CN115970637B

CN115970637B - Adsorbent and preparation method and application thereof

Info

Publication number: CN115970637B
Application number: CN202210904142.5A
Authority: CN
Inventors: 胡晓倩; 王凤; 湛洪丽; 周君梦; 尹冬雪; 李丽; 王闯; 袁龙
Original assignee: Chia Tai Energy Materials Dalian Co ltd
Current assignee: Chia Tai Energy Materials Dalian Co ltd
Priority date: 2022-07-29
Filing date: 2022-07-29
Publication date: 2023-08-08
Anticipated expiration: 2042-07-29
Also published as: WO2024021342A1; CN115970637A

Abstract

The invention discloses an adsorbent, a preparation method and application thereof, wherein the adsorbent is provided with metal ions and a molecular sieve, and the molecular sieve powder is obtained by processing the following steps: the Raw-molecular sieve is contacted with a flocculating agent to form a solution, and the solution is dried and crushed to obtain molecular sieve powder.

Description

Adsorbent and preparation method and application thereof

Technical Field

The invention belongs to the technical field of adsorbents, and particularly relates to a molecular sieve type adsorbent, and a preparation method and application thereof.

Background

The adsorption separation process is widely applied to industrial processes such as separation and purification of organic substances such as dimethylbenzene, hydrogen production, oxygen production and the like, and the principle is that the separation is carried out by utilizing the difference of adsorption capacity of each component in the mixture on the solid surface of the adsorbent, and the performance of the adsorbent has an important influence on the adsorption separation effect. The adsorbent comprises active carbon, silica gel, active alumina, polymeric resin, molecular sieve and the like, wherein the molecular sieve adsorbent has the advantages of large specific surface area, high selectivity, high mechanical strength, stable chemical property and the like, and is commonly used in A type, X type, Y type, ZSM-5, mordenite and the like.

The ideal adsorbent should have a larger adsorption capacity, higher adsorption selectivity and faster mass transfer rate. By rolling to ball and gathering the molecular sieve crystal grains into small balls, the molecular sieve crystal grains in the small balls are piled up, mesoporous or macroporous are formed among the crystal grains, and micropores are formed in the molecular sieve crystal grains, so that the mass transfer of the adsorbate in the molecular sieve adsorbent is divided into the mass transfer in the adsorbed mesoporous or macroporous and the mass transfer in the micropores in the molecular sieve crystal grains, and the influence of the mass transfer in the crystal grains is larger because the pore channel size of the molecular sieve and the dynamic diameter of the adsorbate molecules are closer. Mass transfer efficiency in mesopores or macropores is generally improved by adding a pore-forming agent or reducing the size of the adsorbent during the formation of the adsorbent, and mass transfer efficiency in micropores is improved by using a small-particle-diameter or multi-pore molecular sieve.

Molecular sieves are generally in powder form and cannot be directly applied to fixed bed adsorption units, and therefore require the addition of binders to shape to provide some mechanical strength during use. The shaped adsorbent results in a reduced content of effective active ingredient due to the presence of the binder. Patent application CN108430924A discloses a method for making FAU-type binderless adsorbents by activating the adsorbent at a higher temperature to convert the kaolin binder to have reactive activity

The meta-kaolin is then converted to FAU-type zeolite in sodium silicate and caustic solution, the zeolite content in the adsorbent being greater than 98%. The method increases the adsorption capacity of the adsorbent per unit mass by increasing the content of the active component in the adsorbent, but with the continuous updating of the adsorbent preparation process, the method of converting the binder zeolite is insufficient to meet the requirement on the treatment capacity of an adsorption device, so that the bulk density of the adsorbent is also increased. When the volume of the adsorption tower is constant, the higher the packing density of the adsorbent, the larger the adsorption capacity of the whole adsorption tower.

Reducing the grain size of the molecular sieve can effectively shorten the diffusion path and improve the mass transfer efficiency, but the bulk density of the Raw-molecular sieve is smaller, so that the problem is that the bulk density and the compressive strength of the formed adsorbent taking the Raw-molecular sieve as an active component are lower.

The bulk density, i.e., the mass of adsorbent per unit volume, is related to the degree of compaction of the molecular sieve grain packing when the adsorbent particle size is fixed. Because of the fixed volume of the industrial adsorption device, the adsorbent with the mass as much as possible is required to be filled in the limited volume so as to improve the whole adsorption capacity and raw material processing capacity of the device and improve the production capacity.

Disclosure of Invention

1. Problems to be solved

Based on the existing adsorbent, the problem that the adsorbent has high adsorption capacity and high mass transfer rate can not be realized:

an object of the present invention is to provide an adsorbent excellent in adsorption performance;

it is a further object of the present invention to provide an adsorbent having a high bulk density and excellent adsorption performance;

the second object of the present invention is to provide a method for producing an adsorbent.

2. Technical proposal

In order to solve the problems, the technical scheme adopted by the invention is as follows:

an adsorbent having metal ions, and a molecular sieve active component;

the adsorbent has a particle size of not less than 600kg/m ³ Is a bulk density of (2);

wherein the molecular sieve active component is obtained by treatment in the following way: the Raw-molecular sieve is contacted with a flocculating agent to form a solution, and the solution is dried and crushed to obtain the molecular sieve; wherein, the liquid crystal display device comprises a liquid crystal display device,

the ratio of the addition mass of the flocculant to the addition mass of the molecular sieve is (0.05-1): 1, a step of; more preferably, the ratio is (0.1 to 0.5): 1, a step of;

the particle size D90 of the Raw-molecular sieve is not more than 1.5 mu m; more preferably, the particle size D90 of the Raw-molecular sieve is in the range of 0.2-1 μm.

The adsorbent is characterized in that the flocculant is used for treating the Raw-molecular sieve, and the particle size of the selected Raw-molecular sieve is a key for determining that the adsorbent provided by the invention has high bulk density, high mass transfer rate and high adsorption capacity and also has high mechanical strength. The Raw-molecular sieve has charges due to higher surface energy, and the flocculant has polar groups or charged groups, can neutralize the surface charges of crystal grains of the molecular sieve, eliminates repulsive force among the crystal grains, and enables the crystal grains to be closely stacked. Based on the technical scheme provided by the invention, the Raw-molecular sieve is used as an active component, so that the prepared adsorbent has good mass transfer performance, the surface charges of the grains of the Raw-molecular sieve can be neutralized through the treatment of the flocculant, the repulsive force among the grains is eliminated, the grains are closely stacked, and the defects of small stacking density and low compressive strength of the adsorbent prepared by the Raw-molecular sieve are overcome.

