A method for degrading organic pollutants by synergistic ultrasonic stirring of metal ions

Abstract

The present invention discloses a method for degrading organic pollutants by metal ion synergistic ultrasonic stirring, which comprises the following steps: S1. After adjusting the pH of the wastewater containing organic pollutants to 2.50 - 7.00, metal ions are added as catalysts, and the metal ions are one or more combinations of Fe<supgt;3+< / supgt>, Cu<supgt;2+< / supgt>, Al<supgt;3+< / supgt>, Ag<supgt;+< / supgt>, Ni<supgt;2+< / supgt>, Mg<supgt;2+< / supgt>, Ca<supgt;2+< / supgt>, Co<supgt;2+< / supgt>; S2. The wastewater obtained in S1 is placed in an ultrasonic device, and ultrasonic treatment is carried out while stirring is started under the condition that the ultrasonic temperature is 25 - 40 °C. After 40 - 100 min of ultrasonic stirring treatment, the degradation of organic pollutants in the wastewater is completed. The present invention has a degradation enhancement effect under the synergistic action of ultrasonic and mechanical stirring with metal ions, can strengthen the degradation technology, and can provide a reference for the field of industrial wastewater treatment.

Description

Technical Field

[0001] The present invention relates to the technical fields of sono-catalysis technology and environmental purification technology, and specifically refers to a method for degrading organic pollutants by metal ion synergistic ultrasonic stirring. Background Art

[0002] With the rapid development of the economy, the discharge of industrial wastewater is large, and the efficient treatment of refractory organic wastewater has always been a difficult problem in modern water treatment technology. At present, advanced oxidation technology has attracted extensive attention because it can remove organic pollutants in water, and hydroxyl radicals are in-situ generated through chemical methods, photochemical methods, and electrochemical methods to oxidize organic pollutants in water. Among them, ultrasonic catalysis technology is a kind of advanced oxidation technology, which has unique advantages such as simple equipment, easy operation, high efficiency, wide application range, no secondary pollution, and reusability. However, the energy loss of using ultrasonic technology alone is large and the degradation efficiency is low. In order to avoid the problems existing in the use of ultrasonic alone, combining ultrasonic with other technologies can effectively play the advantages of the two technologies and improve the degradation efficiency of organic pollutants. Therefore, combining other advanced oxidation technologies to develop a new type of ultrasonic catalysis combined technology with high degradation efficiency is a major difficulty in sono-catalysis technology.

[0003] In the use of combined technologies, the research results of Zhang et al. show that the degradation efficiency of organic pollutants is still affected by some operating parameters, such as: the type of reactor, the mechanical stirring speed, the initial concentration of organic pollutants, and the ultrasonic frequency (Ultrasonics Sonochemistry, 2019, 58, 104691). At present, there is no report on the method for degrading organic pollutants by metal ion synergistic ultrasonic stirring. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned background art, and provide a method for degrading organic pollutants by metal ion synergistic ultrasonic stirring. This method uses metal ions as catalysts to catalytically ultrasonically degrade rhodamine B solution under the action of stirring in an ultrasonic device. This technology is easy to operate and control, has a fast degradation rate, can be combined with other water treatment technologies, and can also treat organic pollutants with high toxicity and high degradation difficulty. Therefore, it has development potential and application prospects in the degradation of organic pollutants.

[0005] The technical solution of the present invention is as follows: A method for degrading organic pollutants by metal ion synergistic ultrasonic stirring, characterized by comprising the following steps:

[0006] S1. Adjust the pH of the wastewater containing organic pollutants to 2.50 - 7.00, and then add metal ions as catalysts. The metal ions are Fe 3+ , Cu 2+ , Al 3+ , Ag+ , Ni 2+ , Mg 2+ , Ca 2+ , Co 2+ or a combination of one or more thereof;

[0007] S2. Place the wastewater obtained in S1 in an ultrasonic device, and perform ultrasonic treatment while stirring at an ultrasonic temperature of 25 - 40°C. After 40 - 100 minutes of ultrasonic stirring treatment, the degradation of organic pollutants in the wastewater is completed.

