CN107555528B - Integrated mechanical photocatalytic membrane separation coupling reactor and wastewater treatment method thereof - Google Patents

Abstract

The invention discloses an integrated mechanical photocatalytic membrane separation coupling reactor, which comprises a water inlet area, a mixing area, a reaction area and a water outlet area; the water inlet area is provided with a water inlet; the mixing zone at least comprises a mixing zone side wall and a bottom, the mixing zone side wall can move up and down relative to the bottom, a mechanical stirrer is arranged in the mixing zone, the mixing zone is communicated with the water inlet zone through the bottom of the mixing zone, and the mixing zone is sealed and isolated from the reaction zone through the mixing zone side wall; the reaction zone at least comprises a reaction zone side wall, a filtering membrane is arranged on the reaction zone side wall, an ultraviolet lamp is arranged in the reaction zone, and the reaction zone at least surrounds the lower part of the mixing zone side wall; the side wall of the reaction zone separates the reaction zone from the water outlet zone, and the water outlet zone is provided with a water collecting pipe. The invention also discloses a method for treating wastewater by using the integrated mechanical photocatalytic membrane separation coupling reactor. The reactor disclosed by the invention is high in integration degree, convenient to carry, convenient to operate, low in production cost, high in photocatalyst use efficiency and good in application prospect.

Description

Integrated mechanical photocatalytic membrane separation coupling reactor and wastewater treatment method

technical field

The invention relates to the technical field of wastewater treatment, in particular to an integrated mechanical photocatalytic membrane separation coupling reactor and a wastewater treatment method thereof.

Background technique

In recent years, due to the needs of industrial and economic development, many industrial wastewaters containing toxic substances are continuously discharged into the environment, and the toxic substances are difficult to biodegrade, which brings great harm to industrial and agricultural production, people's life and human health. How to effectively deal with these wastewaters that cause environmental pollution has become a research hotspot in the environmental field. Photocatalytic oxidation technology is a new type of water pollution control technology, which has the characteristics of high efficiency, energy saving and wide application. Among them, the use of photocatalysts has two forms, one is fixed on a carrier (ie, a supported catalyst), and the other is suspended and dispersed in a solution (ie, a suspended catalyst). For supported catalysts, the mass transfer process of pollutants to the catalyst surface is limited, which reduces the photocatalytic efficiency. The suspended catalyst has a uniform distribution, a large surface area, and a higher catalytic efficiency, but the fine photocatalyst particles are not easy to be separated and recovered by the traditional separation technology, and the reuse rate is low, and the discharged liquid is prone to secondary pollution, which seriously limits its application.

Membrane separation technology is a new type of separation and purification technology that has developed rapidly in recent years. In the process of water treatment, the purpose of separating pollutants in concentrated water is achieved through the retention of micropores on the membrane surface. Generally, there is no phase change and secondary pollution during the membrane separation process, and it can be operated continuously at room temperature. It has low energy consumption and equipment It has the advantages of small size and convenient operation. However, the problem of membrane fouling leads to a decrease in membrane flux and shortens the service life of membranes. Although certain research progress has been made in controlling membrane fouling, it is still the main bottleneck in the development of membrane separation technology.

Photocatalytic oxidation technology and membrane separation technology have their own advantages, but they also have their own shortcomings. There are few cases of combining the two in the water treatment industry, and the photocatalytic-membrane separation technology is not mature enough. Therefore, the existing technology still needs to be improved and developed.

Photocatalytic oxidation technology and membrane separation technology have their own advantages, but they also have their own shortcomings. There are few cases of combining the two in the water treatment industry, and the photocatalytic-membrane separation technology is not mature enough. Therefore, the existing technology still needs to be improved and developed.

SUMMARY OF THE INVENTION

Purpose of the invention: The purpose of the present invention is to provide a kind of photocatalytic membrane device that can overcome the problems that the existing photocatalytic membrane device is complicated in structure, the solid photocatalyst in the reactor is difficult to separate, and the membrane life is short, the service life is long, the cost is low, and the integration degree is high. photocatalytic-membrane separation reactor.

Another object of the present invention is to provide a method for treating wastewater which can efficiently remove trace organics in water and has simple backwashing procedure.

