Water pollutant degradation device and method based on enzyme immobilized magnetic carrier

Abstract

The invention discloses a water pollutant degradation device and method based on an enzyme immobilized magnetic carrier, which organically combines the high efficiency of biological enzyme catalysis and the convenience of magnetic separation, and provides an innovative solution for water pollution treatment. The core of the device is a magnetic enzyme carrier, Fe3O4 nanoparticles are used as a magnetic response core, a degrading enzyme is covalently immobilized after surface functionalization of a silane coupling agent, a reaction system adopts an ultrasonic enhancement technology, and the mass transfer efficiency and the reaction rate are remarkably improved through a cavitation effect. The magnetic separation system utilizes a 0.1-0.3 T adjustable magnetic field to realize efficient separation and recovery of the carrier. The whole treatment process is simple and convenient to operate, mild in condition and free of secondary pollution, is suitable for treating industrial wastewater containing organic pollutants, and has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of water pollution control, and in particular to a water pollutant degradation device combining bio-enzyme technology with magnetic separation technology and an application method thereof. Background Art

[0002] Industrial wastewater containing difficult-to-degrade organic pollutants such as phenols, anilines, and dyes poses a serious threat to the ecological environment and human health. While traditional physical and chemical treatment methods such as coagulation and sedimentation, activated carbon adsorption, and membrane separation can remove some pollutants, they suffer from high energy consumption, high operating costs, susceptibility to secondary pollution, and limited effectiveness in treating complex organic matter. Biological treatment technology has attracted widespread attention due to its environmental friendliness and strong selectivity. Enzyme catalysis has become a research hotspot due to its high efficiency, specificity, and mild reaction conditions. Oxidase enzymes such as laccase and peroxidase can effectively degrade a variety of organic pollutants, converting them into low-toxic or non-toxic products.

[0003] However, existing enzyme treatment technologies face many challenges in practical applications. First, free enzymes are difficult to recover during the treatment process, resulting in high operating costs and limiting their industrial application; second, enzymes have poor stability in complex wastewater environments and are easily inactivated, affecting the sustainability of the treatment effect; third, although traditional enzyme immobilization technologies such as embedding and adsorption methods have solved the problem of enzyme recovery to a certain extent, they have defects such as difficulty in carrier separation, low immobilization efficiency, and poor mechanical strength. Magnetic separation technology has been introduced into the field of biotreatment due to its advantages such as simple operation, high separation efficiency, and no need for additional separation equipment. However, the existing magnetic enzyme carrier preparation process is complex, the enzyme activity on the carrier surface is severely lost, and the magnetic responsiveness is insufficient. These problems still need to be solved. Therefore, the development of a water pollution control technology that integrates efficient enzyme catalysis, convenient magnetic separation, and carrier recycling has important theoretical significance and practical value. Summary of the Invention

[0004] The present invention provides a water pollutant degradation device based on enzyme-immobilized magnetic carriers, which cleverly combines bio-enzyme catalysis technology with magnetic separation technology to achieve efficient degradation of organic pollutants in water and convenient recovery of enzyme carriers.

[0005] The core component of the device is a magnetic enzyme carrier, which uses Fe3O4 magnetic nanoparticles as the magnetic responsive core. The outer layer is surface-functionalized with a silane coupling agent, and then the degradation enzyme molecules are covalently bonded to the carrier surface to form a composite material with high magnetic responsiveness and excellent enzyme activity.

[0006] The particle size of the carrier is controlled in the range of 50-200 nm, which not only ensures good dispersibility and reactivity, but also has sufficient magnetization intensity (≥40 emu / g) to achieve efficient magnetic separation. The enzyme immobilization density is maintained at 5-15 mg / g carrier, ensuring sufficient catalytic active sites.

[0007] The device's reaction system consists of a cylindrical reactor designed with a water inlet and outlet to ensure continuous or intermittent treatment. A bottom-mounted ultrasonic generator generates ultrasonic waves with a frequency of 20-40 kHz and a power density controlled at 0.1-0.5 W / cm³. This enhances the mass transfer process through the ultrasonic cavitation effect, improving the contact efficiency between the enzyme and the pollutant, thereby significantly accelerating the reaction rate.

[0008] The magnetic separation system utilizes an external permanent magnet design with adjustable magnetic field strength between 0.1 and 0.3 T. This precisely controlled magnetic field distribution enables efficient carrier separation and collection. A recirculation system, including a circulation pump and flow control valve, ensures thorough mixing of materials during the reaction and provides a convenient flow path for carrier recycling.

