CN106196321A - A kind of novel photocatalysis air purifier and the method purifying air - Google Patents

Abstract

The invention discloses a novel photocatalytic air purifier, which comprises an air purifier body. The air purifier body includes a shell, and the shell is provided with an air inlet and an air outlet. The inner edge of the shell is In the direction of air flow, there are primary filter screen, high-performance nanofiber filter screen, visible LED light source, visible light responsive photocatalyst filter screen, circulation fan, and humidification device, and the air inlet is set on the side wall of the housing. , the air outlet is arranged on the top of the casing, the humidifying device is arranged under the air outlet, and the inside of the casing is also provided with an electrical circuit and an external power cord. The purifier can not only efficiently filter and intercept particulate pollutants and virus bodies of different sizes in the air, effectively degrade and mineralize different types of VOCs in the air, but also realize the adjustment of the air humidity after purification.

Description

Novel photocatalytic air purifier and method for purifying air

technical field

The invention relates to the technical field of air purification, and relates to a novel photocatalytic air purifier and a method for purifying air.

Background technique

With economic development and social progress, the problem of environmental pollution is becoming more and more serious. Volatile organic compounds (Volatileorganic compounds, VOCs) are the main pollutants in the atmosphere, part of which comes from outdoors, mainly industrial waste gas, motor vehicle exhaust, photochemical smog, etc.; the other part comes from indoors, decoration, decoration materials such as paint and Its solvents, wood preservatives, paints, plywood, etc. can release various volatile organic substances such as toluene and formaldehyde at room temperature. Due to the poor air mobility in the indoor environment, the accumulated pollutants have caused serious harm to the human body through human breathing and skin. Taking formaldehyde as an example, if the human body is exposed to formaldehyde with a concentration greater than 0.1 mg/ ^m3 for a long time, it will cause dizziness, audiovisual blockage, and in severe cases, it will cause damage to the respiratory system, cardiovascular and cerebrovascular, etc. The mixed existence of various VOCs and the chemical interaction with each other will also increase the harm intensity. Therefore, improving indoor air quality through purification technology is of great significance to people's health.

The technologies used for VOCs purification mainly include adsorption filtration technology, condensation technology, combustion technology, membrane separation technology, biodegradation technology, combustion technology, plasma purification technology and photocatalytic technology. Photocatalytic technology is the use of photocatalysts under the light greater than or equal to its forbidden band width to generate redox effects of electrons, holes and pollutants to completely decompose and mineralize harmful pollutants in the air under normal temperature and pressure conditions. Harmless inorganic small molecules (such as CO ₂ , H ₂ O, etc.), with low energy consumption and simple operation, are an effective way to degrade indoor VOCs, and have broad prospects in air pollution control. Combining photocatalytic technology with adsorption filtration technology to construct photocatalytic air purification technology (purifier) has gained widespread attention.

However, so far, there are still many problems in photocatalytic air purification technology: (1) The adsorption filtration technology used is mainly realized by activated carbon filter screen or HEPA filter screen, but these two filter screens have their own technical defects. The removal rate of the activated carbon filter is low and requires regular evolution and activation. It does not reduce the total amount of VOCs. Once it reaches saturated adsorption, it will become a pollution source from the air purifier; the effective pore size of the HEPA filter is above 300 nanometers, only It can filter out particles with a particle size of more than 300 nanometers in the air, but cannot filter out particles with a particle size of less than 300 nanometers, such as virus bodies. Although it has been reported that photocatalytic technology can be used for the degradation of living organisms such as virions, the effect is very poor; (2) The photocatalytic technology used is mainly realized by _TiO2 photocatalyst plus ultraviolet light source. Since the bandgap of TiO ₂ is 3-3.2 eV, the photoresponse range is in the ultraviolet region, the utilization rate of irradiation is low, and the recombination probability of photogenerated carriers of TiO ₂ is high, resulting in a great limitation in the efficiency of photocatalytic degradation. . At the same time, the ultraviolet mercury lamp (9-20 W) used as the ultraviolet excitation light source will produce a small amount of ozone when it interacts with oxygen in the air for a long time, which has potential safety hazards. In addition, the waste mercury lamp is a pollution source, which is safe and pollution-free to use 1. Long-life light sources are the inevitable trend of the photocatalytic air purifier industry in the future; (3) Due to the generally poor air quality, people spend more and more time in a closed indoor environment using air conditioning or heating to maintain proper indoor air quality. Humidity is sufficient and necessary to maintain human comfort and health, but existing photocatalytic air purification equipment usually cannot have the function of humidity adjustment at the same time, and additional equipment such as air humidifiers are required.