In some embodiments, after treatment of the Raw-NaX type molecular sieve with the flocculant is completed, the resulting molecular sieve will typically have a molecular weight of not less than 600kg/m ³ Is a bulk density of (2); the molecular sieves obtained in the preferred case will generally have a molecular weight of 650.+ -.10 kg/m ³ Is a bulk density of the polymer.

Based on the above, it is further explained that;

i) As described herein, the kind of metal ion may be arbitrarily selected according to purposes; preferably, the metal ion is preferably at least one of magnesium, strontium and barium in group IIA metal. In some embodiments, the Raw-molecular sieve is a NaX molecular sieve, and the final adsorbent has a sodium oxide content of no more than 0.6wt%, based on which:

in some embodiments, the metal ion is barium, then the adsorbent typically has a weight of no less than 800kg/m ³ Preferably having a bulk density of 880.+ -.10 kg/m ³ Bulk density within a range;

in other embodiments, the metal ion is strontium, then the sorbent generally has a weight of no less than 700kg/m ³ Preferably having a bulk density of 760.+ -.10 kg/m ³ Bulk density within a range;

in other embodiments, the metal ion is magnesium, and the adsorbent generally has a particle size of not less than 600kg/m ³ Preferably with a bulk density of 630.+ -.10 kg/m ³ Bulk density within a range;

in other embodiments, the metal ion is barium, strontium, then the adsorbent generally has a particle size of no less than 770kg/m ³ Preferably 770 to 880kg/m ³ Bulk density within a range;

In other embodiments, the metal ion is barium, magnesium, then the adsorbent generally has a particle size of not less than 650kg/m ³ Preferably 650 to 880kg/m ³ Bulk density in the range.

II) As used herein, "Raw-molecular sieves" refers to molecular sieves that have not been treated with a flocculant. Different types of Raw-molecular sieves may be selected for the particular application of the adsorbent, such as depending on the target species adsorbed by the adsorbent:

the target substance is paraxylene or paracresol, and then an alkaline earth metal supported FAU type molecular sieve is preferable, and further, the FAU type molecular sieve comprises an X molecular sieve and a Y molecular sieve; for example, "FAU zeolite molecular sieves and their membrane synthesis and characterization" (Liu Ying, university of gilin, 2014) are described in detail with respect to FAU-type molecular sieves.

When applied to the separation of O from air ₂ Then "Li-X molecular sieves" are preferred;

when applied to the removal of H ₂ The CO impurity in the catalyst is preferably a Cu-Y molecular sieve;

when applied to the separation of normal isoparaffins, "Ca-A molecular sieves" are preferred.

III) As described herein, the flocculant may be exemplified by one or more of polyacrylamide, polydimethyldiallylammonium chloride, sodium polyacrylate, sodium polystyrene sulfonate and sodium lignin sulfonate.

Further, in the process of obtaining the molecular sieve by the treatment: after the Raw-molecular sieve is contacted and mixed with a flocculating agent to form a solution, standing treatment is carried out firstly, and then precipitate is separated out for drying and crushing treatment;

the time of the standing treatment is not less than 10 minutes, preferably not less than 30 minutes. For example, the standing treatment can be 10 to 120 minutes; still more preferably, the standing time is 30 to 90 minutes.

Further, the separation mode is centrifugal separation, and the centrifugal rotation speed is not lower than 2000r/min.

Further, preparing the flocculant into a solution with the weight percent of 1-10%, and then contacting the flocculant with a molecular sieve; the volume ratio of the flocculant solution to the molecular sieve is (2-15): 1, the preferable ratio is (2 to 5): 1.

a method for producing an adsorbent which is loaded with metal ions and has a particle size of not less than 600kg/m ³ Is a bulk density of (2); the preparation method comprises the following steps:

s1, preparing a molecular sieve:

the Raw-molecular sieve is contacted with a flocculating agent to form a solution, and then the solution is dried and crushed to obtain the molecular sieve; the particle size D90 of the Raw-molecular sieve is not more than 1.5 mu m;

s2, preparing an adsorbent precursor:

molding a mixture containing a molecular sieve, a binder and a pore-forming agent, and then performing high-temperature treatment;

S3, crystallization treatment

Crystallizing the adsorbent precursor in an alkaline system;

s4, loading metal ions.

The metal ions of the adsorbent are carried out by using a solution containing the target metal ions.

In the above scheme, the treatment of the Raw-molecular sieve by the flocculant and the particle size of the Raw-molecular sieve are key to determining that the adsorbent provided by the invention has high bulk density, high mass transfer rate and high adsorption capacity and high mechanical strength. The Raw-molecular sieve has charges due to higher surface energy, and the flocculant has polar groups or charged groups, can neutralize the surface charges of crystal grains of the molecular sieve, eliminates repulsive force among the crystal grains, and enables the crystal grains to be closely stacked. Based on the technical scheme provided by the invention, the Raw-molecular sieve is used as an active component, so that the prepared adsorbent has good mass transfer performance, the surface charges of the grains of the Raw-molecular sieve can be neutralized through the treatment of the flocculant, the repulsive force among the grains is eliminated, the grains are closely stacked, and the defects of small stacking density and low compressive strength of the adsorbent prepared by the Raw-molecular sieve are overcome.

