Biochar aerogel loaded pyrite composite material, method of making and use thereof

Abstract

The application discloses a biochar aerogel loaded pyrite composite material and a preparation method and application thereof, and relates to the technical field of composite materials. The preparation method of the biochar aerogel loaded pyrite composite material comprises the following steps: mixing pyrite, biochar aerogel, zero-valent iron and water, ultrasonically dispersing until uniform, obtaining a first solution, mixing vitamin C and the first solution, standing and reacting at 60-65 DEG C for 12-12.5 h, washing, drying, and obtaining the biochar aerogel loaded pyrite composite material. The addition of the biochar aerogel loaded pyrite composite material can regulate the community structure of microorganisms in DM cell suspension, improve the degradation capacity of TCE, and the degradation rate of TCE is higher when DM cell suspension and the biochar aerogel loaded pyrite composite material are added simultaneously or DM cell suspension is added after the biochar aerogel loaded pyrite composite material than when only DM cell suspension is added, and the degradation rate is increased by 1.77-2.76 times.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a biochar aerogel-supported pyrite composite material, its preparation method, and its application. Background Technology

[0002] Chlorinated organic compounds, such as polychlorinated biphenyls (PCBs), hexachlorobenzene, perchloroethylene, and trichloroethylene (TCE), are commonly found in pesticides and industrial cleaning solutions. TCEs are among the most widely distributed chlorinated organic compounds in aquatic environments, exhibiting characteristics such as volatility, toxicity, concealment, accumulation, and diversity. They pose a serious threat to public health and ecosystems. TCEs are widely used in industries such as machinery, chemicals, and pharmaceuticals, and often enter soil and aquatic environments through improper discharge of industrial and domestic wastewater, waste accumulation, site seepage, and leaks of toxic and hazardous chemicals, making TCEs one of the most common organic pollutants in soil.

[0003] Biodegradation is considered a promising technology for in-situ remediation of contaminated groundwater and soil. However, due to limitations imposed by the underground environment, indigenous functional microorganisms in soil often suffer from insufficient numbers, low activity, and slow growth, resulting in poor natural attenuation of organic pollutants. Existing research indicates that functional microbial degradation plays a dominant role in the natural attenuation of organic pollutants. Some organohalogen-respiring bacteria (OHRBs) can reduce and dechlorinate tetrachloroethylene (TCE). OHRBs include anaerobic bacteria such as *Bacillus*, *Dethiobacillus*, *Thiospirillum*, and *Geobacter*, which are widely distributed in various environments such as soil, sediments, and aquifers. However, microbial degradation of TCE alone faces challenges such as low degradation efficiency, long cycles, susceptibility to toxicity and inactivation due to high concentrations of TCE, and the inability to achieve complete TCE degradation, leading to the accumulation of the more toxic intermediate product, vinyl chloride. Therefore, improving the efficiency of microbial TCE degradation is crucial for achieving low-carbon remediation. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing biochar aerogel-supported pyrite composite material.

[0005] Another object of the present invention is to provide a biochar aerogel-supported pyrite composite material obtained by the above preparation method.

[0006] Another objective of this invention is to provide an application of the aforementioned biochar aerogel-supported pyrite composite material in the synergistic degradation of trichloroethylene by microorganisms. The biochar aerogel-supported pyrite composite material acts as a chemical reducing adsorbent, while the microorganisms act as a biodegrading agent, with both working synergistically. The zero-valent iron in the biochar aerogel-supported pyrite composite material accelerates the degradation rate of trichloroethylene, and the biochar aerogel in the composite material provides a growth environment and nutrients for the microorganisms.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] A method for preparing a biochar aerogel-supported pyrite composite material includes the following steps:

[0009] Step 1, pyrite (FeS2), biochar aerogel (CA), and zero-valent iron (Fe) are added. 0 Mix pyrite (FeS2), biochar aerogel (CA), and zero-valent iron with water and sonicate until uniformly dispersed to obtain a first solution, wherein the ratio of pyrite (FeS2), biochar aerogel (CA), and zero-valent iron by mass fraction is (0.5-1.5):(0.5-2):(0-1);

[0010] In step 1, the ratio of the mass fraction of the biochar aerogel (CA) to the volume fraction of water in step 1 is (0.5-1):(20-25), where the mass fraction is in g and the volume fraction is in mL.

[0011] In step 1, the ultrasound duration is 30–40 minutes.

[0012] In step 1, the preferred ratio of pyrite (FeS2), biochar aerogel (CA), and zero-valent iron by mass is (0.5-1):(1-2):(0.5-1).

[0013] Step 2: Mix vitamin C and the first solution, let stand at 60-65°C for 12-12.5 h, wash and dry to obtain biochar aerogel-supported pyrite composite material, wherein the ratio of vitamin C to biochar aerogel (CA) by mass is (2.5-5):(0.5-1).