[0008] Preferably, in step S2, the ultrasonic power is controlled to be 200 - 600 W, and the stirring speed is 400 - 1100 r / min.

[0009] Preferably, in step S1, the concentration of metal ions in the wastewater is 0.1 - 2.0 mmol / L.

[0010] Preferably, in step S1, the organic pollutants are one or a combination of more of rhodamine B, methylene blue, and methyl orange.

[0011] Preferably, in step S1, the concentration of organic pollutants in the wastewater is 2.00 - 10.00 mg / L.

[0012] Preferably, in step S1, the pH of the wastewater is adjusted by a sodium hydroxide solution with a concentration of 0.1 - 1 mol / L or nitric acid with a mass of 0.1 - 1 mol / L.

[0013] Preferably, in step S1, the Fe 3+ is obtained by adding Fe(NO 3 ) 3 ·9H 2 O or FeCl 3 ·6H 2 O into the wastewater. The Cu 2+ is obtained by adding Cu(NO 3 ) 2 ·3H 2 O or CuCl 2 ·2H 2 O into the wastewater. The Al 3+ is obtained by adding Al(NO 3 ) 3 ·9H 2 O into the wastewater. The Ag + is obtained by adding AgNO 3 into the wastewater. The Ni 2+ is obtained by adding Ni(NO 3 ) 2 ·6H 2 O into the wastewater. The Mg2+ It is obtained by adding Mg(NO 3 ) 2 ·6H 2 O into the wastewater. The Ca 2+ is obtained by adding Ca(NO 3 ) 2 ·4H 2 O into the wastewater. The Co 2+ is obtained by adding Co(NO 3 ) 2 ·6H 2 O into the wastewater.

[0014] Furthermore, in step S2, the ultrasonic power is controlled to be 320 - 400 W and the stirring speed is 800 - 1100 r / min.

[0015] Preferably, it includes the following steps:

[0016] S1. Adjust the pH of the wastewater containing organic pollutants to 2.50 - 4.10, and add metal ions as a catalyst. The organic pollutant is Rhodamine B and the concentration of Rhodamine B in the wastewater is 2.00 - 10.00 mg / L. The metal ion is Fe 3+ and the concentration of Fe 3+ in the wastewater is 0.5 mmol / L;

[0017] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment while stirring under the condition that the ultrasonic temperature is 25 - 40 °C, control the ultrasonic power to be 400 W and the stirring speed to be 800 r / min, and complete the degradation of the organic pollutant after 80 min of ultrasonic stirring treatment.

[0018] In the above scheme:

[0019] The role of adding metal ions is: The metal ions form a Fenton-like system with H 2 O 2 generated during ultrasonic treatment. The metal ions can react with H 2 O 2 generated by ultrasonic treatment, and can generate more hydroxyl radicals in a short time, increasing the concentration of hydroxyl radicals in the solution and promoting the degradation of organic pollutants.

[0020] The role of performing ultrasonic treatment is: The turbulent effect caused by ultrasonic treatment can increase the contact between hydroxyl radicals and organic pollutants by enhancing the sonochemical effect; Ultrasonic treatment accelerates the transformation of Fe 3+ to Fe 2+ ; The hydroxyl radicals generated by ultrasonic cavitation react chemically with the organic pollutants in the water, thereby achieving the degradation of organic substances.

[0021] The role of stirring is: in ultrasonic instruments, adding mechanical stirring will increase the uniformity of the sound field distribution and the sound pressure amplitude, and increase the cavitation area; under the same conditions, adding mechanical stirring will make the cavitation bubbles collapse more violently and increase the temperature inside the cavitation bubbles; introducing mechanical stirring can also promote the mass transfer effect of chemical reactions. All three effects can increase the cavitation intensity, thereby increasing the ultrasonic degradation rate of organic pollutants.

