CN110523380B - A kind of honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent and its in-situ synthesis method - Google Patents

Abstract

The invention discloses a honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent and an in-situ synthesis method thereof. The method comprises the following steps: uniformly mixing fumaric acid, an alkaline substance and water, adding a thickening agent, uniformly mixing to obtain a mixed solution, soaking the honeycomb ceramic matrix blank in the mixed solution, and drying to obtain a blank containing deprotonated fumaric acid; and (3) soaking the embryo body containing deprotonated fumaric acid in an aluminum salt solution, heating in a water bath, cooling to room temperature, filtering to obtain a precipitate, washing, drying, heating, and performing sintering activation treatment to obtain the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent. According to the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent provided by the invention, the adsorption active substances are uniformly and compactly distributed on the honeycomb ceramic fiber blank, and the loading amount is high; the adsorbent has low crystallization temperature and high crystallization rate; the product is S-shaped water vapor adsorption isothermal, has the characteristics of high adsorption rate, high equilibrium adsorption capacity, easy desorption and the like, and can be applied to preparation of adsorption type dehumidification rotating wheels or total heat recoverers.

Description

A kind of honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent and its in-situ synthesis method

technical field

The invention belongs to the field of gas adsorption drying purification and heat recovery, in particular to an in-situ synthesis method of a honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent.

Background technique

The honeycomb ceramic-based dehumidification adsorbent, which is constructed by organically combining ceramic fibers and adsorbents, can be used in adsorption dehumidification rotors and total heat recovery systems. Among them, the dehumidification rotor core (block adsorbent) is the core of the system, and its performance determines the energy efficiency of the system. The evaluation of the performance of the dehumidifying rotor mainly includes two aspects: (1) The performance of the adsorbent itself: the adsorbent has a higher equilibrium adsorption capacity; and a lower desorption temperature. (2) Composite process of adsorbent and substrate: The adsorbent is closely combined with the honeycomb substrate to prevent the adsorbent from falling off; it has a high adsorbent loading to improve the adsorption performance of the block adsorbent.

Aluminum-fumarate metal-organic framework (MOF) adsorbent with high saturated adsorption capacity (above 0.4 g/g), good thermal stability, S-type water vapor adsorption isotherm, and low desorption temperature (about 70 °C) )Features. The dehumidification rotor (dehumidification rotor core or block adsorbent) made of it has a large dehumidification capacity and can be regenerated by using low-grade heat sources such as solar energy and industrial waste heat. The existing honeycomb ceramic-based block adsorbents mainly include silica gel, molecular sieve, etc. Silica gel is mainly used in high humidity environments; it has a lower desorption temperature (150°C), but the adsorption capacity at low humidity or higher temperature is quite low (below 5%). Silicate molecular sieves, such as NaA, 13X, etc., show extremely strong hygroscopic ability, but the dehumidification rotating core made of them is still insufficient: (1) The equilibrium adsorption capacity of molecular sieves is low (usually below 0.25g/g); (2) ) The molecular sieve regeneration temperature is high (above 200 ℃), which is not conducive to the energy saving of the system; (3) In the preparation process, the honeycomb body made of ceramic or glass fiber paper is usually used as the base material, and the industrial molecular sieve (granule) with larger particle size is used as the base material. 2-5 μm in diameter) is an adsorbent, which is formed by dipping and coating on the premise of adding inorganic glue or organic/inorganic composite glue without adsorption capacity as a binder. For example, US patent US 4886769 "active gas adsorption unit and manufacturing method", Chinese patent ZL 200610123763.0 "the preparation method of molecular sieve/modified silica gel composite block adsorbent" involves the preparation process of molecular sieve adsorbent. On the one hand, the addition of the binder will block the pores of the molecular sieve and reduce the dehumidification capacity of the adsorbent; Increasing the amount of glue hanging will cause the adsorbent to drop powder). Therefore, it is particularly important to prepare a new type of dehumidification rotor (block adsorbent) with high dehumidification capacity, high glue hanging capacity and lower regeneration temperature to improve system efficiency.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent and an in-situ synthesis method thereof.

The in-situ synthesis method of a honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent provided by the invention is a kind of adsorbent with high loading capacity, high equilibrium adsorption capacity, fast adsorption rate, and between the adsorbent and the common fiber. In situ synthesis method of a novel honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent with strong effect.

The object of the present invention is achieved by at least one of the following technical solutions.

The in-situ synthesis method of a honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent provided by the invention comprises the following steps:

(1) Impregnation of the honeycomb ceramic base body: Mix fumaric acid, alkaline substances (fumaric acid and alkaline substances as basic raw materials) and water (water as solvent) at room temperature, stir evenly, and then add increasing Thickening agent (preferably a hydrophilic polymer can be used as thickening agent), mix well to obtain a mixed solution, immerse the honeycomb ceramic base embryo in the mixed solution (clear and transparent solution), take it out and dry it to obtain a solution containing Embryos of protonated fumaric acid;

(2) In situ synthesis of honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent: the embryo body containing deprotonated fumaric acid described in step (1) was immersed in an aluminum salt solution, and heated in a water bath (ie, in situ). Crystallization reaction, temperature is 30-80 ° C, time is 20-120 min), cooled to room temperature, filtered to get the precipitate, washed, dried, heated for sintering activation treatment, to obtain the honeycomb ceramic-based aluminum-fumaric acid MOF adsorption agent.

Further, the alkaline substance in step (1) is an inorganic alkaline substance or an organic alkaline substance; the alkaline substance is sodium hydroxide, potassium hydroxide, ammonia water, methylamine, ethylamine, propylamine, butylamine, One or more of diethylamine, dipropylamine and dibutylamine; the molar ratio of the basic substance and fumaric acid is 2.5-4.0:1; the molar ratio of the water and fumaric acid is 4-120: 1. In step (1), the alkaline substance is added to protonate the fumaric acid, thereby reducing the crystallization temperature of aluminum-fumaric acid; the fumaric acid has a high degree of protonation and a large drop in the crystallization reaction temperature.

