CN114132991A

CN114132991A - Equipment for activating persulfate by using acoustic-gas coupling driving iron-like carbon packed bed and method for treating wastewater by using equipment

Info

Publication number: CN114132991A
Application number: CN202111436837.7A
Authority: CN
Inventors: 尤宏; 徐祺辉; 李之鹏; 柳锋; 李昊阳
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2021-11-29
Filing date: 2021-11-29
Publication date: 2022-03-04
Anticipated expiration: 2041-11-29

Abstract

The invention relates to the technical field of environmental science and engineering, in particular to equipment for activating persulfate by using an acoustic-gas coupling driving iron-like carbon packed bed and a method for treating wastewater by using the same. Comprises an inverted cone-shaped reactor, a ventilation unit, a pipeline mixer and an ultrasonic vibrating rod; the inverted cone-shaped reactor is provided with a water outlet and a movable bed body; the pipeline mixer is provided with a dosing port and a water inlet; the effective area of the ultrasonic vibration rod is inserted into the movable bed body. The reaction active area is controlled by adjusting the positions of the upper washer and the lower washer; a composite catalytic oxidation system is formed through a simple dosing port and an aeration system; the rod-shaped ultrasonic drive activation system is utilized to remove an oxidation layer generated by passivation of iron-carbon particle fillers, and the iron-carbon micro-electrolysis composite persulfate oxidation system is effectively coupled to treat wastewater. The device is easy to build and finished, can meet the sewage and wastewater treatment requirements in multiple scenes, and is convenient for popularization of the advanced oxidation technology based on sound-gas catalysis.

Description

Equipment for activating persulfate by using acoustic-gas coupling driving iron-like carbon packed bed and method for treating wastewater by using equipment

Technical Field

The invention relates to the technical field of environmental science and engineering, in particular to equipment for activating persulfate by using an acoustic-gas coupling driving iron-like carbon packed bed and a method for treating wastewater by using the same.

Background

The treatment method of the refractory organic wastewater comprises a physical method, a chemical method and a biological method. The biological treatment method has the advantages of simple equipment and low operating cost, and is widely applied to wastewater treatment, but the equipment occupies a large area, has a long treatment period, particularly has a difficult-to-degrade organic matter, is difficult to achieve a good treatment effect by adopting a common biological method, needs to domesticate special strains, and is relatively complex to treat. However, the traditional physical and chemical methods such as flocculation and gas stripping only transfer the pollutants from the liquid phase to the solid phase or the gas phase, but do not completely eliminate the organic pollutants, thereby causing the problems of secondary pollution and the like. Therefore, the chemical method is a main treatment method of the organic wastewater difficult to degrade in the prior art.

In the chemical method for treating the organic wastewater difficult to degrade, a persulfate activation technology based on sulfate radicals is a novel oxidation technology developed in recent years, and the application of the technology in the field of environment is more and more extensive. In the prior art, abundant research on persulfate activation is carried out, and many technologies are put into practical engineering application and used as a certain link in practical wastewater treatment, such as greatly reducing the chemical oxygen demand value of effluent, improving subsequent biodegradability, or destroying a difficultly biodegradable macromolecular compound (such as existing in secondary effluent; represented by medicines, personal care products and endocrine disruptors) into a micromolecular compound which is easy to biochemically or mineralize; in the environmental remediation, the in-situ and ex-situ remediation of sites (including soil and underground water) polluted by organic matters (such as total petroleum hydrocarbons, volatile organic matters and semi-volatile organic matters) is performed, and meanwhile, the in-situ and ex-situ remediation also has a certain effect on light non-aqueous phase liquid in the underground water. However, persulfate has a relatively slow reaction rate at normal temperature and has an insignificant degradation effect on organic substances, and the catalysis/activation of persulfate mainly comprises a physical method and a chemical method, wherein the chemical method comprises a nonmetal base, a metal base, an organic covalent metal compound, a composite material (such as nonmetal-metal), an oxidant and the like. Wherein the metal base comprises a zero valent metal, a (mono, di, poly) metal oxide or compound; physical means such as sound, light, heat, and microwave, etc. Persulfate can degrade most organic matters under the conditions of heat, light, transition metal ions and the like. However, the method for activating persulfate by heat, light and transition metal ions has complex system, harsh operating conditions and high cost, and prevents the application of persulfate technology in organic wastewater treatment.

