the peroxy acid comprises a peroxy inorganic acid and / or a peroxy organic fatty acid having 1-6 carbon atoms. In some embodiments, the peroxy acid comprises a peroxy inorganic acid and / or a peroxy organic fatty acid having 1-4 carbon atoms. In some embodiments, the peroxy acid comprises a peroxy inorganic acid and / or a peroxy organic fatty acid having 2-4 carbon atoms. In some specific embodiments, the peroxy acid comprises one or more of persulfate, percarbonate, peroxyformic acid, peracetic acid, and peroxypropionic acid.

[0013] According to some embodiments of the present invention, the ion exchanger comprises an ammonium salt of the peroxy acid described above. In some embodiments, the ammonium salt of the peroxy acid comprises one or more of ammonium persulfate, ammonium percarbonate, ammonium peracetate, and ammonium peroxypropionate.

[0014] According to some embodiments of the present invention, the ion exchanger comprises a combination of the above-mentioned peroxyacid and the above-mentioned peroxyacid ammonium salt.

[0015] According to some embodiments of the present invention, the ion exchanger comprises a combination of the above-mentioned peroxyacid and a non-peroxyacid ammonium salt. In the present invention, the non-peroxyacid ammonium salt includes, but is not limited to, one or more of ammonium nitrate, ammonium sulfate, ammonium carbonate, and ammonium chloride. In some embodiments, the ion exchanger comprises a combination of one or more selected from persulfate, percarbonate, performic acid, peracetic acid, and perpropionic acid, and one or more selected from ammonium nitrate, ammonium sulfate, ammonium carbonate, and ammonium chloride.

[0016] According to some embodiments of the present invention, the ion exchanger includes one or more of ammonium persulfate, ammonium percarbonate, peroxyformic acid, peracetic acid, ammonium peracetate, perpropionic acid, and ammonium perpropionate.

[0017] According to some embodiments of the present invention, the ion exchanger includes one or more of ammonium persulfate, ammonium percarbonate, ammonium peracetate, and ammonium perpropionate.

[0018] According to some embodiments of the present invention, the mass concentration of the ion exchanger in the ion exchange solution is 1-30%, for example, 1%, 5%, 10%, 15%, 20%, 25%, 30%, etc. In some embodiments, the mass concentration of the ion exchanger in the ion exchange solution is 5-25%.

[0019] According to some embodiments of the present invention, the mass ratio of the alkali metal-containing molecular sieve to the ion exchange liquid is 1:(2-20), for example 1:2, 1:5, 1:8, 1:10, 1:12, 1:15, 1:18, 1:20, etc. In some embodiments, the mass ratio of the alkali metal-containing molecular sieve to the ion exchange liquid is 1:(5-15).

[0020] According to some embodiments of the present invention, the alkali metal in the alkali metal-containing molecular sieve includes alkali metals and / or alkaline earth metals. In some embodiments, the alkali metal in the alkali metal-containing molecular sieve includes alkali metals. In some embodiments, the alkali metal in the alkali metal-containing molecular sieve includes sodium. In some embodiments, the alkali metal in the alkali metal-containing molecular sieve includes potassium. In some embodiments, the alkali metal in the alkali metal-containing molecular sieve includes both sodium and potassium.

[0021] According to some embodiments of the present invention, the mass content of the alkali metal in the molecular sieve containing the alkali metal, based on the oxide of the alkali metal, is 0.1-8.0%, for example 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, etc., preferably 0.1-5%.

[0022] According to some embodiments of the present invention, the SiO2 / Al2O3 molar ratio of the alkali metal-containing molecular sieve is 5-1000, for example, 5, 10, 20, 30, 40, 45, 50, 60, 70, 80, 85, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, etc. In some embodiments, the SiO2 / Al2O3 molar ratio of the alkali metal-containing molecular sieve is 5-500. In some embodiments, the SiO2 / Al2O3 molar ratio of the alkali metal-containing molecular sieve is 5-300. In some embodiments, the SiO2 / Al2O3 molar ratio of the alkali metal-containing molecular sieve is 10-100.

