Process for the preparation of porous polymeric adsorbents for the purification of nitric oxide

Abstract

The application discloses a preparation method of a porous polymer adsorbent for nitric oxide purification, which comprises the following steps: mixing a template monomer and a first initiator to obtain a first solution, dropping the first solution into deionized water containing an emulsifier to obtain a first emulsion, and heating the first emulsion in a water bath to perform emulsion polymerization reaction and obtain a template emulsion; mixing wall material monomers and the template emulsion to obtain a second solution, adding a second initiator, heating the emulsion in a water bath to perform emulsion polymerization reaction, and obtaining a microsphere emulsion; adjusting the pH of the microsphere emulsion to be between 8 and 12, heating the emulsion in a water bath to perform hydrolysis reaction, and obtaining a second emulsion; mixing a third solution obtained by mixing a crosslinking monomer and a third initiator into the second emulsion, and heating the emulsion in a water bath to perform monomer polymerization reaction and obtain a third emulsion; and performing suction filtration on the third emulsion, and performing vacuum drying to obtain a granular porous polymer adsorbent. The preparation method has low cost and simple process, and the prepared adsorbent has high adsorption rate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of adsorbents, and particularly relates to a preparation method of a porous polymer adsorbent for purification of nitric oxide. BACKGROUND

[0002] Nitric oxide plays an important role in the medical field and the field of electronic component manufacturing. In the medical field, inhaled nitric oxide can be used to selectively reduce pulmonary arterial hypertension and treat diseases such as pulmonary arterial hypertension, high-altitude pulmonary edema, seawater respiratory distress syndrome, and neonatal respiratory distress syndrome. In the field of electronic component manufacturing, high-purity nitric oxide, as an electronic gas, can be used in the dielectric film process and gate oxide nitriding process of semiconductor optoelectronic devices.

[0003] A relatively common method for producing nitric oxide is to react sodium nitrite with dilute sulfuric acid to obtain nitric oxide. However, in the production process, air infiltration and impurities dissolved in the raw materials often produce impurities such as CO2, NO2, N2O, N2, SO2, and water vapor. Among them, CO2, NO2, and SO2, which are acidic gases, can be removed by alkali washing, N2 and O2, which are non-reactive products, can be treated by pretreating the reaction device and raw materials to prevent air from entering. Water vapor and N2O can be removed by distillation, but the cost of distillation equipment is high. In addition, liquid NO is an extremely sensitive and explosive substance, and the use of distillation for impurity removal is not conducive to large-scale safe production. Another purification technology for nitric oxide is to use various adsorbents for adsorption. Existing adsorbents can cause nitric oxide to undergo disproportionation or oxidation, or the adsorbents themselves have large pore sizes and limited adsorption capacity. Moreover, such adsorbents are dependent on imports and have high costs.

[0004] The information disclosed in this Background section is only for the purpose of increasing the understanding of the background of the present application and should not be taken as an acknowledgment or any form of suggestion that this information forms prior art that is already known to a person of ordinary skill in the art. SUMMARY

[0005] The present application aims to provide a preparation method of a porous polymer adsorbent for purification of nitric oxide, which has low cost, high adsorption rate, and can be used for industrial production. In addition, the porous polymer adsorbent of the present application can adsorb and separate NO2 and moisture, and can effectively inhibit the disproportionation of NO into NO2 and N2O.

[0006] To achieve the above-mentioned purpose, the technical solution provided by an embodiment of the present application is as follows: a preparation method of a porous polymer adsorbent for purification of nitric oxide, comprising:

[0007] Preparation of microsphere template: a first solution is obtained by mixing template monomers and a first initiator, the first solution is added dropwise into deionized water containing an emulsifier to emulsify, a first emulsion is obtained, and the first emulsion is heated in a water bath to perform emulsion polymerization to obtain a template emulsion; wherein the template monomers are selected from one or more of acrylic monomers, acrylate monomers and acrylic anhydride monomers;

