NL2030939A

NL2030939A - Nickel-iron bimetallic three-dimensional electrode particle filler and preparation method and application thereof

Info

Publication number: NL2030939A
Application number: NL2030939A
Authority: NL
Inventors: Zhu Suiyi; Lin Yingzi; Li Siwen; Liu Gen
Original assignee: Univ Jilin Jianzhu
Priority date: 2021-09-10
Filing date: 2022-02-15
Publication date: 2022-05-24
Also published as: NL2030939B1; CN113716655A; CN113716655B

Abstract

The present disclosure relates to the technical ﬁeld of slightly-polluted wastewater treatment, and provides a nickel-iron bimetallic three-dimensional electrode particle filler and a preparation method and application thereof. The present disclosure employs the liquid phase reduction method to load the nickel-iron bimetal on the granular activated carbon to form a bimetal particle electrode. The bimetal has a synergistic catalytic function, can promote the generation of hydroxyl radicals, increase the reaction rate, and strengthen the overall performance of the particle filler, and the ﬁnally obtained particle filler has good stability and high reproducibility, applying the particle filler of the present disclosure to a three-dimensional electrode reactor can significantly improve the degradation efﬁciency of organic pollutants, so that the three-dimensional electrode reactor has broader application prospects.

Description

NICKEL-IRON BIMETALLIC THREE-DIMENSIONAL ELECTRODE PARTICLE FILLER AND PREPARATION METHOD AND APPLICATION THEREOF TECHNICAL FIELD

[01] The present disclosure relates to the technical field of micro-polluted wastewater treatment, in particular to nickel-iron bimetallic three-dimensional electrode particle filler and a preparation method and application thereof.

BACKGROUND ART

[02] As a new advanced oxidation technology, electrochemical method has the advantages of low operating cost, high efficiency, and environmental friendliness. It has attracted the attention of many scientific researchers domestic and abroad.

[03] The three-dimensional electrode is a kind of electrochemical catalytic oxidation technology, which produces strong oxidant hydroxyl radicals during the reaction, thereby catalyzing the degradation of organic matter. It is an effective method for treating slightly-polluted wastewater. The particle filler in the three-dimensional electrode is the key part of the technology, and its performance directly affects the treatment effect of pollutants. The filler particles are polarized under the action of an electric field to form bipolar particles. The bipolar particles form a micro electrolytic cell, and generate hydroxyl radicals on the surface of the particle electrode to undergo oxidation-reduction reactions with organic substances, which greatly reduce the migration distance of organic substances and improves mass transfer effect of substances, and improve the space utilization rate of the reactor.

[04] At present, the commonly used particle electrodes are granular or detrital fillers such as granular activated carbon, activated alumina, ceramic particles, etc. However, these particle electrodes have the problems of long reaction time and low processing efficiency.

SUMMARY

[05] In view of this, the present disclosure provides a nickel-iron bimetallic three-dimensional electrode particle filler and a preparation method and application thereof.

The nickel-iron bimetallic three-dimensional electrode particle filler provided by the present disclosure has rapid reaction, good effect of degrading organic matter, high processing efficiency, good stability and high repetitive utilization rate.

[06] In order to achieve the above-mentioned purpose of the present disclosure, the present disclosure provides the following technical solutions:

[07] A preparation method of nickel-iron bimetallic three-dimensional electrode particle filler, wherein it comprises the following steps:

[08] Soak the granular activated carbon in sulfuric acid solution and to modify, wash and dry in sequence to obtain pretreated activated carbon;

[09] Mix the pretreated activated carbon, the iron salt-nickel salt mixed solution and the reducing agent to perform a reduction reaction to obtain a nickel-iron bimetallic three-dimensional electrode particle filler.

[10] Preferably, a concentration of the sulfuric acid solution is 0.05-0.5 mol/L, and a time of the soaking modification is 15-30 min.