The ultrasound generally interacts with a medium in the form of longitudinal waves in a transmission process, so that the medium is subjected to physical or chemical changes, and acoustic effects are generated, wherein the acoustic effects mainly comprise mechanical effects, thermal effects, cavitation effects and secondary effects caused by the mechanical effects. The ultrasonic equipment is simple, convenient to operate, clean and free of secondary pollution, and belongs to an environment-friendly type, but the ultrasonic exists in an 'auxiliary' form in the aspect of environmental remediation all the time, compared with photocatalysis, acoustic catalysis is less concerned, and the research on the effect of the ultrasonic in catalytic activation of an oxidant in the system exposition in the prior art is insufficient. Particularly, after the intermediate medium is added, how to effectively utilize the physical and chemical effects of the acoustic catalysis on the intermediate medium so as to deeply excavate the potential effect of the ultrasound in the environmental catalysis is beneficial to popularization of the application of the acoustic catalysis. Therefore, it is necessary to design a corresponding reaction system and equipment so as to exert the synergistic effects of ultrasonic catalysis, oxidant activation and catalyst catalysis, so as to effectively and deeply treat wastewater.

Disclosure of Invention

Based on the above, the invention provides a device for activating persulfate by using an acoustic-gas coupling driven iron-like carbon packed bed and a method for treating wastewater by using the device.

One of the technical schemes of the invention is equipment for activating persulfate by using an acoustic-gas coupling driving iron-like carbon packed bed, which comprises an inverted cone cylindrical reactor, a ventilation unit arranged at the bottom of the inverted cone cylindrical reactor, a pipeline mixer communicated with one side of the bottom of the inverted cone cylindrical reactor and an ultrasonic vibrating rod inserted from the top of the inverted cone cylindrical reactor;

a water outlet is formed in one side of the upper part of the inverted cone-shaped reactor, and a movable bed body is arranged below the water outlet;

the ultrasonic vibrating bar is connected with an ultrasonic generator, and the pipeline mixer is provided with a dosing port and a water inlet;

the effective area of the ultrasonic vibration rod is inserted into the movable bed body;

the aeration unit comprises an aeration head and a gas generator, wherein the aeration head is arranged on the inner side of the bottom of the inverted cone-shaped reactor, and the gas generator is arranged on the outer side of the bottom of the inverted cone-shaped reactor.

The gas generator is used for providing a gas source, and the gas source is air or ozone.

Furthermore, the number of the aeration heads is more than 1, the arrangement of the aeration heads enables pneumatic stirring to be formed in the equipment for activating persulfate by the acoustic-air coupling driving iron-like carbon packed bed, and a plurality of aeration heads can form an aeration group, so that the pneumatic stirring effect is better. Meanwhile, a plurality of aeration heads are arranged to provide different air sources through different air generators, so that the system oxidation effect is improved, the mass transfer degree is increased and controlled, and the wastewater treatment effect is enhanced.

Further, the inverted cone cylindrical reactor and the aeration unit are communicated through a lower connecting flange, the ultrasonic vibration rod is fixed to the top of the inverted cone cylindrical reactor through an upper connecting flange, and the aeration head is modified through load.

Further, the load modification is micro-nano catalyst load modification.

The load modification can be hydrothermal load of nano metal oxide, taking ZnO as an example, and utilizing a classical hydrothermal method: 0.5g of hexamethylenetetramine, 1g of zinc acetate hexahydrate and a titanium aeration head are mixed in 60mL of deionized water, the aeration head is downward, hydrothermal is carried out for 3 hours at 90 ℃, and after drying, calcination is carried out for 2 hours at 450 ℃.

Further, in order to flexibly control the size of the fixed bed, the movable bed body comprises an upper gasket, a lower gasket and a filler arranged between the upper gasket and the lower gasket, and a hole for inserting an ultrasonic vibration rod is formed in the center of the upper gasket.

Further, the movable bed body is moved and zoomed by the upper gasket and the lower gasket, the upper gasket and the lower gasket are in a porous structure, and the filler is iron-carbon particle filler, including but not limited to commercial iron-carbon particles, and also can be self-made modified iron-carbon particle materials, sponge iron, scrap iron and the like.

The second technical scheme of the invention is a method for treating wastewater, which uses the equipment for activating persulfate by using the acoustic-gas coupling driving iron-like carbon packed bed to treat wastewater.

Further, the method specifically comprises the following steps:

the wastewater enters a pipeline mixer through a water inlet (the water inlet flow rate is 20-40mL/min, the persulfate enters the pipeline mixer through a chemical adding port, and the wastewater and the persulfate solution are uniformly mixed in the pipeline mixer, then enter an inverted cone-shaped reactor and gradually permeate into a movable bed body; and opening the gas generator and the ultrasonic generator, blowing gas into the wastewater through the aeration head, and discharging the wastewater from the water outlet after the wastewater stays in the movable bed body for acoustic catalysis/activation treatment.

