CeO2@CoMn-LDHs composite photothermal catalyst, and preparation method and application thereof

Abstract

The application discloses a CeO2@CoMn-LDHs composite photothermal catalyst and a preparation method and application thereof, and belongs to the technical field of catalyst preparation. The modified agent with excellent thermal catalysis and photocatalysis capacity is prepared by multifunctional design and assembly of LDHs. First, the transition metal elements Co and Mn with high catalytic activity are introduced into the LDHs to enhance the photocatalytic activity of the LDHs; second, the anionic ultraviolet absorber is replaced into the interlayer of the CoMn-LDHs by an ion exchange method, the CoMn-LDHs are modified organically, and the CoMn-LDHs are endowed with the ultraviolet aging resistance; finally, the CeO2 with thermal catalytic capacity is loaded on the surface of the LDHs to realize preparation of the LDHs composite material with the thermal catalysis and photocatalysis capacity. The prepared CeO2@CoMn-LDHs composite photothermal catalyst is used for asphalt materials, can not only improve the performance of the asphalt materials, inhibit the generation of asphalt fume, but also catalyze degradation of automobile exhaust, and realizes green environmental protection of the asphalt pavement.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and specifically relates to a CeO2@CoMn-LDHs composite photothermal catalyst and a preparation method and application thereof. Background Art

[0002] Asphalt pavement is increasingly being used due to its excellent road performance. However, due to its extremely complex composition, asphalt releases pungent, toxic fumes when exposed to high temperatures during production, mixing, paving, and service, posing a serious threat to human health. The widespread use of asphalt pavement has also led to a surge in the number of motor vehicles, generating significant amounts of exhaust that has a significant impact on the natural environment and human health.

[0003] Photothermal catalytic materials are a type of catalyst that uses natural light or heat to degrade toxic and harmful pollutants into harmless components such as CO2 and H2O, without changing themselves. Currently, catalytic materials used for asphalt modification primarily utilize natural light to degrade pollutants, such as TiO2 (CN108752951A) and g-C3N4 (CN107051569A). However, photocatalytic materials are highly dependent on the environment and cannot fully demonstrate their effectiveness in low-light environments, such as on rainy days and at night. Furthermore, asphalt materials are affected by light and heat during their service life. Asphalt, being a black, heat-absorbing material, heats up rapidly under the influence of light and heat. In the summer, the temperature of asphalt pavement can even reach 60-70°C, providing an ideal reaction environment for thermal catalysis. Therefore, in addition to photocatalytic properties, catalytic materials used for asphalt modification should also possess thermal catalytic capabilities. The present invention comprehensively considers the service environment of asphalt materials and develops a catalytic material with good photothermal synergy, which eliminates the pollution caused by asphalt materials during use and the harm of automobile exhaust to the human body and the natural environment, providing technical support for green and environmentally friendly asphalt pavement. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a CeO2@CoMn-LDHs composite photothermal catalyst for road asphalt to obtain a material with the ability to remove odor and suppress smoke, degrade automobile exhaust and improve the anti-aging ability of asphalt roads.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The application discloses a CeO2@CoMn-LDHs composite photo-thermal catalyst, which is composed of Co(NO3)2.6H2O, Mn(NO3)2.4H2O, an anionic intercalation modifier and a rare earth material, wherein the mass fractions of the Co(NO3)2.6H2O, the Mn(NO3)2.4H2O, the anionic intercalation modifier and the rare earth material are 30-45 parts, 10-15 parts, 10-25 parts and 30-35 parts respectively.

[0007] The CoMn-LDHs is prepared by coprecipitation with Co(NO3)2.6H2O and Mn(NO3)2.4H2O as raw materials, deionized water as a solvent and a washing agent.

[0008] The anionic intercalation modifier is any one of terephthalic acid, p-aminobenzoic acid and sodium molybdate.

[0009] The rare earth material is nano CeO2.

