Method for treating antibiotic wastewater and eliminating biotoxicity by coupling piezoelectric catalysis with peracetic acid activation

Abstract

The invention relates to a method for treating antibiotic wastewater and eliminating biotoxicity by coupling piezoelectric catalysis with peracetic acid activation. According to the method, the CoOOH nanosheet is used as a catalyst, the piezoelectric technology is assisted, peracetic acid is synergistically activated to treat antibiotic wastewater, the surface of the CoOOH nanosheet contains rich high-catalytic-activity sites such as surface hydroxyl and oxygen vacancies, and peracetic acid can be rapidly catalyzed and activated to degrade pollutants; by introducing the piezoelectric technology, on one hand, separation of piezoelectric electrons and holes can be generated, hydroxyl generated by piezoelectric electrons and hole oxidation can further mediate activation of peracetic acid, on the other hand, ultrasonic cavitation bubble rupture can continuously excite the surface of CoOOH to generate dynamic defects in the whole reaction process, catalytic reaction active sites are increased, an oxidant is activated, and the catalytic reaction efficiency is improved. The problem that active sites on the surface of the catalyst are consumed in the catalysis process is effectively solved, and efficient and lasting pollutant removal can be achieved.

Description

Technical Field

[0001] The invention relates to a method for treating antibiotic wastewater and eliminating biological toxicity by coupling piezoelectric catalysis with peracetic acid activation, and belongs to the field of chemistry and environmental technology. Background Art

[0002] With the improvement of living and economic standards, more and more antibiotics are widely used in human production and life. However, the emergence of super bacteria means that the abuse of antibiotics will bring fatal threats to humans and organisms. With the continuous increase in the use and discharge of antibiotics, antibiotics have caused serious pollution to the environment. Compared with conventional physical and biological methods, advanced oxidation processes have the advantages of high removal rate, low cost, high mineralization rate and good safety. It is an effective method for rapid degradation of antibiotics, elimination of biological toxicity and reduction of resistance gene risks. The advanced oxidation process based on peracetic acid is a new water treatment technology that has attracted the attention of many researchers. Peracetic acid is an organic acid synthesized by acetic acid and H2O2 under the catalysis of sulfuric acid. It has the advantages of no by-products, low biological toxicity and strong oxidation ability. Peracetic acid has an OO bond similar to hydrogen peroxide and persulfate, but compared with other oxidants, it has a lower OO bond energy, is easier to be activated and broken to produce active substances to degrade pollutants, and the decomposition of peracetic acid can also provide a carbon source for subsequent biochemical treatment. Therefore, the advanced oxidation process based on peracetic acid is a pollutant removal technology with great development prospects.

[0003] So far, there are three main ways to activate peracetic acid: external energy input, homogeneous catalysis and heterogeneous catalysis. Among them, transition metal catalysts have attracted much attention due to their excellent catalytic performance, excellent stability and economic benefits. However, the intrinsic catalytic activity of heterogeneous metal catalysts for peracetic acid is low, and the active sites are easily consumed during the reaction process, which seriously hinders the development of peracetic acid-based advanced oxidation processes. At present, piezoelectric catalysis has attracted widespread research interest in wastewater treatment due to its advantages of simple operation, cleanliness and high efficiency. Similar to the photocatalytic process, under the action of external mechanical force (usually low-frequency ultrasound), piezoelectric materials will deform to generate polarization and built-in electric fields, realize the continuous separation of electrons and holes, and attract them to the opposite surface, react with water or dissolved oxygen to generate active oxygen species for wastewater treatment, and realize the conversion of mechanical energy into chemical energy. During the ultrasonic process, the high-pressure and high-temperature energy release under the rupture of cavitation bubbles, the action of microjets and shock waves, and the occurrence of cavitation processes will cause changes in the surface microstructure of metal materials and plastic deformation, prompting the catalyst to produce dynamic defects in situ and enhance the catalytic activity of the catalyst. Therefore, combining piezoelectric technology with other advanced oxidation processes will be able to provide a sustainable solution for wastewater purification. Cobalt oxyhydroxide (CoOOH), as an important intermediate substance in the conversion path of cobalt hydroxide to cobalt oxide, has great application potential in the field of high-performance heterogeneous catalysis due to its high electron transfer efficiency, high-density surface hydroxyl centers and multiple surface active sites. However, at present, cobalt oxyhydroxide (CoOOH) is mostly used as an electrode material, and CoOOH nanosheets are used as catalysts to activate peracetic acid, and piezoelectric technology is used to promote the activation of oxidants to achieve efficient generation of active oxygen species for promoting antibiotic degradation, but no research reports have been seen.