[0023] According to some embodiments of the present invention, the molecular sieve containing alkali metals includes, but is not limited to: ZSM-5 molecular sieve, ZSM-35 molecular sieve, mordenite molecular sieve, β-zeolite molecular sieve, MCM-22 molecular sieve, etc.

[0024] According to some embodiments of the present invention, the alkali metal-containing molecular sieve further contains an organic template agent, which includes one or more of organic amines, quaternary ammonium bases, and quaternary ammonium salts. In some embodiments, the organic template agent includes one or more of triethylamine, cyclohexylamine, hexamethylenediamine, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, hexamethyleneimine, ammonium acetate, tetramethylammonium bromide, and tetraethylammonium bromide.

[0025] According to some embodiments of the present invention, the temperature for ion exchange is 20-85°C, for example, 20°C, 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 85°C, etc. In some embodiments, the temperature for ion exchange is 35-80°C.

[0026] According to some embodiments of the present invention, the ion exchange time is 0.3-10 hours, for example, 0.3 hours, 0.6 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, etc. In some embodiments, the ion exchange time is 0.6-8 hours.

[0027] According to some embodiments of the present invention, the ion exchange is carried out under stirring conditions.

[0028] According to some embodiments of the present invention, the ion exchange method of the alkali metal molecular sieve further includes the following steps:

[0029] The material after ion exchange is subjected to solid-liquid separation to obtain a solid phase;

[0030] The solid phase is dried and calcined.

[0031] In some embodiments, the drying temperature is 60-120℃, preferably 80-100℃. In some embodiments, the drying time is 1-10 hours. In some embodiments, the calcination temperature is 400-600℃. In some embodiments, the calcination time is 1-10 hours. The method of the present invention, by selecting a specific ion exchanger, can reduce the minimum calcination temperature of the molecular sieve from 550℃ to around 400℃, meaning that calcination at around 400℃ is sufficient to meet the requirements for the use of the molecular sieve.

[0032] According to some embodiments of the present invention, the ion exchange method of the alkali metal molecular sieve includes the following steps:

[0033] a) A molecular sieve containing alkali metal is mixed with an ion exchange solution and subjected to ion exchange; wherein the cations in the ion exchange solution include hydrogen ions (H+). + ) and / or ammonium ions (NH4+) + The anions in the ion exchange solution include peroxide ions (O2). 2- );

[0034] b) Perform solid-liquid separation on the material after ion exchange in step a) to obtain a solid phase and a liquid phase;

[0035] c) The solid phase obtained in step b) is dried and calcined to obtain the H-type molecular sieve product.

[0036] According to some embodiments of the present invention, the ion exchange method of the alkali metal molecular sieve includes the following steps:

[0037] a1) A molecular sieve containing an alkali metal is mixed with a solution containing an ion exchanger and ion exchange is performed; wherein the ion exchanger includes peroxy acid, ammonium peroxyate, a combination of peroxy acid and ammonium peroxyate, or a combination of peroxy acid and non-peroxyate ammonium salt, preferably including one or more of ammonium persulfate, ammonium percarbonate, peroxyformic acid, peracetic acid, ammonium peracetate, perpropionic acid, and ammonium perpropionate;

[0038] b1) Perform solid-liquid separation on the material after ion exchange in step a1) to obtain a solid phase and a liquid phase;

[0039] c1) The solid phase obtained in step b1) is dried and calcined to obtain the H-type molecular sieve product.

[0040] A second aspect of the present invention provides the application of an ion exchanger in ion exchange of alkali-containing metal molecular sieves or in the preparation of H-type acidic molecular sieves, wherein the ion exchanger comprises peroxyacid, peroxyacid ammonium salt, a combination of peroxyacid and peroxyacid ammonium salt, or a combination of peroxyacid and non-peroxyacid ammonium salt.

