CN112023925A - Preparation method and application of livestock and poultry manure biochar loaded nano zero-valent iron composite material - Google Patents

Abstract

The invention belongs to the field of waste resource utilization and water treatment technology, and discloses a preparation method of a livestock and poultry manure biochar-loaded nano-zero-valent iron composite material and an application of rapidly removing sulfamethoxazole. The preparation method of the livestock and poultry manure biochar-loaded nano-zero-valent iron composite material of the present invention includes the following steps: (1) taking livestock and poultry manure and drying it to a constant weight, heating and cracking to prepare biochar, and using hydrochloric acid and hydrofluoric acid for the biochar Soak in mixed acid, rinse with water to pH 6.7-7.3, dry to constant weight, grind, and sieve; (2) add the sieved biochar into ferrous sulfate solution, stir evenly, and place under nitrogen protection Slowly add sodium borohydride solution dropwise to obtain a suspension; (3) filter the suspension, wash it, dry it, and grind it into powder. The biochar-loaded nano-zero-valent iron composite material prepared by the method has good degradation effect on wastewater containing sulfamethoxazole and/or sulfisoxazole, has strong stability and can be reused.

Description

Preparation method and application of livestock and poultry manure biochar-loaded nano-zero valent iron composite material

technical field

The invention relates to the field of waste resource utilization and the technical field of water treatment, in particular to a preparation method of a livestock and poultry manure biochar-loaded nano-zero-valent iron composite material and a method for rapidly removing sulfamethoxazole and/or sulfisoxazole application.

Background technique

In recent years, with the increase in the variety of antibiotics, the use of antibiotics has become increasingly widespread, among which sulfamethoxazole (SMX) is one of the common antibiotics and is frequently detected in the water environment. The long-term residues of SMX are extremely harmful to the stability of water ecosystems and human health. However, it is difficult to effectively remove SMX antibiotics by traditional sewage treatment technologies.

In the prior art, for example, patent CN104261504 discloses a method for utilizing modified bamboo charcoal to remove sulfamethoxazole in a water body. After the bamboo charcoal is successively subjected to pulverization, ultrasonic treatment, dipping method loading iron oxide and freeze-drying, modified bamboo charcoal is obtained, The modified bamboo charcoal is used as a filler or adsorbent to adsorb and remove sulfamethoxazole in water, but the method requires a large amount of adsorbent, and the adsorption time is long, and the efficiency is low. Another example is patent CN106914216, which discloses the preparation of livestock and poultry manure biochar and a method for removing sulfonamide antibiotics from water. Making biochar; (2) soaking the livestock and poultry manure biochar obtained in step (1) with a 1:1 mixed acid of hydrochloric acid and hydrofluoric acid, washing with water to about neutrality, drying to constant weight, grinding, sieving; (3) putting the biochar adsorbent obtained in step (2) into a water body containing sulfonamide antibiotics to adsorb and remove the sulfonamide antibiotics. This method also has the problem of low efficiency, and it takes 24 hours to reach the maximum adsorption capacity.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the above-mentioned background technology, and provide a preparation method of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material and the application of rapid removal of sulfamethoxazole and/or sulfisoxazole. In the present invention, the dried livestock and poultry manure biochar is added to the ferrous sulfate solution, and then sodium borohydride is added to stir and mix evenly in a nitrogen environment to prepare the biochar-loaded nano-zero-valent iron composite material for sulfamethoxazole and/or sulfamethoxazole-containing composite materials. The wastewater of sulfisoxazole has good degradation effect, strong stability and can be reused.

In order to achieve the purpose of the present invention, the preparation method of the livestock and poultry manure biochar-loaded nano-zero-valent iron composite material of the present invention comprises the following steps:

(1) Take livestock and poultry manure and dry it to a constant weight, then heat and crack it to make biochar, soak the obtained livestock and poultry manure biochar with a mixed acid of hydrochloric acid and hydrofluoric acid in a volume ratio of 1:0.8-1.2, and wash it with water to pH6.7-7.3, dried to constant weight, ground, sieved;

(2) adding the biochar obtained by sieving in step (1) into the ferrous sulfate solution, stirring and mixing evenly, under nitrogen protection, slowly adding sodium borohydride solution dropwise to obtain a suspension;

(3) suction filtration of the suspension obtained in step (2), drying in a vacuum oven after cleaning, and then grinding into powder to obtain livestock and poultry manure biochar-loaded nano-zero-valent iron composite material.