Based on the above, it is further explained that:

In S2, there is no particular requirement for the order of contacting the molecular sieve, binder and pore-forming agent. As a preferred option, the molecular sieve and the binder are typically mixed to form a mixture, and then the pore-forming agent is mixed in contact with the mixture in the form of an aqueous solution, in order to ultimately form a "shaped" article comprising the molecular sieve, binder and pore-forming agent, in order to ultimately form "particles" comprising the molecular sieve, binder and pore-forming agent;

the macrostructure morphology of the "particles" is not critical and may be spherical, bar-like or sheet-like; in some embodiments, the macroscopic morphology of the "particles" is spherical. The "pellet" molding method as described herein may be a conventional known molding method such as a known oil column molding method, a bar extrusion molding method, a spray molding method, a roll molding method, or the like. The size of the particles is not particularly limited and may be determined as required, and as a preferable mode, the particles have a particle diameter in the range of 0.3 to 3mm, and more preferably have a particle diameter in the range of 0.3 to 1 mm;

II) in S3, the in situ crystallization treatment is generally carried out in an alkaline solution. As a preferable scheme, the conditions of the in-situ crystallization treatment are as follows: the crystallization temperature is 90-120 ℃ and the crystallization time is 4-12 hours;

The alkaline solution is usually 1-3 mol/L, the alkali type is usually sodium hydroxide, potassium hydroxide, based on which the alkali solution contains Na ⁺ 、K ⁺ Alkali metal ions of the like;

further, in S1, after the Raw-molecular sieve is contacted and mixed with a flocculating agent to form a solution, standing treatment is carried out firstly, and then precipitate is separated out for drying and crushing treatment;

after the Raw-molecular sieve is added into the flocculant solution, stirring is carried out to enable the molecular sieve and the flocculant to fully contact and play a flocculation role, then the molecular sieve is allowed to slowly agglomerate and precipitate after standing, the flocculant can more fully play the flocculation role after standing for a period of time, then the molecular sieve and the flocculant solution are separated through centrifugation, and the flocculant solution can be reused.

Preferably, the time of the standing treatment is not less than 10min, preferably not less than 30min. In some embodiments, the standing process is performed for 10 to 120 minutes; in some more preferred embodiments, the resting time is from 30 to 90 minutes. If the standing time is too short, the flocculant does not sufficiently exert flocculation. When the concentration of the flocculant solution is low, if the standing time is too long, such as 24 hours, the flocculant is easy to degrade or the concentration is uneven.

In the step S1, the separation mode is centrifugal separation, and the centrifugal rotation speed is not lower than 2000r/min.

The magnitude of the centrifugal rotational speed is considered, and it is known that the degree of separation of the molecular sieve from the flocculant solution, i.e., the yield of the molecular sieve, is affected. In addition, the flocculant remained in the molecular sieve can act as a binder aid in the forming process due to certain viscosity. The flocculant solution after centrifugal separation can be reused.

Further, in S1, the drying temperature is not more than 150 ℃, preferably 90 to 130 ℃, and more preferably 90 to 110 ℃.

It should be noted here that the proper drying temperature should be chosen, especially that the maximum temperature should not exceed 150 ℃ and not exceed 130 ℃ as much as possible, since it has been found in research that too high a drying temperature can lead to degradation of the flocculant before the molecular sieve is formed, ultimately affecting the bulk density of the adsorbent.

Further, in S1, the flocculant is configured into a solution with the weight percent of 1-10 percent, and then is contacted with a molecular sieve;

the volume ratio of the flocculant solution to the molecular sieve is (2-15): 1, a step of;

the flocculation temperature can generally be chosen to be room temperature.

It should be noted here that the flocculant solution concentration must not be too low, otherwise no ideal flocculation occurs; the flocculant solution concentration must not be too high, otherwise the flocculant solution will be relatively viscous; or the volume of the flocculant solution is too small, the volume ratio of the flocculant solution to the molecular sieve is not less than 2 in theory, otherwise, the mixed slurry is not easy to stir uniformly after the molecular sieve is added into the flocculant solution, so that the flocculant and the molecular sieve cannot be fully contacted.

As a preferable scheme, the volume ratio of the flocculant solution to the molecular sieve is (2-5): 1.

further, in S2, the addition amount of the molecular sieve is higher than the addition amount of the binder, but the addition amount of the binder is not lower than 5wt% of the total addition amount of the molecular sieve and the binder; preferably, the addition amount of the molecular sieve is at least four times of the addition amount of the binder, and the addition amount of the binder is not lower than 5wt% of the addition amount of the molecular sieve; as a further preferable scheme, the adding mass ratio of the molecular sieve to the binder is (80-95): (5-20);

the addition amount of the pore-forming agent is 1-5 wt% of the total weight of the molecular sieve and the binder dry basis; further preferably 1 to 3wt%;

further, in S2, the temperature of the high-temperature treatment is 550-950 ℃; further preferably the temperature is 550 to 750 ℃;

The treatment time of the high-temperature treatment is 1 to 8 hours.

It should be noted that the flocculant and pore-forming agent may be removed by decomposition into volatile components under the firing conditions, or may be removed by water washing without affecting the subsequent binder crystallization process by only residual sodium or potassium.

Further, the flocculant comprises one or more of polyacrylamide, polydimethyl diallyl ammonium chloride, sodium polyacrylate, sodium polystyrene sulfonate and sodium lignin sulfonate;

the pore-forming agent comprises one or more of starch, lignin, polyethylene glycol and sodium carbonate;

the binder comprises one or more of kaolin, bentonite, perlite and halloysite.

Further, in S4, the crystallized product is directly contacted with a solution containing target metal ions, and cation exchange is performed to realize loading of the target metal ions, thereby obtaining the adsorbent product loaded with the metal.

Exchange to M in adsorbent _X The O content is not higher than 0.6wt%. M is a metal ion species carried by the molecular sieve itself, such as sodium ion, in which case M _X O is Na ₂ O。

Further, the S4 specifically comprises

Firstly, carrying out ammonium ion exchange treatment on a crystallized product by utilizing an ammonium salt solution;

Then, the solution is contacted with a solution containing target metal ions to realize the loading of the target metal ions, and the adsorbent product loaded with the metal is obtained.

Wherein the saturated water absorption of the product after the ammonium ion exchange treatment is determined, and the amount of the solution containing the target metal ion does not exceed the saturated water absorption of the product.

Further, the ammonium ion exchange treatment includes:

contacting the solution containing ammonium ions with the crystallized product, and detecting the content of alkali metal ions in the contacted solution to ensure that the content of the alkali metal ions is less than or equal to 0.1wt percent, so that the ion removal treatment is completed;

preferably, the ammonium salt is added at a concentration of 0.05 to 0.3mol/L.