Contents of the invention

Aiming at the deficiencies of the above-mentioned existing equipment and technology, the present invention proposes a new type of photocatalytic air purifier, which integrates high-performance nanofiber filter, visible LED light source, visible light responsive photocatalyst filter and humidification device, to solve the problem of existing photocatalytic air purifier. The problem of poor purification effect of air purifiers.

The technical scheme adopted in the present invention is as follows:

A novel photocatalytic air cleaner, which includes an air cleaner body, the air cleaner body includes a housing (1), and the housing (1) is provided with an air inlet (8), an air outlet ( 9), characterized in that: the housing (1) is sequentially provided with a primary filter (3), a high-performance nanofiber filter (4), a visible LED light source (5), Visible light responsive photocatalyst filter (6), circulation fan (7), humidifier (2), the air inlet (8) is set on the side wall of the shell, and the air outlet (9) is set on the shell On the top of the housing, the humidifying device (2) is located below the air outlet (9), and the housing (1) is also provided with an electrical circuit and an external power cord.

The primary filter refers to a filter that can filter out PM10, dander and other large particle size pollutants, and can also prevent insects from entering the interior of the purifier and causing structural damage.

The high-performance nanofiber filter screen refers to a filter screen containing high-performance nanofibers, which can efficiently filter out PM2.5, bacteria, viruses, cooking fume and other pollutants with a particle size between 100 nanometers and 10 microns.

Preferably, the nanofiber refers to a one-dimensional material with a diameter of 1-200 nanometers and a length ranging from tens of micrometers to millimeters. The material can be polymer nanofibers, such as polyester, polylactic acid, polyurethane, polystyrene, polyacrylonitrile, polyvinyl alcohol, etc., or inorganic nanofibers, such as SiO ₂ , TiO ₂ , etc. If nanofibers are to have an antibacterial function, materials such as silver salts and copper salts can be added to nanofibers.

The visible LED light source refers to an LED light source with an emission wavelength between 380 nm and 780 nm. It can be seen that the LED light source is not only energy-saving and environmentally friendly, but also harmless to humans and animals, and is suitable for use in various occasions.

The visible light-responsive photocatalyst filter screen refers to a filter screen containing a visible light-responsive photocatalyst, which can undergo a photocatalytic reaction under visible light, thereby realizing the degradation and mineralization of VOCs.

Preferably, the visible light-responsive photocatalyst can be either a metal or non-metal modified _TiO2 photocatalyst, or a new non- _TiO2 photocatalyst.

The visible LED light source is located above the visible light-responsive photocatalyst filter, and can irradiate the fluorescence emitted by the visible LED light source onto the visible light-responsive photocatalyst filter, thereby realizing efficient degradation and mineralization of the photocatalyst in the visible light-responsive photocatalyst filter under visible light VOCs.

The humidifying device refers to a device that can conveniently disassemble the humidifying module and independently control the switch. Under the action of ultrasound, it can generate water vapor to increase the humidity of the environment where the purifier is located.

An air inlet is provided on the left side of the housing, and an air outlet is provided above the housing. The polluted air enters the purifier from the air inlet, passes through the primary filter, the high-performance nanofiber filter and the visible light-responsive photocatalyst filter in turn, and is purified into clean air, and leaves the air outlet for purification together with the water vapor generated by the humidifier device.

In order to ensure that the purified clean air can be discharged from the purifier as soon as possible, the smooth circulation of indoor air during the purification process, and to prevent the water vapor generated by the humidifying device from polluting the filter screen in the purifier, a circulating fan is installed in the purifier. The circulation fan is located between the visible light responsive photocatalyst filter screen and the humidifying device in the purifier.

The housing and each unit module are fixed by flexible connections, such as screw connections or card connections, so as to facilitate disassembly, maintenance and replacement.

