A modified adsorbent and a noble metal-supported modified adsorbent, their preparation methods and applications
By modifying the surface functional groups and loading noble metals, the surface functional groups and pore structure of HZSM-5 are improved, which solves the mechanical weaknesses and low efficiency of existing adsorbents in treating CVOCs, and achieves high efficiency and low cost CVOCs adsorption.
Patent Information
- Application Number
- CN202410220451.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-28
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2044-02-28
AI Technical Summary
Existing adsorbents suffer from poor mechanical quality, difficulty in reusing, low adsorption capacity, and low efficiency when treating chlorinated volatile organic compounds (CVOCs), especially commercial molecular sieve adsorbents, which are not effective in treating CVOCs.
By modifying the hydrogen-type zeolite molecular sieve HZSM-5 to change its surface functional group composition and pore structure, and loading a small amount of metallic ruthenium, a modified adsorbent was prepared. NaBH4 was used to reduce Ru3+ to the support surface to form Ru-O bonds, thereby enhancing the adsorption performance.
This improved the adsorption capacity and efficiency of adsorbents for CVOCs, reduced costs, and significantly enhanced the adsorption performance of commercial molecular sieves.
Smart Images
Figure CN117861714B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of chemical catalyst synthesis and its application, and particularly relates to a modified adsorbent, a noble metal loaded modified adsorbent and a preparation method and application thereof. BACKGROUND
[0002] Volatile organic compounds (VOCs) are important precursors of O3, and are also important components of pollutant emissions of industrial enterprises, so the removal of VOCs and nitrogen oxides is crucial to reduce the concentration of O3 in the air.
[0003] For different concentrations of active VOCs of industrial enterprises, the simplest treatment method is generally the adsorption method. This method has low sensitivity to VOCs concentration and can eliminate VOCs of different concentrations. Compared with general VOCs such as benzene series, formaldehyde and alcohol, chlorine-containing VOCs (CVOCs) are less used as targets in related emission enterprises, and the study on the adsorption of CVOCs is also less. In addition, most existing enterprises use assembled activated carbon as their adsorbent, which has the defects of poor mechanical quality, easy to break and difficult to reuse although it has a wide range of adaptation. Thirdly, the molecular sieve adsorbent sold on the market has the problems of low adsorption capacity and poor efficiency, so it is important to synthesize and modify inorganic molecular sieve adsorbents for the adsorption of CVOCs and the reduction of the use cost of adsorption materials. SUMMARY
[0004] The present application aims to provide a modified adsorbent, a noble metal loaded modified adsorbent and a preparation method and application thereof. The adsorbent is a ZSM-5 initial adsorbent purchased on the market which is improved by a small amount of chemical reagent, and the surface functional group composition and pore structure of the adsorbent are changed. A small amount of ruthenium can also be loaded to further strengthen the chemical adsorption of the adsorbent to CVOCs. The prepared modified adsorbent and noble metal loaded modified adsorbent have low cost and high efficiency, and greatly improve the adsorption capacity of commercial molecular sieves.
[0005] The present application provides a modified adsorbent, which is hydrogen type zeolite molecular sieve HZSM-5 or 2XHZSM-5 with improved pore structure of HZSM-5 treated by 2% NaBH4.
[0006] The present application provides a noble metal loaded modified adsorbent, which takes hydrogen type zeolite molecular sieve HZSM-5 as a carrier, and loads Ru on the surface of the carrier by reduction of NaBH4 3+ The mass fraction of Ru in the carrier HZSM-5 is 1%, and the mass of NaBH4 accounts for 2% of the mass of the noble metal loaded modified adsorbent.
[0007] This invention provides a method for preparing a modified adsorbent, comprising the following steps:
[0008] S1. Preparation of hydrogen-type zeolite molecular sieve HZSM-5;
[0009] S2. Disperse the prepared hydrogen-type zeolite molecular sieve HZSM-5 in deionized water by ultrasonic dispersion to obtain a suspension.
[0010] S3. Dissolve NaBH4 in water, add it dropwise to the suspension obtained in step S2 and stir to obtain the suspension after reaction;
[0011] S4. After filtering, washing, and drying the suspension from step S3, calcine it in air to obtain the desired modified adsorbent.
