Coupling adsorption material containing zeolite and biomass charcoal as well as preparation method and application of coupling adsorption material

Abstract

The invention belongs to the technical field of adsorption materials, and particularly relates to a coupling adsorption material containing zeolite and biomass charcoal as well as a preparation method and application of the coupling adsorption material. The coupling adsorption material is composed of modified zeolite, modified coconut shell biomass charcoal and a silane coupling agent interface bonding layer. After the modified zeolite is modified by three steps of hydrochloric acid, ammonium oxalate and sodium chloride, skeleton exchange sites are unified to be Na < + > type, and the NH < 4 + > interception capability is enhanced; after the modified coconut shell biomass charcoal is oxidized by nitric acid and modified by zirconium oxychloride and phosphoric acid, ammonia nitrogen is removed through multi-mechanism synergy; after two-phase coupling, the ammonia nitrogen removal capability is superior to that of a single component. The silane coupling agent interface bonding layer effectively buffers interface thermal stress generated by mismatching of two-phase thermal expansion coefficients in the high-temperature regeneration process, inhibits microcrack initiation and expansion, guarantees the adsorption capacity stability after multiple regeneration cycles, and prolongs the service life of the material.

Description

Technical Field

[0001] This invention belongs to the field of adsorption material technology, specifically a coupled adsorption material containing zeolite and biochar, its preparation method, and its application. Background Technology

[0002] Ammonia nitrogen is a key pollutant inducing eutrophication in water bodies, and is widely found in domestic sewage, industrial wastewater, and livestock and poultry breeding wastewater. Adsorption methods, due to their simplicity and recyclable materials, have significant engineering application value in the advanced treatment of ammonia nitrogen. Natural zeolites rely on exchangeable cations (Na+) within their framework. + Ca 2+ K + ) and NH4 + Ion exchange enables selective retention; the surface of biochar is rich in oxygen-containing functional groups such as carboxyl and hydroxyl groups, which can remove NH4 through surface complexation and electrostatic adsorption. + Combining the two components allows for a synergistic effect of both mechanisms, resulting in superior ammonia nitrogen removal compared to a single component. Saturated composite materials typically require high-temperature thermal regeneration (>200℃) for NH4 desorption. + To restore adsorption capacity.

[0003] However, zeolites are long-range ordered inorganic aluminosilicate crystals with a linear thermal expansion coefficient ranging from (1 to 10) × 10⁻⁶. - 6 K -1 The range; biochar is a porous amorphous carbon framework, and its coefficient of thermal expansion and degree of anisotropy differ significantly from zeolite. When the two are coupled through physical mixing, the interfacial bonding relies solely on van der Waals forces and mechanical interlocking, resulting in limited bonding strength. During high-temperature regeneration, the two phases experience uncoordinated thermal strain due to the mismatch in their coefficients of thermal expansion, leading to the accumulation of periodic thermal stress at the interface. With repeated regeneration cycles, this stress continues to accumulate and extend towards the bonding layer, ultimately triggering the initiation, propagation, and even macroscopic cracking and peeling of the interfacial microcracks. The structural integrity of the composite material is irreversibly damaged, and NH4... + The adsorption capacity decreases continuously with the number of cycles. Summary of the Invention

[0004] (1) Technical problems to be solved The purpose of this invention is to provide a coupled adsorption material containing zeolite and biochar, its preparation method, and its application, in order to solve the problem that the mismatch in thermal expansion coefficients between the inorganic zeolite crystals and the porous carbon skeleton of biochar leads to interfacial stress concentration during repeated high-temperature regeneration, resulting in cracking and peeling of the combined layer and continuous decay of adsorption capacity.

[0005] (2) Technical solution To achieve the above objectives, on the one hand, the present invention provides a coupled adsorption material containing zeolite and biochar, wherein the coupled adsorption material is composed of modified zeolite, modified coconut shell biochar and a silane coupling agent interfacial bonding layer. The modified zeolite is prepared by modification with hydrochloric acid, ammonium oxalate and sodium chloride; the modified coconut shell biochar is prepared by oxidation with nitric acid, modification with zirconium oxychloride and phosphoric acid; the silane coupling agent interfacial bonding layer is formed by hydrolyzing 3-aminopropyltriethoxysilane and loading it onto the surface of the modified zeolite, and then interacting and bonding with zirconium phosphate on the surface of the modified coconut shell biochar, thereby forming a stable interfacial bonding layer between the modified zeolite and the modified coconut shell biochar.