[0041] In some embodiments, the peroxy acid comprises a peroxy inorganic acid and / or a peroxy organic acid having 1-6 carbon atoms. In some embodiments, the peroxy acid comprises a peroxy inorganic acid and / or a peroxy organic fatty acid having 1-6 carbon atoms. In some embodiments, the peroxy acid comprises a peroxy inorganic acid and / or a peroxy organic fatty acid having 1-4 carbon atoms. In some embodiments, the peroxy acid comprises a peroxy inorganic acid and / or a peroxy organic fatty acid having 2-4 carbon atoms. In some specific embodiments, the peroxy acid comprises one or more of persulfate, percarbonate, performic acid, peracetic acid, and perpropionic acid. In some embodiments, the peroxy acid ammonium salt comprises one or more of ammonium persulfate, ammonium percarbonate, ammonium peracetate, and ammonium perpropionate. In some embodiments, the non-peroxy acid ammonium salt comprises one or more of ammonium nitrate, ammonium sulfate, ammonium carbonate, and ammonium chloride.

[0042] According to some embodiments of the present invention, the ion exchanger includes one or more of ammonium persulfate, ammonium percarbonate, peroxyformic acid, peracetic acid, ammonium peracetate, perpropionic acid, and ammonium perpropionate.

[0043] According to some embodiments of the present invention, the ion exchanger comprises one or more selected from persulfate, percarbonate, peroxyformic acid, peracetic acid, and peroxypropionic acid, and a combination of one or more selected from ammonium nitrate, ammonium sulfate, ammonium carbonate, and ammonium chloride.

[0044] According to some embodiments of the present invention, the alkali metal in the alkali-containing molecular sieve includes monovalent alkali metals and / or divalent alkali metals. In some embodiments, the alkali metal in the alkali-containing molecular sieve includes alkali metals and / or alkaline earth metals. In some embodiments, the alkali metal in the alkali-containing molecular sieve includes alkali metals. In some embodiments, the alkali metal in the alkali-containing molecular sieve includes sodium. In some embodiments, the alkali metal in the alkali-containing molecular sieve includes potassium. In some embodiments, the alkali metal in the alkali-containing molecular sieve includes both sodium and potassium.

[0045] According to some embodiments of the present invention, the mass content of the alkali metal in the alkali metal-containing molecular sieve, based on the oxide of the alkali metal, is 0.1-8.0%, for example, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, etc., preferably 0.1-5%.

[0046] According to some embodiments of the present invention, the SiO2 / Al2O3 molar ratio of the alkali-containing metal molecular sieve is 5-1000, for example, 5, 10, 20, 30, 40, 45, 50, 60, 70, 80, 85, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, etc. In some embodiments, the SiO2 / Al2O3 molar ratio of the alkali-containing metal molecular sieve is 5-500. In some embodiments, the SiO2 / Al2O3 molar ratio of the alkali-containing metal molecular sieve is 5-300. In some embodiments, the SiO2 / Al2O3 molar ratio of the alkali-containing metal molecular sieve is 10-100.

[0047] According to some embodiments of the present invention, the alkali-containing metal molecular sieve includes one or more of ZSM-5 molecular sieve, ZSM-35 molecular sieve, mordenite molecular sieve, β-zeolite molecular sieve, and MCM-22 molecular sieve.

[0048] According to some embodiments of the present invention, the alkali-containing metal molecular sieve further contains an organic template agent, which includes one or more of organic amines, quaternary ammonium bases, and quaternary ammonium salts. According to some embodiments of the present invention, the organic template agent includes one or more of triethylamine, cyclohexylamine, hexamethylenediamine, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, hexamethyleneimine, ammonium acetate, tetramethylammonium bromide, and tetraethylammonium bromide.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] In this invention, specific peroxides (peroxyacids or their ammonium salts) are selected as ion exchangers, which can fully ionize into hydrogen ions and NH4+ in aqueous solution. + While cations promote ion exchange reactions with basic metal ions in the molecular sieve, the ion exchanger can also ionize in water to release peroxide groups (O2). 2- It possesses strong oxidizing properties, capable of decomposing organic matter and efficiently removing residual organic template agents from molecular sieves, significantly reducing VOC emissions during post-processing. Furthermore, the method of this invention simplifies post-processing; only NH4 needs to be removed during subsequent drying and calcination. + The ions can be calcined at a minimum temperature of around 400℃ to meet the requirements for molecular sieve use, without the need to remove organic template agents at higher calcination temperatures, thus offering good economic, environmental, and application benefits. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[0052] Unless otherwise specified, the reagents used in the following embodiments and comparative examples of this invention are all commercially available products or reagents prepared according to conventional methods. Unless otherwise specified, the methods used in the following embodiments and comparative examples of this invention are all conventional experimental methods. Unless otherwise specified, the instruments used in the following embodiments and comparative examples of this invention are all commercially available.