It is to be noted here that I) the "alkali metal ions" as described herein include in particular ions introduced in the crystallization step, which is generally carried out in an alkaline solution, which is generally in a concentration of 1 to 3mol/L, and the alkali type is generally sodium hydroxide, potassium hydroxide, based on which, for example, na is contained ⁺ 、K ⁺ Awaiting the removed ions.

II) the ammonium salt has solubility, and is generally any one or more of ammonium chloride, ammonium carbonate and ammonium sulfate. In the alkali metal ion removal treatment process, the treatment temperature is kept at 60-80 ℃, deionized water is used for washing until the pH value is neutral after the treatment is finished, and then the alkali metal ion removal treatment process is carried out at a temperature not exceeding 100 ℃.

Further, placing the crystallized product in a container, and continuously introducing a solution containing ammonium ions into the container;

wherein the container is provided with a liquid inlet and a liquid outlet;

the volume airspeed of the ammonium salt solution is 2 to 8 hours ^-1 . Further preferably, the space velocity is 3 to 6 hours ^-1 。

Further, the solution containing the target metal ions is contacted with the product after the ammonium ion exchange treatment in the form of small liquid drops, then the solution is subjected to standing treatment, and finally the solution is subjected to drying and high-temperature treatment.

It should be noted that, the solution containing the target metal ions is diffused into the molecular sieve pores by utilizing the gravity, the surface tension and the adsorptivity of the liquid, and then the water is evaporated by drying, so that the target metal ions are uniformly distributed on the inner surface of the molecular sieve, thereby not only reducing the dosage of the solution containing the target metal ions and improving the utilization rate of the solution containing the target metal ions, but also the load distribution of the target metal ions is uniform and the load capacity can be precisely controlled.

Preferably, in the process of realizing contact between the solution containing the target metal ions and the product after the ammonium ion exchange treatment in the form of small liquid drops, the solution containing the target metal ions is sprayed on the product after the ammonium ion exchange treatment while stirring until the product after the ammonium ion exchange treatment is completely wetted.

Further, the time of the standing treatment is 30-120 min.

It should be noted that i) atomizing the solution containing the target metal ions into fine droplets as fine as possible by using an atomizer, the smaller the droplets are, the more favorable the solution is sprayed uniformly;

II) the purpose of the "stand still treatment" as described herein is to allow the solution containing the target metal ions to diffuse sufficiently into the channels of the molecular sieve, the stand still time affecting the degree of dispersion of the target metal ions on the adsorbent. If the standing time is too short of 30min, for example, 15min, the metal ions are unevenly distributed;

further, the metal is a group IIA metal, such as magnesium, strontium, barium.

The adsorbent prepared by any one of the methods is applied to the target product obtained by adsorption separation from the mixture; the target product comprises paraxylene, paracresol and the like.

Drawings

FIG. 1 is an electron microscope image of Raw Raw-molecular sieve powder used in example 1;

FIG. 2 is an electron micrograph of a large particle size molecular sieve raw powder used in comparative example 1.

Detailed Description

The present disclosure may be understood more readily by reference to the following description taken in conjunction with the accompanying drawings and examples, all of which form a part of this disclosure. It is to be understood that this disclosure is not limited to the particular products, methods, conditions, or parameters described and/or shown herein. Further, the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting unless otherwise indicated.

It is also to be appreciated that certain features of the disclosure may, for clarity, be described herein in the context of separate embodiments, but may also be provided in combination with each other in a single embodiment. That is, each separate embodiment is contemplated to be combinable with any other embodiment, and to be considered as representing a different embodiment, unless expressly incompatible or specifically excluded. Conversely, various features of the disclosure that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Finally, although a particular embodiment may be described as part of a series of steps or as part of a more general structure, each step or sub-structure itself may also be considered a separate embodiment.

Unless otherwise indicated, it should be understood that each individual element in the list and each combination of individual elements in the list are to be construed as different embodiments. For example, a list of embodiments denoted as "A, B or C" should be construed to include embodiments "a", "B", "C", "a or B", "a or C", "B or C" or "A, B or C".

In this disclosure, the singular forms "a," "an," and "the" also include the corresponding plural referents, and reference to a particular value includes at least the particular value unless the context clearly dictates otherwise. Thus, for example, reference to "a substance" is a reference to at least one of such a substance and equivalents thereof.

Terms including ordinal numbers such as "first" and "second" may be used to explain various components or fluids, but the components, fluids are not limited by these terms. Accordingly, these terms are merely used to distinguish one component/fluid from another component/fluid without departing from the teachings of the present disclosure.

When items are described using the conjunctive terms "… … and/or … …" and the like, the description should be understood to include any one of the associated listed items, and all combinations of one or more of the same.

In general, the use of the term "about" refers to an approximation that may vary depending on the desired properties obtained by the disclosed subject matter, and will be interpreted in a context-dependent manner based on the function. Thus, one of ordinary skill in the art will be able to interpret a degree of variability on an individual case basis. In some cases, the number of significant digits used in expressing a particular value can be a representative technique for determining the variance allowed by the term "about. In other cases, a gradient in a series of values may be used to determine the range of differences permitted by the term "about". Further, all ranges in this disclosure are inclusive and combinable, and reference to a value recited in a range includes each value within the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; the term and/or any and all combinations including one or more of the associated listed items.

The present invention is further illustrated below with reference to specific examples, which are not intended to limit the invention in any way. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art. The essential features and significant effects of the invention can be seen from the following examples, which are described as some, but not all, of which, therefore, are not limiting of the invention, and some of the insubstantial modifications and adaptations of the invention by those skilled in the art are within the scope of the invention.

In the following specific examples:

the Raw-molecular sieves used in examples 1-3, 5-13 had particle size (D90) within no more than 1.5 μm. D90 was detected using a Malvern particle size analyzer (model Malvern MS 2000).

The detection instruments used were: an on-line mass spectrometer (model Hiden HPR 20), a gas chromatograph (model Agilent 7890B), an inductively coupled plasma emission spectrometer (model thermo cap 7000).