[0010] The preparation method of the CeO2@CoMn-LDHs composite photo-thermal catalyst comprises the following steps:

[0011] 1) Co(NO3)2.6H2O and Mn(NO3)2.4H2O are dissolved in deionized water, then the solution is uniformly stirred to obtain solution A, and an anionic intercalation modifier is added into deionized water to prepare solution B;

[0012] 2) under the condition of an oil bath at 60 DEG C, the solution A obtained in step 1) is slowly added into the solution B, and a 2 mol / L NaOH solution is used to control the pH value of the mixed solution to be 10; after the addition is completed, the stirring is continued for 30 min, and then aging is carried out for 24 h; the filter cake is vacuum filtered, repeatedly washed, dried and ground into a powder with a particle size of less than 0.075 mm, so as to obtain the anionic intercalation modified LDHs;

[0013] 3) firstly, CeO2 is calcined at 400 DEG C for 2 h to activate the CeO2; after being cooled to room temperature, a certain amount of CeO2 is added into deionized water and stirred with a glass rod until the mixture is fully mixed; then the anionic intercalation modified LDHs obtained in step 2) is added into the mixture, and stirring and ultrasonic treatment are carried out for 15 min each time for two times; the mixture is added into a reaction kettle and heated at 120 DEG C for 12 h; after vacuum filtration, washing and drying, the mixture is ground into a powder with a particle size of less than 0.075 mm, so as to obtain the CeO2@CoMn-LDHs composite photo-thermal catalyst.

[0014] The CeO2@CoMn-LDHs composite photo-thermal catalyst is used for preparing modified asphalt.

[0015] The asphalt is road petroleum asphalt, and the 25 DEG C penetration is 60dmm-100dmm, the softening point is 40-55 DEG C, and the 10 DEG C ductility is 15cm-25cm.

[0016] The preparation method of the CeO2@CoMn-LDHs modified asphalt comprises the following steps: adding the CeO2@CoMn-LDHs composite photo-thermal catalyst into asphalt, and then carrying out melt blending under the condition of 140 DEG C ± 5 DEG C and a shearing rate of 5000rpm for 90min, so that the modified asphalt with excellent smoke suppression, odor removal, tail gas degradation and comprehensive performance is prepared.

[0017] The beneficial effects of the present application are as follows:

[0018] 1) According to the characteristics of the service environment of asphalt pavement, the LDHs is functionally assembled by using the unique layer structure of LDHs. First, the transition metal elements Co and Mn with high catalytic activity are introduced into the LDHs to enhance the photocatalytic activity of the LDHs. At the same time, the CeO2 with thermal catalytic ability is loaded on the surface of the LDHs to prepare the LDHs composite material with thermal catalytic and photocatalytic ability, so as to improve the efficient degradation ability of the asphalt smoke and automobile exhaust, and realize the green environmental protection of the asphalt pavement.

[0019] 2) The anionic ultraviolet absorber is replaced into the interlayer of CoMn-LDHs to modify the LDHs, so as to improve the compatibility and stability of the LDHs composite photo-thermal catalyst in the asphalt, improve the adsorption effect of the LDHs on harmful components, and endow the LDHs with anti-ultraviolet aging ability. The prepared LDHs composite photo-thermal catalyst has anti-photo-oxidative aging ability and anti-thermal-oxidative aging ability, so as to improve the anti-aging ability of the asphalt material and prolong the service life of the asphalt pavement. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the X-ray diffraction (XRD) characterization diagram of the CeO2@CoMn-LDHs composite photo-thermal catalyst obtained from Example 1 of the present application, wherein the (a) curve is the XRD spectrum of CeO2, the (b) curve is the XRD spectrum of LDHs, and the (c) curve is the XRD spectrum of CeO2@CoMn-LDHs.

[0021] Figure 2is a scanning electron microscope (SEM) micro-morphology diagram of the CeO2@CoMn-LDHs composite photocatalyst obtained by Example 3 of the present application.