Preferably, the molar ratio of the alkaline substance and fumaric acid in step (1) is 3.0-3.8:1.

Preferably, the molar ratio of water and fumaric acid in step (1) is 60-100:1.

Preferably, the alkaline substance in step (1) is one or both of sodium hydroxide and potassium hydroxide. Because ammonia and organic amines have certain volatility, toxicity and high price, etc., inorganic strong bases (sodium hydroxide and potassium hydroxide) are preferred.

In step (1), certain fumaric acid and alkali are added as basic raw materials in the production of deprotonated fumaric acid honeycomb ceramic base body, and water is used as solvent; the molar ratio of fumaric acid/alkali/water is 1.0/2.5 ~4.0/40~120. Theoretically, according to the structure of the aluminum-fumaric acid MOF product, the molar ratio of fumaric acid and base is 1/2. In order to improve the degree of protonation of fumaric acid, the alkali added is excessive; and the excess alkali can increase the viscosity of the mixed solution A, which is convenient for the loading of deprotonated fumaric acid in the honeycomb ceramic fiber embryo; Similarly, the amount of added solvent water is small , the viscosity of the system is large, which is convenient for the deprotonated fumaric acid loading of the embryo body; but too little water is added, and the deprotonated fumaric acid is not uniformly loaded on the surface of the ceramic fiber embryo body; on the contrary, if the amount of water added is large, the viscosity of the system Small, unfavorable for embryo body loading.

Further, the thickener described in step (1) is one or more of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP) and sodium carboxymethyl cellulose (CMC), etc.; the quality of the thickener It accounts for 0.1wt%-1wt% of the mass of the mixed solution.

Preferably, the mass of the thickener in step (1) accounts for 0.3-0.6% of the mass of the mixed solution.

Step (1) A small amount of hydrophilic polymer is added as a thickener in the preparation of the deprotonated fumaric acid honeycomb ceramic base body, the purpose of which is to increase the amount of glue attached to the deprotonated fumaric acid by the honeycomb ceramic base body. , thereby synthesizing a honeycomb ceramic-based adsorbent with more target products. Hydrophilic polymers include polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), sodium carboxymethylcellulose (CMC), and the like. The added amount accounts for 0.1-1% of the mass of the mixed solution A; the added thickener is less, and the viscosity increasing effect is not obvious; the added amount is large; the viscosity of the mixed solution A is high, and the deprotonated fumaric acid coated on the embryo body is The amount is high, but the distribution is uneven; preferably, it accounts for 0.3-0.6% of the mass of the mixed solution A.

Further, the drying temperature in step (1) is 30-100° C., and the drying time is 3-12 h.

If the drying temperature is low and the drying time is short, the formed deprotonated fumaric acid embryo has a loose structure, and the formed adsorption active substance has a weak interaction force with the substrate; if the drying temperature is high and the drying time is long, the formed The protonated fumaric acid embryo body has a dense structure, and it is difficult for aluminum salts to enter the embryo body for crystallization reaction. The crystallization time is long and the product is defective. Therefore, preferably, the drying temperature in step (1) is 50-80° C., and the drying time is 5-10 h.

Further, the preparation of the honeycomb ceramic base body in step (1) includes: hot-rolling the flat paper and the face paper of the fiber paper with the sizing material on the corrugating roll and the flat roll of the corrugating machine, respectively, and pasting them into single-sided corrugated paper Then, under the action of the sizing material, it is rolled into a honeycomb ceramic matrix core body, the surface of which is cut and polished, heated for sintering treatment, and organic matter is removed to obtain the honeycomb ceramic matrix body.

In the present invention, ceramic fiber paper is used as the base material, and the process of coating, hot pressing, rolling and sintering is carried out to form a honeycomb ceramic base body, and the honeycomb ceramic body is dried in an oven before being tested and used. spare. Since the ceramic fiber paper is only used as a carrier, other inorganic carriers such as glass fiber paper can also be used as the carrier, which has no effect on the synthesis and performance of the bulk adsorbent.

Further, in the preparation process of the honeycomb ceramic matrix body, the fiber paper can be one of ceramic fiber paper and glass fiber paper; the sizing material is more than one of inorganic glue and organic glue; The inorganic glue is one of silica sol (SiO ₂ ), aluminum sol (Al ₂ O ₃ ), titanium sol (TiO ₂ ), and zirconium sol (ZrO ₂ ); the organic glue is polyvinyl acetate ( One of VAE), polyvinyl alcohol glue (PVA), acrylate and organosilicon modified acrylate; the temperature of the sintering treatment is 350-700°C, and the sintering treatment time is 10-24h.

Preferably, in the preparation process of the honeycomb ceramic base body, the temperature of the sintering treatment is 400-600° C., and the time of the sintering treatment is 12-18 h.

Further preferably, in the preparation process of the honeycomb ceramic base body, the temperature of the sintering treatment is 500° C.; the time of the sintering treatment is 16 hours.

Further, in the preparation process of the honeycomb ceramic base body, adding sizing material is convenient for forming corrugated paper and rewinding; organic glue can improve its toughness; inorganic glue can improve its heat resistance and rigidity; a single sizing material forms The honeycomb ceramic matrix body has a loose structure and low strength; therefore, preferably, the sizing material adopts organic/inorganic composite glue (that is, organic glue and inorganic glue are used in combination), such as SiO ₂ and VAE, Al ₂ O ₃ and VAE, Any one of the four combinations of SiO ₂ and PVA, Al ₂ O ₃ and PVA, or two or more of the above-mentioned sizing materials are used in combination.

