The present disclosure relates, generally, to the field of air purification module. More particularly, the present disclosure relates to an air purification module based on photocatalytic oxidation of chemical contaminants such as volatile organic compounds (VOCs), ozone, etc. and disintegration of microorganisms such as bacteria, viruses, fungi, spores, mycotoxins etc.
BACKGROUND OF INVENTION
[0002] Air pollution is one of the maj or factors contributing towards adverse health related issues across the world. While there is awareness towards ambient air pollution, the household air quality still gets neglected. Indoor air quality is as important as outdoor air quality since majority of the time is spent in the indoor conditions of school, colleges, offices, and residential buildings. In some of the regions the concentration of pollutants present in the indoor air may be significantly higher than outdoor air. As per Environmental Protection Agency (EPA), indoor air quality may be 3-5 times more polluted than outdoor air quality.
[0003] Indoor air pollution can cause severe health issues varying from short term headache, allergies, breathing discomfort, infections, etc. to chronic respiratory and heart diseases. Even short term discomfort can be very alarming if left unattended.
[0004] Indoor environment is exposed to significant amount of pollutants such as volatile organic compounds (VOCs), harmful gases, microbial pollutants, etc. by routine human activities and household products used inside the building. Emissions released in the outside environment during fuel combustion from automobiles, construction and mining activities, etc. are also responsible for increased level of pollutants inside the buildings.

[0005] Human activities such as smoking, domestic cooking, and burning of fuel like kerosene, gas, wood, etc. leads to release of harmful gases. Carbon monoxide, nitrogen dioxide, and sulphur dioxide are some of the harmful gases which are responsible for poor indoor air quality. Some of the common sources contributing towards the increased level of VOC's inside the building are furnishing products, decorating materials, cleaning agents, pesticides, etc. Consumer products such as cleaning agents, paints, varnishes, glues, pesticides, etc. are common sources of harmful halogenated and aromatic compounds like benzene, xylene, toluene, methylene chloride, and p-chlorobenzene inside the building. Fabric softeners, and room fresheners commonly used these days release a significant amount of terpenes. Other products related to cosmetics, and adhesives also contribute significantly towards increased concentrations of alcohol based volatile organic compounds. Emissions released from smoking are also responsible for the increased levels on polycyclic aromatic hydrocarbons, benzene, formaldehyde, etc. inside the building. Prolonged exposure to these VOCs may result in mild irritation and exposure to a high concentration may even result in acute lung injuries.
[0006] One of the dominant pollutants present in indoor conditions are particulate matter (PM). Long term exposure to particulate matter can impact cardiopulmonary functioning of human body. These pollutants constitute a mixture of gases, organic and inorganic compounds ranging with particle size small enough to interfere the human airways. Soot and smoke in the indoor condition majorly comprises of particulate matter ranging from very fine particles of less than 2.5 microns to coarse particles of more than 10 microns.
[0007] Indoor air contains a wide range of microbial contaminants such as bacteria, fungi, allergens, viruses, molds, etc. Humidity, dampness and air conditioning system enhance the moisture content in the indoor environment which leads to the growth of molds in the interior damp surfaces of the house. Similarly, humidifiers used in the rooms may generate a significant amount of aerosols in the indoor air. Dust mites,