[0022] Figure 3 is a scanning electron microscope (SEM) micro-morphology diagram of the LDHs obtained by Comparative Example 3 of the present application. DETAILED DESCRIPTION

[0023] In order to better understand the present application, the content of the present application is further illustrated below in combination with examples, but the content of the present application is not limited to the following examples only.

[0024] The preparation method of the CeO2@CoMn-LDHs composite photocatalyst used in the following examples is as follows:

[0025] 1) Dissolve Co(NO3)2·6H2O and Mn(NO3)2·4H2O in deionized water, then uniformly stir the solution to obtain solution A, and add an anionic intercalation modifier to deionized water to configure solution B;

[0026] 2) Under the condition of 60℃ oil bath, slowly drop solution A obtained in step 1) into solution B, and control the pH value of the mixed solution to be 10 by using a 2mol / L NaOH solution. After the dropping is completed, continue to stir for 30min, and then age for 24h. Vacuum filter the filter cake, repeatedly wash, dry, and obtain anion intercalation modified LDHs;

[0027] 3) First, activate CeO2 by calcining CeO2 at 400℃ for 2h, after cooling to room temperature, take a certain amount of CeO2 and add it to deionized water, and stir with a glass rod until fully mixed; then add the anion intercalation modified LDHs obtained in step 2) to the mixture, stir for 15min and ultrasonic for 15min, repeat twice, and add the mixture to a reaction kettle, heat at 120℃ for 12h; after vacuum filtration, washing, drying, and grinding into a powder with a particle size of less than 0.075mm, the CeO2@CoMn-LDHs composite photocatalyst is obtained.

[0028] Example 1

[0029] According to the preparation method steps of the CeO2@CoMn-LDHs composite photocatalyst, the required CeO2@CoMn-LDHs of Example 1 is prepared, wherein the anion intercalation modifier is terephthalic acid, the rare earth material is CeO2, and the mass fractions of each raw material are as follows: 45 parts of Co(NO3)2·6H2O, 15 parts of Mn(NO3)2·4H2O, 10 parts of terephthalic acid, and 30 parts of CeO2.

[0030] Select 99 (25℃ penetration 65dmm, softening point 45℃, 10℃ ductility 22cm) road petroleum asphalt is heated to flow state, then slowly add 1 part of prepared CeO2@CoMn-LDHs under the condition of 140±5℃, shear rate 5000rpm, melt blending 90min, the asphalt material with deodorization and smoke suppression, degradation of automobile exhaust and excellent comprehensive performance can be obtained.

[0031] Comparative Example 1:

[0032] According to the preparation method of CeO2@CoMn-LDHs composite photocatalyst (step 1 does not add terephthalic acid, add appropriate Na2CO3; step 3 does not add CeO2) to LDHs, the same treatment is obtained, that is, the comparative sample of CeO2@CoMn-LDHs in example 1, the comparative sample and asphalt are operated according to the raw material ratio and preparation method described in example 1, and the comparative example 1 of modified asphalt in example 1 is prepared.

[0033] The change of smoke solid particle mass and H2S gas concentration of the modified asphalt samples prepared in example 1 and comparative example 1 is tested by using asphalt smoke collecting device and H2S gas detector respectively, and the degradation of CO, HC and NO three kinds of gas of the modified asphalt samples prepared in example 1 and comparative example 1 is tested by using exhaust purification device system, and the results are as follows:

[0034] Table 1 asphalt smoke mass of different modified asphalt

[0035]

[0036] Table 2 hydrogen sulfide concentration of different modified asphalt

[0037]

[0038] Table 3 purification effect of different modified asphalt on automobile exhaust main components

[0039]

[0040] From the above table, compared with the modified asphalt of comparative example 1, the modified asphalt prepared in example 1 shows good smoke suppression and deodorization effect and more excellent automobile exhaust degradation efficiency.

