WO2018045771A1

WO2018045771A1 - Integrated soil restoration photocatalytic reactor

Info

Publication number: WO2018045771A1
Application number: PCT/CN2017/083534
Authority: WO
Inventors: 李轶; 张弛; 郭燕飞; 李�杰; 吴文祥
Original assignee: 河海大学
Priority date: 2016-09-12
Filing date: 2017-05-09
Publication date: 2018-03-15
Also published as: CN106363016B; CN106363016A

Abstract

An integrated soil restoration photocatalytic reactor, a reactor shell thereof comprising a soil grinding chamber and a three-phase cyclic photocatalytic degradation chamber; the soil grinding chamber is connected to the three-phase cyclic photocatalytic degradation chamber, and a cutting blade (4) is rotatably connected to an inner wall of the soil grinding chamber so as to efficiently, rapidly, and uniformly grind soil; a soil inlet is opened on the inner wall of the soil grinding chamber, and a soil outlet is opened on a bottom wall of the three-phase cyclic photocatalytic degradation chamber; a spraying device is arranged above the three-phase cyclic photocatalytic degradation chamber, an aeration device is arranged below the chamber, and an ultraviolet LED light (8) is arranged in the middle; guide plates (6) are symmetrically arranged on both sides of the ultraviolet LED light (8) so that three phases of gas, liquid and solid may be uniformly mixed and may flow circularly; a surface of the guide plate (6) is coated with a photocatalyst titanium dioxide, thus solving the problem wherein a catalyst is difficult to recycle; the device integrates the functions of cutting and refining soil and photocatalytic restoration of soil, and has the advantages of a small area, a simple structure, a mild reaction condition, absence of secondary pollution, and an efficient and stable treatment effect.

Description

Integrated soil repair photocatalytic reactor

Technical field

The invention relates to an integrated soil repair photocatalytic reactor, and belongs to the technical field of soil remediation.

Background technique

Polycyclic aromatic hydrocarbons (PAHs) are a class of chemical compounds consisting of two or more aromatic rings (linear or clustered). They usually contain only carbon and nitrogen. However, elements such as nitrogen, sulfur and oxygen can enter the benzene ring through substitution reactions to form impurities. Acyclic aromatic compound. Polycyclic aromatic hydrocarbons are mainly produced by incomplete combustion and pyrolysis of organic matter. The sources can be divided into natural and anthropogenic sources. Natural sources include forest fires, volcanic eruptions, etc.; anthropogenic sources include motor vehicle exhaust emissions, residential wood combustion, and petroleum catalysis. Cracking, industrial fossil fuel combustion, etc. To date, more than 200 polycyclic aromatic hydrocarbons have been discovered, of which up to 28 have been identified as toxic and hazardous by the US Environmental Protection Agency (January 2008). The remarkable feature of these toxic substances is that they are highly hydrophobic and can be easily adsorbed onto the organic matter of the solid particles, thereby forming a persistent micro-contaminant in the environment. Studies have shown that soil is the main "reservoir" of polycyclic aromatic hydrocarbons.

Soils contaminated with polycyclic aromatic hydrocarbons pose potential risks to human and ecological health. The actual risk assessment of mutagenic and carcinogenic effects requires accurate exposure information, which is difficult to obtain in practice. Despite this, many countries, such as the Netherlands, Denmark, and Canada, have taken a precautionary measure to develop cleaning guidelines for soils contaminated with polycyclic aromatic hydrocarbons. However, most of the polycyclic aromatic hydrocarbons are characterized by low volatility and difficulty in biodegradation, and conventional methods such as soil gas phase extraction, biological ventilation, etc. cannot effectively remove them. Heterogeneous photocatalysis is considered to be an efficient method for soil cleaning. Among them, nano-titanium dioxide, such as commercial P25, has been widely introduced due to its high catalytic activity, strong oxidizing ability, good chemical stability, low price, and non-toxicity. Soil repair.

The rational design of photocatalytic reactor is one of the key technologies to realize the practical application of photocatalytic oxidation technology to repair soil. However, existing photocatalytic reactors for soil remediation have the following problems:

First, the power consumption is large: the plasma discharge photocatalytic reactor requires a high-voltage power supply system; the conventional photocatalytic reactor uses an ultraviolet mercury lamp, and the blast system has a large amount of aeration.

