Deodorant for purifying paint waste gas and preparation method thereof
By modifying earthworm castings with a mixed aqueous solution of zinc chloride, phosphoric acid, and boric acid, as well as a composite activator of chitosan hydrochloride and hexadecyltrimethylammonium bromide, an optimized pore structure and active sites are formed, solving the problem of insufficient toluene purification performance of earthworm castings adsorbents and achieving a highly efficient toluene purification effect.
Patent Information
- Application Number
- CN202511161474.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-19
- Publication Date
- 2025-10-17
AI Technical Summary
Existing earthworm castings adsorbents have insufficient purification performance for toluene in paint exhaust gas, and further optimization and modification methods are needed to improve their adsorption capacity.
A mixed aqueous solution of zinc chloride, phosphoric acid, and boric acid was used as an activator, combined with a composite activator of chitosan hydrochloride and hexadecyltrimethylammonium bromide. Through specific modification steps, the pore structure and active sites of earthworm castings were improved, forming an amorphous borate network and hierarchical pore structure, thereby enhancing the adsorption capacity of toluene.
It significantly improves the toluene purification performance of earthworm castings adsorbent, with a toluene purification efficiency of over 91.0%, which is superior to traditional methods.
Smart Images
Figure CN120790125A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of waste gas purification, and particularly relates to a deodorizing agent for purifying paint waste gas and a preparation method thereof. BACKGROUND
[0002] Paint, also known as coating, is a liquid or paste material that can firmly adhere to the surface of an object and form a continuous film. Its core function is to protect, decorate or achieve other special functions of the substrate through the formed coating. Modern paint has developed into a complex chemical composition system, becoming an important branch of fine chemical industry. Paint waste gas refers to volatile gaseous pollutants generated during paint construction, drying and curing, and widely exists in manufacturing industries (such as automobile manufacturing, furniture production), building decoration, metal processing and other industries. VOCs, as the core component of paint waste gas, typical substances include benzene series toluene and xylene, alcohol ethanol and butanol, esters and ketones, and typical characteristics are easy to volatilize, toxic and harmful.
[0003] Some VOCs (such as benzene series) have acute toxicity, which can cause headache, nausea and even coma; long-term exposure may cause cancer. In order to reduce the harm, it is necessary and effective to use the corresponding adsorbent (also called deodorizing agent). Conventional adsorbent / deodorizing agent materials include inorganic adsorbents such as activated carbon, zeolite molecular sieve, silica gel and metal organic framework material, and there are also high polymer adsorption resin organic adsorbents with application potential. Due to the differences in morphology, adsorption selectivity and composition between adsorbents, the selection of adsorbent is particularly important in the purification and separation of VOCs (such as toluene).
[0004] Earthworm manure as a selectable adsorbent material is not only cheap and easy to obtain, but also contains a large amount of elemental carbon, organic matter and part of aluminosilicate substances. Research has found that the preparation of earthworm manure adsorbent / deodorizing agent can be continuously optimized by different modification methods, and how to better optimize the modified earthworm manure to improve the application potential of the prepared earthworm manure adsorbent / deodorizing agent (such as improving its toluene purification performance) is a subject worthy of continuous research. SUMMARY
[0005] In order to solve the problems in the background art, the present application provides a deodorizing agent for purifying paint waste gas and a preparation method thereof, which can effectively improve the toluene purification performance of the prepared deodorizing agent.