Preferably, in some embodiments of the present invention, the volume ratio of hydrochloric acid and hydrofluoric acid in the step (1) is 1:1.

Preferably, in some embodiments of the present invention, the livestock manure is cow manure.

Further, in the pyrolysis, the livestock and poultry manure is ground to 2-6 cm, sealed with tin foil, and thermally pyrolyzed at a high temperature of 550-650° C. for 5-7 hours under anoxic conditions.

Further, in the step (1), the concentration of hydrochloric acid is 0.9-1.1 mol/L, and the concentration of hydrofluoric acid is 0.9-1.1 mol/L.

Further, in the step (1), the soaking time is 10-14h, the soaking process is accompanied by mechanical agitation, and the soaking process is repeated 2-4 times.

Further, the drying to constant weight is 55-65°C for 22-26h.

Further, the sieving is to pass through a 60-mesh sieve.

Further, the concentration of the ferrous sulfate solution is 0.035-0.045mol/L.

Further, the concentration of the sodium borohydride solution is 0.09-0.11 mol/L, and the dropping rate is between 12 mL/min-14 mL/min.

Further, the molar ratio of the sodium borohydride solution and the ferrous sulfate solution is 2:1.

Further, the cleaning in the step (3) is cleaning with water.

Further, in the step (3), the oven temperature is 55-65° C., and the drying time is 7-9h.

Further, the mass ratio of carbon to iron in the livestock and poultry manure biochar-loaded nano-zero-valent iron composite material is 1/4-1/2, or 3.

Preferably, in some embodiments of the present invention, the mass ratio of carbon to iron in the livestock and poultry manure biochar-loaded nano-zero-valent iron composite material is 1:4, 1:3, 1:2 or 3:1, more preferably 1:3.

On the other hand, the present invention also provides an application of the aforementioned livestock and poultry manure biochar-loaded nano-zero-valent iron composite material, that is, adding the livestock and poultry manure biochar-loaded nano-zero-valent iron composite material to sulfamethoxazole-containing and and/or sulfisoxazole solution to remove sulfamethoxazole.

Preferably, in the application of the livestock and poultry manure biochar-loaded nano-zero-valent iron composite material, the initial concentration of sulfamethoxazole and sulfisoxazole in the solution containing sulfamethoxazole and/or sulfisoxazole and the addition of The mass ratio of the livestock and poultry manure biochar-loaded nano-zero-valent iron composite material is 0.9-1.2g/L:5g.

Further, the pH of the solution containing sulfamethoxazole and/or sulfisoxazole is 2-10, preferably pH 4-10, more preferably 4-6.

Compared with the prior art, the advantages of the present invention are as follows:

(1) The biochar used in the present invention is formed by converting livestock and poultry manure waste, so the cost of raw materials is low, and the resource utilization of waste biomass is realized;

(2) The livestock and poultry manure biochar-loaded nano-zero-valent iron composite material prepared by the method of the present invention has an excellent removal effect on sulfamethoxazole wastewater, and the removal rate of methoxazole within 0.5 hours can reach more than 99%, And it can be reused 5 times and its removal rate can still reach 75%. The material also has excellent removal effect on sulfisoxazole, the removal rate can reach 99% in 0.5 hour, and the removal rate can still reach more than 75% after being reused 10 times.

Description of drawings

Figure 1 is the XPS image of cow dung biochar (BC) and cow dung biochar-loaded nano-zero-valent iron composite (BC/nZVI);

Fig. 2 is a partial detail view of Fe in the XPS diagram of the cow dung biochar-loaded nano-zero-valent iron composite (BC/nZVI) of Fig. 1;

Fig. 3 is the comparison diagram of the kinetic curve of removing sulfamethoxazole from the livestock and poultry manure biochar-loaded nano-zero-valent iron composite materials prepared with different C/Fe mass ratios of the present invention;

FIG. 4 is a comparison diagram of removal of sulfamethoxazole at different pHs of the cow dung biochar-loaded nano-zero-valent iron composite material with C:Fe=1:3 of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention. It should be understood that the following description is only used to explain the present invention, but not to limit the present invention.