Further, the aluminum salt solution in step (2) is a uniform mixture of aluminum salt and water; the aluminum salt is one or more of aluminum sulfate, aluminum nitrate, aluminum chloride, and aluminum potassium sulfate, etc.; the aluminum The mass percentage concentration of the salt solution is 5wt%-20wt%.

Preferably, the aluminum salt in step (2) is one or more of aluminum sulfate and aluminum nitrate.

Preferably, the concentration of the aluminum salt solution in step (2) is 8-15%.

Step (2) In the in-situ synthesis of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent, the deprotonated fumaric acid embryo body is dipped in an aluminum salt solution, and the aluminum salt used includes aluminum sulfate, aluminum nitrate, aluminum chloride and One or more of crystalline salts such as aluminum potassium sulfate. From the corrosiveness of aluminum salts, the source of raw materials, and the elimination of impurity cations as much as possible on the crystal purity of the adsorbent.

Step (2) In the in-situ crystallization synthesis of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent, the mass concentration of the added aluminum salt solution is 5-20%. The high concentration of aluminum salts migrates rapidly to the embryo body, which is beneficial to the in-situ crystallization reaction of aluminum-fumaric acid, but if the concentration is too high, the crystallinity of the crystallization reaction product decreases, and the dispersion of crystals on the embryo body is uneven; the same , the aluminum salt concentration is low, and the migration speed to the embryo body is slow, which is not conducive to the in-situ crystallization reaction of aluminum-fumaric acid, preferably 8-15%;

Further, the temperature of the water bath heating treatment in step (2) is 30°C-80°C, and the time of the water bath heating treatment is 20-120 min.

Preferably, the temperature of the water bath heating treatment in step (2) is 40-70° C., and the time of the water bath heating treatment is 40-80 min.

Step (2) In the in-situ crystallization synthesis of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent, the reaction is carried out in a water bath at 30-80° C. for 20-120 min. If the temperature is too low, the reaction rate of aluminum-fumaric acid on the glass fiber is too slow, so that the load of aluminum-fumaric acid on the glass fiber is too small; if the temperature is too high, the reaction rate of aluminum-fumaric acid on the glass fiber is too low. The rate is so fast that the aluminum-fumaric acid falls off. The crystallization time also has the same problem. If the time is too short, the loading of aluminum-fumaric acid on the glass fiber will be too small; if the time is too long, the aluminum-fumaric acid will fall off. Preferably, the reaction is carried out in a water bath at 40-70°C for 40-80 minutes.

Further, the temperature of the sintering and activation treatment in step (2) is 345-355° C., and the time of the sintering and activation treatment is 6-12 h.

Preferably, the temperature of the sintering activation treatment in step (2) is 350°C.

Preferably, the drying temperature in step (2) is 150° C., and the drying time is 12-24 h.

The present invention provides a honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent prepared by the above-mentioned preparation method.

In the in-situ synthesis method provided by the invention, a honeycomb embryo body made of ceramic fiber paper is used as the base material, and the reactant (deprotonated fumaric acid) of the self-reactive raw material fumaric acid and alkali is used as an adhesive; The body is immersed in a mixed solution containing deprotonated fumaric acid, and under the thickening of a water-soluble polymer, a honeycomb embryo body containing deprotonated fumaric acid is formed; the embryo body is placed in the reaction solution of aluminum salt to crystallize , after washing and drying, a honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent was prepared; the prepared honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent was a bulk adsorbent (dehumidifying core), which can be applied to Assembled in adsorption dehumidification rotor or total heat recovery device.

Taking sodium hydroxide as the deprotonation reagent as an example below, the working principle of the method of the present invention is described:

Taking the honeycomb ceramic fiber embryo body as the base material, through the impregnation method, with the aid of the tackifier water-soluble polymer, the sodium fumarate alkaline mixture is first impregnated on the embryo body. Therefore, it can form a honeycomb ceramic fiber body with uniform loading of sodium fumarate; due to deprotonation, sodium fumarate and aluminum salts can be relatively Crystallization reaction occurs at low temperature; when the embryo body containing sodium fumarate is immersed in the aluminum salt reaction solution, the sodium ions in the sodium fumarate and the aluminum ions in the reaction solution will undergo ion exchange, and the aluminum ions will be transferred to the ceramic fiber. The embryo body migrates, and the sodium ions migrate to the aluminum salt solution. Under a certain water bath temperature and reaction time, the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent can be formed.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) the in-situ synthesis method provided by the invention, due to the adsorption characteristics of the aluminum-fumaric acid MOF adsorbent itself, the obtained honeycomb ceramic base aluminum-fumaric acid MOF adsorbent has higher adsorption performance ( Measured by the equilibrium adsorption capacity), the equilibrium adsorption capacity can reach 30-36%, and the lower desorption temperature (that is, the desorption activation energy), the desorption temperature can reach 60-80 ℃;

(2) In the in-situ synthesis method provided by the present invention, since it is an in-situ generation of an aluminum-fumaric acid adsorbent, no additional inorganic adhesive or inorganic/organic composite adhesive (the organic high polymer added in the mixed solution A is added to increase the viscosity) is added. The adsorbent has been eliminated in the activation process), so that the adsorbent generated in situ has a high loading capacity, and its loading capacity can reach 65-75%, and the maximum loading capacity can reach 75.97%, which is much higher than the existing molecular sieve loading capacity (below 45%);

(3) In the in-situ synthesis method provided by the present invention, compared with the preparation of the bulk adsorbent by the binder method, the in-situ synthesis method has a strong force between the crystal grains of the adsorbent synthesized by the in-situ synthesis method and between the ceramic fibers and is not easy to occur The phenomenon of powder drop of adsorbent.