[0053] In this invention, the term "alkaline metal" refers to a metal that can react with water to form an alkaline solution, such as alkali metals (lithium, sodium, potassium, rubidium, cesium, francium) and alkaline earth metals (beryllium, magnesium, calcium, strontium, barium, radium).

[0054] In this invention, the term "peroxyacid," abbreviated as "peracid," refers to an acid containing a peroxide group (-O-O-). Peroxyacids can be classified into inorganic peroxyacids (e.g., persulfate, percarbonate, etc.) and organic peroxyacids (e.g., peroxyformic acid, peracetic acid, perpropionic acid, etc.). Correspondingly, "peroxyacid ammonium salt" refers to the ammonium salt formed from the above-mentioned peroxyacids. Examples of peroxyacid ammonium salts include, but are not limited to, ammonium persulfate, ammonium percarbonate, ammonium peracetate, and ammonium perpropionate. Correspondingly, "non-peroxyacid" refers to organic and inorganic acids that do not contain the peroxide group (-O-O-). Examples of non-peroxyacids include, but are not limited to, hydrochloric acid, sulfuric acid, nitric acid, and carbonic acid. Correspondingly, "non-peroxyacid ammonium salt" refers to the ammonium salt formed from the above-mentioned non-peroxyacids. Examples of non-peroxyacid ammonium salts include, but are not limited to, ammonium salts formed from hydrochloric acid, sulfuric acid, nitric acid, and carbonic acid.

[0055] In this invention, the term "VOCs" refers to volatile organic compounds, including but not limited to alkanes (straight-chain alkanes, branched-chain alkanes, and cycloalkanes), alkenes, alkynes, benzene compounds, alcohols, aldehydes, ethers, ketones, acids, esters, and halogenated hydrocarbons, such as benzene, toluene, xylene, formaldehyde, styrene, trichloroethylene, chloroform, trichloroethane, ethyl acetate, n-hexane, diisocyanate, and diisocyanate toluene.

[0056] In the following examples and comparative examples, the Na content of the molecular sieves was analyzed and determined using an X-ray fluorescence spectrometer from Bruker GmbH, Germany, with an end-window Rh target ceramic tube, a 75 μm beryllium window, a maximum power of 4 kW, a maximum voltage of 60 kV, and a maximum current of 150 mA.

[0057] In the following examples and comparative examples, the content of organic template agent in molecular sieves is expressed by the measured organic carbon (TOC) content. The test method adopts the method of GB / T 32116-2015, and the test instrument is Shimadzu SSM-5000A organic carbon analyzer, which adopts combustion oxidation at 900℃, with a measurement range of 0.1-30 mgC and a sensitivity of 1-25 μgC.

[0058] Example 1

[0059] ZSM-5 molecular sieve was selected, with a SiO2 / Al2O3 molar ratio of 44.23, and containing tetraethylammonium hydroxide (calculated as C, content is 13.24 wt%) as a template agent. The Na content, calculated as Na2O oxide, is 4.22 wt%.

[0060] 60 kg of molecular sieve sample was added to 500 kg of ion exchanger (10% ammonium persulfate aqueous solution) and stirred at 35 °C for 0.6 h. Solid-liquid separation was then performed to obtain a filter cake and filtrate. The filter cake was dried at 90 °C and used as a sample for testing the organic carbon content. The TOC content in the sample was measured to be 3.39 wt% (calculated as C), a decrease of 74.4% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 580 °C, and the Na content was measured to be 0.05 wt%.

[0061] Example 2

[0062] ZSM-5 molecular sieve was selected, with a SiO2 / Al2O3 molar ratio of 1000, and containing triethylamine as a template agent (11.76 wt% as C). The Na content, calculated as Na2O oxide, was 4.13 wt%.