Second, photocatalyst and soil particles on the mass transfer effect of pollutants: research has shown that the size of soil particles have an important impact on the photocatalytic degradation efficiency of organic pollutants in the soil, smaller size soil particles and photocatalysts have more The large contact area has higher photocatalytic degradation efficiency; the conventional photocatalytic reactor uses magnetic stirring or paddle stirring, and does not fully contact the photocatalyst and soil contaminants.

Third, the photocatalyst recovery is difficult: the traditional photocatalytic reactor uses photocatalyst granule powder, which is difficult to separate from the soil particles, resulting in a large loss of photocatalyst, which will increase the operating cost and easily cause secondary pollution.

Fourth, the photocatalytic reaction conditions are harsh and the operation is cumbersome: Fenton photocatalytic reactor requires the reaction conditions to be acidic (best The pH is about 3), and iron sludge is easily generated in the reactor, and a subsequent treatment step is required.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the defects of the prior art, and provide an integrated soil repair photocatalytic reactor with integrated functions, energy saving, high efficiency and stability, no secondary pollution, convenient operation and mild reaction conditions. For the repair of polycyclic aromatic hydrocarbons contaminated soil.

In order to achieve the above object, the present invention provides an integrated soil remediation photocatalytic reactor, comprising: a reactor casing, a cutter, a shower device, a plurality of baffles, a plurality of LED lamps and an aeration device; The reactor casing comprises a soil pulverizing chamber and a three-phase circulating photocatalytic degradation chamber;

The soil pulverizing chamber is connected to the three-phase circulating photocatalytic degradation chamber, the cutter is rotatably connected to the inner wall of the soil pulverizing chamber, and an inner soil opening is formed on the inner wall of the soil pulverizing chamber, and the three-phase circulating light An outlet opening is defined in the bottom wall of the catalytic degradation chamber; the spraying device comprises a plurality of nozzles, a water inlet valve and a water pipe, the water inlet valve is disposed on the water pipe, and one end of the water pipe is connected to an external water body, the water pipe The other end is connected to a plurality of the nozzles, and the plurality of nozzles are symmetrically disposed on the inner wall of the three-phase circulating photocatalytic degradation chamber; and the plurality of LED lamps are symmetrically disposed in the three-phase circulating photocatalytic degradation chamber On the inner wall, a plurality of the baffles are symmetrically disposed on opposite sides of the plurality of LED lamps, and the baffles are rotatably connected to the inner wall of the three-phase circulating photocatalytic degradation chamber, and the deflector is provided with light. catalyst;

The aeration device is fixedly connected to the bottom wall of the three-phase circulating photocatalytic degradation chamber.

Preferentially, a first valve is also included; the first valve divides the reactor housing into the soil pulverizing chamber and the three-phase circulating photocatalytic degradation chamber.

Preferentially, the shower device further includes a water pump, a water tank, and a second flow meter; the water pump and the second flow meter are both disposed on the water pipe, and the water tank is connected to the plurality of places through the water pipe Said nozzle.

Preferentially, the aeration device includes an aeration plate, a first flow meter, an intake valve, a second air blower, and a gas pipe, and the intake valve and the first flow meter are both disposed on the gas pipe, An aeration plate is fixedly disposed on a bottom wall of the three-phase circulating photocatalytic degradation chamber, wherein the aeration plate is provided with a plurality of equally spaced pores, and the No. 2 blower communicates through the air pipe to the plurality of Stomata.

Preferentially, the second valve and the earthing pipe are further included; the shape of the earthing pipe is an inverted circular table, the earthing pipe is fixedly connected to the earth inlet, and the second valve is disposed on the earthing pipe and the soil Between the mouths.

Preferably, the excavation pipe and the third valve are further included; the excavation pipe is fixedly connected to the excavation port, and the third valve is disposed between the excavation pipe and the excavation opening.

Preferentially, the LED lamp is an ultraviolet LED lamp, and the cutter is a spiral cutter.

Preferentially, a first air blower is also included; the first blower communicates with the soil pulverizing chamber.

