A method for degrading organic pollutants by synergistic action of persulfate, ultrasonic wave and stirring

Abstract

The present invention discloses a method for degrading organic pollutants by synergistic action of persulfate, ultrasound and stirring, which includes: S1, adjusting the pH of the wastewater containing organic pollutants to 3.00 - 10.60 and then adding persulfate, or adjusting the pH of the wastewater containing organic pollutants to 3.00 - 7.70 and then adding persulfate and metal ions, where the metal ions are one or more 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, placing the wastewater obtained in S1 in an ultrasonic device, performing ultrasound and simultaneously starting stirring under the condition that the ultrasonic temperature is 25 - 55 °C, and completing the degradation of the organic pollutants in the wastewater after 5 - 120 min of ultrasonic stirring treatment. The present invention has a significant enhancement effect on the degradation efficiency under the action of ultrasound and mechanical stirring, in synergistic action with persulfate, can strengthen the degradation technology, and can provide a reference for the field of industrial wastewater treatment.

Description

Technical Field

[0001] The invention relates to the field of sonic catalysis technology and environmental purification technology, and in particular to a method for degrading organic pollutants with persulfate or persulfate combined with metal ions in coordinated ultrasonic stirring. Background Art

[0002] At present, the discharge of industrial wastewater is large, and the refractory organic matter in water bodies has caused great harm to the environment. However, traditional wastewater treatment methods are difficult to efficiently treat refractory organic wastewater, which is a difficult problem that needs to be solved urgently in the field of modern water treatment. Advanced oxidation technology is an oxidation process based on strong oxidizing free radicals. It can decompose refractory organic matter into small molecules. Because of its mild reaction conditions and fast reaction rate, it has become a research hotspot. Among them, the sulfate free radical (SO4 ·- ) is developing rapidly, and its source is mainly persulfate, which is considered to be a suitable substitute for hydrogen peroxide because of its advantages such as higher stability, stronger oxidizing property, higher organic matter oxidation selectivity, wider pH adaptability, mild reaction conditions and easy activation. Persulfate can be activated by ultraviolet light, heat, ultrasound, alkali, activated carbon, quinones, phenols, soil minerals, radiation dissolution and transition metals. Among them, the instantaneous local high temperature and high pressure generated by ultrasonic cavitation in ultrasonic catalysis technology can activate persulfate to produce SO4 ·- , and ultrasound has the characteristics of being unaffected by water quality, not generating secondary pollution and low energy consumption, but using ultrasound technology alone has the disadvantages of large energy loss, long reaction time and low degradation efficiency, so ultrasound and other oxidation technologies are usually used together. The synergistic effect can effectively exert the advantages of the two technologies, reduce process costs and improve the degradation efficiency of organic pollutants. Therefore, ultrasound technology combined with other oxidation technologies is a technology with great application prospects. Developing a new type of ultrasound-catalysis combined technology with high degradation efficiency is a major difficulty of sonocatalysis technology.

[0003] Currently, there is no report on the method of degrading organic pollutants by using persulfate or persulfate combined with metal ions in coordination with ultrasonic stirring. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the above-mentioned background technology and provide a method for degrading organic pollutants by using persulfate or a mixture of persulfate and metal ions in coordination with ultrasonic stirring. The method uses persulfate or a mixture of persulfate and metal ions as a catalyst, and catalytically ultrasonically degrades a rhodamine B solution in an ultrasonic device under the action of mechanical stirring. The technology has high degradation efficiency and can also treat a variety of difficult-to-degrade organic pollutants, so 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 persulfate or persulfate combined with metal ions synergistically under ultrasonic stirring, which is characterized by including the following steps:

[0006] S1. Perform the first treatment or the second treatment on the wastewater containing organic pollutants.

[0007] The first treatment is to adjust the pH of the wastewater to 3.00 - 10.60 and then add persulfate.

[0008] The second treatment is to adjust the pH of the wastewater to 3.00 - 7.70 and then add persulfate and metal ions. The metal ions are one or more combinations of Fe 3+ , Cu 2+ , Al 3+ , Ag + , Ni 2+ , Mg 2+ , Ca 2+ , Co 2+ ;

[0009] S2. Place the wastewater obtained in S1 in an ultrasonic device, and perform ultrasonic treatment while starting stirring under the condition that the ultrasonic temperature is 25 - 55 °C. After 5 - 120 min of ultrasonic stirring treatment, the degradation of organic pollutants in the wastewater is completed.

[0010] Preferably, in step S2, the ultrasonic power is controlled to be 80 - 800 W and the stirring speed is 200 - 1100 r / min.

[0011] Preferably, in step S1, the concentration of persulfate in the wastewater in the first treatment and the second treatment is 0.04 - 0.36 g / L.

[0012] Preferably, in step S1, the concentration of metal ions in the wastewater in the second treatment is 0.1 - 3.0 mmol / L.