As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device comprising the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such composition, step, method, article or device elements.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or a range bounded by a series of upper preferred values and lower preferred values, this should be understood as specifically disclosing any upper range limit or preferred value and any lower range limit or all ranges formed by any pairing of preferred values, whether or not the ranges are individually disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be construed to include the ranges "1 to 4," "1 to 3," "1 to 2," "1 to 2, and 4 to 5." , "1 to 3 and 5", etc. When numerical ranges are described herein, unless stated otherwise, the ranges are intended to include the endpoints and all integers and fractions within the range.

Furthermore, descriptions of the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" and the like described below mean specific features, structures, and descriptions in connection with the embodiment or example. , material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

Example 1

The preparation steps of C/Fe=1:1 biochar-loaded nano-zero-valent iron composites are as follows:

(1) get cow dung and dry it to constant weight, make biochar by thermal cracking at 600°C in muffle furnace for 6 hours, and use 1:1 hydrochloric acid and hydrofluoric acid (the concentration of hydrochloric acid is 1mol/L, the concentration of hydrofluoric acid is 1mol/L), soaked in mixed acid, rinsed with water until neutral, baked at 60°C for 24h to constant weight, ground, and passed through a 60-mesh sieve;

(2) 1.861g of ferrous sulfate heptahydrate was added to 250mL of water, then 0.375g of cow dung biochar passed through a 60-mesh sieve in step (1) was added, and the mixture was stirred and mixed evenly;

(3) under nitrogen protection (nitrogen flow rate is 20mL/min), by 0.5087g NaBH _The solution that is dissolved in 200mL water is slowly added dropwise to the solution obtained in step (2) to obtain a suspension;

(4) suction-filtering the suspension obtained in step (3), cleaning for three times and then drying in vacuum at 60° C. for 8h;

(5) grinding the biochar-loaded nano-zero-valent iron block obtained in step (4) into powder to obtain a C/Fe=1:1 bio-char-loaded nano-zero-valent iron composite material.

The obtained biochar-loaded nano-zero-valent iron composite material degraded sulfamethoxazole in a 1L three-necked flask. The added amount is 0.5g. During the reaction, the rotational speed of the magnetic stirrer was 200 r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution were fully mixed and uniform, and 250 μL of the supernatant was extracted from the reaction system within the set time and filtered through a 45 nm membrane. , the change of sulfamethoxazole concentration with time was measured, and the results are shown in Figure 3. In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 2

The preparation steps of C:Fe=1:2 biochar-supported nano-zero-valent iron catalytic material are as follows:

(1) get cow dung and dry it to constant weight, make biochar by thermal cracking at 600°C in muffle furnace for 6 hours, and use 1:1 hydrochloric acid and hydrofluoric acid (the concentration of hydrochloric acid is 1mol/L, the concentration of hydrofluoric acid is 1mol/L), soaked in mixed acid, rinsed with water until neutral, baked at 60°C for 24h to constant weight, ground, and passed through a 60-mesh sieve;

(2) 2.8421g of ferrous sulfate heptahydrate was added to 250mL of water, and then 0.25g of cow dung biochar passed through a 60-mesh sieve in step (1) was added, and the mixture was stirred and mixed evenly;

(3) under nitrogen protection (nitrogen flow rate is 40mL/min), by 0.6786g NaBH _The solution that is dissolved in 200mL water is slowly added dropwise to the solution obtained in step (2) to obtain suspension;

(4) the suspension obtained in step (3) was suction filtered, washed three times, and then dried in vacuum at 60°C for 8h;

(5) grinding the biochar-supported nano-zero-valent iron block obtained in step (4) into powder to obtain a C/Fe=1:2 bio-char-supported nano-zero-valent iron composite material.