[11] Preferably, the iron salt in the iron salt-nickel salt mixed solution is selected from a group consisting of ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, ferric nitrate, nitric acid and a mixture thereof, the nickel salt in the iron salt-nickel salt mixed solution is selected from a group consisting of nickel chloride, nickel sulfate, nickel nitrate and a mixture thereof.

[12] Preferably, a mass ratio of the iron element and the nickel element in the iron salt-nickel salt mixed solution is 1:2 to 2:1; the total mass of iron salt and nickel salt in the iron salt -nickel salt mixed solution is 1% to 5% of the mass of the pretreated activated carbon.

[13] Preferably, the reducing agent comprises NaBH, and/or KBHy; a molar ratio of total molar amount of iron and nickel in the iron salt-nickel salt mixed solution and the molar amount of the reducing agent is 1:1-2.

[14] Preferably, the process of mixing the pretreated activated carbon, the iron salt-nickel salt mixed solution and the reducing agent comprises: mixing the pretreated activated carbon, the iron salt-nickel salt mixed solution, and then under the protective atmosphere and stirring conditions, add the reducing agent solution dropwise to the obtained mixture liquid.

[15] Preferably, a temperature of the reduction reaction is room temperature and a time is 15-30 min.

[16] The present disclosure also provides the nickel-iron bimetallic three-dimensional electrode particle filler prepared by the preparation method described in the above solution, which comprises a granular activated carbon carrier and nickel nanoparticles and iron nanoparticles loaded on the granular activated carbon carrier.

[17] Preferably, the mass fraction of nickel nanoparticles in the nickel-iron bimetallic three-dimensional electrode particle filler 1s 1% to 5%, and the mass fraction of iron nanoparticles is 1% to 5%.

[18] The present disclosure also provides a use of the nickel-iron bimetallic three-dimensional electrode particle filler in the electrocatalytic degradation of organic pollutants.

[19] The present disclosure provides a method for preparing a nickel-iron bimetallic three-dimensional electrode particle filler, which comprises the following steps: soaking granular activated carbon with a sulfuric acid solution to modify and then sequentially washing and drying to obtain pretreated activated carbon; The iron salt-nickel salt mixed solution and the reducing agent are mixed to perform a reduction reaction to obtain a nickel-iron bimetallic three-dimensional electrode particle filler. The present disclosure uses a liquid phase reduction method to load a nickel-iron bimetal on a granular activated carbon carrier to form a bimetallic particle electrode. The bimetal has a synergistic catalytic function, can promote the generation of hydroxyl radicals, increase the reaction rate, and strengthen the overall performance of the particle filler. Applying it to a three-dimensional electrode reactor can improve the treatment efficiency of organic pollutants. In addition, the nickel-iron bimetallic three-dimensional electrode particle filler provided by the present disclosure has stable performance, long use time, and high repetitive utilization. The results of the examples show that the particle filler prepared by the present disclosure does not need to be replaced after 50 times of repeated use, and the degradation efficiency can still reach more than 85% after 50 times of use.

[20] The present disclosure also provides the nickel-iron bimetallic three-dimensional electrode particle filler prepared by the preparation method described in the above scheme and its application in electrocatalytic degradation of organic pollutants. The filler provided by the present disclosure reacts quickly, has a good effect of degrading organic matter, and has a high repetitive utilization rate. It can significantly improve the treatment efficiency of organic pollutants by electrocatalytic degradation, so that the three-dimensional electrode reactor has broader application prospects, especially has broad application prospects in the treatment of micro-polluted organic wastewater containing medicines and personal care products.

