Method for the preparation of ceramic microbial particle electrodes for three-dimensional electrocatalysis

Abstract

The application discloses a preparation method of a ceramic microbial particle electrode for three-dimensional electrocatalysis, and aims to solve the problem that nitrogen, phosphorus and macromolecular organic pollutants in wastewater are difficult to remove.The preparation method comprises the following steps: firstly, mixing clay and water glass, adding zinc oxide powder and Fe3O4 powder, stirring to obtain granular clay; secondly, aging the granular clay at 24-30 DEG C; thirdly, placing the aged granular clay into a muffle furnace for heat treatment at 1000-1200 DEG C to obtain ceramic particles with pores; and fourthly, adding the ceramic particles with pores into domesticated sludge for microbial loading, and obtaining the ceramic microbial particle electrode for three-dimensional electrocatalysis after the biological membrane covers the ceramic particles.The ceramic microbial particle electrode has a porous surface form, has a good adsorption effect on pollutants, and can realize the synchronous removal of difficult-to-degrade pollutants and denitrification and dephosphorization through electrocatalysis and microbial action.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of environmental protection and water treatment, and particularly relates to a preparation method of a ceramic microbial particle electrode applied to three-dimensional electro-catalytic treatment of refractory pollutants in wastewater and capable of simultaneous nitrogen and phosphorus removal. BACKGROUND

[0002] Water eutrophication is one of the environmental problems to be solved, and the excessive nitrogen and phosphorus in water bodies has caused great trouble to water health. At present, the biological method most widely applied to nitrogen and phosphorus removal has a long operation cycle, is difficult to start, and has a high time cost. The physical method has problems such as desorption, and it is difficult to completely remove pollutants. The ordinary chemical method is easy to cause secondary pollution, and has a large energy cost, so it is not suitable for long-term treatment of large polluted water bodies.

[0003] Nowadays, various industries are developed in the world, and the water pollution caused by them is more complex. Many water bodies often have multiple problems, especially various refractory pollutants widely exist in a large amount of water bodies, forming the situation of "one water body and multiple pollutants", so it is particularly important to design a technology suitable for treating refractory pollutants and capable of fully utilizing energy while removing nitrogen and phosphorus. SUMMARY

[0004] The purpose of the application is to solve the problem that nitrogen, phosphorus and macromolecular organic pollutants in wastewater are difficult to remove, and provide a preparation method of a three-dimensional electro-catalytic particle electrode capable of efficiently removing refractory pollutants and simultaneously removing nitrogen and phosphorus.

[0005] The preparation method of the ceramic microbial particle electrode for three-dimensional electro-catalysis is realized according to the following steps:

[0006] I. Mix the pottery clay and water glass, then add zinc oxide powder and Fe3O4 powder, stir uniformly to form granules, and obtain pottery clay granules;

[0007] II. Age the pottery clay granules at 24-30 DEG C for 12-18 hours, and dry to obtain aged pottery clay granules;

[0008] III. Put the aged pottery clay granules into a muffle furnace and heat treat at 1000-1200 DEG C to obtain ceramic particles with pores;

[0009] IV. Acclimate the return sludge of the secondary sedimentation tank of a sewage treatment plant, after the acclimation is completed, load the ceramic particles with pores into the acclimated sludge to load microorganisms, and after the biological membrane covers the ceramic particles, obtain the ceramic microbial particle electrode for three-dimensional electro-catalysis;

[0010] In step I, 0.1-0.3 mol of zinc oxide powder is added per kilogram of pottery clay, and 0.3-0.5 mol of Fe3O4 powder is added per kilogram of pottery clay.

[0011] The three-dimensional electrocatalytic ceramic microbial particle electrode can carry out electrolysis and denitrification processes, and the hydrogen generated by electrolysis can be used as an electron donor to realize autotrophic denitrification and provide the required energy for the bacteria. - -N is reduced to NO2 - -N, and further reduced to N2. The micro-electric stimulation can make the microorganisms more active, the magnetic field generated by Fe3O4 can stimulate the growth of the organisms, increase the biomass of the system, and increase the enzyme activity of the microorganisms, and the biological denitrification and phosphorus removal are facilitated. The physical, chemical and biological actions occur simultaneously in the system, and the main electrode and the particle electrode can degrade the refractory pollutants through electrocatalysis. Through the synergistic effect of biology, electrochemistry and micro-magnetic field, the pollutants are efficiently removed, and the denitrification and phosphorus removal effects are achieved.