Technical scheme: The present invention provides an integrated mechanical photocatalytic membrane separation and coupling reactor, which includes a water inlet area, a mixing area, a reaction area and a water outlet area; the water inlet area is provided with a water inlet; the mixing area at least includes the side wall of the mixing area and the bottom, the side wall of the mixing zone can move up and down relative to its bottom, a mechanical stirrer is arranged in the mixing zone, the mixing zone is communicated with the water inlet zone through its bottom, and the mixing zone is sealed and isolated from the reaction zone through the side wall of the mixing zone; the reaction zone It includes at least a side wall of the reaction zone, a filter membrane is arranged on the side wall of the reaction zone, an ultraviolet lamp is arranged in the reaction zone, and the reaction zone at least surrounds the lower part of the side wall of the mixing zone; the side wall of the reaction zone separates the reaction zone from the water outlet, and the outlet There is a water collection pipe in the area.

In order to improve the wastewater treatment efficiency of the reactor and reduce the volume of the reactor, the mixing area, the reaction area and the water outlet area are in the shape of concentric sleeves arranged in sequence from the inside to the outside, and the water inlet area is arranged in the mixing area, the reaction area and the water outlet area. below.

In order to fully mix the waste water and the catalyst in the mixing zone, the bottom of the mixing zone is set as a conical structure protruding to the lower side of the mixing zone, and a plurality of water inlet holes are evenly distributed; the bottom of the mixing zone is inclined relative to the bottom of the water inlet zone The angle is 25-35°, and the lower end of the bottom of the mixing zone is in contact with the bottom of the water inlet zone. Such a structure is conducive to the formation of a circulating flow of waste water, so as to be fully mixed with the catalyst in the mixing zone.

In order to improve the photocatalytic reaction efficiency in the reaction zone, a plurality of ultraviolet lamps arranged in parallel around the mixing zone are arranged in the reaction zone. The wavelength of the light emitted by the ultraviolet lamps is 253.7 nm, and a quartz protective sleeve is arranged outside the ultraviolet lamps; in order to reduce the reaction time The temperature of the zone can be improved to improve the reaction efficiency, and the quartz protective sleeve is respectively coiled with a cooling coil.

In order to efficiently separate the solid catalyst and waste water and improve the stability of the filter membrane, the side wall of the reaction zone includes a support plate and a filter membrane arranged close to the support plate. 0.01 to 0.03 microns.

Another aspect of the present invention provides a method for treating wastewater using the above-mentioned integrated mechanical photocatalytic membrane separation and coupling reactor, comprising: adding a photocatalyst into the mixing zone through the top of the mixing zone, and injecting the waste water into the reactor from a water inlet, The waste water enters the mixing zone through the bottom of the mixing zone, the mechanical agitator is turned on to mix the waste water and the photocatalyst evenly, the ultraviolet lamp is turned on, and the side wall of the mixing zone is pulled upward, so that the mixture of the waste water and the photocatalyst enters the reaction zone for photocatalysis. reaction.

The photocatalyst is a mixture of 75% anatase and 25% rutile.

In order to improve the service life of the filter membrane and reuse the photocatalyst, after the photocatalytic reaction is over, the backwash system is connected from the water collection pipe for backwashing, and the photocatalyst on the filter membrane is flushed into the reaction zone; The frequency is set to 1/7 to 1/10, preferably 1/9; the backwashing frequency refers to the ratio of the backwashing time to the time that the reactor operates for wastewater treatment.

Working principle: The working principle of the present invention is: open the upper cover of the mixing area, put the photocatalyst into the mixing area of the reactor, then open the water inlet of the water inlet area, and inject waste water containing organic pollutants into the water inlet area, so that the waste water It flows into the mixing zone through the water inlet hole at the bottom of the mixing zone. Since the bottom of the mixing zone is a conical shape that protrudes to the lower side of the mixing zone, a circulating flow of wastewater flowing up and down can be formed in the mixing zone, which helps the wastewater and the photocatalyst to mix evenly, reduces hydraulic loss, and makes the stirring process more adequate. Water was injected to about 5 cm below the upper end of the side wall of the mixing zone, the mechanical stirring device was turned on, and vigorous stirring was carried out for about 3 hours, so that the catalyst was evenly dispersed in the wastewater to form a catalyst suspension. Pull up the side wall of the mixing zone, so that the mixture of wastewater and photocatalyst enters the reaction zone, turn on the UV lamp, the photocatalyst catalyzes the reaction of organic pollutants in the wastewater, and at the same time turn on the cooling coil switch to reduce the temperature of the reaction zone and improve the reaction efficiency. Then, the waste water flows from the reaction zone to the water outlet zone through the side wall of the reaction zone, and the photocatalyst in the waste water is separated from the waste water by the filter membrane. After reacting for a period of time, the organic matter concentration in the treated wastewater was detected by sampling from the water collection pipe of the effluent area, and the treatment effect was qualified for three consecutive times, indicating that the reaction inside the reactor had reached stability. Then, the water collecting pipe is connected to the backwashing system to carry out backwashing, and the photocatalyst is flushed into the organic wastewater in the reaction zone to continue to function.