[0006] Furthermore, the preparation method of the modified zeolite includes the following steps: M11. Soak natural zeolite in a 1 mol / L hydrochloric acid solution; wash with deionized water, then dry and cool to obtain pretreated zeolite; M12. Add the pretreated zeolite to a 1 mol / L ammonium oxalate solution, stir to react, and obtain a zeolite suspension; then wash with deionized water; dry the washed product, heat to react, and then cool naturally to obtain activated zeolite; M13. Add the activated zeolite to a 1 mol / L sodium chloride solution and stir to react. After the reaction is complete, wash with deionized water and then dry to obtain the modified zeolite.

[0007] Further, the particle size of the natural zeolite is 0.5-1 mm; the solid-liquid ratio of the natural zeolite to the 1 mol / L hydrochloric acid solution is 1:5; the solid-liquid ratio of the pretreated zeolite to the 1 mol / L ammonium oxalate solution is 1:7; the solid-liquid ratio of the activated zeolite to the 1 mol / L sodium chloride solution is 1:7; the unit of the solid-liquid ratio is g / mL.

[0008] Furthermore, the preparation method of the modified coconut shell biochar includes the following steps: M21. Wash the coconut shell biochar with deionized water to remove surface dust, and then dry it to obtain pretreated coconut shell biochar; disperse the pretreated coconut shell biochar in a 1 mol / L nitric acid solution and stir; then filter, wash with deionized water, and dry to obtain oxidized pretreated coconut shell biochar. M22. Add the pre-treated coconut shell biochar to a 0.2 mol / L zirconium oxychloride solution, stir and impregnate to obtain coconut shell biochar suspension A; M23. While stirring, sodium hydroxide solution was added dropwise to coconut shell biochar suspension A to adjust the pH of the system; stirring was continued, the mixture was filtered and separated, and washed with deionized water to obtain the coconut shell biochar precursor. M24. The coconut shell biochar precursor was dispersed in a 0.5 mol / L phosphoric acid solution, stirred and reacted, filtered, washed with deionized water, and dried to obtain the dried product. M25. The dried product was placed in a 0.5 mol / L phosphoric acid solution, hydrothermally treated, naturally cooled, filtered, washed with deionized water, and dried to obtain modified coconut shell biochar.

[0009] Further, the coconut shell biochar is 60-80 mesh; the solid-liquid ratio of the pretreated coconut shell biochar to 1 mol / L nitric acid solution is 1:20; the solid-liquid ratio of the oxidized pretreated coconut shell biochar to 0.2 mol / L zirconium oxychloride solution is 1:20; the solid-liquid ratio of the coconut shell biochar precursor to 0.5 mol / L phosphoric acid solution is 1:20; the unit of the solid-liquid ratio is g / mL.

[0010] Based on the same inventive concept, the present invention also provides a method for preparing a coupled adsorption material containing zeolite and biochar, used in the aforementioned coupled adsorption material containing zeolite and biochar, comprising the following steps: M1. Add 3-aminopropyltriethoxysilane to a mixed solution of ethanol and water, adjust the pH with glacial acetic acid, and hydrolyze to obtain a 3-aminopropyltriethoxysilane hydrolysate; M2. The modified zeolite was added to the hydrolysate of 3-aminopropyltriethoxysilane, refluxed, filtered, washed with anhydrous ethanol, and dried to obtain silanized modified zeolite. M3. Silanized modified zeolite and modified coconut shell biochar were dispersed in a mixed solution of ethanol and water, stirred and reacted, and then heat-treated; naturally cooled, washed with deionized water, and dried to obtain a coupled adsorption material containing zeolite and biochar.

[0011] Furthermore, the amount of 3-aminopropyltriethoxysilane used is 3% of the mass of the modified zeolite; the solid-liquid ratio of the total mass of the silanized modified zeolite and the modified coconut shell biochar to the ethanol and water mixed solution is 1:15, and the unit of the solid-liquid ratio is g / mL; the mass ratio of the modified zeolite to the modified coconut shell biochar is 3:1 to 5:1.

