Method for degrading organic pollutants

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a method for degrading organic pollutants. The method for degrading the organic pollutants disclosed by the embodiment of the invention comprises the following steps: carrying out electron beam irradiation on sewage containing the organic pollutants, and carrying out aeration treatment at the bottom of the sewage, and the gas adopted by the aeration treatment is air. According to the method, the electron beam irradiation technology and the bottom aeration treatment are combined, high-molecular organic pollutants can be efficiently degraded, so that the organic pollutants are thoroughly degraded to reach the emission standard, and the method has the advantages of low cost, good economy, no newly-added dangerous waste and salinity risk and the like, and is very suitable for sewage treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a method for degrading organic pollutants. Background Art

[0002] Organic sewage refers to sewage mainly composed of organic pollutants. Organic sewage can easily cause eutrophication of water quality and is quite harmful. Organic sewage has the following characteristics: 1. High concentration of organic matter: COD is usually greater than 2000 mg / L, or even as high as tens of thousands or even hundreds of thousands of mg / L, while BOD value is low. The ratio of BOD to COD of many wastewaters is less than 0.3; 2. Complex composition; may contain sulfides, heavy metals, nitrides, aromatic compounds, heterocyclic compounds and other toxic organic matter; 3. High chroma, odor, and stench, causing great trouble to the environment and surrounding residents; 4. Usually has strong acidity and strong alkalinity; 5. It is difficult to directly treat organic pollutants in sewage by biodegradation.

[0003] It has become an important demand in the industry to deeply treat difficult-to-degrade organic wastewater to meet environmental emission standards. Traditional organic wastewater treatment processes include pretreatment, biochemical treatment, adsorption, advanced oxidation, membrane separation and other deep treatment technologies. However, these traditional processes have significant technical bottlenecks: it is difficult to degrade most long-chain organic pollutants; it is necessary to build multi-stage treatment units, resulting in lengthy treatment processes, high costs, complex operations, and poor stability; it is necessary to add a large amount of chemical agents, and a large amount of hazardous waste sludge is generated during the treatment process, increasing the cost of hazardous waste treatment and the risk of environmental hazards; the large amount of dissolved oxidants used increases the salinity and other toxic and harmful components in the wastewater, making it difficult to meet environmental emission standards.

[0004] Therefore, it is crucial to research and develop organic wastewater treatment processes that can efficiently degrade organic pollutants and have good economic efficiency. Summary of the invention

[0005] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0006] In recent years, electron beam irradiation for wastewater treatment has been gradually promoted in the industry. This technology does not produce or discharge toxic byproducts during wastewater treatment, and does not have adverse effects on the environment and lives of surrounding residents, making it highly competitive in the market. However, the use of electron beam irradiation alone to treat wastewater still has problems such as difficulty in effectively degrading high-molecular organic wastewater, low efficiency, and high cost. Therefore, it is of great significance to study a method that can efficiently treat high-molecular compounds.

[0007] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, an embodiment of the present invention provides a method for degrading organic pollutants, which can efficiently degrade high molecular organic compounds, has low treatment costs, good economic efficiency, and has no new hazardous waste and salinity risks, and is very suitable for application in sewage treatment.

[0008] The method for degrading organic pollutants in the embodiment of the present invention comprises: irradiating sewage containing organic pollutants with electron beams, and performing aeration treatment at the bottom of the sewage, wherein the gas used in the aeration treatment is air.

[0009] The advantages and technical effects brought by the method for degrading organic pollutants in the embodiment of the present invention are as follows: 1. The method in the embodiment of the present invention combines electron beam irradiation technology with aeration treatment technology, and can efficiently degrade high-molecular organic pollutants, especially high-concentration, difficult-to-degrade and long-chain high-molecular organic pollutants. It has a good degradation effect and enhances the treatment efficiency of organic pollutants, thereby completely reducing organic pollutants to emission standards; 2. The method in the embodiment of the present invention has the advantages of low treatment cost, good economy and no new hazardous waste and salinity risks, and is very suitable for application in the field of sewage treatment.

[0010] In some embodiments, a catalyst is added during the electron beam irradiation process.

[0011] In some embodiments, the catalyst is a multi-metal oxygen-containing material; wherein the metal includes at least one of magnesium, calcium, titanium, vanadium, chromium, manganese, molybdenum, tungsten, iron, cobalt, nickel and copper.

[0012] In some embodiments, the amount of the catalyst added is 0.05 to 10 kg / m 3 .

[0013] In some embodiments, the irradiation dose of the electron beam is 0.5-30 kGy.

[0014] In some embodiments, the electron beam irradiation is performed in the form of pulse irradiation or continuous irradiation.

[0015] In some embodiments, the air contains nitrous oxide.

[0016] In some embodiments, the volume fraction of nitrous oxide is 0.05-30%.

[0017] In some embodiments, the intensity of the aeration treatment is 0.1 to 10 Nm 3 / (m 2 h). DETAILED DESCRIPTION

[0018] Embodiments of the present invention are described in detail below. The embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0019] The method for degrading organic pollutants in the embodiment of the present invention comprises: irradiating sewage containing organic pollutants with electron beams, and performing aeration treatment at the bottom of the sewage, wherein the gas used in the aeration treatment is air.

