CuFeCo-LDH / BC catalyst, preparation method thereof and application of CuFeCo-LDH / BC catalyst in degradation of sulfamethoxazole-containing sewage

Abstract

The invention discloses a CuFeCo-LDH / BC catalyst, which is prepared from CuFeCo-LDH and biochar, and the biochar is uniformly distributed on the surface of the CuFeCo-LDH; the CuFeCo-LDH is prepared by taking a solution A and a solution B as raw materials and adopting a coprecipitation reaction; the solution A is a mixed aqueous solution of Cu < 2 + >, Co < 2 + > and Fe < 3 + >, and the solution B is a mixed aqueous solution of OH <-> and CO3 < 2->. The CuFeCo-LDH / BC catalyst promotes the generation of various active species under the synergistic effect of peroxydisulfate or peroxymonosulfate activation, metal redox cycle and biochar, so that SMX is thoroughly degraded. And meanwhile, the CuFeCo-LDH / BC catalyst has universality on degradation of the antibiotics. The invention also discloses an application of the CuFeCo-LDH / BC catalyst in degradation of sewage containing antibiotics.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of green catalysis and environmental chemistry, and relates to a CuFeCo-LDH / BC catalyst, a preparation method thereof and application of the catalyst in degradation of sulfamethoxazole-containing wastewater. BACKGROUND

[0002] Sulfamethoxazole (SMX) is a widely used antibiotic that enters water bodies through excretion due to its low absorption rate in the human body. Sulfamethoxazole poses a serious threat to ecological safety and human health due to its low biodegradability, environmental persistence and drug resistance-inducing properties. Traditional water treatment technologies have limited removal efficiency of SMX, and it is urgent to develop efficient and environmentally friendly degradation methods. Advanced oxidation processes based on peroxymonosulfate (PS) or peroxodisulfate (SPS) activation exhibit significant potential in the treatment of refractory organic pollutants by generating highly active oxygen species (such as SO4· - , ·OH, ·O2 - and · 1 O2). Existing peroxymonosulfate (SPS) or peroxodisulfate (PS) activation strategies include homogeneous transition metal catalysis (such as Fe 2+ , Co 2+ ) and heterogeneous catalysis (such as carbon materials and metal oxides), but the homogeneous system has the risk of secondary pollution caused by metal ion leaching, so the heterogeneous activation technology is more concerned.

[0003] In recent years, the conversion of biomass waste into biochar (BC) based catalysts has become a research hotspot. BC is prepared by pyrolysis of biomass, and it can not only enhance the adsorption of pollutants, but also act as a carrier to inhibit the agglomeration of nanoparticles due to its high specific surface area, porous structure and rich surface functional groups. In addition, BC itself has the ability to activate PS to generate active oxygen, which conforms to the concept of waste resource utilization.

[0004] Therefore, if CuFeCo-LDH and BC can be prepared into a composite catalyst, the defects such as poor dispersion and interface combination of heterojunction materials, easy leaching of metal active sites and difficulty in structural synergistic optimization can be overcome. SUMMARY

[0005] The application aims to solve the problem of low removal rate of sulfamethoxazole and other antibiotics in the prior art, and provides a CuFeCo-LDH / BC catalyst and a preparation method thereof. The application realizes uniform loading of biochar (BC) on CuFeCo-LDH by using an in-situ growth method, which strengthens the interface combination, optimizes the stability of metal components and inhibits leaching, and successfully constructs a highly efficient and stable CuFeCo-LDH / BC catalyst. The CuFeCo-LDH / BC catalyst has both oxidation function and large specific surface area, and can be used for peroxymonosulfate (PS) or peroxodisulfate (SPS) activation, metal redox cycle (Mn+ / M (n-1)+ ) and BC, promote the generation of ·OH, SO4·-, 1O2 and ·O 2- and other active species, and further degrade SMX. Meanwhile, the CuFeCo-LDH / BC catalyst has universality for antibiotic degradation.

[0006] To achieve the above object, the application adopts the following technical scheme:

[0007] A CuFeCo-LDH / BC catalyst, the CuFeCo-LDH / BC catalyst comprises CuFeCo-LDH and biochar (BC), and the biochar is uniformly distributed on the surface of the CuFeCo-LDH; the CuFeCo-LDH is prepared by using solution A and solution B as raw materials through a coprecipitation reaction; wherein the solution A is a mixed aqueous solution of Cu 2+ , Co 2+ and Fe 3+ , the solution B is a mixed aqueous solution of OH - and CO3 2- ; the ratio of the sum of the amounts of substances of Cu 2+ and Co 2+ to the amount of substance of Fe 3+ is 1:1-3:1; and the ratio of the amounts of substances of Cu 2+ and Co 2+ is 1:1-3:1.

[0008] The CuFeCo-LDH is prepared by the following method, comprising: simultaneously adding the solution A and the solution B into deionized water to perform a coprecipitation reaction, after the addition is completed, aging is performed, then the precipitate is separated out, and the precipitate is washed and dried to obtain the CuFeCo-LDH.

[0009] Preferably, the ratio of the sum of the amounts of substances of Cu 2+ and Co 2+ to the amount of substance of Fe 3+ is 1:1-2:1.

[0010] Most preferably, the ratio of the sum of the amounts of substances of Cu 2+ and Co 2+ to the amount of substance of Fe 3+ is 2:1.

[0011] Preferably, the ratio of the amounts of substances of Cu 2+ and Co 2+ is 3:1.

[0012] The Cu 2+ is prepared from Cu2+ provided by a nitrate or acetate of Co 2+ 2+ provided by a nitrate or acetate of Fe 3+ 3+ provided by a nitrate or acetate of Fe

[0013] Specifically, the nitrate of Cu 2+ is copper nitrate or copper nitrate trihydrate, the acetate of Cu 2+ is copper acetate or copper acetate monohydrate; the nitrate of Co 2+ is cobalt nitrate or cobalt nitrate nonahydrate, the acetate of Co 2+ is cobalt acetate or cobalt acetate tetrahydrate; the nitrate of Fe 3+ is iron nitrate or iron nitrate nonahydrate, the acetate of Fe 3+ is iron acetate or iron acetate tetrahydrate.