Preferentially, the bottom wall of the reactor casing is at an angle of 10°-45° to the ground, and the height of the bottom wall of the soil crushing chamber is higher than The three-phase cycle photocatalytic degradation of the bottom wall height of the chamber.

Preferentially, the outer side of the ultraviolet LED lamp is covered with a transparent quartz glass case.

The beneficial effects achieved by the invention:

(1) The device of the invention integrates the function of cutting refined soil and photocatalytic repairing soil, and the device of the invention has small floor space, simple structure, convenient operation, mild reaction condition, no secondary pollution, and the treatment effect is efficient and stable;

(2) Photocatalyst Titanium dioxide P25 is coated on the surface of the deflector, which solves the problem that the catalyst is difficult to recover, avoids the possibility of causing a large loss of photocatalyst, and reduces the operating cost of the present invention;

(3) The spiral cutter cuts the soil entering from the soil inlet into finely divided soil particles, reduces the content of the bulk soil in the soil, and is beneficial to increase the contact area between the subsequent soil particles and the photocatalyst, thereby improving the present invention. Catalytic efficiency; finely divided soil particles rely on water and gas carriers in a three-phase circulating photocatalytic degradation chamber, a spray device is arranged above the three-phase circulating photocatalytic degradation chamber, and an aeration device is arranged below, and an ultraviolet device is arranged in the middle The LED lamp has a baffle on both sides of the lamp. Under the action of the baffle, the gas-liquid-solid three-phase is uniformly mixed and circulated to form a three-phase circulating flow, which greatly improves the contact area between the soil and the photocatalyst. The pollutants are fully and uniformly mixed with the photocatalyst, which greatly improves the mass transfer efficiency;

(4) The invention adopts ultraviolet LED lamp, and has higher luminous efficiency, less power consumption and long service life compared with other common lamp sources such as incandescent lamp, fluorescent lamp, halogen tungsten lamp, etc.; the lamp tube shell is made of transparent quartz glass material. , which is beneficial to improving the illumination area of the ultraviolet LED lamp and improving the catalytic efficiency of the device of the invention;

(5) The bottom of the reactor shell has a certain slope, which can fully utilize the gravity to reduce the input of the wind, and saves the electric energy to a certain extent; according to the soil content that the reagent needs to be repaired, the water inlet is controlled by the inlet valve, and the intake water is passed through the intake valve. The valve adjusts the amount of aeration, so that the device of the invention can better repair the soil and improve the quality of repair.

DRAWINGS

Fig. 1 is a structural view of the present invention.

Figure 2 is a graph showing the effect of the apparatus of the present invention on the treatment of polycyclic aromatic hydrocarbons in soil.

The meanings of the symbols in the drawing, 1-1 valve; 2-2 valve; 3-introduction pipe; 4-cutting knife; 5-spray; 6-baffle; 7-quartz glass shell; 8-LED lamp; - aeration plate; 10 - unearthed pipe; 11 - No. 1 flow meter; 12 - water pump; 13 - water tank; 14 - intake valve; 15 - 2 blower; 16 - 3rd valve; 17 - 1 blower; 18-inlet valve; 19-second flow meter; 20-water pipe; 21-air pipe.

detailed description

The invention is further described below in conjunction with the drawings. The following examples are only intended to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of the present invention.

As shown in Figure 1, an integrated soil repair photocatalytic reactor includes a reactor housing, a cutter 4, a shower device, two baffles 6, an LED lamp 8 and an aeration device; the reactor housing includes Soil crushing chamber and three-phase circulating light The degradation chamber is provided; two reaction chambers are arranged in the outer casing, the soil inlet is connected to the soil crushing chamber, and the soil outlet is connected to the three-phase circulating photocatalytic degradation chamber.