[0014] In step 2, the washing process uses ethanol.

[0015] In step 2, the drying is carried out under vacuum conditions.

[0016] In step 2, the drying is freeze drying, and the drying time is 20 to 24 hours.

[0017] In the above technical solution, the pyrite (FeS2) is a powder with a particle size of 1-100 nm.

[0018] In the above technical solution, the method for preparing the biochar aerogel (CA) is as follows: KOH, NH4Cl, Na2S·9H2O and water are mixed and stirred until uniform to obtain solution A. Rhamnolipid is mixed with solution A and stirred at 0-5℃ for 2-2.5h. After drying, a biochar aerogel precursor is obtained. Under a nitrogen atmosphere, the biochar aerogel precursor is carbonized at 800-805℃ for 2-2.5h and washed until neutral to obtain biochar aerogel (CA). The ratio of KOH, NH4Cl and Na2S·9H2O by mass is (1-2):(2-4):(1-2), and the ratio of KOH and rhamnolipid by mass is (6.25-12.5):(5-10).

[0019] In the method for preparing biochar aerogel (CA), the drying is freeze drying.

[0020] In the method for preparing biochar aerogel (CA), the mass fraction of KOH and the volume fraction of water are in the ratio of (6.25–12.5):(20–40), where the mass fraction is in g and the volume fraction is in mL.

[0021] In the method for preparing biochar aerogel (CA), water is used for cleaning.

[0022] The above technical solution yields a biochar aerogel-supported pyrite composite material.

[0023] The above-mentioned biochar aerogel-supported pyrite composite material is used in the synergistic degradation of trichloroethylene by microorganisms.

[0024] In the above technical solution, the method for the synergistic degradation of trichloroethylene by the biochar aerogel-supported pyrite composite material and microorganisms is as follows: the biochar aerogel-supported pyrite composite material and DM cell suspension are added to the degradation solution containing TCE for degradation. The DM cell suspension is a microbial suspension. After adding the DM cell suspension, the OD value of the cells at 600 nm in the degradation solution is made to be 0.1-0.5. The microorganisms in the DM cell suspension, by number, include: 10%-20% Pseudomonas spp., 30%-40% Clostridium spp., 20%-40% Pseudomonas families, and 5%-20% Trichomonas spp.

[0025] In the above technical solution, biochar aerogel-supported pyrite composite material is first added to the liquid to be degraded, and allowed to stand for at least 24 hours. Then, DM cell suspension is added, and degradation is carried out under anaerobic and dark conditions.

[0026] In the above technical solution, the OD value of the DM cell suspension at 600nm is 1.1 to 1.3.

[0027] In the above technical solution, the temperature at which the biochar aerogel-supported pyrite composite material and microorganisms synergistically degrade trichloroethylene is 25-30℃.

[0028] In the above technical solution, after adding the biochar aerogel-supported pyrite composite material, the concentration of the biochar aerogel-supported pyrite composite material in the solution to be degraded is 0.01 to 1.0 g / L.

[0029] In the above technical solution, the method for obtaining DM cell suspension includes: soaking the chlorinated hydrocarbon-contaminated soil in physiological saline for at least 12 hours, acclimating it in a culture medium with gradually increasing TCE concentration to obtain a microbial community, suspending the microbial community in the culture medium, centrifuging during the logarithmic growth phase, discarding the supernatant, washing with sterile physiological saline, and storing it in sterile physiological saline to obtain DM cell suspension. The acclimation includes repeating the following steps multiple times: taking the supernatant into a culture medium containing TCE and culturing it in an anaerobic environment for 3 to 10 days.

[0030] In the above technical solution, the TCE concentration in the culture medium used for acclimatization is 10-50 mg / L.

[0031] In the above technical solution, the ratio of supernatant to TCE-containing culture medium is 1:(1-15) by volume.

[0032] In the above technical solution, the culture medium is a basic salt medium (MSM).

[0033] In the above technical solution, a vitamin solution is added to the basic salt medium (MSM) before use.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1. Trichloroethylene (TCE) can be degraded by microorganisms or by biochar aerogel-supported pyrite composites. However, the synergistic degradation of biochar aerogel-supported pyrite composites with microorganisms has a higher degradation efficiency. The addition of biochar aerogel-supported pyrite composites can regulate the community structure of microorganisms in DM cell suspension and improve the degradation ability of TCE. The degradation rate of TCE is higher when DM cell suspension and biochar aerogel-supported pyrite composites are added simultaneously or after biochar aerogel-supported pyrite composites are added, which is 1.77 to 2.76 times higher than when DM cell suspension is added alone.

