Method for deeply treating landfill leachate by utilizing catalytic ozonation
By preparing a highly active and stable ozone oxidation catalyst, the problem of poor catalyst activity and stability was solved, enabling deep treatment and compliant discharge of landfill leachate, and reducing treatment costs.
Patent Information
- Application Number
- CN202511290848.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-10
- Publication Date
- 2026-01-23
AI Technical Summary
Existing ozone catalytic oxidation methods for treating landfill leachate suffer from poor catalyst activity and stability, resulting in high treatment costs, poor efficacy, difficulty in achieving emission standards, and risks of catalyst loss and secondary pollution.
An ozone oxidation catalyst was prepared by impregnation and calcination using iron salts, aluminum salts, manganese salts, cerium salts, scandium salts, and vanadium salts as raw materials and activated carbon as a carrier. The calcination temperature was 800℃~1200℃. Metal ions were loaded onto the surface and pore structure of the activated carbon to form highly reactive active oxide species.
It improves the catalytic activity and stability of the catalyst, enabling the rapid formation of highly reactive active oxide species, effectively degrading organic matter in landfill leachate, achieving effluent quality that meets the "Standards for Pollution Control of Municipal Solid Waste Landfill", reducing treatment costs, and making it suitable for large-scale treatment.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of environmental engineering, and particularly relates to a method for deep treatment of landfill leachate by using ozone catalytic oxidation. BACKGROUND
[0002] Landfill leachate is a kind of organic wastewater derived from a landfill site, which has the characteristics of complex composition, difficult degradation, high concentration and the like, and is difficult to treat and has great harm to the environment. Therefore, there is an urgent need to obtain a method for treating landfill leachate.
[0003] As a wastewater deep treatment process, the ozone advanced oxidation method has the advantages of simple operation, cleanliness, no sludge production and the like, and has been widely used in the treatment of landfill leachate. However, the method for treating landfill leachate by using ozone oxidation in the prior art still has the following defects: (1) the active components are single, or the synergistic effect of the active components is poor, it is difficult to improve the catalytic activity of the catalyst, it is difficult to quickly form more active oxidation species with high reactivity in the ozone catalytic system, and then the degradation and mineralization effect of pollutants is poor, so that the concentration of COD and ammonia nitrogen in the system is difficult to reach the discharge standard; (2) the active components in the catalyst are easy to be lost, which easily leads to catalyst failure, or the recycling performance is poor. On the one hand, in order to increase the catalytic activity of the catalyst, the active components are usually directly added to the system, but the active components are difficult to recover, which easily leads to a large amount of catalyst loss, not only increases the treatment cost, but also easily causes secondary pollution risk, and cannot be widely used on a large scale, on the other hand, by loading the active components on the carrier, the recovery of the catalyst can be realized, but the loading stability of the active components on the carrier is still poor, which leads to the easy falling off of the active components from the carrier, and the poor dispersibility of the active components on the carrier, which also makes the exposure site of the active components on the surface of the catalyst very small, and is not conducive to improving the catalytic efficiency of the catalyst.
[0004] For example, researchers in the prior art have proposed a method for deep treatment of high-concentration refractory organic wastewater, which can realize the deep treatment of high-concentration refractory organic wastewater by contacting the flocculation-treated high-concentration refractory organic wastewater with a composite heterogeneous ozone catalyst oxidation tank, but it still has the defects that the active components are easy to be lost and the catalyst is easy to be invalid, which leads to high treatment cost, and because the catalyst is easy to enter the water body, the secondary pollution risk is serious, and it cannot be widely used on a large scale.
[0005] For example, researchers in the prior art have proposed a method for treating landfill leachate by heterogeneous catalytic ozonation, in which a copper active component and potassium cocatalyst are supported on an activated carbon carrier to prepare a catalytic ozone catalyst. However, the method is difficult to achieve deep treatment of the landfill leachate, in which the landfill leachate is continuously subjected to catalytic ozonation for 120 minutes under the action of the catalyst, and the COD value of the effluent is 1054 mg / L, which cannot achieve standard discharge. The reason may be that the active component is single, and it is difficult to improve the catalytic activity of the catalyst.
[0006] In addition, researchers in the prior art have proposed a supported ozone catalyst. Although the type of active component is increased, the supported ozone catalyst can be used to treat reverse osmosis concentrated water, but the COD of the effluent is still as high as 1121 mg / L, which cannot achieve standard discharge. The reason may be that (a) the metal oxide is used as the active component, the catalytic activity is poor, and it is difficult to effectively improve the catalytic activity of the catalyst, resulting in poor degradation effect of pollutants; (b) the use of a binder easily wraps the metal oxide inside the catalyst, resulting in fewer catalytic active sites on the surface of the catalyst, low utilization rate of ozone, and difficulty in achieving efficient degradation of pollutants; (c) the catalyst is easy to collapse and deactivate, and is difficult to reuse.