Further, adding a medicament into the medicament adding port to adjust the pH value of the wastewater to 3-6, wherein the mass ratio of the concentration of the pollutants in the wastewater to the persulfate is 5-15mg:0.5 g.

Further, the gas blown into the wastewater by the aeration head is air or ozone, and the ventilation quantity is 0-1L/min.

Further, the retention time of the wastewater in the movable bed body is 30-60 min.

Further, the ultrasonic frequency of the ultrasonic generator is 20-40 kHz.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, the ultrasonic vibration rod is inserted into the movable bed body, the ultrasonic self has cavitation effect, mechanical effect, thermal effect and the like and can be used for treating wastewater, the iron carbon is driven by the ultrasonic to activate the persulfate oxidant, and an active intermediate is generated and can be used for deeply treating polluted wastewater; under the condition of keeping a certain hydraulic retention time, the iron carbon has an iron carbon micro-electrolysis effect, and the polluted wastewater can be further treated in a coupling way; the mechanical effect produced by the ultrasound can remove (T) the oxide layer of the iron carbon particle filler in the treatment process due to the passivation of the oxidant, and provides better interface contact between fresh iron carbon and the liquid phase. An aeration head is arranged in the inverted cone-shaped cylindrical reactor to provide bubbles to promote ultrasonic cavitation, and simultaneously, the effect of catalytic oxidation of a system can be coupled and enhanced.

The invention has certain elasticity, and the position and the size of the catalytic fixed bed can be controlled by flexibly adjusting the positions of the upper gasket and the lower gasket so as to control the reaction active area; the construction of a multielement advanced oxidation system can be completed through a simple medicine adding port and an aeration system to form a composite catalytic oxidation system; the rod-shaped ultrasonic drive activation system is utilized to remove an oxidation layer generated by passivation of iron-carbon particle fillers, provide better interface contact between fresh iron-carbon and a liquid phase, and effectively couple the iron-carbon micro-electrolysis composite persulfate oxidation system to treat wastewater. The equipment and the method can be operated in an enlarged mode and also can be treated in a small mode, are easy to build and finished, can meet the sewage and wastewater treatment requirements in multiple scenes, and are convenient for popularization of the advanced oxidation technology based on sound-gas catalysis.

Drawings

FIG. 1 is a schematic view showing the structure of an apparatus used in example 1 of the present invention, wherein 1-an inverted conical reactor, 2-a movable bed, 3-an upper gasket, 4-a lower gasket, 5-an aeration unit, 6-an aeration head, 7-a gas generator, 8-a lower flange, 9-a pipeline mixer, 10-a chemical feed port, 11-a water inlet, 12-a water outlet, 13-an ultrasonic generator, 14-an ultrasonic vibrating rod, and 15-an upper flange; the upper left figure is a scanning electron microscope image T of the iron-carbon filler T; the lower left figure is iron carbon filler T.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The description and examples are intended to be illustrative only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

Example 1

Fig. 1 is a device for activating persulfate by using an acoustic-gas coupling catalytic iron-carbon packed bed for wastewater treatment in this embodiment, which specifically includes:

the device comprises an inverted cone-shaped reactor 1, an aeration unit 5 arranged at the bottom of the inverted cone-shaped reactor 1, a pipeline mixer 9 (which can avoid the loss of a medicament caused by top dosing) communicated with one side of the bottom of the inverted cone-shaped reactor 1, and an ultrasonic vibrating rod 14 inserted from the top of the inverted cone-shaped reactor 1;

a water outlet 12 is formed in one side of the upper part of the inverted cone-shaped reactor 1, and a movable bed body 2 is arranged below the water outlet 12; the ultrasonic vibration rod 14 is connected with an ultrasonic generator 13 (coupled with iron carbon to activate persulfate so as to generate a driving activation effect), the pipeline mixer 9 is provided with a dosing port 10 (the dosing port 10 can be a multi-dosing port, so that different types and different ratios of medicaments, including different oxidants, acid and alkali required for adjusting pH or some redox regulators, can be pumped according to requirements) and a water inlet 11; the effective area of the ultrasonic vibration rod 14 is inserted into the movable bed body 2 (persulfate is activated by coupling iron carbon to generate driving activation effect);