Description of drawings

Fig. 1 is the XRD spectrum of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent provided in Example 1 and the aluminum-fumaric acid adsorbent powder of Comparative Example;

Fig. 2 is the SEM image of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent provided in Example 1 and the aluminum-fumaric acid adsorbent powder of Comparative Example;

3 is the static water adsorption curve of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent provided in Example 1 and the aluminum-fumaric acid powder of Comparative Example;

Fig. 4 is the dynamic isothermal water adsorption curve of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent provided by the present invention.

Detailed ways

The specific implementation of the present invention will be further described below with reference to the accompanying drawings and embodiments, but the implementation and protection of the present invention are not limited thereto. It should be pointed out that, if there are any processes that are not described in detail below, those skilled in the art can realize or understand them with reference to the prior art. If the reagents or instruments used do not indicate the manufacturer, they are regarded as conventional products that can be purchased in the market.

Comparative example

At room temperature and under magnetic stirring, take a 500mL beaker, add 23.2g fumaric acid, 26.0g sodium hydroxide, and 300ml deionized water to the beaker according to the molar ratio of fumaric acid/alkali/water to 1.0/3.25/83 , after the raw materials are dissolved and stirred evenly, add 2.0g of PVA powder (polyvinyl alcohol), continue to stir to obtain a clear and transparent solution A, the mass of the added PVA powder accounts for 0.5wt% of the mass of the clear and transparent solution A; another 500ml Dissolve 66.6g of Al ₂ (SO ₄ ) ₃ ·18H ₂ O in 300ml of deionized water in a beaker, stir until dissolved to form solution B (the mass percentage concentration of solution B is 9.33%); The solution B was evenly mixed, and it was placed in a 60°C water bath and heated for 60 min to obtain a suspension containing a white precipitate; then the suspension containing the white precipitate was centrifuged to obtain a white precipitate and washed twice with deionized water. Dry at 150 °C for 16 h, and then activate at 350 °C for 8 h to obtain aluminum-fumaric acid adsorbent powder.

Example 1

(1) Preparation of honeycomb ceramic body: 23g/m ² quantitative ceramic fiber paper (the mass ratio of flat paper and face paper is 1:1) was respectively applied to the corrugating roll and flat roll of the corrugating machine through the action of sizing agent , and hot-rolled (180°C) to form a single-sided corrugated paper. The composition of the rubber compound is 45wt% SiO ₂ sol and 55wt% VAE glue; The surface was cut and polished, and sintered at 500° C. for 16 hours to remove organic matter to form a honeycomb ceramic base body (the size of which was φ=4cm(D)×6cm(H)).

(2) Under room temperature and magnetic stirring, take a 500mL beaker, according to the molar ratio of fumaric acid/alkali/water to be 1.0/3.25/83, take 23.2g fumaric acid, 26.0g sodium hydroxide, 300ml deionized water and add In the beaker, after stirring evenly, add 2.0 g of PVA powder, and continue to stir to obtain a clear and transparent solution A. The mass of the added PVA powder accounts for 0.5wt% of the mass of the clear and transparent solution A; the honeycomb ceramic embryo is immersed in the clear and transparent solution A. In solution _A , take it out after it is completely wet, and dry it at 60°C for ₈ hours to form a honeycomb ceramic embryo body containing _sodium fumarate _; 300ml of deionized water, stirred until dissolved to form solution B (the mass percentage concentration of solution B is 9.33wt%); the honeycomb ceramic embryo body containing sodium fumarate is immersed in solution B, and then placed in a water bath temperature It was heated in a water bath at 60°C for 60min, cooled to room temperature, centrifuged to collect the precipitate, washed three times with deionized water, dried at 150°C for 16h, and activated at 350°C for 8h to obtain the honeycomb ceramic-based aluminum - Fumaric acid MOF adsorbent.

Example 2

(1) Preparation of honeycomb ceramic body: 23g/m ² quantitative ceramic fiber paper (the mass ratio of flat paper and face paper is 1:1) was respectively applied to the corrugating roll and flat roll of the corrugating machine through the action of sizing agent , hot-rolled (180° C.) and pasted into single-sided corrugated paper, the composition of the sizing material is 45wt% aluminum sol and 55wt% acrylate glue; then under the action of the above sizing material, the honeycomb ceramic matrix core is formed by wrapping it; The surface was cut and polished, and sintered at 700° C. for 10 hours to remove organic matter to form a honeycomb ceramic base body (the size of which was φ=4cm(D)×6cm(H)).

(2) Under room temperature and magnetic stirring, take a 500mL beaker, according to the molar ratio of fumaric acid/alkali/water to be 1.0/3.25/83, take 23.2g fumaric acid, 36.4g potassium hydroxide, 300ml deionized water and add In the beaker, after stirring evenly, add 2.0 g of PVP powder, and continue to stir to obtain a clear and transparent solution A. The mass of the added PVA powder accounts for 0.5wt% of the mass of the clear and transparent solution A; the honeycomb ceramic embryo is immersed in the clear and transparent solution A. In solution A, take it out after it is completely wet, and dry it at 50°C for 10 hours to form a honeycomb ceramic embryo body containing potassium fumarate; take another 500ml beaker, dissolve 75.0g Al(NO ₃ ) ₃ ·9H ₂ O in 400ml In deionized water, stir until dissolved to form solution B (the mass percentage concentration of solution B is 8.97% by weight); immerse the honeycomb ceramic body containing sodium fumarate in solution B, place it in a water bath temperature It was placed in a 60°C water bath for 60 minutes, cooled to room temperature, centrifuged to collect the precipitate, washed three times with deionized water, dried at 150°C for 12 hours, and then activated at 350°C for 12 hours to obtain the honeycomb ceramic-based aluminum-fumaric acid. MOF adsorbent.