[0012] The three-dimensional electrocatalytic ceramic microbial particle electrode has a porous surface form, has a good adsorption effect on pollutants, and realizes the simultaneous removal of refractory pollutants and denitrification and phosphorus removal through electrocatalysis and microbial action. Fe3O4 is doped to form a micro-magnetic field in the system, stimulate the activity of microorganisms and enzymes, and improve the stability of the electrocatalytic system. After the removal of sulfamethoxazole, the removal rate can reach more than 90%, the average removal rates of TN and TP can reach more than 80% and 70% respectively. The whole electrocatalytic system has a good effect on removing pollutants and is more widely applicable. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The figure is a total nitrogen concentration change curve of wastewater treated by the ceramic microbial particle electrode in the example for 16h, wherein 1 represents no particle electrode, 2 represents no zinc oxide particle electrode, 3 represents no Fe3O4 particle electrode, and 4 represents the ceramic microbial particle electrode in the example;

[0014] Figure 2 The figure is a total phosphorus concentration change curve of wastewater treated by the ceramic microbial particle electrode in the example for 16h;

[0015] Figure 3 The figure is a degradation curve of sulfamethoxazole in wastewater treated by the ceramic microbial particle electrode in the example for 16h;

[0016] Figure 4 The figure is a mechanism diagram of wastewater treated by the ceramic microbial particle electrode in the example;

[0017] Figure 5 The figure is a scanning electron microscope image of the microorganisms on the ceramic microbial particle electrode prepared in the example. DETAILED DESCRIPTION

[0018] Embodiment 1: The preparation method of the three-dimensional electrocatalytic ceramic microbial particle electrode is implemented according to the following steps:

[0019] I. Mix the clay and water glass, then add zinc oxide powder and Fe3O4 powder, stir uniformly to form granules, and obtain clay granules;

[0020] II. Age the clay granules at 24-30℃ for 12-18h, and dry to obtain aged clay granules;

[0021] III. Put the aged clay granules into a muffle furnace and heat treat at 1000-1200℃ to obtain ceramic particles with pores;

[0022] IV. Acclimate the return sludge of the secondary sedimentation tank of a sewage treatment plant, and after acclimation, add the ceramic particles with pores to the acclimated sludge to load microorganisms, and when the biofilm covers the ceramic particles, obtain the three-dimensional electrocatalytic ceramic microbial particle electrode;

[0023] In step I, 0.1-0.3 mol of zinc oxide powder is added per kilogram of clay, and 0.3-0.5 mol of Fe3O4 powder is added per kilogram of clay.

[0024] In this embodiment, both ZnO and Fe3O4 powder are biocompatible materials, ZnO enhances water adsorption, causing water to accumulate on the surface of the particle electrode, and ZnO and Fe3O4 work together to accelerate the attachment and growth of the biofilm. At the same time, under the action of electrocatalysis, ZnO and Fe3O4 generate more ·OH, which oxidizes and decomposes pollutants in water.

[0025] The ZnO / Fe3O4 / ceramic / microbial particle prepared in this embodiment serves as a particle electrode, so that the system integrates physical, chemical and biological effects, making it possible to degrade and remove refractory pollutants, nitrogen and phosphorus through multiple pathways.

[0026] Embodiment 2: The difference between this embodiment and embodiment 1 is that the mass ratio of clay to water glass in step I is (300-400):(24-45).

[0027] Embodiment 3: The difference between this embodiment and embodiment 2 is that the mass ratio of clay to water glass in step I is (380-400):(35-45).

[0028] Embodiment 4: The difference between this embodiment and embodiment 1 or 2 is that the diameter of the clay granules in step I is 5-20mm.

[0029] Embodiment five: The difference between this embodiment and one of the embodiments one to four is that the diameter of the clay particles is 10-15 mm.

[0030] Embodiment six: The difference between this embodiment and one of the embodiments one to five is that in step one, 0.15 mol of zinc oxide powder is added per kilogram of clay, and 0.4 mol of Fe3O4 powder is added per kilogram of clay.

[0031] Embodiment seven: The difference between this embodiment and one of the embodiments one to six is that in step two, the aging treatment is carried out at 25°C for 15 h.

[0032] Embodiment eight: The difference between this embodiment and one of the embodiments one to seven is that in step two, the drying is carried out in a forced air drying oven at a temperature of 60-80°C.

[0033] Embodiment nine: The difference between this embodiment and one of the embodiments one to eight is that in step three, the heat treatment time is 2-4 h.

[0034] Embodiment ten: The difference between this embodiment and one of the embodiments one to nine is that in step three, the heat treatment is carried out at 1000°C for 2 h.

[0035] Example: This example is for the preparation method of a three-dimensional electrocatalytic ceramic microbial particle electrode, which is carried out according to the following steps:

[0036] I. 400 g of clay and 40 g of water glass (adhesive) are mixed, then zinc oxide powder and Fe3O4 powder are added, stirred uniformly to form granules, and clay particles (diameter 10 mm) are obtained;

[0037] II. The clay particles are aged at 25°C for 15 h, dried in a forced air drying oven for 6 h, and aged clay particles are obtained;

[0038] III. The aged clay particles are placed in a muffle furnace and heat treated at 1000°C for 2 h to obtain ceramic particles with pores;

[0039] IV. The return sludge in the secondary sedimentation tank of a sewage treatment plant is acclimated, and after acclimation is complete, the ceramic particles with pores are added to the acclimated sludge to load microorganisms. When the biofilm covers the ceramic particles, a three-dimensional electrocatalytic ceramic microbial particle electrode (ZnO / Fe3O4 / ceramic / microbial particle electrode) is obtained.

