Adsorption particle electrode for wastewater and waste liquid treatment and preparation method thereof

Abstract

The invention belongs to the technical field of wastewater treatment, and particularly relates to an adsorption particle electrode for wastewater and waste liquid treatment and a preparation method thereof. The preparation method comprises the following steps: adding a zinc salt, a vanadium salt, a scandium salt and cetyltrimethylammonium bromide into water, stirring, adjusting the pH value at 70-80 DEG C, continuously stirring, filtering, drying and calcining to obtain modified mesoporous zinc oxide; and dispersing the modified mesoporous zinc oxide in water, adding the composite aerogel, soaking, filtering, washing, drying and grinding to obtain the adsorption particle electrode. The adsorption particle electrode prepared by the invention can be used for degrading printing and dyeing wastewater, and has the excellent performances of high degradation rate, high degradation speed, reusability and the like.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to an adsorption particle electrode for wastewater and waste liquid treatment and its preparation method. Background Technology

[0002] Against the backdrop of rapid industrialization and urbanization, the output of domestic wastewater and industrial wastewater in urban areas continues to rise. Among them, dyeing and printing wastewater, containing complex and recalcitrant pollutants such as dyes and auxiliaries, has become a major challenge in wastewater treatment. If dyeing and printing wastewater is discharged directly without effective or thorough treatment, it will cause serious damage to aquatic ecosystems and trigger a water resource crisis. Currently, conventional water treatment technologies are mainly divided into physical, chemical, and biological methods. Physical methods have limited effectiveness in removing dissolved pollutants from dyeing and printing wastewater; chemical methods, while capable of degrading some pollutants, may produce secondary pollution and are costly; biological methods are affected by the biodegradability of the wastewater and are inefficient in treating recalcitrant dyeing and printing wastewater. Overall, conventional technologies for treating dyeing and printing wastewater suffer from problems such as poor removal efficiency or excessively high costs.

[0003] Electrochemical catalysis is an emerging wastewater and waste liquid treatment technology with advantages such as convenient operation, high cost-effectiveness, and environmental friendliness. With technological advancements, three-dimensional electrode reactors have been formed by filling them with granular electrodes, building upon traditional two-dimensional electrode reactors. Under the influence of an electric field, numerous microelectrodes are generated, increasing the electrolytic cell area ratio and electrocatalytic active sites, shortening the migration distance of reactants, and increasing mass transfer rates, thus effectively improving current efficiency and treatment performance. Commonly used granular electrodes include activated carbon, metals, and their oxide particles. However, these materials suffer from drawbacks such as low conductivity, low electrochemical oxidation efficiency, and poor acid and alkali resistance, easily leading to problems like low current efficiency, insufficient stability, and performance degradation in the electrode reactor. Therefore, it is necessary to composite or modify these materials to achieve higher electrocatalytic performance and chemical stability, enabling better application in wastewater and waste liquid treatment. Summary of the Invention

[0004] The first objective of this invention is to provide a method for preparing an adsorption particle electrode for wastewater and waste liquid treatment.

[0005] The second objective of this invention is to provide an adsorption particle electrode for wastewater and waste liquid treatment, which has a high wastewater degradation rate, fast reaction rate, and stable reusability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing an adsorption particle electrode for wastewater and waste liquid treatment includes the following steps: (1) Add zinc salt, vanadium salt, scandium salt and hexadecyltrimethylammonium bromide to water and stir. Adjust the pH at 70-80℃ and continue stirring. After filtration, drying and calcination, modified mesoporous zinc oxide is obtained. (2) The modified mesoporous zinc oxide is dispersed in water to obtain a dispersion; the composite aerogel is soaked in the dispersion for 20-30 hours, and then filtered, washed, dried and ground to obtain the adsorption particle electrode.

[0007] Further, the molar ratio of zinc salt, vanadium salt, scandium salt and hexadecyltrimethylammonium bromide in step (1) is 1:(0.05-0.15):(0.05-0.1):(0.3-0.5).

[0008] Furthermore, the pH value adjusted in step (1) is 7.5-8.5; the stirring time is 1-3 hours.

[0009] Furthermore, the calcination temperature in step (1) is 500-700℃ and the time is 3-5h.