Example 3

(1) Preparation of honeycomb ceramic body: 23g/m ² quantitative ceramic fiber paper (the mass ratio of flat paper and face paper is 1:1) was respectively applied to the corrugating roll and flat roll of the corrugating machine through the action of sizing agent , hot-rolled (180°C) and pasted into single-sided corrugated paper, the composition of the sizing material is 45wt% SiO ₂ sol and 55 wt% VAE glue; then under the action of the above sizing material, it is rolled to form a honeycomb ceramic matrix core; The surface was cut and polished, and sintered at 350° C. for 24 hours to remove organic matter to form a honeycomb ceramic base body (the size of which was φ=4cm(D)×6cm(H)).

(2) Under room temperature and magnetic stirring, take a 500mL beaker, according to the molar ratio of fumaric acid/alkali/water to be 1.0/3.8/100, take 23.2g fumaric acid, 42.6g potassium hydroxide, 360ml deionized water and add In the beaker, after the raw materials are dissolved and stirred evenly, 2.4g of CMC powder (sodium carboxymethyl cellulose) is added, and the stirring is continued to obtain a clear and transparent solution A. The mass of the added CMC powder accounts for 0.56wt% of the mass of the clear and transparent solution A. ; Immerse the honeycomb ceramic body in the clear and transparent solution A, take it out after it is completely wet, and dry it at 70°C for 6 hours to form a honeycomb ceramic body containing potassium fumarate; take another 500ml beaker, put 75.0g Al(NO ₃ ) ₃ ·9H ₂ O was dissolved in 300 ml of deionized water, stirred until dissolved to form solution B (the mass percentage concentration of solution B was 11.3 wt %); the honeycomb ceramic body containing sodium fumarate was dipped In solution B, put it in a water bath temperature, heat it in a 60 ℃ water bath for 60 min, cool it to room temperature, take the precipitate by centrifugation, wash it with deionized water three times, dry it at 150 ℃ for 24 hours, and then sinter it at 350 ℃ After activation for 6 h, the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent was obtained.

Example 4

(1) Preparation of honeycomb ceramic body: 23g/m ² quantitative ceramic fiber paper (the mass ratio of flat paper and face paper is 1:1) was respectively applied to the corrugating roll and flat roll of the corrugating machine through the action of sizing agent , hot-rolled (180° C.) and pasted into single-sided corrugated paper, the composition of the rubber compound is 30wt% titanium sol and 70wt% VAE glue; The surface was cut and polished, and sintered at 400° C. for 18 hours to remove organic matter to form a honeycomb ceramic base body (the size of which was φ=4cm(D)×6cm(H)).

(2) Under room temperature and magnetic stirring, take a 500mL beaker, according to the molar ratio of fumaric acid/alkali/water to be 1.0/3.0/60, take 23.2g fumaric acid, 24.0g sodium hydroxide, 216ml deionized water and add In the beaker, after the raw materials are dissolved and stirred evenly, 1.5 g of PVA powder is added, and the stirring is continued to obtain a clear and transparent solution A. The mass of the added PVA powder accounts for 0.57wt% of the mass of the clear and transparent solution A; In the clear and transparent solution A, take it out after it is completely wet, and dry it at 80°C for ₅ hours to form a honeycomb ceramic embryo body containing potassium _{fumarate ;} 18H ₂ O was dissolved in 240 ml of deionized water, stirred until dissolved to form solution B (the mass percentage concentration of solution B was 11.2 wt %); the honeycomb ceramic body containing sodium fumarate was immersed in solution B, and the It was placed in a water bath, heated in a 50°C water bath for 70 minutes, cooled to room temperature, centrifuged to collect the precipitate, washed three times with deionized water, dried at 150°C for 18 hours, and then activated at 350°C for 8 hours to obtain the honeycomb Ceramic-based aluminum-fumaric acid MOF adsorbent.

Example 5

(1) Preparation of honeycomb ceramic body: 23g/m ² quantitative ceramic fiber paper (the mass ratio of flat paper and face paper is 1:1) was respectively applied to the corrugating roll and flat roll of the corrugating machine through the action of sizing agent , hot-rolled (180°C) and pasted into single-sided corrugated paper, the composition of the rubber compound is 40wt% SiO ₂ sol and 60wt% VAE glue; then under the action of the above-mentioned rubber compound, it is rolled to form a honeycomb ceramic matrix core; The surface was cut and polished, and sintered at 500° C. for 16 h to remove organic matter to form a honeycomb ceramic base body (the size of which was φ=4cm(D)×6cm(H)).

(2) Under room temperature and magnetic stirring, take a 500mL beaker, according to the molar ratio of fumaric acid/alkali/water to be 1.0/3.5/90, take 23.2g fumaric acid, 39.2g potassium hydroxide, 324ml deionized water and add In the beaker, after the raw materials are dissolved and stirred evenly, 1.5g of CMC powder is added, and the stirring is continued to obtain a clear and transparent solution A. The mass of the added CMC powder accounts for 0.39wt% of the mass of the clear and transparent solution A; the honeycomb ceramic embryo is immersed In the clear and transparent solution A, take it out after it is completely wet, and dry it at 50 ° C for ₁₀ hours to form a honeycomb ceramic embryo body containing potassium _{fumarate ;} ·18H ₂ O was dissolved in 200 ml of deionized water, and stirred until dissolved to form solution B (the mass percentage concentration of solution B was 12.8%). The honeycomb ceramic body containing sodium fumarate was immersed in solution B, placed in a water bath temperature, placed in a water bath of 40° C. for 80 min, cooled to room temperature, centrifuged to collect the precipitate, washed three times with deionized water, After drying at 150 °C for 12 h, and then activating at 350 °C for 8 h, the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent was obtained.