[0004] Therefore, in order to address the problems of low catalytic activity and few catalyst active sites, it is urgent to develop a new advanced oxidation technology for activating peracetic acid. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a method for treating antibiotic wastewater and eliminating biological toxicity by coupling piezoelectric catalysis with peracetic acid activation. Summary of the invention:

[0007] The present invention uses CoOOH nanosheets synthesized by a green and efficient two-step liquid phase chemical method as a catalyst, and is supplemented by piezoelectric technology to synergistically activate peracetic acid to treat antibiotic wastewater. The surface of the CoOOH nanosheet contains abundant high catalytic activity sites such as surface hydroxyl groups and oxygen vacancies, which can quickly catalyze and activate peracetic acid to degrade pollutants; the introduction of piezoelectric technology can produce the separation of piezoelectric electron holes on the one hand, and the hydroxyl groups generated by the oxidation of piezoelectric electrons and holes can further mediate the activation of peracetic acid, and on the other hand, the ultrasonic cavitation bubble rupture can continuously stimulate the generation of dynamic defects on the CoOOH surface during the entire reaction process, increase the catalytic reaction active site activation oxidant, effectively solve the problem of the consumption of active sites on the catalyst surface during the catalytic process, and can achieve efficient and lasting pollutant removal. In addition, the introduction of piezoelectric technology also enhances the bactericidal and disinfecting ability of the system, effectively reduces the ecological risk of antibiotic pollution, and is more conducive to the practical application and promotion of advanced oxidation processes.

[0008] The technical solution of the present invention is as follows:

[0009] A method for treating antibiotic wastewater and eliminating biological toxicity by piezoelectric catalysis coupled with peracetic acid activation comprises the following steps:

[0010] CoOOH nanosheets are added to the wastewater to be treated, and then peracetic acid is added, and the wastewater is placed in a piezoelectric ultrasonic device for ultrasonic treatment under light-proof conditions. CoOOH produces dynamic oxygen vacancies under ultrasonic conditions, and the piezoelectric electrons generated by the excitation and the hydroxyls generated by the oxidation of holes directly activate the peracetic acid to achieve wastewater treatment.

[0011] Preferably according to the present invention, the wastewater to be treated is antibiotic wastewater.

[0012] Preferably according to the present invention, the antibiotic is a sulfonamide antibiotic.

[0013] Preferably according to the present invention, the sulfonamide antibiotic is sulfamethoxazole, sulfathiazole, sulfadiazine or sulfamethazine.

[0014] Preferably according to the present invention, the concentration of antibiotics in the antibiotic wastewater is 10-30 μmol / L, the solution pH is 5-11, and the temperature is 20°C.

[0015] Preferably according to the present invention, the dosage of CoOOH nanosheets in the wastewater to be treated is 0.05-0.2 g / L.

[0016] Preferably according to the present invention, the concentration of peracetic acid in the wastewater to be treated is 50-400 μmol / L.

[0017] Preferably according to the present invention, the ultrasonic power is 100-120W, the frequency is 30-50KHZ, and the entire reaction time is 15-45min.

[0018] According to the preferred embodiment of the present invention, the CoOOH nanosheets are prepared by the following method:

[0019] Add NaOH solution to Co 2+ The solution was stirred and mixed, then ultrasonically treated, and then NaClO solution was added and ultrasonically treated to obtain a dark brown sample, which was washed with water, centrifuged, and dried to obtain CoOOH.

[0020] According to the preferred embodiment of the present invention, the concentration of the NaOH solution is 0.5-2 mol / L; Co 2+ The solution is CoCl2 solution with a concentration of 8-12mmol / L, Co 2+ The volume ratio of solution to NaOH solution is 1:(2-6).

[0021] Preferably, according to the present invention, the ultrasonic treatment has an ultrasonic power of 100-120 W, a frequency of 30-50 KHZ, and an ultrasonic time of 1 min.

