Preparation method and application of high-efficiency anti-interference environment-friendly heterogeneous catalyst

Abstract

The application discloses a preparation method and application of an efficient anti-interference environment-friendly heterogeneous catalyst, and the method comprises the following steps: S1, preparing raw biochar BC; S2, treating the raw biochar BC in multiple levels of pores; and S3, preparing the heterogeneous catalyst by using a pyrolysis method. The application can regulate the surface structure of the biochar BC, optimizes iron and nitrogen doping dispersion mixing, significantly improves the raw sludge biochar activation persulfate advanced oxidation technology, and improves the degradation effect of the biochar on groundwater pollutants and the anti-interference property of the biochar on complex components of the groundwater and the applicability of the biochar to pH, so that the application has a good application prospect in groundwater remediation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a preparation method and application of an efficient anti-interference environment-friendly heterogeneous catalyst. BACKGROUND

[0002] Commonly used remediation technologies for organic contaminated groundwater include in-situ thermal treatment technology, multi-phase extraction technology, chemical reduction / oxidation technology, bioremediation technology, extraction-treatment technology, permeable reactive barrier technology, etc. In-situ chemical oxidation technology (ISCO) has become one of the most commonly used technologies for soil and groundwater remediation due to its fast remediation speed and low cost. The advanced oxidation technology based on persulfate, including peroxymonosulfate (PMS) and peroxysulfate (PDS), has attracted widespread attention from scholars due to its diverse activation methods, wide pH adaptation range, and convenient transportation and storage. Persulfate can be decomposed to produce more oxidizing sulfate radicals (SO4·, E 0 = 2.5-3.1 ev) after being activated by heat, alkali, transition metals, ultraviolet light, ultrasonic waves, etc. SO4· reacts with organic molecules through hydrogen absorption, double bond addition, and electron transfer.

[0003] The traditional persulfate-based advanced oxidation technology still has many problems in the remediation of groundwater porous media: first, the activated persulfate system has strong reactivity with the underground porous media, which is prone to oxidation and chelation with the porous media, resulting in excessive consumption of the activator and persulfate, short transportation distance of the reagents in the groundwater porous media, and difficult to guarantee the removal effect of pollutants in actual field remediation, as well as resource waste and environmental pollution. Second, the existing persulfate activation methods can easily lead to rapid decomposition of persulfate and rapid generation of free radicals, resulting in free radical-free radical reactions rather than free radical-pollutant reactions, and the mass transfer process between the oxidant and the pollutant becomes the rate-limiting step, which leads to poor oxidation and degradation effect of activated persulfate on pollutants. The non-selectivity and complexity of SO4· oxidation reaction limit its application in the remediation of organic contaminated groundwater.

[0004] Carbon materials have the characteristics of environmental friendliness, abundant earth resources, and easy-to-control structural properties. In recent years, biochar-based catalysts produced by pyrolysis of waste biomass have attracted widespread attention. Biochar materials have large specific surface area, rich surface functional groups, and easy-to-control structure, and are widely used in catalysis, adsorption, and other fields, with good sustainable development potential and application prospects. Biochar materials can not only be used as adsorbents or catalyst supports, but also as catalysts themselves. Due to its complex surface properties and structural characteristics, biochar materials often involve free radical oxidation and non-free radical oxidation pathways when in contact with persulfate. The former produces ·OH, SO4· and O2·, etc. through single electron transfer and chain reaction in the activation process of persulfate; the latter relies on O2, electron transfer and surface-bound active oxygen. Compared with the free radical method, the non-free radical method has lower redox capacity, better selectivity for organic matter, and stronger resistance to environmental background and complex water matrix. Biochar prepared by high-temperature pyrolysis of sludge has good stability and low biological toxicity, and can be used to catalyze the oxidation and degradation of dyes, estrogens and sulfonamides and other organic pollutants by persulfate. 1 O2, electron transfer and surface-bound active oxygen. Compared with the free radical method, the non-free radical method has lower redox capacity, better selectivity for organic matter, and stronger resistance to environmental background and complex water matrix. Biochar prepared by high-temperature pyrolysis of sludge has good stability and low biological toxicity, and can be used to catalyze the oxidation and degradation of dyes, estrogens and sulfonamides and other organic pollutants by persulfate.