animal dander, and plant pollen are few common sources of indoor allergen. Majority of transmission of airborne pollutants occur through pets and human beings. Bacteria and viruses found in the respiratory tract are often transmitted through talking, coughing or sneezing which may result in infectious diseases. Microorganisms can also be carried by animals, soil, plant debris and can sweep in from outdoor sources as well.
[0008] There are various technologies existing for controlling air pollutants, most commonly used are filter based technologies which aim at trapping the contaminants using an array of filters. However, their performance varies with environmental conditions such as humidity, concentrations of contaminants, etc. Although air filtration technology is widely used for preventing exposure to particulate matter, VOC's, and micro-organisms, the trapped particles are still hazardous if not treated subsequently. Air cleaning techniques such as electrostatic precipitator, carbon based filtration and High Efficiency Particulate Air Filtration may have a limitation of contaminants retainment in the system.
[0009] Some devices use germicidal ultraviolet radiations for disinfection of the micro-organisms present in the air. In many such ultraviolet light devices, treatment of air is attempted by allowing the air to move by natural or forced convection through the ultraviolet light spectrum produced by ultraviolet light sources, such as bulbs, lamps, LEDs, etc. By virtue of being entrained in the air, the microorganisms also pass through and come in contact with the ultraviolet radiations. These radiations penetrate the cell and interact with the genetic material, thus resulting in inactivation of the microorganisms. However, because the exposure time of the microorganisms to intense ultraviolet light is often too short in duration due to movement of the air, many of the microorganisms escape and survive without being hit by a sufficient number of photons.
[0010] Another air cleaning devices include plasma-based methods in which a high voltage (HV) discharge is used for the generation of reactive ions or radicals further responsible for the destruction of pollutants. Technologies such as ionization, and non-

thermal plasma decomposition, may generate ozone as a harmful by-product. Such devices may cause ozonolysis with various volatile organic compounds found in indoor environment (such as terpenes & terpenoids) and form hazardous compounds such as formaldehyde, 4-oxopentanal, etc.
[0011] In recent years, air purification technology based on photocatalytic oxidation has gained much attention. The process involves absorption of photons by a photocatalyst from UV radiations and formation of reactive oxygen species (ROS) such as hydroxyl radicals. These hydroxyl radicals, OH* are strong oxidizing agents, which oxidizes a vast range of organic molecules in a short span of time. Comparatively this technology offers more ecofriendly approach to purify air.
[0012] US7255831 B2 discloses a tungsten oxide/titanium dioxide photocatalyst for improving indoor air quality. A light source positioned between successive honeycombs activates the tungsten oxide/titanium dioxide photocatalytic coating on the surface of the open passages. The honeycombs and the light source are place in alternate in the air purification system. That is, ultraviolet lights are located between each of the honeycombs. Preferably, the light source is an ultraviolet light source which generates light having a wavelength in the range of 180 nm to 400 nm. When a contaminant present in the air is adsorbed onto the tungsten oxide/titanium dioxide photocatalyst coating, the hydroxyl radicals attack the contaminant, abstracting a hydrogen atom from the contaminant. In this method, the hydroxyl radical oxidizes the contaminants and produces water, carbon dioxide, and other substances. However, in honeycomb arrangement, there is no sufficient exposure of substrate to the ultraviolet light and most of the radiance may get wasted. Thus the system may be less efficient.
[0013] US20130171031A1 relates to an air filtration system and a method for making a photocatalytic oxidation substrate by powder coating a photocatalyst onto a metal substrate. Air filtration system comprising a particulate filter; a substrate powder coated, cured and impregnated with a photocatalyst, at least one UV light source for irradiating UV light on the substrate; and at least one reflector positioned adjacent the