Example 6

(1) Preparation of honeycomb ceramic body: 23g/m ² quantitative ceramic fiber paper (the mass ratio of flat paper and face paper is 1:1) was respectively applied to the corrugating roll and flat roll of the corrugating machine through the action of sizing agent , hot-rolled (180 ℃) and pasted into single-sided corrugated paper, the composition of the sizing material is 20wt% SiO ₂ sol and 80wt% polyvinyl alcohol glue; then under the action of the above sizing material, it is rolled to form a honeycomb ceramic matrix core; Finally, the surface was cut and polished, and sintered at 500°C for 16 hours to remove organic matter to form a honeycomb ceramic base body (the size of which was φ=4cm(D)×6cm(H)).

(2) Under room temperature and magnetic stirring, take a 500mL beaker, according to the molar ratio of fumaric acid/alkali/water to be 1.0/3.6/80, take 23.2g fumaric acid, 28.8g sodium hydroxide, 288ml deionized water and add In the beaker, after the raw materials are dissolved and stirred evenly, 2.0 g of PVP powder is added, and the stirring is continued to obtain a clear and transparent solution A. The mass of the added PVA powder accounts for 0.59wt% of the mass of the clear and transparent solution A; the honeycomb ceramic embryo is immersed In the clear and transparent solution A, it was taken out after being completely wetted, and then dried at 70° C. for 8 hours to form a honeycomb ceramic body containing sodium fumarate. Take another 500ml beaker, dissolve 75.0g of Al(NO ₃ ) ₃ ·9H ₂ O in 240ml of deionized water, stir until dissolved to form solution B (the mass percentage concentration of solution B is 13.5wt%); The honeycomb ceramic body of sodium was immersed in solution B, placed in a water bath, heated at 70 °C for 40 min, cooled to room temperature, centrifuged to collect the precipitate, washed three times with deionized water, and dried at 150 °C 20 h, and then activated at 350° C. for 7 h to obtain the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent.

Example 7

(1) Preparation of honeycomb ceramic body: 23g/m ² quantitative ceramic fiber paper (the mass ratio of flat paper and face paper is 1:1) was respectively applied to the corrugating roll and flat roll of the corrugating machine through the action of sizing agent , hot-rolled (180°C) and pasted into single-sided corrugated paper, the composition of the sizing material is 45wt% SiO ₂ sol and 55 wt% VAE glue; then under the action of the above sizing material, it is rolled to form a honeycomb ceramic matrix core; The surface was cut and polished, and sintered at 500° C. for 16 h to remove organic matter to form a honeycomb ceramic base body (the size of which was φ=4cm(D)×6cm(H)).

(2) Under room temperature and magnetic stirring, take a 500mL beaker, according to the molar ratio of fumaric acid/alkali/water to be 1.0/3.2/70, take 23.2g fumaric acid, 35.8g potassium hydroxide, 252ml deionized water and add In the beaker, after the raw materials are dissolved and stirred evenly, 1.8g of PVA powder is added, and the stirring is continued to obtain a clear and transparent solution A. The mass of the added PVA powder accounts for 0.58wt% of the mass of the clear and transparent solution A; the honeycomb ceramic embryo is immersed In the clear and transparent solution A, take it out after it is completely wet, and then dry it at 50 ° C for ₁₀ hours to form a honeycomb ceramic embryo body containing potassium fumarate _{; 3.} 18H ₂ O was dissolved in 240 ml of deionized water, stirred until dissolved to form solution B (the mass percentage concentration of solution B was 11.1 wt %); the honeycomb ceramic body containing sodium fumarate was immersed in solution B, Put it in a water bath, heat it in a 60°C water bath for 50min, cool it to room temperature, take the precipitate by centrifugation, wash it three times with deionized water, dry it at 150°C for 24h, and then activate it at 350°C for 12h to obtain the Honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent.

Example 8

(1) Preparation of honeycomb ceramic body: 23g/m ² quantitative ceramic fiber paper (the mass ratio of flat paper and face paper is 1:1) was respectively applied to the corrugating roll and flat roll of the corrugating machine through the action of sizing agent , hot-rolled (180°C) and pasted into single-sided corrugated paper, the composition of the sizing material is 80wt% SiO ₂ sol and 20wt% VAE glue; then under the action of the above sizing material, it is rolled to form a honeycomb ceramic matrix core; The surface was cut and polished, and sintered at 500° C. for 16 h to remove organic matter to form a honeycomb ceramic base body (the size of which was φ=4cm(D)×6cm(H)).

(2) Under room temperature and magnetic stirring, take a 500mL beaker, according to the molar ratio of fumaric acid/alkali/water to be 1.0/3.4/100, take 23.2g fumaric acid, 27.2g sodium hydroxide, 360ml deionized water and add In the beaker, after stirring evenly, add 1.5g of PVP powder, and continue to stir to obtain a clear and transparent solution A. The mass of the added PVA powder accounts for 0.37wt% of the mass of the clear and transparent solution A; the honeycomb ceramic embryo is immersed in the clear and transparent solution A. _In solution _A , take it out after it is completely wet, and then dry it at 80°C for ₅ hours to form a honeycomb ceramic embryo body containing potassium fumarate _; In 240ml of deionized water, stir until dissolved to form solution B (the mass percentage concentration of solution B is 11.1 wt %); immerse the honeycomb ceramic body containing sodium fumarate in solution B, and place it in a water bath temperature It was placed in a 50°C water bath and heated for 60min, cooled to room temperature, centrifuged to collect the precipitate, washed three times with deionized water, dried at 150°C for 20h, and then activated at 350°C for 10h to obtain the honeycomb ceramic-based aluminum-rich Maleic acid MOF adsorbent.