The obtained biochar-loaded nano-zero-valent iron composite material degraded sulfamethoxazole in a 1L three-necked flask. The added amount is 0.5g. During the reaction, the rotational speed of the magnetic stirrer was 200 r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution were fully mixed and uniform, and 250 μL of the supernatant was extracted from the reaction system within the set time and filtered through a 45 nm membrane. , the change of sulfamethoxazole concentration with time was measured, and the results are shown in Figure 3. In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 3

The preparation steps of C:Fe=1:3 biochar-supported nano-zero-valent iron catalytic material are as follows:

(1) get cow dung and dry it to constant weight, make biochar by thermal cracking at 600°C in muffle furnace for 6 hours, and use 1:1 hydrochloric acid and hydrofluoric acid (the concentration of hydrochloric acid is 1mol/L, the concentration of hydrofluoric acid is 1mol/L), soaked in mixed acid, rinsed with water until neutral, baked at 60°C for 24h to constant weight, ground, and passed through a 60-mesh sieve;

(2) 2.7924g of ferrous sulfate heptahydrate was added to 250mL of water, then 0.1875g of cow dung biochar passed through a 60-mesh sieve in step (1) was added, and the mixture was stirred and mixed evenly;

(3) under nitrogen protection (nitrogen flow rate is 30mL/min), by 0.7633g NaBH _The solution that is dissolved in 200mL water is slowly added dropwise to the solution obtained in step (2) to obtain suspension;

(4) suction-filtering the suspension obtained in step (3), cleaning for three times and then drying in vacuum at 60° C. for 8h;

(5) grinding the biochar-supported nano-zero-valent iron block obtained in step (4) into powder to obtain a C/Fe=1:3 bio-char-supported nano-zero-valent iron composite material.

The obtained biochar-loaded nano-zero-valent iron composite material degraded sulfamethoxazole in a 1L three-necked flask. The added amount is 0.5g. During the reaction, the rotational speed of the magnetic stirrer was 200 r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution were fully mixed and uniform, and 250 μL of the supernatant was extracted from the reaction system within the set time and filtered through a 45 nm membrane. , the change of sulfamethoxazole concentration with time was measured, and the results are shown in Figure 3. In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 4

The preparation steps of C:Fe=1:4 biochar-supported nano-zero-valent iron catalytic material are as follows:

(1) get cow dung and dry it to constant weight, make biochar by thermal cracking at 600°C in muffle furnace for 6 hours, and use 1:1 hydrochloric acid and hydrofluoric acid (the concentration of hydrochloric acid is 1mol/L, the concentration of hydrofluoric acid is 1mol/L), soaked in mixed acid, rinsed with water until neutral, baked at 60°C for 24h to constant weight, ground, and passed through a 60-mesh sieve;

(2) 2.9786g of ferrous sulfate heptahydrate was added to 250mL of water, and then 0.15g of cow dung biochar passed through a 60-mesh sieve in step (1) was added, and the mixture was stirred and mixed evenly;

(3) under nitrogen protection (nitrogen flow rate is 30mL/min), by 0.8143g NaBH _The solution that is dissolved in 200mL water is slowly added dropwise to the solution obtained in step (2) to obtain suspension;

(4) suction-filtering the suspension obtained in step (3), cleaning for three times and then drying in vacuum at 60° C. for 8h;

(5) grinding the biochar-supported nano-zero-valent iron block obtained in step (4) into powder to obtain a C/Fe=1:4 bio-carbon-supported nano-zero-valent iron composite material.

The obtained biochar-loaded nano-zero-valent iron composite material degraded sulfamethoxazole in a 1L three-necked flask. The added amount is 0.5g. During the reaction, the rotational speed of the magnetic stirrer was 200 r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution were fully mixed and uniform, and 250 μL of the supernatant was extracted from the reaction system within the set time and filtered through a 45 nm membrane. , the change of sulfamethoxazole concentration with time was measured, and the results are shown in Figure 3. In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 5

The preparation steps of C:Fe=2:1 biochar-loaded nano-zero-valent iron composites are as follows:

(1) get cow dung and dry it to constant weight, make biochar by thermal cracking at 600°C in muffle furnace for 6 hours, and use 1:1 hydrochloric acid and hydrofluoric acid (the concentration of hydrochloric acid is 1mol/L, the concentration of hydrofluoric acid is 1mol/L), soaked in mixed acid, rinsed with water until neutral, baked at 60°C for 24h to constant weight, ground, and passed through a 60-mesh sieve;

(2) 1.2411g of ferrous sulfate heptahydrate was added to 250mL of water, and then 0.5g of cow dung biochar passed through a 60-mesh sieve in step (1) was added, and the mixture was stirred and mixed evenly;

(3) under nitrogen protection (the nitrogen flow rate is 40mL/min), the solution of _0.339g NaBH dissolved in 200mL water is slowly added dropwise into (2);

(4) suction-filtering the suspension obtained in step (3), cleaning for three times and then drying in vacuum at 60° C. for 8h;

(5) grinding the biochar-supported nano-zero-valent iron block obtained in step (4) into powder to obtain a C/Fe=2:1 bio-char-supported nano-zero-valent iron composite material.