[0012] Based on the same inventive concept, the third invention also provides an application of a coupled adsorption material containing zeolite and biochar or a preparation method in the high-temperature thermal regeneration cycle treatment of ammonia nitrogen wastewater.

[0013] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. From the perspective of adsorption performance, modified zeolite, after pretreatment with hydrochloric acid to remove surface impurities and treatment with ammonium oxalate to remove Ca2+ occupying exchange sites in the pores, exhibits the following effects: 2+After three steps of treatment—calcination to activate the pores and sodium chloride solution exchange—the framework ion exchange sites are fully exposed and uniformly converted to Na+. + Type, for NH4 + The selective retention capacity is enhanced. Modified coconut shell biochar, after nitric acid oxidation to increase surface oxygen-containing functional groups and loading with zirconium phosphate, exhibits enhanced surface complexation and electrostatic adsorption, further enhanced by the addition of P-OH and NH4 groups on the zirconium phosphate surface. + H + / NH4 + Ion exchange and adsorption mechanisms have evolved from single-surface complexation to a multi-mechanism synergistic process. After two-phase coupling, three mechanisms emerge—modified zeolite framework Na… + / NH4 + Ion exchange, oxygen-containing functional group surface complexation and electrostatic adsorption, zirconium phosphate H + / NH4 + Ion exchange – working synergistically on the same material, it has a better ammonia nitrogen removal capacity than any single component.

[0014] 2. From the perspective of structural stability, after the coupling agent 3-aminopropyltriethoxysilane hydrolyzes, its silanol groups covalently condense with the modified zeolite surface. The terminal amino groups and zirconium phosphate P-OH form a strong interfacial bond through hydrogen bonding and acid-base interactions. Heat treatment further promotes interfacial densification. This bonding layer upgrades the two-phase connection method from simple physical mixing via van der Waals forces and mechanical interlocking to interfacial bonding with higher bonding strength. This effectively buffers the interfacial thermal stress caused by the mismatch in the thermal expansion coefficients of the two phases during high-temperature regeneration, inhibits the initiation and propagation of microcracks, ensures the structural integrity and adsorption capacity stability of the material after multiple regeneration cycles, and extends the material's service life. Attached Figure Description

[0015] Figure 1 This is a physical image of the modified zeolite of the present invention.

[0016] Figure 2 This is a photograph of the modified coconut shell biochar of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 This embodiment discloses a coupled adsorption material containing zeolite and biochar, wherein the coupled adsorption material is composed of modified zeolite, modified coconut shell biochar and silane coupling agent interfacial bonding layer. The modified zeolite is prepared by modification with hydrochloric acid, ammonium oxalate and sodium chloride; the modified coconut shell biochar is prepared by oxidation with nitric acid, modification with zirconium oxychloride and phosphoric acid; the silane coupling agent interfacial bonding layer is formed by hydrolyzing 3-aminopropyltriethoxysilane and loading it onto the surface of the modified zeolite, and then interacting and bonding with zirconium phosphate on the surface of the modified coconut shell biochar, thereby forming a stable interfacial bonding layer between the modified zeolite and the modified coconut shell biochar.

[0019] The preparation method of the modified zeolite includes the following steps: M11. Add natural zeolite to a 1 mol / L hydrochloric acid solution and soak at room temperature for 2 hours to remove surface carbonates and soluble metal oxide impurities; wash repeatedly with deionized water until the pH of the filtrate is between 6 and 7, then dry at 105℃ for 6 hours and cool to obtain pretreated zeolite. M12. The pretreated zeolite was added to a 1 mol / L ammonium oxalate solution and stirred at 80°C for 4 h to obtain a zeolite suspension. The suspension was then washed with deionized water until the pH of the filtrate stabilized between 6 and 7. The washed product was dried at 105°C for 6 h and then placed in a muffle furnace and heated to 380°C at 5°C / min. After holding at this temperature for 3 h, the product was allowed to cool naturally to obtain activated zeolite. M13. Add the activated zeolite to a 1 mol / L sodium chloride solution and stir at 80°C for 4 hours. After the reaction, wash with deionized water until the pH of the filtrate stabilizes between 6 and 7, then dry at 105°C for 6 hours to obtain the modified zeolite. Figure 1 The image shown is a physical diagram of the modified zeolite of this invention.