[0012] Preferably, the specific steps of step S1 are as follows: tetraethyl orthosilicate, sodium aluminate, and tetrapropylammonium hydroxide are dissolved in deionized water, stirred, and sodium alginate is added and stirred. Then, the mixture is placed in a reaction vessel for hydrothermal reaction, filtered and washed, dried overnight, and calcined to obtain a solid. An ammonium chloride solution is used for ion exchange at a solid-liquid ratio of 1g:20ml. The mixture is subjected to a water bath, exchanged three times, washed and filtered, dried overnight, and then calcined.
[0013] Preferably, the specific steps of step S3 are as follows: 10 mg of NaBH4 is dissolved in 50 mL of water, added dropwise to the suspension obtained in step S2 and stirred; the drying temperature in step S4 is 100 °C and the drying time is 3 h; the calcination temperature is 550 °C and the calcination time is 3 h.
[0014] This invention provides a method for preparing a noble metal-supported modified adsorbent, comprising the following steps:
[0015] S1. Preparation of hydrogen-type zeolite molecular sieve HZSM-5;
[0016] S2. Disperse the prepared hydrogen-type zeolite molecular sieve HZSM-5 in deionized water by ultrasonic dispersion to obtain a suspension.
[0017] S3, containing Ru 3+ The solution was added dropwise to the suspension obtained in step S2 and stirred to obtain a solution containing Ru. 3+ ; a suspension;
[0018] S4. Dissolve NaBH4 in water and add it dropwise to the solution containing Ru obtained in step S3. 3+ The suspension was stirred and reacted to obtain the reacted suspension;
[0019] S5. Filter, wash, dry, and calcine the reaction suspension obtained in step S4 in an air atmosphere to obtain the desired noble metal-loaded modified adsorbent.
[0020] Preferably, the specific steps of step S1 are as follows: tetraethyl orthosilicate, sodium aluminate, and tetrapropylammonium hydroxide are dissolved in deionized water, stirred, and sodium alginate is added and stirred. Then, the mixture is placed in a reaction vessel for hydrothermal reaction, filtered and washed, dried overnight, and calcined to obtain a solid. An ammonium chloride solution is used for ion exchange at a solid-liquid ratio of 1g:20ml. The mixture is subjected to a water bath, and after three exchanges, it is washed, filtered, dried overnight, and then calcined.
[0021] Preferably, the specific step in step S3 is as follows: adding Ru, which accounts for 1% of the mass of HZSM-5. 3+ Add to the suspension obtained in step S2 and stir; the specific steps in step S4 are as follows: dissolve 10 mg of NaBH4 in 50 mL of water, and add dropwise the solution containing Ru obtained in step S3. 3+ The suspension is stirred; the drying temperature in step S4 is 100℃ and the drying time is 3h; the calcination temperature is 550℃ and the calcination time is 3h.
[0022] This invention provides an application of a modified adsorbent in the adsorption of p-chlorobenzene.
[0023] This invention provides an application of a noble metal-supported modified adsorbent in the adsorption of p-chlorobenzene.
[0024] Therefore, this invention employs the aforementioned modified adsorbent and noble metal-supported modified adsorbent, along with their preparation methods and applications. This adsorbent is superior to the commercially available ZSM-5 adsorbent. Its adsorption performance can be further improved through small-scale chemical reagent modifications, altering its surface functional group composition and pore structure. Furthermore, a small amount of ruthenium can be loaded to further enhance the chemisorption of CVOCs. The prepared modified adsorbent and noble metal-supported modified adsorbent are low-cost, highly efficient, and significantly improve the adsorption capacity of commercial molecular sieves.
[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0027] Figure 1 The images show the adsorption curves of chlorobenzene for the adsorbents synthesized in Examples 1 and 2 and the commercial adsorbent of Comparative Example 1. The chlorobenzene concentration was 1000 ppm, the space velocity was 15000 mL / (gh), the amount of adsorbent used was 0.1 g, and the adsorption temperature was 30 °C.
[0028] Figure 2The images show the adsorption curves of p-chlorobenzene for one adsorbent synthesized in Example 2 and two adsorbents synthesized in Example 3. The chlorobenzene concentration was 1000 ppm, the space velocity was 15000 mL / (gh), the amount of adsorbent used was 0.1 g, and the adsorption temperature was 30 °C.