[0036] 2. The preparation method of the biochar aerogel-supported pyrite composite material of the present invention is simple. Pyrite and zero-valent iron (Fe) are combined by ultrasonication and static vitamin C reduction. 0 ) Fixed on biochar aerogel;

[0037] 3. The DM cell suspension of the present invention has high environmental adaptability and can achieve good degradation efficiency with a small amount added, without the need for external nutrients.

[0038] 4. The degradation steps of first adding biochar aerogel-supported pyrite composite material to the solution to be degraded, and then adding DM cell suspension, can achieve complete degradation of TCE. Attached Figure Description

[0039] Figure 1 The diagram shows the abundance of microorganisms (T0 represents the community structure of microorganisms in the DM cell suspension in Example 1, and T1 represents the abundance of microorganisms and FeS2-Fe in the DM cell suspension). 0 (Microbial community structure after @CA co-processing);

[0040] Figure 2 A trend graph showing the effect of different concentrations of DM cell suspensions on TCE degradation rate;

[0041] Figure 3 Examples 4-7 illustrate the TCE removal effects.

[0042] Figure 4 Pyrite FeS2 and FeS2-Fe 0 FTIR plot of @CA composite material

[0043] Figure 5 Examples 14-19 show the degradation rate of TCE.

[0044] Figure 6 FeS2-Fe 0 The effect of CA concentration on the degradation rate of TCE;

[0045] Figure 7 Trend graphs showing the TCE removal effects of Examples 3, 14, 20, 15, 21, 19, and 22;

[0046] Figure 8 Trend graphs showing the effect of the order of adsorbent and DM cell suspension addition on TCE removal. (Examples 20-28) Detailed Implementation

[0047] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0048] The raw materials and their sources of purchase involved in the following embodiments are as follows:

[0049]

[0050]

[0051] The instruments and models involved in the following embodiments are as follows:

[0052] Planetary ball mill: F-P2000, Hunan Fukas Experimental Instrument Co., Ltd., Changsha, China;

[0053] Anaerobic incubator: HYQX-Ⅱ, Shanghai Yuejin Medical Instrument Co., Ltd., Shanghai, China.

[0054] Unless otherwise specified, the water used in the following examples is deionized water.

[0055] In the following examples, the degradation rate = (TCE concentration before reaction - TCE concentration after reaction) / TCE concentration before reaction. The concentration of TCE in the supernatant after the experiment is the TCE concentration after reaction, and the TCE concentration before reaction is 30 mg / L.

[0056] In the following examples, the anaerobic reaction under dark conditions was carried out as follows: the headspace vial was sealed with a cap containing a polytetrafluoroethylene gasket, and the headspace vial was placed in an anaerobic incubator for the reaction at a temperature of 30°C. After the reaction was completed, the headspace vial was removed from the anaerobic incubator.

[0057] Example 1

[0058] DM cell suspensions with high TCE degradation rates were obtained by extracting microbial communities from soil contaminated with chlorinated hydrocarbons.

[0059] A method for preparing DM cell suspension includes: adding 5g of chlorinated hydrocarbon-contaminated soil (the chlorinated hydrocarbon-contaminated soil was taken from the chlorinated hydrocarbon pollution remediation pilot plant of Beichen Campus of Hebei University of Technology) to a 50mL brown bottle 1 and adding 30mL of physiological saline, soaking at room temperature for 24h, adding 27mL of basal salt culture medium (MSM) containing 10mg / LTCE to another 50mL brown bottle 2, taking 3mL of supernatant from brown bottle 1 and adding it to brown bottle 2, sealing brown bottle 2 with a polytetrafluoroethylene gasket cap, and culturing in an anaerobic chamber for 7d to obtain the first culture medium;

[0060] Take another 50mL brown bottle 3, add 27mL of basal salt medium (MSM) containing 20mg / L TCE, add 3mL of the first culture medium to brown bottle 3, seal brown bottle 3 with a polytetrafluoroethylene gasket cap, and culture in an anaerobic chamber for 7 days to obtain the second culture medium;

[0061] Take another 50mL brown bottle 4, add 27mL of basal salt medium (MSM) containing 30mg / L TCE, add 3mL of the second culture medium to brown bottle 4, seal brown bottle 4 with a polytetrafluoroethylene gasket cap, and culture in an anaerobic chamber for 7 days to obtain the third culture medium;

[0062] Take another 50mL brown bottle 5, add 27mL of basal salt medium (MSM) containing 40mg / L TCE, add 3mL of the third culture medium to brown bottle 5, seal brown bottle 5 with a polytetrafluoroethylene gasket cap, and culture in an anaerobic chamber for 7 days to obtain the fourth culture medium;

[0063] Take another 50mL brown bottle 6, add 27mL of basal salt medium (MSM) containing 50mg / L TCE, add 3mL of the fourth culture medium to brown bottle 6, seal brown bottle 6 with a polytetrafluoroethylene gasket cap, and incubate in an anaerobic chamber for 7 days to obtain the fifth culture medium.

