Method for degrading organic pollutants in water

Abstract

The invention belongs to the field of environmental protection, and particularly relates to a method for degrading organic pollutants in water, which comprises the following steps: injecting compressed gas into sewage to form gas-dissolved water, and simultaneously performing electron beam irradiation on the sewage to degrade the organic pollutants in the sewage. According to the invention, the electric field of the micro-nano bubbles is stronger than that in water, so that the micro-nano bubbles are easy to discharge at the junction of the bubbles and the liquid level. On the basis, a gas-liquid interface is created in an electron beam irradiation technology, so that gas and water molecules at the gas-liquid interface are subjected to efficient electron release at the same time under the action of electron beam irradiation, a series of element reactions are generated, and various active substances including strong oxidizing free radicals, H2O2 and the like are generated; therefore, efficient oxidative degradation of organic pollutants in the sewage is realized; in addition, the dissolved gas can also greatly increase the contact area of free radicals and active ions generated by excitation of organic molecules and electrons in a liquid phase, so that the degradation efficiency of the organic pollutants is further improved.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection, and particularly relates to a method for degrading organic pollutants in water. Background Art

[0002] Currently, the application of nuclear technology in the field of environmental protection has become increasingly diversified and mature. In water treatment, nuclear technology is widely used in sewage treatment, purification, disinfection, and removal of characteristic pollutants. The electron beam irradiation water treatment technology mainly uses high-energy electron beams to irradiate sewage, and a series of chemical and biological effects are generated through ionization, excitation and other reactions, so that organic substances are decomposed or converted into harmless substances. In this process, water molecules in the sewage will decompose to generate strong oxidizing substances (such as hydroxyl radicals, ozone, etc.) under the irradiation of high-energy electron beams, and these substances act on the organic pollutants in the sewage to achieve oxidative decomposition.

[0003] At present, the application of electron beam irradiation in water treatment has not been fully exerted, and the removal effect of pollutants is not good. Therefore, it is imperative to develop a new electron beam irradiation process. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for degrading organic pollutants in water, which creates a gas-liquid interface in the electron beam irradiation technology, reduces the mass transfer resistance, and realizes the efficient degradation of organic pollutants in water.

[0005] The present invention provides a method for degrading organic pollutants in water, including the following steps:

[0006] Inject compressed gas into the sewage to form dissolved gas water, and at the same time irradiate the sewage with an electron beam to achieve the degradation of organic pollutants in the sewage.

[0007] Preferably, the degradation method specifically includes the following steps: injecting sewage and compressed gas into an electron beam reaction device to form dissolved gas water, and at the same time performing electron beam irradiation to achieve the degradation of organic pollutants in the sewage.

[0008] Preferably, the compressed gas is air, oxygen or ozone.

[0009] Preferably, the ratio of the volume flow rate of the sewage to the volume flow rate of the injected compressed gas is 1:(2-4).

[0010] Preferably, the bubble diameter in the dissolved gas water is 50-150 nm.

[0011] Preferably, the electron beam is generated by an electron accelerator.

[0012] Preferably, the power of the electron accelerator is 60-120 kW, and the beam current intensity is 30-60 mA.

[0013] Preferably, the time of the electron beam irradiation is 0.05 to 0.3 s.

[0014] Preferably, the thickness of the water layer during the electron beam irradiation of the sewage is 1 to 5 mm.

[0015] Preferably, the COD of the sewage is 300 to 600 mg / L.

[0016] Compared with the prior art, the present invention provides a method for degrading organic pollutants in water, comprising the following steps: injecting compressed gas into the sewage to form dissolved gas water, and simultaneously irradiating the sewage with an electron beam to achieve the degradation of organic pollutants in the sewage. The present invention discovers that the electric field of micro-nano bubbles is stronger than that in water, and discharge is prone to occur at the junction of the bubble and the liquid surface. Based on this, the present invention creates a gas-liquid interface in the electron beam irradiation technology, enabling the gas and water molecules at the gas-liquid interface to simultaneously undergo efficient electron release under the action of the electron beam irradiation and generate a series of elementary reactions, producing various active substances, including strongly oxidizing free radicals (such as ·OH, ·H, ·O, ·HO2, etc.), H2O2, etc., thereby achieving the efficient oxidative degradation of organic pollutants in the sewage; moreover, the dissolved gas can greatly increase the contact area between the organic molecules in the liquid phase and the free radicals and active ions generated by electron excitation, thereby further enhancing the degradation efficiency of organic pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0018] Figure 1 It is a process flow chart provided by an embodiment of the present invention.

[0019] Description of the reference numerals: 1 is a gas compressor, 2 is an electron accelerator, and 3 is an electron beam reaction device under the beam. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following clearly and completely describes the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] The present invention provides a method for degrading organic pollutants in water, comprising the following steps:

[0022] Compressed gas is injected into the sewage to form dissolved gas water, and at the same time, the sewage is irradiated with an electron beam to achieve the degradation of organic pollutants in the sewage.