[0010] Furthermore, the composite aerogel described in step (2) is prepared by the following process: (a) Add nickel salt, iron salt and urea to water, adjust the pH to 9-12 and carry out hydrothermal reaction, filter and dry to obtain nickel-iron hydrotalcite; (b) The nickel-iron hydrotalcite and cerium sulfide were dispersed in N-methylpyrrolidone, polypyrrole was added and stirred to react, and the composite aerogel was obtained after freeze-drying.

[0011] Further, in step (a), the molar ratio of nickel salt, iron salt and urea is 1:(3-4):(12-24); the hydrothermal reaction temperature is 130-160℃ and the time is 8-12h.

[0012] Further, in step (b), the mass ratio of nickel-iron hydrotalcite, cerium sulfide, and polypyrrole is 10:0.5-1.5:1-2; and the stirring reaction time is 1-5 hours.

[0013] Further, the mass ratio of the modified mesoporous zinc oxide to the composite aerogel in step (2) is 1:8-10.

[0014] An adsorption particle electrode for wastewater and waste liquid treatment is prepared by the above-described method for preparing an adsorption particle electrode for wastewater and waste liquid treatment.

[0015] The beneficial technical effects of this invention are as follows: 1. This invention loads scandium-vanadium bimetallic doped mesoporous zinc oxide into a particulate electrode. Zinc oxide can generate hydroxyl radicals through electrocatalysis and also generate electron-hole pairs under photocatalysis, forming superoxide radicals and hydroxyl radicals respectively, which can decompose pollutants in water into CO2 and H2O. Furthermore, the mesoporous structure has a large specific surface area, providing abundant active sites and enhancing the adsorption capacity for pollutants, achieving synergistic adsorption and photocatalytic treatment of wastewater. However, zinc oxide has a narrow photoresponse range and is prone to photocorrosion during cycling. This invention utilizes scandium-vanadium co-doping to modify it, which can regulate the band structure of zinc oxide, expand its photoresponse range, and improve the degradation rate.

[0016] 2. This invention uses a composite aerogel of nickel-iron hydrotalcite and cerium sulfide as a carrier. Nickel-iron hydrotalcite has a two-dimensional layered structure and abundant active sites, which can adsorb pollutants in water through interlayer anion exchange and catalytically degrade them through the redox reaction of nickel and iron ions. Cerium sulfide has good conductivity and redox properties. When combined with nickel-iron hydrotalcite, it can improve the electron transport rate, enhance catalytic activity, and form sulfur vacancies, inhibiting the attachment and growth of microorganisms and maintaining the long-term stability of the particulate electrode. The aerogel has a stable porous network structure, which can not only provide adsorption channels but also ensure the cycling stability of the particulate electrode. Attached Figure Description

[0017] Figure 1 This is a SEM image of the adsorption particle electrode prepared in Example 1 of the present invention; Figure 2 This is a comparison chart showing the performance of the adsorbent particle electrodes prepared in Examples 1-3 and Comparative Examples 1-3 in degrading Rhodamine B. Detailed Implementation

[0018] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0019] (a) Preparation example Preparation Example 1 Preparation Example 1 provides a composite aerogel, which is prepared by the following process: (a) Nickel nitrate, ferric nitrate, urea and water were ultrasonically dispersed in water according to the ratio of nickel nitrate, ferric nitrate, urea and water: 1 mmol: 3 mmol: 18 mmol: 45 mL. The pH was adjusted to 10 using 18 wt% ammonia water. The mixture was then hydrothermally reacted at 140 °C for 10 h. After filtration and drying, nickel-iron hydrotalcite was obtained. (b) Nickel-iron hydrotalcite, cerium sulfide, polypyrrole and N-methylpyrrolidone were ultrasonically dispersed in N-methylpyrrolidone according to the ratio of nickel-iron hydrotalcite, cerium sulfide, polypyrrole and N-methylpyrrolidone 10mg:1mg:1mg:50mL, polypyrrole was added and mixed evenly, stirred and reacted for 3h, and then freeze-dried to obtain composite aerogel.