[0029] Figure 3 The images show the adsorption curves of chlorobenzene for 2X1RuHZSM-5 synthesized in Example 3 and 1Ru2XHZSM-5 synthesized in Example 4. The chlorobenzene concentration was 1000 ppm, the space velocity was 15000 mL / (gh), the amount of adsorbent used was 0.1 g, and the adsorption temperature was 30 °C. Detailed Implementation
[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0031] This invention provides a modified adsorbent, which is a hydrogen-type zeolite molecular sieve HZSM-5 or 2XHZSM-5 with improved pore structure by treating HZSM-5 with 2% NaBH4.
[0032] This invention provides a noble metal-supported modified adsorbent, which uses hydrogen-form zeolite molecular sieve HZSM-5 as a support and is generated by reducing the supported Ru with NaBH4. 3+ The Ru content is 1% of the mass fraction of the carrier HZSM-5, and the NaBH4 content is 2% of the mass of the noble metal-loaded modified adsorbent.
[0033] This invention provides a method for preparing a modified adsorbent, comprising the following steps:
[0034] S1. Preparation of hydrogen-type zeolite molecular sieve HZSM-5: 33.6 ml tetraethyl orthosilicate, 0.49182 g sodium aluminate, and 9 ml tetrapropylammonium hydroxide were dissolved in 108 ml deionized water. The mixture was stirred and 0.4 g sodium alginate was added and stirred. The mixture was then placed in a reaction vessel and hydrothermally reacted at 140 °C for 48 h. After filtration and washing, the mixture was dried at 100 °C overnight and calcined at 550 °C for 3 h to obtain a solid. Ion exchange was performed using 0.4 mol / L ammonium chloride solution at a solid-liquid ratio of 1 g: 20 ml in an 80 °C water bath for 3 h. After three ion exchange cycles, the mixture was washed and filtered. After drying at 100 °C overnight, the mixture was calcined at 550 °C for 3 h.
[0035] S2. Disperse 0.5g of the prepared hydrogen-type zeolite molecular sieve HZSM-5 in 100mL of deionized water by ultrasonic dispersion to obtain a suspension;
[0036] S3. Dissolve 10 mg of NaBH4 in 50 mL of water, add it dropwise to the suspension obtained in step S2 and stir to obtain the suspension after reaction.
[0037] S4. Filter the suspension after the reaction in step S3, wash it, dry it at 100°C for 3 hours, and then calcine it in air at 550°C for 3 hours to obtain the desired modified adsorbent.
[0038] This invention provides a method for preparing a noble metal-supported modified adsorbent, comprising the following steps:
[0039] S1. Preparation of hydrogen-type zeolite molecular sieve HZSM-5: 33.6 ml tetraethyl orthosilicate, 0.49182 g sodium aluminate, and 9 ml tetrapropylammonium hydroxide were dissolved in 108 ml deionized water. The mixture was stirred and 0.4 g sodium alginate was added and stirred. The mixture was then placed in a reaction vessel and hydrothermally reacted at 140 °C for 48 h. After filtration and washing, the mixture was dried at 100 °C overnight and calcined at 550 °C for 3 h to obtain a solid. Ion exchange was performed using 0.4 mol / L ammonium chloride solution at a solid-liquid ratio of 1 g: 20 ml in an 80 °C water bath for 3 h. After three ion exchange cycles, the mixture was washed and filtered. After drying at 100 °C overnight, the mixture was calcined at 550 °C for 3 h.
[0040] S2. Disperse 0.5g of the prepared hydrogen-form zeolite molecular sieve HZSM-5 into 100mL of deionized water by ultrasonic dispersion to obtain a suspension;
[0041] S3, add Ru, which accounts for 1% of the mass of HZSM-5. 3+ Add to the suspension obtained in step S2 and stir to obtain a solution containing Ru. 3 + ; a suspension;
[0042] S4. Dissolve NaBH4 in water and add it dropwise to the solution containing Ru obtained in step S3. 3+ The suspension was stirred and reacted to obtain the reacted suspension;
[0043] S5. Filter the reaction suspension obtained in step S4, wash it, dry it at 100°C for 3 hours, and then calcine it in air at 550°C for 3 hours to obtain the modified adsorbent supported on the desired noble metal.