[0014] The CO3 2- is derived from Na2CO3, OH - is derived from NaOH.

[0015] Preferably, the amount of substance of CO3 2- and the amount of substance of OH - respectively satisfy:

[0016]

[0017] wherein, is the sum of the amount of substance of Cu 2+ and Co 2+ ; and is the amount of substance of Fe 3+ .

[0018] The biochar (BC) is prepared by mixing a raw material and NaOH solid in a mass ratio of 1:1 to 2:1, and calcining the mixture at 500-650°C for 2-6h under a nitrogen atmosphere.

[0019] NaOH plays a role of an activator and pore-forming agent in the preparation of the biochar, and can increase the specific surface area of the biochar. Preferably, the mass ratio of the raw material to NaOH is 1:1.

[0020] ​​​​When molasses is used as a raw material to prepare biochar, the method includes: drying the molasses at 120° C. to obtain a solid, grinding the solid, and passing it through a 100-mesh sieve to obtain a powder; mixing the powder with NaOH solid in a mass ratio of 1:1 to 2:1, and calcining the mixture at 500 to 650° C. for 2 to 6 hours under a nitrogen atmosphere to obtain the biochar.

[0021] The molasses contains 24-36% sucrose and 12-24% other types of sugar. In addition, the molasses contains 3-4% soluble colloids, which are mainly xylan, arabic gum and pectin.

[0022] The mass ratio of the CuFeCo-LDH to the biochar is 1:1 to 10:1.

[0023] Preferably, the mass ratio of the CuFeCo-LDH to biochar is 7:1 to 10:1.

[0024] The present invention can adjust the ratio of CuFeCo-LDH to biochar, and specifically, the mass ratio of CuFeCo-LDH to biochar can be adjusted to 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10.

[0025] Most preferably, the mass ratio of CuFeCo-LDH to biochar is 10:1.

[0026] Another object of the present invention is to provide a method for preparing the CuFeCo-LDH / BC catalyst, comprising the following steps:

[0027] Step (1), adding solution A and solution B dropwise to deionized water simultaneously for co-precipitation reaction, aging after the addition is completed, separating the precipitate, washing and drying the precipitate to obtain CuFeCo-LDH;

[0028] Step (2), dispersing CuFeCo-LDH and biochar in deionized water, stirring at room temperature, centrifuging, washing, and drying to obtain a CuFeCo-LDH / BC catalyst.

[0029] In step (1), the solution A is Cu 2+ 、Co 2+ and Fe 3+ of a mixed aqueous solution.

[0030] The solution B is CO3 2- and OH - of a mixed aqueous solution.

[0031] The temperature of the coprecipitation reaction is 55-65°C.

[0032] The pH of the co-precipitation reaction is 9-10.

[0033] The temperature of the aging is 60℃.

[0034] The time of the aging is 12h.

[0035] The solvent used in the washing is deionized water; the end point of the washing is that the precipitate is washed with deionized water until the pH of the filtrate is 7.

[0036] The temperature of the drying is 105℃, and the time of the drying is 24h.

[0037] In step (2), the time of the stirring is 12-30h, preferably 24h.

[0038] The solvent used in the washing is deionized water; the end point of the washing is that the precipitate is washed with deionized water until the pH of the filtrate is 7.

[0039] The drying mode is oven drying or freeze drying; the temperature of the oven drying is 105℃, and the time of the oven drying is 24h.

[0040] Another object of the present application is to provide the use of the CuFeCo-LDH / BC catalyst in degrading sewage containing antibiotics.

[0041] The use comprises mixing the CuFeCo-LDH / BC catalyst with the sewage containing antibiotics and an oxidizing agent to perform an oxidative degradation reaction.

[0042] The antibiotic is sulfamethoxazole, tetracycline hydrochloride, ciprofloxacin, cefalexin or amoxicillin.

[0043] The oxidizing agent is sodium peroxymonosulfate or sodium peroxodisulfate; preferably, the oxidizing agent is sodium peroxodisulfate.

[0044] The ratio of the use amount of the oxidizing agent to the sewage containing antibiotics is 0.1-0.5g / L, preferably 0.35g / L.

[0045] The ratio of the use amount of the CuFeCo-LDH / BC catalyst to the sewage containing antibiotics is 0.1-0.4g / L, preferably 0.25g / L.

[0046] The temperature of the oxidative degradation reaction is room temperature.

[0047] The time of the oxidative degradation reaction is 10-150min.

[0048] Specifically, when the antibiotic is sulfamethoxazole, the time of the oxidative degradation reaction is 10-150min, preferably 60-90min, and most preferably 60min.

[0049] The oxidative degradation reaction is carried out under stirring conditions. Preferably, the stirring speed is 300-800 r / min, wherein the optimal stirring speed is 450 r / min.

[0050] The beneficial effects of the present invention are:

[0051] (1) The CuFeCo-LDH / BC catalyst of the present invention is a composite material composed of hydrotalcite CuFeCo-LDH and biochar. The main active component of the catalyst of the present invention is Cu 2+ , Cu 2+ with Fe 3+ 、Co 2+ The ternary metal layered double hydroxide CuFeCo-LDH connects Fe 2+ 、Co 2+ 、Cu 2+ The active components are fixed on the cationic plate layer, and will not be lost due to falling off or dissolution. It not only plays the role of oxidative degradation, but also eliminates the secondary pollution caused by leaching and dissolution of metal cations. Moreover, the catalyst is recyclable, which greatly saves the cost of raw materials and has certain industrial practical value.

[0052] (2) The preparation of the CuFeCo-LDH / BC catalyst of the present invention is simple, the process is green and environmentally friendly, and the raw materials are cheap, with high atom economic benefits.

[0053] (3) When the CuFeCo-LDH / BC catalyst of the present invention activates sodium persulfate (SPS) to oxidatively degrade antibiotics such as sulfamethoxazole, sodium persulfate and ·OH, SO4·-, 1O2 and ·O 2- The catalyst exhibits excellent degradation performance against antibiotics through synergistic effects of active species such as sulfamethoxazole and chlorinated ...