[0005] However, the original carbon in sludge-based biochar catalysts generally has low catalytic activity. Heteroatom (N, B, S, etc.) doping, especially N doping, has been proven to be an important method to adjust the electronic distribution of sp 2 hybrid carbon matrix, break the inert carbon layer, and thus improve the electron transfer capacity. However, the improvement of catalytic activity of biochar by heteroatom doping is limited, and it is also limited in practical application due to poor stability. In order to further improve the high catalytic activity of sludge-based biochar catalysts, transition metal (Fe, Co, etc.) doping can be carried out, which has been proven to be an effective method to improve the activation performance of persulfate. Iron ions (Fe 2+ ) are often used as activators for persulfate due to their low cost and high efficiency. However, the leaching of Fe 2+ and the slow conversion of Fe 3+ / Fe 2+ redox cycle limit its stability and scalability for PS oxidation. Iron-nitrogen co-doped carbon catalysts (Fe-N-C) have good catalytic activity, which can make up for the inherent defects of single element doping. The addition of iron can greatly improve the catalytic performance, and the addition of nitrogen can help to disperse iron and effectively prevent the leaching of iron. The reported Fe / N co-doped biochar materials use precursors such as wood chips, algae, coffee grounds, etc., and there are few reports on using sludge as a precursor, and the treatment methods are mostly conventional methods such as hydrothermal method. SUMMARY

[0006] To solve the above problems, the application provides a preparation method of an efficient anti-interference environment-friendly heterogeneous catalyst.

[0007] The technical scheme of the application is as follows: a preparation method of an efficient anti-interference environment-friendly heterogeneous catalyst, comprising the following steps:

[0008] S1, preparing raw biochar BC:

[0009] The sludge is air-dried for 23-25 hours, then ground and crushed, and passed through a 100-mesh sieve to obtain sludge powder, which is placed in a tube furnace under a nitrogen protective atmosphere, heated to 550-610 DEG C at a heating rate of 10 DEG C / min, and then pyrolyzed for 2 hours, and then cooled to room temperature; the sludge powder is washed with 1 mol / L hydrochloric acid and soaked for 12-13 hours, then washed with deionized water multiple times until the washing liquid is neutral, and then dried, ground and crushed to obtain raw biochar BC, and the raw biochar BC is treated to obtain multi-layered porous carbon.

[0010] S2, preparing a heterogeneous catalyst by a pyrolysis method:

[0011] S2-1, in the ratio of 100 mL:2 mmol:2-12 mmol:5 g, FeCl3.6H2O, urea and multi-layered porous carbon are sequentially added to pure water, the adding method is: first, FeCl3.6H2O and urea are added to pure water and stirred and heated, heated to 50-60 DEG C, then half of the mass of the multi-layered porous carbon is added, a mixed system is obtained, then stirred and dried in a vacuum environment until the volume of the mixed system is 50 mL; the remaining half of the mass of the multi-layered porous carbon is added, stirred, and then freeze-dried until completely dry to obtain a dry powder;

[0012] S2-2, the dry powder obtained in step S2-1 is placed in a tube furnace and pyrolyzed under a nitrogen protective atmosphere, the pyrolysis temperature is 750-850 DEG C, and the pyrolysis is completed by maintaining the temperature for 1 hour, and then cooled to room temperature; then washed with deionized water and ethanol multiple times until the washing liquid is neutral, and finally dried, ground and sieved to obtain a heterogeneous catalyst.

[0013] Description: By using sludge as a raw material, the production cost of raw materials can be reduced, waste can be turned into treasure, efficient utilization of sludge resources in municipal sewage treatment plants can be achieved, chemical substances can be avoided as precursors for preparing carbon-based materials, toxic and harmful reagents can be avoided, batch production can be achieved, and environmental problems can be avoided; N doping can adjust sp 2The electronic distribution of the hybrid carbon matrix breaks the inert carbon layer; the addition of iron can greatly improve the catalytic performance, and the sludge as a precursor can synergistically promote the Fe / N co-doped system to enhance the catalyst performance. The carbon material prepared by the above method is beneficial to groundwater pollution remediation, and can significantly improve the anti-interference ability in dealing with complex components in groundwater during the remediation process compared with other preparation methods. The anti-interference ability prepared by the conventional hydrothermal method is weak, which may be due to the fact that the raw materials are suitable for this treatment method.

[0014] Further, the drying in the vacuum environment in step S2-1 is: using a vacuum dryer to dry under a pressure of 200-300 Pa; the freeze-drying is: drying at-60 to-50℃.

[0015] It is explained that: through the above two drying methods, the connectivity and shape of the multi-level pores can be maintained accordingly; at the same time, the pore size can be made uniform accordingly.

[0016] Further, the freeze-drying method is: using a freeze dryer to first cool at 2-4℃ / min to-30℃, maintain for 5-10 min, then cool at 5-7℃ / min to-60 to-50℃, until completely dry.

[0017] It is explained that: through the above method of controlling freeze-drying, the specific surface area of the multi-level porous carbon can be avoided from being reduced due to too large temperature difference, and the adsorption performance can be reduced.

[0018] Further, in step S2-2, the temperature rising pyrolysis method is: first, the temperature is raised at a rate of 8-10℃ / min from room temperature, when the temperature rises to 105-115℃, the pressure in the tube furnace is increased to 200-300kPa, when the temperature rises to 130-135℃, the pressure is reduced to 160-250kPa, the temperature rising rate is reduced to 5-7℃ / min, when the temperature rises to 300℃, the pressure is kept at 280-300kPa, until the pyrolysis temperature is reached, the pressure is reduced at a rate of 5kPa / min until the pyrolysis is completed.

