Advanced photocatalytic oxidation efficient water treatment method for industrial wastewater treatment

Abstract

The invention discloses an advanced photocatalytic oxidation efficient water treatment method for industrial wastewater treatment, and belongs to the technical field of sewage treatment. The high-efficiency water treatment method mainly aims at industrial production wastewater, especially high-COD and high-salt-content production wastewater, can realize rapid and high-efficiency removal of COD in the wastewater, and can adjust the composition of the catalyst, accelerate the reaction rate, improve the removal effect and reduce the reaction cost according to actual needs. According to the method, a combined process of an ultraviolet lamp, an oxidizing agent and a catalyst is adopted, specific photocatalytic oxidation conditions are determined according to the water treatment capacity, it is ensured that the COD concentration is rapidly, efficiently and low-cost reduced within a short time, and the emission or further treatment standard is met. The method has the characteristic of universality and can be applied to treatment of industrial wastewater in various industries such as chemical industry, pharmacy and photovoltaic industry, the oxidizing agent and the catalyst are cheap and easy to obtain, secondary pollution is avoided, and the method is an effective method for realizing rapid and efficient treatment of high-COD-concentration and high-salt-content industrial wastewater.

Description

Technical Field

[0001] The present application belongs to the technical field of industrial wastewater treatment, and specifically relates to a MPUV / H2O2 advanced photocatalytic oxidation high-efficiency water treatment method for industrial wastewater treatment. Background Art

[0002] Traditional water treatment processes mainly remove suspended solids, colloids, bacteria, etc. in water, but are not very effective in removing dissolved organic matter in water. Photocatalytic oxidation technology is one of the emerging advanced oxidation technologies. It can directly mineralize and decompose a variety of organic pollutants into CO2 or reduce toxicity through oxidation. It has the advantages of high treatment efficiency, wide application range, and more thorough destruction of toxic pollutants. It has become a hot spot in the research and application fields of industrial wastewater treatment.

[0003] In the related art, for example, the Chinese invention patent with publication number CN1164462268A records a method for promoting the degradation of antibiotic pollutants in a UV / H2O2 system. The method adds soluble bromide to the UV / H2O2 system, and the bromide ions participate in the reaction under ultraviolet light to form new bromine free radicals to increase the treatment efficiency of antibiotics. Although the invention improves the removal efficiency of antibiotics, bromide introduces new pollutants, bromide ions, which are difficult to remove and increase the cost of sewage treatment. Another example is the Chinese invention patent with publication number CN110759460A, which discloses a three-stage UV / O3 / H2O2 advanced oxidation system for sewage treatment, which includes an ozone pre-oxidation tank, an advanced oxidation reaction tank, and a deep advanced oxidation reaction tank connected in sequence, an inlet pipe connected to the ozone pre-oxidation tank, an outlet pipe connected to the deep advanced oxidation reaction tank, and an O3 / H2O2 oxidation reactor arranged in the ozone pre-oxidation tank, and a UV / O3 / H2O2 oxidation reactor arranged in the advanced oxidation reaction tank and the deep advanced oxidation reaction tank. The invention introduces O3 and H2O2 to treat pollutants in a coordinated manner, which has the advantages of improving the pollutant removal effect and not introducing new pollutants. However, the production of O3 requires O2 and an ozone generator, which undoubtedly increases the cost of water treatment. Another example is the Chinese invention patent with publication number CN114634265A, which discloses a photo-Fenton process for the treatment of refractory organic wastewater, including firstly adjusting the pH value of raw water to 3-5 by gravity to a regulating tank, and then entering a high-efficiency mixing tank; in the high-efficiency mixing tank, the reagent and wastewater are fully mixed under the action of cyclonic aeration stirring and enter the oxidation reaction zone; the reagent is evenly mixed in the oxidation reaction zone, and the chain reaction between the divalent iron ions and H2O2 in the oxidation reaction zone catalyzes the generation of ·OH; most of the divalent iron ions have been converted into trivalent iron ions, and then the reflux system flows through the UV photocatalytic reactor; under the excitation of UV high-intensity light quanta, the trivalent iron ions are converted back into divalent iron ions, and then returned to the second step for repeated use; after neutralization, the wastewater enters a high-density sedimentation tank for solid-liquid separation, and finally the effluent meets the discharge standards. This invention increases the generation and utilization rate of hydroxyl radicals by repeatedly utilizing iron ions, but Fe 2+ The introduction will bring a large amount of chemical sludge, increasing the cost of sludge disposal.