[0054] (4) Sodium persulfate activated CuFeCo-LDH / BC to degrade SMX wastewater, and the toxicity of the water was significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 These are SEM images of BC, CuFeCo-LDH and CuFeCo-LDH / BC catalysts prepared in Example 1.

[0056] Figure 2 These are the XRD patterns of the CuFeCo-LDH / BC catalysts with different biochar contents prepared in Examples 1, 4, and 6.

[0057] Figure 3FT-IR images of CuFeCo-LDH / BC catalysts with different biochar contents prepared in Examples 1, 4, and 6.

[0058] Figure 4 These are the adsorption-desorption curves and pore size distribution diagrams of different catalysts prepared in Examples 1, 4, and 6.

[0059] Figure 5 This is the mechanism diagram of sodium persulfate activation of CuFeCo-LDH / BC for degradation of SMX wastewater.

[0060] Figure 6 Ecological structure activity relationship (ECOSAR) software was used to analyze the toxicity of SMX and its main degradation products during the degradation of SMX by CuFeCo-LDH / BC@SPS system with respect to: (a) LC50 of fathead minnow (96 h), (b) LC50 of Tetrahymena piriformis (48 h), (c) oral LC50 of rats, (d) bioaccumulation coefficient, (e) developmental toxicity and (f) mutagenicity of SMX and its degradation intermediates. DETAILED DESCRIPTION

[0061] The technical solutions of the present invention are described in more detail below with reference to the embodiments, but these embodiments do not limit the protection scope of the present invention.

[0062] Example 1

[0063] Weigh 6.0g of molasses, which contains 35% sucrose and 18% other types of sugar. In addition, it contains 4% soluble colloids, mainly xylan, arabinan, and pectin, and the rest is water. Place it in a ceramic crucible and dry it in an oven at 120°C for 24 hours to remove free water and intermolecular water to obtain a solid. The solid is ground and passed through a 100-mesh sieve (pore size 0.15mm) to obtain a uniform powder for later use. Weigh 3.0g of the powder, mix it with 3g of NaOH, place it in a tube furnace, heat it to 500°C under an N2 atmosphere, keep it warm for 4 hours, cool it to room temperature, wash it with deionized water until it is neutral, place it in an oven at 105°C for 12 hours, and grind it to obtain biochar (BC).

[0064] The SEM images of the prepared BC are shown in Figure 2. Figure 1 As shown in a, it can be seen that the biochar has abundant pores and presents a honeycomb structure.

[0065] According to the molar ratio of the metal element copper (Cu) to cobalt (Co) is 3:1, the total amount of Cu and Co to the molar ratio of Fe element is 2:1, 7.24g Cu (NO3) 2·3H2O, 2.49g Co (CH3COO) 2·4H2O, 8.08g Fe (NO3) 3·9H2O are weighed, the three kinds of metal salts are dissolved in 100mL deionized water to prepare a mixed salt solution, which is recorded as solution A.

[0066] According to the formula The amount of NaOH and Na2CO3 is calculated as 3.84g and 4.24g respectively; 3.84g NaOH and 4.24g Na2CO3 are dissolved in 60mL deionized water to prepare a mixed alkali solution, which is recorded as solution B.

[0067] About 10mL deionized water is pre-added in a three-necked flask and heated to 60℃, and solutions A and B are simultaneously added to the flask under stirring, the pH of the mixed solution is kept at 9-10 during the dropwise addition process, after the dropwise addition is completed, the solution is aged at 60℃ under stirring for 12h, filtered, the filter cake is washed with deionized water until the pH of the filtrate is 7, and dried in an oven at 105℃ for 24h to obtain a hydrotalcite CuFeCo-LDH, which is ground into a powder for use.

[0068] 2.0g CuFeCo-LDH and 0.2g biochar are dispersed in 20mL deionized water, stirred at room temperature for 24h; centrifuged, washed with deionized water until the pH of the filtrate is 7, and dried at 105℃ for 24h to obtain a 10CuFeCo-LDH / BC catalyst.

[0069] The SEM images of CuFeCo-LDH and 10CuFeCo-LDH / BC are shown in Figure 1 b of FIG. 1, Figure 1 c of FIG. 1, it can be seen that the hydrotalcite CuFeCo-LDH presents an ultra-thin nanosheet structure and belongs to a layered hydroxide; the CuFeCo-LDH / BC has many bioactive carbon BC adsorbed on the surface of the LDH sheet layer.

[0070] The XRD patterns of CuFeCo-LDH and 10CuFeCo-LDH / BC are shown in Figure 2 It can be seen that the diffraction peaks of the XRD patterns of CuFeCo-LDH and 10CuFeCo-LDH / BC all show characteristic peaks of hydrotalcite, which is due to the uniform distribution of BC on the surface of the hydrotalcite.

[0071] The FT-IR patterns of CuFeCo-LDH and 10CuFeCo-LDH / BC are shown in Figure 3 It can be seen that the characteristic peaks of the FT-IR spectra of CuFeCo-LDH and 10CuFeCo-LDH / BC are at 3437cm-1, 1630cm-1, 1380cm-1, 1080cm-1, 800cm-1, 600cm-1, 450cm-1, 400cm-1, 350cm-1, 300cm-1, 200cm-1, 100cm-1, 80cm-1, 60cm-1, 40cm-1, 20cm-1, 10cm-1, which are the characteristic peaks of the hydrotalcite.-1 , 1634 cm -1 -1 -1 -1 -1 -1