[0019] It is explained that: through the above pyrolysis method, the temperature contrast with the temperature of the previous step and the corresponding pressure can optimize the multi-level structure of the multi-level porous carbon, increase the specific surface area, and enhance the anti-interference ability.

[0020] Further, the method for treating the multi-level pores in step S1 is:

[0021] S1-1, mix the raw biomass charcoal BC with water accounting for 65% of the mass of the raw biomass charcoal BC, and perform a hydrothermal carbonization reaction at 200-220℃; after the hydrothermal carbonization reaction, cool the reaction product to room temperature, sequentially wash with hydrochloric acid and deionized water until the pH of the deionized water washing effluent is neutral, and dry to obtain a hydrothermal carbon;

[0022] S1-2, spray an activating agent A accounting for 3-4% of the mass of the hydrothermal carbon on the surface of the hydrothermal carbon, place the hydrothermal carbon in a tube furnace, perform heating activation at 400-450℃ under a nitrogen atmosphere for 1-2h, then take out the hydrothermal carbon, sequentially wash with hydrochloric acid and deionized water until the pH of the deionized water washing effluent is neutral, and dry to obtain a primary-pore carbon;

[0023] S1-3, then immerse the primary-pore carbon in an activating agent B, take out the primary-pore carbon after 10-15min, place the primary-pore carbon in a tube furnace, perform heating activation at 460-500℃ under a gas atmosphere for 1-2h, then take out the primary-pore carbon, sequentially wash with hydrochloric acid and deionized water until the pH of the deionized water washing effluent is neutral, and dry to obtain a multi-level porous carbon.

[0024] Description: Through the above method for preparing the multi-level porous carbon, carbon materials under multiple levels of pores can be obtained, and the effect of doping and loading iron and nitrogen of the heterogeneous catalyst can be improved, and the treatment effect is improved, and the multi-level porous carbon has good anti-interference ability in groundwater remediation.

[0025] Further, in the step S1-3, the preparation and adding method of the gas atmosphere is as follows: mix and stir H2O and Fe(OH)3 colloid at a mass ratio of 100:2-5, and atomize the mixture into mixed droplets, and circulate the mixed droplets into the tube furnace with N2 at a mass ratio of 1:15-20:50 to form a constant flow gas atmosphere; wherein the constant flow speed is 1.5-2L / min.

[0026] Description: Through the above adding of the gas atmosphere, the uniformity and the number of levels of the formed pores can be improved, and the H2O and Fe(OH)3 colloid are added in the form of particles together with the gas, which can activate the surface of the carbon material in cooperation with the activating agent, optimize the pore size, and improve the surface activity.

[0027] Further, the activating agent A is obtained by mixing potassium fatty acid and cetylamine at a mass ratio of 1:1, and the activating agent B is potassium laurate.

[0028] Description: Potassium fatty acid has high alkalinity and catalytic activity, which can initiate physical or chemical changes of carbon materials during activation, and realize activation through physicochemical principles; hexadecylamine has good solubility and wetting performance, and the combination of the two can promote each other and enhance the activation effect of carbon materials; potassium laurate has good surface activity, which can reduce the surface tension of the liquid and increase the contact angle between the liquid and the solid, thereby enhancing the activation effect of carbon materials in the gas atmosphere.

[0029] A kind of efficient anti-interference environment-friendly heterogeneous catalyst preparation method, the application of the heterogeneous catalyst prepared by the method, the heterogeneous catalyst is used for groundwater pollution remediation;The groundwater pollution contains SMX pollutants and Ca 2+ , Cl - , NO3 - , SO4 2- , HCO3 - , CO3 2- interference ions.

[0030] Description: The groundwater quality environment is complex, involving various reducing substances, various anions and cations, and organic matter, so the material needs to have anti-interference property, and the heterogeneous catalyst has good repair effect for groundwater remediation.

[0031] The beneficial effects of the present application are:

[0032] (1) The present application uses sludge as raw material, which can reduce the production cost of raw materials, realize the efficient utilization of sludge resources in municipal sewage treatment plant, avoid using chemical substances as precursors to prepare carbon-based materials, and solve the problems of using toxic and harmful reagents, difficult batch production, and environmental protection; N-doping can adjust the electronic distribution of sp 2 hybrid carbon matrix and break the inert carbon layer; the addition of iron can greatly improve the catalytic performance, and sludge as a precursor can synergistically promote the Fe / N co-doped system, enhance the catalyst performance, and the carbon material prepared by the above method is beneficial to groundwater pollution remediation, which can significantly improve the anti-interference property of complex components in groundwater during the repair process compared with other methods.

[0033] (2) The present application sets the molar mass ratio of iron source and nitrogen source to optimize the degradation process, avoid the problems of degradation of organic matter by catalytic persulfate, increase of iron leaching, etc.