[0007] Therefore, obtaining an ozone catalyst with high catalytic activity and good stability promotes the deep treatment of landfill leachate by ozone oxidation. SUMMARY
[0008] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a method for deep treatment of landfill leachate by ozone catalytic oxidation, which is simple in process, easy to operate, low in cost, high in treatment efficiency and good in removal effect.
[0009] To solve the above technical problems, the following technical solutions are adopted.
[0010] A method for deep treatment of landfill leachate by ozone catalytic oxidation, which utilizes ozone oxidation catalyst and ozone to catalytically oxidize the landfill leachate. The ozone oxidation catalyst is prepared by using iron salt, aluminum salt, manganese salt, cerium salt, scandium salt, vanadium salt as raw materials and activated carbon as carrier, and then impregnating and calcining.
[0011] The method is further improved, and the calcination temperature is 900-1100 DEG C.
[0012] The method is further improved, and the heating rate during the calcination process is 10 DEG C / min, and the calcination time is 12 h.
[0013] The method is further improved, and the mass ratio of the iron salt, the aluminum salt, the manganese salt, the cerium salt, the scandium salt, and the vanadium salt is 39.98:8.93:4.86:2.35:0.66:0.67.
[0014] The method is further improved, and the preparation method of the ozone oxidation catalyst comprises the following steps: S1, preparing a mixed solution of iron salt, aluminum salt, manganese salt, cerium salt, scandium salt, and vanadium salt; S2, mixing the mixed solution obtained in step S1 with activated carbon, impregnating, and drying to obtain a precursor mixture; S3, calcining the precursor mixture obtained in step S2 to obtain an ozone oxidation catalyst.
[0015] The method is further improved, and the preparation method of the mixed solution in step S1 comprises the following steps: S11, mixing the iron salt, the aluminum salt, the manganese salt, and the vanadium salt with water respectively to obtain an iron salt solution, an aluminum salt solution, a manganese salt solution, and a vanadium salt solution; and mixing the cerium salt and the scandium salt with water to obtain a cerium-scandium solution; S12, adding the aluminum salt solution, the manganese salt solution, the vanadium salt solution, and the cerium-scandium solution to the iron salt solution and stirring to obtain a mixed solution.
[0016] The method is further improved, and in step S11, the ratio of the iron salt to water in the iron salt solution is 0.3998 kg:1 L, the ratio of the aluminum salt to water in the aluminum salt solution is 0.893 kg:3 L, the ratio of the manganese salt to water in the manganese salt solution is 0.243 kg:1 L, the ratio of the vanadium salt to water in the vanadium salt solution is 0.134 kg:1 L, and the ratio of the cerium salt, the scandium salt, and water in the cerium-scandium solution is 0.235 kg:0.066 kg:1 L; the iron salt is a sulfate salt, the aluminum salt is aluminum sulfate, the manganese salt is manganese sulfate, the vanadium salt is ammonium metavanadate, the cerium salt is cerium chloride, and the scandium salt is scandium chloride. In step S12, the stirring time is 30 min.
[0017] The method is further improved, and in step S2, the ratio of the activated carbon to the mixed solution is 80 kg:165 L, the impregnation time is 48 h, the drying temperature is 90°C, and the drying time is 8 h.
[0018] The method is further improved, and the garbage leachate is treated by catalytic oxidation of ozone oxidation catalyst and ozone, and the method comprises the following steps: mixing the ozone oxidation catalyst with the garbage leachate, and treating the garbage leachate by catalytic oxidation of ozone; the mass ratio of the ozone oxidation catalyst to COD in the garbage leachate is 135:1, and the mass ratio of the ozone to COD in the garbage leachate is 5:1.
[0019] The method is further improved, and the pH of the garbage leachate is 7-9; the catalytic oxidation treatment time is 120 min, and the catalytic oxidation treatment temperature is 15-50 DEG C.