at least one UV light source for reflecting UV light toward the substrate. This system comprising filter, thus all limitations associated with filter are linked with this system. Also aluminium mesh has been used as the substrate and the mesh might not ensure sufficient exposure.
[0014] US10010644B2A discloses a photocatalytic device which comprising Manganese dioxide and Titanium dioxide coated housing, an ultraviolet light source disposed therein, and a plurality of multi-metallic photocatalytic structures, such as hydrated multi-metallic catalyst substrates, is adapted to be deployed in conjunction with the exchange air intake of a mini-split system. The photocatalytic device has (a) Manganese dioxide and Titanium dioxide coated reflector(s) that is/are positioned to reflect ultraviolet light onto the photocatalytic structures. The photocatalytic device may have at least one carbon fibre and/or needle type ionizer disposed in the housing. The photocatalytic device may also have at least one sensor and may be wirelessly coupled to a computing device or controller. This device also lacks sufficient exposure to UV light, reflectors are required for directional exposure thus incorporating additional cost. Thus the system may not be very efficient.
[0015] US6409928B1A relates to a method and apparatus for mineralizing organic contaminants in water or air provides photochemical oxidation in a two-phase or three-phase boundary system formed in the pores of a Ti02 membrane in a photocatalytic reactor. In the three-phase system, gaseous (liquid) oxidant, liquid (gaseous) contaminant, and solid semiconductor photocatalyst meet and engage in an efficient oxidation reaction. The porous membrane has pores which have a region wherein the meniscus of the liquid varies from the molecular diameter of water to that of a capillary tube resulting in a diffusion layer that is several orders of magnitude smaller than the closest known reactors. By this apparatus, apart from photocatalyst, oxidizing agents (such as ozone, H2O2) have also been generated, which is harmful for outer environment.

[0016] US8557188B2A relates to an UV photocatalytic air purifier/sterilizer in which the multiple limited-lifetime components (such as the UV light, UV light electronics, and catalytic portion) of a photocatalytic UV air purifier/sterilizer are packaged together to form a single, handheld, unitized package, designed for easy insertion and removal into an air purifier. In a preferred embodiment, the device may package a series of stacked HO2 coated parallel metal catalytic plates, a UV germicidal lamp with a fluorescent tube form factor, and a UV lamp ballast into a single disposable or recyclable unit. Substrate plates are arranged at 90 degree, by which either only one edge or one side of plates is exposed to UV and thus not ensuring sufficient exposure.
[0017] KR10-1654160 Bl relates to an air sterilization device, which increases a UV exposure time of air inside the air sterilization device. According to an embodiment of the present invention, an air sterilization device comprises: a main body which provides a pathway for the air; an inlet port arranged on one side of the main body, and through which air flows; an outlet port arranged on the other side of the main body, and discharging the air flowed through the inlet port; a UV lamp which emits UV rays to the air; and a baffle including a penetration hole which the UV lamp penetrates, and a plurality of through-holes which air passes through. In this, various baffles are arranged to control the flow of air. However, holding air for some time within a system is difficult to be kept and thus the method of photocatalytic oxidation seems more effective since they do not require to hold the air.
[0018] US20150114822 Al provides a method of oxidizing VOCs to carbon dioxide and water in a photo catalytic environment by passing the VOC laden industrial effluent through a filter tube containing a porous inorganic substrate, impregnated and surface coated with HO2 powder, present within an Ultra Violet light/ozone/hydroxyl flux field. The porous inorganic substrate includes at least one multiple wavelength type UV C lamp of wavelengths between and/or in combinations of 185 and 285 nm. The lamp is placed in parallel and in the centre of the filter tube, allowing maximum radiation to reach the Ti02 surface to enhance its catalytic activity. The lamp is further

encapsulated in an air purged, UV transparent annular quartz tube to maintain an ambient temperature of less than 50° C. The purged air passing through the quartz tube further provides ozone/hydroxyl, formed by the contact of oxygen and humidity in the purged air with UV light, which assists in oxidation of volatile organic compounds. However, the parallel placement may not provide sufficient exposure of UV radiation.
[0019] A document titled as Performance of an innovative VUV-PCO purifier with nanoporous TiCh film for simultaneous elimination of VOCs and by-product ozone in indoor air, dated 2018-06-21 discloses an innovative vacuum ultraviolet photocatalytic oxidation (VUV-PCO) air purifier, consisting of a photocatalytic unit bearing nanoporous Ti02 film, an ozone removal unit bearing Mn-Fe catalyst and a radial fan, was designed and constructed. The performance of the VUV-PCO air purifier in simultaneous elimination of VOCs and O3 by-product was, for the first time, evaluated in a sealed actual room. A separate unit is required for ozone treatment. A single unit cannot take care of both chemical and microbiological contaminations. The separate ozone treatment unit might induce more cost.
[0020] In the above mentioned prior arts, they mostly utilizes honeycomb arrangement with parallel placement of UV lamps. In such type of arrangements, most of UV radiation gets wasted. None of the art evidences sufficient exposure of photocatalytic substrate to UV rays which maximises the efficiency of purifier. Also in the prior arts, separate units are used for ozone treatment, there is a need of a single arrangement which provides maximum exposure of photocatalytic substrate to UV rays and also treat ozone without any extra cost or extra unit. Also, there is a need of a device which has a single arrangement but capable of treating all three kinds of contaminants; microorganisms (such as bacteria, viruses in aerosols), chemical contaminants such as volatile organic compounds, ozone and particulate matter.
OBJECT OF THE INVENTION