[0022] The principle of the synergistic effect of metal ions and ultrasonic stirring is: under the action of mechanical stirring, a large number of bubbles will be generated, and the stirring blades will shear the bubbles. In the solution, the bubbles generated by mechanical stirring can drive the sound field; at the same time, under the action of ultrasound, the formation, expansion and collapse of cavitation bubbles, the local high temperature and high pressure areas and drastic temperature changes generated provide energy for the generation of free radicals, and water molecules are prone to react to generate H 2 O 2 , ·OH and ·H. The shock wave generated by the bubble burst will cause the free radicals and hydrogen peroxide in the bubble to enter the solution. At the same time, metal ions are added, and the metal ions react with the H generated by ultrasound. 2 O 2 A Fenton-like system is formed, and a large number of hydroxyl radicals are generated in a short period of time. These oxidants can oxidize and degrade organic compounds in the solution. The cavitation effect and Fenton-like system produced by the synergistic effect of the three will accelerate the degradation of organic pollutants, significantly reduce the processing time and the number of catalysts or additives, increase the number of hydroxyl radicals in the reaction process, generate strong micro-turbulence to promote the effective utilization of hydroxyl radicals, and ultimately significantly improve the efficiency of degrading organic pollutants.

[0023] In the present invention, metal ion concentration, ultrasonic power and stirring rate are critical:

[0024] The metal ion concentration is 0.1-2.0 mmol / L, because too high a concentration will inhibit the H generated in the ultrasonic system. 2 O 2 The decomposition of hydroxyl radicals in the reaction system can reduce the degradation rate of organic pollutants. If the concentration is too low, a small amount of metal ions will not be able to continuously react with H 2 O 2 Reaction, it is impossible to produce a large amount of hydroxyl radicals in a short time.

[0025] The ultrasonic power is 200-600W. This is because too high a power will cause a large number of holes in a small volume, forming a hole cloud, reducing the efficiency of hole collapse, and too low a power will lead to a decrease in the number of cavitation bubbles and the number of hydroxyl radicals produced, thereby reducing the removal efficiency of organic pollutants.

[0026] The stirring speed is 400 - 1100 r / min. This is because if the speed is too high, cavitation bubbles will be sheared during the formation process, reducing the temperature inside the cavitation bubbles, thus affecting the cavitation effect and having an adverse impact on the degradation of organic substances. If the speed is too low, the sound field distribution in the ultrasonic instrument will be uneven and the range of the cavitation effect will decrease.

[0027] In step S1 of the present invention, the reason for controlling the initial pH of the wastewater to be 2.50 - 7.00 is as follows: Under acidic conditions, rhodamine B will exist in the form of molecules. Since both cavitation bubbles and rhodamine B molecules are hydrophobic, they approach each other. The hydroxyl radicals generated by cavitation bubbles during ultrasonic treatment will break the complex structure of rhodamine B, thereby degrading organic pollutants. In addition, when pH > 3, Fe 3+ begins to hydrolyze, and Fe(OH) 3 precipitate will be formed under alkaline conditions, thus reducing the concentration of Fe 3+ in the solution.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. Under ultrasonic and mechanical stirring, in synergistic action with metal ions, it has a degradation enhancement effect, can strengthen the degradation technology, and can provide a reference for the field of industrial wastewater treatment.

[0030] 2. The present invention uses the sono-catalysis technology, combines it with stirring to efficiently degrade organic pollutants, and has the characteristics of simple and efficient operation process, low cost, and reduced energy consumption, providing a broad prospect for the treatment of refractory organic wastewater by ultrasonic technology.

[0031] 3. The degradation rate of pollutants in the present invention is as high as 98.19%, and it can be used in combination with other water treatment technologies. It can also treat organic pollutants with high toxicity and high degradation resistance, so it has development potential and application prospects in the degradation of organic pollutants. Description of the Drawings

[0032] Figure 1 It is the rhodamine B degradation rate curve graph in Examples 1 - 3;

[0033] Figure 2 It is the rhodamine B degradation rate curve graph in Examples 1 and 4 - 10;

[0034] Figure 3 It is the rhodamine B degradation rate curve graph in Examples 1 and 11 - 15;

[0035] Figure 4 It is the rhodamine B degradation rate curve graph in Examples 1 and 16 - 17;

[0036] Figure 5It is the degradation rate curve graph of rhodamine B in Example 1 and Examples 18 - 19;

[0037] Figure 6 It is the degradation rate curve graph of rhodamine B in Example 1 and Examples 20 - 22;

[0038] Figure 7 It is the degradation rate curve graph of rhodamine B in Example 1 and Comparative Examples 1 - 2. Detailed implementation manners

[0039] The following specific examples further illustrate the present invention in detail. The drugs used in the examples are all commercially available products without special instructions, and the methods used are all conventional methods in the art. In the following examples: the ultrasonic device is an ultrasonic cleaning instrument with a fixed frequency of 40 kHz, adjustable power, and adjustable solution temperature inside the ultrasonic device; the wastewater is a rhodamine B solution prepared by the national standard method.