[0013] Preferably, in step S1, the organic pollutants are one or more combinations of cationic dyes, anionic dyes and antibiotics.

[0014] Further, the cationic dye is one or two combinations of rhodamine B and methyl orange, the anionic dye is one or two combinations of acid red G and congo red, and the antibiotic is tetracycline hydrochloride.

[0015] Preferably, in step S1, the concentration of organic pollutants in the wastewater is 5.00 - 50.00 mg / L.

[0016] Preferably, in step S1, the pH of the wastewater is adjusted by a sodium hydroxide solution with a concentration of 0.1 - 1.0 mol / L or nitric acid with a mass of 0.1 - 1.0 mol / L.

[0017] Preferably, in step S1, the persulfate is one or a combination of potassium peroxymonosulfate PMS, potassium persulfate K2S2O8, sodium persulfate Na2S2O8, or ammonium persulfate (NH4)2S2O8.

[0018] In step S1, during the second treatment, the Fe 3+ is obtained by adding Fe(NO3)3·9H2O or FeCl3·6H2O to the wastewater, and the Cu 2+ is obtained by adding Cu(NO3)2·3H2O or CuCl2·2H2O to the wastewater, and the Al 3+ is obtained by adding Al(NO3)3·9H2O to the wastewater, and the Ag + is obtained by adding AgNO3 to the wastewater, and the Ni 2+ is obtained by adding Ni(NO3)2·6H2O to the wastewater, and the Mg 2+ is obtained by adding Mg(NO3)2·6H2O to the wastewater, and the Ca 2+ is obtained by adding Ca(NO3)2·4H2O to the wastewater, and the Co 2+ is obtained by adding Co(NO3)2·6H2O to the wastewater.

[0019] Preferably, it includes the following steps:

[0020] S1. Perform the first treatment or the second treatment on the wastewater containing organic pollutants.

[0021] The first treatment is to adjust the pH of the wastewater to 3.00 - 10.60 and then add persulfate.

[0022] The second treatment is to adjust the pH of the wastewater to 3.00 - 7.70 and then add persulfate and metal ions. The organic pollutant is rhodamine B and the concentration of rhodamine B in the wastewater is 5.00 - 50.00 mg / L. The persulfate in both the first treatment and the second treatment is potassium peroxymonosulfate, and the concentration of persulfate in the wastewater is 0.24 g / L.

[0023] 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 - 55 °C, control the ultrasonic power to be 240 W and the stirring speed to be 800 r / min, and complete the degradation of the organic pollutant after 20 - 50 min of ultrasonic stirring treatment.

[0024] In the above scheme:

[0025] The functions of adding persulfate are as follows: Under ultrasonic irradiation, persulfate will generate sulfate radicals and hydroxyl radicals, increasing the types of radicals in the system; the addition of persulfate will produce the synergistic effect of H2O2 and persulfate; sulfate radicals react with water to generate hydroxyl radicals, increasing the number of hydroxyl radicals in the system, thereby improving the efficiency of the system in oxidizing organic pollutants.

[0026] The functions of adding metal ions are as follows: Metal ions and H2O2 generated by ultrasound form a Fenton-like system; it improves the efficiency of ultrasound-activated persulfate in continuously generating sulfate radicals and hydroxyl radicals, thereby improving the oxidation performance of the system and ultimately greatly increasing the removal rate of organic pollutants.

[0027] The functions of ultrasonic treatment are as follows: The turbulent effect caused by ultrasound can increase the contact between reactive radicals and organic pollutants by enhancing the sonochemical effect; ultrasound can accelerate the activation of persulfate to generate sulfate radicals, with faster kinetics; ultrasonic cavitation can continuously accelerate the chemical reaction between hydroxyl radicals and organic pollutants in water, thereby achieving the degradation of organic matter.

[0028] The functions of stirring are as follows: In an ultrasonic instrument, adding mechanical stirring will increase the uniformity of the sound field distribution and the sound pressure amplitude, improving the cavitation area; under the same conditions, adding mechanical stirring will cause the cavitation bubbles to collapse more violently, increasing the temperature inside the cavitation bubbles; introducing mechanical stirring can also increase the degree of turbulence brought by ultrasound, enabling persulfate, metal ions, and organic pollutants to come into full contact. All three functions can improve the ultrasonic cavitation intensity, thereby increasing the ultrasonic degradation rate of organic pollutants.