[0022] According to the preferred embodiment of the present invention, the concentration of the NaClO solution is 0.8-1 mol / L, and the NaClO solution and Co 2+ The solution volume ratio is 1:(15-25).

[0023] Preferably, according to the present invention, the ultrasonic treatment has an ultrasonic power of 100-120 W, a frequency of 30-50 KHZ, and an ultrasonic time of 10 min.

[0024] Preferably, according to the present invention, the washing is to wash the brown precipitate sample with deionized water, centrifuge and wash several times at 4000 rpm until the eluent is neutral, put it into a 60°C oven for drying for 12 hours, grind it into powder and pass it through a 100-mesh sieve.

[0025] The beneficial effects of the present invention are:

[0026] 1. The treatment method of the present invention is a novel advanced oxidation process, which uses CoOOH nanosheets as a catalyst and is assisted by piezoelectric technology to synergistically activate peracetic acid to treat antibiotic wastewater. The present invention introduces low-energy piezoelectric ultrasonic technology into the peracetic acid-based advanced oxidation process. On the one hand, CoOOH generates piezoelectric electrons under ultrasonic activation, which further promotes the activation of peracetic acid, and the piezoelectric electrons are captured by the peracetic acid. The recombination rate of piezoelectric electrons and holes is greatly reduced, thereby accelerating the removal of pollutants. On the other hand, the rupture of ultrasonic cavitation bubbles can promote the rapid generation of dynamic defects and active sites on the surface of CoOOH nanosheets, which solves the problem that the active sites of existing catalysts are difficult to regenerate and the recycling rate of catalysts is low, and can achieve efficient and lasting pollutant removal, thereby promoting the practical application of advanced oxidation processes.

[0027] 2. The active substances produced by the new advanced oxidation process developed by the present invention include RO·, 1 O2 and Co(IV)=O have strong ability to resist environmental background influences and show potential for treating actual wastewater; in addition, the process can also sterilize and eliminate resistance genes, thereby effectively treating antibiotic wastewater and reducing environmental risks.

[0028] 3. The synthesis method of the CoOOH nanosheets of the present invention is green, simple, high-yield, pollution-free, low-energy-consuming, and suitable for industrial production. The synthesized CoOOH can effectively activate peracetic acid to produce various active substances to degrade pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the XRD spectrum of the CoOOH nanosheets prepared in Example 1 of the present invention.

[0030] Figure 2 This is a TEM image of the CoOOH nanosheets prepared in Example 1 of the present invention.

[0031] Figure 3 This is the electron paramagnetic resonance (EPR) spectrum of the CoOOH nanosheets of Example 1 before and after ultrasonic treatment.

[0032] Figure 4 The figure is a comparison chart of the activation efficiency of peracetic acid in different systems of Example 1 of the present invention and Comparative Example 1.

[0033] Figure 5 This is a comparison chart of the performance of different systems in Example 1 of the present invention and Comparative Example 1 on the degradation of sulfathiazole.

[0034] Figure 6 The EPR spectra of different systems of Example 1 and Comparative Example 1 of the present invention are shown in FIG.

[0035] Figure 7 This is the instantaneous piezoelectric current spectrum of Example 1 of the present invention.

[0036] Figure 8 This is a recycling performance diagram of Example 1 of the present invention.

[0037] Fig. 9 This is Experimental Example 3: The effects of different coexisting anions on the degradation performance of sulfathiazole.

[0038] Fig.10 This is a comparison chart of the inactivation of resistant Escherichia coli in Experimental Example 4. DETAILED DESCRIPTION

[0039] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings, but is not limited thereto.

[0040] The raw materials used in the examples are all conventional commercially available products.

[0041] Embodiment 1,

[0042] Preparation of CoOOH nanosheets:

[0043] Take 25mL of 1mol / L NaOH solution and 10mmol / L Co 2+ 100 mL of the solution was mixed and stirred, and then placed in an ultrasonic instrument for ultrasonic treatment for 1 min, and then 0.9 mol / L NaClO solution was added and ultrasonic treatment was continued for 10 min. The obtained product was washed with water and centrifuged several times to obtain a dark brown solid material, which was placed in a 60°C oven for drying for 12 h, and then taken out and ground and sieved to obtain CoOOH nanosheet powder.