[0008] Preparation of mesoporous microspheres: a second solution is obtained by mixing wall material monomers and the template emulsion, and a second initiator is added, and the emulsion is heated in a water bath to perform emulsion polymerization to obtain a microsphere emulsion; the pH of the microsphere emulsion is adjusted to be between 8 and 12, and the hydrolysis reaction is performed by heating in a water bath to obtain a second emulsion; wherein the wall material monomers are selected from one or more of styrene, acrylic monomers, acrylate monomers and acrylamide monomers;

[0009] Polyacrylamide crosslinking: a third solution is obtained by mixing a crosslinking monomer and a third initiator, the third solution is poured into the second emulsion, and the monomer polymerization is performed by heating in a water bath to obtain a third emulsion; wherein the crosslinking monomers are selected from one or more of acrylamide monomers, acrylic monomers and acrylonitrile monomers;

[0010] Drying: the third emulsion is filtered and vacuum dried to obtain granular porous polymer adsorbent.

[0011] In one or more embodiments of the present application, the template monomers are selected from one or more of hydroxyethyl acrylate, methyl methacrylate, methyl acrylate, 2-benzyl acrylate and acrylic anhydride.

[0012] In one or more embodiments of the present application, the first initiator is selected from one or more of benzoyl peroxide and azobisisobutyronitrile.

[0013] In one or more embodiments of the present application, the emulsifier is selected from one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, polyvinyl pyrrolidone, Span 60 and Tween 80.

[0014] In one or more embodiments of the present application, the wall material monomers are selected from one or more of styrene, hydroxyethyl acrylate, methyl methacrylate, p-methyl cinnamic acid, acrylic anhydride, acrylamide and methyl methacrylamide.

[0015] In one or more embodiments of the present application, the second initiator and the third initiator are selected from one or more of azobisisobutyronitrile hydrochloride, ammonium persulfate and potassium persulfate.

[0016] In one or more embodiments of the present application, the cross-linking monomer is selected from one or more of acrylic acid, acrylonitrile, acrylamide, methacrylamide, N-methylol acrylamide, and N,N'-methylene bisacrylamide.

[0017] In one or more embodiments of the present application, in the step of preparing the microsphere template, the water bath heating temperature is between 50-80℃; and / or, the emulsion polymerization reaction time is between 3-6h.

[0018] In one or more embodiments of the present application, in the step of preparing the mesoporous microspheres, the water bath heating temperature is between 50-80℃; and / or, the emulsion polymerization reaction time is between 4-8h; and / or, the microsphere emulsion hydrolysis reaction time is between 2-6h, and the hydrolysis temperature is between 75-95℃.

[0019] In one or more embodiments of the present application, in the step of cross-linking the polyacrylamide, the water bath heating temperature is between 50-80℃.

[0020] In one or more embodiments of the present application, in the step of drying, the drying temperature is between 60-110℃, and the drying time is between 10-20h.

[0021] Compared with the prior art, the preparation method of the porous polymer adsorbent for purification of nitric oxide has low cost, and the prepared adsorbent has high adsorption efficiency. After modification by acrylic acid, the hollow microspheres are enriched with carboxylic acid groups with high hydrophilicity, have high specific surface area, and provide significant water absorption and water retention capacity. The mesoporous structure on the surface of the microspheres provides an exchange path for guiding the gas to enter and exit the microspheres. The porous network structure of the cross-linked polyacrylamide has good adsorption capacity due to the enrichment of amine groups, and provides support, so that the entire adsorbent has excellent mechanical strength and processability. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 The flow chart of the preparation method of the porous polymer adsorbent for purification of nitric oxide in an embodiment of the present application. DETAILED DESCRIPTION

[0024] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0025] like Figure 1 As shown, a method for preparing a porous polymer adsorbent for nitric oxide purification according to an embodiment of the present invention includes steps S1-S4.

[0026] Step S1, preparing microsphere template: Mix template monomer and first initiator to obtain first solution, add first solution dropwise to deionized water containing emulsifier for emulsification to obtain first emulsion, heat first emulsion in water bath for emulsion polymerization reaction to obtain template emulsion.