[0029] The principle of the synergistic effect of the mixture of persulfate, metal ions, and ultrasonic stirring is as follows: Under the action of mechanical stirring, a large number of bubbles will be generated, and the generated bubbles can drive the sound field; at the same time, under the action of ultrasound, the formation, expansion, and collapse of cavitation bubbles produce local high-temperature and high-pressure regions and drastic temperature changes, providing energy for the generation of radicals. Water molecules are prone to react to generate H2O2, ·OH, and ·H. The mechanical stirring intensifies the bubble rupture, causing the radicals and hydrogen peroxide in the bubbles to enter the solution; at the same time, persulfate and metal ions are added. Metal ions and H2O2 generated by ultrasound form a Fenton-like system. In a short time, metal ions and ultrasound simultaneously activate persulfate to generate a large amount of sulfate radicals and hydroxyl radicals. The strongly oxidizing reactive radicals can oxidize and degrade organic compounds in the solution. The cavitation effect, persulfate activation system, and Fenton-like system generated by the synergistic effect of the four will accelerate the degradation of organic pollutants, significantly reducing the treatment time and the dosage of additives. The number of hydroxyl radicals during the reaction process increases, generating strong microscopic turbulence to promote the effective utilization of strongly oxidizing reactive radicals, and ultimately significantly improving the efficiency of degrading organic pollutants.

[0030] In the present invention, the metal ion concentration, persulfate concentration, ultrasonic power, and stirring rate are crucial:

[0031] The persulfate concentration is 0.04 - 0.36 g / L. When the persulfate increases from 0.04 g / L to 0.24 g / L, the removal rate of organic pollutants increases sharply because the higher the persulfate concentration, the more strong oxidative free radicals are generated; when the persulfate increases from 0.24 g / L to 0.36 g / L, the removal rate of organic pollutants decreases slightly because when the persulfate concentration is too high, sulfate radicals will react with each other and be consumed.

[0032] The metal ion concentration is 0.1 - 3.0 mmol / L. This is because if the metal ion concentration is too small, a small amount of metal ions cannot continuously react with H2O2, cannot continuously activate persulfate, and cannot generate a large amount of active free radicals in a short time; if the metal ion concentration is too large, it will inhibit the decomposition of H2O2 generated in the ultrasonic system. Excessive metal ions have a competitive effect with active free radicals, reducing the number of hydroxyl free radicals in the reaction system, thereby reducing the degradation rate of organic pollutants;

[0033] The ultrasonic power is 80 - 800 W. When ultrasound acts on the solution, cavitation and microflows will form in the solution, and both will generate turbulence, enhancing mass transfer in the solution; the increase in ultrasonic power can accelerate the activation of persulfate to generate free radicals and also accelerate the generation of free radicals. Therefore, an increase in ultrasonic power within an appropriate range has a positive effect on the degradation of organic pollutants. However, a larger ultrasonic power will generate a cavitation cloud that will terminate the propagation of sound in the liquid, reducing the efficiency of cavitation collapse and weakening the cavitation effect.

[0034] The stirring speed is 200 - 1100 r / min. This is because if the mechanical stirring speed is too small, the sound field distribution in the ultrasonic instrument will be uneven and the range of the cavitation effect will be reduced; if the speed is too large, the cavitation bubbles will be sheared during the formation process, prematurely destroying the high-temperature and high-pressure environment inside the cavitation bubbles, thereby affecting the cavitation effect and resulting in an unfavorable consequence of low degradation rate of organic matter.

[0035] In step S1 of the present invention, in the system of persulfate combined with metal ions and ultrasonic stirring, the reason for controlling the initial pH of the wastewater to be 3.00 - 7.70 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, and the hydroxyl free radicals generated by cavitation bubbles during ultrasound 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, thereby reducing Fe in the solution 3+Concentration. In the system of persulfate combined with ultrasonic stirring, the reason for controlling the initial pH of the wastewater to be 3.00 - 10.60 is that the dominant species of PMS is HSO5 when pH < 9.4 - , which can be activated into sulfate radicals under ultrasonic conditions; while when pH > 9.4, the dominant species in the system is SO5 2- , reducing the generation of active radicals in the system; in addition, the pH range of the system is not limited by metal ions, so the initial pH range of the wastewater is relatively large.

[0036] The beneficial effects of the present invention are as follows:

[0037] 1. Under ultrasonic and mechanical stirring, in synergistic action with persulfate or a mixture of persulfate and 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.

[0038] 2. The present invention uses sono-catalysis technology, combines it with mechanical stirring and oxidation technology 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.

[0039] 3. The pollutant degradation rate of the present invention is as high as 99.53%, and it can be used in combination with other water treatment technologies, and can also treat organic pollutants with high toxicity and high refractoriness, so it has development potential and application prospects in the degradation of organic pollutants. Description of the Drawings

[0040] Figure 1 It is the rhodamine B degradation rate curve graph in Examples 1 - 3;

[0041] Figure 2 It is the rhodamine B degradation rate curve graph in Examples 1 and 10 - 11;

[0042] Figure 3 It is the rhodamine B degradation rate curve graph in Examples 12 - 15;

[0043] Figure 4 It is the rhodamine B degradation rate curve graph in Examples 14 and 16 - 17;