the aeration unit 5 comprises an aeration head 6 and a gas generator 7, wherein the aeration head 6 is arranged at the inner side of the bottom of the inverted cone-shaped reactor 1 (the number of the aeration heads 6 can be 1 or more), and the gas generator 7 is arranged at the outer side of the bottom of the inverted cone-shaped reactor 1 (when a plurality of aeration heads are arranged, each aeration head corresponds to one gas generator which can be used for generating different gases, can form aeration groups, can form pneumatic stirring, and can increase and control the mass transfer degree) (the aeration heads can also be subjected to load modification, such as hydrothermal load of nano metal oxide, taking ZnO as an example, and by using a classical hydrothermal method, namely mixing 0.5g of hexamethylenetetramine, 1g of zinc acetate hexahydrate and a titanium aeration head in 60mL of deionized water, the aeration heads face down, hydrothermal at 90 ℃ for 3h, and after drying, calcining at 450 ℃ for 2 h).

Back taper column form reactor 1 with ventilation unit 5 is through 8 intercommunications of lower flange, the supersound shakes excellent 14 and fixes through last flange back taper column form reactor 1 top, activity bed body 2 includes packing ring 3, lower packing ring 4 and sets up go up packing ring 3 with packing T between the

lower packing ring

4, 3 centers of going up packing ring are equipped with and are used for the supersound to shake excellent 14 male holes (the adaptation supersound of being convenient for shakes the insertion of excellent to stabilize the supersound and shake excellent position). The movable bed body 2 can be moved and zoomed through the upper gasket 3 and the lower gasket 4 (the size of the fixed bed can be flexibly controlled, and different wastewater treatment needs can be met), the upper gasket 3 and the lower gasket 4 are of a porous structure, and the upper left figure is a scanning electron microscope image T of the iron-carbon filler T; the lower left panel shows an iron-carbon filler T (commercial iron-carbon particles, modified iron-carbon granular materials, sponge iron, scrap iron, etc., which are used in the present example, all have the effect of enhancing the activation of the fixed bed zone).

The wastewater treatment is carried out by using the equipment (the wastewater source is refractory organic wastewater, the main pollutant is triphenylmethane derivative crystal violet, the concentration is about 400mg/L, the initial COD is 600mg/L, and the initially pumped waste liquid is nearly neutral 6-7), and the specific steps are as follows:

the waste liquid to be treated enters a pipeline mixer 9 through a water inlet 11 (the water inflow flow rate is 40mL/min), a high-concentration sodium persulfate solution is pumped through a medicine adding port 10 (the mass ratio of the pollutant concentration in the waste water to the sodium persulfate is 15mg:0.5g, 1mol/L of sodium persulfate is pumped into a system at the flow rate of 1 mL/min), the aqueous solution is kept alkaline in the process, if the aqueous solution is alkaline, a medicine is added through the medicine adding port 10, the pH value is adjusted to 3-4, the mixture is fully mixed through the pipeline mixer 9, then the mixture enters an inverted cone-shaped reactor 1 and gradually overflows into a movable bed body 2 filled with iron-carbon particle fillers T; the ultrasonic generator 13 and the gas generator 7 are switched on to generate sound and gas actions (ultrasonic frequency 28kHz), respectively. The ultrasonic self has cavitation effect, mechanical effect, thermal effect and the like and can be used for treating wastewater, the iron carbon is driven by the ultrasonic to activate persulfate oxidizer, effective acoustic catalysis/activation is carried out in a movable bed area, and active intermediates such as sulfate radicals and hydroxyl radicals are generated to deeply treat polluted wastewater; under the hydraulic retention time of 60min, the iron carbon has the iron carbon micro-electrolysis effect, and the polluted wastewater can be further treated in a coupling way; the mechanical effect generated by the ultrasonic can remove an oxidation layer generated by the passivation of an oxidant in the treatment process of the iron-carbon particle filler T, provide better interface contact between fresh iron-carbon and a liquid phase, and promote three-phase mass transfer; the types of gas entering the liquid phase, such as air, ozone, gas amount and the like (nitrogen is used in the embodiment, the gas amount is controlled to be 1L/min) are controlled through the aeration head 6, pneumatic stirring is provided, mass transfer is enhanced, bubbles are provided to promote ultrasonic cavitation, and the effect of catalytic oxidation of a system is enhanced in a coupling mode; the treated wastewater is discharged through the water outlet 12. The water flowing out of the water outlet 12 is detected again, alkali is added to about pH 8 before the water sample is detected, and coagulation sedimentation is performed, and the result shows that: the theoretical COD removal rate is 75 percent, and the removal rate of the triphenylmethane derivative crystal violet is more than 90 percent.