The method for performing in-situ crystallization treatment comprises the following steps: the adsorbent precursor was placed in a mixed solution of 1.6mol/L NaOH and 0.4mol/L KOH and crystallized at 100℃for 6 hours.

The method for calculating the barium exchange degree of the adsorbent comprises the following steps: the molar amount of barium in the sample is W1, the molar amount of aluminum is W2, and the degree of barium exchange is [ (2X W1)/W2)]*100%. In the following examples, the barium content of the sprayed barium solution was such that the NH was theoretically obtained ₄ ⁺ The barium exchange degree of the molecular sieve reaches 99 percent.

The specific method for measuring the saturated water absorption of the sample comprises the following steps: direction 1gNH ₄ ⁺ And (3) dropwise adding water into the powder sample while continuously stirring until the surface of the sample is just completely wetted, thus obtaining the saturated water absorption capacity of the sample with unit mass. The active component content in the adsorbent is 98% or more by zeolitizing the binder, so that it is considered that NH ₄ ⁺ The saturated water absorption of the shaped powder and the pellets are the same.

The specific method for measuring the adsorption capacity of the adsorbent comprises the following steps: filling a certain mass of adsorbent into a fixed bed reactor, purging for 1 hour at 550 ℃ in nitrogen, cooling to 40 ℃, introducing 500ppm of toluene (nitrogen balance) until adsorption saturation, and quantitatively analyzing the gas composition at the tail end of the adsorbent by using an online gas mass spectrometer, wherein the adsorption capacity of the adsorbent is the toluene adsorption quantity before a penetration point.

The specific method for measuring the bulk density of the adsorbent comprises the following steps: roasting the adsorbent for 1 hour at 550 ℃, transferring to a vacuum dryer, cooling to room temperature, pouring the adsorbent into a measuring cylinder, oscillating until the volume is unchanged, recording the volume and the mass of the adsorbent in the measuring cylinder, and calculating to obtain the mass of the adsorbent in unit volume.

The specific method for measuring the mechanical strength of the adsorbent comprises the following steps: and (3) absorbing water of the adsorbent in air to be saturated, then loading the adsorbent into a stainless steel cylinder, covering a cylindrical thimble matched with the inner diameter of the stainless steel cylinder, then placing the stainless steel cylinder on a particle strength tester for 5 minutes under 250N pressure, pouring the adsorbent into a 300 mu m standard sieve for sieving after pressure relief, and calculating the ratio of the mass of a crushed sample to the initial mass to obtain the crushing rate.

Example 1

Preparing a 1wt% polyacrylamide aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of a flocculant solution to the molecular sieve is 15:1. after standing for 30 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 90 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the kaolin is 82:18;

uniformly stirring NaX molecular sieve and kaolin, adding starch accounting for 3wt% of the total weight of the molecular sieve and kaolin, fully and uniformly stirring, rolling and forming, and sieving to obtain small balls with the diameter of 0.3-1 mm after drying.

Roasting the pellets at 600 ℃ for 6 hours to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

And (3) contacting the crystallized pellets with barium chloride solution to perform cation exchange.

The result of electron microscopy of the Raw-NaX molecular sieve is shown in FIG. 1, and the D90 of the molecular sieve is 0.9 μm. The bulk density, mechanical strength and adsorption capacity of the adsorbents are shown in Table 1.

Example 2

Preparing 10wt% polydimethyl diallyl ammonium chloride aqueous solution, adding a Raw-NaKX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of the flocculant solution to the molecular sieve is 2:1. after standing for 10 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 130 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the bentonite is 80:20;

uniformly stirring the molecular sieve and the bentonite, adding lignin accounting for 5wt% of the total weight of the molecular sieve and the bentonite, fully and uniformly stirring, rolling and forming, and sieving to obtain the pellets with the diameter of 0.3-1 mm after drying.

The pellets were calcined at 550 ℃ for 8 hours to obtain an adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

And (3) contacting the crystallized pellets with a barium nitrate solution for cation exchange.

The bulk density, mechanical strength and adsorption capacity are shown in Table 1.

Example 3

Preparing a 3wt% sodium polyacrylate aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of a flocculant solution to the molecular sieve is 10:1.

after standing for 120 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 100 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the perlite is 84:16;

uniformly stirring a molecular sieve and perlite, and adding a proper amount of polyethylene glycol aqueous solution while rolling and forming, wherein the addition amount of polyethylene glycol accounts for 1wt% of the total weight of the molecular sieve and the pearls Dan Ganji; the amount of the polyethylene glycol aqueous solution is 20wt% of the total weight of the molecular sieve and the pearl Dan Ganji.

The pellets are dried and then screened, and the pellets with the diameter of 0.3-1 mm are taken and baked for 1 hour at 950 ℃ to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

And (3) contacting the crystallized pellets with a barium acetate solution for cation exchange.

Example 4

Preparing 5wt% sodium polystyrene sulfonate aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of the flocculant solution to the molecular sieve is 5:1. after standing for 60 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 120 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the halloysite is 95:5;

mixing a molecular sieve and halloysite, and adding a proper amount of sodium carbonate aqueous solution while rolling and forming, wherein the addition amount of sodium carbonate accounts for 4wt% of the total weight of the molecular sieve and the halloysite dry basis; the amount of the sodium carbonate aqueous solution is 15wt% of the total weight of the molecular sieve and halloysite dry basis.