[0044] Figure 5 It is the rhodamine B degradation rate curve graph in Examples 14 and 24 - 26;

[0045] Figure 6 It is the rhodamine B degradation rate curve graph in Examples 14 and 27 - 33;

[0046] Figure 7 It is the rhodamine B degradation rate curve graph in Examples 14 and 34 - 35;

[0047] Figure 8 Curves of degradation rates in Example 1 and Examples 36 - 39

[0048] Figure 9 Curves of degradation rates of Rhodamine B in Example 1 and Examples 40 - 41

[0049] Figure 10 Curves of degradation rates of Rhodamine B in Example 1, Example 14 and Comparative Examples 1 - 3 Detailed implementation manners

[0050] 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 without special instructions. In the following examples: The ultrasonic device is an ultrasonic cleaning instrument with a fixed frequency of 40 kHz, adjustable power, and the temperature of the solution in the ultrasonic device can be adjusted by circulating water.

[0051] Examples 1 - 3

[0052] The present invention provides a method for degrading organic pollutants by persulfate synergistic ultrasonic stirring, comprising the following steps:

[0053] 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, adjust the pH to 5.85, add PMS as an oxidant, and the concentrations of PMS in the Rhodamine B solution are 0.24 g / L, 0.04 g / L, and 0.36 g / L respectively;

[0054] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment while turning on stirring at an ultrasonic temperature of 35°C, the power of ultrasonic treatment is 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 50 min to complete the degradation of organic pollutants.

[0055] Before ultrasonic stirring, measure the absorbance of the wastewater with a UV - visible spectrophotometer to obtain the original absorbance C0. During ultrasonic stirring, take the supernatant every 5 min and measure its absorbance with a UV - visible spectrophotometer. Then the degradation rate = 100% - measured absorbance C / original absorbance C0 * 100%. As Figure 1 shown, it is the influence of different concentrations of PMS on the degradation rate of Rhodamine B. From Figure 1It can be seen that when the concentration of PMS in the rhodamine B solution is 0.24 g / L, the degradation effect is the best. The degradation rates of rhodamine B measured at ultrasonic stirring times of 10 min, 20 min, 30 min, 40 min, and 50 min are 51.17%, 73.68%, 87.04%, 94.15%, and 97.76% respectively. The degradation rate data obtained in Examples 1-3 are shown in Table 1.

[0056] Table 1 Test parameters and degradation rates of Examples 1-3

[0057]

[0058] Examples 4-5

[0059] The present invention provides a method for degrading organic pollutants by persulfate synergistic ultrasonic stirring, comprising the following steps:

[0060] 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, adjust the pH to 5.85, add PMS as an oxidant, and the concentration of PMS is 0.24 g / L;

[0061] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic waves while turning on stirring under the condition that the ultrasonic temperature is 35 °C. The ultrasonic powers are 160 W and 800 W respectively, the stirring speed is 800 r / min, and the ultrasonic stirring time is 50 min to complete the degradation of the organic pollutants.

[0062] According to the degradation rate measurement method in Examples 1-3, the degradation rate is measured. The degradation rate data obtained in Example 1 and Examples 4-5 are shown in Table 2, which shows the influence of different ultrasonic powers on the degradation rate of rhodamine B. When the ultrasonic power is 240 W, the degradation effect is better, and the degradation rate can reach 97.76%.

[0063] Table 2 Test parameters and degradation rates of Example 1 and Examples 4-5

[0064]

[0065] Examples 6-7

[0066] The present invention provides a method for degrading organic pollutants by persulfate synergistic ultrasonic stirring, comprising the following steps:

[0067] 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, adjust the pH to 5.85, add PMS as an oxidant, and the concentration of PMS is 0.24 g / L;

[0068] S2. Place the liquid obtained in S1 into an ultrasonic device, perform ultrasonic treatment while turning on stirring at an ultrasonic temperature of 35 °C. The power of the ultrasonic treatment is 240 W, the stirring speeds are 400 r / min and 1100 r / min respectively, and the ultrasonic stirring time is 50 min to complete the degradation of organic pollutants.

[0069] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. The degradation rate data obtained in Example 1 and Examples 6 - 7 are shown in Table 3, which shows the influence of different mechanical stirring speeds on the degradation rate of Rhodamine B. When the mechanical stirring speed is 800 r / min, the degradation effect is better and the degradation rate can reach 97.76%.

[0070] Table 3 Test parameters and degradation rates of Example 1 and Examples 6 - 7

[0071]

[0072] Examples 8 - 9

[0073] The present invention provides a method for degrading organic pollutants by persulfate synergistic ultrasonic stirring, which includes the following steps:

[0074] 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, adjust the pH to 5.85, and add PMS as an oxidant. The concentration of PMS is 0.24 g / L;

[0075] S2. Place the liquid obtained in S1 into an ultrasonic device, perform ultrasonic treatment while turning on stirring at ultrasonic temperatures of 25 °C and 55 °C respectively. The power of the ultrasonic treatment is 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 50 min to complete the degradation of organic pollutants.