[0020] The method for degrading organic pollutants in the embodiment of the present invention combines electron beam irradiation technology with aeration treatment technology, and can efficiently degrade high-molecular organic pollutants, especially has a good degradation effect on high-concentration, difficult-to-degrade and long-chain high-molecular organic pollutants, thereby enhancing the treatment efficiency of organic pollutants, thereby completely reducing organic pollutants to emission standards; it has the advantages of low treatment cost, good economy and no new hazardous waste and salinity risks, and is very suitable for application in the field of sewage treatment.

[0021] In some embodiments, preferably, a catalyst is added during the electron beam irradiation process. Further preferably, the catalyst is a multi-metal oxygen-containing material, wherein the metal includes at least one of magnesium, calcium, titanium, vanadium, chromium, manganese, molybdenum, tungsten, iron, cobalt, nickel and copper.

[0022] In the embodiment of the present invention, adding a catalyst during the electron beam irradiation process can further improve the degradation rate of organic pollutants, thereby effectively improving the treatment speed of organic wastewater.

[0023] In some embodiments, preferably, the amount of the catalyst added is 0.05 to 10 kg / m 3 .

[0024] In the embodiments of the present invention, the amount of catalyst added is optimized to ensure that the cost of sewage treatment is reduced on the basis of having a good treatment effect, thereby having better economy.

[0025] In some embodiments, preferably, the irradiation dose of the electron beam is 0.5 to 30 kGy.

[0026] In some embodiments, preferably, the energy of the electron beam irradiation is 1-10 MeV, and the beam current intensity is 20-300 mA. Further preferably, the energy of the electron beam irradiation is 2-3 MeV, and the beam current intensity is 100-200 mA.

[0027] In some embodiments, preferably, the electron beam irradiation is performed by pulse irradiation or continuous irradiation. Further preferably, when pulse irradiation is performed, the single irradiation time is 0.01 to 2 seconds, the interval is 1 to 120 seconds, and the number of pulses is 1 to 3 times; when continuous irradiation is performed, the irradiation time is 0.01 to 6 seconds.

[0028] In some embodiments, preferably, the air contains nitrous oxide. Further preferably, the volume fraction of the nitrous oxide is 0.05 to 30%. More preferably, the volume fraction of the nitrous oxide is 10 to 30%.

[0029] In the embodiment of the present invention, air containing nitrous oxide is used during the aeration treatment process. Since nitrous oxide and oxygen in the air can synergistically promote the generation of oxidative free radicals during electron beam irradiation, the concentration of oxidative free radicals in sewage is increased, thereby having a positive effect on the oxidative degradation of organic pollutants and improving the overall treatment effect. If the content of nitrous oxide is too low or too high, local nitrous oxide or oxygen will be depleted, affecting the progress of the chemical reaction, which is not conducive to improving the treatment effect of organic pollutants in sewage.

[0030] In some embodiments, preferably, the intensity of the aeration treatment is 0.1 to 10 Nm 3 / (m 2 h); wherein N represents standard conditions, that is, the air condition is a standard atmospheric pressure, a temperature of 0°C, and a relative humidity of 0%.

[0031] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0032] Example 1

[0033] (1) Pour 1L of the liquid to be treated into a container of 1dm×1dm×1.5dm, put 100mg of a multi-metal oxygen-containing material catalyst into it, and then perform electron beam irradiation treatment; wherein the multi-metal oxygen-containing material catalyst is multi-metal oxide particles containing iron, nickel, and copper, which are loaded on a porous carbon matrix; the electron beam irradiation energy is 2MeV, the beam current intensity is 150mA; the electron beam irradiation mode is pulse irradiation, the single irradiation time is 0.5s, the interval is 5s, and the number of pulses is 3 times; the electron beam irradiation dose is 10kGy;

[0034] (2) Aeration treatment is performed at the bottom of the container. The aeration gas is air containing nitrous oxide, where the volume fraction of nitrous oxide is 15% and the intensity of the aeration treatment is 5 Nm 3 / (m 2 h).

[0035] Example 2

[0036] (1) Pour 1L of the liquid to be treated into a container of 1dm×1dm×1.5dm, put 100mg of a multi-metal oxygen-containing material catalyst into it, and then perform electron beam irradiation treatment; wherein the multi-metal oxygen-containing material catalyst is multi-metal oxide particles containing iron, nickel, and copper, which are loaded on a porous carbon matrix; the electron beam irradiation energy is 2MeV, the beam current intensity is 150mA; the electron beam irradiation mode is pulse irradiation, the single irradiation time is 0.5s, the interval is 30s, and the number of pulses is 3 times; the electron beam irradiation dose is 10kGy;

[0037] (2) Aeration is performed at the bottom of the container. The aeration gas is air and the intensity of the aeration is 5 Nm 3 / (m 2 h).