[0027] Specifically, in step S1, the template monomer and the first initiator are mixed to obtain a first solution, and the first solution is added dropwise to deionized water containing an emulsifier and emulsified at room temperature for 20-40 minutes to obtain a first emulsion.

[0028] Next, the first emulsion is transferred to a reaction flask and heated in a water bath at 50℃-80℃ for 3-6 hours to carry out emulsion polymerization, obtaining a template emulsion with template microspheres. In this step, if the temperature is too low, free radical polymerization may not be initiated, or the reaction rate may be too fast; if the temperature is too high, explosive polymerization may occur. If the reaction time is too short, the conversion rate of the template monomer is low, resulting in a large amount of residual monomer, and the template monomer cannot be formed; if the reaction time is too long, there are too few residual template monomers, providing fewer sites for subsequent copolymerization of the wall material monomers, thus making it difficult for the template monomer and wall material monomers to combine, resulting in a low encapsulation rate. Preferably, the water bath heating temperature is between 60℃-70℃, and the emulsion polymerization time is between 4-5 hours.

[0029] The amount of deionized water used is preferably 200g-300g. The template monomer can be selected from one or more of acrylic monomers, acrylate monomers, and acrylic anhydride monomers. Further, the template monomer can be selected from one or more of hydroxyethyl acrylate, methyl methacrylate, methyl acrylate, 2-benzylacrylic acid, and acrylic anhydride. Preferably, the template monomer can be a composition of hydroxyethyl acrylate, methyl acrylate, and 2-benzylacrylic acid.

[0030] The template microspheres prepared by the above template monomers have a better binding effect with the wall material monomers, a higher wall material monomer encapsulation rate, and a higher pore density and specific surface area of ​​the hydrolyzed porous polymer adsorbent, resulting in better performance of the finished product.

[0031] The first initiator can be selected from one or more of benzoyl peroxide and azobisisobutyronitrile. Preferably, the first initiator can be azobisisobutyronitrile.

[0032] The emulsifier can be selected from one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, polyvinylpyrrolidone, Span 60 and Tween 80. Preferably, the emulsifier is a compound emulsifier of Span 60 and Tween 80 in a mass ratio of 1:2. The addition of the emulsifier can improve the stability of the emulsion and affect the particle size of the template microspheres. Preferably, the compound emulsifier makes the emulsion more stable and the particle size distribution of the template microspheres more uniform.

[0033] In step S2, the mesoporous microspheres are prepared by mixing the wall material monomer and the template emulsion to obtain a second solution, adding a second initiator, and heating the emulsion polymerization reaction in a water bath to obtain a microsphere emulsion. The pH of the microsphere emulsion is adjusted to between 8 and 12, and the hydrolysis reaction is carried out in a water bath to obtain a second emulsion.

[0034] Specifically, in step S2, the preparation of mesoporous microspheres includes the following steps: mixing the wall material monomer and the template emulsion to obtain a second solution. A second initiator is added to the second solution, and the emulsion polymerization reaction is carried out in a water bath at a temperature of 50-80°C for 4-8 hours to obtain a microsphere emulsion. Sodium hydroxide is added to the microsphere emulsion to adjust the pH of the microsphere emulsion to between 8 and 12. The microsphere emulsion and the template emulsion are heated in a water bath at 75-95°C for 2-6 hours to obtain a second emulsion. Specifically, the template microspheres and part of the wall material monomer undergo hydrolysis reaction, and the template monomer swells to form mesoporous hollow structure microspheres. In a weak alkaline environment, ester groups hydrolyze and carboxyl groups are neutralized. The speed of water absorption and swelling of the template microspheres is related to the hydrolysis speed. Controlling the pH controls the hydrolysis speed, so that the template microspheres swell at an appropriate speed. Preferably, the emulsion polymerization time is between 5 and 7 hours. The hydrolysis reaction time of the microsphere emulsion is between 2 and 4 hours. The temperature is between 80 and 90°C.