BRIEF DESCRIPTION OF THE DRAWINGS

[21] Figure 1 is an electron micrograph of the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1;

[22] Figure 2 is the IR spectrum of the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1;

[23] Figure 3 shows the effect of different cell voltages on the degradation of sulfamethizole;

[24] Figure 4 shows the effect of different particle filler dosages on the degradation effect of sulfamethizole;

[25] Figure 5 shows the effect of different electrode plate spacing on the degradation of sulfamethizole;

[26] Figure 6 shows the effect of the initial concentration of sulfamethizole on the degradation effect.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[27] The present disclosure provides a method for preparing a nickel-iron bimetallic three-dimensional electrode particle filler, which comprises the following steps:

[28] Soak the granular activated carbon in sulfuric acid solution and to modify, wash and dry in sequence to obtain pretreated activated carbon; 5 [29] Mix the pretreated activated carbon, the iron salt-nickel salt mixed solution and the reducing agent to perform a reduction reaction to obtain a nickel-iron bimetallic three-dimensional electrode particle filler.

[30] In the present disclosure, the granular activated carbon is soaked and modified with a sulfuric acid solution and then washed and dried sequentially to obtain the pretreated activated carbon. The present disclosure has no special requirements for the granular activated carbon, and commercial granular activated carbon that is well known to those skilled in the art can be used. In the specific embodiment of the present disclosure, the particle size of the granular activated carbon is preferably 0.2 to 0.5 cm; There are no special requirements on the specific surface area and pore diameter of the granular activated carbon, and those skilled in the art can use granular activated carbon that specific surface area and pore diameter are well known to those skilled in the art. In the specific embodiment of the present disclosure, the larger the specific surface area and pore diameter of the granular activated carbon, the better.

[31] In the present disclosure, the concentration of the sulfuric acid solution is preferably 0.05 to 0.5 mol/L, more preferably 0.05 to 0.4 mol/L, and the soaking time is preferably 15 to 30 minutes, more preferably 20 to 25 minutes, The soaking can be performed at room temperature; the dosage ratio of the granular activated carbon and the sulfuric acid solution is preferably 1g:1-2mL. The present disclosure removes impurities on the surface of the granular activated carbon by soaking in a sulfuric acid solution, improves the surface structure and pore size of the granular activated carbon, and is beneficial to subsequent metal loading and adsorption reactions.

[32] In the present disclosure, the washing is preferably to wash the soaked activated carbon with deionized water and ethanol in sequence, and the number of washings with deionized water and ethanol is preferably 3 times; the drying temperature is preferably 105

-120°C, the drying time is preferably 8-10h; the drying is preferably performed in a constant temperature drying box; after the drying is completed, the obtained pretreated activated carbon is preferably sealed and stored for later use.

[33] After the pretreated activated carbon is obtained, the present disclosure mixes the pretreated activated carbon, the iron salt-nickel salt mixed solution and the reducing agent to perform a reduction reaction to obtain a nickel-iron bimetallic three-dimensional electrode particle filler. In the present disclosure, the solvent of the iron salt-nickel salt mixed solution is water, and the iron salt in the iron salt-nickel salt mixed solution preferably is selected from a group consisting of ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, ferric nitrate, ferrous nitrate and a mixture thereof, specifically preferably FeSQ4+7H20, FeCl::4H;0, Fe(NO3)3:*9H20 or FeCl3+«6H»0O; the nickel salt in the iron salt-nickel salt mixed solution is preferably selected from a group consist of nickel chloride, nickel sulfate, nickel nitrate and a mixture thereof, specifically preferably NiSO4+6H20, Ni(NO3)2#6H20 or NiCl2+6H20; the mass ratio of the iron element and the nickel element in the iron salt-nickel salt mixed solution is preferably 1:2 to 2:1, more preferably 1:1.5 to 1.5:1, most preferably 1:1; the total mass of the iron salt and the nickel salt in the iron salt-nickel salt mixed solution is preferably 1% to 5% of the mass of the pretreated activated carbon, more preferably 2% to 4%.

[34] In the present disclosure, the method for preparing the nickel salt-iron salt mixed solution is preferably: adding the nickel salt and the iron salt to water and stirring until they are completely dissolved.