[0044] The XRD patterns of the synthesized CoOOH nanosheets are shown in Figure 1 shown.

[0045] TEM images of the synthesized CoOOH nanosheets are shown in Figure 2 As shown in Figure 2, the CoOOH catalyst exhibits a hexagonal sheet structure with a side length of about 50 nm.

[0046] The method for treating antibiotic wastewater based on CoOOH nanosheet piezoelectric catalysis coupled with peracetic acid activation is as follows:

[0047] At room temperature, 100 mL of a 20 μmol / L sulfathiazole simulated solution was added to a beaker, 10 mg of the CoOOH nanosheets prepared above and 200 μL of 0.1 mol / L peracetic acid were added, and the beaker was placed in an ultrasonic instrument with an ultrasonic power of 110 W and a frequency of 40 kHz for 30 min. During the reaction, 1 mL of the sample was taken out at regular intervals (0, 1, 2, 5, 10, 20, 30 min) and filtered through a 0.22 μm filter membrane. The sulfathiazole concentration was determined by high performance liquid chromatography to verify its degradation effect.

[0048] Experimental Example 1

[0049] The CoOOH nanosheet powder prepared in Example 1 was dispersed in 100 mL of water, and subjected to ultrasonic treatment for 30 min, dried, and then ground and sieved.

[0050] Electron paramagnetic resonance spectra of CoOOH nanosheets before and after ultrasonic treatment Figure 3 As shown. Figure 3 It can be seen that after the CoOOH nanosheets were treated with ultrasound, EPR captured more unpaired electron signals at g = 2.00, indicating that more oxygen vacancies were generated.

[0051] Comparative Example 1

[0052] The method for treating antibiotic wastewater based on CoOOH nanosheet piezoelectric catalysis coupled with peracetic acid activation as described in Example 1 is different in that:

[0053] The beaker was placed on a magnetic stirrer for stirring reaction at a speed of 750 rpm to replace the ultrasonic treatment. The remaining operations and amounts were exactly the same as those in Example 1.

[0054] Experimental Example 2

[0055] The treatment methods of Example 1 and Comparative Example 1, the activation efficiency of CoOOH / peracetic acid system under different effects of stirring and piezoelectric ultrasound on peracetic acid is compared. Figure 4 As shown. Figure 4 It can be seen that the introduction of piezoelectric ultrasonic technology greatly improved the activation efficiency of peracetic acid, indicating that piezoelectric technology has prompted the production of more active sites on the catalyst surface for activating peracetic acid.

[0056] Comparison of the performance of CoOOH / peracetic acid system in pollutant degradation under different conditions of stirring and piezoelectric ultrasound. Figure 5 As shown. Figure 5 It can be seen that the introduction of piezoelectric ultrasonic technology has greatly improved the system's performance in removing pollutants.

[0057] The EPR spectra of CoOOH / peracetic acid system under different stirring and piezoelectric ultrasound effects are shown in Figure 2. Figure 6 As shown. Figure 6 It can be seen that piezoelectric ultrasound causes more RO·, ·OH, 1 O2 and other active substances, thereby attacking sulfathiazole.

[0058] Example 1 Treatment Method The instantaneous piezoelectric current spectrum of the CoOOH / peracetic acid system is as follows Figure 7 As shown. Figure 7 It can be observed that during the on-off process of ultrasound, CoOOH undergoes regular electron-hole separation, further confirming that CoOOH has stable piezoelectric properties. In the presence of peracetic acid, the piezoelectric current generated increases by 3.5 times, indicating that peracetic acid can act as an electron acceptor of the material and reduce the recombination rate of electrons and holes.

[0059] Example 1 Treatment Method The experimental results of the cyclic degradation of pollutants by CoOOH / peracetic acid / piezoelectric system are as follows Figure 8 After eight cycles, the degradation efficiency of the system for pollutants can still reach 100%, showing extremely stable catalytic activity, indicating that the introduction of piezoelectric technology continuously promotes the generation of dynamic defects and maintains the catalytic activity of the system.