[0064] The fifth culture medium was centrifuged at 8000 rpm for 10 min to obtain the microbial community. The microbial community was then resuspended in basal salt medium (MSM), centrifuged at 8000 rpm at 4℃ for 10 min during the logarithmic growth phase, the supernatant was discarded, and the cells were washed three times with sterile physiological saline. The suspension was then stored in 5 mL of sterile physiological saline to obtain the DM cell suspension, with a cell OD value of 1.2 at 600 nm. The number of microorganisms in the DM cell suspension was as follows: Figure 1 As shown in column T0, it includes: 19% Pseudomonas spp., 37.5% Clostridium spp., 31.5% Pseudomonas families and 10.7% Trichomonas spp.

[0065] The basal salt medium (MSM) consists of: 10% v / v basal mineral salt medium (BMM), 1% v / v micro mineral solution, 0.25 mL / L resazurin, 2.292 g / L Tri-ethanesulfonic acid, 0.048 g / L Na2S·9H2O, 0.242 g / L L-cysteine, 0.0771 g / L DL-panthenol, 2.52 g / L NaHCO3, and water as a solvent.

[0066] The basic mineral salt medium (BMM) consists of: 1 g / L NaCl, 0.2 g / L KH2PO4, 0.5 g / L MgCl2·6H2O, 0.3 g / L NH4Cl, 0.3 g / L KCl, 0.015 g / L CaCl2·2H2O and water.

[0067] The trace mineral solution includes: 1.5 g / L FeCl2·4H2O, 0.1 g / L CoCl2·6H2O, 0.07 g / L ZnCl2, 0.006 g / L H3BO3, 0.036 g / L NaMoO4·2H2O, 0.024 g / L NiCl2·6H2O, 0.02 g / L CuCl2·2H2O, and water.

[0068] The pH of the basal salt medium (MSM) was 7.4. Before use, a vitamin solution was added to the MSM at a rate of 0.1 mL per 50 mL of MSM. The medium was then sterilized in an autoclave at 121°C for 30 minutes. This solution was used in the process of obtaining the DM cell suspension described above. The vitamin solution consisted of: 0.02 mg / L biotin, 0.02 mg / L folic acid, 0.1 mg / L pyridoxine hydrochloride, 0.05 mg / L riboflavin, 0.05 mg / L thiamine, 0.05 mg / L niacin, 0.05 mg / L pantothenic acid, 0.05 mg / L para-aminobenzoic acid, 0.001 mg / L vitamin B12, and water.

[0069] Example 2

[0070] Different volumes of the DM cell suspension obtained in Example 1 were centrifuged, and then mixed with basal salt medium (MSM) and brought to a final volume of 0.7 mL to obtain DM cell solution.

[0071] A method for TCE degradation includes: adding 7 mL of TCE aqueous solution with a concentration of 30 mg / L to a 20 mL headspace vial, purging with ultrapure N2 to remove oxygen, then adding 0.7 mL of DM cell lysate to achieve a cell OD value of 0.0375, 0.075, 0.1125, 0.15, 0.30, or 0.45 at 600 nm, adjusting the pH to 8.0, allowing the mixture to stand in the dark for 48 h for anaerobic reaction at 30 °C, analyzing the TCE concentration in the supernatant, and calculating the TCE degradation rate.

[0072] like Figure 2 As shown, by adjusting different OD values, it was found that the degradation rate of TCE increased with increasing OD value from 0.0375 to 0.15, increasing from 6% to 31%. This may be due to the increased addition of microorganisms, leading to increased production of dechlorination enzymes and thus improved TCE degradation. When the OD value was higher than 0.15, the TCE degradation rate did not increase and even slightly decreased. This is because when the microbial concentration exceeded the optimal level, the enzymes secreted by the microorganisms could not be fully and effectively utilized, resulting in no further increase in the degradation rate. Simultaneously, due to limited nutrients, competition for nutrients among microorganisms inhibited their growth and reproduction, further reducing degradation efficiency.

[0073] Example 3

[0074] A method for TCE degradation includes: adding 7 mL of a 30 mg / L TCE aqueous solution to a 20 mL headspace vial; purging with ultrapure N2 to remove oxygen; adding 0.7 mL of the DM cell suspension from Example 1 to achieve a cell OD value of 0.15 at 600 nm; adjusting the pH to 8.0; and sealing the headspace vial with a cap containing a polytetrafluoroethylene gasket to ensure the experiment is conducted under anaerobic conditions. The headspace vial is placed in an anaerobic incubator and allowed to react anaerobically in the dark for 48 h at a reaction temperature of 30 °C. After the experiment, the headspace vial is removed from the anaerobic incubator, and the concentration of TCE in the supernatant is analyzed to calculate the TCE degradation rate.