[0041] Example 2:

[0042] The CeO2@CoMn-LDHs required by Example 2 was prepared according to the preparation method (steps) of the CeO2@CoMn-LDHs composite photocatalyst, wherein the anion intercalation modifier was p-aminobenzoic acid, the rare earth material was CeO2, and the mass fractions of the raw materials were as follows: 40 parts of Co(NO3)2·6H2O, 14 parts of Mn(NO3)2·4H2O, 13 parts of p-aminobenzoic acid, and 33 parts of CeO2.

[0043] 98 parts of road petroleum asphalt (25℃ penetration of 65 dmm, softening point of 45℃, and 10℃ ductility of 22 cm) was selected and heated to a flowable state, and then 2 parts of the prepared CeO2@CoMn-LDHs was slowly added under the condition of 140±5℃ and a shear rate of 5000 rpm for melt blending for 90 min, to obtain asphalt material with excellent deodorizing, smoke suppressing, automobile exhaust degrading, and comprehensive performance.

[0044] Comparative Example 2

[0045] The LDHs was treated in the same way according to the preparation method (step 1 without adding p-aminobenzoic acid and adding an appropriate amount of Na2CO3; step 3 without adding CeO2) of the CeO2@CoMn-LDHs composite photocatalyst, to obtain a comparative sample of the CeO2@CoMn-LDHs in Example 2, and the comparative sample and asphalt were operated according to the raw material ratio and preparation method described in Example 2 to prepare a comparative sample of the modified asphalt in Example 2.

[0046] The changes of the smoke solid particle mass and H2S gas concentration of the modified asphalt samples prepared in Example 2 and Comparative Example 2 were tested by using an asphalt smoke collection device and an H2S gas detector, and the degradation of CO, HC and NO gases of the modified asphalt samples prepared in Example 2 and Comparative Example 2 was tested by using an exhaust gas purification device system, and the results were as follows:

[0047] Table 4 Asphalt smoke mass of different modified asphalts

[0048]

[0049] Table 5 Smoke generation concentration of different modified asphalts

[0050]

[0051] Table 6 Purification effect of different modified asphalts on main components of automobile exhaust

[0052]

[0053] From the above table, compared with the modified asphalt of Comparative Example 2, the modified asphalt prepared in Example 2 exhibits good smoke and odor removal effect and more excellent automobile exhaust degradation efficiency.

[0054] Example 3:

[0055] The CeO2@CoMn-LDHs required for Example 3 was prepared according to the preparation method steps of the CeO2@CoMn-LDHs composite photocatalyst, wherein the anion intercalation modifier was sodium molybdate, the rare earth material was CeO2, and the mass fractions of the raw materials were as follows: 38 parts of Co(NO3)2·6H2O, 13 parts of Mn(NO3)2·4H2O, 15 parts of sodium molybdate, and 34 parts of CeO2.

[0056] 97 parts of road petroleum asphalt (25℃ penetration of 65 dmm, softening point of 45℃, and 10℃ ductility of 22 cm) was selected and heated to a flowable state, then 3 parts of the prepared CeO2@CoMn-LDHs was slowly added under the condition of 140±5℃ and a shear rate of 5000 rpm for melt blending for 90 min, thereby obtaining an asphalt material with excellent smoke and odor removal, automobile exhaust degradation, and comprehensive performance.

[0057] Comparative Example 3:

[0058] The same treatment was performed on the LDHs according to the preparation method of the CeO2@CoMn-LDHs composite photocatalyst (no sodium molybdate was added in step 1, and an appropriate amount of Na2CO3 was added; no CeO2 was added in step 3), thereby obtaining a comparative sample of the CeO2@CoMn-LDHs in Example 3. The comparative sample and the asphalt were operated according to the raw material ratio and the preparation method described in Example 3, thereby preparing a comparative sample of the modified asphalt of Example 3.