[0006] In order to achieve the above-mentioned purpose, the present application provides a preparation method of a deodorizing agent for purifying paint waste gas, comprising the following steps: S1, dry earthworm manure and activator are uniformly mixed at a mass ratio of 2:1, soaked at 80℃ for 24h, filtered and dried to constant weight, then placed in an activation furnace, heated to 620±2℃, and activated for 2h to obtain activated earthworm manure; S2, the activated earthworm manure obtained in S1 is soaked in dilute hydrochloric acid for 30-32 min, filtered, washed in an ultrasonic reactor for 30 min (power is 50 kHz), then washed repeatedly with deionized water until neutral, dried at 105℃ for 12 h again, crushed and passed through a 50 mesh sieve to obtain inorganic modified earthworm manure; S3, 30 g of the inorganic modified earthworm manure obtained in S2 is placed in a conical flask, 290-300 mL of concentrated sulfuric acid is added, stirred on a constant temperature 60℃ magnetic stirrer for 3 h, then filtered, washed with deionized water until neutral, dried for 6 h to obtain a sulfonated product; S4, the sulfonated product obtained in S3 is mixed with 740-760 mL of a composite active agent, the conical flask containing the mixed sample is placed in a constant temperature shaking incubator, stirred at 30℃ and a speed of 180 r / min for 3 h, then filtered, washed with deionized water three times, dried at 105℃ for 12 h, crushed and passed through a 50 mesh sieve to obtain the deodorizing agent for purifying paint waste gas. The activating agent is a mixed aqueous solution of zinc chloride, phosphoric acid and boric acid; the composite active agent is a mixed aqueous solution of chitosan hydrochloride and cetyltrimethylammonium bromide.
[0007] Further, in S1, the dry earthworm manure is obtained by drying the earthworm manure at 100-105℃ for 3-3.5 h after airing to loosen.
[0008] Further, the activating agent is prepared by mixing 2 mol / L zinc chloride solution, 2 mol / L phosphoric acid solution and 2 mol / L boric acid solution in a volume ratio of 1:1.7:(0.3-0.5).
[0009] Further, in S1, the heating rate is 18-20℃ / min.
[0010] Further, in S2, the concentration of dilute hydrochloric acid is 2.8-3.2 mol / L.
[0011] Further, in S3, the mass fraction of concentrated sulfuric acid is 64-67%.
[0012] Further, the composite active agent is prepared by dissolving 28-29.5 g of chitosan hydrochloride and 1.8-2.1 g of cetyltrimethylammonium bromide in water and diluting to 1000 mL.
[0013] In a second aspect, the present application provides a deodorizing agent for purifying paint waste gas, which is prepared by the above method.
[0014] The present application has the following beneficial effects: 1. The activator in the present invention is a mixed aqueous solution of zinc chloride, phosphoric acid, and boric acid. Boric acid, as the third component, can synergistically produce a gradient corrosion effect (phosphoric acid-boric acid synergistic pore formation) with phosphoric acid. Phosphoric acid (a medium-strong acid) first opens the main pores, and then boric acid (a weak acid) modifies the pore wall smoothness. At the same time, boric acid inhibits pore blockage caused by excessive polycondensation of phosphoric acid, maintains the open porosity, increases toluene adsorption capacity, and improves toluene purification performance. Boric acid dehydrates at high temperature to generate B2O3, which reacts with SiO2 / Al2O3 in earthworm castings to generate borosilicates, etc., which locally wrap the active sites, inhibit the high-temperature volatilization of zinc chloride, and effectively avoid the reduction of zinc chloride acting inside the earthworm castings; the amorphous borate network formed can also anchor the carbon skeleton, effectively slowing down the pore collapse caused by deep devolatilization at >600°C; while increasing the activation temperature threshold, it also increases the toluene adsorption capacity and improves the toluene purification performance.
[0015] 2. The composite active agent in the present invention is a mixed aqueous solution of chitosan hydrochloride and cetyltrimethylammonium bromide. The chitosan hydrochloride is distributed on the surface of the aluminosilicate and carbon materials, which easily leads to the filling of micropores, a decrease in specific surface area, and a decrease in average pore size, resulting in a decrease in the physical adsorption capacity for toluene. Chitosan hydrochloride adds -CH2 and -NH hydrophobic groups without destroying the basic structure of the inorganic modified earthworm castings, thereby significantly increasing the active sites participating in the chemical adsorption reaction of toluene (the increase in chemical adsorption capacity is greater than the decrease in physical adsorption capacity).