[0044] This invention provides an application of a modified adsorbent in the adsorption of p-chlorobenzene.
[0045] This invention provides an application of a noble metal-supported modified adsorbent in the adsorption of p-chlorobenzene.
[0046] Example 1
[0047] Zeolite molecular sieve adsorbent HZSM-5 was prepared by hydrothermal method and named zeolite molecular sieve adsorbent HZSM-5 according to its molar composition: 33.6 ml tetraethyl orthosilicate + 0.49182 g sodium aluminate + 9 ml tetrapropylammonium hydroxide were dissolved in 108 ml deionized water and stirred for 60 min. 0.4 g sodium alginate was added and stirred for 12 h. The mixture was placed in a reaction vessel and hydrothermally reacted at 140 °C for 48 h. After filtration and washing, the mixture was dried at 100 °C overnight and calcined at 550 °C for 3 h at a rate of 5 °C / min to obtain a solid. Ion exchange was performed using 0.4 mol / L ammonium chloride solution at a solid-liquid ratio of 1 g: 20 ml in an 80 °C water bath for 3 h. After three ion exchange cycles, the mixture was washed and filtered, dried at 100 °C overnight, and then calcined at 550 °C for 3 h at a rate of 5 °C / min to obtain zeolite molecular sieve HZSM-5. The zeolite molecular sieve was then compressed into tablets, sieved (40-60 mesh), and set aside for use.
[0048] Example 2
[0049] Take 0.5 g of the product from Example 1, add 100 ml of deionized water, and sonicate for 1 h to obtain a suspension; disperse 10 mg of NaBH4 in 50 ml of deionized water, add it dropwise to the obtained suspension and stir for 1 h; then filter, wash, and dry at 100 °C for 3 h; calcine at 550 °C for 3 h at a rate of 5 °C / min to obtain modified adsorbent 2XHZSM-5; compress into tablets, sieve (40-60 mesh) and set aside for use.
[0050] Example 3
[0051] Take 0.5 g of the product from Example 1, add 100 ml of deionized water, sonicate for 1 h, add 1 wt% RuCl3 according to the concentration of the prepared RuCl3 solution (2 mg / mL), stir for 1 h, and obtain a product containing Ru. 3+ The suspension was prepared by dispersing 10 mg or 30 mg of NaBH4 in 50 ml of deionized water and adding it dropwise to the solution containing Ru from the previous step. 3+ In the suspension, stir for 1 hour, filter, wash, dry at 100℃ for 3 hours, and calcine at 550℃ for 3 hours at a rate of 5℃ / min to obtain the noble metal-loaded modified adsorbent 2X1RuHZSM-5 (corresponding to 10mg NaBH4) or 6X1RuHZSM-5 (corresponding to 30mg NaBH4); compress into tablets, sieve (40-60 mesh) and set aside for use.
[0052] Example 4
[0053] Take 0.5g of the product from Example 1, add 100ml of deionized water, sonicate for 1h, disperse 10mg NaBH4 in 50ml of deionized water, stir for 1h, add 1wt% RuCl3 according to the concentration of the prepared RuCl3 solution (2mg / mL), stir for 1h, filter, wash, dry at 100℃ for 3h, calcine at 550℃ for 3h at a rate of 5℃ / min to obtain the noble metal-loaded modified adsorbent 1Ru2X HZSM-5; compress into tablets, sieve (40-60 mesh) for later use.
[0054] Example 5
[0055] The adsorption capacity of the adsorbent for chlorobenzene was evaluated using a fixed-bed reactor and a gas chromatograph. 100 mg of sample (40-60 mesh) was placed in a quartz tube with an inner diameter of 6 mm. The gas flow was stabilized by packing the front and back of the adsorbent with quartz wool and quartz sand. The gas flowed from the top to the bottom of the quartz tube, and the temperature of the adsorbent bed was measured by a thermocouple from the bottom of the tube. The chlorobenzene concentration was controlled by a gas generator, where liquid chlorobenzene was bubbled into the adsorption system to purge volatilized chlorobenzene. The concentration was controlled by the bubbler temperature and the purge flow rate to achieve a chlorobenzene volume concentration of 1000 ppm and a total flow rate of 25 mL / min.