[35] In the present disclosure, the reducing agent preferably includes NaBH, and/or KBH4; the molar ratio of the total molar amount of iron and nickel in the iron salt-nickel salt mixed solution to the reducing agent is preferably 1:1--2, more preferably it is 1:1.3-

1.5.

[36] In the present disclosure, the process of mixing the pretreated activated carbon, the iron salt-nickel salt mixed solution and the reducing agent preferably includes: mixing the pretreated activated carbon, the iron salt-nickel salt mixed solution, and then under a protective atmosphere and stirring conditions, add the reducing agent solution dropwise to the obtained mixed material liquid; the protective atmosphere is preferably nitrogen, the reducing agent solution is preferably prepared from a reducing agent and water, the reducing agent solution is preferably prepared for immediately use; the concentration of the reducing agent solution is preferably 0.1-0.2 mol/L; the dropping rate is preferably 1 drop/sec. In the specific embodiment of the present disclosure, the reducing agent solution is preferably added dropwise within 10-30 minutes.

[37] In the present disclosure, the temperature of the reduction reaction is preferably room temperature, and the time is preferably 15-30 min, more preferably 20-25 min; the time of the reduction reaction starts from the completion of the dropping of the reducing agent solution. During the reduction reaction process, iron ions and nickel ions are reduced to elemental iron and nickel, and are loaded on the granular activated carbon carrier.

[38] After the reduction reaction is completed, the present disclosure preferably filters the obtained product liquid and dried the obtained solid product to obtain the nickel-iron bimetallic three-dimensional electrode particle filler. In the present disclosure, the drying is preferably vacuum drying, and the temperature of the drying is preferably 80°C.

[39] The present disclosure also provides the nickel-iron bimetallic three-dimensional electrode particle filler prepared by the preparation method described in the above solution, which includes a granular activated carbon carrier and nickel nanoparticles and iron nanoparticles loaded on the granular activated carbon carrier. In the present disclosure, the mass fraction of nickel nanoparticles in the nickel-iron bimetallic three-dimensional electrode particle filler is preferably 1% to 5%, more preferably 1.5% to 4.5%, still more preferably 1.95%, and the mass fraction of iron nanoparticles is preferably 1% to 5%, more preferably 1.1% to 4.5%, further preferably 1.2%; the nickel-iron bimetallic three-dimensional electrode particle filler has a spherical petal-like morphology; the specific surface area of the nickel iron bimetallic three-dimensional electrode particle filler is preferably 500-800m?/g more preferably 600-750m?g, still more preferably

713.6825m?%g, and the micropore area is preferably 400-600m?/g, more preferably 500-590m?/e, and further preferably 582.8164 m?/g, and the external surface area is preferably 100 to 150 mg, more preferably 120 to 140 mg, and still more preferably

130.8661 m¥/g.

[40] The present disclosure also provides the application of the nickel-iron bimetallic three-dimensional electrode particle filler in the electrocatalytic degradation of organic pollutants, specifically the application of electrocatalytic degradation of slightly-polluted organic pollutants in pharmaceuticals and personal care products, and more specifically the application of electrocatalytic degradation of organic pollutants in slightly-polluted organic wastewater, the concentration of organic pollutants in the slightly-polluted organic wastewater is preferably 1 to 5 mg/L, more preferably 2 to 3 mg/L. In the present disclosure, the organic pollutants are preferably sulfonamides, specifically selected from a group consisting of sulfamethizole (SMX), sulfadoxine (SDM), sulfapyridine (SPD), sulfamethoxine (SMM), sulfamethoxine pyrimidine (SMR), sulfadiazine (SDZ), sulfacetamide (SAAM), sulfachloropyridazine (SCP), sulfamethoxidazine (SMP) sulfathiazole (STZ), and a mixture thereof.