[0035] In step S2, the wall material monomer can be selected from one or more of styrene, acrylic monomer, acrylate monomer and acrylamide monomer. Further, the wall material monomer can be selected from one or more of styrene, hydroxyethyl acrylate, methyl methacrylate, p-methyl cinnamic acid, acrylic anhydride, acrylamide and methacrylamide. The mechanical properties of the wall material need to be considered during the hydrolysis and swelling process of the wall material monomer, and the wall material needs to have good ductility. The above-mentioned wall material monomers have good affinity with the template monomer, thereby ensuring the mechanical properties of the wall material. Preferably, the wall material monomer can be a combination of styrene, p-methyl cinnamic acid and methacrylamide.

[0036] The second initiator can be selected from one or more of azobisisheptylnitrile hydrochloride, ammonium persulfate and potassium persulfate. Preferably, the second initiator can be azobisisheptylnitrile hydrochloride.

[0037] In step S3, the polyacrylamide is crosslinked by mixing a crosslinking monomer and a third initiator to obtain a third solution, pouring the third solution into the second emulsion, mixing, and heating in a water bath to perform a monomer polymerization reaction to obtain a third emulsion.

[0038] In step S3, the polyacrylamide is crosslinked by mixing a crosslinking monomer and a third initiator to obtain a third solution, pouring the third solution into the second emulsion, mixing, and heating in a water bath to perform a monomer polymerization reaction to obtain a third emulsion.

[0039] The crosslinking monomer can be selected from one or more of an acrylamide monomer, an acrylic acid monomer and an acrylonitrile monomer. Specifically, the crosslinking monomer can be selected from one or more of acrylic acid, acrylonitrile, acrylamide, methacrylamide, N-hydroxymethyl acrylamide and N,N'-methylene bisacrylamide. Preferably, the crosslinking monomer can be a combination of acrylic acid, acrylonitrile, methacrylamide and N,N'-methylene bisacrylamide.

[0040] The third initiator can be selected from one or more of azobisisheptylnitrile hydrochloride, ammonium persulfate and potassium persulfate. Preferably, the third initiator can be azobisisheptylnitrile hydrochloride.

[0041] In step S4, the third emulsion is suction filtered and vacuum dried to obtain a granular porous polymer adsorbent.

[0042] In step S4, the third emulsion is suction filtered and vacuum dried to obtain a granular porous polymer adsorbent.

[0043] The granular porous polymer adsorbent can also be regenerated by purging the adsorption column with nitrogen at 80-120°C for 10-20h, cooling, vacuumizing, and then purging with helium for 4-10h.

[0044] The application will be further described below with reference to specific examples and comparative examples.

[0045] Example 1

[0046] Preparation of microsphere template: take hydroxyethyl acrylate (16 g), methyl acrylate (30 g), 2-benzyl acrylate (8 g) and azobisisobutyronitrile (0.035 g) to mix to obtain a first solution, drop the first solution into deionized water (250 g) containing Span 60 (1 g) and Tween 80 (2 g) to emulsify at room temperature for 30 min to obtain a first emulsion. The first emulsion is transferred into a reaction bottle, heated in a 65°C water bath to carry out emulsion polymerization for 5 h to obtain a template emulsion.

[0047] Preparation of mesoporous microspheres: take styrene (70 g), hydroxyethyl acrylate (10 g), p-methyl cinnamic acid (15 g), and methyl methacrylamide (15 g) to mix to obtain a second solution, slowly drop the second solution into the template emulsion, add azobisisobutyronitrile hydrochloride, heat in a 65°C water bath to carry out emulsion polymerization for 6 h to obtain a microsphere emulsion, add sodium hydroxide to adjust the pH of the microsphere emulsion to 10, adjust the water bath temperature to 90°C to carry out hydrolysis reaction for 3 h to obtain a second emulsion.

[0048] Polyacrylamide crosslinking: mix acrylic acid (30 g), acrylonitrile (15 g), methyl methacrylamide (40 g), N,N'-methylene bisacrylamide (15 g) and azobisisobutyronitrile hydrochloride (0.2 g) to obtain a third solution, pour the third solution into the second emulsion. Heat in a 60°C water bath to initiate monomer polymerization to form a crosslinked structure to obtain a third emulsion.

[0049] Drying: after suction filtration of the third emulsion, vacuum drying at 100°C for 15 h to obtain a granular porous polymer adsorbent.