[0076] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. The degradation rate data obtained in Example 1 and Examples 8 - 9 are shown in Table 4, which shows the influence of different ultrasonic powers on the degradation rate of Rhodamine B. Under the condition of an ultrasonic temperature of 35 °C, the degradation effect is the best and the degradation rate can reach 97.76%.

[0077] Table 4 Test parameters and degradation rates of Example 1 and Examples 8 - 9

[0078]

[0079] Examples 10 - 11

[0080] The present invention provides a method for degrading organic pollutants by persulfate synergistic ultrasonic stirring, which includes the following steps:

[0081] 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, adjust the pH to 3.09 and 10.52 respectively, add PMS as an oxidant, and the concentration of PMS is 0.24 g / L;

[0082] 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 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 50 min to complete the degradation of organic pollutants.

[0083] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3, as Figure 2 shown, it is the influence of different wastewater pH values on the degradation rate of rhodamine B. It can be seen from Figure 2 that when the wastewater pH = 5.85, the degradation effect is better, and the degradation rate can reach 97.76%. The degradation rate data obtained in Example 1 and Examples 10 - 11 are shown in Table 5.

[0084] Table 5 Test parameters and degradation rates of Example 1 and Examples 10 - 11

[0085]

[0086] Examples 12 - 15

[0087] The present invention provides a method for degrading organic pollutants by combining persulfate with metal ions and synergistic ultrasonic stirring, which includes the following steps:

[0088] 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, adjust the pH to 5.85, add PMS and Fe 3+ as an oxidant, Fe 3+ is obtained by adding Fe(NO3)3·9H2O or FeCl3·6H2O to the solution, and the Fe 3+ concentrations in the rhodamine B solution are 0.1 mmol / L, 1.0 mmol / L, 2.0 mmol / L, 3.0 mmol / L respectively, and the concentration of PMS is 0.24 g / L;

[0089] 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 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring times are 20 min, 20 min, 20 min, 10 min respectively to complete the degradation of organic pollutants.

[0090] Determine the degradation rate according to the degradation rate determination method in Examples 1-3. As Figure 3 shown, from Figure 3 it can be seen that when the concentration of Fe 3+ is 2.0 mmol / L, the degradation effect is better, and the degradation rate at 20 min is 94.67%. The degradation rate data obtained in Examples 12-15 are shown in Table 6.

[0091] Table 6 Test parameters and degradation rates of Examples 12-15

[0092]

[0093] Examples 16-17

[0094] The present invention provides a method for degrading organic pollutants by combining persulfate with metal ions and synergistically ultrasonic stirring, comprising the following steps:

[0095] 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, adjust the pH to 5.85, add PMS and Fe 3+ as an oxidant. Fe 3+ is obtained by adding Fe(NO3)3·9H2O or FeCl3·6H2O to the solution, and the concentration of Fe 3+ in the rhodamine B solution is 2.0 mmol / L, and the PMS concentrations are 0.04 g / L and 0.36 g / L respectively;

[0096] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment while starting stirring under the condition that the ultrasonic temperature is 35°C, the power of ultrasonic treatment is 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 20 min to complete the degradation of the organic pollutants.

[0097] Determine the degradation rate according to the degradation rate determination method in Examples 1-3. As Figure 4 shown, it is the influence of different concentrations of PMS on the degradation rate of rhodamine B. From Figure 4 it can be seen that when the concentration of PMS is 0.24 g / L, the degradation effect is better, and the degradation rate at 20 min can reach 94.67%. The degradation rate data obtained in Examples 14 and 16-17 are shown in Table 7.

[0098] Table 7 Test parameters and degradation rates of Examples 14 and 16-17

[0099]

[0100] Examples 18-19

[0101] The present invention provides a method for degrading organic pollutants by combining persulfate with metal ions and synergistically ultrasonic stirring, comprising the following steps:

[0102] 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, adjust the pH to 5.85, and add PMS and Fe 3+ As an oxidant, Fe 3+ is obtained by adding Fe(NO3)3·9H2O or FeCl3·6H2O to the solution, and the Fe 3+ concentration in the rhodamine B solution is 2.0 mmol / L, and the PMS concentration is 0.24 g / L;

[0103] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment while stirring is turned on at an ultrasonic temperature of 35 °C. The ultrasonic powers are 80 W and 800 W respectively, the stirring speed is 800 r / min, and the ultrasonic stirring times are 50 min and 20 min respectively, to complete the degradation of the organic pollutants.

[0104] The degradation rates were measured according to the degradation rate measurement method in Examples 1 - 3. The degradation rate data obtained in Examples 14 and 18 - 19 are shown in Table 8. When the ultrasonic power is 240 W, the degradation effect is better, and the degradation rate at 20 min can reach 94.67%.