[0072] Figure 4 Figure 4

[0073] Catalyst performance evaluation: BC, CuFeCo-LDH, 10CuFeCo-LDH / BC dosage was 0.25 g / L; 500 mL concentration of 20 mg / L sulfamethoxazole solution (prepared with deionized water), it is added to the reaction vessel, first add 0.25 g / L catalyst (i.e. 1 L sulfamethoxazole solution added 0.25 g catalyst), then add 0.35 g / L sodium peroxodisulfate (i.e. 1 L sulfamethoxazole solution added 0.35 g sodium peroxodisulfate), using 1 M sodium hydroxide aqueous solution or 1 M sulfuric acid to adjust the pH of the solution to 6. At room temperature, with a stirring speed of 450 r / min, the reaction was carried out for 60 min. After the reaction, 3 mL sample was taken, filtered with 0.45 μm organic filter membrane, then mixed with 50% (V / V) ethanol water (absolute ethanol and deionized water according to the volume ratio of 1:1) in equal volume, put into the sample injection bottle, the content of sulfamethoxazole in the sample was detected by gas chromatography, the degradation rate of BC, CuFeCo-LDH, 10CuFeCo-LDH / BC to sulfamethoxazole was calculated to be 30.82%, 62.97%, 99.74% respectively. The above three catalysts were reused for 10 times, the degradation rate of sulfamethoxazole was 29.3%, 61.7%, 97.9% respectively, it can be seen that the activity of 10CuFeCo-LDH / BC catalyst did not decrease significantly.​​​​​​​​​

[0074] The catalytic mechanism of CuFeCo-LDH / BC catalyst for catalytic degradation of sulfamethoxazole antibiotic is:

[0075] The possible catalytic mechanism of CuFeCo-LDH / BC for degrading sulfamethoxazole under the oxidation of sodium persulfate is shown in Figure 4 Firstly, sodium persulfate (SPS) can be activated by partially charged ions to generate SO4 ·- , and the metal active sites (Co / Fe / Cu) are oxidized to M (n+1)+ (formula (1)). At the same time, electrons are transferred to SPS to generate SO4 ·- , which is rapidly hydrolyzed to ·OH (formula (2)). In addition, the formed M (n+1)+ may be reduced to M n+ (formula (3)) by SPS, biochar and H2O2. The metal valence cycle drives the redox reaction and maintains the catalytic activity. The generated SO4 ·- may induce the production of ·OH and H2O2 through a free radical chain reaction (formula (4)). ·O2 - and 1 O2path: ·OH reacts with H2O2 to generate superoxide anion radical (HO2 · ) (formula (5). In turn, ·O2 - (formula (6)) is induced. The latter participates in the degradation through rapid electron transfer; ·O2 - recombination can generate sufficient singlet oxygen ( 1 O2) (formula (7), (8)). Summary: In this system, active oxygen species (·OH, SO4 ·- , ·O2 - and 1 O2) and metal redox synergistically work together to achieve rapid degradation of pollutants (formula (9)). The metal redox cycle and the multi-path free radical generation together guarantee the high efficiency and stability of the CuFeCo-LDH / BC@SPS system.

[0076] M n+ +S2O8 2- →M (n+1)+ +SO4 ·- +SO4 2- (1)

[0077] SO4 ·- +H2O→SO4 2- +·OH+H + (2)

[0078] M (n+1)+ +S2O8 2- →Mn+ +S2O8 ·-

[0079] M (n+1)+ +biochar - →M n+ +biochar (3)

[0080] M (n+1)+ +H2O2+2OH - →M n+ + O2 - +2H2O

[0081] 2·OH→H2O2 (4)

[0082] OH+H2O2→HO2 · +H2O (5)

[0083] HO2 · →H + + O2 - (6)

[0084] 2.O2 - +2H2O→H2O2+2OH - +2 1 O2 (7)

[0085] O2 - +·OH→OH - + 1 O2 (8)

[0086] 1 O2 / ·OH / SO4 ·- / ·O2 - +SMX→intermediates→CO2+H2O (9)

[0087] Toxicity analysis of SMX and its main degradation products during the degradation of SMX by 10CuFeCo-LDH / BC@SPS system is shown in Figure 6 , where P1 represents sulfamethoxazole (SMX), and P2-P11 are intermediate products of SMX degradation for 20 min, respectively. Their structures are shown below:

[0088]

[0089]

[0090] The toxicity estimation software tool (TEST) was used to comprehensively evaluate the acute and chronic toxicity of SMX and its intermediates. Figure 6(a) As shown, the LC50 of blackhead minnow 96h SMX was 2.75 mg / L, which could be considered as toxic. Nevertheless, P2 of blackhead minnow containing LC50 was extremely toxic, and the toxicity of subsequent oxidation intermediates was all harmless products. The acute toxicity (characterized by LC50) of degradation intermediates was mostly lower than SMX, of which the rest was classified as harmless substances except for product P2. This result showed that the degradation process of SMX could effectively reduce the direct ecological risk of pollutants, but further assessment of long-term environmental effects was still needed in combination with its chronic toxicity and bioaccumulation characteristics. Figure 6 (b) As shown, the 48h half maximal inhibitory concentration (IGC50) of SMX on Tetrahymena pyriformis was 6.09 mg / L, indicating that it was toxic, and the toxicity of subsequent oxidation intermediates was reduced. It could pose a greater threat to Tetrahymena populations, and careful control was needed in practical applications. According to the QSAR model, the higher the oral LD50 value in rats, the lower the acute toxicity of the substance. From Figure 6 (c) As can be seen, the acute toxicity (LD50) of SMX and most intermediates was more than 2000 mg / kg, which was classified as "not very toxic". In addition, the bioaccumulation factors of each intermediate product were small and lower than SMX Figure 6 (d)), indicating that they were not easy to accumulate and enrich in the environment. Developmental toxicity and mutagenicity showed a clear downward trend Figure 6 (e) and (f)). In addition, the toxicity of intermediates would degrade over time, gradually reducing their toxicity. Therefore, the 10CuFeCo-LDH / BC@SPS system could effectively reduce the toxicity of SMX and reduce the related ecological risk.

[0091] Example 2

[0092] BC was prepared as in Example 1.

[0093] CuFeCo-LDH was prepared as in Example 1, with the only difference being that the molar ratio of metal elements Cu to Co was 2:1.