[0020] The particle size of the natural zeolite is 0.5-1 mm; the solid-liquid ratio of the natural zeolite to 1 mol / L hydrochloric acid solution is 1:5; the solid-liquid ratio of the pretreated zeolite to 1 mol / L ammonium oxalate solution is 1:7; the solid-liquid ratio of the activated zeolite to 1 mol / L sodium chloride solution is 1:7; the unit of the solid-liquid ratio is g / mL.

[0021] The method for preparing the modified coconut shell biochar includes the following steps: M21. Coconut shell biochar was repeatedly washed with deionized water to remove surface dust, and then dried at 105℃ for 6 hours to obtain pretreated coconut shell biochar. The pretreated coconut shell biochar was dispersed in a 1 mol / L nitric acid solution and stirred at 60℃ for 4 hours. Then it was filtered, washed with deionized water until the pH of the filtrate was between 6 and 7, and dried at 105℃ to constant weight to obtain oxidized pretreated coconut shell biochar. M22. Add the pre-oxidized coconut shell biochar to a 0.2 mol / L zirconium oxychloride solution and stir and soak at room temperature for 6 h to obtain coconut shell biochar suspension A; M23. While stirring, sodium hydroxide solution was added dropwise to coconut shell biochar suspension A to adjust the pH of the system to 8-9; stirring was continued for 1 hour to allow complete precipitation, the mixture was filtered and separated, and washed three times with deionized water to obtain the coconut shell biochar precursor. M24. The coconut shell biochar precursor was dispersed in a 0.5 mol / L phosphoric acid solution and stirred in a 60℃ water bath for 4 h to allow the hydrated zirconium oxide to react with the phosphoric acid to generate an amorphous zirconium phosphate precursor. The precursor was filtered, washed three times with deionized water, and dried at 105℃ to constant weight to obtain the dried product. M25. The dried product was placed in a 0.5 mol / L phosphoric acid solution, transferred to a hydrothermal reactor, and hydrothermally treated at 150℃ for 12 h; after natural cooling, it was filtered, washed three times with deionized water, and dried at 105℃ to constant weight to obtain modified coconut shell biochar. Figure 2 The image shown is a physical picture of the modified coconut shell biochar of the present invention.

[0022] The coconut shell biochar has a mesh size of 60-80 mesh; the solid-liquid ratio of the pretreated coconut shell biochar to 1 mol / L nitric acid solution is 1:20; the solid-liquid ratio of the oxidized pretreated coconut shell biochar to 0.2 mol / L zirconium oxychloride solution is 1:20; the solid-liquid ratio of the coconut shell biochar precursor to 0.5 mol / L phosphoric acid solution is 1:20; the unit of the solid-liquid ratio is g / mL.

[0023] The preparation method of the coupled adsorption material containing zeolite and biochar includes the following steps: M1. Add 3-aminopropyltriethoxysilane to a mixed solution of ethanol and water in a volume ratio of 9:1 to make the mass concentration of 3-aminopropyltriethoxysilane 2.5%~3.5%; adjust the pH to 4~5 with glacial acetic acid, and hydrolyze at 25℃ for 2h to obtain 3-aminopropyltriethoxysilane hydrolysate; M2. The modified zeolite was added to the hydrolysate of 3-aminopropyltriethoxysilane and refluxed at 60°C for 4 hours. After filtration, it was washed three times with anhydrous ethanol and dried at 105°C to constant weight to obtain silanized modified zeolite. M3. The silanized modified zeolite and modified coconut shell biochar were dispersed in a mixed solution of ethanol and water with a volume ratio of 9:1. The mixture was stirred at 60°C for 2 hours and then heat-treated in an oven at 160°C for 4 hours. After natural cooling to room temperature, the mixture was washed three times with deionized water and dried at 105°C to constant weight to obtain a coupled adsorption material containing zeolite and biochar.