[0023] In the degradation method provided by the present invention, it more specifically includes the following steps: sewage and compressed gas are injected into an electron beam reaction device to form dissolved gas water, and at the same time, electron beam irradiation is carried out to achieve the degradation of organic pollutants in the sewage.

[0024] In the degradation method provided by the present invention, the COD of the sewage is preferably 300 - 600 mg / L, and specifically can be 300 mg / L, 350 mg / L, 400 mg / L, 450 mg / L, 500 mg / L, 550 mg / L or 600 mg / L.

[0025] In the degradation method provided by the present invention, the compressed gas is preferably air, oxygen or ozone. Among them, when the compressed gas is air or oxygen, after O2 gains electrons, it usually first generates oxygen anions ·O 2- , on the one hand, the oxygen anions can promote the growth and activity of microorganisms in water, thereby accelerating the biodegradation rate and improving the efficiency of sewage treatment; on the other hand, the gas-liquid interface mass transfer effect decomposes water molecules into free radicals such as ·OH, ·H, ·O, ·HO2, etc., and the free radicals combine with the pollutants in the water and are converted into harmless or low-toxic substances through chemical reactions, thereby removing the pollutants. When the compressed gas is ozone, on the one hand, ozone itself has strong oxidizing properties and can remove pollutants, and on the other hand, mass transfer occurs at the gas-liquid interface under the action of electrons, water molecules are decomposed, and free radicals such as ·OH, ·H, ·O, ·HO2, etc. are generated, and the pollutants are removed after the free radicals react with organic substances or small molecule substances.

[0026] In the degradation method provided by the present invention, the ratio of the volume flow rate of the sewage to the volume flow rate of the injected compressed gas is preferably 1:(2 - 4), and specifically can be 1:2, 1:2.5, 1:3, 1:3.5 or 1:4.

[0027] In the degradation method provided by the present invention, the bubble diameter in the dissolved gas water is preferably 50 - 150 nm, and specifically can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm or 150 nm.

[0028] In the degradation method provided by the present invention, the electron beam is generated by an electron accelerator; the power of the electron accelerator is preferably 60-120 kW, specifically 60 kW, 70 kW, 80 kW, 90 kW, 100 kW, 110 kW or 120 kW; the beam current intensity of the electron accelerator is preferably 30-60 mA, specifically 30 mA, 35 mA, 40 mA, 45 mA, 50 mA, 55 mA or 60 mA.

[0029] In the degradation method provided by the present invention, the irradiation time of the electron beam is preferably 0.05-0.3 s, specifically 0.05 s, 0.1 s, 0.15 s, 0.2 s, 0.25 s or 0.3 s.

[0030] In the degradation method provided by the present invention, the water layer thickness during the electron beam irradiation of the sewage is preferably 1-5 mm, specifically 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm.

[0031] In the degradation method provided by the present invention, the specific process of realizing the degradation of organic pollutants includes: the bubbles in the dissolved air water break under the action of electron beam irradiation and generate a variety of active substances that can oxidize and degrade organic substances, and the active substances oxidize and degrade the organic pollutants in the sewage.

[0032] The technical solution provided by the present invention creates a gas-liquid interface in the electron beam irradiation technology, reduces the mass transfer resistance, realizes the efficient degradation of organic pollutants in sewage, and has good application prospects.

[0033] For the sake of clarity, the following is a detailed description through the following examples.

[0034] Example 1

[0035] A method for degrading pollutants by a dissolved air type electron beam is as Figure 1 shown, and the specific process is as follows:

[0036] Inject the influent and the compressed gas generated by the compressor 1 into the electron beam reactor 3 below the electron beam to form dissolved air water. At the same time, irradiate the electron beam reactor 3 below the electron beam with an electron beam through the electron accelerator 2 above the electron beam reactor 3; the bubbles in the dissolved air water break under the action of electron beam irradiation and generate a variety of active substances that can oxidize and degrade organic substances, and the active substances oxidize and degrade the organic pollutants in the water to obtain the treated effluent;

[0037] Among them, the influent COD is 450 mg / L, and the influent volume flow rate is 100 m 3 / h, the compressed gas is compressed air, the ratio of the inlet gas volume flow rate of the compressed air to the inlet water volume flow rate is 2:1, the bubble diameter in the dissolved air water is about 100 nm, the power of the electron accelerator 2 is 80 kW, the beam current intensity is 40 mA, the water layer thickness in the electron beam downward reaction device 3 is 2 mm, and the cumulative irradiation time of the inlet water is 0.2 s.

[0038] Control group experiment: Referring to the above experimental process, the only difference is that no compressed gas is injected into the electron beam downward reaction device 3.