A method for purifying air by an air purifier according to claim 1, characterized in that: under the action of the circulating fan (7), the polluted air enters the interior of the purifier from the air inlet (8), and first passes through the primary filter (3) Perform primary filtration to filter out large particle pollutants such as PM10, dander, and insects in the air; the air after primary filtration enters the high-performance nanofiber filter (4) for secondary filtration to filter out the air Small particle pollutants such as PM2.5 and virions; the air after secondary filtration then enters the visible light response photocatalyst filter (5) for photocatalytic filtration to achieve effective degradation and mineralization of VOCs in the air; photocatalysis The degraded and mineralized clean air is finally mixed with the water vapor generated by the humidifier (2) and discharged out of the purifier to obtain purified air with suitable humidity.

Compared with the prior art, the advantages of the present invention are reflected in:

(1) Replace the HEPA filter with a high-performance nanofiber filter. Since the pore size of the high-performance nanofiber filter is smaller than that of the HEPA filter, it can not only filter PM2.5 and other particulate matter, but also intercept small particle-sized pollutants such as viruses and bacteria;

(2) Use visible light LED light source + visible light catalyst to replace ultraviolet light source + TiO ₂ photocatalyst. The use of high-efficiency visible light catalysts can improve the performance of catalysts in degrading VOCs. At the same time, visible LED light sources have the advantages of energy saving, environmental protection and harmlessness to humans and animals;

(3) Integrated humidification function. The humidity of the purified air can be adjusted independently, and maintaining an appropriate air humidity in the environment where the purifier is located is very necessary for maintaining human comfort and health.

In short, the new photocatalytic air purifier of the present invention can not only efficiently filter and intercept particulate pollutants and virus bodies of different sizes in the air, effectively degrade and mineralize different types of VOCs in the air, but also realize the adjustment of the humidity of the purified air . The purifier has a compact structure and is safe to use. It is suitable for air purification in various places such as hotels, buildings, office buildings, apartments, houses, and cars.

Description of drawings

Fig. 1 is the structural representation of the novel photocatalytic air purifier of embodiment 1;

Fig. 2 is the performance of visible light catalyst+LED light source degradation VOCs in embodiment 2;

FIG. 3 is an electron microscope picture of the high-performance nanofiber prepared in Example 3.

detailed description

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only to further illustrate the features and advantages of the present invention, rather than limiting the claims of the present invention.

Example 1

This example is used to understand the structure and working principle of the new photocatalytic air purifier.

A novel photocatalytic air cleaner, as shown in Figure 1, includes an air cleaner body, the air cleaner body includes a housing 1, the side wall of the housing 1 is provided with an air inlet 8, and the top is provided with an air outlet 9, Inside the shell 1 along the direction of air flow, there are primary filter 3, high-performance nanofiber filter 4, visible LED light source 5, visible light responsive photocatalyst filter 6, circulation fan 7, humidifier 2, humidifier 2 is located below the air outlet 9, and the housing 1 is also provided with an electrical circuit and an external power cord.

The specific work of the purifier: under the action of the circulating fan 7, the polluted air enters the purifier from the air inlet 8, and passes through the primary filter 3, the high-performance nanofiber filter 4 and the visible light-responsive photocatalyst filter 6 in sequence. Then it is discharged out of the purifier together with the water vapor generated by the humidifying device 2, so as to realize the cleaning of the polluted air and the adjustment of the ambient humidity. It can be seen that the new photocatalytic air purifier provided by this solution can not only effectively intercept various particulate pollutants in the air, efficiently degrade VOCs in the air, but also adjust the humidity of the ambient air.

The primary filter screen 3 refers to a filter screen that can fully filter large particle pollutants such as PM10, dander, and insects in the air, so as to reduce the damage of these pollutants to the purification module and the circulation fan 7 .

Preferably, the high-performance nanofiber filter 4 refers to a filter containing one-dimensional nanomaterials, which can efficiently intercept small particle size pollutants such as PM2.5 and virions. The one-dimensional material has a diameter of 1-200 nanometers and a length ranging from tens of microns to millimeters.

It can be understood that the high-performance nanofibers described in this embodiment can be polymer nanofibers, such as polyester, polylactic acid, polyurethane, polystyrene, polyacrylonitrile, polyvinyl alcohol, etc., or can be Inorganic nanofibers, such as SiO ₂ , TiO ₂ , etc. If nanofibers are to have an antibacterial function, materials such as silver salts and copper salts can be added to nanofibers.