[0040] Example 1

[0041] The present invention provides a method for degrading organic pollutants by metal ion synergistic ultrasonic stirring, including the following steps:

[0042] S1. Add a sodium hydroxide solution with a concentration of 0.1 mol / L or nitric acid with a concentration of 0.1 mol / L to a 250 mL rhodamine B solution with a concentration of 5.0 mg / L to adjust the solution pH to 2.50, and add metal ion Fe 3+ as a catalyst. Fe 3+ is to add Fe(NO 3 ) 3 ·9H 2 O or FeCl 3 ·6H 2 O to obtain and the concentration of Fe 3+ in the rhodamine B solution is 0.5 mmol / L;

[0043] S2. Place the liquid obtained in S1 in the ultrasonic device, perform ultrasonic while turning on stirring under the condition that the ultrasonic temperature is 35 °C, the power of ultrasonic is 400 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 80 min to complete the degradation of the organic pollutants.

[0044] Measure the absorbance of the wastewater with a UV - visible spectrophotometer before ultrasonic stirring to obtain the original absorbance C 0 , during the ultrasonic stirring process, take the supernatant every 20 min and measure its absorbance with a UV - visible spectrophotometer, then the degradation rate = 100% - measured absorbance C / original absorbance C 0*100%, the degradation rates of Rhodamine B measured at ultrasonic stirring times of 20 min, 40 min, 60 min, and 80 min were 80.44%, 96.56%, 97.90%, and 98.19% respectively. It can be seen that the final degradation rate of Rhodamine B in this example is as high as 98.19%.

[0045] Example 2 - 3

[0046] The present invention provides a method for degrading organic pollutants by metal ion - assisted ultrasonic stirring, which includes the following steps:

[0047] S1. Add a sodium hydroxide solution with a concentration of 0.1 mol / L or nitric acid with a concentration of 0.1 mol / L to a 250 - mL Rhodamine B solution with a concentration of 5.0 mg / L to adjust the pH of the solution to 2.50. Add metal ion Fe 3+ As a catalyst, Fe 3+ is added to the solution by adding Fe(NO 3 ) 3 ·9H 2 O or FeCl 3 ·6H 2 O to obtain a solution with an Fe 3+ concentration of 0.5 mmol / L in the Rhodamine B solution;

[0048] S2. Place the liquid obtained in S1 in an ultrasonic device, and carry out ultrasonic treatment while starting stirring at an ultrasonic temperature of 35°C. The power of the ultrasonic wave is 400 W, and the stirring speeds are 400 r / min and 1100 r / min respectively. The ultrasonic stirring time is 80 min to complete the degradation of the organic pollutants.

[0049] Measure the degradation rate according to the degradation rate measurement method in Example 1. As Figure 1 shown, it is the influence of different stirring rates on the degradation rate of Rhodamine B. It can be Figure 1 seen that when the mechanical stirring speed is 800 r / min, the degradation effect is the best, and the degradation rate can reach 98.19%. The degradation rate data obtained from Examples 1 - 3 are shown in Table 1.

[0050] Table 1 Test parameters and degradation rates of Examples 1 - 3

[0051]

[0052] Examples 4 - 10

[0053] The present invention provides a method for degrading organic pollutants by metal ion - assisted ultrasonic stirring, which includes the following steps:

[0054] S1. Add sodium hydroxide solution with a concentration of 0.1 mol / L or nitric acid with a concentration of 0.1 mol / L to 250 mL of rhodamine B solution with a concentration of 5.0 mg / L to adjust the pH of the solution to 2.50, and then add metal ions Cu 2+ 、Co 2+ 、Ag + 、Ca 2+ 、Mg 2 + 、Al 3+ 、Ni 2+ as catalysts, and the concentration of each metal ion is 0.5 mmol / L (Cu 2+ is obtained by adding Cu(NO 3 ) 2 ·3H 2 O or CuCl 2 ·2H 2 O, Co 2+ is obtained by adding Co(NO 3 ) 2 ·6H 2 O, Ag + is obtained by adding AgNO 3 , Ca 2+ is obtained by adding Ca(NO 3 ) 2 ·4H 2 O, Mg 2+ is obtained by adding Mg(NO 3 ) 2 ·6H 2 O, Al 3+ is obtained by adding Al(NO 3 ) 3 ·9H 2 O, Ni 2+ is obtained by adding Ni(NO 3 ) 2 ·6H 2 O);

[0055] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment at an ultrasonic temperature of 35 °C while starting stirring, the power of ultrasonic treatment is 400 W, the stirring speed is 800 r / min in sequence, and the ultrasonic stirring time is 80 min to complete the degradation of organic pollutants.

[0056] Measure the degradation rate according to the degradation rate measurement method in Example 1. As Figure 2 shown, it is the influence of different kinds of metal ions on the degradation rate of rhodamine B. From Figure 2It can be seen that at the same metal ion concentration, the addition of metal ions has a promoting effect on the synergistic degradation of organic pollutants by ultrasonic stirring, among which Fe 3+ The effect on the synergistic degradation of organic pollutants by ultrasonic stirring is the greatest, and the degradation rate reaches 98.19%. The degradation rate data obtained in Example 1 and Examples 4-10 are shown in Table 2.

[0057] Table 2 Experimental parameters and degradation rates of Examples 1 and 4-10

[0058]

[0059] Examples 11-15

[0060] The present invention provides a method for degrading organic pollutants by using metal ions in coordination with ultrasonic stirring, comprising the following steps:

[0061] S1. Add 0.1 mol / L sodium hydroxide solution or 0.1 mol / L nitric acid to 250 mL of 5.0 mg / L rhodamine B solution, adjust the solution pH to 3.18, 4.07, 5.13, 5.92, and 6.96, respectively, and add metal ions Fe 3+ As a catalyst, Fe 3+ To add Fe(NO 3 ) 3 9H 2 O or FeCl 3 6H 2 O is obtained and Fe in Rhodamine B solution 3+ The concentration is 0.5mmol / L;

[0062] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonication at an ultrasonic temperature of 35°C while starting stirring, the ultrasonic power is 400W, the stirring speed is 800r / min, and the ultrasonic stirring time is 80min, thereby completing the degradation of organic pollutants.

[0063] Degradation rate was measured by the degradation rate determination method in Example 1. Figure 3 As shown in Figure 2, the effect of solution pH on the degradation rate of Rhodamine B is shown in Figure 2. Figure 3 It can be seen that when pH = 2.50, the degradation effect is the best, up to 98.19%. The degradation rate data obtained in Example 1 and Examples 11-15 are shown in Table 3.

[0064] Table 3 Test parameters and degradation rates of Example 1 and Examples 11-15

[0065]

[0066]

[0067] Examples 16 - 17

[0068] The present invention provides a method for degrading organic pollutants by metal ion synergistic ultrasonic stirring, comprising the following steps:

[0069] S1. Add a sodium hydroxide solution with a concentration of 0.1 mol / L or nitric acid with a concentration of 0.1 mol / L to a 250 mL rhodamine B solution with a concentration of 5.0 mg / L to adjust the pH of the solution to 2.50, and add metal ion Fe 3+ as a catalyst. Fe 3+ is added to the solution by adding Fe(NO 3 ) 3 ·9H 2 O or FeCl 3 ·6H 2 O to obtain a Fe 3+ concentration of 0.5 mmol / L in the rhodamine B solution;

[0070] S2. Place the liquid obtained in S1 in an ultrasonic device, and perform ultrasonic treatment while starting stirring at an ultrasonic temperature of 35°C. The power of the ultrasonic treatment is 400 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 80 min to complete the degradation of the organic pollutants.