[0063] 60 kg of molecular sieve filter cake was added to 500 kg of ion exchanger (25% ammonium persulfate aqueous solution) and stirred at 65 °C for 8.0 h. Solid-liquid separation was then performed to obtain the filter cake and filtrate. The filter cake was dried at 90 °C and used as a sample for testing the organic carbon content. The TOC content in the sample was measured to be 1.98 wt% (calculated as C), a decrease of 83.2% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 450 °C, and the Na content was measured to be 0.02 wt%.

[0064] Example 3

[0065] β-zeolite was selected, with a SiO2 / Al2O3 molar ratio of 78.5, and containing tetraethylammonium hydroxide (15.28 wt% C). The Na content, calculated as Na2O oxide, was 4.14 wt%.

[0066] 100 kg of molecular sieve filter cake was added to 1500 kg of ion exchanger (15% peracetic acid aqueous solution) and stirred at 80 °C for 1.0 h. Solid-liquid separation was then performed to obtain the filter cake and filtrate. The filter cake was dried at 90 °C and used as a sample to test its organic carbon content. The TOC content in the sample was measured to be 8.48 wt% (calculated as C), a decrease of 44.5% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 500 °C, and the Na content was measured to be 0.02 wt%.

[0067] Example 4

[0068] MCM-22 molecular sieve was selected, with a SiO2 / Al2O3 molar ratio of 20.2, and containing the template agent hexamethylenetetramine (calculated as C, content is 9.96 wt%). The Na content, calculated as Na2O oxide, is 0.40 wt%.

[0069] 100 kg of molecular sieve filter cake was added to 500 kg of ion exchanger (5% ammonium persulfate aqueous solution) and stirred at 80 °C for 2.0 h. Solid-liquid separation was then performed to obtain the filter cake and filtrate. The filter cake was dried at 90 °C and used as a sample for testing the organic carbon content. The TOC content in the sample was measured to be 6.83 wt% (calculated as C), a decrease of 31.4% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 550 °C, and the Na content was not detected.

[0070] Example 5

[0071] ZSM-35 molecular sieve was selected, with a SiO2 / Al2O3 molar ratio of 25.6, and containing cyclohexylamine as a template agent (17.59 wt% as C). The Na content, calculated as Na2O oxide, was 0.23 wt%.

[0072] 100 kg of molecular sieve sample was added to 2000 kg of ion exchanger (5% ammonium percarbonate aqueous solution) and stirred at 35 °C for 0.6 h. Solid-liquid separation was then performed to obtain a filter cake and filtrate. The filter cake was dried at 90 °C and used as a sample for testing organic carbon content. The TOC content in the sample was measured to be 8.69 wt% (calculated as C), a decrease of 50.6% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 400 °C, and the Na content was undetectable.

[0073] Example 6

[0074] Mordenite molecular sieve was selected, with a SiO2 / Al2O3 molar ratio of 8.2, and containing tetraethylammonium hydroxide (calculated as C, content 20.04 wt%) as a template agent. The Na content, calculated as Na2O oxide, was 0.53 wt%.

[0075] 100 kg of molecular sieve sample was added to 1000 kg of ion exchanger (10% ammonium peracetate aqueous solution) and stirred at 35 °C for 0.6 h. Solid-liquid separation was then performed to obtain a filter cake and filtrate. The filter cake was dried at 90 °C and used as a sample for testing organic carbon content. The TOC content in the sample was measured to be 7.25 wt% (calculated as C), a decrease of 63.8% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 450 °C, and the Na content was measured to be 0.03 wt%.

[0076] Example 7

[0077] The only difference from Example 3 is that the ion exchanger is replaced with "a 15% peroxypropionic acid aqueous solution".

[0078] After ion exchange, the organic carbon content was tested, and the TOC content in the sample was found to be 9.67 wt% (calculated as C), a decrease of 36.7% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 500℃, and the Na content was measured to be 0.08 wt%.

[0079] Example 8

[0080] The only difference from Example 3 is that the ion exchanger is replaced with "ammonium peroxypropionate aqueous solution with a mass concentration of 15%".