[0040] In step one, 0.15 mol of zinc oxide powder is added per kilogram of clay, and 0.4 mol of Fe3O4 powder is added per kilogram of clay.

[0041] The ZnO / Fe3O4 / ceramic / microorganism particle electrode obtained in the embodiment is used to electrocatalytically degrade pollutants. The concentrations of various pollutants in the wastewater simulate the effluent from the secondary sedimentation tank of a sewage treatment plant, wherein the concentration of NaNO3 is 0.18 g / L, the concentration of KH2PO4 is 0.015 g / L, the concentration of MgCl2·6H2O is 0.014 g / L, the concentration of CaCl2·2H2O is 0.005 g / L, the concentration of NaHCO3 is 0.5 g / L, and the concentration of FeCl3·6H2O is 1.5 g / L. Sulfamethoxazole is further added to the wastewater as a refractory pollutant. The influent of the simulated wastewater has the following water quality: COD: 55-60 mg / L, NO3 - N: 35 mg / L, TP: 3 mg / L, pH: 7-8, and sulfamethoxazole: 50 mg / L.

[0042] A graphite rod is used as a main electrode, the volume of the reactor is 500 mL, the ZnO / Fe3O4 / ceramic / microorganism particle electrode is filled in the reactor to 1 / 3 of the volume of the reactor, a direct current power supply is used to gradually increase the current intensity from 0 mA to 60 mA, the microorganisms on the particle electrode are gradually adapted to the current, and when the effluent water quality tends to be stable, it is indicated that the system is successfully started. Sulfamethoxazole is further added, so that the concentration of sulfamethoxazole is 50 mg / L. According to the results shown in Table 1, after the addition of sulfamethoxazole, it is found that the average removal rate of sulfamethoxazole can reach more than 93% after 16 h of treatment, the average removal rate of TN can reach more than 87%, and the average removal rate of TP can reach more than 71%. Figures 1-3 After the system is operated for 60 days, the average removal rates of sulfamethoxazole and TN are stable, and the average removal rate of TP slightly decreases, but can still reach more than 67%. Therefore, the system can realize the simultaneous removal of refractory pollutants such as sulfamethoxazole and nitrogen and phosphorus, and has good stability.

Claims

1. A method for the preparation of ceramic microbial particle electrodes for three- dimensional electrocatalysis, characterized by The preparation method is realized according to the following steps: I. The pottery clay and water glass are mixed, then the zinc oxide powder and Fe3O4 powder are added, and the mixture is stirred uniformly to form granular particles, thereby obtaining pottery clay particles; II. The pottery clay particles are aged at 24-30 DEG C for 12-18 h, and then dried to obtain aged pottery clay particles; III. The aged pottery clay particles are placed in a muffle furnace and heat-treated at 1000-1200 DEG C, thereby obtaining ceramic particles with pores; IV. The sludge in the secondary sedimentation tank of a sewage treatment plant is domesticated, and after the domestication is completed, the ceramic particles with pores are added to the domesticated sludge to load microorganisms, and when the biofilm covers the ceramic particles, the ceramic microorganism particle electrode for three-dimensional electro-catalysis is obtained. In step I, 0.15 mol of zinc oxide powder is added per kg of pottery clay, and 0.4 mol of Fe3O4 powder is added per kg of pottery clay.

2. The method for preparing a three-dimensional electrocatalytic ceramic microbial particle electrode according to claim 1, characterized by In step I, the mass ratio of pottery clay to water glass is (300-400):(24-45).

3. The method for preparing a three-dimensional electrocatalytic ceramic microbial particle electrode according to claim 2, characterized by In step I, the mass ratio of pottery clay to water glass is (380-400):(35-45).

4. The method for preparing a three-dimensional electrocatalytic ceramic microbial particle electrode according to claim 1, characterized by In step I, the diameter of the pottery clay particles is 5-20 mm.

5. The method for the preparation of a three-dimensional electrocatalytic ceramic microbial particle electrode according to claim 4, characterized by In step I, the diameter of the pottery clay particles is 10-15 mm.

6. The method for preparing a three-dimensional electrocatalytic ceramic microbial particle electrode according to claim 1, characterized by In step II, the aging treatment is performed at 25 DEG C for 15 h.

7. The method for preparing a three-dimensional electrocatalytic ceramic microbial particle electrode according to claim 1, characterized by In step II, the drying is performed at a temperature of 60-80 DEG C in a blast drying oven.

8. The method for preparing a three-dimensional electrocatalytic ceramic microbial particle electrode according to claim 1, characterized by In step III, the heat treatment time is 2-4 h.

9. The method for preparing a three-dimensional electro-catalytic ceramic microbial particle electrode according to claim 1, characterized in that In step III, the heat treatment is performed at 1000 DEG C for 2 h.

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