Electrochemical air purification membrane structure, purification module, purifier and purification method
Technical Field
The invention belongs to the technical field of indoor air purification, and particularly relates to an electrochemical air purification membrane structure, a purification module, a purifier and a purification method.
Background
Air pollution has become a significant problem threatening human health. On one hand, various industrial pollution sources are numerous, and on the other hand, the indoor building and decorative materials continuously release toxic and harmful gases; although the whole atmospheric environment treatment can be finished in a short time, the small-space atmospheric environment treatment is easy to realize and takes effect quickly. According to statistics, modern people spend 80% -90% of the time indoors, so that the research and development of efficient and safe indoor air purifiers is an urgent need for improving the quality of life of people.
The existing air purification technologies capable of eliminating gas pollution are of the following types: 1. the photocatalysis technology is that under the irradiation of ultraviolet light, the semiconductor makes the putty to be processed in the valence band undergo the photo-electric excitation and jump to the conduction band, so as to form photo-generated electrons and photo-generated holes, and the photo-generated electrons and the photo-generated holes are mixed with the moisture and oxygen in the airThe gas reacts to generate a plurality of active groups, and organic pollutants and bacteria in the air are oxidized by the active groups; but the oxidation process may not be complete, and the intermediate product is easy to cause catalyst deactivation; 2. chemical catalytic oxidation, similar to photocatalysis, uses oxygen in air as an oxidant to oxidize organic substances, but it also suffers from deactivation problems and SO in air2The poisoning effect on the noble metal catalyst is very serious; 3. the plasma technology is that a strong electric field is used to generate plasma, high-energy electrons, free radicals and the like collide with pollutants to dissociate and oxidize the pollutants, but reaction byproducts contain ozone and nitrogen oxides, so that secondary pollution is brought. Meanwhile, no matter which purification technology is adopted, SO in the air cannot be effectively purified2。
Therefore, it is necessary to develop a more efficient and safe indoor air purification structure.
Disclosure of Invention
In view of the drawbacks of the prior art, the present invention aims to provide an electrochemical air purification membrane structure capable of improving purification efficiency and safety.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a solid electrolyte membrane for conducting protons or hydroxide ions in an electrochemical reaction;
and a pair of solid electrodes respectively disposed on opposite surfaces of the solid electrolyte membrane for oxidatively decomposing contaminants in air in contact with the surfaces thereof under a voltage applied thereto;
wherein the solid electrolyte membrane is an acid electrolyte membrane or an alkaline electrolyte membrane.
Based on the above-mentioned solution, it is further preferred that,
the acid electrolyte membrane comprises any one of a perfluorosulfonic acid membrane, a meta-fluorosulfonic acid membrane and a sulfonated hydrocarbon membrane; the alkaline electrolyte membrane includes, but is not limited to, any one of quaternary ammonium anion exchange membranes or quaternary phosphonium anion exchange membranes.
Based on the above-mentioned solution, it is further preferred that,
the stereoscopic electrode includes at least:
the porous conductive diffusion layer is used as a support layer of the three-dimensional electrode;
a catalyst distributed on the porous conductive diffusion layer;
and a binder.
Based on the above-mentioned solution, it is further preferred that,
the porous conductive diffusion layer includes but is not limited to any one of carbon cloth, carbon felt, copper foam, nickel foam and stainless steel foam.
Based on the above-mentioned solution, it is further preferred that,
the catalyst is a carbon-supported catalyst, and the active components of the catalyst include but are not limited to any one or the combination of more than two of platinum, palladium, ruthenium, nickel, chromium, cobalt, copper, tungsten, iron, cerium and molybdenum; the carbon carrier includes but is not limited to any one of carbon powder, carbon nano-tube and carbon aerosol.
Based on the above-mentioned solution, it is further preferred that,
the binder is selected according to the selected type of the solid electrolyte membrane; that is, if the solid electrolyte membrane is an acid electrolyte membrane, the binder is selected from a cation exchange resin capable of conducting H + or a combination of a cation exchange resin capable of conducting H + and a nonionic polymer; that is, if the solid electrolyte membrane is an alkaline electrolyte membrane, the binder is selected from an anion exchange resin capable of conducting OH "or a combination of an anion exchange resin capable of conducting OH" and a nonionic polymer.
Based on the above-mentioned solution, it is further preferred that,
the cation exchange resin comprises but is not limited to one or the combination of more than two of perfluorosulfonic acid resin, meta-fluorosulfonic acid resin and sulfonated hydrocarbon polymer resin; the anion exchange resin comprises but is not limited to one or the combination of more than two of quaternary ammonia resin or quaternary phosphorus polymer resin; the non-ionic polymer includes but is not limited to one or the combination of more than two of PTFE, PVDF and PBI.