[0081] After ion exchange, the organic carbon content was tested, and the TOC content in the sample was found to be 9.41 wt% (calculated as C), a decrease of 38.4% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 500℃, and the Na content was measured to be 0.10 wt%.

[0082] Example 9

[0083] The only difference from Example 3 is that the ion exchanger is replaced with "an aqueous solution containing 15% peracetic acid and 15% ammonium nitrate by mass".

[0084] After ion exchange, the organic carbon content was tested, and the TOC content in the sample was found to be 12.15 wt% (calculated as C), a decrease of 20.5% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 500℃, and the Na content was measured to be 0.01 wt%.

[0085] Comparative Example 1

[0086] The only difference from Example 1 is that the ion exchanger is replaced with a 10% (w / w) aqueous solution of ammonium nitrate. The specific method is as follows:

[0087] ZSM-5 molecular sieve was selected, with a SiO2 / Al2O3 molar ratio of 44.23, and containing tetraethylammonium hydroxide (calculated as C, content is 13.24 wt%) as a template agent. The Na content, calculated as Na2O oxide, is 4.22 wt%.

[0088] 60 kg of molecular sieve sample was added to 500 kg of ion exchanger (10% ammonium nitrate aqueous solution) and stirred at 35 °C for 0.6 h. Solid-liquid separation was then performed to obtain a filter cake and filtrate. The filter cake was dried at 90 °C and used as a sample for testing organic carbon content. The TOC content in the sample was measured to be 13.12 wt% (calculated as C), a decrease of 0.04% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 650 °C, and the Na content was measured to be 0.06 wt%.

[0089] Comparative Example 2

[0090] The only difference from Example 4 is that the ion exchanger is replaced with a 5% (w / w) ammonium acetate solution. The specific method is as follows:

[0091] MCM-22 molecular sieve was selected, with a SiO2 / Al2O3 molar ratio of 20.2, and containing the template agent hexamethylenetetramine (calculated as C, content is 9.96 wt%). The Na content, calculated as Na2O oxide, is 0.40 wt%.

[0092] 100 kg of molecular sieve filter cake was added to 500 kg of ion exchanger (5% ammonium acetate aqueous solution) and stirred at 80 °C for 2.0 h. Solid-liquid separation was then performed to obtain the filter cake and filtrate. The filter cake was dried at 90 °C and used as a sample to test its organic carbon content. The TOC content in the sample was measured to be 9.94 wt% (calculated as C), a decrease of 0.15% compared to the molecular sieve before ion exchange. Subsequently, the sample was calcined at 550 °C, and the Na content was measured to be 0.01 wt%.

[0093] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. An ion exchange method for a alkali metal-containing molecular sieve, comprising the steps of contacting the alkali metal-containing molecular sieve with an ion exchange solution and performing ion exchange, wherein, The cations in the ion exchange solution include hydrogen ions (H+). + ) and / or ammonium ions (NH4+) + The anions in the ion exchange solution include peroxide ions (O2). 2- ).

2. The ion exchange method according to claim 1, characterized in that, The ion exchange solution contains an ion exchanger, which includes peroxy acid, ammonium peroxyate, a combination of peroxy acid and ammonium peroxyate, or a combination of peroxy acid and non-peroxyate ammonium salt, preferably including peroxy acid and / or ammonium peroxyate, more preferably including ammonium peroxyate. Preferably, the peroxy acid includes peroxy inorganic acid and / or peroxy organic fatty acid having 1-6 carbon atoms, more preferably it includes one or more of persulfate, percarbonate, peroxyformic acid, peracetic acid and peroxypropionic acid. Preferably, the peroxymonophosphate salt includes one or more of ammonium persulfate, ammonium percarbonate, ammonium peracetate, and ammonium perpropionate; Preferably, the non-peroxymonophosphate salt includes one or more of ammonium nitrate, ammonium sulfate, ammonium carbonate, and ammonium chloride; Preferably, the ion exchanger comprises one or more of ammonium persulfate, ammonium percarbonate, peroxyformic acid, peracetic acid, ammonium peracetate, perpropionic acid, and ammonium perpropionate, or comprises a combination of one or more of persulfate, percarbonate, peroxyformic acid, peracetic acid, and perpropionic acid with one or more of ammonium nitrate, ammonium sulfate, ammonium carbonate, and ammonium chloride. Preferably, the mass concentration of the ion exchanger in the ion exchange solution is 1-30%, more preferably 5-25%.