[0009] The working process of the entire device is as follows: the sewage to be treated is first injected into the reactor, and then the magnetic enzyme carrier is added at a ratio of 1:1000-5000 of the carrier to the sewage mass. The ultrasonic system is started to assist the reaction for 30-120 minutes. After the reaction is completed, an external magnetic field is applied to separate the carrier from the treated liquid. Finally, the purified water is collected and the carrier is recovered for the next round of treatment cycle.

[0010] Beneficial effects of the present invention: Ultrasonic-assisted technology significantly enhances the contact efficiency between enzymes and pollutants, increases the reaction rate, and greatly shortens the processing time. The synergistic catalytic effect of the composite enzyme system further broadens the scope of pollutant treatment and realizes efficient purification of complex industrial wastewater. The magnetic separation system can achieve efficient recovery of the carrier, avoiding the problem of serious enzyme loss in traditional biological treatment. The magnetic enzyme carrier has excellent reusability, and the entire treatment process is easy to operate. Magnetic separation does not require complex solid-liquid separation equipment and has a high degree of automation, reducing manual operation and equipment investment. The reaction conditions are mild and can be carried out at room temperature and pressure. The energy consumption is low and no chemical reagents need to be added, which avoids the generation of secondary pollution and has good environmental compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of the water pollutant degradation device based on enzyme-immobilized magnetic carrier DETAILED DESCRIPTION

[0012] Example 1: Preparation of magnetic enzyme carrier.

[0013] The preparation process of magnetic enzyme carriers is divided into three consecutive steps.

[0014] The first step is to prepare Fe3O4 magnetic nanoparticles as the carrier core. 5.4g of FeCl3·6H2O and 2.0g of FeC2·4H2O are completely dissolved in 200mL of deionized water. Ammonia is slowly added dropwise under nitrogen to adjust the pH to 10-11. The reaction system is stirred at 80°C for 2 hours, during which the solution gradually turns black. After the reaction is complete, the black Fe3O4 magnetic nanoparticles are separated using an external magnet and washed several times with deionized water and ethanol alternately until neutral.

[0015] The second step is to functionalize the carrier surface. The prepared magnetic particles are redispersed in 200 mL of anhydrous ethanol and 5 mL of 3-aminopropyltriethoxysilane is added. The entire reaction system is refluxed and stirred at 60°C for 12 hours to allow the silane coupling agent to form a stable coating layer on the particle surface and introduce active amino groups. After the reaction, magnetic separation is performed and the unreacted silane compound is removed by washing with ethanol.

[0016] The third step is enzyme immobilization, using glutaraldehyde as a crosslinker to covalently bind the enzyme to the carrier. The surface-modified magnetic carrier is dispersed in phosphate buffer (pH 7.0). An appropriate amount of glutaraldehyde solution is added to activate the amino groups on the carrier surface. Laccase solution (enzyme activity of 200 U / mL) is then added. The immobilization reaction is carried out at 4°C for 24 hours to maintain enzyme activity. During the reaction, one end of the glutaraldehyde molecule binds to the amino groups on the carrier surface, while the other end forms a covalent bond with the amino residue of the enzyme molecule, firmly anchoring the enzyme to the carrier surface. After immobilization, the free enzyme and excess crosslinker are removed by washing with phosphate buffer, resulting in a magnetic enzyme carrier with an enzyme activity of 150-200 U / g. The carrier is brown-black in color and can rapidly aggregate and separate under the influence of an external magnetic field.

[0017] Example 2: Phenol wastewater treatment

[0018] In order to verify the treatment effect of the device, a treatment experiment was carried out using simulated phenol wastewater with a concentration of 100 mg / L.

[0019] First, the pH of the simulated wastewater was adjusted to 6.0, the optimal pH range for laccase activity. The wastewater was then injected into the reactor. The prepared magnetic enzyme carrier was added at a mass ratio of 1:500 (2 g / L). The ultrasonic system was activated, with an ultrasonic power density of 0.3 W / cm³ and a reaction temperature of 25°C.

[0020] With the assistance of ultrasound, mass transfer in the reaction system was significantly enhanced, the carrier dispersion became more even, and the contact probability between the enzyme and phenol molecules was greatly increased. After 60 minutes of reaction, the phenol concentration dropped to 3.5 mg / L, with a removal efficiency of 96.5%. At the same time, the COD dropped from an initial 230 mg / L to 18 mg / L, with a removal efficiency of 92.3%.