[0004] The above-mentioned prior art has improved the UV / H2O2 system and has also achieved a certain degree of efficiency improvement, but the improvement method faces the problems of increased cost and secondary pollution, which is not desirable for the treatment manufacturer. Therefore, how to quickly reduce the COD of industrial wastewater without significantly increasing costs and generating secondary pollution, and how to achieve a universal process applicable to various types of wastewater are still urgent problems to be solved in industrial wastewater treatment. Summary of the invention

[0005] This application aims at the treatment of production wastewater in various industries such as chemical, pharmaceutical, photovoltaic, etc., especially the rapid removal of high-concentration COD, and provides an MPUV / H2O2 advanced photocatalytic oxidation high-efficiency water treatment method for industrial wastewater treatment.

[0006] In order to solve the above problems, the technical solutions adopted in this application are as follows:

[0007] The present application provides an advanced photocatalytic oxidation high-efficiency water treatment method for industrial wastewater treatment. The high-efficiency water treatment method determines the selection of ultraviolet lamps, the amount of oxidant and the amount of catalyst according to the amount of water to be treated. The specific steps are as follows:

[0008] S1: Determine the COD concentration of the industrial wastewater to be treated and adjust its pH value to 4-6;

[0009] S2: Add oxidant to the industrial wastewater to be treated, and the amount of oxidant added is determined according to the amount of water to be treated;

[0010] S3: Adding catalyst Fe to the wastewater to be treated 2+ x Fe 3+ y Cu 2+ 1-x-y , the dosage is determined according to the amount of water treated, and the x and y values ​​are adjusted according to the reaction requirements;

[0011] S4: Turn on the UV lamp to start the photocatalytic oxidation reaction.

[0012] Furthermore, the ultraviolet lamp is a medium-pressure ultraviolet lamp with a wide range of ultraviolet emission wavelengths and adjustable actual working power. The ultraviolet emission wavelength is 200-400nm and the working power is between 300w and 1000w.

[0013] Furthermore, the oxidant refers to one or more of persulfate, hydrogen peroxide, hypochlorite, etc.

[0014] Furthermore, the dosage of the oxidant is determined according to the amount of treated water, and the dosage of the oxidant is 0.1-10wt% of the amount of treated water, preferably 0.5-5wt%; the oxidant can generate strong oxidizing groups under ultraviolet light, and these groups can undergo redox reactions with organic matter in the wastewater to achieve the purpose of decomposing the organic matter.

[0015] Furthermore, the catalyst Fe 2+ x Fe 3+ y Cu 2+ 1-x-y The x and y values ​​are 0 to 1, which means that Cu 2+ , Fe2+ , Fe 3 + A solid catalyst, catalyst solution or catalyst dispersion containing one or more ions in the catalyst can promote the rate at which the oxidant produces oxidative free radicals after being excited by ultraviolet light, thereby improving the photocatalytic oxidation activity and enhancing the removal rate of organic matter in the wastewater; the x and y values ​​can be adjusted according to actual needs to change the reaction effect. Increasing the x and y values ​​can improve the COD removal effect, that is, pursuing a high COD removal level, controlling x at 0.3-0.8, and controlling y at 0-0.1; reducing the x and y values ​​can improve the reaction rate, that is, pursuing a reaction speed, controlling x at 0-0.3, and controlling y at 0-0.1. After optimization, the reaction rate can be accelerated and the COD removal effect can be improved at the same time. At this time, x=0.45 and y=0.075.

[0016] Furthermore, the dosage of the catalyst is determined according to the amount of water to be treated, and the amount of the catalyst is 0.01 to 1 wt% of the amount of water to be treated, preferably 0.05 to 0.5 wt%.

[0017] Furthermore, the COD concentration in the industrial wastewater to be treated is between 1000 mg / L and 30000 mg / L, or higher.