[0050] Example 2

[0051] Preparation of microsphere template: take methyl methacrylate (45 g), acrylic anhydride (10 g) and azobisisobutyronitrile (0.05 g) to mix to obtain a first solution, drop the first solution into deionized water (250 g) containing Span 60 (0.1 g) and Tween 80 (0.2 g) to emulsify at room temperature for 30 min to obtain a first emulsion. The first emulsion is transferred into a reaction bottle, heated in a 65°C water bath to carry out emulsion polymerization for 5 h to obtain a template emulsion.

[0052] Preparation of mesoporous microspheres: take styrene (70 g), methyl methacrylate (10 g), acrylic anhydride (10 g) and acrylamide (15 g) to mix to obtain a second solution, slowly drop the second solution into the template emulsion, add azobisisobutyronitrile hydrochloride, heat in a 65°C water bath to carry out emulsion polymerization for 6 h to obtain a microsphere emulsion, add sodium hydroxide to adjust the pH of the microsphere emulsion to 11, adjust the water bath temperature to 90°C to carry out hydrolysis reaction for 3 h to obtain a second emulsion.

[0053] Polyacrylamide crosslinking: Acrylic acid (30g), acrylamide (60g), N-hydroxymethylacrylamide (15g), and azobisisobutyronitrile hydrochloride (0.2g) are mixed to obtain a third solution. The third solution is poured into the second emulsion, and the monomer polymerization reaction is initiated by heating in a water bath at 60°C to form a crosslinked structure to obtain the third emulsion.

[0054] Drying: After filtering the third emulsion, vacuum drying was carried out at 100℃ for 10h to obtain a particulate porous polymer adsorbent.

[0055] Example 3

[0056] Preparation of microsphere template: Hydroxyethyl acrylate (16g), methyl acrylate (30g), and benzamide peroxide (0.04g) were weighed and mixed to obtain a first solution. This first solution was then added dropwise to 250g of deionized water containing 3g of sodium dodecylbenzenesulfonate, and emulsified at room temperature for 30 minutes to obtain a first emulsion. The first emulsion was transferred to a reaction flask and heated in a 65°C water bath for emulsion polymerization reaction for 5 hours to obtain the template emulsion.

[0057] Preparation of mesoporous microspheres: Weigh styrene (70g), methyl methacrylate (10g), and methacrylamide (20g) and mix them to obtain a second solution. Slowly add the second solution dropwise to the template emulsion. Add ammonium persulfate and heat the emulsion in a water bath at 65°C for 6 hours to obtain a microsphere emulsion. Add sodium hydroxide to adjust the pH of the microsphere emulsion to 10-11 and adjust the water bath temperature to 90°C to carry out a hydrolysis reaction for 3 hours to obtain a second emulsion.

[0058] Polyacrylamide crosslinking: Acrylic acid (30g), acrylonitrile (15g), methacrylamide (40g), N,N'-methylenebisacrylamide (15g), and ammonium persulfate (0.3g) are mixed to obtain a third solution. The third solution is poured into the second emulsion, and the mixture is heated in an 80°C water bath to initiate a monomer polymerization reaction to form a crosslinked structure, thus obtaining the third emulsion.

[0059] Drying: After filtering the third emulsion, vacuum dry it at 100°C for 10 hours to obtain a granular porous polymer adsorbent.

[0060] Example 4

[0061] Preparation of microsphere template: Methyl methacrylate (25g), methyl acrylate (25g), and azobisisobutyronitrile (0.03g) were weighed and mixed to obtain a first solution. This first solution was then added dropwise to 250g of deionized water containing Span 60 (1g) and Tween 80 (2g), and emulsified at room temperature for 30 minutes to obtain a first emulsion. The first emulsion was transferred to a reaction flask and heated in a 65°C water bath for emulsion polymerization reaction for 5 hours to obtain the template emulsion.