[0016] The cetyltrimethylammonium bromide micelles, as soft templates, can induce chitosan to form a hierarchical pore structure during the mineralization process, indirectly weakening the decline in physical adsorption capacity; the long-chain alkyl groups of cetyltrimethylammonium bromide can also interact with toluene molecules through van der Waals forces, directly enhancing the adsorption capacity; this balance further improves the toluene adsorption capacity and enhances the toluene purification performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a comparative trend chart of toluene purification efficiency test data of the deodorants prepared in Examples 1 to 3 and Comparative Examples 1 to 5 in the test examples of the present invention. DETAILED DESCRIPTION
[0018] The present application is further described in detail below with reference to the embodiments.
[0019] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available. Example 1
[0020] (1) The activator is a mixed aqueous solution of zinc chloride, phosphoric acid and boric acid, which is prepared by mixing 2 mol / L zinc chloride solution, 2 mol / L phosphoric acid solution and 2 mol / L boric acid solution in a volume ratio of 1:1.7:0.4.
[0021] Specifically, clean and dry measuring cylinders are used to measure 1L of 2 mol / L zinc chloride solution into beaker A, 1.7L of 2 mol / L phosphoric acid solution into beaker B, and 0.4L of 2 mol / L boric acid solution into beaker C. Then the phosphoric acid solution in beaker B is slowly poured into the zinc chloride solution in beaker A while stirring (to prevent violent exothermic reaction). Then the boric acid solution in beaker C is poured into the solution in beaker A while stirring. Finally, the solution is continuously stirred at a stirring speed of 150 r / min for 30 min to ensure complete uniformity.
[0022] (2) The composite activator is a mixed aqueous solution of chitosan hydrochloride and cetyltrimethylammonium bromide, which is prepared as follows: 29 g of chitosan hydrochloride and 2 g of cetyltrimethylammonium bromide (CTAB) are dissolved in water and diluted to 1000 mL.
[0023] Specifically, 29 g of chitosan hydrochloride is weighed using a clean and dry weighing boat and transferred to a 1L beaker. 500 mL of deionized water is added to the beaker, and the beaker is placed in a 60℃ water bath for heat preservation and stirring at a speed of 350 rpm. The stirring is continued for 40 min until complete dissolution. 2 g of cetyltrimethylammonium bromide (CTAB) is accurately weighed and slowly added to the above solution (CTAB is prone to foaming, so it should be poured slowly along the wall of the beaker). The water bath is maintained at 60℃, and the stirring is continued for 30 min. The solution should be uniform and transparent without visible suspended solids. The solution is poured into a 1L brown volumetric flask along the glass rod. The beaker is rinsed a few times, and the washings are also transferred. Deionized water is slowly added to the volumetric flask until the mark (the lowest point of the concave liquid surface is flush with the scale). The ground stopper is tightly closed and inverted for 10 times to obtain the composite activator.
[0024] (3) A method for preparing a deodorant for purifying paint waste gas, comprising the following steps: S1, the earthworm manure is dried at 105℃ for 3.2h to obtain dried earthworm manure. The dried earthworm manure is mixed with the activator at a mass ratio of 2:1, soaked at 80℃ for 24h, filtered and dried to constant weight, and then placed in an activation furnace and heated to 620℃ at a heating rate of 20℃ / min. The temperature is maintained at 620℃ for 2h to obtain activated earthworm manure.
[0025] The moisture content of the earthworm manure is 10.07%, the crude ash content is 51.44%, and the combustible content is 38.49%.
[0026] S2, the activated earthworm manure obtained in S1 was soaked in dilute hydrochloric acid with a concentration of 3.0 mol / L for 30 min, filtered, washed in an ultrasonic reactor for 30 min (power 50 kHz), then washed repeatedly with deionized water until neutral, dried at 105 ℃ for 12 h again, crushed and passed through a 50-mesh sieve to obtain inorganic modified earthworm manure.