[0018] Furthermore, before the photocatalytic oxidation reaction, the pH value of the industrial wastewater to be treated is adjusted to between 4 and 6, and there is no need to adjust the pH during the reaction.

[0019] Furthermore, during the photocatalytic oxidation reaction, the reaction temperature is between 20 and 60° C. Under this temperature condition, both the rate and efficiency of the advanced oxidation reaction can be taken into account; generally, the reaction can be carried out at room temperature.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] (1) The present application provides a MPUV / H2O2 advanced photocatalytic oxidation high-efficiency water treatment method for industrial wastewater treatment. The applicant has proposed a method for controlling advanced oxidation conditions according to different influent indicators by exploring the degradation law of organic matter based on a large amount of actual industrial wastewater treatment work, so that the advanced oxidation process can be carried out efficiently, and the reaction time of several hours can be shortened to less than 15 minutes. Depending on the COD concentration of the influent, ultraviolet irradiation, addition of oxidants, and addition of catalysts are selectively used for treatment. It has general advantages in treating sudden emergency water pollution and high water quality requirements.

[0023] (2) This application provides a MPUV / H2O2 advanced photocatalytic oxidation high-efficiency water treatment method for industrial wastewater treatment, the catalyst Fe 2+ x Fe 3+ y Cu 2+ 1-x-y It is a multi-proportion combination catalyst. The x and y values ​​are adjusted according to actual needs to achieve rapid COD removal and high-level COD removal without causing secondary pollution. The cost is low. After the reaction is completed, it can be recovered by adjusting the pH, and the recovery rate is above 99%. This takes into account the multiple requirements of rapid and efficient reaction, no significant increase in cost, and no secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a comparison chart of the treatment effects of Example 1.

[0025] Figure 2 This is a comparison chart of the treatment effects of Example 2.

[0026] Figure 3 It is a comparison chart of the treatment effects of Example 3. DETAILED DESCRIPTION

[0027] The present application is further described below in conjunction with specific embodiments.

[0028] The high-efficiency water treatment method of the present invention adopts a combination of medium-pressure ultraviolet lamp irradiation, oxidant and catalyst to carry out advanced oxidation, and the catalyst is composed of a single Fe 2+ The composition is extended to Fe 2+ x Fe 3+ y Cu 2+ 1-x-y In combination, the new catalyst can shorten the reaction time of several hours to only 15 minutes and improve the removal effect of pollutants. In response to the problem of which catalyst to use for treatment, a new method with almost zero cost, recyclability and no secondary pollution is provided. According to the different COD concentration, water volume and treatment requirements of the treated wastewater, the specific catalyst Fe is selected and set. 2+ x Fe 3+ y Cu 2+ 1-x-y Composition ratio, dosage and oxidant dosage. After ultraviolet irradiation, the specific composition catalyst Fe 2+ x Fe 3+ y Cu 2+ 1-x-yIt promotes the rapid reaction of hydrogen peroxide to produce a large number of free radicals, effectively improving the removal efficiency of COD in wastewater. Further adjusting the pH of the treated wastewater can realize the recovery of the catalyst, which can be reused after simple cleaning, and the catalyst recovery rate reaches more than 99%. Through the method of this application, when facing the treatment of industrial wastewater with high COD concentration, the amount of oxidant is determined according to the COD concentration and the amount of water to be treated, and the catalyst Fe is adjusted according to the treatment requirements. 2+ x Fe 3+ y Cu 2+ 1-x-y The composition ratio can achieve a two-way selection of COD removal speed and removal effect. Rapid COD removal has greater advantages for emergency water pollution incidents, and high COD removal levels are more competitive for wastewater treatment with high water quality requirements.

[0029] Fe of the present invention 2+ x Fe 3+ y Cu 2+ 1-x-y Contains Cu 2+ , Fe 2+ , Fe 3+ A solid catalyst, catalyst solution or catalyst dispersion containing one or more ions in the catalyst, etc., the following embodiment 1 uses a solid catalyst, 0.15g of ferric chloride, 4g of ferrous sulfate heptahydrate, and 0.32g of cupric chloride are weighed, respectively, mixed and dissolved, and added to 1L of the water sample to be treated; the dosage is 0.1wt% of the treated water volume, wherein the dosage = the total mass of the catalyst metal ions / the treated water volume, and the total mass of the catalyst metal ions can be calculated according to the dosage. Example 2 uses a catalyst solution, in which the mass fractions of ferric chloride, ferrous sulfate heptahydrate and cupric chloride are 7.5%, 2.2% and 26.7% respectively, and 100mL of the above catalyst solution is added to 10L of the water sample to be treated.