[0071] Measure the degradation rate according to the degradation rate measurement method in Example 1. As Figure 4 shown, it is the influence of the initial concentration of rhodamine B on the degradation rate of rhodamine B. It can be seen from Figure 4 that when the concentration is 5.0 mg / L, the degradation effect is the best, up to 98.19%. The degradation rate data obtained in Example 1 and Examples 16 - 17 are shown in Table 4.

[0072] Table 4 Test parameters and degradation rates of Example 1 and Examples 16 - 17

[0073]

[0074] Examples 18 - 19

[0075] The present invention provides a method for degrading organic pollutants by metal ion synergistic ultrasonic stirring, comprising the following steps:

[0076] S1. Add a sodium hydroxide solution with a concentration of 0.1 mol / L or nitric acid with a concentration of 0.1 mol / L to a 250 mL rhodamine B solution with a concentration of 5.0 mg / L to adjust the pH of the solution to 2.50, and add metal ion Fe 3+ as a catalyst. Fe 3+ is added to the solution by adding Fe(NO 3 ) 3 ·9H2 O or FeCl 3 ·6H 2 O is obtained, and the concentration of Fe in the rhodamine B solution 3+ is 0.5 mmol / L;

[0077] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment at an ultrasonic temperature of 35 °C while starting stirring. The ultrasonic powers are 200 W and 320 W respectively, the stirring speed is 800 r / min, and the ultrasonic stirring time is 80 min to complete the degradation of organic pollutants.

[0078] Measure the degradation rate according to the degradation rate measurement method in Example 1. As Figure 5 shown, it is the influence of ultrasonic power on the degradation rate of rhodamine B. It can be seen from Figure 5 this that when the ultrasonic power is 400 W, the degradation effect is the best, up to 98.19%. The degradation rate data obtained in Example 1 and Examples 18 - 19 are shown in Table 5.

[0079] Table 5 Test parameters and degradation rates of Example 1 and Examples 18 - 19

[0080]

[0081] Examples 20 - 22

[0082] The present invention provides a method for degrading organic pollutants by metal ion - assisted ultrasonic stirring, which includes the following steps:

[0083] S1. Add a sodium hydroxide solution with a concentration of 0.1 mol / L or nitric acid with a concentration of 0.1 mol / L to a 250 - mL rhodamine B solution with a concentration of 5.0 mg / L to adjust the pH of the solution to 2.50. Add metal ion Fe 3+ as a catalyst. Fe 3+ is obtained by adding Fe(NO 3 ) 3 ·9H 2 O or FeCl 3 ·6H 2 O, and the concentration of Fe in the rhodamine B solution 3+ is 0.5 mmol / L;

[0084] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment at ultrasonic temperatures of 25 °C, 30 °C, and 40 °C respectively while starting stirring. The ultrasonic power is 400 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 80 min to complete the degradation of organic pollutants.

[0085] Measure the degradation rate according to the degradation rate measurement method in Example 1. AsFigure 6 As shown, it is the influence of ultrasonic temperature on the degradation rate of Rhodamine B. From Figure 6 it can be seen that when the ultrasonic temperature is 35 °C, the degradation effect is the best, up to 98.19%. The degradation rate data obtained in Example 1 and Examples 20 - 22 are shown in Table 6.

[0086] Table 6 Test parameters and degradation rate of Example 1 and Examples 20 - 22

[0087]

[0088] Comparative Example 1

[0089] This comparative example is a method for ultrasonic degradation of organic pollutants, including the following steps:

[0090] S1. Add sodium hydroxide solution with a concentration of 0.1 mol / L or nitric acid with a concentration of 0.1 mol / L to a 250 mL Rhodamine B solution with a concentration of 5.0 mg / L to adjust the pH of the solution to 2.50;

[0091] S2. Place the liquid obtained in S1 in an ultrasonic device, and perform ultrasonic treatment at an ultrasonic temperature of 35 °C. The power of the ultrasonic is 400 W and the time is 80 min to complete the degradation of the organic pollutants.