[0039] The experimental results are shown in Table 1:

[0040] Table 1 Experimental results of sewage in Example 1

[0041] Scheme COD (mg / L) COD Removal Rate / % Raw Water 450 / Control Group (Electron Beam Irradiation) 325 27.8 Experimental Group (Dissolved Air Electron Beam Irradiation) 210 53.3

[0042] Example 2

[0043] A method for degrading pollutants by a dissolved air electron beam, as Figure 1 shown, the specific process is as follows:

[0044] Inject the inlet water and the compressed gas generated by the compressor 1 into the electron beam downward reaction device 3 to form dissolved air water. At the same time, irradiate the electron beam downward reaction device 3 with an electron beam through the electron accelerator 2 above the electron beam downward reaction device 3; the bubbles in the dissolved air water rupture under the action of the electron beam irradiation and generate various active substances that can oxidize and degrade organic substances, and the active substances oxidize and degrade the organic pollutants in the water to obtain the treated effluent;

[0045] Among them, the inlet water COD is 500 mg / L, the inlet water volume flow rate is 150 m 3 / h, the compressed gas is compressed air, the ratio of the inlet gas volume flow rate of the compressed air to the inlet water volume flow rate is 3:1, the bubble diameter in the dissolved air water is about 100 nm, the power of the electron accelerator 2 is 100 kW, the beam current intensity is 50 mA, the water layer thickness in the electron beam downward reaction device 3 is 2 mm, and the cumulative irradiation time of the inlet water is 0.2 s.

[0046] Control group experiment: Referring to the above experimental process, the only difference is that no compressed gas is injected into the electron beam downward reaction device 3.

[0047] The experimental results are shown in Table 2:

[0048] Table 2 Experimental results of sewage in Example 2

[0049] Scheme COD (mg / L) COD Removal Rate / % Raw Water 500 / Control Group (Electron Beam Irradiation) 350 30.0 Experimental Group (Dissolved Air Electron Beam Irradiation) 200 60.0

[0050] Example 3

[0051] A method for degrading pollutants by dissolved air electron beam is as follows: Figure 1 As shown below, the specific process is as follows:

[0052] Inject the influent water and the compressed gas generated by the compressor 1 into the electron beam reaction device 3 under the electron beam to form dissolved air water. At the same time, irradiate the electron beam reaction device 3 with an electron beam through the electron accelerator 2 above the electron beam reaction device 3. The bubbles in the dissolved air water rupture under the action of electron beam irradiation and generate various active substances that can oxidize and degrade organic substances. The active substances oxidize and degrade the organic pollutants in the water to obtain the treated effluent water;

[0053] Among them, the influent COD is 500 mg / L, the influent volume flow rate is 150 m 3 / h, the compressed gas is compressed ozone, the ratio of the inlet volume flow rate of the compressed ozone to the influent volume flow rate is 3:1, the bubble diameter in the dissolved air water is about 100 nm, the power of the electron accelerator 2 is 100 kW, the beam current intensity is 50 mA, the water layer thickness in the electron beam reaction device 3 is 2 mm, and the cumulative irradiation time of the influent water is 0.2 s.

[0054] Control group experiment: Referring to the above experimental process, the difference is only that no compressed gas is injected into the electron beam reaction device 3.

[0055] The experimental results are shown in Table 3:

[0056] Table 3 Experimental results of the sewage in Example 3

[0057] Scheme COD (mg / L) COD Removal Rate / % Raw Water 500 / Control Group (Electron Beam Irradiation) 350 30.0 Experimental Group (Dissolved Air Electron Beam Irradiation) 175 65.0

[0058] The above is only the preferred implementation mode of the present invention. It should be pointed out that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A method for degrading organic pollutants in water, characterized in that, Including the following steps: Inject compressed gas into the sewage to form dissolved air water, and at the same time irradiate the sewage with electron beam to achieve the degradation of organic pollutants in the sewage.

2. The degradation method according to claim 1, wherein Specifically including the following steps: Inject the sewage and compressed gas into the reaction device under the electron beam to form dissolved air water. At the same time, conduct electron beam irradiation to achieve the degradation of organic pollutants in the sewage.

3. The degradation method according to claim 1, wherein The compressed gas is air, oxygen or ozone.

4. The degradation method according to claim 1, characterized in that, The ratio of the volume flow rate of the sewage to the volume flow rate of the injected compressed gas is 1:(2 - 4).

5. The degradation method according to claim 1, wherein The bubble diameter in the dissolved air water is 50 - 150 nm.

6. The degradation method according to claim 1, wherein The electron beam is generated by an electron accelerator.

7. The degradation method according to claim 6, wherein The power of the electron accelerator is 60 - 120 kW, and the beam current intensity is 30 - 60 mA.

8. The degradation method according to claim 1, characterized in that The time of electron beam irradiation is 0.05 - 0.3 s.

9. The degradation method according to claim 1, wherein When the sewage is irradiated with electron beam, the water layer thickness is 1 - 5 mm.

10. The degradation method according to any one of claims 1 to 9, characterized in that, The COD of the sewage is 300 - 600 mg / L.

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