[41] In a specific embodiment of the present disclosure, the electrocatalytic degradation method is preferably: adding the nickel-iron bimetallic three-dimensional electrode particle filler into a two-dimensional electrode reactor to form a three-dimensional electrode reactor, and the wastewater is added to the three-dimensional electrolysis reactor for electrocatalytic degradation; the conditions for the electrocatalytic degradation include: the electrolysis voltage is preferably 1-5V, preferably 3-5V, and the electrode plate spacing is preferably 0.5-2.5cm, preferably 2.0cm; the amount ratio of the nickel-iron bimetallic three-dimensional electrode particle filler and the waste water containing organic pollutants is preferably 1-5g:50mL, more preferably 3g:50mL; the positive electrode in the two-dimensional electrode reactor is preferably ruthenium The iridium-titanium coated electrode, and the negative electrode is preferably a graphene electrode.

[42] The nickel-iron bimetallic three-dimensional electrode particle filler provided by the present disclosure has good stability and high reproducibility. In the specific embodiment of the present disclosure, after the first degradation experiment is completed, the particle filler does not need to be regenerated, and the next degradation experiment is directly carried out. The particle filler can be reused more than 50 times.

[43] The technical solutions of the present disclosure will be clearly and completely described below with reference to the embodiments of the present disclosure.

[44] Example 1

[45] Soak the granular activated carbon in 0.05 mol/L dilute sulfuric acid for 15 minutes, filter and wash with deionized water and ethanol solution three times each, dry in a constant temperature drying box and seal for storage for later use;

[46] Weigh FeSO47H20 and NiCl2*6H20 in deionized water, and stir until they are completely dissolved to obtain a nickel salt-iron salt mixture, in which the mass ratio of Ni and Fe elements is 1:1, the total mass of FeSO4+7H,0 and NiCl::6H:0 is 2% of the mass of pretreated activated carbon;

[47] Transfer 100 mL of the nickel salt-iron salt mixture to a three-necked flask containing 10 g of pretreated activated carbon. Under the protection of nitrogen, add the newly prepared NaBH. solution (dilute 0.02mol) at a rate of 1 drop/sec. NaBHs was dissolved in 200 mL of water) into the nickel salt-iron salt mixture, fully stirred, after the dripping, reacted at room temperature for 30 minutes; the reacted material liquid was quickly filtered, and the solid product is dried in a vacuum drying oven at 80 °C, to obtain a nickel-iron bimetallic three-dimensional electrode particle filler.

[48] Fig. 1 is an electron micrograph of the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1. According to Fig. 1, it can be seen that the obtained nickel-iron bimetallic three-dimensional electrode particle filler has a spherical petal-like morphology.

[49] Fig. 2 is the IR spectrum of the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1. According to Fig. 2, it can be seen that iron and nickel are successfully loaded on the surface of the granular activated carbon.

[50] The element composition of the obtained nickel-iron bimetallic three-dimensional electrode particle filler was tested, and the obtained results are shown in Table 1.

[51] Table 1 Elemental composition test results of nickel-iron bimetallic three-dimensional electrode particle filler

To aww

[52] The specific surface area and pore structure of the obtained nickel-iron bimetallic three-dimensional electrode particle filler were tested, and the obtained results are shown in Table 2: 53] Table 2 Test results of specific surface area and pore structure of nickel-iron bimetallic three-dimensional electrode particles BET t-plot t-plot 1.7nm-300n 1.7nm~300n specific micropore apparent m pore BJH mpore surface area specific surface area adsorption cumulative (m%/g) surface area (m%/g) cumulative area of BJH (m%/g) area of pore desorption (m*/g) (mg)

[54] Test example:

[55] The slightly-polluted organic wastewater used in the electrolysis is an aqueous solution of sulfamethizole. The positive electrode of the two-dimensional electrode reactor is a ruthenium-iridium-titanium-coated electrode, and the negative electrode is a graphene electrode. The particle filler prepared in Example 1 is tested for the degradation effect of organic pollutants. .

[56] In order to eliminate the influence of adsorption, particle filler was used to adsorb the aqueous solution of sulfamethizole before the experiment, and the electrolysis experiment was carried out after the adsorption was saturated.