[0060] Experimental Example 3

[0061] The method for treating antibiotic wastewater based on CoOOH nanosheet piezoelectric catalysis coupled with peracetic acid activation as described in Example 1 is different in that:

[0062] Different types of common anions (Cl - , SO2 - , NO3 - ) to explore the application potential of this method in a real environment context.

[0063] Fig. 9 This is the comparison of the degradation performance of CoOOH / peracetic acid / piezoelectric system on sulfathiazole in the presence of different anions in Experimental Example 3. Fig. 9 It can be seen that the system can still efficiently remove pollutants in the presence of anions, showing excellent ability to resist environmental background.

[0064] Experimental Example 4

[0065] The concentration of resistant E. coli was 1×10 6 10 mg of CoOOH catalyst and 200 μL of 0.1 mol / L peracetic acid were added to the wastewater with CFU / mL, and ultrasonic treatment was performed for 30 min (CoOOH / PAA / US). Meanwhile, a control group without ultrasonic treatment (CoOOH / PAA) was used. During the reaction, 1 mL of sample was taken out at regular intervals (0, 1, 2, 5, 10, 20, 30 min). 200 μL of the sample was taken out and plated on a solid culture medium.

[0066] Fig.10 The figure shows the inactivation of resistant E. coli by CoOOH / peracetic acid / piezoelectric system and CoOOH / peracetic acid system. The inactivation efficiency of bacteria by CoOOH / peracetic acid piezoelectric system can reach 100% within 30 minutes, which is mainly due to the introduction of piezoelectric technology, which promotes the decomposition of peracetic acid to produce a large amount of RO· with bactericidal properties.

Claims

1. A method for treating antibiotic wastewater and eliminating biological toxicity by piezoelectric catalysis coupled with peracetic acid activation, comprising the following steps: CoOOH nanosheets are added to the wastewater to be treated, and then peracetic acid is added, and the wastewater is placed in a piezoelectric ultrasonic device for ultrasonic treatment under light-proof conditions. CoOOH produces dynamic oxygen vacancies under ultrasonic conditions, and the piezoelectric electrons generated by the excitation and the hydroxyls generated by the oxidation of holes directly activate the peracetic acid to achieve wastewater treatment.

2. The method according to claim 1, characterized in that The wastewater to be treated is antibiotic wastewater, the antibiotics are sulfonamide antibiotics, the sulfonamide antibiotics are sulfamethoxazole, sulfathiazole, sulfadiazine or sulfamethazine, the concentration of the antibiotics in the antibiotic wastewater is 10-30 μmol / L, the solution pH is 5-11, and the temperature is 20°C.

3. The method according to claim 1, characterized in that The dosage of CoOOH nanosheets in the wastewater to be treated is 0.05-0.2 g / L.

4. The method according to claim 1, characterized in that: The concentration of peracetic acid in the wastewater to be treated is 50-400 μmol / L.

5. The method according to claim 1, characterized in that: The ultrasonic power is 100-120W, the frequency is 30-50KHZ, and the entire reaction time is 15-45min.

6. The method according to claim 1, characterized in that CoOOH nanosheets were prepared as follows: Add NaOH solution to Co 2+ The solution was stirred and mixed, then ultrasonically treated, and then NaClO solution was added and ultrasonically treated to obtain a dark brown sample, which was washed with water, centrifuged, and dried to obtain CoOOH.

7. The method according to claim 6, characterized in that The concentration of the NaOH solution is 0.5-2 mol / L; Co 2+ The solution is CoCl2 solution with a concentration of 8-12mmol / L, Co 2+ The volume ratio of the solution to the NaOH solution is 1:(2-6), the ultrasonic treatment ultrasonic power is 100-120W, the frequency is 30-50KHZ, and the ultrasonic time is 1min.

8. The method according to claim 6, characterized in that The concentration of the NaClO solution is 0.8-1 mol / L. 2+ The solution volume ratio is 1:(15-25).

9. The method according to claim 1, characterized in that: The ultrasonic treatment has an ultrasonic power of 100-120W, a frequency of 30-50KHZ, and an ultrasonic time of 10min.

10. The method according to claim 1, characterized in that The washing comprises washing the brown precipitate sample with deionized water, centrifuging and washing for several times at 4000 rpm until the eluent is neutral, drying in an oven at 60° C. for 12 hours, grinding into powder and passing through a 100-mesh sieve.

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