[0020] Preparation Example 2 Preparation Example 2 provides a composite aerogel, which is prepared by the following process: (a) Nickel nitrate, ferric nitrate, urea and water were ultrasonically dispersed in water according to the ratio of nickel nitrate, ferric nitrate, urea and water: 1 mmol: 3 mmol: 12 mmol: 40 mL. The pH was adjusted to 9 with 15 wt% ammonia water. The mixture was then hydrothermally reacted at 130 °C for 8 h. After filtration and drying, nickel-iron hydrotalcite was obtained. (b) Nickel-iron hydrotalcite, cerium sulfide, polypyrrole and N-methylpyrrolidone were ultrasonically dispersed in N-methylpyrrolidone according to the ratio of nickel-iron hydrotalcite, cerium sulfide, polypyrrole and N-methylpyrrolidone 10mg:0.5mg:1mg:40mL, polypyrrole was added and mixed evenly, stirred and reacted for 1h, and then freeze-dried to obtain composite aerogel.

[0021] Preparation Example 3 Preparation Example 3 provides a composite aerogel, which is prepared by the following process: (a) Nickel nitrate, ferric nitrate, urea and water were ultrasonically dispersed in water according to the ratio of nickel nitrate, ferric nitrate, urea and water: 1 mmol: 4 mmol: 24 mmol: 50 mL. The pH was adjusted to 12 with 20 wt% ammonia water. The mixture was then hydrothermally reacted at 160 °C for 12 h. After filtration and drying, nickel-iron hydrotalcite was obtained. (b) According to the ratio of nickel-iron hydrotalcite, cerium sulfide, polypyrrole and N-methylpyrrolidone, 10 mg: 1.5 mg: 2 mg: 60 mL, nickel-iron hydrotalcite and cerium sulfide were ultrasonically dispersed in N-methylpyrrolidone, polypyrrole was added and mixed evenly, the mixture was stirred and reacted for 5 h, and then freeze-dried to obtain composite aerogel.

[0022] Preparation Example 4 Preparation Example 4 provides a composite aerogel, which differs from Preparation Example 1 only in that cerium sulfide is omitted in step (b).

[0023] (II) Implementation Examples Example 1 Example 1 provides a method for preparing an adsorption particle electrode for wastewater and waste liquid treatment, comprising the following steps: (1) According to the ratio of zinc nitrate, vanadium nitrate, scandium nitrate, hexadecyltrimethylammonium bromide and water, 1 mol: 0.1 mol: 0.08 mol: 0.4 mol: 13 L, zinc nitrate, vanadium nitrate, scandium nitrate and hexadecyltrimethylammonium bromide were added to water and stirred at 70 °C to dissolve. The pH was adjusted to 8 with 1 mol / L lithium hydroxide solution and stirred for 2 h. The solid substance was obtained by filtration, dried and calcined at 600 °C for 4 h to obtain modified mesoporous zinc oxide. (2) According to the ratio of modified mesoporous zinc oxide to composite aerogel and water, 1 mg: 9 mg: 1.2 mL, the modified mesoporous zinc oxide was added to water and ultrasonically dispersed evenly to obtain a dispersion. The composite aerogel of Preparation Example 1 was placed in the dispersion and soaked for 25 h. The solid material was filtered out, washed repeatedly and dried. The dried solid material was ground and passed through a 100-mesh sieve to obtain the final product.

[0024] This embodiment also provides an adsorption particle electrode for wastewater and waste liquid treatment, prepared by the above-described method; the scanning electron microscope image of the adsorption particle electrode is shown below. Figure 1 As shown.

[0025] Example 2 Example 2 provides a method for preparing an adsorption particle electrode for wastewater and waste liquid treatment, comprising the following steps: (1) According to the ratio of zinc nitrate, vanadium nitrate, scandium nitrate, hexadecyltrimethylammonium bromide and water, 1 mol: 0.05 mol: 0.05 mol: 0.3 mol: 10 L, zinc nitrate, vanadium nitrate, scandium nitrate and hexadecyltrimethylammonium bromide were added to water and stirred to dissolve at 70 °C. The pH was adjusted to 7.5 with 1 mol / L lithium hydroxide solution and stirred for 1 h. The solid substance was filtered and dried and calcined at 500 °C for 3 h to obtain modified mesoporous zinc oxide. (2) According to the mass ratio of modified mesoporous zinc oxide to composite aerogel of 1:8, the modified mesoporous zinc oxide was added to water and ultrasonically dispersed evenly to obtain a dispersion. The composite aerogel of Preparation Example 2 was soaked in the dispersion for 20 hours, the solid material was filtered out, washed repeatedly and dried, and the dried solid material was ground and passed through a 100-mesh sieve to obtain the final product.