[0030] Example 1

[0031] This embodiment provides an efficient treatment method for wastewater containing dichlorophenoxyacetic acid (2,4-D), which specifically includes:

[0032] S1: Determine the COD content of the 2,4-D wastewater, and the measured COD=2500 mg / L;

[0033] S2: Take 1L of the 2,4-D wastewater, adjust the pH to 4.0, and then add it to the reactor;

[0034] S3: Take 10 mL of hydrogen peroxide (wt=35%), i.e., the dosage is 1 wt% of the treated water, and add it to the above reactor, and stir it magnetically;

[0035] S4: Weigh a certain amount of catalyst Fe 2+ 0.8 Fe 3+ 0.05 Cu 2+ 0.15 , and then added to the above reaction solution after being completely dissolved, so that the catalyst Fe 2+ 0.8 Fe 3+ 0.05 Cu 2+ 0.15 The total mass concentration of metal ions in the wastewater is 0.1wt%;

[0036] S5: Turn on the UV lamp, adjust the lamp power to 1000W, and the reaction begins;

[0037] S6: taking the above reaction water samples regularly during the reaction process to detect the COD concentration;

[0038] S7: After the above reaction is carried out for 15 minutes, the UV lamp is turned off to stop the reaction;

[0039] S8: Pour out the wastewater after the reaction, adjust the pH to 6.5-8, and let it stand for precipitation;

[0040] S9: Pour out the supernatant after standing, take a sample to test COD, wash the precipitate, filter and dry to obtain the original catalyst.

[0041] Comparative Example 1

[0042] For comparison, other treatment conditions are the same as those in Example 1, and the same wastewater is treated, except that the ferrous sulfate catalyst added in S4 is directly subjected to UV / H2O2 reaction, and in S8, the wastewater after the reaction is poured out and allowed to stand, and COD is sampled and tested, and the reaction is terminated. Figure 1 .

[0043] Example 2

[0044] This embodiment provides an efficient treatment method for wastewater containing clethodim, which specifically includes:

[0045] S1: Determine the COD content of the clethodim wastewater, and the measured COD=3600 mg / L;

[0046] S2: Take 10 L of the clethodim wastewater, adjust the pH to 4.5, and then add it into the reactor;

[0047] S3: Take 150 mL of hydrogen peroxide (wt=35%), i.e., the dosage is 1.5 wt% of the treated water, and add it to the above reactor, and stir it magnetically;

[0048] S4: Weigh a certain amount of catalyst Fe 2+ 0.1 Fe 3+ 0.05 Cu 2+ 0.85 , and then added to the above reaction solution after being completely dissolved, so that the catalyst Fe 2+ 0.1 Fe 3+ 0.05 Cu 2+ 0.85 The total mass concentration of metal ions in the wastewater is 0.15wt%;

[0049] S5: Turn on the UV lamp, adjust the lamp power to 800W, and the reaction begins;

[0050] S6: taking the above reaction water samples regularly during the reaction process to detect the COD concentration;

[0051] S7: After the above reaction is carried out for 10 min, the UV lamp is turned off to stop the reaction;

[0052] S8: Pour out the wastewater after the reaction, adjust the pH to 6.5-8, and let it stand for precipitation;

[0053] S9: Pour out the supernatant after standing, take a sample to test COD, wash the precipitate, filter and dry to obtain the original catalyst.

[0054] Comparative Example 2

[0055] For comparison, other treatment conditions are the same as those in Example 2, and the same wastewater is treated, except that the ferric chloride catalyst added in S4 is directly subjected to UV / H2O2 reaction, and in S8, the wastewater after the reaction is poured out and allowed to stand, and COD is sampled and tested, and the reaction is terminated. Figure 2 .