[0021] Some of the objects of the present disclosure, which satisfy at least one embodiment herein, are listed herein below.
[0022] It is a general or primary object of the present disclosure to provide an air purification module which utilizes principle of photocatalytic oxidation.
[0023] The primary object of the present disclosure is to provide an air purification module which utilizes metal doped nano Ti02 (Titanium Dioxide) as photocatalyst.
[0024] It is another object of the present disclosure to provide an air purification module which provide a special arrangement of photocatalytic substrates to maximise exposure to UV radiations.
[0025] It is yet another obj ect of the present disclosure to provide an air purification module which provide a special arrangement of photocatalytic substrates which utilizes combination of UV sources with wide range of wavelength and thus become one step solution for treating vast range of contaminants present in air.
SUMMARY OF THE INVENTION
[0026] This summary is provided to introduce concepts related to an air purification module based on photocatalytic oxidation. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0027] In an aspect, the present disclosure provides an air purification module based on photocatalytic oxidation. The air purification module comprising: a housing having an inlet surface providing an aperture for sucking in air, an outlet surface providing an aperture for discharging the air and a peripheral surface between the inlet surface and outlet surface surrounding an interior area between the inlet surface and outlet surface. A plurality of UV source disposed in the interior area of the housing and

a plurality of metal plates coated with photocatalytic material arranged within the housing, exposed to UV rays emitted from the plurality of UV source. The plurality of UV source is capable of emitting rays of wide range of wavelengths and the plurality of metal plates are arranged at an angle with a normal plane wherein the angle is in the range of 105 to 110 degrees for maximum exposure to UV rays.
[0028] In an embodiment, the present disclosure provides that the air is sucked in through the inlet by an impeller attached with motor provided within the housing.
[0029] In another embodiment, the present disclosure provides that the housing is substantially cylindrical in shape.
[0030] In yet another embodiment, the present disclosure provides that the plurality of UV source comprises a combination of UV A and UV C sources.
[0031] In still another embodiment, the present disclosure provides that the wavelength of UV rays emitted from the plurality of UV source is in the range of 200 nm- 400 nm.
[0032] In preferred embodiment, the present disclosure provides that the metal plates comprise aluminum plates.
[0033] In further embodiment, the present disclosure provides that the aluminum plates have an effective surface area in the range of 0.5 m2-l m2
[0034] In preferred embodiment, the present disclosure provides that the plurality of metal plates (201) coated with photocatalytic material (203) which comprises Ti02 doped with palladium and silver, wherein the percentage of palladium and silver in the photocatalytic coating material is 1%.
[0035] In more preferred embodiment, the present disclosure provides that the plurality of metal plates coated with photocatalytic material which comprises titanium dioxide nano particles of approximately 100 nm blended with optimum, yet minor