The obtained biochar-loaded nano-zero-valent iron composite material degraded sulfamethoxazole in a 1L three-necked flask. The added amount is 0.5g. During the reaction, the rotational speed of the magnetic stirrer was 200 r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution were fully mixed and uniform, and 250 μL of the supernatant was extracted from the reaction system within the set time and filtered through a 45 nm membrane. , the change of sulfamethoxazole concentration with time was measured, and the results are shown in Figure 3. In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 6

The preparation steps of C:Fe=3:1 biochar-loaded nano-zero-valent iron composites are as follows:

(1) get cow dung and dry it to constant weight, make biochar by thermal cracking at 600°C in muffle furnace for 6 hours, and use 1:1 hydrochloric acid and hydrofluoric acid (the concentration of hydrochloric acid is 1mol/L, the concentration of hydrofluoric acid is 1mol/L), soaked in mixed acid, rinsed with water until neutral, baked at 60°C for 24h to constant weight, ground, and passed through a 60-mesh sieve;

(2) 0.9929g of ferrous sulfate heptahydrate was added to 250mL of water, and then 0.6g of cow dung biochar passed through a 60-mesh sieve in step (1) was added, and the mixture was stirred and mixed evenly;

(3) under nitrogen protection (nitrogen flow rate is 50mL/min), the solution of _0.2714g NaBH dissolved in 200mL water was slowly added dropwise into (2);

(4) suction-filtering the suspension obtained in step (3), cleaning for three times and then drying in vacuum at 60° C. for 8h;

(5) grinding the biochar-supported nano-zero-valent iron block obtained in step (4) into powder to obtain a C:Fe=3:1 bio-char-supported nano-zero-valent iron composite material.

The obtained biochar-loaded nano-zero-valent iron composite material degraded sulfamethoxazole in a 1L three-necked flask. The added amount is 0.5g. During the reaction, the rotational speed of the magnetic stirrer was 200 r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution were fully mixed and uniform, and 250 μL of the supernatant was extracted from the reaction system within the set time and filtered through a 45 nm membrane. , the change of sulfamethoxazole concentration with time was measured, and the results are shown in Figure 3. In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 7

The reaction steps of C:Fe=1:3 biochar-loaded nano-zero-valent iron composite material and initial water pH=2 sulfamethoxazole solution are as follows:

(1) Prepare 250 mL of sulfamethoxazole with an initial concentration of Co of 100 mg/L and pH=2;

(2) adding the sulfamethoxazole solution in (1) into a three-necked flask with a capacity of 1 L, and adding 0.5 g of the biochar-loaded nano-zero-valent iron composite material prepared in Example 3 to react;

(3) Set the rotation speed of the electric stirrer to 200r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution are fully mixed evenly;

(4) After extracting 250 μL of the supernatant from the reaction system within the set time and passing through a 45 nm mixed cellulose filter, the change of the concentration of sulfamethoxazole with time was measured. The results are shown in FIG. 4 . In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 8

The reaction steps of C:Fe=1:3 biochar-loaded nano-zero-valent iron composite material and initial water pH=4 sulfamethoxazole solution are as follows:

(1) Prepare 250 mL of sulfamethoxazole with an initial concentration of Co of 100 mg/L and pH=4;

(2) adding the sulfamethoxazole solution in (1) into a three-necked flask with a capacity of 1 L, and adding 0.5 g of the biochar-loaded nano-zero-valent iron composite material prepared in Example 3 to react;

(3) Set the rotation speed of the electric stirrer to 200r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution are fully mixed evenly;