Preferably, the visible LED light source refers to an LED light source with an emission wavelength between 380 nm and 780 nm.

Preferably, the visible light-responsive photocatalyst filter 6 refers to a filter containing a visible light-responsive photocatalyst, which can efficiently degrade and mineralize VOCs in polluted air under the excitation of the visible LED light source 5 .

It can be understood that the visible light-responsive photocatalyst described in this embodiment can be either a metal or non-metal modified TiO ₂ photocatalyst, or a new type of photocatalyst other than TiO ₂ .

Preferably, the humidifying device 2 refers to a device that can conveniently disassemble the humidifying module and independently control the switch, and can generate water vapor under the action of ultrasound to increase the humidity of the environment.

Preferably, the circulation fan 7 is located between the visible light-responsive photocatalyst filter 6 and the humidifier 2, which can not only ensure the circulation of air, but also prevent the reverse flow of water vapor from causing damage to the filter.

Preferably, the primary filter 3, the high-performance nanofiber filter 4, the visible LED light source 5, the visible light-responsive photocatalyst filter 6 and the humidifier 2 can be freely disassembled, maintained and replaced without causing damage to other components. impact, thereby ensuring the performance of the purifier and prolonging the life of the purifier.

Preferably, the internal electrical circuit system of the device can independently control the opening and closing of each unit module. Such a design can facilitate people to choose to temporarily turn off a certain function of the device during the working process of the purifier.

Example 2

This example is used to investigate the performance of the visible light-responsive photocatalyst filter screen for degrading VOCs under the excitation of a visible LED light source.

Weigh 0.1 g of Y ₂ O ₂ S photocatalyst (our previous work, a high-efficiency visible light catalyst and its preparation method, application number 201510692553.2), add it to 10 ml of absolute ethanol, and form a uniform suspension after ultrasonication for 30 minutes . Then, the suspension was dispersed into a glass filter core with a diameter of 6.5 cm to make a visible light-responsive photocatalyst filter.

Paste a visible LED light source (emission wavelength at 420 nm) on a DC fan to make an excitation light source.

The visible light-responsive photocatalyst filter and excitation light source were fixed in a custom-made quartz sleeve, and the distance between the visible LED light source and the visible light-responsive photocatalyst filter was 5 cm. The thimble was then placed in a 5 liter custom made quartz glass reaction chamber.

Formaldehyde was used as a model compound to evaluate the photocatalytic performance. Among many indoor VOCs, formaldehyde is one of the main pollutants. When people inhale a high concentration of formaldehyde in a short period of time, it can cause tearing, dizziness, headache, fatigue, blurred vision, etc. The conjunctiva and throat are obviously congested, and some patients have rough breath sounds or dry rales on auscultation. Severe cases may have persistent cough, hoarseness, chest pain, and dyspnea. Severe cases can cause systemic damage to nerves and organs. The human body concentration limit of formaldehyde is 0.08ppm.

Fill the reaction chamber with 4000 ppm formaldehyde gas, then turn on the LED light source and fan to start the photocatalytic reaction and start timing. At regular intervals, 500 microliters of gas was taken out from the reaction chamber using an airtight syringe, and then detected in a gas chromatograph to determine the concentration of formaldehyde in the gas.

As shown in Figure 2, as the reaction progressed, the concentration of formaldehyde in the reaction chamber gradually decreased. _CO formation was detected in the gas, indicating that formaldehyde was degraded and mineralized by photocatalysis. After 90 hours of photocatalytic reaction, the concentration of formaldehyde is less than 1% of the initial concentration, and the degradation rate exceeds 99%. The results show that the use of visible LED light source + visible light-responsive photocatalyst filter can not only efficiently degrade and mineralize VOCs, and realize the purification of polluted air, but also the performance of the visible light-responsive photocatalyst filter has not decayed after 90 hours of reaction. Show good photocatalytic stability.

Example 3

This example is used to investigate the structure of high-performance nanofibers.

Weigh 100 grams of nylon powder, add it to 400 grams of formic acid, stir for 60 minutes, and mix it evenly to obtain a nylon solution 1 with a concentration of 25 wt%.

Add 0.8 grams of Pingpingao O (that is, alkyl polyoxyethylene ether) into 100 grams of deionized water, stir for 45 minutes, and mix well to obtain Pingpingao O solution 2 with a concentration of 0.8 wt%.