[0075] Example 4

[0076] A TCE degradation method is basically the same as in Example 3, except that the TCE aqueous solution is a mixture of TCE and lake water (taken from Hebei University of Technology).

[0077] Example 5

[0078] A TCE degradation method is basically the same as in Example 3, except that the TCE aqueous solution is a mixture of TCE and sterilized lake water (the lake water was taken from Hebei University of Technology, and sterilization was carried out by keeping the lake water at 121°C for 30 minutes).

[0079] Example 6

[0080] A TCE degradation method is basically the same as that in Example 4, except that the TCE aqueous solution also contains 10 mg / L of chromium sulfate.

[0081] Example 7

[0082] A TCE degradation method is basically the same as that in Example 4, except that the TCE aqueous solution also contains 10 mg / L of benzoquinone.

[0083] After testing, the degradation rate of TCE in Examples 4-7 was as follows: Figure 3As shown in Examples 4 and 5, it can be seen that whether or not the actual water body (lake water) is sterilized, it does not interfere with the ability of the DM cell suspension to degrade TCE (the degradation rate remains at around 31%), indicating that the microorganisms present in the actual water body do not affect the degradation ability of the DM cell suspension. Meanwhile, it can be seen from Examples 6 and 7 that when chromium sulfate or benzoquinone coexist, the ability of the DM cell suspension to degrade TCE is not significantly affected (the presence of chromium sulfate slightly reduces the TCE degradation rate from 31% to 27.5%). Overall, the degradation ability of the DM cell suspension for TCE is relatively stable, which is beneficial for its subsequent application in actual contaminated sites.

[0084] Example 8

[0085] A method for preparing pyrite (FeS2) includes: ultrasonically treating natural pyrite particles (20 kHz) for 1 h to remove impurities; placing 1.5 g of the ultrasonically treated natural pyrite particles in a 500 mL zirconia ball mill jar; and adding zirconia balls (in a mass ratio of large balls) to the zirconia ball mill jar. Middle ball Small ball The proportion of natural pyrite particles to zirconia balls was increased to a mass ratio of 1:100. N2 (>99%) was introduced into the zirconia ball mill jar for 30 min. The zirconia ball mill jar was then sealed and placed in a planetary ball mill. The jar was ball-milled at 600 rpm for 2 h at room temperature to obtain pyrite precursor (powder). The precursor was washed three times with ethanol and deionized water to remove impurities. Finally, it was dried at 105℃ for 3 h to obtain pyrite. The pyrite was tested and found to be a powder with a particle size of 1-100 nm.

[0086] Example 9

[0087] A method for preparing biochar aerogel (CA) includes: dissolving KOH, NH4Cl, and Na2S·9H2O (by mass, the ratio of KOH, NH4Cl, and Na2S·9H2O is 1:2:1, and the total mass of KOH, NH4Cl, and Na2S·9H2O is 25g) in 20mL of water, stirring until homogeneous to obtain solution A; mixing solution A with 5g of rhamnolipid, stirring at 0℃ for 2h (stirring reaction), freeze-drying to form an aerogel, obtaining a biochar aerogel precursor; carbonizing the biochar aerogel precursor in a tube furnace: under vacuum conditions, heating to 800℃ at a rate of 5℃ / min, holding in a tube furnace under N2 flow at 800℃ for 2h, thoroughly rinsing several times with deionized water to remove unreacted reagents, washing until neutral, to obtain biochar aerogel (CA).

[0088] Examples 10-13

[0089] A method for preparing a biochar aerogel-supported pyrite composite material includes the following steps:

[0090] Step 1: Pyrite (FeS2) obtained in Example 8, biochar aerogel (CA) obtained in Example 9, and zero-valent iron (Fe) are mixed together. 0 The mixture is stirred with water and sonicated for 30 minutes until uniformly dispersed to obtain the first solution, which contains pyrite (FeS2), biochar aerogel (CA), and zero-valent iron (Fe). 0 The sum of the masses of pyrite (FeS2), biochar aerogel (CA), and zero-valent iron (Fe) is 2g. By mass fraction, the components are: pyrite (FeS2), biochar aerogel (CA), and zero-valent iron (Fe). 0 The ratio of the mass fraction of biochar aerogel (CA) to the volume fraction of water in step 1 is X, and the unit of mass fraction is g, and the unit of volume fraction is mL.

[0091] Step 2: Mix vitamin C and the first solution, let stand at 60°C for 12 hours to react, wash with ethanol to remove impurities, and freeze dry under vacuum for 24 hours to obtain biochar aerogel-supported pyrite composite material, wherein the ratio of vitamin C to biochar aerogel (CA) by mass is Z.