[0034] (3) The present application can prepare multi-layered porous carbon, obtain carbon materials under multiple hierarchical pores, and further improve the effect of doping and loading iron and nitrogen of the heterogeneous catalyst, thereby improving the treatment effect and having good anti-interference ability in groundwater remediation. The addition of a gas atmosphere can improve the multi-layer level and uniformity of the formed pores, and the H2O and Fe(OH)3 colloid are added in the form of microparticles together with the gas, which can synergize with the activator to activate the surface of the carbon material, optimize the pore size while improving the surface activity.

[0035] (4) The present application utilizes the high alkalinity and catalytic activity of potassium fatty acid to initiate physical or chemical changes of carbon materials during the activation process, and realizes activation through physical and chemical principles; the good solubility and wetting performance of hexadecylamine can promote each other and enhance the activation effect on carbon materials; the good surface activity of potassium laurate can reduce the surface tension of the liquid and improve the contact angle between the liquid and the solid, thereby enhancing the activation effect of the carbon material in the gas atmosphere. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a material morphology diagram of Example 1 of the present application;

[0037] Figure 2 is a material morphology diagram of Example 1 of the present application;

[0038] Figure 3 is a structure characterization diagram of Example 1 of the present application. DETAILED DESCRIPTION

[0039] The present application will be further described in detail below in combination with specific embodiments to better reflect the advantages of the present application.

[0040] Example 1:

[0041] A preparation method of an efficient anti-interference environmentally friendly heterogeneous catalyst, comprising the following steps:

[0042] S1, preparing raw biochar BC:

[0043] The sludge is air-dried for 24 h, then ground and broken, and passed through a 100-mesh sieve to obtain a sludge powder. The sludge powder is placed in a tube furnace under a nitrogen protective atmosphere, heated to 600℃ at a heating rate of 10℃ / min, and then kept at 600℃ for 2 h to perform pyrolysis, and then cooled to room temperature. The pyrolysis product is washed with 1 mol / L hydrochloric acid and soaked for 12.5 h, then washed with deionized water multiple times until the deionized water washing liquid is neutral, and then dried, ground, and passed through a sieve to obtain the raw-state biochar BC. The raw-state biochar BC is subjected to a multi-level pore treatment to obtain a multi-level porous carbon. The multi-level pore treatment is as follows: the raw-state biochar BC is mixed with water in an amount of 65% of the mass of the raw-state biochar BC, and a hydrothermal carbonization reaction is performed at 210℃. After the hydrothermal carbonization reaction, the reaction product is cooled to room temperature, washed with hydrochloric acid and deionized water until the pH of the deionized water washing liquid is neutral, and then dried to obtain a hydrothermal carbon.

[0044] S2, a heterogeneous catalyst is prepared by a pyrolysis method:

[0045] S2-1, FeCl3·6H2O, urea, and the multi-level porous carbon are sequentially added to pure water in a ratio of 100 mL:2 mmol:10 mmol:5 g. The addition method is as follows: first, FeCl3·6H2O and urea are added to the pure water, stirred, and heated. When the temperature is raised to 55℃, half the mass of the multi-level porous carbon is added to obtain a mixed system. Then, the mixed system is stirred and dried under vacuum until the volume of the mixed system is 50 mL. Then, the remaining half of the mass of the multi-level porous carbon is added, stirred, and freeze-dried until completely dry to obtain a dry powder. The vacuum drying is performed using a vacuum dryer at a pressure of 240 Pa. The freeze-drying is performed as follows: first, the temperature is reduced to -30℃ at a rate of 3℃ / min, and then the temperature is reduced to -55℃ at a rate of 6℃ / min until completely dry.

[0046] S2-2, the dry powder obtained in step S2-1 is placed in a tube furnace and pyrolyzed under a nitrogen protective atmosphere. The pyrolysis temperature is 800℃, and the pyrolysis is performed for 1 h. Then, the pyrolysis product is cooled to room temperature. Then, the pyrolysis product is washed with deionized water and ethanol multiple times until the washing liquid is neutral. Finally, the pyrolysis product is dried, ground, and sieved to obtain the heterogeneous catalyst.

[0047] The temperature increasing and pyrolysis method is as follows: first, the temperature is increased from room temperature at a rate of 9℃ / min. When the temperature is increased to 110℃, the pressure in the tube furnace is increased to 220 kPa. When the temperature is increased to 133℃, the pressure is reduced to 200 kPa, and the temperature increasing rate is reduced to 6℃ / min. When the temperature is increased to 300℃, the pressure is kept at 290 kPa until the pyrolysis temperature is reached. Then, the pressure is reduced at a rate of 5 kPa / min until the pyrolysis is completed.

[0048] Example 2

[0049] The difference between this embodiment and embodiment 1 is that the proportions of raw materials are different, and in step S2-1, FeCl3·6H2O, urea and multi-level porous carbon are sequentially added to pure water in a proportion of 100 mL: 2 mmol: 2 mmol: 5 g.