The soil pulverizing chamber is connected to the three-phase circulating photocatalytic degradation chamber, and the cutter 4 is rotatably connected to the top wall of the soil pulverizing chamber, and the cutter 4 is a spiral cutter, which can be pulverized efficiently, quickly and uniformly. Soil granules; an inner soil opening is formed on an inner wall of the soil pulverizing chamber, and an earth outlet is opened on a bottom wall of the three-phase circulating photocatalytic degradation chamber;

The sprinkler device comprises two spray heads 5, a water inlet valve 18 and a water pipe 20, the water inlet valve 18 is disposed on the water pipe 20, one end of the water pipe 20 is connected to an external water body, and the other end of the water pipe 20 is connected to two The nozzles 5, two of the nozzles 5 are symmetrically disposed on the top wall of the three-phase circulating photocatalytic degradation chamber;

One of the LED lamps 8 is disposed on a top wall of the three-phase circulating photocatalytic degradation chamber, the LED lamp 8 is located at the center of the three-phase circulating photocatalytic degradation chamber, and the two baffles 6 are symmetrically disposed at On one side of one of the LED lamps 8, the baffle 6 is rotatably connected to the inner wall of the three-phase circulating photocatalytic degradation chamber, and the baffle 6 is provided with a photocatalyst, and the surface of the baffle is coated with Photocatalyst titanium dioxide (P25) solves the problem of difficult catalyst recovery;

Further, the first valve 1 is fixedly disposed between the soil grinding chamber and the three-phase circulating photocatalytic degradation chamber for controlling soil into the three-phase circulating photocatalytic degradation chamber. The amount.

Further, the shower device further includes a water pump 12, a water tank 13 and a second flow meter 19; the water pump 12 and the second flow meter 19 are all disposed on the water pipe 20, and the water tank 13 passes The water pipe 20 is connected to a plurality of the nozzles 5.

Further, the aeration device includes an aeration plate 9, a first flow meter 11, an intake valve 14, a second air blower 15 and a gas pipe 21, and the intake valve 14 and the first flow meter 11 are both disposed at The aeration plate 9 is fixedly disposed on a bottom wall of the three-phase circulating photocatalytic degradation chamber, and the aeration plate 9 is provided with a plurality of equally spaced pores, the second The air blower 15 communicates a plurality of the air holes through the air pipe 21.

The three-phase circulating photocatalytic degradation chamber is provided with a spraying device above, and an aeration device is arranged below, and an ultraviolet LED lamp is arranged in the middle, and a deflector is arranged on both sides of the lamp, so that the gas-liquid solid three-phase is uniformly mixed and circulated flow.

Further, the second valve 2 and the earthing pipe 3 are further included; the shape of the earthing pipe 3 is an inverted circular table, the earthing pipe 3 is fixedly connected to the earth inlet, and the second valve 2 is disposed at the earth pipe 3 and between the earth inlets.

Further, the excavation pipe 10 and the third valve 16 are further included; the excavation pipe 10 is fixedly connected to the earthing opening, and the third valve 16 is disposed between the excavation pipe 10 and the earthing opening.

Further, the LED lamp 8 is an ultraviolet LED lamp, and the outer side of the ultraviolet LED lamp is covered with a transparent quartz glass shell; the light source body is an ultraviolet LED lamp, and is similar to other common light sources such as incandescent lamps, fluorescent lamps, tungsten halogen lamps, and the like. Compared with its high luminous efficiency, low power consumption and long service life; the lamp tube shell is made of transparent quartz glass 7, which is the best for all UV-permeable materials. By.

Further, a first air blower 17 is further included; the first air blower 17 communicates with the soil crushing chamber.

Further, the bottom wall of the reactor shell is at an angle of 30° to the ground, the height of the bottom wall of the soil pulverizing chamber is higher than the height of the bottom wall of the three-phase circulating photocatalytic degradation chamber, and the bottom of the reactor shell has a certain slope. It can make full use of gravity to reduce the input of wind and save energy.

The finely divided soil particles divided by the cutter can form a three-phase circulating flow under the action of the baffle 6 in the photocatalytic degradation chamber, and the pollutants are fully uniformly mixed with the photocatalyst, thereby greatly improving the particle size. Its mass transfer efficiency.

The working process of the device of the present invention: sampling respectively at the soil inlet and the soil outlet of the present invention, taking three repeated soil samples for each mouth, taking soil samples every other day, and the apparatus of the present invention continues to run for 5 days and then ends sampling. Three common polycyclic aromatic hydrocarbon compounds, phenanthrene, anthracene and benzoindole, were selected as representative. The results of the examples show that the removal efficiency of polycyclic aromatic hydrocarbons in the soil by the integrated soil-repaired photocatalytic reactor is shown in Fig. 2. More than 80%, 90% and 95% respectively. Moreover, in continuous repeated experiments, the removal efficiency fluctuated little and the effect was stable.