[0024] The amount of 3-aminopropyltriethoxysilane used is 3% of the mass of the modified zeolite; the solid-liquid ratio of the total mass of the silanized modified zeolite and the modified coconut shell biochar to the ethanol and water mixed solution is 1:15, and the unit of the solid-liquid ratio is g / mL; the mass ratio of the modified zeolite to the modified coconut shell biochar is 4:1.

[0025] The application of the coupled adsorption material containing zeolite and biochar or its preparation method in the high-temperature thermal regeneration cycle treatment of ammonia nitrogen wastewater.

[0026] Example 2 This embodiment differs from Embodiment 1 in that the mass ratio of modified zeolite to modified coconut shell biochar is 3:1. The other components and preparation methods are the same as in Example 1.

[0027] Example 3 This embodiment differs from Embodiment 1 in that the mass ratio of modified zeolite to modified coconut shell biochar is 5:1. The other components and preparation methods are the same as in Example 1.

[0028] Comparative Example 1 This embodiment differs from Embodiment 1 in that the modified zeolite described in this comparative example is not modified with hydrochloric acid.

[0029] The preparation method of the modified zeolite includes the following steps: M11. Wash the natural zeolite repeatedly with deionized water until the filtrate is clear to remove surface dust, then dry it at 105℃ for 6 hours and cool it to obtain pretreated zeolite. M12. The pretreated zeolite was added to a 1 mol / L ammonium oxalate solution and stirred at 80°C for 4 h to obtain a zeolite suspension. The suspension was then washed with deionized water until the pH of the filtrate stabilized between 6 and 7. The washed product was dried at 105°C for 6 h and then placed in a muffle furnace and heated to 380°C at 5°C / min. After holding at this temperature for 3 h, the product was allowed to cool naturally to obtain activated zeolite. M13. Add the activated zeolite to a 1 mol / L sodium chloride solution and stir at 80°C for 4 h. After the reaction is complete, wash with deionized water until the pH of the filtrate is stable between 6 and 7, and then dry at 105°C for 6 h to obtain the modified zeolite.

[0030] The other components and preparation methods are the same as in Example 1.

[0031] Comparative Example 2 This embodiment is based on Example 1, but differs from Example 1 in that the modified zeolite described in this comparative example is not modified with ammonium oxalate.

[0032] The preparation method of the modified zeolite includes the following steps: M11. Add natural zeolite to a 1 mol / L hydrochloric acid solution and soak at room temperature for 2 hours to remove surface carbonates and soluble metal oxide impurities; wash repeatedly with deionized water until the pH of the filtrate is between 6 and 7, and then dry at 105℃ for 6 hours to obtain pretreated zeolite. M12. Add the pretreated zeolite to a 1 mol / L sodium chloride solution and stir at 80°C for 4 h. After the reaction is complete, wash with deionized water until the pH of the filtrate is stable between 6 and 7, and then dry at 105°C for 6 h to obtain the modified zeolite.

[0033] The other components and preparation methods are the same as in Example 1.

[0034] Comparative Example 3 This embodiment is based on Example 1, but differs from Example 1 in that the zeolite used in this comparative example is not modified with sodium chloride.

[0035] The preparation method of the modified zeolite includes the following steps: M11. Add natural zeolite to a 1 mol / L hydrochloric acid solution and soak at room temperature for 2 hours to remove surface carbonates and soluble metal oxide impurities; wash repeatedly with deionized water until the pH of the filtrate is between 6 and 7, then dry at 105℃ for 6 hours and cool to obtain pretreated zeolite. M12. The pretreated zeolite was added to a 1 mol / L ammonium oxalate solution and stirred at 80°C for 4 h to obtain a zeolite suspension. The suspension was then washed with deionized water until the pH of the filtrate stabilized between 6 and 7. The washed product was dried at 105°C for 6 h and then placed in a muffle furnace and heated to 380°C at 5°C / min. After holding at this temperature for 3 h, the product was naturally cooled to obtain the modified zeolite.

[0036] The other components and preparation methods are the same as in Example 1.

[0037] Comparative Example 4 This embodiment differs from Example 1 in that unmodified zeolite is used instead of modified zeolite in this comparative example. Natural zeolite was repeatedly washed with deionized water until the filtrate was clear to remove surface dust, and then dried at 105°C for 6 hours to obtain unmodified zeolite.