And (3) drying the pellets, screening, taking the pellets with the diameter of 0.3-1 mm, and roasting at 900 ℃ for 1 hour to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

Example 5

Preparing 8wt% sodium lignin sulfonate aqueous solution, adding a Raw-NaKX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of the flocculant solution to the molecular sieve is 13:1. after standing for 20 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 110 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the kaolin is 90:10;

uniformly stirring a molecular sieve and kaolin, and adding a proper amount of polyethylene glycol aqueous solution while rolling and forming to form pellets; the addition amount of the polyethylene glycol accounts for 1 weight percent of the total weight of the molecular sieve and the kaolin dry basis. The amount of the polyethylene glycol aqueous solution is 20 weight percent of the total weight of the molecular sieve and the kaolin dry basis;

And (3) baking the pellets, and taking the pellets with the diameter of 0.3-1 mm, and roasting at 800 ℃ for 2 hours to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

Example 6

Preparing a 4wt% polyacrylamide aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of a flocculant solution to the molecular sieve is 8:1. after standing for 90 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 100 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the bentonite is 86:14;

uniformly stirring a molecular sieve and bentonite, adding starch accounting for 2wt% of the total weight of the molecular sieve and bentonite dry basis, fully uniformly stirring, rolling for forming, and sieving to obtain small balls with the diameter of 0.3-1 mm after drying;

roasting the pellets at 700 ℃ for 4 hours to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

Example 7

Preparing 6wt% sodium polystyrene sulfonate water solution, adding Raw-NaX molecular sieve

Fully and uniformly mixing, wherein the volume ratio of the flocculant solution to the molecular sieve is 10:1. after standing for 15 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 110 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the halloysite is 92:8;

uniformly stirring a molecular sieve and halloysite, adding lignin accounting for 3wt% of the total weight of the molecular sieve and the halloysite dry basis, fully stirring uniformly, rolling for forming, drying, sieving to obtain small balls with the diameter of 0.3-1 mm, and roasting at 725 ℃ for 3 hours to obtain an adsorbent precursor.

Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

Example 8

Preparing a 2wt% sodium lignin sulfonate aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of a flocculant solution to the molecular sieve is 4:1. after standing for 50 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 120 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the kaolin is 88:12;

uniformly stirring a molecular sieve and kaolin, and adding a proper amount of sodium carbonate aqueous solution while rolling and forming, wherein the addition amount of sodium carbonate is 5wt% of the total weight of the molecular sieve and kaolin dry basis; the amount of the aqueous sodium carbonate solution was 20wt% based on the total weight of molecular sieve and kaolin dry basis.

And (3) drying the pellets, screening, taking the pellets with the diameter of 0.3-1 mm, and roasting at the temperature of 650 ℃ for 5 hours to obtain the adsorbent precursor.

Comparative examples 1 to 1

The relevant parameters involved in the preparation of the adsorbent in this comparative example were the same as in example 1, except that the NaX molecular sieve selected was a large particle size NaX molecular sieve. Preparing a 1wt% polyacrylamide aqueous solution, adding a large-particle-size NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of a flocculant solution to the molecular sieve is 15:1. after standing for 30 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 90 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The procedure is as in example 1.

The electron microscopy result of the selected large-particle NaX molecular sieve is shown in FIG. 2, and the D90 of the selected large-particle NaX molecular sieve is 2.5 μm.

The bulk density, mechanical strength and adsorption capacity of the final adsorbent obtained are shown in Table 1.

Comparative examples 1 to 2

The relevant parameters involved in the preparation of the adsorbent in this comparative example are the same as in example 2, except that:

the NaKX molecular sieve was not treated with a flocculant solution (10 wt% aqueous polydimethyldiallylammonium chloride solution).

Directly mixing the Raw-NaKX molecular sieve and bentonite, and then adding lignin to prepare the final adsorbent.

Comparative examples 1 to 3

The adsorbents A-B were prepared in this comparative example, and the parameters related to the preparation were the same as in example 1, except that:

adsorbent a: after the flocculant solution contacts with the molecular sieve, standing treatment is not performed; the procedure is as in example 1.

Adsorbent B: after the flocculant solution is contacted with the molecular sieve, standing for 24 hours; the procedure is as in example 1.

The bulk density, mechanical strength and adsorption capacity of the finally obtained adsorbents A to B are shown in Table 1.

Comparative examples 1 to 4

The adsorbents C-D were prepared in this comparative example, and the parameters related to the preparation were the same as in example 1, except that:

Adsorbent C: the molecular sieve was treated with 0.5wt% flocculant solution, with the remainder being as in example 1.

Adsorbent D: the molecular sieve was treated with 15wt% flocculant solution, the remainder being the same as in example 1.

The bulk density, mechanical strength and adsorption capacity of the final adsorbent C-D are shown in Table 1.

Comparative examples 1 to 5

The relevant parameters involved in the adsorbent preparation process in this comparative example are the same as in example 1, except that:

the molecular sieve and the flocculant solution were mixed, allowed to stand, centrifugally separated, dried in an oven at 200 ℃ and crushed by a crusher to obtain a molecular sieve with closely packed crystal grains, and the rest is the same as in example 1.

Example 9

Bulk density, mechanical strength and adsorption capacity test results. The adsorbents were tested for bulk density, mechanical strength and adsorption capacity as described above, and the results are shown in table 1.

TABLE 1 bulk Density, mechanical Strength and adsorption Capacity of samples

As can be seen from Table 1, in examples 1 to 8, the repulsive force between the grains is eliminated after the Raw-molecular sieve is treated by the flocculant solution, so that the grains are closely packed, and the prepared adsorbent has higher bulk density and mechanical strength. In comparative example 1-1, the adsorbent prepared by the large particle size molecular sieve was low in adsorption capacity due to mass transfer limitations. In comparative examples 1-2, the Raw-molecular sieve was not treated with a flocculant, the gaps between the grains were large, and the prepared adsorbent had a low bulk density and poor mechanical strength. In comparative examples 1-3-A, the molecular sieve and the flocculant solution were stirred uniformly, and then centrifuged without standing, and the flocculant did not sufficiently act, and the flocculation effect was poor, and the bulk density of the prepared adsorbent was low. In comparative examples 1-3-B, the standing time after flocculation was too long, the flocculant was partially degraded, the flocculation effect was poor, and the bulk density of the prepared adsorbent was low. In comparative examples 1 to 4 to C, too low a concentration of the flocculant resulted in poor flocculation. In comparative examples 1-4-D, the concentration of the flocculant was too high, the viscosity of the system after the flocculant and the molecular sieve were mixed was large, the mixing was uneven, and the flocculation effect was slightly poor. In comparative examples 1 to 5, too high a drying temperature resulted in partial degradation of the flocculant and poor flocculation effect.

Example 10

Preparing a 1wt% polyacrylamide aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of the flocculant solution to the molecular sieve is 5:1; after standing for 30 minutes, the molecular sieve and the flocculant solution are centrifugally separated, dried in a baking oven at 120 ℃, and crushed by a crusher to obtain the molecular sieve with crystal grains closely packed.