Another object of the present invention is to provide a purification module based on the electrochemical air purification membrane structure of any of the above aspects, which comprises a plurality of the electrochemical air purification membrane structures.
Another object of the present invention is to provide a purifier based on the above purification module, which includes at least one of the purification modules.
Another object of the present invention is to provide a method for purifying an electrochemical air purification membrane structure based on any of the above aspects, which comprises the following steps:
s1, enabling air to flow through the three-dimensional electrode of the electrochemical air purification membrane structure;
and S2, applying voltage to the stereo electrodes to oxidize and decompose pollutants in the air, which are in contact with the surfaces of the stereo electrodes.
Compared with the prior art, the invention has the beneficial effects that:
the electrochemical air purification membrane structure can improve the purification efficiency of VOC (volatile organic compounds) and simultaneously eliminate SO in the air2And secondary pollution is prevented, and the purification safety is further improved.
Drawings
FIG. 1 is a schematic diagram of a membrane electrode structure according to the present invention;
FIG. 2 is a second schematic diagram of a structure corresponding to the membrane electrode structure of the present invention;
FIG. 3 is a schematic view of a structure corresponding to the voltage-applied membrane electrode structure according to the present invention;
FIG. 4 is a schematic illustration of a structure corresponding to the purification module of the present invention;
fig. 5 is a schematic diagram of the applied voltage.
In the figure: 101. a first three-dimensional electrode 102, a solid electrolyte membrane 103, a second three-dimensional electrode 104, a catalyst 105, an adhesive 111, a first applied voltage point 112, a second applied voltage point 201, and a purification unit component.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As described above, in view of the problems that the existing air purification technologies cannot further prevent the generation of secondary pollution while ensuring the purification efficiency, the present invention provides an electrochemical air purification membrane structure, as shown in fig. 1-2, comprising:
a solid electrolyte membrane for conducting protons or hydroxide ions in an electrochemical reaction;
and a pair of solid electrodes respectively disposed on opposite surfaces of the solid electrolyte membrane for oxidatively decomposing contaminants in air in contact with the surfaces thereof under a voltage applied thereto;
wherein the solid electrolyte membrane is an acidic electrolyte membrane conducting H + or an alkaline electrolyte membrane conducting OH-.
Based on the scheme, in a further preferred example 1, the acidic electrolyte membrane includes, but is not limited to, any one of a perfluorosulfonic acid membrane, a meta-fluorosulfonic acid membrane and a sulfonated hydrocarbon membrane; the alkaline electrolyte membrane includes, but is not limited to, any one of quaternary ammonium anion exchange membranes or quaternary phosphonium anion exchange membranes.
Based on the above preferred embodiment 1, and further preferred embodiment 2, the three-dimensional electrode includes at least:
the porous conductive diffusion layer is used as a support layer of the three-dimensional electrode;
a catalyst distributed on the porous conductive diffusion layer;
and a binder; wherein, the porous conductive diffusion layer comprises any one of but not limited to carbon cloth, carbon felt, copper foam, nickel foam and stainless steel foam; the catalyst is a carbon-supported catalyst, and the active component of the catalyst comprises but is not limited to any one or more alloy combinations of platinum, palladium, ruthenium, nickel, chromium, cobalt, copper, tungsten, iron, cerium and molybdenum; the carbon carrier comprises any one of carbon powder, carbon nano tube and carbon aerosol; the binder is selected according to the selected type of the solid electrolyte membrane; that is, if the solid electrolyte membrane is an acid electrolyte membrane, the binder is selected from a cation exchange resin capable of conducting H + or a combination of a cation exchange resin capable of conducting H + and a nonionic polymer; that is, if the solid electrolyte membrane is an alkaline electrolyte membrane, the binder is selected from an anion exchange resin capable of conducting OH < - > or a combination of an anion exchange resin capable of conducting OH < - > and a nonionic polymer;
based on the above preferred embodiment 2, the further preferred embodiment 3,
the cation exchange resin comprises but is not limited to one or the combination of more than two of perfluorosulfonic acid resin, meta-fluorosulfonic acid resin and sulfonated hydrocarbon polymer resin; the anion exchange resin comprises but is not limited to one or the combination of more than two of quaternary ammonia resin or quaternary phosphorus polymer resin; the non-ionic polymer includes but is not limited to one or the combination of more than two of PTFE, PVDF and PBI.