[0038] Example 3

[0039] (1) Pour 1L of the liquid to be treated into a container of 1dm×1dm×1.5dm, put 100mg of a multi-metal oxygen-containing material catalyst into it, and then perform electron beam irradiation treatment; wherein the multi-metal oxygen-containing material catalyst is multi-metal oxide particles containing iron, nickel, and copper, which are loaded on a porous carbon matrix; the electron beam irradiation energy is 2MeV, the beam current intensity is 50mA; the electron beam irradiation mode is pulse irradiation, the single irradiation time is 0.5s, the interval is 5s, and the number of pulses is 3 times; the electron beam irradiation dose is 7kGy;

[0040] (2) Aeration treatment is performed at the bottom of the container. The aeration gas is air containing nitrous oxide, where the volume fraction of nitrous oxide is 15% and the intensity of the aeration treatment is 5 Nm 3 / (m 2 h).

[0041] Example 4

[0042] (1) Pour 1L of the liquid to be treated into a container of 1dm×1dm×1.5dm, put 100mg of a multi-metal oxygen-containing material catalyst into it, and then perform electron beam irradiation treatment; wherein the multi-metal oxygen-containing material catalyst is multi-metal oxide particles containing iron, nickel, and copper, which are loaded on a porous carbon matrix; the electron beam irradiation energy is 2MeV, the beam current intensity is 150mA; the electron beam irradiation mode is pulse irradiation, the single irradiation time is 0.01s, the interval is 120s, and the number of pulses is 3 times; the electron beam irradiation dose is 10kGy;

[0043] (2) Aeration treatment is performed at the bottom of the container. The aeration gas is air containing nitrous oxide, where the volume fraction of nitrous oxide is 5% and the intensity of the aeration treatment is 5 Nm 3 / (m 2 h).

[0044] Example 5

[0045] The treatment method of this embodiment is the same as that of embodiment 2, except that in step (1), no catalyst is added and only electron beam irradiation treatment is used.

[0046] Comparative Example 1

[0047] 1L of the liquid to be treated was poured into a container of 1dm×1dm×1.5dm, and a 350W ultraviolet lamp was used to irradiate the container for 135 minutes.

[0048] Comparative Example 2

[0049] The treatment method of this comparative example is the same as that of Example 1, except that: instead of using electron beam to coordinate the catalyst irradiation treatment, only a 350W ultraviolet lamp is used to irradiate the container for 135 minutes, and aeration treatment is performed at the same time.

[0050] Comparative Example 3

[0051] The treatment method of this comparative example is the same as that of Example 1, except that the aerated gas in step (2) is air containing ozone, wherein the volume fraction of ozone is 15%.

[0052] The content of organic matter with a molecular weight greater than 5 KDa and the average molecular weight of organic matter in the solution to be treated and the solution treated by Examples 1 to 5 and Comparative Examples 1 to 3 were detected by gel chromatography and mass spectrometry, respectively. The results are shown in Table 1.

[0053] Table 1

[0054] Organic matter content greater than 5KDa (mg / L) Average molecular weight of organic matter (Da) Liquid to be treated 1700 23K Example 1 210 580 Example 2 468 860 Example 3 342 740 Example 4 380 760 Example 5 727 1890 Comparative Example 1 1020 17.5K Comparative Example 2 870 12.5K Comparative Example 3 386 780

[0055] From the data in the above table, it can be seen that the content of organic pollutants with a molecular weight greater than 5KDa and the average molecular weight of organic matter in the treated liquid after treatment by the methods of Examples 1 to 5 are significantly reduced. In particular, the content of organic pollutants with a molecular weight greater than 5KDa in Examples 1-4 is all below 470mg / L, and the average molecular weight of organic matter is all below 900Da, proving that the treatment method of the present invention can well degrade organic pollutants in sewage.

[0056] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0057] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A method for degrading organic pollutants, characterized in that: include: The sewage containing organic pollutants is irradiated with electron beams, and aeration treatment is performed at the bottom of the sewage, wherein the gas used in the aeration treatment is air.

2. The method for degrading organic pollutants according to claim 1, characterized in that: A catalyst is added during the electron beam irradiation.

3. The method for degrading organic pollutants according to claim 2, characterized in that: The catalyst is a multi-metal oxygen-containing material; wherein the metal includes at least one of magnesium, calcium, titanium, vanadium, chromium, manganese, molybdenum, tungsten, iron, cobalt, nickel and copper.

4. The method for degrading organic pollutants according to claim 2 or 3, characterized in that: The amount of catalyst added is 0.05-10 kg / m 3 .

5. The method for degrading organic pollutants according to claim 1, characterized in that: The irradiation dose of the electron beam is 0.5 to 30 kGy.

6. The method for degrading organic pollutants according to claim 1 or 5, characterized in that: The electron beam irradiation is performed in the form of pulse irradiation or continuous irradiation.

7. The method for degrading organic pollutants according to claim 1, characterized in that: The air contains nitrous oxide.

8. The method for degrading organic pollutants according to claim 7, characterized in that: The volume fraction of the nitrous oxide is 0.05-30%.

9. The method for degrading organic pollutants according to claim 1, 7 or 8, characterized in that: The intensity of the aeration treatment is 0.1 to 10 Nm 3 / (m 2 h).