[0038] The other components and preparation methods are the same as in Example 1.

[0039] Comparative Example 5 This embodiment differs from Embodiment 1 in that the modified coconut shell biochar described in this comparative example is not modified with nitric acid.

[0040] The method for preparing the modified coconut shell biochar includes the following steps: M21. The coconut shell biochar was repeatedly washed with deionized water to remove surface dust, and then dried at 105℃ for 6 hours to obtain pretreated coconut shell biochar. M22. Add the pretreated coconut shell biochar to a 0.2 mol / L zirconium oxychloride solution and stir and soak at room temperature for 6 h to obtain coconut shell biochar suspension A; M23. While stirring, sodium hydroxide solution was added dropwise to coconut shell biochar suspension A to adjust the pH of the system to 8-9; stirring was continued for 1 hour to allow complete precipitation, the mixture was filtered and separated, and washed three times with deionized water to obtain the coconut shell biochar precursor. M24. The coconut shell biochar precursor was dispersed in a 0.5 mol / L phosphoric acid solution, stirred in a 60℃ water bath for 4 h, filtered, washed three times with deionized water, and dried at 105℃ to constant weight to obtain the dried product. M25. The dried product was placed in a 0.5 mol / L phosphoric acid solution, transferred to a hydrothermal reactor, and hydrothermally treated at 150°C for 12 h. After natural cooling, it was filtered, washed three times with deionized water, and dried at 105°C to constant weight to obtain modified coconut shell biochar.

[0041] The other components and preparation methods are the same as in Example 1.

[0042] Comparative Example 6 This embodiment differs from Embodiment 1 in that the modified coconut shell biochar described in this comparative example is modified only with zirconium oxychloride, without the addition of phosphoric acid for reaction, i.e., no zirconium phosphate is generated.

[0043] The method for preparing the modified coconut shell biochar includes the following steps: M21. Coconut shell biochar was repeatedly washed with deionized water to remove surface dust, and then dried at 105℃ for 6 hours to obtain pretreated coconut shell biochar. The pretreated coconut shell biochar was dispersed in a 1 mol / L nitric acid solution and stirred at 60℃ for 4 hours. Then it was filtered, washed with deionized water until the pH of the filtrate was between 6 and 7, and dried at 105℃ to constant weight to obtain oxidized pretreated coconut shell biochar. M22. Add the pre-oxidized coconut shell biochar to a 0.2 mol / L zirconium oxychloride solution and stir and soak at room temperature for 6 h to obtain coconut shell biochar suspension A; M23. While stirring, sodium hydroxide solution was added dropwise to coconut shell biochar suspension A to adjust the pH of the system to 8-9; stirring was continued for 1 hour to allow complete precipitation, the mixture was filtered and separated, and washed three times with deionized water to obtain the coconut shell biochar precursor. M24. The above coconut shell biochar precursor was dried at 105℃ to constant weight, and then heated to 340℃ at a heating rate of 5℃ / min under a nitrogen atmosphere and held at that temperature for 2 hours. It was then naturally cooled to room temperature, washed three times with deionized water, and dried at 105℃ to constant weight to obtain modified coconut shell biochar.

[0044] The other components and preparation methods are the same as in Example 1.

[0045] Comparative Example 7 This embodiment differs from Example 1 in that unmodified coconut shell biochar is used instead of modified coconut shell biochar in this comparative example. The coconut shell biochar is repeatedly washed with deionized water to remove surface dust, and then dried at 105°C for 6 hours to obtain unmodified coconut shell biochar.

[0046] The other components and preparation methods are the same as in Example 1.

[0047] Comparative Example 8 This embodiment differs from Embodiment 1 in that unmodified coconut shell biochar and unmodified zeolite are used instead of modified zeolite and modified coconut shell biochar in this comparative example.

[0048] The other components and preparation methods are the same as in Example 1.

[0049] Comparative Example 9 This embodiment is based on Embodiment 1, but differs from Embodiment 1 in that no modified zeolite is added in this comparative example.

[0050] The other components and preparation methods are the same as in Example 1.

[0051] Comparative Example 10 This embodiment differs from Embodiment 1 in that no modified coconut shell biochar is added in this comparative example.