3. The ion exchange method according to claim 1 or 2, characterized in that, The mass ratio of the alkali metal-containing molecular sieve to the ion exchange liquid is 1:(2-20), preferably 1:(5-15).

4. The ion exchange method according to any one of claims 1-3, characterized in that, The alkali metal in the molecular sieve containing alkali metals includes alkali metals and / or alkaline earth metals, preferably alkali metals, more preferably sodium and / or potassium; and / or, Based on the oxides of the alkali metal, the mass content of the alkali metal in the molecular sieve containing the alkali metal is 0.1-8.0%, preferably 0.1-5%; and / or, The SiO2 / Al2O3 molar ratio of the alkali metal-containing molecular sieve is 5-1000, preferably 5-500, more preferably 5-300, and even more preferably 10-100. Preferably, the alkali metal-containing molecular sieve includes one or more of ZSM-5 molecular sieve, ZSM-35 molecular sieve, mordenite molecular sieve, β-zeolite molecular sieve, and MCM-22 molecular sieve.

5. The ion exchange method according to any one of claims 1-4, characterized in that, The molecular sieve containing alkali metal also contains an organic template agent, which includes one or more of organic amines, quaternary ammonium bases, and quaternary ammonium salts. Preferably, the organic template agent includes one or more of triethylamine, cyclohexylamine, hexamethylenediamine, tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, hexamethyleneimine, ammonium acetate, tetramethylammonium bromide, and tetraethylammonium bromide.

6. The ion exchange method according to any one of claims 1-5, characterized in that, The temperature for ion exchange is 20-85℃, preferably 35-80℃; and / or the time for ion exchange is 0.3-10h, preferably 0.6-8h; and / or the ion exchange is carried out under stirring conditions.

7. The ion exchange method according to any one of claims 1-6, characterized in that, The method further includes the following steps: The material after ion exchange is subjected to solid-liquid separation to obtain a solid phase; The solid phase is dried and calcined.

8. The ion exchange method according to claim 7, characterized in that, The drying temperature is 60-120℃, preferably 80-100℃; and / or the drying time is 1-10h; and / or the calcination temperature is 400-600℃; and / or the calcination time is 1-10h.

9. The application of an ion exchanger in ion exchange of alkali metal molecular sieves or in the preparation of H-type acidic molecular sieves, wherein the ion exchanger comprises peroxyacid, peroxyacid ammonium salt, a combination of peroxyacid and peroxyacid ammonium salt, or a combination of peroxyacid and non-peroxyacid ammonium salt. Preferably, the ion exchanger comprises peroxyacid and / or ammonium peroxyacid salt; more preferably, the ion exchanger comprises ammonium peroxyacid salt.

10. The application according to claim 9, characterized in that, The peroxy acid includes peroxy inorganic acids and / or peroxy organic fatty acids having 1-6 carbon atoms, preferably including one or more of persulfate, percarbonate, performic acid, peracetic acid, and perpropionic acid; and / or, the peroxy acid ammonium salt includes one or more of ammonium persulfate, ammonium percarbonate, ammonium peracetate, and ammonium perpropionate; and / or, the non-peroxy acid ammonium salt includes one or more of ammonium nitrate, ammonium sulfate, ammonium carbonate, and ammonium chloride. Preferably, the ion exchanger comprises one or more of ammonium persulfate, ammonium percarbonate, peroxyformic acid, peracetic acid, ammonium peracetate, perpropionic acid, and ammonium perpropionate, or the ion exchanger comprises a combination of one or more of persulfate, percarbonate, peroxyformic acid, peracetic acid, and perpropionic acid with one or more of ammonium nitrate, ammonium sulfate, ammonium carbonate, and ammonium chloride.