[0092] Example X Y Z serial number Example 10 1.5：0.5：0 0.5：20 2.5：0.5 <![CDATA[FeS2@CA <!-- 7 -->]]> Example 11 0.75：0.5：0.75 0.5：20 2.5：0.5 <![CDATA[FeS2-Fe 0 @CA]]> Example 12 1：1：0 1：20 5：1 <![CDATA[FeS2@CA]]> Example 13 0.5：1：0.5 1：20 5：1 <![CDATA[FeS2-Fe 0 @CA]]>

[0093] The surface functional groups of the pyrite (FeS2) prepared in Example 8 and the biochar aerogel-supported pyrite composite material in Example 13 were characterized, such as... Figure 4 As shown, pyrite alone has few functional groups on its surface, mainly C=C, and its adsorption capacity for TCE is weak. However, when combined with biochar aerogel, the types and strengths of functional groups on the surface of the biochar aerogel-loaded pyrite composite material are significantly improved. For example, the appearance and increased strength of -COOH and COC are beneficial to the adsorption of TCE by the composite material.

[0094] Examples 14-19

[0095] A method for TCE degradation includes: adding 7 mL of a 30 mg / L TCE aqueous solution to a 20 mL headspace vial; purging with ultrapure N2 to remove oxygen; adding an adsorbent to achieve a concentration of 0.5 g / L in the TCE aqueous solution; sealing the headspace vial with a cap containing a polytetrafluoroethylene gasket to ensure all experiments are conducted under anaerobic conditions; placing the headspace vial in an anaerobic incubator and allowing it to react anaerobically in the dark for 48 hours at a temperature of 30°C; and removing the headspace vial from the anaerobic incubator after the experiment and analyzing the TCE concentration in the supernatant. The adsorbent is one of the following: pyrite prepared in Example 8; biochar aerogel (CA) prepared in Example 9; or biochar aerogel-supported pyrite composite material prepared in Examples 10-13.

[0096] Example Adsorbent Example 14 Example 8 Example 15 Example 9 Example 16 Example 10 Example 17 Example 11 Example 18 Example 12 Example 19 Example 13

[0097] The surface functional groups of the biochar aerogel-supported pyrite composite material in Example 19 after reaction were characterized as follows: Figure 4 As shown.

[0098] like Figure 5 As shown, Example 19 exhibits a higher degradation rate of TCE compared to Example 14. This is because biochar aerogel (CA) effectively combines FeS2 and Fe... 0 Dispersion, making FeS2-Fe 0 @CA has a larger specific surface area and more adsorption sites. Simultaneously, it can increase the adsorption of FeS2 and Fe. 0 Solubility in water. FeS2 and Fe 0 When combined with biochar aerogel, the FeS2-Fe content increases with the increase of the proportion of biochar aerogel added. 0 The increasing degradation rate of TCE by @CA indicates that increasing the proportion of biochar aerogel is more conducive to the degradation of FeS2 and Fe. 0 The fractionation and activity of the TCE are enhanced, thereby achieving efficient degradation of TCE.

[0099] The above experimental results show that the FeS2-Fe prepared in Example 13 0 @CA showed the best removal effect on TCE, therefore the FeS2-Fe prepared in Example 13 was selected. 0 @CA is used for further research.

[0100] Investigating FeS2-Fe 0 @Effect of CA concentration on TCE removal efficiency. Experimental conditions: 7 mL of TCE aqueous solution with a concentration of 30 mg / L was added to a 20 mL headspace vial, ultrapure N2 was bubbled through to remove oxygen, and then the adsorbent, FeS2-Fe prepared in Example 13, was added. 0 @CA, the adsorbent concentration in the TCE aqueous solution is one of 0.01, 0.02, 0.05, 0.1, 0.3, 0.5, and 1 g / L. The headspace vial is sealed with a cap containing a PTFE gasket, ensuring all experiments are conducted under anaerobic conditions. The headspace vial is placed in an anaerobic incubator and allowed to react anaerobically in the dark for 7 days at 30℃. After the experiment, the headspace vial is removed from the anaerobic incubator, and the TCE concentration in the supernatant is analyzed to calculate the TCE degradation rate. The test results are as follows: Figure 6 As shown in the figure. It can be seen that improving FeS2-Fe 0 @CA concentration can significantly improve the material's ability to degrade TCE, with FeS2-Fe 0Increasing the CA concentration from 0.01 g / L to 0.5 g / L improved the TCE degradation rate from 25% to 73.1%. However, further increasing the concentration to 1 g / L resulted in no further improvement in the TCE degradation rate. Considering the limitations of microbial degradation of TCE, the next step is to combine the material with microorganisms to enhance its TCE degradation capabilities.