Beneficial effects: the technical scheme of the present invention has the following beneficial effects:

1. In the integrated mechanical photocatalytic membrane separation and coupling reactor of the present invention, the side wall of the reaction zone is composed of a support plate and a filter membrane wrapped on the outside of the support plate, and a water outlet area is surrounded on the outside of the side wall of the reaction zone. The separation of wastewater and photocatalyst after photocatalytic treatment can be realized effectively; when backwashing, the water collection pipe in the effluent area is directly connected to the backwashing system, so that the photocatalyst on the filter membrane enters the wastewater in the reaction area and continues to play a catalytic role and separation effect. High efficiency, high photocatalyst use efficiency; stirring and solid-liquid separation operations are all reacted in one reactor, no additional equipment is required, easy to carry, easy to operate, and low production cost, making the backwashing operation more convenient.

2. The integrated mechanical photocatalytic membrane separation and coupling reactor of the present invention can be designed to be fully automated, and can be operated unattended for a long time or remotely monitored through a new wireless communication system; the continuous operation of the reactor of the present invention to treat wastewater is It operates without the waste stream requiring further treatment (ie, no new waste enters the reactor), thereby allowing almost complete recovery of clean water; the reactor does not require chemical additives or other oxidants (eg, Cl ₂ , O ₃ , H ₂ O ₂ ), with a high degree of integration, especially suitable as a laboratory pilot plant, and compared with conventional water treatment processes, this reactor has relatively low energy consumption, which can achieve cost-effective and Environmentally friendly water purification technology.

Instruction drawings

Fig. 1 is the front view of the reactor of the present invention;

Figure 2 is a top view of the reactor of the present invention.

Detailed ways

Example 1

FIG. 1 is a view of the integrated mechanical photocatalytic membrane separation and coupling reactor of the present invention, and FIG. 2 is a top view of the integrated mechanical photocatalytic membrane separation and coupling reactor of the present invention. As shown in Figures 1 and 2, the integrated mechanical photocatalytic membrane separation and coupling reactor is provided with a water inlet zone 1, a mixing zone 2, a reaction zone 3 and a water outlet zone 4. The mixing zone 2 and the reaction zone 3 are respectively columnar containers, and the lower ends of the two side walls are flush, and the relative positions of the mixing zone 2, the reaction zone 3 and the water outlet zone 4 are concentric sleeves that are arranged in turn from the inside to the outside. The water inlet zone 1 is a tubular structure lying under the mixing zone 2 , the reaction zone 3 and the water outlet zone 4 .

The water inlet area 1 is provided with a water inlet 5; the mixing area 2 includes a mixing area side wall 6 and a mixing area bottom 7, the mixing area side wall 6 can move up and down relative to the mixing area bottom 7, and the mixing area 2 is provided with a mechanical stirrer 8, The bottom 7 of the mixing zone is close to the upper end of the water inlet zone 1, and is in the form of a conical structure protruding to the lower side of the mixing zone. The angle is about 30 degrees), the bottom 7 of the mixing zone is evenly distributed with a plurality of water inlet holes, the mixing zone 2 communicates with the water inlet zone 1 through the water inlet holes at the bottom 7 of the mixing zone, and the tip of the bottom 7 of the mixing zone is connected to the bottom of the water inlet zone. 13 Contacts. The setting of the inclination angle of the bottom of the mixing zone 2 can form a circulating flow of wastewater flowing up and down in the mixing zone, so that the wastewater and the catalyst are mixed evenly, reducing hydraulic loss and making the stirring process more sufficient. The lower part of the mixing zone 2 is surrounded by the reaction zone 3, the upper part extends out of the upper end of the reaction zone 3, and the mixing zone 2 is sealed and isolated from the reaction zone 3 by the side wall 6 of the mixing zone.