percentage (1.0 %) of palladium, copper, silver and cobalt metals calibrated for best efficacy to oxidize hydrocarbons and carbon monoxide.
[0036] In an embodiment, the present disclosure the plurality of UV source is arranged in circumferential region of a ring type frame disposed in the interior area of the housing and the plurality of metal plates coated with photocatalytic material are arranged in interior of the frame within the housing, exposed to UV rays emitted from the plurality of UV source.
[0037] In another aspect, the present disclosure provides a method of purifying air by air purification module based on photocatalytic oxidation, the method comprising the steps of: sucking in air from an aperture provided at an inlet surface of a housing which has an outlet surface providing an aperture for throwing out the sucked air and a peripheral surface between the inlet surface and outlet surface surrounding an interior area between the inlet surface and outlet surface. The method further comprises providing a plurality of UV source disposed in the interior area of the housing and providing a plurality of metal plates coated with photocatalytic material arranged within the housing, and getting them exposed to UV rays emitted from the plurality of UV source and generating strong oxidizing hydroxyl radicals in vicinity of the plurality of metal plates. Then passing the sucked in air through the UV exposed metal plates and strong oxidizing hydroxyl radicals, to purify air, and then discharging out the purified air through the outlet surface of the housing. In this method, the plurality of UV source is capable of emitting rays of wide range of wavelengths and the plurality of metal plates are arranged at an angle with a normal plane wherein the angle is in the range of 105 to 110 degrees for maximum exposure to UV rays.
[0038] In an embodiment, the present disclosure provides that the said hydroxyl radicals oxidize air contaminants from the sucked in air.

[0039] In another embodiment, the present disclosure provides that the said contaminants include, volatile organic compounds, harmful gases, coarse and fine particulate matter.
[0040] In yet another embodiment, the present disclosure provides that the said contaminants are at least one of the benzene, toluene, formaldehyde, carbon monoxide, ozone and their mixtures.
[0041] In yet another embodiment, the present disclosure provides that the said hydroxyl radicals disintegrate microbiological contaminants include viruses, bacteria, molds, fungi, aerosols, etc.
[0042] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter.
[0043] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF DRAWINGS
[0044] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:

[0045] FIG. 1A illustrates the front view of the air purification module in accordance with an embodiment of the present disclosure;
[0046] FIG. IB illustrates the top view of the air purification module in accordance with an embodiment of the present disclosure;
[0047] FIG. 2 illustrate the arrangement of UV source and metal plates in accordance with an embodiment of the present disclosure;
[0048] FIG. 3 illustrates the cross sectional view of the metal plates in accordance with an embodiment of the present disclosure.
[0049] FIG. 4 illustrates the method of air purification in accordance with an embodiment of the present disclosure.
[0050] The figures depict embodiments of the present subj ect matter for illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF INVENTION
[0051] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0052] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and

embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0053] The terminology used herein is to describe particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0054] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0055] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0056] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the

present disclosure. The following description is, therefore, not to be taken in a limiting sense.
[0057] Hereinafter, a description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the present disclosure.
[0058] The present disclosure provides an air purification module which is based on the principal of photocatalytic oxidation. In present invention nano Ti02 are used as the photocatalyst. Ti02 absorbs photons from UV radiations and leads to the formation of reactive oxygen species (ROS) such as hydroxyl radicals. Metal doping is useful for increasing the charge separation efficiency of a photocatalyst and subsequently generating more ROS. In the present invention the efficiency of Ti02 semiconductor has been increased by doping it with palladium and silver in an optimum ratio.
[0059] The module comprises of 21 numbers of photo catalyst coated plates as shown in figure 2. These plates are aligned in a unique fashion in such a way to get maximum exposure of UV radiation leading to generation of hydroxyl radicals in more numbers. The module comprises of three UV source emitting UV radiations of wide wavelength range. It has been optimized for desired disinfection efficacy and maximum degradation of chemical pollutants present in the air.
[0060] The purification module based on photo catalytic oxidation is based on the selection of below mentioned four points:
• Formulation of Photocatalytic Coating Material: The most commonly used photocatalytic coating material is titanium dioxide. As an advancement in this technology Ti02 is now doped with several elements to increase its photocatalytic efficiency and ultimately purification efficacy. In the present disclosure, nano Ti02 is doped with noble metals such as palladium and silver in an optimum ratio to obtain the desired results.