[57] 1. The effect of different cell voltages on the degradation of sulfamethizole

[58] Energy consumption is one of the important factors that restrict the prospect of electrochemical applications. The application of voltage during the degradation process directly determines the consumption of energy consumption. This example tests the effect of different cell voltages on the degradation effect of methadiazole. The steps are as follows:

[59] Add 50ml of the solution containing sulfamethiadiazole into the two-dimensional electrode reactor, and then add the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1, the adding amount is 5g, and the electrolysis voltage is adjusted to IV, 2V, 3V, 4V and SV, the electrode plate spacing is 2cm, the initial concentration of sulfamethizole aqueous solution is Img/L; the removal rate of sulfamethizole at different electrolysis time is tested, and the result is shown in Figure 3.

[60] Figure 3 is a graph showing the effect of different electrolysis voltages on the degradation effect of sulfamethizole. According to Figure 3, it can be seen that the voltage has a great influence on the removal effect of SMT. When the voltage is 1V, the degradation rate within 30 minutes is only 58.3%. When the voltage is increased to 5V, the degradation rate rapidly increases to 96.5%, mainly attributed to the increase of driving force after particle electrode repolarization, the electrolysis voltage is controlled at 1V, which can save energy and prevent the electrode from being broken down by an excessively high voltage.

[61] 2. The effect of different particle filler dosage on the degradation effect of sulfamethizole

[62] Add 50ml of the solution containing sulfamethiadiazole into the two-dimensional electrode reactor, and then add the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1. The added amounts are lg, 2g, 3g, 4g and Sg, respectively, and adjust the electrolysis voltageto SV, the electrode plate spacing was 2cm, and the initial concentration of the sulfamethizole aqueous solution was lmg/L. The removal rate of sulfamethizole at different times was tested, and the results obtained are shown in Figure 4.

[63] Figure 4 is a graph showing the influence of different particle filler dosages on the degradation effect of sulfamethizole. It can be seen from Figure 4 that when the dosage of particle filler is changed from 1g to 5g, the degradation rates of sulfamethizole are 66.6%,

87.5%, 99.9%, 97.5% and 99.3% respectively; with the increase of particle filler, the degradation efficiency has been significantly increased, reaching the maximum at 3g, and the degradation effect of the particle electrode continues to be slightly fluctuated. The main reason is that too many particle electrodes are filled in the electrode plates with a certain distance, which causes the particle electrode to accumulate and congestion, and it is in contact with the positive and negative electrodes. The phase contact increases the short-circuit current, causing the reaction current to fluctuate, which has a slight impact on the degradation effect.

[64] 3. The effect of different electrode plate spacing on the degradation effect of sulfamethizole

[65] Add 50ml of the solution containing sulfamethiadiazole into the two-dimensional electrode reactor, and then add the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1, the addition amount is 5g, the electrolysis voltage is adjusted to 5V, and the electrode plate spacing is respectively 0.5, 1.0 cm, 1.5 cm, 2.0 cm and 2.5 cm, the initial concentration of the sulfamethizole aqueous solution was 1 mg/L, the removal rate of sulfamethizole at different times was tested, and the results obtained are shown in Figure 5.

[66] Figure S is a graph showing the effect of different electrode plate spacing on the degradation effect of sulfamethizole. It can be seen from Figure 5 that when the electrode plate spacing is 0.5cm, the degradation effect is poor. Within 30 minutes, the target pollutant removal rate is only 45.9%. Extreme contact increases the short-circuit current, resulting in a rapid decrease in the reaction current and a decrease in the degradation efficiency of the system. When the distance between the plates is increased, the system gradually recovers its performance. When the distance between the electrodes is lem-2.5cm, the 30min degradation efficiency is 93.8%, 90.0, %, 99.3% and 91.0% respectively. A short distance can reduce material diffusion and promote mass transfer, but a too small distance will cause excessive electric field strength, which may cause a danger of instantaneous discharge of the electrode plate when the power is turned on; under the condition of constant applied voltage, too large distance will also increase the intensity of the electric field between the electrode plates reduces the reaction current, thereby affecting the degree of repolarization of the particle electrode. When the distance between the electrode plates is 2 cm, it is more moderate and the degradation effect is the best. 167] 4. The effect of the initial concentration of sulfamethizole on the degradation effect