[0101] Example 20

[0102] A method for TCE degradation includes: adding 7 mL of a 30 mg / L TCE aqueous solution to a 20 mL headspace vial; purging with ultrapure N2 to remove oxygen; simultaneously adding pyrite (FeS2) prepared in Example 8 and 0.7 mL of the DM cell suspension from Example 1 to achieve a pyrite (FeS2) concentration of 0.5 g / L in the TCE aqueous solution and a cell OD value of 0.15 at 600 nm; adjusting the pH to 8.0; and sealing the headspace vial with a cap containing a polytetrafluoroethylene gasket to ensure the experiment is conducted under anaerobic conditions. The headspace vial is placed in an anaerobic incubator and allowed to react anaerobically in the dark for 48 h at a reaction temperature of 30 °C. After the experiment, the headspace vial is removed from the anaerobic incubator, and the concentration of TCE in the supernatant is analyzed to calculate the TCE degradation rate.

[0103] Example 21

[0104] A TCE degradation method is basically the same as that in Example 20, except that "pyrite (FeS2) prepared in Example 8" is replaced with "biochar aerogel (CA) prepared in Example 9".

[0105] Example 22

[0106] A TCE degradation method is basically the same as that in Example 20, except that "pyrite (FeS2) prepared in Example 8" is replaced with "pyrite composite material supported by biochar aerogel prepared in Example 13".

[0107] The surface functional groups of the biochar aerogel-supported pyrite composite material in Example 22 after reaction were characterized as follows: Figure 4 As shown.

[0108] like Figure 7As shown, TCE can be degraded by the DM cell suspension of Example 1, or directly by adding an adsorbent. Regardless of whether the adsorbent is pyrite, biochar aerogel, or a biochar aerogel-supported pyrite composite material, the simultaneous addition of the DM cell suspension and the adsorbent improves the TCE removal rate, indicating that the synergistic effect of materials and microorganisms can achieve efficient TCE degradation. The highest TCE removal rate, reaching 76.5%, was achieved when both the biochar aerogel-supported pyrite composite material and the DM cell suspension were added (Example 22). This may be because the biochar aerogel-supported pyrite composite material itself has a strong TCE degradation capacity, and the addition of the biochar aerogel-supported pyrite composite material can regulate the microbial community structure in the DM cell suspension.

[0109] The community structure of microorganisms in the reaction system after the combined action of biochar aerogel-supported pyrite composite material and DM cell suspension in Example 22 was tested. The proportion of each type of microbial community, by number, is as follows: Figure 1 As shown in column T1, from Figure 1 It can be seen that, compared with the original DM cell suspension (i.e., T0), the microbial community structure in the reaction system underwent significant changes after the synergistic degradation of TCE by the biochar aerogel-supported pyrite composite material. In particular, the proportion of *Pseudomonas* increased from 19% to 62%, and *Pseudomonas* has been proven to have the ability to degrade TCE. Secondly, a new genus, *Dalfordia*, appeared in the community at 10.5%, and this genus has also been proven to have the ability to degrade TCE. In summary, the biochar aerogel-supported pyrite composite material has the function of regulating the microbial community structure in the DM cell suspension, significantly increasing the proportion of genera capable of degrading TCE. This also explains the phenomenon that the synergistic effect of the two enhances the TCE degradation ability.

[0110] Furthermore, the effect of the order of adding the adsorbent and DM cell suspension on the TCE degradation rate was investigated.

[0111] Example 23

[0112] A method for TCE degradation includes: adding 7 mL of a 30 mg / L TCE aqueous solution to a 20 mL headspace vial; purging with ultrapure N2 to remove oxygen; adding 0.7 mL of the DM cell suspension from Example 1 to adjust the cell OD value at 600 nm to 0.15; adjusting the pH to 8.0; and allowing the solution to stand anaerobically in the dark for 24 h. Then, adding pyrite (FeS2) prepared in Example 8 to achieve a pyrite (FeS2) concentration of 0.5 g / L in the TCE aqueous solution; and allowing the solution to stand anaerobicly in the dark for 24 h. The concentration of TCE in the supernatant is analyzed, and the TCE degradation rate is calculated.

[0113] Example 24

[0114] A TCE degradation method is basically the same as that in Example 23, except that "pyrite (FeS2) prepared in Example 8" is replaced with "biochar aerogel (CA) prepared in Example 9".

[0115] Example 25

[0116] A TCE degradation method is basically the same as that in Example 23, except that "pyrite (FeS2) prepared in Example 8" is replaced with "pyrite composite material supported on biochar aerogel prepared in Example 13".

[0117] Example 26

[0118] A method for TCE degradation includes: adding 7 mL of a 30 mg / L TCE aqueous solution to a 20 mL headspace vial; purging with ultrapure N2 to remove oxygen; adding pyrite (FeS2) prepared in Example 8 to achieve a pyrite (FeS2) concentration of 0.5 g / L in the TCE aqueous solution; allowing the solution to stand anaerobically in the dark for 24 h (reaction temperature: 30 °C); then adding 0.7 mL of the DM cell suspension from Example 7 to achieve a cell OD value of 0.15 at 600 nm; adjusting the pH to 8.0; and allowing the solution to stand anaerobically in the dark for 24 h. The concentration of TCE in the supernatant is analyzed, and the TCE degradation rate is calculated.