[0027] S3, 30 g of the inorganic modified earthworm manure obtained in S2 was placed in a conical flask, 295 mL of concentrated sulfuric acid with a mass fraction of 65% was added, and stirring was performed on a magnetic stirrer at a constant temperature of 60 ℃ for 3 h, then filtered, washed with deionized water until neutral, and dried at 105 ℃ for 6 h to obtain a sulfonated product.
[0028] S4, the sulfonated product obtained in S3 was mixed with 750 mL of a composite active agent, and the conical flask containing the mixed sample was placed in a constant-temperature shaking incubator, stirred at 30 ℃ and a speed of 180 r / min for 3 h, then suction-filtered, washed with deionized water three times, and dried at 105 ℃ for 12 h to obtain a deodorant for purifying paint waste gas. Example 2
[0029] The difference between this example and Example 1 is that: (1) the activating agent is a mixed aqueous solution of zinc chloride, phosphoric acid and boric acid, which is prepared by mixing 2 mol / L zinc chloride solution, 2 mol / L phosphoric acid solution and 2 mol / L boric acid solution according to a volume ratio of 1:1.7:0.3.
[0030] (2) the composite active agent is a mixed aqueous solution of chitosan hydrochloride and cetyltrimethylammonium bromide, which is prepared as follows: 28 g of chitosan hydrochloride and 1.8 g of cetyltrimethylammonium bromide are dissolved in water and diluted to 1000 mL. Example 3
[0031] The difference between this example and Example 1 is that: (1) the activating agent is a mixed aqueous solution of zinc chloride, phosphoric acid and boric acid, which is prepared by mixing 2 mol / L zinc chloride solution, 2 mol / L phosphoric acid solution and 2 mol / L boric acid solution according to a volume ratio of 1:1.7:0.5.
[0032] (2) the composite active agent is a mixed aqueous solution of chitosan hydrochloride and cetyltrimethylammonium bromide, which is prepared as follows: 29.5 g of chitosan hydrochloride and 2.1 g of cetyltrimethylammonium bromide are dissolved in water and diluted to 1000 mL.
[0033] Comparative Example 1 The difference between the present comparative example and Example 1 is that, in the preparation of the activator, boric acid is replaced by phosphoric acid; in the preparation of the composite active agent, no cetyltrimethylammonium bromide is added; and in the preparation of the odor removal agent for purifying paint waste gas, the activation temperature is 600℃.
[0034] Specifically, (I) the activator is prepared by mixing 2 mol / L zinc chloride solution and 2 mol / L phosphoric acid solution in a volume ratio of 1:2.1.
[0035] (II) The preparation method of the composite active agent is as follows: 29 g of chitosan hydrochloride is dissolved in water and diluted to 1000 mL, and the composite active agent is obtained.
[0036] (III) A preparation method of an odor removal agent for purifying paint waste gas comprises the following steps: S1, after the earthworm manure is dried at 105℃ for 3.2h, the dried earthworm manure is obtained. The dried earthworm manure and the activator are mixed in a mass ratio of 2:1, and then soaked at 80℃ for 24h. After filtration and drying to constant weight, the mixture is placed in an activation furnace and heated to 600℃ at a heating rate of 20℃ / min. The mixture is activated at 600℃ for 2h to obtain activated earthworm manure.
[0037] S2, the activated earthworm manure obtained in S1 is soaked in 3.0 mol / L dilute hydrochloric acid for 30 min, filtered, washed in an ultrasonic reactor for 30 min (power 50 kHz), then washed repeatedly with deionized water until neutral, and dried at 105℃ for 12h. The inorganic modified earthworm manure is obtained by crushing and passing through a 50 mesh sieve.
[0038] S3, 30g of the inorganic modified earthworm manure obtained in S2 is placed in a conical flask, 295mL of 65% concentrated sulfuric acid is added, and the mixture is stirred on a constant temperature magnetic stirrer at 60℃ for 3h. After filtration, the mixture is washed with deionized water until neutral, and dried at 105℃ for 6h to obtain the sulfonated product.