[68] Add 50ml of the solution containing sulfamethiadiazole into the two-dimensional electrode reactor, and then add the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1, the adding amount is 5g, the electrolysis voltage is adjusted to 5V, and the electrode plate spacing is 2cm. The initial concentrations of the aqueous solution of sulfamethizole were 1mg/L, 2mg/L, 3mg/L, 4mg/L, Smg/L. The removal rate of sulfamethizole at different times was tested. The results are shown in Figure 6.

[69] Figure 6 is a graph showing the effect of different initial concentrations of sulfamethizole on the degradation effect of sulfamethizole. According to Figure 6, as the concentration of pollutants increases, the degradation efficiency and reaction rate constant of sulfamethadiazole gradually decrease. In theory, increasing the initial concentration of wastewater can reduce the limitation of mass transfer and increase degradation efficient. But the opposite result shows that the degradation of sulfamethizole is not mainly controlled by electrochemical reaction. The increase of initial concentration inhibits the progress of the reaction, mainly because sulfamethizole contains refractory functional groups such as benzene ring, etc. The use of Ni-Fe-GAC particle three-dimensional electrode system to degrade sulfamethiadiazole has little effect. It shows that the three-dimensional particle electrode is more suitable for effective removal of low-concentration pollutants. The concentration of sulfamethiadiazole in natural water is also relatively low, so the method of the present disclosure is suitable for efficient removal of it.

[70] 5. Repeatability test

[71] Add 50ml of the solution containing sulfamethiadiazole into the two-dimensional electrode reactor, and then add the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Example 1, the adding amount is 5g, the electrolysis voltage is adjusted to SV, and the electrode plate spacing is 2cm , The initial concentration of the sulfamethizole aqueous solution is 1mg/L, degrade for 30min, pour out the degraded solution, and test the removal rate of sulfamethizole, then add 50ml of new sulfamethothiazole solution with a concentration of Img / L to the reactor, the degradation experiment was carried out again, and the degradation experiment was repeated 50 times, with each degradation time being 30 minutes.

[72] The experimental results show that the removal rate of sulfamethizole at the first degradation is close to 100%, and after 50 repeated degradations, the removal rate of sulfamethizole is still about 85%, indicating that the particle filler provided by the present disclosure has excellent stability, and good reusability.

[73] Comparative Example

[74] Use granular activated carbon as the particle filler to carry out the sulfamethizole degradation test. The two-dimensional electricity used is the same as in the test example. The specific steps are: add 50ml of the solution containing sulfamethizole to the two-dimensional electrode reactor, and then add granular activated carbon, the addition amount is Sg, the electrolysis voltage is adjusted to 5V, the electrode plate spacing is 2cm, the initial concentration of the sulfamethizole aqueous solution is Img/L, the removal rate of sulfamethizole at different times is tested, and the results are as follows Table 3 shows.

[75] Table 3 Test results of the removal rate of sulfamethizole when granular activated carbon is used as the particle filler 0 ; 0 5 20

[76] According to the data in Table 3, it can be seen that when granular activated carbon is used as the particle filler, the removal rate of sulfamethiadiazole is only about 57% at 30 min. Compared with the comparative example, the nickel-iron bimetallic three-dimensional electrode particle filler provided by the present disclosure has a high removal rate of organic pollutants and a fast removal rate.

[77] Example 2

[78] Other conditions are the same as in Example 1, except that the total mass of FeSO:47H:0 and NiCl2°6H;0 is changed to 3% of the mass of the pretreated activated carbon to obtain a nickel-iron bimetallic three-dimensional electrode particle filler.