[0062] Preparation of mesoporous microspheres: take styrene (70 g), methyl methacrylate (10 g), and mix to obtain a second solution, slowly drop the second solution into the template emulsion, add ammonium persulfate, heat the emulsion polymerization reaction in a water bath at 65°C for 6h to obtain a microsphere emulsion, add sodium hydroxide to adjust the pH of the microsphere emulsion to 9, adjust the water bath temperature to 90°C for hydrolysis reaction for 3h to obtain a second emulsion.

[0063] Polyacrylamide crosslinking: mix acrylic acid (30 g), acrylamide (60 g), N-hydroxymethyl acrylamide (15 g), and azobisisheptane nitrile hydrochloride (0.2 g) to obtain a third solution, pour the third solution into the second emulsion, heat to initiate monomer polymerization reaction to form a crosslinked structure at 60°C water bath to obtain a third emulsion.

[0064] Drying: after suction filtration of the third emulsion, vacuum drying at 100°C for 15h to obtain a granular porous polymer adsorbent.

[0065] Example 5

[0066] Preparation of microsphere template: take hydroxyethyl acrylate (16 g), methyl acrylate (30 g), and azobisisobutyronitrile (0.035 g) to obtain a first solution, drop the first solution into deionized water (250 g) containing Span 60 (1 g) and Tween 80 (2 g) to emulsify at room temperature for 30 min to obtain a first emulsion. Transfer the first emulsion into a reaction bottle, heat in a water bath at 60°C for emulsion polymerization reaction for 4h to obtain a template emulsion.

[0067] Preparation of mesoporous microspheres: take styrene (70 g), p-methyl cinnamic acid (15 g), and methyl methacrylamide (15 g) to obtain a second solution, slowly drop the second solution into the template emulsion, add ammonium persulfate, heat the emulsion polymerization reaction in a water bath at 50°C for 4h to obtain a microsphere emulsion, add sodium hydroxide to adjust the pH of the microsphere emulsion to 11, adjust the water bath temperature to 80°C for hydrolysis reaction for 2h to obtain a second emulsion.

[0068] Polyacrylamide crosslinking: mix acrylic acid (30 g), acrylonitrile (15 g), methyl methacrylamide (40 g), N,N'-methylene bisacrylamide (15 g), and azobisisheptane nitrile hydrochloride (0.2 g) to obtain a third solution, pour the third solution into the second emulsion, heat to initiate monomer polymerization reaction to form a crosslinked structure at 50°C water bath to obtain a third emulsion.

[0069] Drying: after suction filtration of the third emulsion, vacuum drying at 100°C for 10h to obtain a granular porous polymer adsorbent.

[0070] Example 6

[0071] Preparation of microsphere template: Hydroxyethyl acrylate (16g), methyl acrylate (30g), 2-benzylacrylic acid (8g), and azobisisobutyronitrile (0.035g) were weighed and mixed to obtain a first solution. This first solution was then added dropwise to 250g of deionized water containing Span 60 (1g) and Tween 80 (2g), and emulsified at room temperature for 30 min to obtain a first emulsion. The first emulsion was transferred to a reaction flask and heated in a 70℃ water bath for 6 h to obtain the template emulsion.

[0072] Preparation of mesoporous microspheres: Weigh styrene (70g), p-methylcinnamic acid (15g), and methacrylamide (15g) and mix them to obtain a second solution. Slowly add the second solution dropwise to the template emulsion. Heat the emulsion with potassium persulfate in a water bath at 75°C for 6 hours to obtain a microsphere emulsion. Add sodium hydroxide to adjust the pH of the microsphere emulsion to 10, and adjust the water bath temperature to 90°C to carry out a hydrolysis reaction for 4 hours to obtain a second emulsion.

[0073] Polyacrylamide crosslinking: Acrylic acid (30g), acrylonitrile (15g), methacrylamide (40g), N,N'-methylenebisacrylamide (15g), and azobisisoheptanenitrile hydrochloride (0.2g) are mixed to obtain a third solution. The third solution is poured into the second emulsion, and the mixture is heated in a water bath at 50°C to initiate a monomer polymerization reaction to form a crosslinked structure and obtain the third emulsion.