Reaction zone 3 includes reaction zone side wall 9 and reaction zone upper end 17, reaction zone upper end 17 seals the reaction zone, reaction zone 3 is provided with four 39W ultraviolet lamps 11 in parallel around mixing zone 2, and the wavelength of the light emitted by ultraviolet lamps 11 is 253.7 nm, each ultraviolet lamp 11 is respectively provided with a quartz protective sleeve, the ultraviolet lamp 11 is immersed in the reaction chamber of the reaction zone 3, and a cooling coil 14 is respectively coiled around the quartz protective sleeve, and the cooling coil 14 is connected from the reactor. After the bottom enters, the outer wall of the quartz protective sleeve outside the ultraviolet lamp 11 is coiled from bottom to top. The side walls 6 of the mixing zone can move up and down relative to the bottom 7 of the mixing zone. Since the volume of the mixing zone 2 is relatively small relative to the reaction zone 3, after the mixing is complete, when the side wall 6 of the mixing zone 2 is opened, the mixed liquid enters the reaction zone 3, and the water surface will inevitably drop. 2 is the same height, which will inevitably lead to a large part of the upper space that cannot be used and wasted. Therefore, the side wall 6 of the mixing zone is higher than the side wall 9 of the reaction zone to ensure that the space is more fully utilized after the side wall 6 of the mixing zone is pulled up.

The water outlet area 4 is arranged around the reaction area 3 , and the water outlet area 4 is provided with a water collecting pipe 12 parallel to the water inlet area 1 at the lower end of the side wall of the water outlet area 4 . The side wall 9 of the reaction zone is composed of a support plate 15 and a filter membrane 10 arranged close to the support plate 15. The filter membrane 10 is in the form of a plate filter membrane with a pore size of 0.03 microns. The support plate 15 is distributed with a plurality of permeable holes 16. 10. The pore size is 0.03 microns, and the reaction zone 3 is communicated with the water outlet zone 4 through the filter membrane 10 on the side wall 9 of the reaction zone.

During wastewater treatment, the upper cover of the mixing zone 2 is opened, and the photocatalyst is put into the mixing zone 2 of the reactor. The photocatalyst is a mixture composed of 75% anatase and 25% rutile. Then, the water inlet 5 of the water inlet area 1 is opened, and waste water containing trace organic pollutants is injected into the water inlet area 1, so that the waste water flows into the mixing area 2 through the water inlet hole at the bottom 7 of the mixing area. Since the bottom 7 of the mixing zone is a conical structure protruding toward the lower side of the mixing zone, a circulating flow of wastewater flowing up and down can be formed in the mixing zone 2, so that the stirring process is more sufficient. Water was injected to about 5cm below the upper end of the side wall 6 of the mixing zone, the mechanical stirring device 8 was turned on, and vigorously stirred for about 3 hours, so that the photocatalyst was uniformly dispersed in the waste water to form a catalyst suspension. Turn on the ultraviolet lamp 11, and pull up the side wall 6 of the mixing zone, so that the mixture suspension of the waste water and the photocatalyst enters the reaction zone, and the photocatalyst catalyzes the reaction of the organic pollutants in the waste water. The pipe 14 is used to lower the temperature of the reaction zone and improve the reaction efficiency. Next, the waste water flows from the reaction zone 3 to the water outlet zone 4 through the side wall 9 of the reaction zone, and the photocatalyst in the waste water is separated from the waste water by the filter membrane 10 . After reacting for a period of time, samples were taken from the outlet of the water collecting pipe 12 of the water outlet area 4 to detect the concentration of organic matter in the treated wastewater, and the treatment effect was qualified for three consecutive times, indicating that the reaction inside the reactor had reached stability. Then, the water collecting pipe 12 is connected to the backwashing system for backwashing, and the photocatalyst on the filter membrane 10 is flushed into the organic waste water in the reaction zone 3, and continues to play a role to realize the reuse of the photocatalyst. The backwash frequency was 1/9 (ie, the ratio of the reactor operation time for wastewater treatment to the backwash time was 9:1).

Example 2

The coking wastewater was treated with the integrated mechanical photocatalytic membrane separation and coupling reactor of Example 1. The initial COD value of the coking wastewater was 163.5 mg/L, and the TOC value was 12 mg/L. The treatment conditions were as follows:

Processing time: 60min;

Photocatalyst dosage: 2.5g/L;

The COD value in the treated wastewater is 70.3mg/L, and the TOC value is 2.8mg/L;

In addition, a common photocatalytic process device was used to treat coking wastewater. The initial COD value of the coking wastewater was 163.5 mg/L, the TOC value was 12 mg/L, and the experimental conditions (treatment time and photocatalyst dosage) were exactly the same. TOC value 3.9mg/L.