[0094] According to the molar ratio of metal elements Cu to Co being 2:1 and the molar ratio of the total amount of Cu and Co elements to Fe element being 2:1, 6.44 g of Cu(NO3)2·3H2O, 3.32 g of Co(CH3COO)2·4H2O, and 8.08 g of Fe(NO3)3·9H2O were weighed, and the three kinds of metal salts were dissolved in 100 mL of deionized water to prepare a mixed salt solution, which was denoted as solution A.

[0095] According to the formula The amount of NaOH and Na2CO3 was calculated to be 3.84 g and 4.24 g, respectively, and 3.84 g of NaOH and 4.24 g of Na2CO3 were dissolved in 60 mL of deionized water to prepare a mixed alkali solution, which was denoted as solution B.

[0096] Pre-adding about 10 mL deionized water in a three-neck flask, heating to 60 ℃, adding solution A and B into the flask simultaneously under stirring, keeping the pH of the mixture = 9-10 during the whole process of dropping, after the dropping process, aging for 12 h under stirring at 60 ℃, filtering, washing the filter cake with deionized water until the pH of the filtrate = 7, drying in an oven at 105 ℃ for 24 h to obtain CuFeCo-LDH, and grinding it into powder for use.

[0097] Dispersing 2.0 g CuFeCo-LDH and 0.2 biochar in 20 mL deionized water, stirring for 24 h at room temperature. Centrifuging, washing with deionized water until the pH of the filtrate = 7, drying at 105 ℃ for 24 h to obtain 10CuFeCo-LDH / BC-1 catalyst.

[0098] The performance evaluation of the catalyst is the same as that in Example 1, and the degradation rate of sulfamethoxazole is 93.20%.

[0099] Example 3

[0100] The preparation of BC is the same as that in Example 1.

[0101] The preparation of CuFeCo-LDH is the same as that in Example 1, except that the molar ratio of metal elements Cu to Co is 1:1.

[0102] According to the molar ratio of metal elements Cu to Co being 1:1 and the molar ratio of the total amount of Cu and Co elements to Fe element being 2:1, 4.83 g Cu(NO3)2·3H2O, 4.98 g Co(CH3COO)2·4H2O and 8.08 g Fe(NO3)3·9H2O are weighed, and the three kinds of metal salts are dissolved in 100 mL deionized water to prepare a mixed salt solution, which is recorded as solution A.

[0103] According to the formula The amount of NaOH and Na2CO3 is calculated to be 3.84 g and 4.24 g respectively, 3.84 g NaOH and 4.24 g Na2CO3 are dissolved in 60 mL deionized water to prepare a mixed alkali solution, which is recorded as solution B.

[0104] Pre-adding about 10 mL deionized water in a three-neck flask, heating to 60 ℃, adding solution A and B into the flask simultaneously under stirring, keeping the pH of the mixture = 9-10 during the whole process of dropping, after the dropping process, aging for 12 h under stirring at 60 ℃, filtering, washing the filter cake with deionized water until the pH of the filtrate = 7, drying in an oven at 105 ℃ for 24 h to obtain CuFeCo-LDH, and grinding it into powder for use.

[0105] 2.0 g CuFeCo-LDH and 0.2 biochar were dispersed in 20 mL deionized water, stirred at room temperature for 24 h. Centrifugation, deionized water washing until the filtrate pH = 7, 105 ℃ drying for 24 h, to obtain 10CuFeCo-LDH / BC-2 catalyst.

[0106] The performance evaluation of the catalyst was the same as in Example 1, and the degradation rate of sulfamethoxazole was 90.56%.

[0107] Example 4

[0108] The preparation of BC was the same as in Example 1.

[0109] The preparation of CuFeCo-LDH was the same as in Example 1, except that the molar ratio of the total amount of Cu and Co elements to Fe element was 3:1.

[0110] According to the molar ratio of metal elements Cu to Co being 3:1 and the molar ratio of the total amount of Cu and Co elements to Fe element being 3:1, 10.87 g of Cu(NO3)2·3H2O, 3.74 g of Co(CH3COO)2·4H2O, and 8.08 g of Fe(NO3)3·9H2O were weighed, and the three kinds of metal salts were dissolved in 100 mL of deionized water to prepare a mixed salt solution, which was denoted as solution A.

[0111] According to the formula The amounts of NaOH and Na2CO3 were calculated to be 5.12 g and 4.24 g, respectively, and 5.12 g of NaOH and 4.24 g of Na2CO3 were dissolved in 60 mL of deionized water to prepare a mixed alkali solution, which was denoted as solution B.

[0112] About 10 mL of deionized water was pre-added to a three-necked flask and heated to 60 ℃, and solutions A and B were simultaneously added to the flask under stirring, and the pH of the mixed solution was maintained at 9-10 during the whole process of dropwise addition. After the dropwise addition was completed, the mixture was aged at 60 ℃ for 12 h under stirring, filtered, and the filter cake was washed with deionized water until the filtrate pH = 7. The CuFeCo-LDH was obtained by drying in an oven at 105 ℃ for 24 h, and then ground into a powder for use.

[0113] 2.0 g CuFeCo-LDH and 0.2 biochar were dispersed in 20 mL deionized water, stirred at room temperature for 24 h. Centrifugation, deionized water washing until the filtrate pH = 7, 105 ℃ drying for 24 h, to obtain 10CuFeCo-LDH / BC-2 catalyst.

[0114] The performance evaluation of the catalyst was the same as in Example 1, and the degradation rate of sulfamethoxazole was 79.8%.

[0115] Example 5

[0116] BC was prepared as in Example 1.

[0117] CuFeCo-LDH was prepared as in Example 1, except that the molar ratio of the total amount of Cu and Co elements to Fe element was 1:1.

[0118] According to the molar ratio of Cu element to Co element being 3:1 and the molar ratio of the total amount of Cu and Co elements to Fe element being 1:1, 3.62 g of Cu(NO3)2·3H2O, 1.25 g of Co(CH3COO)2·4H2O and 8.08 g of Fe(NO3)3·9H2O were weighed, and the three kinds of metal salts were dissolved in 100 mL of deionized water to prepare a mixed salt solution, which was recorded as solution A.