[0050] Embodiment 3

[0051] The difference between this embodiment and embodiment 1 is that the proportions of raw materials are different, and in step S2-1, FeCl3·6H2O, urea and multi-level porous carbon are sequentially added to pure water in a proportion of 100 mL: 2 mmol: 12 mmol: 5 g.

[0052] Embodiment 4

[0053] The difference between this embodiment and embodiment 1 is that the preparation parameters of the raw biochar BC are different, the sludge is dried for 25 h, and after heating to 550℃, hydrochloric acid washing and soaking for 12 h; in the multi-level pore treatment, the hydrothermal carbonization reaction is carried out at 200℃.

[0054] Embodiment 5

[0055] The difference between this embodiment and embodiment 1 is that the preparation parameters of the raw biochar BC are different, the sludge is dried for 23 h, and after heating to 610℃, hydrochloric acid washing and soaking for 13 h; in the multi-level pore treatment, the hydrothermal carbonization reaction is carried out at 220℃.

[0056] Embodiment 6

[0057] The difference between this embodiment and embodiment 1 is that the preparation parameters in the preparation of the heterogeneous catalyst are different, and in S2-1, after heating to 50℃, half the mass of the multi-level porous carbon is added to obtain a mixed system, and the drying in a vacuum environment is: using a vacuum dryer, drying is carried out at a pressure of 300 Pa; freeze-drying is: using a freeze dryer, first cooling to -30℃ at a rate of 2℃ / min, keeping for 5 min, and then cooling to -50℃ at a rate of 7℃ / min until completely dry.

[0058] Embodiment 7

[0059] The difference between this embodiment and embodiment 1 is that the preparation parameters in the preparation of the heterogeneous catalyst are different, and in S2-1, after heating to 60℃, half the mass of the multi-level porous carbon is added to obtain a mixed system, and the drying in a vacuum environment is: using a vacuum dryer, drying is carried out at a pressure of 200 Pa; freeze-drying is: using a freeze dryer, first cooling to -30℃ at a rate of 4℃ / min, keeping for 10 min, and then cooling to -60℃ at a rate of 5℃ / min until completely dry.

[0060] Embodiment 8

[0061] The difference between this embodiment and embodiment 1 is that the pyrolysis temperature is different, S2-2, the pyrolysis temperature is 750℃.

[0062] Embodiment 9

[0063] The difference between this embodiment and embodiment 1 is that the pyrolysis temperature is different, S2-2, the pyrolysis temperature is 850℃.

[0064] Embodiment 10

[0065] The difference between this embodiment and embodiment 1 is that the temperature rising pyrolysis method is that first, the temperature is raised from room temperature at a rate of 8℃ / min, when the temperature rises to 115℃, the pressure in the tube furnace is increased to 200kPa, when the temperature rises to 135℃, the pressure is reduced to 160kPa, the temperature rising rate is reduced to 5℃ / min, when the temperature rises to 300℃, the pressure is kept at 280kPa, until the pyrolysis temperature is reached, the pressure is reduced at a rate of 5kPa / min until the pyrolysis is completed.

[0066] Embodiment 11

[0067] The difference between this embodiment and embodiment 1 is that the temperature rising pyrolysis method is that first, the temperature is raised from room temperature at a rate of 10℃ / min, when the temperature rises to 105℃, the pressure in the tube furnace is increased to 300kPa, when the temperature rises to 130℃, the pressure is reduced to 250kPa, the temperature rising rate is reduced to 7℃ / min, when the temperature rises to 300℃, the pressure is kept at 300kPa, until the pyrolysis temperature is reached, the pressure is reduced at a rate of 5kPa / min until the pyrolysis is completed.

[0068] Embodiment 12

[0069] The difference between this embodiment and embodiment 1 is that the method of multi-level pore treatment in step S1 is:

[0070] S1-1, mix the raw biochar BC with water accounting for 65% of its mass, and carry out hydrothermal carbonization reaction at 210℃; after the hydrothermal carbonization reaction, cool the reaction product to room temperature, sequentially wash with hydrochloric acid and deionized water until the pH of the deionized water washing effluent is neutral, and dry to obtain hydrothermal carbon;

[0071] S1-2, spray an activating agent A accounting for 3.5% of the mass of the hydrothermal carbon on the surface of the hydrothermal carbon, put it into a tube furnace, heat and activate at 440℃ for 1.5h under a nitrogen atmosphere, then take it out, sequentially wash with hydrochloric acid and deionized water until the pH of the deionized water washing effluent is neutral, and dry to obtain primary pore carbon;

[0072] S1-3, then the primary pore carbon is soaked in the activator B for 13 min, taken out, put into a tube furnace, heated for activation under a gas atmosphere at 480℃ for 1.5 h, then taken out, washed with hydrochloric acid and deionized water in sequence until the pH of the deionized water washing effluent is neutral, and dried to obtain the multi-layered porous carbon;

[0073] The gas atmosphere adopts H2O and nitrogen 1:2 to form a constant flow gas atmosphere; wherein, the constant flow speed is 1.8 L / min;

[0074] The activator A is zinc chloride; and the activator B is potassium hydroxide.