[0056] Comparative Example 1
[0057] Purchased commercial ZSM-5 adsorbent.
[0058] Figure 1 These are the adsorption curves of chlorobenzene for the adsorbents synthesized in Examples 1 and 2 and the commercial adsorbent of Comparative Example 1. The horizontal axis represents adsorption time in minutes (min), and the vertical axis, C / C0, represents the ratio of the chlorobenzene concentration in the tail gas to the initial concentration. The adsorption performance of the adsorbent is generally represented by the time required for C / C0 = 0.05; a longer time indicates better adsorption performance. Figure 1 It can be seen that the adsorption capacity of the self-made HZSM-5 in Example 1 is better than that of the commercial ZSM-5. After modification, the adsorbent 2XHZSM-5 synthesized in Example 2 has better adsorption performance than the self-made HZSM-5. After two modifications, the adsorption capacity of the three adsorbents is improved accordingly. The adsorption performance of the three adsorbents from largest to smallest is 2XHZSM-5 (C / CO = 0.05, 55 min) > HZSM-5 (C / CO = 0.05, 33 min) > ZSM-5 (C / CO = 0.05, 2 min). The adsorbent synthesized in Example 2 has the best performance.
[0059] Figure 2The images show the adsorption curves of p-chlorobenzene for one adsorbent synthesized in Example 2 and two adsorbents synthesized in Example 3. This was done to investigate the effect of the amount of NaBH4 added on the adsorption performance under the same noble metal loading. Figure 2 It can be seen that the adsorbent 2X1RuHZSM-5 synthesized in Example 3 has higher adsorption performance than the adsorbent 2XHZSM-5 synthesized in Example 2, indicating that the addition of noble metals can promote the improvement of adsorption performance. The effect of NaBH4 addition amount on adsorption performance was also investigated. As shown in the figure, the adsorbent 2X1RuHZSM-5 (10 mg NaBH4) synthesized in Example 3 has better adsorption performance than 6X1RuHZSM-5 (30 mg NaBH4). The adsorption performance of the three adsorbents from highest to lowest is: 2X1RuHZSM-5 (C / C0 = 0.05, 78 min) > 6X1RuHZSM-5 (C / C0 = 0.05, 64 min) > 2XHZSM-5 (C / C0 = 0.05, 55 min).
[0060] Figure 3 The images show the adsorption curves of chlorobenzene for two adsorbents synthesized in Example 3 (2X1RuHZSM-5) and Example 4 (1Ru2X HZSM-5), used to investigate the effect of the order of addition of NaBH4 and RuCl3 on the adsorption performance. Figure 3 It can be seen that the adsorbent 2X1RuHZSM-5 synthesized in Example 3 has higher adsorption performance than the adsorbent 1Ru2XHZSM-5 synthesized in Example 4. This indicates that the noble metal precursor RuCl3 needs to be added in advance to complete pre-adsorption before reduction and bonding by NaBH4. If NaBH4 is added in advance before RuCl3 is added, the effect is poor. The adsorption performance of the two adsorbents from largest to smallest is 2X1RuHZSM-5 (C / CO = 0.05, 78 min) > 1Ru2XHZSM-5 (C / CO = 0.05, 52 min).
[0061] Table 1 shows the BET specific surface area, pore volume, and average pore size of the five adsorbents synthesized in Examples 1, 2, and 3, and the comparative example commercial ZSM-5, totaling six adsorbents. These data were measured using a V-Sorb 4804TP physical adsorption analyzer manufactured by Beijing Guoyi Precision Measurement Technology Co., Ltd. (Table 1 and...) Figure 1 , Figure 2It can be seen that although the adsorption performance of HZSM-5 was improved by NaBH4 treatment (2XHZSM-5) or by loading noble metals (2X1RuHZSM-5), the specific surface area, pore volume, and average pore size all showed a decreasing trend. This indicates that the improvement in adsorption performance is not strongly correlated with physical properties such as specific surface area and pore volume. This is because the addition of NaBH4 changed the acidic site composition of HZSM-5, thus improving its adsorption of chlorobenzene. Further loading with the noble metal Ru enhanced the chemical adsorption of CVOCs and the adsorbent. Under the action of NaBH4, Ru and O on the support surface formed structurally stable Ru-O bonds, enhancing the surface RuO bond. x The electronic interaction between the species and the carrier enhances acidity, thereby strengthening the chemisorption of chlorobenzene. For cost reasons, molecular sieve adsorbents with higher adsorption performance than commercially available molecular sieves can be produced simply by modifying the sieve with chemical reagents, without loading precious metals.