The ratio of the molecular sieve to the kaolin is 85:15;

uniformly stirring a molecular sieve and kaolin, and adding a proper amount of polyethylene glycol aqueous solution while rolling and forming to form pellets; the addition amount of the polyethylene glycol accounts for 1 weight percent of the total weight of the molecular sieve and the kaolin dry basis; the amount of the polyethylene glycol aqueous solution is 20wt% of the total weight of the molecular sieve and the kaolin dry basis.

And (3) drying the pellets, screening, taking the pellets with the diameter of 0.3-1 mm, and roasting at 600 ℃ for 6 hours to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

Filling the crystallized pellets into a stainless steel tube type container, and introducing 0.1mol/L ammonium chloride solution until the sodium content in the outlet solution is lower than 0.1wt%. Exchange temperature 60 ℃ and volume space velocity 5h ^-1 . Washing with deionized water to neutral pH, and oven drying at 100deg.C to obtain NH ₄ X pellets.

NH is added to ₄ The X pellets were turned over while spraying a barium chloride solution at a concentration of 0.1mol/L until the pellets were completely wetted (brought into contact with the pellets in the form of spray droplets), allowed to stand for 30 minutes, dried and calcined at 500 ℃ for 1 hour.

The prepared p-xylene adsorbent had a barium exchange degree of 98.6% and its bulk density, mechanical strength and adsorption capacity are shown in table 2.

Example 11

Preparing a 2wt% sodium polyacrylate aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of a flocculant solution to the molecular sieve is 8:1; after standing for 20 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 120 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the bentonite is 88:12;

uniformly stirring a molecular sieve and bentonite, and adding a proper amount of sodium carbonate aqueous solution while rolling and forming to form pellets; the addition amount of the sodium carbonate accounts for 3wt% of the total weight of the molecular sieve and the bentonite dry basis; the amount of the sodium carbonate aqueous solution is 15wt% of the total weight of the molecular sieve and bentonite dry basis.

And (3) drying the pellets, screening, taking the pellets with the diameter of 0.3-1 mm, and roasting at the temperature of 700 ℃ for 4 hours to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

Filling the crystallized pellets into a stainless steel tube type container, and introducing 0.15mol/L ammonium chloride solution until the sodium content in the outlet solution is lower than 0.1wt%. Exchange temperature 80 ℃ and volume space velocity 2h ^-1 . Washing with deionized water to neutral pH, and oven drying at 100deg.C to obtain NH ₄ X pellets.

NH is added to ₄ The X pellets were turned over while spraying a barium chloride solution at a concentration of 0.15mol/L until the pellets were completely wetted (brought into contact with the pellets in the form of spray droplets), left to stand for 60 minutes, dried and calcined at 350 ℃ for 5 hours.

The prepared p-xylene adsorbent had a barium exchange degree of 99.1% and a bulk density, mechanical strength and adsorption capacity as shown in Table 2.

Example 12

Preparing a 6wt% sodium polystyrene sulfonate aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of a flocculant solution to the molecular sieve is 6:1; after standing for 60 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 120 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the halloysite is 92:8;

mixing the molecular sieve and halloysite, adding lignin accounting for 3wt% of the total weight of the molecular sieve and the halloysite dry basis, fully and uniformly stirring, and then rolling and forming.

And (3) drying the pellets, screening, taking the pellets with the diameter of 0.3-1 mm, and roasting at 725 ℃ for 3 hours to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

Filling the crystallized pellets into a stainless steel tube type container, and introducing 0.3mol/L ammonium chloride solution until the sodium content in the outlet solution is lower than 0.1wt%. Exchange temperature 70 ℃ and volume space velocity 3h ^-1 . Washing with deionized water to neutral pH, and oven drying at 100deg.C to obtain NH ₄ X pellets.

NH is added to ₄ The X pellets are turned over while spraying barium nitrate solution with the concentration of 0.05mol/L until the pellets are completely wetted (the pellets are contacted with the X pellets in the form of spray droplets), and the X pellets are left stand for 90 minutes and are baked for 2 hours at 450 ℃ after being dried.

The prepared p-xylene adsorbent had a barium exchange degree of 98.9% and its bulk density, mechanical strength and adsorption capacity are shown in table 2.

Comparative example 2-1

The relevant parameters involved in the preparation of the adsorbent in this comparative example were the same as in example 10, except that the preparation method was different, specifically as follows:

uniformly stirring a Raw-NaX molecular sieve and kaolin which are treated by polyacrylamide and have crystal grains closely piled, and adding a proper amount of polyethylene glycol aqueous solution while rolling and forming to form pellets;

drying the pellets, and roasting to obtain an adsorbent precursor; crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets; ammonium exchanging the crystallized pellets to obtain NH ₄ X pellets.

NH is added to ₄ The X pellets are directly put into a barium chloride solution, and the solution is gently stirred until the solution is completely absorbed by the pellets, wherein the amount of the barium chloride solution is NH ₄ Saturated water absorption of the X pellets. Standing, drying and roasting to obtain the adsorbent.

The resulting adsorbents had a barium exchange of 86.2 to 103.7wt% due to the non-uniform distribution of the barium solution, and the bulk density, mechanical strength and adsorption capacity are shown in Table 2.

Comparative examples 2 to 2

NH is added to ₄ The X pellets are turned over and sprayed with barium chloride solution until the pellets are fully wetted (the pellets are contacted with the X pellets in the form of spray droplets), and then the X pellets are directly dried and roasted without standing treatment to obtain the adsorbent.

The prepared p-xylene adsorbent had a barium exchange degree of 98.5% and a bulk density, mechanical strength and adsorption capacity as shown in Table 2.

TABLE 2 bulk Density, mechanical Strength and adsorption Capacity of each sample

Remarks: a refers to the molar amount of barium salt required to prepare 100g of the adsorbent; b refers to the molar amount of barium salt in the waste liquid produced by preparing 100g of the adsorbent.

Comparative example 2-1 was not sprayed with the barium solution but pellets were directly placed in the barium solution, and the liquid was unevenly distributed to cause uneven barium distribution.