[0074] Drying: After filtering the third emulsion, vacuum dry it at 100℃ for 15h to obtain a particulate porous polymer adsorbent.

[0075] Comparative Example 1

[0076] A commercially available 4A molecular sieve (purchased from Shanghai Jiuzhou Chemical Co., Ltd.) was used as the adsorbent for comparison. The adsorption test method is the same as below.

[0077] Comparative Example 2

[0078] A commercially available 5A molecular sieve (purchased from Shanghai Jiuzhou Chemical Co., Ltd.) was used as the adsorbent for comparison. The adsorption test method is the same as below.

[0079] Comparative Example 3

[0080] ZSM-5 molecular sieve (purchased from Shanghai Jiuzhou Chemical Co., Ltd.) was used as an adsorbent for comparison. The adsorption test method is the same as below.

[0081] The adsorbents of Examples 1-6 and Comparative Examples 1-3 were subjected to adsorption test. The adsorption test was as follows: the adsorbents of Examples 1-6 and Comparative Examples 1-3 were filled into an adsorption column with an inner diameter of 2 cm, the filling length was 10-20 cm, a crude NO gas was passed through the adsorption column at a speed of 0.5-2.0 L / min, and the purity of NO and the impurity contents of N2O, NO2 and H2O were detected by connecting a gas chromatograph and an infrared detector.

[0082] The composition of the crude NO gas was as follows: H2O (8850 ppm), N2O (57.5 ppm), NO2 (268.5 ppm), other impurity gases (302.6 ppm), and NO (99.07%). The total amount of the treated crude NO was 200 L.

[0083] The specific test results are shown in Table 1 below.

[0084] Table 1: Adsorption results of the adsorbents of Examples 1-6 and Comparative Examples 1-3

[0085]

[0086]

[0087] As shown in Table 1 above, compared with the adsorbents of Comparative Examples 1-3, the water removal performance of the porous polymer adsorbents of Examples 1-6 was equivalent to that of the commonly used 4A, 5A and ZSM-5 molecular sieves on the market, but the adsorbents of Examples 1-6 could effectively inhibit the disproportionation reaction of NO. With the increase of the amount of molecular sieves, the water removal performance of Examples 1-6 was further improved, and there was no significant increase in the content of N2O, which indicated that the adsorbents of the present application could effectively inhibit the disproportionation reaction of NO, in addition, the content of NO2 was further reduced, which indicated that the adsorbents of the present application also had good adsorption effect on NO2. However, in Comparative Examples 1-3, with the increase of the amount of molecular sieves, the content of N2O and NO2 increased significantly, although the content of water was effectively reduced, which indicated that the use of these adsorbents would promote the disproportionation reaction of NO, which was not conducive to the purification process of NO.

[0088] In summary, the preparation method of the porous polymer adsorbent for nitric oxide purification has the advantages of low cost, high adsorption rate, and simple regeneration method. In addition, the adsorbent of the present application can adsorb and separate NO2 and moisture, while effectively inhibiting the disproportionation of NO into NO2 and N2O. The adsorbent prepared by the method has hollow voids provided by the modified styrene hollow microspheres; the surface of the modified styrene hollow microspheres has a mesoporous structure. The microspheres are connected by a porous network structure of cross-linked polyacrylamide. After modification by acrylic acid, the styrene hollow microspheres are enriched with carboxylic acid groups with high hydrophilicity, have a high specific surface area, and provide excellent water absorption and water retention capacity. The mesoporous structure of the microsphere surface provides an exchange path for guiding the entry and exit of gas into and out of the microspheres. The porous network structure of cross-linked polyacrylamide has good adsorption capacity due to the enrichment of amine groups, and also provides support, so that the adsorbent has excellent mechanical strength and processability.

[0089] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments, but that the application can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than by the above description, and it is therefore intended that all changes and modifications that fall within the meaning and range of equivalency of the elements of the claims are encompassed by the application. Any reference signs in the claims should not be construed as limiting the claims to the figures in which the reference signs are used.