[0056] Example 3

[0057] This embodiment provides an efficient treatment method for wastewater containing dimethyl tetrachloride, which specifically includes:

[0058] S1: Determine the COD content of the dimethyl tetrachloride wastewater, and the measured COD=3500 mg / L;

[0059] S2: Take 5L of the dimethyl tetrachloride wastewater, adjust the pH to 5.0, and then add it into the reactor;

[0060] S3: Take 100 mL of hydrogen peroxide (wt=35%), i.e., the dosage is 2 wt% of the treated water, and add it to the above reactor, and stir it magnetically;

[0061] S4: Weigh a certain amount of catalyst Fe 2+ 0.45 Fe 3+ 0.075 Cu 2+ 0.475 , and then added to the above reaction solution after being completely dissolved, so that the catalyst Fe 2+ 0.45 Fe 3+ 0.075 Cu 2+ 0.475 The total mass concentration of metal ions in the wastewater is 0.2wt%;

[0062] S5: Turn on the UV lamp, adjust the lamp power to 750W, and the reaction begins;

[0063] S6: taking the above reaction water samples regularly during the reaction process to detect the COD concentration;

[0064] S7: After the above reaction is carried out for 10 min, the UV lamp is turned off to stop the reaction;

[0065] S8: Pour out the wastewater after the reaction, adjust the pH to 6.5-8, and let it stand for precipitation;

[0066] S9: Pour out the supernatant after standing, take a sample to test COD, wash the precipitate, filter and dry to obtain the original catalyst.

[0067] Comparative Example 3

[0068] For comparison, other treatment conditions are the same as those in Example 2, and the same wastewater is treated, except that: the copper hydroxide catalyst added in S4 is directly subjected to UV / H2O2 reaction, and in S8, the wastewater after the reaction is poured out and allowed to stand, and COD is sampled and tested, and the reaction is terminated. Figure 3 .

Claims

1. An advanced photocatalytic oxidation high-efficiency water treatment method for industrial wastewater treatment, characterized in that: The method is to determine the type of ultraviolet lamp, the amount of oxidant and the amount of catalyst according to the different water treatment amounts. The specific steps are as follows: S1: Determine the COD concentration of the industrial wastewater to be treated and adjust the pH value to 4-6; S2: Add oxidant and catalyst Fe to the industrial wastewater to be treated 2+ x Fe 3+ y Cu 2+ 1-x-y The dosage is determined according to the amount of water to be treated, Fe 2+ x Fe 3+ y Cu 2+ 1-x-y The x and y values ​​in are adjusted according to the response requirements; S3: Turn on the UV lamp to start the photocatalytic oxidation reaction.

2. The method according to claim 1, characterized in that The COD concentration in the industrial wastewater to be treated ranges from 1000 mg / L to 30000 mg / L.

3. The method according to claim 1, characterized in that The ultraviolet lamp is a medium pressure ultraviolet lamp.

4. The method according to claim 1 or 3, characterized in that: The power of a single UV lamp is 300~1000w, and the wavelength of ultraviolet light is 200~400nm.

5. The method according to claim 1, characterized in that The oxidant refers to one or more of persulfate, hydrogen peroxide, hypochlorite and the like.

6. The method according to claim 1 or 5, characterized in that: The dosage of the oxidant is 0.1-10 wt % of the treated water.

7. The method according to claim 1, characterized in that The catalyst Fe 2+ x Fe 3+ y Cu 2+ 1-x-y Contains Cu 2 + , Fe 2+ , Fe 3+ A solid catalyst, catalyst solution or catalyst dispersion containing one or more ions.

8. The method according to claim 1 or 7, characterized in that: Fe 2+ x Fe 3+ y Cu 2+ 1-x-y The x and y values ​​are adjusted according to the reaction requirements. In order to achieve reaction speed, x is controlled at 0~0.3 and y is controlled at 0~0.

1. In order to achieve high COD removal level, x is controlled at 0.3~0.8 and y is controlled at 0~0.

1. In order to achieve both accelerated reaction speed and improved COD removal level, x=0.45 and y=0.075 are controlled.

9. The method according to claim 1 or 8, characterized in that: The catalyst dosage is 0.01-1 wt% of the treated water.

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