[0059] The changes in the mass of solid particles and the concentration of H2S gas of the modified asphalt samples prepared in Example 3 and Comparative Example 3 were tested using an asphalt smoke collection device and an H2S gas detector, respectively. The degradation of CO, HC, and NO gases of the modified asphalt samples prepared in Example 3 and Comparative Example 3 was tested using an exhaust gas purification device system, and the results are as follows:

[0060] Table 7 Mass of asphalt smoke of different modified asphalts

[0061]

[0062] Table 8 Concentration of smoke generated by different modified asphalts

[0063]

[0064] Table 9 Purification effect of different modified asphalts on main components of automobile exhaust

[0065]

[0066] From the above table, compared with the modified asphalt of Comparative Example 3, the modified asphalt prepared in Example 3 exhibits good smoke and odor removal effect and more excellent automobile exhaust degradation efficiency.

[0067] Example 4:

[0068] CeO2@CoMn-LDHs composite photocatalyst was prepared according to the preparation method steps of CeO2@CoMn-LDHs composite photocatalyst, wherein the anion intercalation modifier is terephthalic acid, the rare earth material is CeO2, and the mass fractions of the raw materials are as follows: 33 parts of Co(NO3)2·6H2O, 11 parts of Mn(NO3)2·4H2O, 21 parts of terephthalic acid, and 35 parts of CeO2.

[0069] 96 parts of road petroleum asphalt (25℃ penetration of 65 dmm, softening point of 45℃, and 10℃ ductility of 22 cm) was selected and heated to a flowable state, then 4 parts of the prepared CeO2@CoMn-LDHs was slowly added under the condition of 140±5℃ and shear rate of 5000 rpm for melt blending for 90 min, thereby obtaining asphalt material with excellent smoke and odor removal, automobile exhaust degradation, and comprehensive performance.

[0070] Comparative Example 4:

[0071] CeO2@CoMn-LDHs composite photocatalyst was prepared according to the preparation method of CeO2@CoMn-LDHs composite photocatalyst (no terephthalic acid was added in step 1, and appropriate amount of Na2CO3 was added; no CeO2 was added in step 3), and the same treatment was performed on LDHs, thereby obtaining the comparative sample of CeO2@CoMn-LDHs in Example 4. The comparative sample and asphalt were operated according to the raw material ratio and preparation method described in Example 4, thereby preparing the comparative sample of modified asphalt of Example 4.

[0072] The changes of smoke solid particle mass and H2S gas concentration of the modified asphalt samples prepared in Example 4 and Comparative Example 4 were tested by using an asphalt smoke collection device and an H2S gas detector, respectively. The degradation of CO, HC, and NO gases of the modified asphalt samples prepared in Example 4 and Comparative Example 4 was tested by using an exhaust gas purification device system, and the results are as follows:

[0073] Table 10 Asphalt smoke mass of different modified asphalts

[0074]

[0075] Table 12 Purification effect of different modified asphalts on main components of automobile exhaust

[0076]

[0077] From the above table, compared with the modified asphalt of Comparative Example 4, the modified asphalt prepared in Example 4 exhibits good smoke and odor removal effect and more excellent automobile exhaust degradation efficiency.

[0078] Example 5:

[0079] The CeO2@CoMn-LDHs required for Example 5 was prepared according to the preparation method steps of the CeO2@CoMn-LDHs composite photocatalyst, wherein the anion intercalation modifier was sodium molybdate, the rare earth material was CeO2, and the mass fractions of the raw materials were as follows: 30 parts of Co(NO3)2·6H2O, 10 parts of Mn(NO3)2·4H2O, 25 parts of sodium molybdate, and 35 parts of CeO2.

[0080] 95 parts of road petroleum asphalt (25℃ penetration of 65 dmm, softening point of 45℃, and 10℃ ductility of 22 cm) was selected and heated to a flowable state, then 5 parts of the prepared CeO2@CoMn-LDHs was slowly added under the condition of 140±5℃ and shear rate of 5000 rpm for melt blending for 90 min, thereby obtaining asphalt material with excellent deodorization, smoke suppression, automobile exhaust degradation, and comprehensive performance.