[0105] Table 8 Test parameters and degradation rates of Examples 14 and 18 - 19

[0106]

[0107] Examples 20 - 21

[0108] The present invention provides a method for degrading organic pollutants by combining persulfate with metal ions and synergistically ultrasonic stirring, comprising the following steps:

[0109] 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, adjust the pH to 5.85, and add PMS and Fe 3+ As an oxidant, Fe 3+ is obtained by adding Fe(NO3)3·9H2O or FeCl3·6H2O to the solution, and the Fe 3+ concentration in the rhodamine B solution is 2.0 mmol / L, and the PMS concentration is 0.24 g / L;

[0110] 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 240 W, the stirring speeds are 200 r / min and 1100 r / min respectively, and the ultrasonic stirring time is 20 min to complete the degradation of organic pollutants.

[0111] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. The degradation rate data obtained in Examples 14 and 20 - 21 are shown in Table 9, which shows the influence of different mechanical stirring speeds on the degradation rate of Rhodamine B. When the stirring speed is 800 r / min, the degradation effect is better, and the degradation rate at 20 min can reach 94.67%.

[0112] Table 9 Test parameters and degradation rates of Examples 14 and Examples 20 - 21

[0113]

[0114] Examples 22 - 23

[0115] The present invention provides a method for degrading organic pollutants by the synergistic ultrasonic stirring of persulfate combined with metal ions, which includes the following steps:

[0116] 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, adjust the pH to 5.85, add PMS and Fe 3+ As an oxidant, Fe 3+ is obtained by adding Fe(NO3)3·9H2O or FeCl3·6H2O to the solution, and the concentration of Fe in the Rhodamine B solution 3+ is 2.0 mmol / L, and the concentration of PMS is 0.24 g / L;

[0117] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment at ultrasonic temperatures of 25 °C and 55 °C respectively while starting stirring. The power of ultrasonic treatment is 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 20 min to complete the degradation of organic pollutants.

[0118] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. The degradation rate data obtained in Examples 14 and Examples 22 - 23 are shown in Table 10, which shows the influence of different ultrasonic temperatures on the degradation rate of Rhodamine B. When the ultrasonic temperature is 35 °C, the degradation effect is better, and the degradation rate at 20 min can reach 94.67%.

[0119] Table 10 Test parameters and degradation rates of Examples 14 and Examples 22 - 23

[0120]

[0121] Examples 24 - 26

[0122] The present invention provides a method for degrading organic pollutants by the synergistic action of persulfate combined with metal ions and ultrasonic stirring, comprising the following steps:

[0123] 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, adjust the pH to 3.09, 4.76, and 7.64 respectively, and add PMS and Fe 3+ As an oxidant, Fe 3+ is obtained by adding Fe(NO3)3·9H2O or FeCl3·6H2O to the solution, and the concentration of Fe in the rhodamine B solution 3+ is 2.0 mmol / L, and the concentration of PMS is 0.24 g / L;

[0124] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment while starting stirring at an ultrasonic temperature of 35°C, the power of ultrasonic is 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 20 min to complete the degradation of the organic pollutants.

[0125] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. As Figure 5 shown, it is the influence of different wastewater pH values on the degradation rate of rhodamine B. It can be seen from Figure 5 this that when the pH is 3.09, the degradation effect is better, and the degradation rate at 20 min can reach 98.99%. The degradation rate data obtained in Example 14 and Examples 24 - 26 are shown in Table 11.

[0126] Table 11 Test parameters and degradation rates of Example 14 and Examples 24 - 26

[0127]

[0128] Examples 27 - 33

[0129] The present invention provides a method for degrading organic pollutants by the synergistic action of persulfate combined with metal ions and ultrasonic stirring, comprising the following steps:

[0130] 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, adjust the pH to 5.85, and add metal ions Cu 2+ , Co 2+ , Ag + , Ca 2+, Mg 2+ , Al 3+ , Ni 2+ As catalysts, the metal ion concentrations are all 2.0 mmol / L (Cu 2+ is obtained by adding Cu(NO3)2·3H2O or CuCl2·2H2O to the solution, Co 2+ is obtained by adding Co(NO3)2·6H2O to the solution, Ag + is obtained by adding AgNO3 to the solution, Ca 2+ is obtained by adding Ca(NO3)2·4H2O to the solution, Mg 2+ is obtained by adding Mg(NO3)2·6H2O to the solution, Al 3+ is obtained by adding Al(NO3)3·9H2O to the solution, Ni 2+ is obtained by adding Ni(NO3)2·6H2O to the solution), and the concentration of PMS added is 0.24 g / L;

[0131] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment at an ultrasonic temperature of 35 °C while turning on stirring. The power of ultrasonic treatment is 240 W, the stirring speeds are successively 800 r / min, and the ultrasonic stirring times are 30 min, 5 min, 30 min, 30 min, 30 min, 20 min, and 10 min respectively to complete the degradation of organic pollutants.