[0020] Compared with the prior art, the method has the following advantages: In view of the problems of poor catalytic activity and stability of the catalyst in the prior art ozone catalytic oxidation method, and the problems of high treatment cost, poor treatment effect and difficulty in achieving standard discharge, the application creatively provides a method for treating garbage leachate by ozone catalytic oxidation, and the garbage leachate is treated by catalytic oxidation of ozone oxidation catalyst and ozone, wherein the ozone oxidation catalyst is prepared by using iron salt, aluminum salt, manganese salt, cerium salt, scandium salt and vanadium salt as raw materials, and active carbon as a carrier, and then dipping and calcining, and the calcination temperature is 800-1200 DEG C. In the application, the iron ion, aluminum ion, manganese ion, cerium ion, scandium ion and vanadium ion are uniformly loaded on the surface and pore structure of the active carbon by dipping, and then the active carbon is calcined at 800-1200 DEG C, so that the ozone catalyst with high catalytic activity and good stability is obtained. Compared with the conventional catalyst, the ozone oxidation catalyst used in the application has more catalytic active sites, higher catalytic activity and better stability, so that more active oxidation species with high reactivity can be quickly formed in the system when the ozone oxidation catalyst is used to catalyze ozone, and then the active oxidation species can be used to efficiently degrade the organic matter in the garbage leachate, so that the COD in the garbage leachate is effectively removed, and the effluent quality meets the standard of 'Standard for Pollution Control on Solid Waste Landfill' (GB 16889-2008), and the deep treatment of the garbage leachate is finally completed. The method for treating garbage leachate by ozone catalytic oxidation in the application uses the ozone oxidation catalyst with excellent performance to activate ozone to construct a degradation system, so that the garbage leachate can be discharged in accordance with the standard, the treatment cost can be effectively reduced, and the method has the advantages of simple process, convenient operation, low cost, high treatment efficiency, good removal effect and the like, and is suitable for large-scale treatment of garbage leachate. DETAILED DESCRIPTION
[0021] The application will be further described in connection with specific preferred embodiments, but the scope of the application is not limited thereby. The materials and instruments used in the following examples are commercially available.
[0022] Example 1 A method for deep treatment of landfill leachate by catalytic oxidation of ozone according to the application, specifically, using ozone oxidation catalyst and ozone to catalytically oxidize landfill leachate, comprising the following steps: (1) Preparation of ozone oxidation catalyst (1.1) 39.98 kg of iron sulfate (Fe2(SO4)3) is weighed and dissolved in 100 L of deionized water to prepare an iron sulfate solution; 8.93 kg of aluminum sulfate (Al2(SO4)3) is weighed and dissolved in 30 L of deionized water to prepare an aluminum sulfate solution; 4.86 kg of manganese sulfate (MnSO4) is weighed and dissolved in 20 L of deionized water to prepare a manganese sulfate solution; 2.35 kg of cerium chloride (CeCl3) and 0.66 kg of scandium chloride (ScCl3) are weighed and dissolved in 10 L of deionized water to prepare a mixed solution of cerium chloride and scandium chloride; 0.67 kg of ammonium metavanadate (NH4VO3) is weighed and dissolved in 5 L of deionized water by heating and stirring to prepare an ammonium metavanadate solution; the above aluminum sulfate solution, manganese sulfate solution, mixed solution of cerium chloride and scandium chloride, and ammonium metavanadate solution are added to the iron sulfate solution, and stirred for 30 min to ensure that each component is fully dissolved, obtaining 165 L of impregnation solution.
[0023] (1.2) 80 kg of coal-based activated carbon is added to the impregnation solution obtained in step (1.1) and soaked for 48 h. During the soaking process, the adsorption of activated carbon is used to uniformly load iron ions, aluminum ions, manganese ions, cerium ions, scandium ions, and vanadium ions onto the surface and pore structure of activated carbon. After the soaking is completed, the activated carbon is placed in a tray and dried in a constant temperature drying box at 90°C for 8 h to obtain activated carbon loaded with metal ions.
[0024] (1.3) The activated carbon loaded with metal ions obtained in step (1.2) is placed in a muffle furnace and heated at a rate of 10°C / min to 1000°C, and calcined at 1000°C for 12 h. During the calcination process, the ozone oxidation catalyst is obtained.
[0025] (2) Treatment of landfill leachate The leachate is collected, and the ozone oxidation catalyst obtained in step (1.3) is added into the leachate according to a mass ratio of the ozone oxidation catalyst to COD in the leachate of 135:1. The ozone is continuously introduced for 120 min according to a mass ratio of the ozone to COD in the leachate of 5.0:1 at 25 DEG C. During the catalytic oxidation treatment, more active oxidative species (such as singlet oxygen) can be quickly formed in the system, and then the active oxidative species can be used to efficiently degrade the organic matters in the leachate, so that the COD in the leachate is effectively removed, and the deep treatment of the leachate is finally realized. The collected leachate is the effluent of a leachate biochemical treatment system of a landfill site, the COD in the leachate is 873.67 mg / L, and the pH value is 8.67.