[0052] The other components and preparation methods are the same as in Example 1.

[0053] Comparative Example 11 This embodiment differs from Example 1 in that 3-aminopropyltriethoxysilane is not added; that is, the modified zeolite and modified coconut shell biochar are directly physically mixed.

[0054] The other components and preparation methods are the same as in Example 1.

[0055] Experimental verification: 1. Initial Adsorption Performance Test Nessler's reagent spectrophotometry (HJ 535-2009) was used. 1.000 g (±0.002 g) of the adsorbent material from Examples 1-3 and Comparative Examples 1-11 was accurately weighed and placed in a 250 mL Erlenmeyer flask; 100 mL of 50.0 mg / L ammonium chloride solution (pH = 7.0 ± 0.1, adjusted with 0.1 mol / L hydrochloric acid or sodium hydroxide) was added; the solution was shaken at 150 rpm for 4 h in a constant temperature shaker at 25 °C; after standing, the supernatant was collected, filtered through a 0.45 μm filter membrane, and an appropriate amount of the supernatant was diluted with deionized water to a final volume to achieve an ammonia nitrogen concentration in the range of 0.1–1.5 mg / L. The ammonia nitrogen concentration was determined after color development according to the procedure specified in HJ 535-2009; the concentration was multiplied by the corresponding dilution factor during calculation; three parallel samples were prepared for each adsorbent material.

[0056] Removal rate ( ): Percentage of ammonia nitrogen removed from the solution; % in, =50.0 mg / L; The concentration after adsorption is given.

[0057] Table 1. Initial ammonia nitrogen removal rate test results: 2. High-temperature regeneration cycle test After conducting the first adsorption test (same as the initial adsorption performance test) on Examples 1-3, Comparative Examples 8, and Comparative Examples 11, the removal rate was measured. The adsorbent material was gently rinsed three times with deionized water (to remove surface residue), dried at 105℃, calcined at 250℃ for 2 hours in a nitrogen atmosphere (heating rate 5℃ / min), and then allowed to cool naturally. Adsorption tests were then performed again under the same conditions to obtain… Repeat 5 times and calculate the regeneration efficiency each time. ;in This refers to the initial adsorption removal rate. The removal rate is the value after the nth regeneration.

[0058] Table 2. Test results of regeneration efficiency during high-temperature (250℃) regeneration cycle: Combining Tables 1 and 2, it can be seen that the initial ammonia nitrogen removal rates of Examples 1-3 are higher than those of the comparative examples, proving the synergistic effect of the coupling between modified zeolite and modified coconut shell carbon, and that the silane coupling agent interfacial bonding layer, zirconium phosphate, and each modification step are all indispensable. After five high-temperature regenerations at 250℃, the regeneration efficiency of Examples 1-3 remained high, while the regeneration efficiency of Comparative Examples 8 and 11 decreased significantly, with Comparative Example 8 showing a more severe decrease; this proves that the modification treatment and the silane coupling agent interfacial bonding layer together ensure the high-temperature cycling stability of the material, and neither can be omitted.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A coupled adsorption material containing zeolite and biochar, characterized in that, The coupling adsorption material is composed of a modified zeolite, a modified coconut shell biochar, and a silane coupling agent interfacial bonding layer. The modified zeolite is prepared by modification with hydrochloric acid, ammonium oxalate and sodium chloride; the modified coconut shell biochar is prepared by oxidation with nitric acid, modification with zirconium oxychloride and phosphoric acid; the silane coupling agent interfacial bonding layer is formed by hydrolyzing 3-aminopropyltriethoxysilane and loading it onto the surface of the modified zeolite, and then interacting and bonding with zirconium phosphate on the surface of the modified coconut shell biochar, thereby forming a stable interfacial bonding layer between the modified zeolite and the modified coconut shell biochar.

2. The coupled adsorption material containing zeolite and biochar according to claim 1, characterized in that, The preparation method of the modified zeolite includes the following steps: M11. Soak natural zeolite in a 1 mol / L hydrochloric acid solution; wash with deionized water, then dry and cool to obtain pretreated zeolite; M12. Add the pretreated zeolite to a 1 mol / L ammonium oxalate solution, stir to react, and obtain a zeolite suspension; then wash with deionized water; dry the washed product, heat to react, and then cool naturally to obtain activated zeolite; M13. Add the activated zeolite to a 1 mol / L sodium chloride solution and stir to react. After the reaction is complete, wash with deionized water and then dry to obtain the modified zeolite.