[0026] This embodiment also provides an adsorption particle electrode for wastewater and waste liquid treatment, which is prepared by the above preparation method.

[0027] Example 3 Example 3 provides a method for preparing an adsorption particle electrode for wastewater and waste liquid treatment, comprising the following steps: (1) According to the ratio of zinc nitrate, vanadium nitrate, scandium nitrate, hexadecyltrimethylammonium bromide and water, 1 mol: 0.15 mol: 0.1 mol: 0.5 mol: 16 L, zinc nitrate, vanadium nitrate, scandium nitrate and hexadecyltrimethylammonium bromide were added to water and stirred to dissolve at 80 °C. The pH was adjusted to 8.5 with 1 mol / L lithium hydroxide solution and stirred for 3 h. The solid substance was filtered and dried and calcined at 700 °C for 5 h to obtain modified mesoporous zinc oxide. (2) According to the mass ratio of modified mesoporous zinc oxide to composite aerogel of 1:10, the modified mesoporous zinc oxide was added to water and ultrasonically dispersed evenly to obtain a dispersion. The composite aerogel of Preparation Example 3 was soaked in the dispersion for 30 hours, the solid material was filtered out, washed repeatedly and dried, and the dried solid material was ground and passed through a 100-mesh sieve to obtain the final product.

[0028] This embodiment also provides an adsorption particle electrode for wastewater and waste liquid treatment, which is prepared by the above preparation method.

[0029] (III) Comparative Example Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that: in step (1) when preparing modified mesoporous zinc oxide, vanadium nitrate and scandium nitrate are not added, that is, mesoporous zinc oxide is used instead of modified mesoporous zinc oxide.

[0030] Comparative Example 2 Comparative Example 2 is basically the same as Example 1, except that: in step (1) when preparing modified mesoporous zinc oxide, vanadium nitrate and scandium nitrate are not added, and in step (2) the dispersion is added in an equal molar amount of vanadium nitrate and scandium nitrate.

[0031] Comparative Example 3 Comparative Example 3 is basically the same as Example 1, except that the composite aerogel in step (2) is replaced with the composite aerogel of Preparation Example 4.

[0032] (iv) Test Examples The adsorption particle electrodes prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests.

[0033] Pollutant degradation test: Simulated wastewater was prepared using 500 mL of Rhodamine B with an initial concentration of 25 mg / L. Ti plates were used as cathodes and RuO2 / Ti plates as anodes, with working areas of 3 cm x 5 cm in the solution and a 4 cm gap between the cathode and anode. 0.05 mol of sodium sulfate was added as the electrolyte, and 10 g / L of each adsorbed particle electrode was added. A 0.5 V bias voltage was applied, and the electrode was vertically irradiated using a xenon lamp with an AM1.5G filter. Absorbance was measured every 10 minutes using a UV-Vis spectrophotometer, and the degradation rate was calculated. Degradation rate = (1 - A) / (25 mg / L) * ...t / A0)×100%, where A0 is the absorbance of the solution before illumination, A t The absorbance of the solution at illumination time t is given; the degradation rate after 1 hour is calculated, and the results are shown in Table 1 and [Table data missing]. Figure 2 .

[0034] Stability test: To examine the reusability of the adsorption particle electrodes prepared in Examples 1-3 and Comparative Examples 1-3, after each degradation test, each adsorption particle electrode was taken out, dried in a forced-air drying oven, and reused. The degradation rate of the organic pollutant Rhodamine B was calculated on the 10th use. The results are shown in Table 1.

[0035] Table 1. Degradation and stability test results of adsorbed particle electrodes As shown in Table 1, the adsorption particle electrodes prepared in Examples 1-3 of this invention have excellent properties such as high degradation rate, fast degradation speed and reusability when used for the removal of Rhodamine B in wastewater.