The above is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention. It should also be considered as the scope of protection of the present invention.

Claims

An integrated soil repair photocatalytic reactor, comprising: a reactor shell, a cutter (4), a shower device, a plurality of baffles (6), a plurality of LED lamps (8) and an aeration device; The reactor shell comprises a soil pulverizing chamber and a three-phase circulating photocatalytic degradation chamber;

The soil pulverizing chamber is connected to the three-phase circulating photocatalytic degradation chamber, the cutter (4) is rotatably connected to the inner wall of the soil pulverizing chamber, and an inner soil opening is formed on the inner wall of the soil pulverizing chamber. An earth outlet is opened on the bottom wall of the phase cycle photocatalytic degradation chamber;

The spraying device comprises a plurality of nozzles (5), a water inlet valve (18) and a water pipe (20), the water inlet valve (18) is disposed on the water pipe (20), and one end of the water pipe (20) Connecting the external water body, the other end of the water pipe (20) is connected to a plurality of the nozzles (5), and the plurality of nozzles (5) are symmetrically disposed on the inner wall of the three-phase circulating photocatalytic degradation chamber;

A plurality of the LED lamps (8) are symmetrically disposed on an inner wall of the three-phase circulating photocatalytic degradation chamber, and a plurality of the deflectors (6) are symmetrically disposed on two sides of the plurality of LED lamps (8). The baffle (6) is rotatably connected to an inner wall of the three-phase circulating photocatalytic degradation chamber, and the baffle (6) is coated with a photocatalyst;

The aeration device is fixedly connected to the bottom wall of the three-phase circulating photocatalytic degradation chamber.
The integrated soil remediation photocatalytic reactor according to claim 1, further comprising a first valve (1); said first valve (1) separating said reactor casing into said soil pulverizing chamber And the three-phase circulating photocatalytic degradation chamber, the soil pulverizing chamber is located on the left side of the three-phase circulating photocatalytic degradation chamber.
The integrated soil remediation photocatalytic reactor according to claim 1, wherein the sprinkler device further comprises a water pump (12), a water tank (13) and a second flow meter (19); 12), the second flow meter (19) is disposed on the water pipe (20), and the water tank (13) is connected to the plurality of the nozzles (5) through the water pipe (20).
The integrated soil repair photocatalytic reactor according to claim 1, wherein the aeration device comprises an aeration plate (9), a first flow meter (11), an intake valve (14), and a second a blower (15) and a gas pipe (21), the intake valve (14) and the first flow meter (11) are disposed on the gas pipe (21), and the aeration plate (9) is fixedly disposed at The bottom wall of the three-phase circulating photocatalytic degradation chamber is provided with a plurality of equally spaced pores on the aeration plate (9), and the second blower (15) is connected through the gas pipe (21). The stomata.
The integrated soil remediation photocatalytic reactor according to claim 1, further comprising a second valve (2) and an earth inlet pipe (3); wherein the inlet pipe (3) has an inverted truncated cone shape, The earthing pipe (3) is fixedly connected to the earth inlet, and the second valve (2) is disposed between the earthing pipe (3) and the earth inlet.
The integrated soil remediation photocatalytic reactor according to claim 1, further comprising an excavation pipe (10) and a third valve (16); the excavation pipe (10) fixedly connecting the excavation port, The third valve (16) is disposed between the excavation pipe (10) and the earthing opening.
The integrated soil repair photocatalytic reactor according to claim 1, wherein the LED lamp (8) is an ultraviolet LED lamp, and the cutter (4) is a spiral cutter.
The integrated soil remediation photocatalytic reactor according to claim 1, further comprising a first air blower (17); said first air blower (17) communicating with said soil pulverizing chamber.
The integrated soil remediation photocatalytic reactor according to claim 2, wherein the bottom wall of the reactor casing is at an angle of 10° to 45° with respect to the ground, and the height of the bottom wall of the soil pulverizing chamber is higher than The three-phase cycle photocatalytic degradation of the bottom wall height of the chamber.
The integrated soil repair photocatalytic reactor according to claim 7, characterized in that the outer side of the ultraviolet LED lamp is covered with a transparent quartz glass shell (7).