3. The coupled adsorption material containing zeolite and biochar according to claim 2, characterized in that, The particle size of the natural zeolite is 0.5-1 mm; the solid-liquid ratio of the natural zeolite to 1 mol / L hydrochloric acid solution is 1:5; the solid-liquid ratio of the pretreated zeolite to 1 mol / L ammonium oxalate solution is 1:7; the solid-liquid ratio of the activated zeolite to 1 mol / L sodium chloride solution is 1:7; the unit of the solid-liquid ratio is g / mL.

4. The coupled adsorption material containing zeolite and biochar according to claim 1, characterized in that, The method for preparing the modified coconut shell biochar includes the following steps: M21. Wash the coconut shell biochar with deionized water and then dry it to obtain pretreated coconut shell biochar; disperse the pretreated coconut shell biochar in a 1 mol / L nitric acid solution and stir; then filter, wash with deionized water, and dry to obtain oxidized pretreated coconut shell biochar. M22. Add the pre-treated coconut shell biochar to a 0.2 mol / L zirconium oxychloride solution and stir to obtain coconut shell biochar suspension A; M23. While stirring, sodium hydroxide solution was added dropwise to coconut shell biochar suspension A to adjust the pH of the system; stirring was continued, the mixture was filtered and separated, and then washed with deionized water to obtain the coconut shell biochar precursor. M24. The coconut shell biochar precursor was dispersed in a 0.5 mol / L phosphoric acid solution, stirred and reacted, filtered, washed with deionized water, and dried to obtain the dried product. M25. The dried product was placed in a 0.5 mol / L phosphoric acid solution, hydrothermally treated, naturally cooled, filtered, washed with deionized water, and dried to obtain modified coconut shell biochar.

5. The coupled adsorption material containing zeolite and biochar according to claim 4, characterized in that, The coconut shell biochar has a mesh size of 60-80 mesh; the solid-liquid ratio of the pretreated coconut shell biochar to 1 mol / L nitric acid solution is 1:20; the solid-liquid ratio of the oxidized pretreated coconut shell biochar to 0.2 mol / L zirconium oxychloride solution is 1:20; the solid-liquid ratio of the coconut shell biochar precursor to 0.5 mol / L phosphoric acid solution is 1:20; the unit of the solid-liquid ratio is g / mL.

6. A method for preparing a coupled adsorption material containing zeolite and biochar, used to prepare the coupled adsorption material as described in any one of claims 1 to 5, characterized in that, The method includes the following steps: M1. Add 3-aminopropyltriethoxysilane to a mixed solution of ethanol and water, adjust the pH with glacial acetic acid, and hydrolyze to obtain a 3-aminopropyltriethoxysilane hydrolysate; M2. The modified zeolite was added to the hydrolysate of 3-aminopropyltriethoxysilane, refluxed, filtered, washed with anhydrous ethanol, and dried to obtain silanized modified zeolite. M3. Silanized modified zeolite and modified coconut shell biochar were dispersed in a mixed solution of ethanol and water, stirred and reacted, and then heat-treated; naturally cooled, washed with deionized water, and dried to obtain a coupled adsorption material containing zeolite and biochar.

7. The method for preparing a coupled adsorption material containing zeolite and biochar according to claim 6, characterized in that, The amount of 3-aminopropyltriethoxysilane used is 3% of the mass of the modified zeolite; the solid-liquid ratio of the total mass of the silanized modified zeolite and the modified coconut shell biochar to the ethanol and water mixed solution is 1:15, and the unit of the solid-liquid ratio is g / mL; the mass ratio of the modified zeolite to the modified coconut shell biochar is 3:1 to 5:

1.

8. The application of the coupled adsorption material containing zeolite and biochar according to any one of claims 1 to 5 or the coupled adsorption material containing zeolite and biochar prepared by the preparation method according to any one of claims 6 to 7 in the high-temperature thermal regeneration cycle treatment of ammonia nitrogen wastewater.

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