[0036] Compared to Example 1, Comparative Example 1 replaced the scandium-vanadium bimetallic doped mesoporous zinc oxide with unmodified mesoporous zinc oxide, Comparative Example 2 directly mixed mesoporous zinc oxide with scandium oxide and vanadium oxide, and Comparative Example 3 omitted cerium sulfide in the composite aerogel. The degradation effects and the 10th degradation rate of Comparative Examples 1-3 all decreased to varying degrees. Specific analysis shows that: on the one hand, the present invention loads scandium-vanadium bimetallic doped mesoporous zinc oxide in the particle electrode. Zinc oxide can generate hydroxyl radicals through electrocatalysis and can also generate electron-hole pairs under photocatalysis, forming superoxide radicals and hydroxyl radicals respectively, which can decompose pollutants in water into CO2 and H2O; moreover, the mesoporous structure has a large specific surface area, which can provide abundant active sites, enhance the adsorption capacity for pollutants, and realize the adsorption and photoelectrochemical synergistic catalytic treatment of wastewater and waste liquid. However, zinc oxide has a narrow photoresponse range and is prone to photocorrosion during cycling. This invention utilizes scandium-vanadium co-doping to modify it, which can regulate the band structure of zinc oxide, expand its photoresponse range, and improve the degradation rate. On the other hand, this invention uses nickel-iron layered double hydroxide (TLD) and cerium sulfide composite aerogel as a carrier. Nickel-iron TLD has a two-dimensional layered structure and abundant active sites, which can adsorb pollutants in water through interlayer anion exchange and catalytically degrade them through the redox reaction of nickel and iron ions. Cerium sulfide has good conductivity and redox properties. When combined with nickel-iron TLD, it can improve the electron transport rate, enhance catalytic activity, and form sulfur vacancies, inhibiting the attachment and growth of microorganisms and maintaining the long-term stability of the particulate electrode. The aerogel has a stable porous network structure, which not only provides adsorption channels but also ensures the cycling stability of the particulate electrode.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A method for preparing an adsorption particle electrode for wastewater and waste liquid treatment, characterized in that, Includes the following steps: (1) Add zinc salt, vanadium salt, scandium salt and hexadecyltrimethylammonium bromide to water and stir. Adjust the pH at 70-80℃ and continue stirring. After filtration, drying and calcination, modified mesoporous zinc oxide is obtained. (2) The modified mesoporous zinc oxide is dispersed in water to obtain a dispersion; The composite aerogel was soaked in the dispersion for 20-30 hours, and then filtered, washed, dried and ground to obtain the adsorption particle electrode.

2. The method for preparing the adsorption particle electrode for wastewater and waste liquid treatment according to claim 1, characterized in that, The molar ratio of zinc salt, vanadium salt, scandium salt and hexadecyltrimethylammonium bromide in step (1) is 1:(0.05-0.15):(0.05-0.1):(0.3-0.5).

3. The method for preparing the adsorption particle electrode for wastewater and waste liquid treatment according to claim 1, characterized in that, The pH value adjusted in step (1) is 7.5-8.5; the stirring time is 1-3 hours.

4. The method for preparing the adsorption particle electrode for wastewater and waste liquid treatment according to claim 1, characterized in that, The calcination temperature in step (1) is 500-700℃ and the time is 3-5h.

5. The method for preparing an adsorption particle electrode for wastewater and waste liquid treatment according to claim 1, characterized in that, The composite aerogel described in step (2) is prepared by the following process: (a) Add nickel salt, iron salt and urea to water, adjust the pH to 9-12 and carry out hydrothermal reaction, filter and dry to obtain nickel-iron hydrotalcite; (b) The nickel-iron hydrotalcite and cerium sulfide were dispersed in N-methylpyrrolidone, polypyrrole was added and stirred to react, and the composite aerogel was obtained after freeze-drying.

6. The method for preparing the adsorption particle electrode for wastewater and waste liquid treatment according to claim 5, characterized in that, The molar ratio of nickel salt, iron salt and urea in step (a) is 1:(3-4):(12-24); the hydrothermal reaction temperature is 130-160℃ and the time is 8-12h.

7. The method for preparing an adsorption particle electrode for wastewater and waste liquid treatment according to claim 5, characterized in that, The mass ratio of nickel-iron hydrotalcite, cerium sulfide and polypyrrole in step (b) is 10:0.5-1.5:1-2; the stirring reaction time is 1-5 h.

8. The method for preparing an adsorption particle electrode for wastewater and waste liquid treatment according to claim 1, characterized in that, The mass ratio of the modified mesoporous zinc oxide to the composite aerogel in step (2) is 1:8-10.

9. An adsorption particle electrode for wastewater and waste liquid treatment, characterized in that, It is prepared by the method for preparing adsorption particulate electrode for wastewater and waste liquid treatment according to any one of claims 1-8.

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