[0092] Comparative Example 2

[0093] This comparative example is a method for ultrasonic stirring degradation of organic pollutants, including the following steps:

[0094] S1. Add sodium hydroxide solution with a concentration of 0.1 mol / L or nitric acid with a concentration of 0.1 mol / L to a 250 mL Rhodamine B solution with a concentration of 5.0 mg / L to adjust the pH of the solution to 2.50;

[0095] S2. Place the liquid obtained in S1 in an ultrasonic device, and perform ultrasonic treatment while starting stirring at an ultrasonic temperature of 35 °C. The power of the ultrasonic is 400 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 80 min to complete the degradation of the organic pollutants.

[0096] The degradation rates of Comparative Example 1 and Comparative Example 2 were measured according to the degradation rate measurement method in Example 1. As Figure 7 shown, it is the degradation rate of Rhodamine B obtained in Comparative Examples 1 - 2 and Example 1. The degradation rate data obtained in Comparative Examples 1 - 2 and Example 1 are shown in Table 7.

[0097] Table 7 Test parameters and degradation rate of Comparative Examples 1 - 2 and Example 1

[0098]

[0099] FromFigure 7 It can be seen that the degradation rates of Rhodamine B in Comparative Example 1 at ultrasonic stirring times of 20 min, 40 min, 60 min, and 80 min are 3.12%, 1.99%, 5.77%, and 0% respectively, and the degradation rates of Rhodamine B in Comparative Example 2 at ultrasonic stirring times of 20 min, 40 min, 60 min, and 80 min are 40.37%, 60.70%, 71.36%, and 84.56% respectively. The degradation rates of Rhodamine B in Comparative Examples 1-2 at each moment are much lower than those in Example 1. Therefore, it can be shown that under ultrasonic and mechanical stirring, in cooperation with metal ions, there is a degradation enhancement effect.

Claims

1. A method for degrading organic pollutants by metal ion synergistic ultrasonic stirring, characterized in that, it comprises the following steps: S1. After adjusting the pH of the wastewater containing organic pollutants to 2.50 - 7.00, add metal ions as catalysts. The metal ions are Fe 3+ , Cu 2+ or a combination of one or two of them. The concentration of metal ions in the wastewater is 0.1 - 2.0 mmol / L, and the concentration of organic pollutants in the wastewater is 2.00 - 10.00 mg / L. The organic pollutants are one or a combination of two of Rhodamine B and Methylene Blue; S2. Place the wastewater obtained in S1 in an ultrasonic device, carry out ultrasonic treatment while starting stirring under the condition that the ultrasonic temperature is 25 - 40 °C, and after 40 - 100 min of ultrasonic stirring treatment, control the ultrasonic power to be 320 - 400 W and the stirring speed to be 800 r / min to complete the degradation of the organic pollutants in the wastewater.

2. The method for degrading organic pollutants by metal ion synergistic ultrasonic stirring according to claim 1, characterized in that, in step S1, the pH of the wastewater is adjusted by a sodium hydroxide solution with a concentration of 0.1 - 1 mol / L or nitric acid with a concentration of 0.1 - 1 mol / L.

3. The method for degrading organic pollutants by metal ion synergistic ultrasonic stirring according to claim 1, characterized in that, In step S1, the Fe 3+ is obtained by adding Fe(NO 3 ) 3 ·9H 2 O or FeCl 3 ·6H 2 O into the wastewater, and the Cu 2+ is obtained by adding Cu(NO 3 ) 2 ·3H 2 O or CuCl 2 ·2H 2 O into the wastewater.

4. The method for degrading organic pollutants by metal ion synergistic ultrasonic stirring according to claim 1, characterized in that, it comprises the following steps: S1. Adjust the pH of the wastewater containing organic pollutants to 2.50 - 4.10, and add metal ions as a catalyst. The organic pollutant is Rhodamine B and the concentration of Rhodamine B in the wastewater is 2.00 - 10.00 mg / L. The metal ion is Fe 3+ and the concentration of Fe 3+ in the wastewater is 0.5 mmol / L; S2. Place the liquid obtained in S1 in an ultrasonic device, carry out ultrasonic treatment while starting stirring under the condition that the ultrasonic temperature is 25 - 40 °C, control the ultrasonic power to be 400 W and the stirring speed to be 800 r / min, and after 80 min of ultrasonic stirring treatment, complete the degradation of the organic pollutants.

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