Based on the above preferred embodiment 2, the further preferred embodiment 4,
as shown in fig. 3, the three-dimensional electrode may be divided into a first three-dimensional electrode and a second three-dimensional electrode, a voltage is applied to each side of the two three-dimensional electrodes away from the solid electrolyte membrane through a metal mesh, and the voltage applied to the first and second three-dimensional electrodes by the air flow in use is 0.8 to 1.5V; the application method is alternate application with time interval of 0.5-10 min.
Another object of the present invention is to provide a purification module based on the electrochemical air purification membrane structure of any of the above aspects, which comprises a plurality of the electrochemical air purification membrane structures.
Another object of the present invention is to provide a purifier based on the above purification module, which includes at least one of the purification modules.
Another object of the present invention is to provide a method for purifying an electrochemical air purification membrane structure based on any of the above aspects, which comprises the following steps:
s1, enabling air to flow through the three-dimensional electrode of the electrochemical air purification membrane structure;
and S2, applying voltage to the stereo electrodes to oxidize and decompose pollutants in the air, which are in contact with the surfaces of the stereo electrodes.
Wherein, a stream of air can flow through a plurality of electrochemical air purification membrane structures or all electrochemical air purification membrane structures.
The above scheme is illustrated below by the practical experimental examples:
example 1: in this embodiment, the first stereo electrode and the second stereo electrode are the same, and the stereo electrode preparation process: the supporting layer used by the three-dimensional electrode is a carbon felt, the thickness of the supporting layer is about 3mm, and the size of the supporting layer is 4cm multiplied by 15 cm; coated thereon with 1mg/cm2The mixture of carbon powder and Nafion, wherein the mass fraction of Nafion is 15%; then dipping the carbon felt into the catalyst slurry for 2min, taking out the carbon felt, drying the carbon felt in a vacuum oven, and repeating the steps for 5 times to finally form 2 with the catalyst loading capacity of 0.2mgPt/cm on the three-dimensional electrode; wherein the slurry consists of Pt/C (20 wt. JM company), Nafion solution with the concentration of 5% and ethanol, and the mass ratio of Nafion, Pt/C and ethanol is 1: 4: 40.
the prepared three-dimensional electrode is respectively arranged on one side of a cation exchange membrane Nafion-112, and is hot-pressed for one minute at the temperature of 120 ℃ and under the pressure of 4000 pounds to form an integrated membrane electrode structure.
Example 2: in this embodiment, the first stereo electrode and the second stereo electrode are the same, and the stereo electrode preparation process: the supporting layer used by the three-dimensional electrode is a carbon felt, the thickness is about 3mm, and the size is 4cm multiplied by 15 cm; carbon powder and PTFE mixture of 1mg/cm2 are coated on the surface, wherein the mass fraction of PTFE is 30%; then soaking the three-dimensional electrode in the catalyst slurry for 2min, taking out the three-dimensional electrode, drying the three-dimensional electrode in a vacuum oven, and repeating the steps for 5 times to finally form 2 with the catalyst loading capacity of 0.2mgPt/cm on the three-dimensional electrode; wherein the slurry consists of Pt/C (20 wt. JM company), PTFE solution with the concentration of 5 percent and ethanol, and the mass ratio of the PTFE to the Pt/C to the ethanol is 1.6: 4: 40.
the prepared three-dimensional electrode is respectively arranged on one side of an anion exchange membrane FAA-3-PK-130 membrane, and is hot-pressed for one minute at the temperature of 60 ℃ and under the pressure of 4000 pounds to prepare an integrated membrane electrode structure.
Example 3: stainless steel metal nets are placed on two sides of the integrated membrane electrode structure prepared in the embodiment 1 to serve as components, the six components are placed side by side to form a purification module, and porous metal current collectors are tightly attached to two sides of a membrane electrode unit and are shown in fig. 4; then, plastic end plates are covered on two sides, air circulation flow channels in parallel grooves are formed on the end plates, and the two end plates are fastened by plastic nails. When the membrane electrode assembly works, a fan is adopted to force air convection, the air circulation direction is shown in figure 4, the square wave voltage applied to the two sides of the membrane electrode through the stainless steel mesh is 0.8V, the time interval is 2min, and the voltage waveform is shown in figure 5. Experiments prove that: with formaldehyde (3mg/m3) and SO2(2mg/m3) as a simulated pollutant, the formaldehyde residue is less than 0.5 percent and SO is contained in a closed space of 1m3 after the operation for 30min2Less than 1% of residue and outstanding purification effect.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.