Example 3

Use the integrated mechanical photocatalytic membrane separation coupling reactor of Example 1 to treat commercial humic acid to prepare water to be treated, with a COD value of 89.8 mg/L and a TOC value of 8.7 mg/L, and treated under the following conditions:

Processing time: 40min;

Photocatalyst dosage: 1.5mg/L;

After treatment, the COD value was 38.6 mg/L, and the TOC value was 1.6 mg/L;

In addition, the commercial humic acid was used to prepare the water to be treated by ordinary photocatalytic process equipment. The COD value was 89.8mg/L, the TOC value was 8.7mg/L, and the experimental conditions (treatment time and photocatalyst dosage) were exactly the same, and the COD value after treatment was 49.1mg. /L, TOC value 2.9mg/L.

Example 4

Take a slightly polluted surface water, turbidity 12-15, TOC value 5.8mg/L, permanganate index 3.6mg/L, using the integrated mechanical photocatalytic membrane separation coupling reactor of Example 1 under the following conditions To process:

Processing time: 30min;

Photocatalyst dosage: 1mg/L

After treatment, the turbidity is 0, the TOC value is 0.9mg/L, and the permanganate index is 1.1mg/L;

In addition, the micro-polluted surface water was treated with a common photocatalytic process device. The experimental conditions (treatment time and photocatalyst dosage) were completely consistent. After treatment, the turbidity was 0, the TOC value was 1.8 mg/L, and the permanganate index was 2.3 mg/L.

Claims (4)

1. An integrated mechanical photocatalytic membrane separation and coupling reactor, characterized in that the reactor comprises a water inlet zone (1), a mixing zone (2), a reaction zone (3) and a water outlet zone (4); The water zone (1) is provided with a water inlet (5); the mixing zone (2) at least includes a side wall (6) of the mixing zone and a bottom (7) of the mixing zone, and the side wall (6) of the mixing zone may be opposite to the bottom ( 7) Moving up and down, a mechanical agitator (8) is provided in the mixing zone (2), the mixing zone (2) is communicated with the water inlet zone (1) through the bottom (7) of the mixing zone, and the The mixing zone (2) is sealed and isolated from the reaction zone (3) by the mixing zone side wall (6); the reaction zone (3) at least surrounds the lower part of the mixing zone side wall (6), and the reaction zone (3) at least includes The side wall (9) of the reaction zone, a filter membrane (10) is arranged on the side wall (9) of the reaction zone, and an ultraviolet lamp (11) is arranged in the reaction zone (3); The reaction zone (3) is separated from the water outlet zone (4), the water outlet zone (4) is provided with a water collecting pipe (12), and the bottom (7) of the mixing zone is a cone protruding toward the lower side of the mixing zone (2). The bottom of the mixing zone (7) is inclined at an angle of 25 to 35° relative to the bottom (13) of the water inlet zone, and the lower end of the bottom (7) of the mixing zone is connected to the water inlet. The bottom of the zone (13) is in contact, the reaction zone (3) is provided with a plurality of ultraviolet lamps (11) arranged in parallel around the mixing zone (2), and cooling coils are respectively coiled around the ultraviolet lamps (11). (14), the side wall (9) of the reaction zone includes a support plate (15) and a filter membrane (10) disposed close to the support plate (15), and a plurality of water permeable membranes are distributed on the support plate (15). Pores (16), the filtration membrane (10) has a pore size of 0.01-0.03 microns. 2 . The method for treating wastewater using the integrated mechanical photocatalytic membrane separation and coupling reactor according to claim 1 , wherein the method comprises: adding a photocatalyst to the mixing area through the top of the mixing zone ( 2 ). 3 . In the zone (2), the waste water is injected into the reactor from the water inlet (5), so that the waste water enters the mixing zone (2) through the bottom (7) of the mixing zone (2), and the mechanical agitator (8) is turned on. Mix the waste water and the photocatalyst evenly, turn on the ultraviolet lamp (11), and pull up the side wall (6) of the mixing zone, so that the mixture of the waste water and the photocatalyst enters the reaction zone (3) to carry out the photocatalytic reaction . 3. The method according to claim 2, characterized in that, after the photocatalytic reaction is completed, the water collecting pipe (12) is connected to a backwashing system for backwashing, and the photocatalyst on the filter membrane (10) is removed. Flush into the reaction zone (3) for reuse. 4 . The method according to claim 2 , wherein the backwashing frequency is 1/7~1/10, and the backwashing frequency refers to the ratio of the backwashing time to the time during which the reactor is operated for wastewater treatment. 5 .

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