Test conditions and methods

The activation conditions of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example) and powdered aluminum-fumaric acid (Comparative Example) were activated at 350°C for 3 hours, and then tested;

Calculation of the loading of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example):

Assuming that the mass of the honeycomb ceramic base body is m ₁ , and the total mass of the honeycomb ceramic base aluminum-fumaric acid MOF adsorbent obtained by activation after the crystallization reaction is m ₂ , then the load of the honeycomb ceramic base aluminum-fumaric acid MOF adsorbent is The quantity A can be expressed as:

X-ray Diffraction Analysis

The honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example) and powdered aluminum-fumaric acid (Comparative Example) were respectively made into XRD samples, and then the automatic X-ray diffraction of the German Bruker company model D8 Advance was used. The phase analysis was carried out on the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent sample (Example) and the powdered aluminum-fumaric acid sample (Comparative Example) by XRD (XRD); test parameters: the scanning range is 5-50 degrees , the scanning speed is 0.1 sec/step, the scanning step size is 0.02 degrees, and the Cu target is used.

Scanning Electron Microscope (SEM)

The honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example) and powdered aluminum-fumaric acid (Comparative Example) were respectively made into SEM samples; first, the samples were coated with gold targets, and then scanned respectively, wherein Scanning voltage 5kv.

Crystalline adsorption kinetic curve of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example)

The honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example) was placed in a small chamber with constant temperature and humidity (25°C, relative humidity RH60%), and weighed in an electronic balance (Sartorius S220), every The change of sample quality was recorded for a certain period of time (60s), and the data was collected and analyzed.

The weight of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example) is recorded as M ₁ , and then the weight of the adsorbent under constant temperature and humidity conditions is recorded as M ₂ , and the weight when the adsorption is saturated (the mass no longer changes) is M ₃ .

Then the adsorption rate R and the saturated adsorption rate R _s of the adsorbent can be expressed as

R=(M ₂ −M ₁ )/M ₁ (2);

R _s =(M ₃ -M ₁ )/M ₁ (3).

Dynamic isothermal water vapor adsorption curve:

The test uses the AQUADYNE DVS gravity water adsorption analyzer produced by Quantachrome Instruments in the United States to determine the water vapor adsorption isotherm. The instrument is equipped with a precision microbalance with an accuracy of ±0.0001mg, which can directly record the change of the sample quality in the constant temperature control box with the water vapor content, and at the same time accurately control the gas water content to control the relative humidity (RH). The measured humidity range is 0-90%. The honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent sample (Example) and powdered aluminum-fumaric acid MOF sample (Comparative Example) (50.0000 mg each) were activated at 150° C. for 10 hours before the measurements were performed.

Micro-commercial Thermogravimetric Analysis (DTG) Analysis:

The desorption properties of the samples were tested using a TG 209F3 thermogravimetric analyzer (TG) from Netzsch, Germany. The programmed desorption was performed at constant heating rates of 4, 6, 8, 10, and 12 °C·min ^-1 in the range of room temperature to 150 °C, respectively. Before measurement, the samples were heated to 150°C to remove impurities, then cooled to 25°C and saturated with water vapor at 60% relative humidity. The measured sample weight was 15 mg. The derivation of the TG curve can directly read the peak temperature (T _p ) at each heating rate, and the corresponding desorption activation energy (E _d ) can be calculated according to the Kissinger equation.

Among them, Ed is the activation energy of desorption, the unit is kJ·mol ^-1 ; R is the gas constant, 8.314J/(mol·K); T _P is the desorption temperature (K); β is the heating rate (K·min ^{- 1} ).

The XRD spectra of Example 1 and Comparative Example are shown in FIG. 1 . It can be seen from Figure 1 that the XRD peak shape and peak position of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example 1) synthesized in situ are consistent with the powder aluminum-fumaric acid (Comparative Example), which proves that the In situ method can synthesize aluminum-fumaric acid MOF adsorbent on the surface of ceramic fiber. The effects of the adsorbents prepared in other examples are similar to those in Example 1, and they are all aluminum-fumaric acid MOF adsorbents synthesized by the in-situ method, as shown in FIG. 1 .

The scanning electron microscope images of Example 1 and Comparative Example are shown in FIG. 2 . It can be seen from part a (cross-sectional view) of Figure 2 that the coating thickness of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent of Example 1 is about 245 μm, and the substance with adsorption effect is closely combined with the ceramic fiber; from the b of Figure 2 It can be seen in part that in the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent of Example 1, the ceramic fibers and the substance with adsorption effect are closely combined. Continue to enlarge the front view (part b) to obtain part c of Figure 2 , it can be seen that the aluminum-fumaric acid strip crystals grown in situ on the ceramic fibers are interconnected to form a porous three-dimensional network structure. Due to this structure, water vapor is easily adsorbed on the substrate by the Al-Fumaric acid adsorbent, and is adsorbed on the micropores of Al-Fumaric acid under the action of hydrogen bonding, capillary force and chemical bonding of unsaturated metal sites Inside. Part d of Fig. 2 shows the directly synthesized powdered aluminum-fumaric acid (comparative example), and compared with the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent of Example 1, the crystal powders are more closely combined with each other, indicating that Powdered aluminum-fumaric acid (comparative example) has higher resistance to heat and mass transfer. The honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent prepared in other examples is similar in effect to Example 1, and is also a porous three-dimensional network structure, and its ceramic fibers and substances with adsorption effects are also closely combined. figure 2.