[79] Example 3

[80] The other conditions are the same as in Example 1, except that the mass ratio of Ni and Fe in the nickel salt-iron salt mixed solution is changed to 1:1.5, and the total mass of FeSO4¢7H>0 and NiCl12:6H;0 is changed to 5% of the pretreated activated carbon mass, to obtain the nickel-iron bimetallic three-dimensional electrode particle filler.

[81] According to the conditions of the "reproducibility test" under the test example, the nickel-iron bimetallic three-dimensional electrode particle filler prepared in Examples 2 to 3 was subjected to degradation test, and the results showed that the nickel-iron bimetallic three-dimensional electrode particle filler prepared by Examples 2 to 3 degrades sulfamethizole, and the removal rate of the first degradation is more than 98%. After 50 repeated degradations, the removal rate of sulfamethizole remains above 85%.

[82] The above are merely the preferred embodiments of the present disclosure. It should be noted that for those of ordinary skill in the art, improvements and modifications can be made without departing from the principle of the present disclosure, and these improvements and modifications should also be covered within the protection scope of the present disclosure.

Claims

-16 - Conclusions

A production method of bimetallic three-dimensional nickel iron electrode particle filler, the method comprising the steps of: soaking the granular activated carbon in sulfuric acid solution and modifying, washing and drying in this order to obtain pretreated activated carbon; mixing the pretreated activated carbon, the mixed iron salt nickel salt solution and the reducing agent to carry out a reduction reaction to obtain a bimetallic three-dimensional nickel iron electrode particle filler.

The production method according to claim 1, wherein a concentration of the sulfuric acid solution is 0.05 - 0.5 mol/L, and a time of the soaking modification is 15 - 30 min.

The preparation method according to claim 1, wherein the iron salt in the mixed iron salt nickel salt solution is selected from the group consisting of iron (II) chloride, iron (I) chloride, iron (IN) sulfate, iron (Il) sulfate, iron (]) nitrate, nitric acid and a mixture thereof; wherein the nickel salt in the mixed iron salt-mice salt solution is selected from the group consisting of nickel chloride, nickel sulfate, nickel nitrate and a mixture thereof.

The production method according to claim 1 or 3, wherein a mass ratio of the iron element and the nickel element in the mixed iron salt nickel salt solution is 1:2-2:1 1s; wherein the total mass of iron salt and nickel salt in the mixed iron salt nickel salt solution is 1% - 5% of the mass of the pretreated activated carbon.

The preparation method according to claim 1, wherein the reducing agent comprises NaBHy and/or KBH4; wherein a molar ratio of the total molar amount of iron and nickel in the mixed iron salt to nickel salt solution and the total molar amount of the reducing agent is 1:1-2.

-17 -

The preparation method of claim 1, wherein the process of mixing the pretreated activated carbon, the mixed iron salt nickel salt solution and the reducing agent comprises: mixing the pretreated activated carbon, the mixed iron salt nickel salt solution, and then under the protective atmosphere and stirring conditions, adding the reducing agent solution dropwise to the resulting mixture liquid.

The production method according to claim 1, wherein a temperature of the reduction reaction is 20°C and the reduction reaction time is 15-30 min.

A bimetallic three-dimensional nickel iron electrode particle filler prepared by the preparation method according to any one of claims 1 to 7, which comprises a granular activated carbon support and nickel nanoparticles and iron nanoparticles loaded on the granular activated carbon support.

The bimetallic three-dimensional nickel iron electrode particle filler according to claim 8, wherein the mass fraction of nickel nanoparticles in the bimetallic three-dimensional nickel iron electrode particle filler is 1% - 5%, and wherein the mass fraction of the iron nanoparticles is 1% ~ 5%.

Use of the bimetallic three-dimensional nickel iron electrode particle filler according to claim 8 or 9 in electrocatalytic degradation of organic pollutants.