[0132] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. As Figure 6 shown, it is the influence of different kinds of metal ions on the degradation rate of Rhodamine B. It can be Figure 6 seen that at the same PMS concentration, the addition of PMS all has a promoting effect on the ultrasonic stirring synergistic degradation of organic pollutants. Among them, Co 2+ has the greatest influence on the ultrasonic stirring synergistic degradation of organic pollutants, and the degradation rate of Rhodamine B at 5 min reaches 99.53%. The degradation rate data obtained in Example 14 and Examples 27 - 33 are shown in Table 12.

[0133] Table 12 Test parameters and degradation rates of Example 14 and Examples 27 - 33

[0134]

[0135] Examples 34 - 35

[0136] The present invention provides a method for degrading organic pollutants by the synergistic ultrasonic stirring of persulfate combined with metal ions, including the following steps:

[0137] 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 50.0 mg / L, adjust the pH to 5.85, and add PMS or a mixture of PMS and Fe 3+ The mixture, the concentration of PMS is 0.24 g / L, and Fe 3+ is obtained by adding Fe(NO3)3·9H2O or FeCl3·6H2O to the solution, and the concentration of Fe 3+ in the rhodamine B solution is 2.0 mmol / L;

[0138] S2. Place the liquid obtained in S1 in an ultrasonic device, carry out ultrasonic treatment at an ultrasonic temperature of 35 °C while starting stirring, the power of ultrasonic treatment is 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring times are 60 min and 120 min respectively to complete the degradation of organic pollutants.

[0139] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. As Figure 7 shown, it is the degradation rate of PMS or a mixture of PMS and Fe 3+ synergistically ultrasonic stirring to degrade rhodamine B with different concentrations. It can be Figure 7 seen that under the condition of PMS synergistically ultrasonic stirring, for 50.0 mg / L RhB, the degradation rate reaches 92.61% at 120 min; under the condition of a mixture of PMS and Fe 3+ synergistically ultrasonic stirring, for 5.0 mg / L RhB, the degradation rate reaches 94.67% at 20 min, and for 50.0 mg / L RhB, the degradation rate reaches 90.33% at 60 min.

[0140] The degradation rate data obtained in Example 14 and Examples 34 - 35 are shown in Table 13.

[0141] Table 13 Test parameters and degradation rates of Example 14 and Examples 34 - 35

[0142]

[0143] Examples 36 - 39

[0144] The present invention provides a method for degrading organic pollutants by synergistically ultrasonic stirring persulfate combined with metal ions, including the following steps:

[0145] S1. Respectively 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 methyl orange, acid red G, congo red, and tetracycline hydrochloride solutions with a concentration of 5.0 mg / L, adjust the pH to 5.85, and add PMS, and the concentration of PMS is 0.24 g / L;

[0146] S2. Place the liquid obtained in S1 into an ultrasonic device, perform ultrasonic treatment while turning on stirring at an ultrasonic temperature of 35 °C. The power of ultrasonic treatment is 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring times are 40 min, 40 min, 40 min, and 50 min respectively to complete the degradation of organic pollutants.

[0147] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. As Figure 8 shown, it is the degradation rate of different pollutants degraded by PMS combined with ultrasonic stirring. It can be Figure 8 seen that the effects of PMS combined with ultrasonic stirring in degrading methyl orange (MO), acid red G (ARG), congo red (CR), and tetracycline hydrochloride (TC) are all very good. The degradation rate data obtained in Example 1 and Examples 36 - 39 are shown in Table 14.

[0148] Table 14 Test parameters and degradation rates of Example 1 and Examples 36 - 39

[0149]

[0150] Examples 40 - 41

[0151] The present invention provides a method for degrading organic pollutants by persulfate combined with metal ions and ultrasonic stirring, comprising the following steps:

[0152] 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 respectively, adjust the pH to 5.85, and add sodium persulfate and ammonium persulfate respectively. The concentration of persulfate is 0.24 g / L;

[0153] S2. Place the liquid obtained in S1 into an ultrasonic device, perform ultrasonic treatment while turning on stirring at an ultrasonic temperature of 35 °C. The power of ultrasonic treatment is 240 W, the stirring speed is 800 r / min, and the ultrasonic stirring time is 30 min to complete the degradation of organic pollutants.

[0154] Measure the degradation rate according to the degradation rate measurement method in Examples 1 - 3. As Figure 9 shown, it is the influence of different persulfates on the degradation rate of rhodamine B. It can be Figure 9 seen that the effect of sodium persulfate combined with ultrasonic stirring in degrading rhodamine B is the best, and the degradation rate of rhodamine B in 30 min is as high as 92.40%. The degradation rate data obtained in Example 1 and Examples 40 - 41 are shown in Table 15.