[0075] Example 13

[0076] The difference between this example and Example 12 is that the temperature parameters are different, S1-1, the hydrothermal carbonization reaction is carried out at 200℃; S1-2, the heating activation is carried out at 450℃; and S1-3, the heating activation is carried out at 500℃.

[0077] Example 14

[0078] The difference between this example and Example 12 is that the temperature parameters are different, S1-1, the hydrothermal carbonization reaction is carried out at 220℃; S1-2, the heating activation is carried out at 400℃; and S1-3, the heating activation is carried out at 460℃.

[0079] Example 15

[0080] The difference between this example and Example 12 is that the time parameters are different, S1-2, the heating activation is carried out for 2 h, and S1-3, taken out after 10 min and heated for activation for 1 h.

[0081] Example 16

[0082] The difference between this example and Example 12 is that the time parameters are different, S1-2, the heating activation is carried out for 1 h, and S1-3, taken out after 15 min and heated for activation for 2 h.

[0083] Example 17

[0084] The difference between this example and Example 12 is that, in S1-2, the activator A accounts for 3% of the mass of the hydrothermal carbon on the surface, and in S1-3, the constant flow speed of the gas atmosphere is 2 L / min.

[0085] Example 18

[0086] The difference between this example and Example 12 is that, in S1-2, the activator A accounts for 4% of the mass of the hydrothermal carbon on the surface, and in S1-3, the constant flow speed of the gas atmosphere is 1.5 L / min.

[0087] Example 19

[0088] The difference between this embodiment and embodiment 12 is that the gas atmosphere is different, and the preparation and adding method of the gas atmosphere is that H2O, Fe(OH)3 colloid are mixed and stirred in a mass ratio of 100:4, and are atomized into mixed droplets, and the mixed droplets are circulated into the tube furnace with N2 in a mass ratio of 1:18:50, to form a constant flow gas atmosphere.

[0089] Example 20

[0090] The difference between this embodiment and embodiment 19 is that the component ratio is different, and H2O, Fe(OH)3 colloid are mixed and stirred in a mass ratio of 100:2, and are atomized into mixed droplets, and the mixed droplets are circulated into the tube furnace with N2 in a mass ratio of 1:20:50, to form a constant flow gas atmosphere.

[0091] Example 21

[0092] The difference between this embodiment and embodiment 19 is that the component ratio is different, and H2O, Fe(OH)3 colloid are mixed and stirred in a mass ratio of 100:5, and are atomized into mixed droplets, and the mixed droplets are circulated into the tube furnace with N2 in a mass ratio of 1:15:50, to form a constant flow gas atmosphere.

[0093] Example 22

[0094] The difference between this embodiment and embodiment 12 is that the activator A is a mixture of potassium fatty acid and hexadecylamine in a mass ratio of 1:1; and the activator B is potassium laurate.

[0095] Experimental example

[0096] I. The following table is the heavy metal leaching result of sludge, control groups 1-3 and example 3;

[0097] Table 1 Heavy metal leaching in municipal sewage sludge and sludge biochar

[0098]

[0099]

[0100] Control example 1: raw biochar BC obtained by step S1 in the method of example 1;

[0101] Control example 2: N-SBC is prepared according to the method of example 1, using pure water instead of FeCl3·6H2O;

[0102] Control example 3: Fe-SBC is prepared according to the method of example 1, using pure water instead of urea;

[0103] From Table 1, it can be found that the heavy metal leaching of Example 3 is less, indicating that it has low heavy metal content and low toxicity characteristics;

[0104] II. The heterogeneous catalysts obtained in Examples 1-22 are respectively added to the wastewater containing 20 mg / L of sulfamethoxazole (SMX), and after adsorption equilibrium, 0.4 g / L of oxidant PDS is added to catalytically degrade and mineralize the organic matter;

[0105] SMX removal rate: 0.1 g of the heterogeneous catalyst obtained in Example 1 is added to wastewater containing 20 mg / L of sulfamethoxazole (SMX), and after adsorption equilibrium, 0.4 g / L of oxidant PDS is added to catalytically degrade and mineralize the organic matter; at 120 min, the removal rate of SMX is 99.9%;

[0106] Mineralization rate: 0.6 g of the heterogeneous catalyst obtained in Example 1 and 0.6 g of PDS are added to 20 mg / L of SMX solution, and the mineralization rate (i.e. TOC removal rate) is 98.5%;

[0107] Anti-interference: 10 mM Cl - , NO3 - and 20 mg / L of HA are added to the SMX solution with an initial concentration of 20 mg / L, and the heterogeneous catalysts obtained in Examples 1-22 are used for degradation, and the SMX degradation efficiency is still greater than 80%, indicating that the heterogeneous catalysts have strong anti-interference to common anions and organic matter in groundwater;