[0039] S4, the sulfonated product obtained in S3 is mixed with 750mL of the composite active agent. The conical flask containing the mixed sample is placed in a constant temperature shaking incubator and stirred at 30℃ at a speed of 180r / min for 3h. After suction filtration, the mixture is washed with deionized water three times, dried at 105℃ for 12h, crushed and passed through a 50 mesh sieve to obtain the odor removal agent for purifying paint waste gas.
[0040] Comparative Example 2 The difference between the present comparative example and Example 1 is that, in the preparation of the activator, boric acid is replaced by phosphoric acid; in the preparation of the composite active agent, no cetyltrimethylammonium bromide is added.
[0041] Comparative Example 3 The difference between the present comparative example and Example 1 is that no cetyltrimethylammonium bromide is added in the preparation of the composite active agent; and the activation temperature is 600℃ in the preparation of the deodorant for purifying paint waste gas.
[0042] Comparative Example 4 The difference between the present comparative example and Example 1 is that no cetyltrimethylammonium bromide is added in the preparation of the composite active agent.
[0043] Comparative Example 5 The difference between the present comparative example and Example 1 is that the activation temperature is 600℃ in the preparation of the deodorant for purifying paint waste gas.
[0044] Test Example Test object: the deodorants prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 5. Test item and basis: toluene purification performance-toluene purification efficiency (%): detected according to JCT1074-2008 Indoor air purification functional coating materials purification performance. Test result: see Table 1.
[0045] Table 1. Test data of test example
[0046] Result analysis: analysis of Example 1-Example 3 and combination of Table 1 data and Figure 1 It can be seen that the toluene purification efficiency of the deodorant prepared by the present application (Example 1-Example 3) is as high as 91.0% or more; which shows that the toluene purification performance of the deodorant prepared by the present application is excellent.
[0047] Analysis of Example 1 and Comparative Example 1-Comparative Example 5 and combination of Table 1 data and Figure 1 Specifically, by comparing Comparative Example 1 and Comparative Example 2, it can be seen that, compared with the activation temperature of 600℃ of Comparative Example 1, the activation temperature of Comparative Example 2 is increased to 620℃, and the toluene purification efficiency of the deodorant finally prepared is decreased from 86.2% (Comparative Example 1) to 84.6% (Comparative Example 2), which shows that too high activation temperature (620℃) will lead to the decrease of toluene purification performance of the prepared deodorant.
[0048] This is mainly because, originally with the increase of activation temperature, the volatile organic matter inside the vermicompost gradually pyrolysis, the content of fixed carbon gradually increased, while zinc chloride and phosphoric acid can promote the pore development of vermicompost, further open the pore and form fixed pore structure, and then improve the adsorption capacity, that is, improve the toluene purification performance. However, when the temperature continues to rise (higher than 600℃), the carbon content in the vermicompost is burned seriously, the ash gradually increases, in addition, high temperature will lead to high steam pressure of zinc chloride, so that the zinc chloride inside the vermicompost reduces, the micropore wall on its surface is burned, forming macropore and mesopore, so that the adsorption capacity decreases, and then leads to the decrease of toluene purification performance.
[0049] Specifically, by comparing Comparative Example 1 and Comparative Example 3, it can be seen that, compared with Comparative Example 1 (activation temperature 600℃), the toluene purification efficiency of the deodorant prepared in Comparative Example 3 (activation temperature 600℃) increases from 86.2% (Comparative Example 1) to 87.4% (Comparative Example 3), which indicates that the increase of boric acid in the activator can improve the toluene purification performance of the prepared deodorant. By comparing Comparative Example 2 and Comparative Example 4, it can be seen that, compared with Comparative Example 2 (activation temperature 620℃), the toluene purification efficiency of the deodorant prepared in Comparative Example 4 (activation temperature 620℃) increases from 84.6% (Comparative Example 2) to 88.5% (Comparative Example 4), which is obviously higher than that of Comparative Example 3. This indicates that the increase of boric acid in the activator and the higher activation temperature (620℃) can produce a synergistic effect, which can further improve the toluene purification performance of the prepared deodorant.