[0155] Table 15 Test parameters and degradation rates of Example 1 and Examples 40 - 41

[0156]

[0157]

[0158] Comparative Example 1

[0159] This comparative example is a method for ultrasonic degradation of organic pollutants, including the following steps:

[0160] 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, adjust the pH to 5.85, and add PMS with a concentration of 0.24 g / L;

[0161] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment at an ultrasonic temperature of 35°C, with an ultrasonic power of 240 W and a time of 20 min to complete the degradation of organic pollutants.

[0162] Comparative Example 2

[0163] This comparative example is a method for ultrasonic stirring degradation of organic pollutants, including the following steps:

[0164] 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, adjust the pH to 5.85;

[0165] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment at an ultrasonic temperature of 35°C while starting stirring, with an ultrasonic power of 240 W, a stirring speed of 800 r / min, and an ultrasonic stirring time of 20 min to complete the degradation of organic pollutants.

[0166] Comparative Example 3

[0167] This comparative example is a method for ultrasonic stirring degradation of organic pollutants, including the following steps:

[0168] 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, adjust the pH to 5.85, and add Fe 3+ with a concentration of 2.0 mmol / L;

[0169] S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment at an ultrasonic temperature of 35°C while starting stirring, with an ultrasonic power of 240 W, a stirring speed of 800 r / min, and an ultrasonic stirring time of 20 min to complete the degradation of organic pollutants.

[0170] The degradation rates of Comparative Examples 1-3 were measured according to the degradation rate measurement method in Examples 1-3. As Figure 10 shown, the degradation rates of Rhodamine B obtained from Comparative Examples 1-3 and Examples 1 and 14 are presented. The 20-minute degradation rate data obtained from Comparative Examples 1-3 and Examples 1 and 14, as well as the degradation rates at ultrasonic stirring times of 5 min, 10 min, 15 min, and 20 min, are shown in Tables 16-17:

[0171] Table 16 Test parameters and degradation rates of Comparative Examples 1-3 and Examples 1 and 14

[0172]

[0173] Table 17 Degradation rates at various times of Comparative Examples 1-3 and Examples 1 and 14

[0174]

[0175] From Figure 10 Table 18, it can be seen that the degradation rates of Rhodamine B in Comparative Examples 1-3 at each moment are much lower than those in Examples 1 and 14. Therefore, it can be demonstrated that under ultrasonic and mechanical stirring, there is a synergistic effect and a degradation enhancement effect with the mixture of persulfate and metal ions.

Claims

1. A method for degrading organic pollutants by synergistic action of persulfate, ultrasonic wave and stirring, characterized in that, It includes the following steps: S1. Perform a second treatment on the wastewater containing organic pollutants. The second treatment is to adjust the pH of the wastewater to 3.00 - 7.70 and then add persulfate and metal ions. The metal ion is Al 3+ , the concentration of metal ions in the wastewater is 0.1 - 3.0 mmol / L, the concentration of persulfate is 0.04 - 0.36 g / L, the concentration of organic pollutants in the wastewater is 5.00 - 50.00 mg / L, the organic pollutants are one or more combinations of cationic dyes, anionic dyes and antibiotics, the persulfate is one or more combinations of potassium peroxymonosulfate, potassium persulfate, sodium persulfate, ammonium persulfate, and 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; S2. Place the wastewater obtained in S1 in an ultrasonic device, perform ultrasonic treatment while stirring under the condition that the ultrasonic temperature is 25 - 55 °C, and after 5 - 120 min of ultrasonic stirring treatment, control the ultrasonic power to be 240 - 800 W and the stirring speed to be 800 - 1100 r / min to complete the degradation of organic pollutants in the wastewater.

2. The method for degrading organic pollutants by persulfate synergistic ultrasonic stirring according to claim 1, characterized in that In step S1, during the second treatment, the Al 3+ is obtained by adding Al(NO3)3·9H2O to the wastewater.

3. The method for degrading organic pollutants by persulfate synergistic ultrasonic stirring according to claim 1, wherein It includes the following steps: S1. Perform a second treatment on the wastewater containing organic pollutants. The second treatment is to adjust the pH of the wastewater to 3.00 - 7.70 and then add persulfate and metal ions. The organic pollutant is rhodamine B and the concentration of rhodamine B in the wastewater is 5.00 - 50.00 mg / L. When performing the second treatment, the persulfate is potassium monopersulfate and the concentration of persulfate in the wastewater is 0.24 g / L; S2. Place the liquid obtained in S1 in an ultrasonic device, perform ultrasonic treatment while stirring under the condition that the ultrasonic temperature is 35 °C, control the ultrasonic power to be 240 W and the stirring speed to be 800 r / min, and after 20 - 50 min of ultrasonic stirring treatment, complete the degradation of organic pollutants.

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