[0021] Immediately after the reaction, the magnetic separation system was activated, applying a 0.2 T magnetic field. Under the influence of the field, the magnetic enzyme carriers rapidly migrated toward the magnetic poles and aggregated into clusters. The carriers were then collected and recovered by the carrier separation device, achieving a carrier recovery rate of 98.2%. The recovered carriers were washed with a simple buffer solution and could be directly used in the next round of treatment. After 20 consecutive uses, the carriers retained over 85% of their initial enzyme activity, demonstrating the reusability and cost-effectiveness of this technology. The treated water samples were clear and transparent, and all water quality indicators met discharge standards.

[0022] Example 3: Treatment of printing and dyeing wastewater.

[0023] The treatment target was actual printing and dyeing wastewater from a textile mill. This wastewater, characterized by a COD of 450 mg / L, a chromaticity of 800 times, and a pH of 8.5, contained various azo dyes and auxiliaries, making it a typical refractory industrial wastewater. Due to the complexity of this wastewater, a composite enzyme system was employed, immobilizing a laccase and peroxidase mixture in a 3:1 ratio on a magnetic carrier to enhance degradation of various pollutants. Prior to treatment, the wastewater pH was adjusted to 7.0, and then treatment was performed at a carrier dosage of 3 g / L. Due to the high concentration of pollutants in the wastewater, the reaction time was extended to 90 minutes, and the ultrasonic power was appropriately increased to 0.4 W / cm³.

[0024] Under the synergistic effect of the complex enzyme system, the organic dye molecules in the wastewater are gradually decomposed, the macromolecular compounds are broken into small molecular fragments, and finally mineralized into harmless small molecule products. After 90 minutes of treatment, the COD of the wastewater dropped to 46 mg / L, the removal rate reached 89.7%, the chroma dropped to 48 times, the decolorization rate was 94.2%, and the wastewater changed from its original deep red to almost colorless and transparent. More importantly, the carrier showed excellent stability in such a complex wastewater environment and could still maintain more than 85% of the enzyme activity after 25 repeated uses, indicating that the preparation process and immobilization method of the carrier can effectively protect the enzyme molecules from the influence of complex environments. This example fully demonstrates the treatment effect and practical value of the technology of the present invention on actual industrial wastewater.

Claims

1. A water pollutant degradation device based on enzyme-immobilized magnetic carrier, characterized in that include: (1) Magnetic enzyme carrier, consisting of Fe3O4 magnetic nanoparticles, a silane coupling agent coating layer, and a covalently bound degrading enzyme; (2) a reactor having a water inlet, a water outlet and an ultrasonic generator; (3) Magnetic separation system, including external permanent magnets and magnetic field adjustment device; (4) Circulation reflux system.

2. The device according to claim 1, characterized in that: The particle size of the magnetic carrier is 50-200 nm, the saturation magnetization intensity is ≥40 emu / g, and the enzyme immobilization density is 5-15 mg / g.

3. The device according to claim 1, characterized in that: The frequency of the ultrasonic generator is 20-40 kHz, and the power density is 0.1-0.5 W / cm3.

4. The device according to claim 1, characterized in that: The silane coupling agent coating layer is selected from one or more of 3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and the coating layer has a thickness of 2-10 nm.

5. The device according to claim 1, characterized in that: The permanent magnet in the magnetic separation system is made of neodymium iron boron material, the magnetic field strength can be adjusted within the range of 0.05-0.5T, and the magnetic field distribution uniformity is ≥90%.

6. The device according to claim 1, characterized in that: The reactor is a cylindrical structure with a length-to-diameter ratio of 2:1-5:

1. The inner wall is made of corrosion-resistant material and an ultrasonic transducer array is provided at the bottom.

7. A method for degrading water pollutants using the device according to claim 1, comprising the following steps: (1) Injecting the wastewater to be treated into the reactor; (2) Adding magnetic enzyme carrier at a carrier:wastewater mass ratio of 1:1000-5000; (3) Start the ultrasound-assisted reaction for 30-120 minutes; (4) applying a 0.1-0.3T magnetic field to separate and recover the carrier; (5) Collect purified water.

8. The method according to claim 7, wherein: The degradation enzyme is selected from one or more combinations of laccase, peroxidase, tyrosinase and cellulase, and the enzyme activity retention rate is ≥85% during the treatment process.

9. The method according to claim 7, wherein: The method further comprises a carrier regeneration step: washing the recovered magnetic enzyme carrier with a buffer solution to remove adsorbed pollutants and metabolites, and recycling the recovered magnetic enzyme carrier after activation treatment.

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