[0062] Table 1. Comparison of the performance of various adsorbents
[0063]
[0064] Therefore, this invention provides a modified adsorbent and a noble metal-supported modified adsorbent, their preparation methods, and applications. By treating the pore structure and surface functional groups of the synthesized zeolite molecular sieve HZSM-5 with NaBH4, 2XHZSM-5 is obtained, which is beneficial to improving the adsorption capacity of the molecular sieve for CVOCs. Furthermore, by reducing Ru in RuCl3 supported by NaBH4... 3+ The modified adsorbent is then calcined at high temperature to form 2X1RuHZSM-5 on the surface of the molecular sieve, which can further enhance the adsorption capacity of the adsorbent for CVOCs. The modified adsorbent and the noble metal-supported modified adsorbent prepared are low in cost and high in efficiency, which greatly improves the adsorption capacity of commercial molecular sieves.
[0065] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A modified adsorbent characterized by: The modified adsorbent is 2% NaBH4 treated 2XHZSM-5 with improved pore structure of HZSM-5; The preparation method of the modified adsorbent comprises the following steps: S1, preparing hydrogen type zeolite molecular sieve HZSM-5; The specific steps of S1 are as follows: tetraethyl orthosilicate, sodium aluminate and tetrapropylammonium hydroxide are dissolved in deionized water, stirring and adding sodium alginate for stirring, then putting into a reaction kettle, hydrothermal reaction, filtering and washing, drying overnight, calcining to obtain solid, ion exchange with an ammonium chloride solution according to a solid-liquid ratio of 1g:20ml, water bath, washing and suction filtering after three times of exchange, drying overnight, and calcining. S2, dispersing the prepared hydrogen type zeolite molecular sieve HZSM-5 into deionized water for ultrasonic dispersion to obtain a suspension; S3, dissolving NaBH4 in water, adding into the suspension obtained in step S2 drop by drop and stirring to obtain a reacted suspension; S4, filtering, washing and drying the reacted suspension in step S3, and calcining in an air atmosphere to obtain the required modified adsorbent.
2. The method of claim 1 wherein the modified adsorbent is prepared by the steps of: comprises the following steps: S1, preparing hydrogen type zeolite molecular sieve HZSM-5; The specific steps of S1 are as follows: tetraethyl orthosilicate, sodium aluminate and tetrapropylammonium hydroxide are dissolved in deionized water, stirring and adding sodium alginate for stirring, then putting into a reaction kettle, hydrothermal reaction, filtering and washing, drying overnight, calcining to obtain solid, ion exchange with an ammonium chloride solution according to a solid-liquid ratio of 1g:20ml, water bath, washing and suction filtering after three times of exchange, drying overnight, and calcining. S2, dispersing the prepared hydrogen type zeolite molecular sieve HZSM-5 into deionized water for ultrasonic dispersion to obtain a suspension; S3, dissolving NaBH4 in water, adding into the suspension obtained in step S2 drop by drop and stirring to obtain a reacted suspension; S4, filtering, washing and drying the reacted suspension in step S3, and calcining in an air atmosphere to obtain the required modified adsorbent.
3. The method of claim 2, wherein the modified adsorbent is prepared by the steps of: The specific steps of step S3 are as follows: 10 mg of NaBH4 is dissolved in 50 mL of water, added into the suspension obtained in step S2 drop by drop and stirred; the drying temperature in step S4 is 100 DEG C, the drying time is 3 h; the calcining temperature is 550 DEG C, and the calcining time is 3 h.
4. Application of the modified adsorbent in claim 1 in adsorption of p-chlorobenzene.