(4) After extracting 250 μL of the supernatant from the reaction system within the set time and passing through a 45 nm mixed cellulose filter, the change of the concentration of sulfamethoxazole with time was measured. The results are shown in FIG. 4 . In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 9

The reaction steps of C:Fe=1:3 biochar-loaded nano-zero-valent iron composite material and initial water sulfamethoxazole solution are as follows:

(1) Prepare 250 mL of sulfamethoxazole with an initial concentration of Co of 100 mg/L and pH=6;

(2) adding the sulfamethoxazole solution in (1) into a three-necked flask with a capacity of 1 L, and adding 0.5 g of the biochar-loaded nano-zero-valent iron composite material prepared in Example 3 to react;

(3) Set the rotation speed of the electric stirrer to 200r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution are fully mixed evenly;

(4) After extracting 250 μL of the supernatant from the reaction system within the set time and passing through a 45 nm mixed cellulose filter, the change of the concentration of sulfamethoxazole with time was measured. The results are shown in FIG. 4 . In this example, the removal effect of sulfisoxazole is comparable to that of sulfamethoxazole, and it can be reused at least 5 times.

Example 10

The reaction steps of C:Fe=1:3 biochar-loaded nano-zero-valent iron composite material and initial water pH=7 sulfamethoxazole solution are as follows:

(1) Prepare 250 mL of sulfamethoxazole with an initial concentration of Co of 100 mg/L and pH=7;

(2) adding the sulfamethoxazole solution in (1) into a three-necked flask with a capacity of 1 L, and adding 0.5 g of the biochar-loaded nano-zero-valent iron composite material prepared in Example 3 to react;

(3) Set the rotation speed of the electric stirrer to 200r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution are fully mixed evenly;

(4) After extracting 250 μL of the supernatant from the reaction system within the set time and passing through a 45 nm mixed cellulose filter, the change of the concentration of sulfamethoxazole with time was measured. The results are shown in FIG. 4 . This example is comparable to sulfamethoxazole for removal of sulfisoxazole.

Example 11

The reaction steps of C:Fe=1:3 biochar-loaded nano-zero-valent iron composite material and initial water pH=10 sulfamethoxazole solution are as follows:

(1) Prepare 250 mL of sulfamethoxazole with an initial concentration of Co of 100 mg/L and pH=10;

(2) adding the sulfamethoxazole solution in (1) into a three-necked flask with a capacity of 1 L, and adding 0.5 g of the biochar-loaded nano-zero-valent iron composite material prepared in Example 3 to react;

(3) Set the rotation speed of the electric stirrer to 200r/min, so that the biochar-loaded nano-zero-valent iron composite material and the solution are fully mixed evenly;

(4) After extracting 250 μL of the supernatant from the reaction system within the set time and passing through a 45 nm mixed cellulose filter, the change of the concentration of sulfamethoxazole with time was measured. The results are shown in FIG. 4 . This example is comparable to sulfamethoxazole for removal of sulfisoxazole.

Figure 1 shows the XPS images of cow dung biochar and cow dung biochar-loaded nano-zero-valent iron composites. Fig. 2 is a partial detail view of Fe of Fig. 1. It can be seen from Fig. 1 and Fig. 2 that the nano-zero valent iron particles are successfully loaded on the biochar carrier and have little effect on the structure of the biochar material.

Figure 3 is a comparison of kinetic curves of biochar-loaded nano-zero-valent iron composites prepared with different carbon-to-iron ratios to degrade sulfamethoxazole. It can be seen from Figure 3 that when C/Fe=3:1, the removal rate of sulfamethoxazole by biochar-loaded nano-zero-valent iron composite after 0.5 hours of reaction is only about 70%; when C/Fe=2:1 The removal rate of sulfamethoxazole by biochar-loaded nano-zero-valent iron composites was only about 19% after 0.5 hours of reaction; when C/Fe=1:1, the biochar-loaded nano-zero-valent iron after 0.5 hours of reaction The removal rate of sulfamethoxazole by the composite material is only about 25%; with the increase of the nano-zero valent iron content, the removal effect of the composite material on sulfamethoxazole is enhanced, when C/Fe=1:2, the reaction is 25min The removal rate of sulfamethoxazole by biochar-loaded nano-zero-valent iron composites was close to 100%; when C/Fe = 1:3, the biochar-loaded nano-zero-valent iron composites reacted for 5 minutes to sulfamethoxazole. The removal rate has reached 100%. When C/Fe=1:4, the reaction time and removal rate are basically the same as those when C/Fe=1:3. The economic cost of iron composites is lower than that of C/Fe=1:4, so it is best to choose nano-zero-valent iron composites supported by biochar with C/Fe=1:3.