The static water adsorption curves of Example 1 and Comparative Example are shown in FIG. 3 . The results show that the saturated adsorption rates of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent of Example 1 and the powdered aluminum-fumaric acid (comparative example) are 27.35% and 34.26%, respectively. Considering the loading of aluminum-fumaric acid in ceramic fibers (75.97%), its theoretical equilibrium adsorption capacity is 36.00%, which is slightly higher than that of powdered aluminum-fumaric acid (comparative example). In addition, compared with powdered aluminum-fumaric acid (comparative example), the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent of Example 1 has a higher early adsorption rate (saturation within 6 minutes), which means that using The honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent of Example 1 synthesized in situ is more suitable for rotary dehumidification. The effects of other examples are similar to those of Example 1, and the prepared honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent is also suitable for rotary dehumidification, as shown in FIG. 3 .

Fig. 4 Dynamic isotherm water adsorption curves of honeycomb ceramic-based aluminum-fumaric acid MOF adsorbents synthesized in Examples 1-5. It can be seen from Figure 4 that the water vapor adsorption isotherms of the adsorbents prepared in Examples 1-5 are all S-shaped. Among them, Example 1 has a higher water vapor equilibrium adsorption capacity (0.3906g/g), and its theoretical equilibrium adsorption capacity reaches 0.5141g/g, which is much higher than that of conventional molecular sieves (below 0.25g/g). The effect of the adsorbents prepared in Example 6, Example 7 and Example 8 is similar to that of Example 1, and the water vapor adsorption isotherm curve is also S-shaped, and also has a higher equilibrium adsorption capacity, as shown in Figure 4.

Table 1 below shows the loading of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent synthesized in Examples 1-5, and the loading is in the range of 64.42% to 75.97%, indicating that the in-situ crystallization process was used to synthesize the honeycomb ceramic substrate. The loading of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent is much higher than that of the molecular sieve in the conventional coating process (below 45%), and the highest loading in Example 1 is 75.97%.

Table 1

Table 2 below is the desorption temperature (T p ) and desorption temperature (T _p ) and desorption of aluminum-fumaric acid powder (comparative example) and in-situ synthesized honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example 1) at different heating rates Attached activation energy (E _d ). By comparison, at the same heating rate, the desorption temperature of the honeycomb ceramic-based aluminum-fumarate MOF adsorbent (Example 1) is much lower than that of powder aluminum fumarate (Comparative Example). And it is calculated that the desorption activation energy of the honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent (Example 1, 55.8 kJmol ^-1 ) is lower than that of powdered aluminum-fumaric acid (Comparative example, 66.1 kJmol ^-1 ). It shows that the former has a lower desorption temperature. The desorption effect of other examples is similar to that of Example 1, and also has a lower desorption temperature, please refer to Table 2.

Table 2

The above examples are only preferred embodiments of the present invention, and are only used to explain the present invention, but not to limit the present invention. Changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention shall belong to the present invention. the scope of protection of the invention.

Claims (7)

1. an in-situ synthesis method of honeycomb ceramic base aluminum-fumaric acid MOF adsorbent, is characterized in that, comprises the steps: (1) fumaric acid, alkaline substance and water are mixed, stir, then add The thickening agent is mixed evenly to obtain a mixed solution, the honeycomb ceramic base embryo body is immersed in the mixed solution, taken out and dried to obtain the embryo body containing deprotonated fumaric acid; The embryo body containing the deprotonated fumaric acid is immersed in an aluminum salt solution, heated in a water bath, cooled to room temperature, filtered to remove the precipitate, washed, dried, and heated for sintering activation treatment to obtain the honeycomb ceramic-based aluminum-rich Maleic acid MOF adsorbent; the thickening agent in step (1) is one or more of polyvinyl alcohol, polyvinylpyrrolidone and sodium carboxymethyl cellulose; the quality of the thickening agent accounts for 30% of the quality of the mixed solution 0.1wt%-1wt%; The drying temperature of step (1) is 30-100°C, and the drying time is 3-12h; In step (2), the temperature of the water bath heating treatment is 30°C-80°C, and the water bath heating treatment time is 20-120 min. 2. in-situ synthesis method according to claim 1, is characterized in that, the alkaline substance described in step (1) is inorganic alkaline substance or organic alkaline substance; Described alkaline substance is sodium hydroxide, hydroxide More than one of potassium, ammonia, methylamine, ethylamine, propylamine, butylamine, diethylamine, dipropylamine and dibutylamine; the mol ratio of the basic substance and fumaric acid is 2.5-4.0:1; The molar ratio of water and fumaric acid is 4-120:1. 3. The in-situ synthesis method according to claim 1, wherein the preparation of the honeycomb ceramic matrix body in step (1) comprises: hot-rolling the fiber paper under the action of a sizing material and pasting it into a single sheet The surface corrugated paper is then rolled into a honeycomb ceramic matrix core body, which is heated and sintered to obtain the honeycomb ceramic matrix body. 4. The in-situ synthesis method according to claim 3, wherein the fiber paper is one of ceramic fiber paper and glass fiber paper; the sizing material is silica sol, aluminum sol, titanium sol, zirconium One or more of sol, polyvinyl acetate, polyvinyl alcohol glue, acrylate and organosilicon modified acrylate; the temperature of the sintering treatment is 350-700 DEG C, and the sintering treatment time is 10-24h. 5. in-situ synthesis method according to claim 1, is characterized in that, the described aluminium salt solution of step (2) is the mixture that aluminium salt and water are mixed; Described aluminium salt is aluminium sulfate, aluminium nitrate, chloride One or more of aluminum and aluminum potassium sulfate; the mass percentage concentration of the aluminum salt solution is 5wt%-20wt%. 6 . The in-situ synthesis method according to claim 1 , wherein the temperature of the sintering activation treatment in step (2) is 345-355° C., and the time of the sintering activation treatment is 6-12 h. 7 . 7. A honeycomb ceramic-based aluminum-fumaric acid MOF adsorbent prepared by the preparation method of any one of claims 1-6.

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