[0026] The effluent after the catalytic oxidation reaction is detected, and the COD in the effluent is 80.53 mg / L. It can be seen that the water quality of the effluent reaches the standard in Table 2 of the Standard for Pollution Control on the Landfill Site of Domestic Waste (GB 16889-2008).
[0027] Example 2 A method for deep treatment of leachate by ozone catalytic oxidation according to the present application is basically the same as that in Example 1, and the difference is only that the content of COD in the leachate is different, that is, in step (2), the COD in the leachate is 1913.51 mg / L, and the pH value is 8.61.
[0028] The effluent after the catalytic oxidation reaction is detected, and the COD in the effluent is 88.17 mg / L. It can be seen that the water quality of the effluent reaches the standard in Table 2 of the Standard for Pollution Control on the Landfill Site of Domestic Waste (GB 16889-2008).
[0029] Example 3 A method for deep treatment of leachate by ozone catalytic oxidation according to the present application is basically the same as that in Example 1, and the difference is only that the content of COD in the leachate is different, that is, in step (2), the COD in the leachate is 2867.33 mg / L, and the pH value is 8.59.
[0030] The effluent after the catalytic oxidation reaction is detected, and the COD in the effluent is 91.63 mg / L. It can be seen that the water quality of the effluent reaches the standard in Table 2 of the Standard for Pollution Control on the Landfill Site of Domestic Waste (GB 16889-2008).
[0031] Example 4 A method for deep treatment of landfill leachate by catalytic ozonation of the application is basically the same as that in Example 1, the difference is only that the COD content in the treated landfill leachate is different, that is, in step (2), the COD in the landfill leachate is 4123.91 mg / L, and the pH value is 8.36.
[0032] The effluent after catalytic oxidation reaction was detected, and the COD in the effluent was 96.12 mg / L, so the water quality of the effluent reached the standard in Table 2 of "Landfill Pollution Control Standard" (GB 16889-2008).
[0033] Example 5: A method for deep treatment of landfill leachate by catalytic ozonation of the application is basically the same as that in Example 1, the difference is only that the preparation method of the ozone oxidation catalyst is different, that is, in step (1.3), the calcination temperature is 700℃, 800℃, 900℃, 1000℃, 1100℃, 1200℃ and 1300℃, respectively.
[0034] The treated liquid after catalytic oxidation reaction was detected, and the results are shown in Table 1.
[0035] Table 1 Influence of different ozone oxidation catalysts on treatment effect of landfill leachate
[0036] As shown in Table 1, when the calcination temperature is 800℃-1200℃, the prepared ozone oxidation catalyst can effectively remove COD in the landfill leachate, and can make the COD content in the landfill leachate meet the relevant emission standards; when the calcination temperature is less than 800℃ or greater than 1200℃, the COD in the landfill leachate cannot be effectively removed, and the relevant emission standards cannot be met, which also shows that in the present application, by optimizing the calcination temperature, ozone catalyst with high catalytic activity can be obtained.
[0037] Example 6: A method for deep treatment of landfill leachate by catalytic ozonation of the application, specifically, the landfill leachate is treated by cyclic oxidation using ozone oxidation catalyst, comprising the following steps: (1) Collect 2000 mL of landfill leachate, according to the mass ratio of ozone oxidation catalyst to COD in landfill leachate is 135:1, add the ozone oxidation catalyst prepared in Example 1, according to the mass ratio of ozone to COD in landfill leachate is 5.0:1, continuously pass in ozone for 120 min, and carry out catalytic oxidation treatment at 28℃.
[0038] In the step, the collected landfill leachate is the effluent of the landfill leachate biochemical treatment system of the landfill, the COD of the landfill leachate is 873.67 mg / L, and the pH value of the landfill leachate is 8.67.
[0039] (2) The ozone oxidation catalyst is taken out, and the step (1) is repeated to perform a cycle experiment, and the continuous treatment of the landfill leachate is completed for 9 times.
[0040] The treatment liquid after each catalytic oxidation reaction is detected, and the results are shown in Table 2.
[0041] Table 2 Influence of the ozone oxidation catalyst on the treatment effect of the landfill leachate under different cycle times
[0042] As shown in Table 2, the ozone oxidation catalyst used in the present application still has very obvious COD removal effect on the landfill leachate after being used for 9 times, the COD content in the effluent is reduced to 75.69 mg / L-80.23 mg / L, the COD concentration in the effluent can reach the standard in Table 2 of the “Domestic Waste Landfill Pollution Control Standard” (GB 16889-2008), and the COD removal rate reaches 90.82%-91.34%. In addition, the loss of the ozone oxidation catalyst is less than 5% during the treatment process. It can be seen that the ozone oxidation catalyst used in the present application has excellent catalytic activity and stability, can be reused, and has low consumption, which can greatly save the cost of reagents. This also shows that: in the present application, the ozone catalyst with high catalytic activity and good stability can be obtained by optimizing the calcination temperature.