[0108] pH applicability: when the initial pH ranges from 3.0 to 9.0, the SMX degradation efficiency after degradation by the heterogeneous catalysts obtained in Examples 1-22 is 94%-97%;

[0109] When pH = 11, the SMX degradation efficiency after degradation by the heterogeneous catalyst obtained in Example 1 is 47.0%, indicating that the heterogeneous catalyst has a wide pH application range;

[0110] 1. Explore the influence of different treatment methods on the performance (anti-interference) of the heterogeneous catalysts;

[0111] Comparative Example 1: The same raw materials as in Example 1 are used, and the heterogeneous catalyst is prepared by a conventional hydrothermal method;

[0112] Comparative Example 2: The biomass material of straw is used as a precursor, and the preparation method of Example 1 is used to prepare the catalyst of Comparative Example 2;

[0113] Examples 1, 12, 19, 22 and Comparative Examples 1-2 are compared, as shown in Table 2;

[0114] Table 2 Experimental results under different treatment methods

[0115]

[0116] From Table 2, it can be seen that,

[0117] Comparing Example 1 with Comparative Example 1, it can be shown that the preparation method of Example 1 is more suitable and safe, and the obtained catalyst has better catalytic and degradation effects and strong anti-ion interference ability;

[0118] Comparing Example 1 with Comparative Example 2, it can be concluded that the sludge-based raw material used in Example 1 has better effect, which may be due to the better doping and loading effect of the sludge, thereby making the anti-interference effect better;

[0119] Comparing Example 1 with Example 12, it can be seen that the catalytic effect of Example 12 is better after multi-level pore treatment, which may be because the surface properties are more superior and the pore is more optimal;

[0120] Comparing Example 12 with Example 22, it can be found that the comprehensive effect of the activator A and the activator B used in Example 22 is obvious, and the activation ability is better;

[0121] Comparing Example 12 with Example 19, it can be found that the preparation and application of the gas atmosphere in Example 19 have better effect, which may be because H2O and Fe(OH)3colloid can create pores and optimize pores to a certain extent.

[0122] 2. Explore the influence of different condition parameters on the application of heterogeneous catalysts;

[0123] Comparative Example 3: The difference from Example 1 is that air drying is used in step S2-1 until completely dry;

[0124] Comparative Example 4: The difference from Example 1 is that the pressure is kept constant at 300 kPa in the pyrolysis method;

[0125] Examples 1-3, Examples 6-7, Examples 10-11, and Comparative Examples 3-4 are compared, as shown in Table 3;

[0126] Table 3: Results of different condition parameters on the application of heterogeneous catalysts

[0127]

[0128] From Table 3, comparing Example 1 with Comparative Example 3, it can be found that vacuum drying and freeze-drying of Example 1 are more preferred, although freeze-drying will reduce the surface area, but through the temperature difference treatment before and after the steps, the prepared heterogeneous catalyst has better catalytic effect;

[0129] Comparing Example 1 with Comparative Example 4, it can be seen that in the S2-2 pyrolysis method, the change of pressure is more beneficial to the performance of the heterogeneous catalyst;

[0130] Comparing Comparative Example 1, Example 2 and Example 3, it can be found that the raw material components of Example 1 are more preferred;

[0131] Comparing Comparative Example 1, Example 6 and Example 7, it can be found that the pyrolysis preparation parameters in the preparation of the heterogeneous catalyst of Example 1 are more preferred

[0132] Comparing Comparative Example 1, Example 10 and Example 11, it can be found that the pyrolysis preparation parameters in the preparation of the heterogeneous catalyst of Example 1 are more preferred, and the pressure is not the higher the better.

[0133] 3, explore the influence of different multi-level hole treatments on the application of heterogeneous catalysts;

[0134] Examples 12-16, Examples 19-21 are compared, as shown in Table 4;

[0135] Table 4 Different multi-level hole treatments on the application of heterogeneous catalysts

[0136]

[0137]

[0138] As can be seen from Table 4, comparing Comparative Example 12, Example 13, Example 14, it can be found that the temperature and time parameters of Example 12 are more preferred; comparing Comparative Example 19, Example 20 and Example 21, it can be found that the gas atmosphere components of Example 19 are more preferred.