Figure 4 shows the relationship between the removal rate and the reaction time at different pH when C/Fe=1:3. It can be seen that the reaction is the fastest when the pH value is weakly acidic, but the reaction time and the removal rate are different at neutral and weakly alkaline conditions. very small.

Those skilled in the art can easily understand that the above descriptions are only examples of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be Included in the protection scope of the present invention.

Claims (10)

1. a preparation method of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material, is characterized in that, the preparation method of described livestock and poultry manure bio-char-loaded nano-zero-valent iron composite material comprises the following steps: (1) Take livestock and poultry manure and dry it to a constant weight, then heat and crack it to make biochar, soak the obtained livestock and poultry manure biochar with a mixed acid of hydrochloric acid and hydrofluoric acid in a volume ratio of 1:0.8-1.2, and wash it with water to pH6.7-7.3, dried to constant weight, ground, sieved; (2) adding the biochar obtained by sieving in step (1) into the ferrous sulfate solution, stirring and mixing evenly, under nitrogen protection, slowly adding sodium borohydride solution dropwise to obtain a suspension; (3) suction filtration of the suspension obtained in step (2), drying in a vacuum oven after cleaning, and then grinding into powder to obtain livestock and poultry manure biochar-loaded nano-zero-valent iron composite material. 2. The preparation method of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material according to claim 1, wherein the volume ratio of hydrochloric acid and hydrofluoric acid in the step (1) is 1:1; preferably The livestock manure is cow manure. 3. the preparation method of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material according to claim 1, it is characterized in that, described cracking is to grind livestock and poultry manure to 2-6cm, tin foil seal, hypoxia 550-650 ℃ high temperature thermal cracking for 5-7 hours; preferably, in the step (1), the concentration of hydrochloric acid is 0.9-1.1 mol/L, and the concentration of hydrofluoric acid is 0.9-1.1 mol/L; preferably, the step (1) The soaking time is 10-14h, the soaking process is accompanied by mechanical agitation, and the soaking process is repeated 2-4 times. 4. The preparation method of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material according to claim 1, wherein the drying to constant weight is 55-65°C for 22-26h; preferably, the Said sieving is 60 mesh sieve. 5. The preparation method of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material according to claim 1, wherein the concentration of the ferrous sulfate solution is 0.035-0.045mol/L; The concentration of the sodium borohydride solution is 0.09-0.11 mol/L, and the dropping rate is between 12 mL/min-14 mL/min; preferably, the molar ratio of the sodium borohydride solution and the ferrous sulfate solution is 2:1. 6. The preparation method of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material according to claim 1, wherein the cleaning in the step (3) is water cleaning; preferably, the step (3) The oven temperature is 55-65°C, and the drying time is 7-9h. 7. The preparation method of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material according to claim 1, wherein the carbon-iron mass ratio in the livestock and poultry manure bio-char-loaded nano-zero-valent iron composite material is 1 /4-1/2, or 3; More preferably, it is 1:3. 8. The application of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material, characterized in that the application is to load the livestock and poultry manure bio-char with nano-zero-valent iron prepared by the preparation method according to any one of claims 1-7 The composite material is added to a solution containing sulfamethoxazole and/or sulfisoxazole to remove sulfamethoxazole. 9. The application of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material according to claim 8, characterized in that, in the solution containing sulfamethoxazole and/or sulfisoxazole, sulfamethoxazole, The ratio of the initial concentration of sulfisoxazole to the mass of the biochar-loaded nano-zero-valent iron composite material added to livestock and poultry manure is 0.9-1.2 g/L: 5 g. 10. The application of livestock and poultry manure biochar-loaded nano-zero-valent iron composite material according to claim 8, wherein the pH of the solution containing sulfamethoxazole and/or sulfisoxazole is 2-10 , preferably pH is 4-10, more preferably 4-6.

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