[0119] According to the formula The amounts of NaOH and Na2CO3 were calculated to be 2.56 g and 4.24 g, respectively, and 2.56 g of NaOH and 4.24 g of Na2CO3 were dissolved in 60 mL of deionized water to prepare a mixed alkali solution, which was recorded as solution B.

[0120] About 10 mL of deionized water was pre-added to a three-necked flask, which was heated to 60°C, and solutions A and B were simultaneously added to the flask under stirring, the pH of the mixed solution was kept at 9-10 during the whole process of dropwise addition, and after the dropwise addition was completed, the mixed solution was aged at 60°C for 12 h under stirring, then filtered, the filter cake was washed with deionized water until the pH of the filtrate was 7, and the filter cake was dried in an oven at 105°C for 24 h to obtain CuFeCo-LDH, which was ground into a powder for use.

[0121] 2.0 g of CuFeCo-LDH and 0.2 g of biochar were dispersed in 20 mL of deionized water, which was stirred at room temperature for 24 h, centrifuged, washed with deionized water until the pH of the filtrate was 7, and dried at 105°C for 24 h to obtain the 10CuFeCo-LDH / BC-4 catalyst.

[0122] The performance evaluation of the catalyst was the same as in Example 1, and the degradation rate of sulfamethoxazole was 87.9%.

[0123] Example 6

[0124] Only the mass ratio of CuFeCo-LDH to biochar was adjusted to be 9:1, and the rest was the same as in Example 1 to prepare the 9CuFeCo-LDH / BC catalyst.

[0125] 1.8 g of CuFeCo-LDH and 0.2 g of biochar were dispersed in 20 mL of deionized water, which was stirred at room temperature for 24 h, centrifuged, washed with deionized water until the pH of the filtrate was 7, and dried at 105°C for 24 h to obtain the 9CuFeCo-LDH / BC catalyst.

[0126] 9CuFeCo-LDH / BC XRD pattern is shown in Fig. Figure 2 , which shows the characteristic peaks of hydrotalcite. The FT-IR pattern of 9CuFeCo-LDH / BC is shown in Fig. Figure 3 , which shows the same characteristic peaks as 10CuFeCo-LDH / BC. The adsorption-desorption and pore size distribution of 9CuFeCo-LDH / BC are shown in Fig. Figure 4 a and Fig. Figure 4 b, respectively. It can be seen that according to IUPAQ classification, 9CuFeCo-LDH / BC catalyst presents type III isotherm and H3 hysteresis loop, which confirms the interstices formed by the aggregation of layered particles.

[0127] The performance evaluation of the catalyst is the same as Example 1, and the degradation rate of sulfamethoxazole is 96.3%.

[0128] Example 7

[0129] 8CuFeCo-LDH / BC catalyst is prepared by adjusting the mass ratio of CuFeCo-LDH and biochar to 8:1, and the rest is the same as Example 1.

[0130] 1.6g CuFeCo-LDH and 0.2 biochar are dispersed in 20mL deionized water, stirred at room temperature for 24h; centrifuged, washed with deionized water until the filtrate pH=7, dried at 105℃ for 24h, to obtain 8CuFeCo-LDH / BC catalyst.

[0131] The XRD pattern of 8CuFeCo-LDH / BC is shown in Fig. Figure 2 , which shows the characteristic peaks of hydrotalcite. The FT-IR pattern of 8CuFeCo-LDH / BC is shown in Fig. Figure 3 , which shows the same characteristic peaks as 10CuFeCo-LDH / BC. The adsorption-desorption and pore size distribution of 8CuFeCo-LDH / BC are shown in Fig. Figure 4 a and Fig. Figure 4 b, respectively. It can be seen that according to IUPAQ classification, 8CuFeCo-LDH / BC catalyst presents type III isotherm and H3 hysteresis loop, which confirms the interstices formed by the aggregation of layered particles.

[0132] The performance evaluation of the catalyst is the same as Example 1, and the degradation rate of sulfamethoxazole is 92.7%.

[0133] Example 8

[0134] 7CuFeCo-LDH / BC is prepared according to Example 1, except that the ratio of CuFeCo-LDH and biochar is 7:1.

[0135] 1.4 g of CuFeCo-LDH and 0.2 g of biochar were dispersed in 20 mL of deionized water. The mixture was stirred at room temperature for 24 h, centrifuged, washed with deionized water until the filtrate had a pH of 7, and dried at 105°C for 24 h to obtain a 7% CuFeCo-LDH / BC catalyst.

[0136] The XRD pattern of the prepared 7CuFeCo-LDH / BC is shown in Figure 2 , showing the characteristic peaks of hydrotalcite. The FT-IR image of the prepared 7CuFeCo-LDH / BC is shown in Figure 3 , showing the same characteristic peaks as 10CuFeCo-LDH / BC. The adsorption and desorption and pore size distribution of the prepared 7CuFeCo-LDH / BC are shown in Figure 4 a and Figure 4 As shown in Figure b, according to the IUPAQ classification, the 7CuFeCo-LDH / BC catalyst exhibits a type III isotherm and an H3-type hysteresis loop, confirming the crack-like pores formed by the aggregation of layered particles.

[0137] The performance evaluation of the catalyst was the same as in Example 1, and the degradation rate of sulfamethoxazole was 90.6%.

[0138] Example 9

[0139] Weigh 6.0 g of molasses (same as in Example 1), place it in a ceramic crucible, and place it in an oven at 120°C for 24 hours to remove free water and intermolecular water to obtain a solid. Grind the solid and pass it through a 100-mesh sieve (pore size 0.15 mm) to obtain a uniform powder for later use. Weigh 3.0 g of molasses granules, mix it with 3 g of NaOH, place it in a tube furnace, heat it to 550°C under a N2 atmosphere, and keep it warm for 5 hours. Cool it to room temperature, wash it with deionized water until it is neutral, place it in an oven at 105°C for 12 hours, and grind it to obtain biochar (BC).