[0081] Comparative Example 5:

[0082] The same treatment was performed on the LDHs according to the preparation method of the CeO2@CoMn-LDHs composite photocatalyst (no sodium molybdate was added in step 1, and an appropriate amount of Na2CO3 was added; no CeO2 was added in step 3), thereby obtaining a comparative sample of the multifunctional CeO2@CoMn-LDHs in Example 5. The comparative sample and the asphalt were operated according to the raw material ratio and preparation method described in Example 5, thereby preparing a comparative sample of the modified asphalt of Example 5.

[0083] The changes in the mass of solid particles and the concentration of H2S gas of the modified asphalt samples prepared in Example 5 and Comparative Example 5 were tested by using an asphalt smoke collection device and an H2S gas detector, respectively. The degradation of CO, HC, and NO gases of the modified asphalt samples prepared in Example 5 and Comparative Example 5 was tested by using an exhaust gas purification device system, and the results are as follows:

[0084] Table 13 Mass of asphalt smoke of different modified asphalts

[0085]

[0086] Table 14 Concentration of smoke generated by different modified asphalts

[0087]

[0088] Table 15 Purification effect of different modified bitumens on main components of automobile exhaust

[0089]

[0090] From the above table, compared with the modified bitumen of Comparative Example 5, the modified bitumen prepared in Example 5 of the present application exhibits good smoke suppression and odor removal effects and more excellent automobile exhaust degradation efficiency.

[0091] Finally, it should be noted that the above is only the preferred embodiments of the present application, the upper and lower limits of each raw material, interval values, can achieve the present application, not listed here.

Claims

1. A method for preparing a CeO2@CoMn-LDHs composite photothermal catalyst, characterized by: Raw materials by mass: 30-45 parts of Co(NO3)2·6H2O, 10-15 parts of Mn(NO3)2·4H2O, 10-25 parts of anionic intercalation modifier, and 30-35 parts of nano-CeO2; The anionic intercalation modifier is one of terephthalic acid, p-aminobenzoic acid, and sodium molybdate; The preparation method comprises the following steps: 1) Dissolve Co(NO3)2·6H2O and Mn(NO3)2·4H2O in deionized water and stir to obtain solution A; add anionic intercalation modifier to deionized water to prepare solution B; 2) In an oil bath at 60°C, solution A was slowly added dropwise to solution B, and the pH of the mixed solution was controlled to be 10 with a 2 mol / L NaOH solution. After the addition was complete, stirring was continued for 30 minutes, followed by aging for 24 hours, vacuum filtration, washing, and drying to obtain anion-intercalated modified LDHs. 3) Nano-CeO2 was calcined at 400°C for 2 h, cooled to room temperature, added to deionized water, and stirred evenly; anion intercalation modified LDHs was added, stirred for 15 min, ultrasonicated for 15 min, repeated twice, and heated at 120°C for 12 h; vacuum filtered, washed, and dried to obtain the CeO2@CoMn-LDHs composite photothermal catalyst.

2. A CeO2@CoMn-LDHs composite photothermal catalyst prepared by the method according to claim 1.

3. An application of the CeO2@CoMn-LDHs composite photothermal catalyst prepared by the method according to claim 1 in modified asphalt, characterized in that: The modified asphalt comprises, by weight, 95 to 99 parts of asphalt and 1 to 5 parts of a CeO2@CoMn-LDHs composite photothermal catalyst. The asphalt is road petroleum asphalt, having a needle penetration of 60 dmm to 100 dmm at 25°C, a softening point of 40 to 55°C, and an elongation of 15 cm to 25 cm at 10°C.

4. The use according to claim 3, characterized in that The preparation method of modified asphalt includes the following steps: adding a CeO2@CoMn-LDHs composite photothermal catalyst to asphalt, melt-blending the mixture at a temperature of 140±5°C and a shear rate of 5000 rpm for 90 minutes to obtain the modified asphalt.

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