[0050] Specifically, by comparing Comparative Example 3 and Comparative Example 5, it can be seen that, compared with Comparative Example 3 (activation temperature 600℃), the toluene purification efficiency of the deodorant prepared in Comparative Example 5 (activation temperature 600℃) increases from 87.4% (Comparative Example 3) to 89.5% (Comparative Example 5), which indicates that the increase of cetyltrimethylammonium bromide in the composite activator can further improve the toluene purification performance of the prepared deodorant. By comparing Comparative Example 4 and Example 1, it can be seen that, compared with Comparative Example 4 (activation temperature 620℃), the toluene purification efficiency of the deodorant prepared in Example 1 (activation temperature 620℃) increases from 88.5% (Comparative Example 4) to 91.4% (Example 1), which is greater than the increase between Comparative Example 5 and Comparative Example 3.
[0051] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present application.
[0052] Furthermore, the various embodiments can also be combined, if not in contradiction, as long as they do not deviate from the spirit of the present application, which should be considered as disclosed.
Claims
1. A method for preparing a deodorant for purifying paint waste gas, characterized in that: The steps include: S1. Mix dry earthworm castings and activator in a mass ratio of 2:1, soak at 80°C for 24 hours, filter and dry to constant weight, then place in an activation furnace, heat to 620±2°C, and activate for 2 hours to obtain activated earthworm castings; S2, soaking the activated earthworm castings obtained in S1 in dilute hydrochloric acid for 30-32 minutes, filtering, rinsing until neutral, drying, crushing and passing through a 50-mesh sieve to obtain inorganic modified earthworm castings; S3, take 30g of the inorganic modified earthworm castings obtained in S2, place it in a conical flask, add 290-300mL of concentrated sulfuric acid, stir and react for 3h, filter, wash until neutral, and dry to obtain a sulfonated product; S4, the sulfonated product obtained in S3 was mixed with 740-760 mL of the composite active agent, stirred at 30° C. for 3 h, filtered, washed, dried, crushed and passed through a 50-mesh sieve to obtain the deodorant for purifying paint exhaust gas; The activator is a mixed aqueous solution of zinc chloride, phosphoric acid and boric acid; and the composite active agent is a mixed aqueous solution of chitosan hydrochloride and cetyltrimethylammonium bromide.
2. The method for preparing a deodorant for purifying paint waste gas according to claim 1, characterized in that: In S1, the method for processing the dried earthworm castings is: airing the earthworm castings until they are loose, and then drying them at 100-105° C. for 3-3.5 hours to obtain the dried earthworm castings.
3. The method for preparing a deodorant for purifying paint waste gas according to claim 1, characterized in that: The activator is prepared by mixing 2 mol / L zinc chloride solution, 2 mol / L phosphoric acid solution and 2 mol / L boric acid solution in a volume ratio of 1:1.7:(0.3-0.5).
4. The method for preparing a deodorant for purifying paint waste gas according to claim 1, characterized in that: In S1, the heating rate is 18-20°C / min.
5. The method for preparing a deodorant for purifying paint waste gas according to claim 1, characterized in that: In S2, the concentration of dilute hydrochloric acid is 2.8-3.2 mol / L.
6. The method for preparing a deodorant for purifying paint waste gas according to claim 1, characterized in that: In S3, the mass fraction of concentrated sulfuric acid is 64-67%.
7. The method for preparing a deodorant for purifying paint waste gas according to claim 1, characterized in that: The preparation method of the composite active agent is as follows: 28-29.5 g of chitosan hydrochloride and 1.8-2.1 g of hexadecyltrimethylammonium bromide are dissolved in water and the volume is adjusted to 1000 mL to obtain the composite active agent.
8. A deodorant for purifying paint waste gas, characterized in that: The method is as described in any one of claims 1 to 7.