[0140] The method for preparing 10CuFeCo-LDH / BC catalysts was referred to in Example 1, except that the biochar in Example 1 was replaced with the biochar of this example to prepare CuFeCo-LDH / BC catalysts.

[0141] The performance evaluation of the catalyst was the same as in Example 1, and the degradation rate of sulfamethoxazole was 93.7%.

[0142] Example 10

[0143] Catalyst performance evaluation: 500 mL of different antibiotic (tetracycline hydrochloride, ciprofloxacin, ampicillin, amoxicillin, sulfamethoxazole) solutions (prepared with deionized water) with a concentration of 300 mg / L were treated with the 10CuFeCo-LDH / BC catalyst prepared in Example 1, the catalyst was added in an amount of 0.25 g / L, and the sodium peroxodisulfate was added in an amount of 0.35 g / L, the reaction temperature was 25°C, and the stirring speed was 450 r / min. After the reaction was completed, samples were taken and analyzed to obtain the degradation rates of different antibiotics.

[0144] Table 1. Degradation effect of CuFeCo-LDH / BC catalyst on different antibiotic solutions

[0145]

[0146] As can be seen from Table 1, the 10CuFeCo-LDH / BC catalyst prepared in Example 1 can well activate the persulfate to degrade antibiotics, indicating that the catalyst has potential industrial application value in degrading antibiotics.

[0147] Comparative Example 1

[0148] CuCo-LDH / BC, CoFe-LDH / BC and CuFe-LDH / BC were prepared according to Example 1.

[0149] CuCo-LDH / BC: CuCo-LDH / BC is composed of CuCo-LDH and biochar (BC), and the biochar is uniformly distributed on the surface of CuCo-LDH.

[0150] CuCo-LDH was prepared by coprecipitation: first, 2.42 g of Cu(NO3)2·3H2O and 2.91 g of Co(NO3)2·6H2O were weighed according to a molar ratio of copper (Cu) to cobalt (Co) of 1:1, and the two kinds of metal salts were dissolved in 100 mL of deionized water to prepare solution A;

[0151] The amount of NaOH was calculated according to the charge balance formula:

[0152]

[0153] The amount of NaOH was 1.28 g, which was dissolved in 60 mL of deionized water to prepare solution B.

[0154] 10 mL of deionized water was added to a three-necked flask and preheated to 60°C, and solutions A and B were simultaneously added to the flask under continuous stirring, and the dropping speed was controlled to maintain the pH of the system at 9-10; after the addition was completed, the system was aged at 60°C for 12 h, cooled, vacuum filtered, and the precipitate was washed with deionized water until the pH of the filtrate was 7, and then dried at 105°C for 24 h to obtain a powder of CuCo-LDH.

[0155] 2.0 g CuCo-LDH and 0.2 g biochar (BC, same as Example 1) were dispersed in 20 mL deionized water, ultrasonic for 10 min to make the mixture uniform, then stirred at room temperature for 24 h, centrifugal separation of the solid, the solid was washed with deionized water until the filtrate pH = 7, 60 °C vacuum drying for 12 h, to obtain CuCo-LDH / BC catalyst.

[0156] CoFe-LDH / BC: CoFe-LDH / BC is composed of CoFe-LDH and biochar (BC), and the biochar is uniformly distributed on the surface of CoFe-LDH.

[0157] CoFe-LDH was prepared by coprecipitation method: first, according to the molar ratio of cobalt (Co) to iron (Fe) 1:1, 2.47 g Co(CH3COO)2·4H2O and 4.04 g Fe(NO3)3·9H2O were weighed, and the two kinds of metal salt were dissolved in 100 mL deionized water to prepare solution A;

[0158] According to the charge balance formula, the amount of NaOH and Na2CO3 is calculated:

[0159]

[0160] The amount of NaOH is 1.28 g, and the amount of Na2CO3 is 2.12 g, which is dissolved in 60 mL deionized water to prepare solution B. 10 mL of deionized water was added to a three-necked flask and preheated to 60 °C, and solution A and B were added to the flask at the same time under continuous stirring, and the dropping speed was controlled to maintain the system pH = 9-10; after the end of dropping, it was stirred at 60 °C for 12 h, cooled, vacuum filtration, and the precipitate was washed with deionized water until the filtrate pH = 7, and dried at 105 °C for 24 h to obtain powder CoFe-LDH.

[0161] 2.0 g CoFe-LDH and 0.2 g biochar (BC, same as Example 1) were dispersed in 20 mL deionized water, ultrasonic for 10 min after mixing, room temperature stirring for 24 h, centrifugal separation of the solid and washing with deionized water until the filtrate pH = 7, 60 °C vacuum drying for 12 h, to obtain CoFe-LDH / BC catalyst.

[0162] CuFe-LDH / BC: CuFe-LDH / BC is composed of CuFe-LDH and biochar (BC), and the biochar is uniformly distributed on the surface of CuFe-LDH.

[0163] CuFe-LDH was prepared by coprecipitation method: first, according to the molar ratio of copper (Cu) to iron (Fe) 1:1, 2.42 g Cu(NO3)2·3H2O and 4.04 g Fe(NO3)3·9H2O were weighed, and the two kinds of metal salt were dissolved in 100 mL deionized water to prepare solution A;

[0164] The amount of NaOH and Na2CO3 was calculated according to the charge balance formula:

[0165]

[0166] The amount of NaOH was 1.28 g and the amount of Na2CO3 was 2.12 g, which were dissolved in 60 mL of deionized water to prepare solution B. 10 mL of deionized water was added to a three-necked flask and preheated to 60°C, and solution A and B were simultaneously added to the flask under continuous stirring, and the dropping speed was controlled to maintain the pH of the system at 9-10; after the addition was completed, the system was aged at 60°C for 12 h, and then cooled, vacuum filtered, washed with deionized water until the pH of the filtrate was 7, and dried at 105°C for 24 h to obtain CuFe-LDH powder.

[0167] 2.0 g of CuFe-LDH and 0.2 g of biochar (BC, same as in Example 1) were dispersed in 20 mL of deionized water, mixed after ultrasonic treatment for 10 min, stirred at room temperature for 24 h, and then centrifuged to separate the solid, which was washed with deionized water until the pH of the filtrate was 7, and then vacuum dried at 60°C for 12 h to obtain CuFe-LDH / BC catalyst.