[0043] According to the above results, the method for deep treatment of landfill leachate by using ozone catalytic oxidation in the present application can prepare the ozone catalyst with high catalytic activity and good stability by optimizing the calcination temperature, when the ozone catalyst is used for catalyzing ozone, more active oxidative species with high reactivity can be quickly formed in the system, and then the active oxidative species can be used to efficiently degrade the organic matter in the landfill leachate. Not only can the landfill leachate meet the discharge standard, but also the treatment cost can be effectively reduced. The method has the advantages of simple process, convenient operation, low cost, high treatment efficiency, good removal effect, etc., and can realize the continuous treatment of the landfill leachate.
[0044] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the spirit and technical solutions of the present application, can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solutions of the present application, still belongs to the protection scope of the technical solutions of the present application.
Claims
1. A method for deep treatment of landfill leachate using ozone catalytic oxidation, characterized in that, The method utilizes ozone oxidation catalyst and ozone to catalytically oxidize landfill leachate; the ozone oxidation catalyst is prepared by impregnation and calcination of iron salt, aluminum salt, manganese salt, cerium salt, scandium salt, and vanadium salt as raw materials and activated carbon as a carrier; the calcination temperature is 800℃~1200℃.
2. The method according to claim 1, characterized in that, The roasting temperature is 900℃~1100℃.
3. The method according to claim 2, characterized in that, The heating rate during the roasting process is 10℃ / min; the roasting time is 12h.
4. The method according to claim 3, characterized in that, The mass ratio of the iron salt, aluminum salt, manganese salt, cerium salt, scandium salt, and vanadium salt is 39.98:8.93:4.86:2.35:0.66:0.
67.
5. The method according to claim 4, characterized in that, The preparation method of the ozone oxidation catalyst includes the following steps: S1. Prepare a mixed solution of iron salts, aluminum salts, manganese salts, cerium salts, scandium salts, and vanadium salts; S2. Mix the mixed solution obtained in step S1 with activated carbon, impregnate, and dry to obtain a precursor mixture; S3. The precursor mixture obtained in step S2 is calcined to obtain an ozone oxidation catalyst.
6. The method according to claim 5, characterized in that, In step S1, the method for preparing the mixed solution includes the following steps: S11. Mix iron salt, aluminum salt, manganese salt, and vanadium salt with water to obtain iron salt solution, aluminum salt solution, manganese salt solution, and vanadium salt solution, respectively; mix cerium salt and scandium salt with water to obtain cerium-scandium solution; S12. Add aluminum salt solution, manganese salt solution, vanadium salt solution, and cerium scandium solution to iron salt solution, stir, and obtain a mixed solution.
7. The method according to claim 6, characterized in that, In step S11, the ratio of iron salt to water in the iron salt solution is 0.3998 kg:1 L, the ratio of aluminum salt to water in the aluminum salt solution is 0.893 kg:3 L, the ratio of manganese salt to water in the manganese salt solution is 0.243 kg:1 L, the ratio of vanadium salt to water in the vanadium salt solution is 0.134 kg:1 L, and the ratio of cerium salt, scandium salt, and water in the cerium-scandium solution is 0.235 kg:0.066 kg:1 L. The iron salt is a sulfate, the aluminum salt is aluminum sulfate, the manganese salt is manganese sulfate, the vanadium salt is ammonium metavanadate, the cerium salt is cerium chloride, and the scandium salt is scandium chloride. In step S12, the stirring time is 30 minutes.
8. The method according to claim 5, characterized in that, In step S2, the ratio of activated carbon to mixed solution is 80 kg: 165 L, the impregnation time is 48 h, the drying temperature is 90 °C, and the drying time is 8 h.
9. The method according to any one of claims 1 to 8, characterized in that, Catalytic oxidation treatment of landfill leachate using ozone oxidation catalyst and ozone includes the following steps: mixing ozone oxidation catalyst with landfill leachate, and introducing ozone for catalytic oxidation treatment to complete the deep treatment of landfill leachate; the mass ratio of ozone oxidation catalyst to COD in landfill leachate is 135:1, and the mass ratio of ozone to COD in landfill leachate is 5:
1.
10. The method according to claim 9, characterized in that, The pH of the landfill leachate is 7-9; the catalytic oxidation treatment time is 120 min; and the catalytic oxidation treatment temperature is 15℃-50℃.