Comparative example 2-2 was not subjected to the standing treatment, and the barium solution was not sufficiently diffused into the pore channels of the molecular sieve, resulting in uneven barium distribution, high barium content at the outer surface of the pellets and low barium content at the inner portion.

Example 13

Preparing a 2wt% polyacrylamide aqueous solution, adding a Raw-NaX molecular sieve, and fully and uniformly mixing, wherein the volume ratio of the flocculant solution to the molecular sieve is 7:1; after standing for 30 minutes, centrifugally separating the molecular sieve and the flocculant solution, drying in a baking oven at 100 ℃, and crushing by a crusher to obtain the molecular sieve with closely packed crystal grains.

The ratio of the molecular sieve to the kaolin is 85:15;

And baking the pellets at 600 ℃ for 4 hours to obtain the adsorbent precursor. Crystallizing the adsorbent precursor in alkali liquor to obtain crystallized pellets.

Filling the crystallized pellets into a stainless steel tube type container, and introducing 0.2mol/L ammonium chloride solution until the sodium content in the outlet solution is lower than 0.1wt%. Exchange temperature 70 ℃ and volume space velocity 3h ^-1 . Washing with deionized water to neutral pH, and oven drying at 100deg.C to obtain NH ₄ X pellets.

NH is added to ₄ The X pellets are turned over and sprayed with lithium chloride solution with the concentration of 0.05mol/L until the pellets are completely wetted (the pellets are contacted with the X pellets in the form of spray droplets), the X pellets are stood for 30 minutes, and the LiX adsorbent is obtained after drying and roasting for 1 hour at 500 ℃.

Claims

1. A preparation method of an adsorbent is characterized in that,

the adsorbent is loaded with metal ions;

the preparation method comprises the following steps:

s1, raw-molecular sieve treatment:

the Raw-molecular sieve is contacted with a flocculating agent to form a solution, and then the solution is dried and crushed to obtain a treated molecular sieve; the particle size D90 of the Raw-molecular sieve is not more than 1.5 mu m;

the Raw-molecular sieve is a molecular sieve which is not treated by a flocculating agent;

s2, preparing an adsorbent precursor:

The binder comprises one or more of kaolin, bentonite, perlite and halloysite;

s3, crystallization treatment

Crystallizing the adsorbent precursor in an alkaline system;

s4. Metal ion Loading

2. The method for producing an adsorbent according to claim 1, wherein,

s1, after a Raw-molecular sieve is contacted and mixed with a flocculating agent to form a solution, standing treatment is carried out, and then precipitate is separated out for drying and crushing treatment;

the standing treatment time is not less than 10min.

3. The method for producing an adsorbent according to claim 2, wherein,

the separation mode is centrifugal separation, and the centrifugal rotating speed is not lower than 2000r/min.

4. The method for producing an adsorbent according to claim 1, wherein,

in S1, the drying temperature is not more than 150 ℃.

5. The method for producing an adsorbent according to claim 1, wherein,

the flocculant comprises one or more of polyacrylamide, polydimethyl diallyl ammonium chloride, sodium polyacrylate, sodium polystyrene sulfonate and sodium lignin sulfonate.

6. The method for producing an adsorbent according to any one of claims 1 to 5, characterized in that,

s1, preparing the flocculant into an aqueous solution with the concentration of 1-10wt%, and then contacting with a Raw-molecular sieve;

the volume ratio of the flocculant solution to the Raw-molecular sieve is (2-15): 1.

7. the method for producing an adsorbent according to any one of claims 1 to 5, characterized in that,

in S1, the ratio of the addition mass of the flocculant to the addition mass of the Raw-molecular sieve is (0.05-1): 1.

8. the method for producing an adsorbent according to claim 1, wherein,

s2, the addition amount of the molecular sieve is higher than that of the binder;

the addition amount of the pore-forming agent is 1-5wt% of the total weight of the molecular sieve and the binder dry basis.

9. The method for producing an adsorbent according to claim 1, wherein,

s2, the temperature of high-temperature treatment is 550-950 ℃; the treatment time of the high-temperature treatment is 1-8 hours.

10. The method for producing an adsorbent according to any one of claims 1 to 5, characterized in that,

and S4, directly contacting the crystallized product with a solution containing target metal ions, and carrying out cation exchange to realize the loading of the target metal ions, thereby obtaining the adsorbent product loaded with the metal.

11. The method for producing an adsorbent according to claim 6, wherein,

the S4 specifically comprises

then, the solution is contacted with a solution containing target metal ions to realize the loading of the target metal ions, and the adsorbent product loaded with the metal is obtained;

determining the saturated water absorption of the product after the ammonium ion exchange treatment, wherein the amount of the solution containing the target metal ions does not exceed the saturated water absorption of the product.

12. The method for producing an adsorbent according to claim 11, wherein,

the addition concentration of the ammonium salt is 0.05-0.3 mol/L.

13. The method for producing an adsorbent according to claim 11, wherein,

placing the crystallized product in a container, and continuously introducing a solution containing ammonium ions into the container;

wherein the container is provided with a liquid inlet and a liquid outlet;

the volume airspeed of the ammonium salt solution is 2-8 h ^-1 。

14. The method for producing an adsorbent according to claim 11, wherein,

and enabling the solution containing target metal ions to be atomized into small liquid drops to be in contact with the product after the ammonium ion exchange treatment, then standing for treatment, and finally drying and carrying out high-temperature treatment.

15. The method for producing an adsorbent according to claim 14, wherein,

the standing treatment time is 30-120 min;

the temperature of the high-temperature treatment is 350-500 ℃; the time of the high-temperature treatment is 1-5 hours.

16. An adsorbent prepared by a method according to any one of claims 1 to 15,

the adsorbent comprises metal ions and a molecular sieve;

the adsorbent has a particle size of not less than 600 kg/m ³ Is of the bulk density of (2)。

17. The adsorbent prepared by any one of claims 1 to 15 or the use of the adsorbent of claim 16, wherein:

the method is used for obtaining a target product from the mixture through adsorption separation;

the target product comprises any one or two of paraxylene and paracresol.