[0119] Example 27

[0120] A TCE degradation method is basically the same as that in Example 26, except that "pyrite (FeS2) prepared in Example 8" is replaced with "biochar aerogel (CA) prepared in Example 9".

[0121] Example 28

[0122] A TCE degradation method is basically the same as that in Example 26, except that "pyrite (FeS2) prepared in Example 8" is replaced with "pyrite composite material supported by biochar aerogel prepared in Example 13".

[0123] After the experiment, in addition to measuring the concentration of TCE in the product and calculating the TCE removal rate, Figure 8Furthermore, the concentrations of intermediate products in the reaction systems of Examples 22, 28, and 25 were tested, including cis-1,2-dichloroethylene, monochloroethylene, acetylene, ethylene, and ethane, as shown in Table 1. If cis-1,2-dichloroethylene and monochloroethylene were not detected in the products, it could be considered that complete degradation of TCE had been achieved (it should be noted in Table 1 that the sum of the intermediate product concentrations is not entirely equal to the concentration of TCE removed, because this study mainly tested TCE and intermediate products in the solution and gas phases of the reaction system, and some TCE and intermediate products were adsorbed on the material surface. From the perspective of pollution remediation, the concentration of pollutants in the liquid and gas phases of the system is mainly used as the main judgment criterion).

[0124] Table 1. Effect of the order of addition of DM cell suspension and adsorbent on TCE degradation products.

[0125]

[0126]

[0127] like Figure 8 As shown, although DM cell suspension in CA or FeS2-Fe 0 Growth was good in the presence of @CA. However, when the adsorbent and DM cell suspension were added to the TCE aqueous solution at the same time, the high toxicity of TCE to the DM cell suspension may reduce the microbial dechlorination capacity of the DM cell suspension. Therefore, the removal rate of TCE by adding both at the same time was only 76.5%, and complete degradation of TCE could not be achieved (as shown by the product concentration in Table 1).

[0128] The results of Examples 26-28 show that the highest TCE removal rate, reaching 86.7%, was achieved by reacting with the adsorbent for 24 hours first, followed by reacting with the DM cell suspension for 24 hours. This indicates that the adsorbent first degrades the high concentration of TCE, thereby reducing the high toxicity of TCE to the DM cell suspension. The subsequent addition of the DM cell suspension can achieve efficient removal of TCE and is more conducive to the complete degradation of TCE (as shown in Table 1 for product concentrations).

[0129] In contrast, the group that added DM cell suspension first and then adsorbent (Examples 23-25) had the lowest TCE removal rate (maximum 66.1%), further confirming the toxicity of high concentrations of TCE to DM cell suspension, which weakened its ability to degrade TCE. Adding adsorbent after 24 hours could not enhance the synergistic effect of the two.

[0130] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a biochar aerogel-supported pyrite composite material, characterized in that, Includes the following steps: Step 1: Mix pyrite, biochar aerogel, zero-valent iron and water, and sonicate until uniformly dispersed to obtain a first solution. The ratio of pyrite, biochar aerogel and zero-valent iron by mass is (0.5~1.5):(0.5~2):(0.5~1). Step 2: Mix vitamin C and the first solution, allow to stand at 60-65 °C for 12-12.5 h, wash, and dry to obtain a biochar aerogel-supported pyrite composite material. The ratio of vitamin C to biochar aerogel by mass is (2.5-5):(0.5-1). The method for preparing the biochar aerogel is as follows: Mix KOH, NH4Cl, Na2S·9H2O, and water, stir until homogeneous to obtain solution A. Mix rhamnolipid with solution A, stir and react at 0-5 °C for 2-2.5 h, dry to obtain a biochar aerogel precursor, and carbonize the biochar aerogel precursor at 800-805 °C for 2-2.5 h under a nitrogen atmosphere. h, wash until neutral to obtain biochar aerogel, wherein, by mass parts, the ratio of KOH, NH4Cl and Na2S·9H2O is (1~2):(2~4):(1~2), and by mass parts, the ratio of KOH and rhamnolipid is (6.25~12.5):(5~10).

2. The biochar aerogel-supported pyrite composite material obtained by the preparation method described in claim 1.

3. The application of the biochar aerogel-supported pyrite composite material as described in claim 2 with the synergistic degradation of trichloroethylene by microorganisms.

4. The application according to claim 3, characterized in that, The temperature at which the biochar aerogel-supported pyrite composite material and microorganisms synergistically degrade trichloroethylene is 25~30℃.

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