Example 2

The difference from example 1 is that, when wastewater treatment was carried out, the ultrasonic generator was not turned on, and the results showed that: compared with the example 1, the theoretical COD removal rate is reduced by 15 to 20 percent.

Example 3

The difference from example 1 is that, when wastewater treatment was carried out, the aeration unit was not turned on, and the results showed that: compared with the example 1, the theoretical COD removal rate is reduced by 10 to 15 percent.

Example 4

The difference from example 1 is that, when wastewater treatment was performed, the ultrasonic generator and the aeration unit were not turned on, and the results showed that: compared with the example 1, the theoretical COD removal rate is reduced by 20 to 30 percent.

Example 5

The difference from example 1 is that, when wastewater treatment was carried out, ozone was used as a gas source, and the concentration of ozone was 30mg/L, and the results showed that: compared with the embodiment 1, the theoretical COD removal rate of the effluent is improved by 15-30 percent.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The equipment for activating the persulfate by using the acoustic-gas coupling driving iron-like carbon packed bed is characterized by comprising an inverted cone cylindrical reactor (1), a ventilation unit (5) arranged at the bottom of the inverted cone cylindrical reactor (1), a pipeline mixer (9) communicated with one side of the bottom of the inverted cone cylindrical reactor (1) and an ultrasonic vibrating rod (14) inserted from the top of the inverted cone cylindrical reactor (1);

a water outlet (12) is formed in one side of the upper part of the inverted cone-shaped reactor (1), and a movable bed body (2) is arranged below the water outlet (12);

the ultrasonic vibrating bar (14) is connected with an ultrasonic generator (13), and the pipeline mixer (9) is provided with a dosing port (10) and a water inlet (11);

the effective area of the ultrasonic vibration rod (14) is inserted into the movable bed body (2);

the aeration unit (5) comprises an aeration head (6) and a gas generator (7), wherein the aeration head (6) is arranged on the inner side of the bottom of the inverted conical cylindrical reactor (1), and the gas generator (7) is arranged on the outer side of the bottom of the inverted conical cylindrical reactor (1).

2. The apparatus for activating the persulfate according to the claim 1, wherein the inverted conical reactor (1) and the aeration unit (5) are communicated through a lower flange (8), the ultrasonic vibration rod (14) is fixed at the top of the inverted conical reactor (1) through an upper flange, and the aeration head is modified by load.

3. The apparatus for activating persulfate according to claim 1, wherein the movable bed body (2) comprises an upper washer (3), a lower washer (4) and a filler T arranged between the upper washer (3) and the lower washer (4), and the upper washer (3) is provided with a hole in the center for inserting an ultrasonic vibrating rod (14).

4. The apparatus for activating persulfate according to claim 3, wherein the movable bed (2) is moved and scaled by the upper washer (3) and the lower washer (4), the upper washer (3) and the lower washer (4) are porous structures, and the filler T is iron-carbon particle filler.

5. A method for treating wastewater, which is characterized in that the wastewater treatment is carried out by using the device for activating persulfate by using the acoustic-gas coupling driven iron-like carbon packed bed as claimed in any one of claims 1 to 4.

6. A method of treating wastewater according to claim 5 and comprising the steps of:

wastewater enters a pipeline mixer (9) through a water inlet (11), persulfate enters the pipeline mixer (9) through a chemical adding port (10), and the wastewater and persulfate solution are uniformly mixed in the pipeline mixer (9), then enter an inverted cone column reactor (1) and gradually permeate into a movable bed body (2);

the gas generator (7) and the ultrasonic generator (13) are turned on, gas is blown into the wastewater through the aeration head (6), and the wastewater stays in the movable bed body (2) for acoustic catalysis/activation treatment and then is discharged from the water outlet (12).

7. The method for treating wastewater according to claim 6, further comprising adding a medicament into the medicament adding port (10) to adjust the pH value of the wastewater to 3-6, wherein the mass ratio of the concentration of the pollutants in the wastewater to the persulfate is 5-15mg:0.5 g.

8. The method of treating wastewater according to claim 6, wherein the gas blown into the wastewater by the aeration head (6) is air or ozone, and the aeration amount is 0 to 1L/min.

9. A method for treating wastewater according to claim 6, characterized in that the residence time of said wastewater in the movable bed (2) is 30-60 min.

10. A method for treating wastewater according to claim 6, characterized in that the ultrasonic frequency of said ultrasonic generator (13) is 20-40 kHz.