[0090] Furthermore, it should be understood that, although the present specification is described in terms of embodiments, not every implementation can contain all of the features that are described in those embodiments, and not every implementation can be identical to the implementations described in the specification. The specification is therefore to be considered in its entirety as a written description intent to cover all alternatives consistent with the principles of the application. Any reference signs in the claims should not be construed as limiting the claims to the figures in which the reference signs are used.

Claims

1. A method for preparing a porous polymer adsorbent for nitric oxide purification, characterized in that, include: Preparation of microsphere template: The template monomer and the first initiator are mixed to obtain a first solution. The first solution is added dropwise to deionized water containing an emulsifier for emulsification to obtain a first emulsion. The first emulsion is heated in a water bath to carry out an emulsion polymerization reaction to obtain a template emulsion. The template monomer is selected from one or more of acrylic monomers, acrylate monomers and acrylic anhydride monomers. Preparation of mesoporous microspheres: A second solution is obtained by mixing a wall material monomer with a template emulsion, and a second initiator is added and heated in a water bath to carry out an emulsion polymerization reaction to obtain a microsphere emulsion; the pH of the microsphere emulsion is adjusted to between 8 and 12, and a hydrolysis reaction is carried out in a water bath to obtain a second emulsion; the template microspheres and part of the wall material monomer undergo a hydrolysis reaction, and the template monomer expands to form mesoporous hollow microspheres, wherein the wall material monomer is selected from one or more of styrene, acrylic monomers, acrylate monomers, and acrylamide monomers; Polyacrylamide crosslinking: A third solution is obtained by mixing a crosslinking monomer and a third initiator, and the third solution is poured into the second emulsion and mixed. The monomer polymerization reaction is carried out by heating in a water bath to obtain the third emulsion; wherein, the crosslinking monomer is selected from one or more of acrylamide monomers, acrylic monomers and acrylonitrile monomers; Drying: The third emulsion is filtered and vacuum dried to obtain a granular porous polymer adsorbent. The porous polymer adsorbent is enriched with highly hydrophilic carboxylic acid groups in the hollow mesoporous microspheres modified with acrylic acid, which has a high specific surface area and provides significant water absorption and retention capacity. The mesoporous structure on the surface of the mesoporous microspheres provides an exchange path for guiding gas into and out of the mesoporous microspheres. The cross-linked polyacrylamide porous network structure is enriched with amine groups and has good adsorption capacity, and provides a supporting effect, giving the porous polymer adsorbent excellent mechanical strength and processability.

2. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, The template monomer is selected from one or more of hydroxyethyl acrylate, methyl methacrylate, methyl acrylate, 2-benzylacrylic acid, and acrylic anhydride.

3. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, The first initiator is selected from one or more of benzamide peroxide and azobisisobutyronitrile.

4. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, The emulsifier is selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, polyvinylpyrrolidone, Span 60, and Tween 80.

5. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, The wall material monomers are selected from one or more of styrene, hydroxyethyl acrylate, methyl methacrylate, p-methylcinnamic acid, acrylamide, and methacrylamide.

6. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, The second initiator and the third initiator are selected from one or more of azobisisobutyronitrile hydrochloride, ammonium persulfate and potassium persulfate.

7. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, The crosslinking monomer is selected from one or more of acrylic acid, acrylonitrile, acrylamide, methacrylamide, N-hydroxymethylacrylamide, and N,N'-methylenebisacrylamide.

8. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, In the step of preparing the microsphere template, the water bath heating temperature is between 50°C and 80°C; and / or, the emulsion polymerization and reaction time is between 3h and 6h.

9. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, In the step of preparing mesoporous microspheres, the water bath heating temperature is between 50℃ and 80℃; and / or, the emulsion polymerization reaction time is between 4h and 8h; and / or, the microsphere emulsion hydrolysis reaction time is between 2h and 6h, and the hydrolysis temperature is between 75℃ and 95℃.

10. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, In the polyacrylamide crosslinking step, the water bath heating temperature is between 50℃ and 80℃.

11. The method for preparing the porous polymer adsorbent for nitric oxide purification according to claim 1, characterized in that, In the drying step, the drying temperature is between 60℃ and 110℃, and the drying time is between 10h and 20h.

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