Claims

1. A process for the preparation of a highly efficient, anti-interference, environmentally friendly heterogeneous catalyst, characterized in that, The method comprises the following steps: S1, preparing raw biochar BC: The sludge is air-dried for 23-25 h, then ground and crushed, and passed through a 100-mesh sieve to obtain a sludge powder. The sludge powder is placed in a tube furnace under a nitrogen protective atmosphere, heated to 550-610 ℃ at a heating rate of 10 ℃ / min, and then pyrolyzed for 2 h, and then cooled to room temperature. The sludge powder is washed with 1 mol / L hydrochloric acid and soaked for 12-13 h, and then washed with deionized water multiple times until the deionized water washing liquid is neutral, and then dried and ground to obtain raw biochar BC. The raw biochar BC is subjected to multi-level pore treatment to obtain multi-level porous carbon; The method for the multi-level pore treatment in step S1 is as follows: S1-1, mixing the raw biochar BC with water accounting for 65% of the mass of the raw biochar BC, and performing a hydrothermal carbonization reaction at 200-220 ℃; after the hydrothermal carbonization reaction, the reaction product is cooled to room temperature, and then sequentially washed with hydrochloric acid and deionized water until the pH of the deionized water washing liquid is neutral, and then dried to obtain hydrothermal carbon; S1-2, spraying an activating agent A accounting for 3-4% of the mass of the hydrothermal carbon on the surface of the hydrothermal carbon, placing the hydrothermal carbon in a tube furnace, heating and activating the hydrothermal carbon at 400-450 ℃ under a nitrogen atmosphere for 1-2 h, then taking out the hydrothermal carbon, sequentially washing the hydrothermal carbon with hydrochloric acid and deionized water until the pH of the deionized water washing liquid is neutral, and then drying the hydrothermal carbon to obtain primary pore carbon; S1-3, then soaking the primary pore carbon in an activating agent B, taking out the primary pore carbon after 10-15 min, placing the primary pore carbon in a tube furnace, heating and activating the primary pore carbon at 460-500 ℃ under a gas atmosphere for 1-2 h, then taking out the primary pore carbon, sequentially washing the primary pore carbon with hydrochloric acid and deionized water until the pH of the deionized water washing liquid is neutral, and then drying the primary pore carbon to obtain multi-level porous carbon; the method for forming the gas atmosphere is as follows: mixing and stirring H2O and Fe(OH)3 colloid at a mass ratio of 100:2-5, and atomizing the mixture into mixed droplets, and then circulating the mixed droplets into the tube furnace together with N2 to form a constant-flow gas atmosphere; wherein the constant-flow speed is 1.5-2 L / min; wherein the activating agent A is obtained by mixing fatty acid potassium and hexadecylamine at a mass ratio of 1:1, and the activating agent B is potassium laurate; S2, preparing a heterogeneous catalyst by a pyrolysis method: S2-1, adding FeCl3·6H2O, urea and multi-level porous carbon to pure water in sequence at a ratio of 100 mL:2 mmol:2-12 mmol:5 g; the adding method is as follows: first, adding FeCl3·6H2O and urea to pure water, stirring and heating, heating to 50-60 ℃, then adding half the mass of the multi-level porous carbon, obtaining a mixed system, then stirring and drying the mixed system under a vacuum environment until the volume of the mixed system is 50 mL; then adding the remaining half the mass of the multi-level porous carbon, stirring, and then freeze-drying until completely dry to obtain a dry powder; S2-2, the dry powder obtained in step S2-1 is placed in a tube furnace, and pyrolysis is performed under a nitrogen protective atmosphere, the pyrolysis temperature is 750-850℃, the pyrolysis is completed after heat preservation for 1h, and then cooling to room temperature; then washed with deionized water and ethanol for several times until the washing liquid is neutral, and finally dried, ground, and sieved to obtain a heterogeneous catalyst.

2. The method for preparing the highly efficient, interference-resistant, and environmentally friendly heterogeneous catalyst as described in claim 1, characterized in that, The drying in the vacuum environment in step S2-1 is performed by using a vacuum dryer at a pressure of 200-300Pa; the freeze drying is performed at-60--50℃.

3. The method for preparing the highly efficient, interference-resistant, and environmentally friendly heterogeneous catalyst as described in claim 2, characterized in that, The freeze drying method is: first, using a freeze dryer to reduce the temperature to-30℃ at a rate of 2-4℃ / min, and keep for 5-10min, and then reduce the temperature to-60--50℃ at a rate of 5-7℃ / min until completely dry.

4. The method for preparing the highly efficient, interference-resistant, environmentally friendly heterogeneous catalyst as described in claim 1, characterized in that, In step S2-2, the method of temperature rising pyrolysis is: first, starting from room temperature, the temperature is raised at a rate of 8-10℃ / min, when the temperature rises to 105-115℃, the pressure in the tube furnace is increased to 200-300kPa, when the temperature rises to 130-135℃, the pressure is reduced to 160-250kPa, the temperature rising rate is reduced to 5-7℃ / min, when the temperature rises to 300℃, the pressure is kept at 280-300kPa, until the pyrolysis temperature is reached, the pressure is reduced at a rate of 5kPa / min until the pyrolysis is completed.

5. The use of the heterogeneous catalyst prepared by the process for the preparation of a highly efficient anti-interference environmentally friendly heterogeneous catalyst according to claim 1, characterized in that, The heterogeneous catalyst is applied to groundwater pollution remediation.

6. Use of the highly efficient anti-interference environmentally friendly heterogeneous catalyst according to claim 5, characterized in that, The underground contaminated water contains SMX contaminants and Ca 2+ , Cl - , NO3 - , SO4 2- , HCO3 - , CO3 2- interfering ions.

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