[0168] Catalyst performance evaluation: The amount of catalysts CuCo-LDH / BC, CoFe-LDH / BC and CuFe-LDH / BC was 0.25 g / L, 500 mL of sulfamethoxazole solution with a concentration of 20 mg / L was taken and added to the reaction container, the catalyst was added first, then 0.30 g / L of sodium peroxydisulfate was added, and the pH of the solution was adjusted to 6 using 1 M sodium hydroxide aqueous solution or 1 M sulfuric acid. The reaction was stirred at room temperature at a speed of 450 r / min for 60 min, after the reaction was completed, 3 mL of sample was taken, filtered using a 0.45 μm organic filter membrane, mixed with 50% (V / V) ethanol water in equal volume, and placed in a sample bottle. The content of sulfamethoxazole in the sample was detected by gas chromatography, and the degradation rate of CuCo-LDH / BC, CoFe-LDH / BC and CuFe-LDH / BC on sulfamethoxazole was calculated, as shown in Table 2.

[0169] Table 2. Effect of different catalytic materials on catalytic degradation of sulfamethoxazole

[0170]

[0171] As can be seen from Table 2, CuCo-LDH / BC has the best catalytic degradation effect on sulfamethoxazole, which is due to the synergistic effect of Cu and Fe elements in the binary hydrotalcite. Since the degradation rate of CuCo-LDH / BC on sulfamethoxazole is higher than that of CoFe-LDH / BC, it is analyzed that Cu is the element that contributes the most in the process of degrading sulfamethoxazole.

Claims

1. A CuFeCo-LDH / BC catalyst, characterized in that: The CuFeCo-LDH / BC catalyst comprises CuFeCo-LDH and biochar, and the biochar is evenly distributed on the surface of CuFeCo-LDH; the CuFeCo-LDH is prepared by coprecipitation reaction using solution A and solution B as raw materials; wherein, the solution A is Cu 2+ 、Co 2+ and Fe 3+ A mixed aqueous solution, wherein the solution B is OH - and CO3 2- A mixed aqueous solution of Cu 2+ and Co 2+ The sum of the amount of substance and Fe 3+ The amount of substance ratio is 1:1 to 3:1; the Cu 2+ and Co 2+ The molar ratio of substances is 1:1 to 3:

1.

2. The CuFeCo-LDH / BC catalyst according to claim 1, characterized in that: The CuFeCo-LDH is prepared by the following method: solution A and solution B are simultaneously added dropwise to deionized water for coprecipitation reaction, and after the addition is completed, aging is performed, and then the precipitate is separated, and the precipitate is washed and dried to obtain CuFeCo-LDH.

3. The CuFeCo-LDH / BC catalyst according to claim 1 or 2, characterized in that: The Cu 2+ and Co 2+ The sum of the amount of substance and Fe 3+ The amount of substance ratio is 1:1 to 2:1; the Cu 2+ and Co 2+ The sum of the amount of substance and Fe 3+ The molar ratio of substances is 2:

1.

4. The CuFeCo-LDH / BC catalyst according to claim 1 or 2, characterized in that: The Cu 2+ and Co 2+ The molar ratio of substances is 3:

1.

5. The CuFeCo-LDH / BC catalyst according to claim 1 or 2, characterized in that: The Cu 2+ It is Cu 2+ The nitrate or acetate provided by the Co 2+ By Co 2+ provided by nitrate or acetate; the Fe 3+ It is made of Fe 3+ provided by nitrates or acetates; The CO3 2- Derived from Na2CO3, OH - Derived from NaOH; CO3 2- The amount of substance and OH - The amount of substance Satisfy respectively: in, Cu 2+ and Co 2+ The sum of the amounts of substances; Fe 3+ The amount of substance.

6. The CuFeCo-LDH / BC catalyst according to claim 1, characterized in that: The biochar is prepared by mixing bamboo charcoal, chestnut shell, straw, starch, glucose, cellulose or molasses with solid NaOH in a mass ratio of 1:1 to 2:1 and calcining at 500 to 650° C. for 2 to 6 hours in a nitrogen atmosphere.

7. The CuFeCo-LDH / BC catalyst according to claim 1, characterized in that: The mass ratio of CuFeCo-LDH to biochar is 1:1 to 10:1; preferably, the mass ratio of CuFeCo-LDH to biochar is 7:1 to 10:1; more preferably, the mass ratio of CuFeCo-LDH to biochar is 10:

1.

8. A method for preparing the CuFeCo-LDH / BC catalyst according to claim 1, characterized in that: The steps include: Step (1), adding solution A and solution B dropwise to deionized water simultaneously for co-precipitation reaction, aging after completion of the dropwise addition, separating the precipitate, washing and drying the precipitate to obtain CuFeCo-LDH; Step (2), dispersing CuFeCo-LDH and biochar in deionized water, stirring at room temperature, centrifuging, washing, and drying to obtain a CuFeCo-LDH / BC catalyst.

9. Use of the CuFeCo-LDH / BC catalyst according to claim 1 in degrading sewage containing antibiotics.

10. The use according to claim 9, characterized in that: include: Using the CuFeCo-LDH / BC catalyst, the sewage containing antibiotics is mixed with an oxidant to carry out an oxidative degradation reaction; Wherein, the antibiotic is sulfamethoxazole, tetracycline hydrochloride, ciprofloxacin, cephalexin or amoxicillin; The oxidant is sodium peroxymonosulfate or sodium peroxydisulfate; preferably, the oxidant is sodium peroxydisulfate; The dosage ratio of the oxidant to the sewage containing antibiotics is 0.1 to 0.5 g / L, preferably 0.35 g / L; The dosage ratio of the CuFeCo-LDH / BC catalyst to the sewage containing antibiotics is 0.1 to 0.4 g / L, preferably 0.25 g / L; The temperature of the oxidative degradation reaction is room temperature.

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