0.05 g of sodium dodecylsulfonate was added to 100 g of deionized water, stirred for 30 minutes, and mixed uniformly to obtain a sodium dodecylsulfonate solution 3 with a concentration of 0.05 wt%.

Take 10 ml of Pingpingjia O solution 2 and 10 ml of sodium dodecylsulfonate solution 3, add it to nylon solution 1, and prepare nylon nanofibers by using an air-flow electrospinning machine.

Figure 3 is an electron microscope picture of the prepared nylon nanofibers. It can be seen from the picture that the nylon nanofibers we prepared have a diameter of about 100 nanometers and a length ranging from tens of microns to millimeters. Compared with ordinary fibers, the nanofibers are not only more than an order of magnitude finer in particle size, but also have stronger adsorption than ordinary fibers, and can more effectively capture particles passing through the surface. The high-performance nanofiber filter made of this nanofiber has a pore size between 50 nanometers and 100 nanometers, which can not only efficiently intercept PM2.5, virus bodies and other pollutants, but also has low air resistance and high dust holding rate.

The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to these embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A novel photocatalytic air cleaner, which comprises an air cleaner body, and the air cleaner body includes a housing (1), and the housing (1) is provided with an air inlet (8), an outlet The tuyere (9) is characterized in that: the housing (1) is sequentially provided with a primary filter (3), a high-performance nanofiber filter (4), and a visible LED light source (5) along the direction of air flow. ), visible light responsive photocatalyst filter (6), circulation fan (7), humidifier (2), the air inlet (8) is set on the side wall of the casing, and the air outlet (9) is set On the top of the housing, the humidifying device (2) is arranged below the air outlet (9), and the housing (1) is also provided with an electrical circuit and an external power cord. 2. The new photocatalytic air purifier according to claim 1, characterized in that: the primary filter (3), high-performance nanofiber filter (4), visible LED light source (5), visible light response light The catalyst filter screen (6), the humidifying device (2) and the casing (1) are all fixed by flexible connections. 3. The new photocatalytic air purifier according to claim 1, characterized in that, the primary filter refers to a filter that can filter out PM10, dander, insects and large particle pollutants with larger particle sizes . 4. The new photocatalytic air purifier according to claim 1, characterized in that, the high-performance nanofiber filter screen refers to a filter screen containing high-performance nanofibers, which can efficiently intercept PM2.5, virus bodies and other Small particle pollutants. 5. The new photocatalytic air purifier according to claim 3, characterized in that: the high-performance nanofiber refers to a one-dimensional material with a diameter of 1-200 nanometers and a length ranging from tens of microns to several millimeters, The one-dimensional material is selected from one of polymer nanofibers and inorganic nanofibers; the polymer nanofibers are selected from polyester, polylactic acid, polyurethane, polystyrene, polyacrylonitrile, polyvinyl alcohol One of. 6. The novel photocatalytic air purifier according to claim 1, characterized in that: said visible LED light source refers to an LED light source whose emission wavelength is between 380 nanometers and 780 nanometers. 7. The new photocatalytic air purifier according to claim 1, characterized in that: the visible light responsive photocatalyst refers to a photocatalyst capable of photocatalytic reaction under visible light to degrade and mineralize different types of VOCs. 8. The novel photocatalytic air cleaner according to claim 7, characterized in that: the photocatalyst can be a metal or nonmetal modified TiO ₂ photocatalyst. 9. The novel photocatalytic air cleaner according to claim 7, characterized in that: the photocatalyst can also be non-TiO ₂ novel photocatalysts. 10. A method for purifying air by an air purifier according to claim 1, characterized in that: under the action of the circulating fan (7), the polluted air enters the interior of the purifier from the air inlet (8), and first passes through the primary effect The filter screen (3) performs primary filtration to filter out large particle pollutants such as PM10, dander, and insects in the air; the air after the primary filtration enters the high-performance nanofiber filter screen (4) for secondary filtration to filter out Small particle pollutants such as PM2.5 and virions in the air; the air after secondary filtration then enters the visible light-responsive photocatalyst filter (5) for photocatalytic filtration to achieve effective degradation and mineralization of VOCs in the air; The clean air after photocatalytic degradation and mineralization is finally mixed with the water vapor generated by the humidifier (2) and discharged out of the purifier to obtain purified air with suitable humidity.