• Coating Surface: Most commonly used coating surface is glass or ceramic. In the module of the present disclosure aluminium plates are used as the substrate for coating with photocatalytic material. These substrate plates are highly stable, provides strength and durability to the entire module. Added advantage of using aluminium plates is that the total effective surface area is around 0.5 m2-l m2, thus providing sufficient active surface for photocatalysis.
• Alignment of Plates: The coated aluminium plates are aligned at a certain angle in our module in order to get optimum exposure of UV radiations. These plates are tilted to an angle of 105 to 110 degrees as shown in FIG 3. The specific alignment and inclination angles of the plates leads to maximum exposure of UV radiations to the plates coated with photocatalytic material.
[0061] UV Source: In the earlier studies, single wavelength of UV source was used for photocatalytic activities. Purifiers which target microbiological contaminants are equipped with UV C radiation source and purifiers which target chemical contaminants are equipped with UV A radiation source. But in the module of present disclosure, a wide range of UV spectrum has been used which varies from 200 nm to 400 nm. The present technology covers the use of a combination of UV source with absorbance peak in both UV A and UV C ranges of the electromagnetic spectrum. Synergistic effect of both the UV ranges generates hydroxyl radicals in abundance and result in efficient photocatalytic oxidation in a short span of time. These OH radicals are strong oxidizing agents capable of efficiently mineralizing contaminants in a short span of time.
[0062] FIG. 1A illustrate the front view and FIG IB illustrates the top view of the air purification module. The present disclosure comprises a hollow cylindrical housing (100). The housing can be broadly divided in two parts; top part and bottom part. The bottom part has an inlet surface (101) providing aperture which allows outside air to sweep inside the air purification module. The inlet surface (101) are present on

circumferential aperture of the bottom section of the cylindrical housing (100). In addition to the major contaminants, one must also take into account the presence of nuisance components such as dust and aerosol particles that rapidly foul the photo catalyst surface, which can seriously limit the application of this method. A peripheral surface (106) extending from bottom part to top part surrounding an interior area. A set of pre filters (102) may be installed to improve the performance of the system. The working of the air purification module involves movement of air from the bottom section of the air purifier, through impeller (103) attached with motor (104). The surrounding air enters the air purification module from inlet surface (101), air travels along the hollow interior area of the air purification in axial motion. Arrows shown in the figure represent the movement of air. The air travels through hollow interior of the air purification module's housing and reaches the arrangement of metal plates in a frame (200) present in the interior of the top part of the housing (100).
[0063] FIG 2 illustrates the arrangement of UV source and metal plates. It comprises a plurality of metal plates (201) as substrate to coat photocatalytic material. It also has a ring type frame (200) contains multiple UV sources (202) fitted between those plates at appropriate distance. Both the surfaces of the metal plates are coated with photocatalytic material (203) arranged at an angle in the frame. Once the air reaches the top section, it interacts with the frame (200) containing photocatalytic plates (201). Outlet surface (105), shown in FIG IB are present on the top of the housing (100). The air dispenses out of the air purification module from the openings (105). The photocatalytic module disclosed can dispense air at a flow rate varying from 560m3h-1to950m3h-1.
[0064] FIG 3 illustrates the cross sectional view of the plates (201) coated with photocatalytic material (203). The figure demonstrates angle of inclination of the plates (201) in the frame (200) which falls in the range of 105 to 110 degrees. The figure also illustrates placement of UV source (202) in between plates (201).

[0065] The present disclosure invention provides a more efficient way to handle all three types of air contaminants: Physical, Chemical and Microbiological. It is a single-step solution to take care of air pollutants without using any filters.
[0066] This technology has a remarkable advantage over filter-based air purifier. Filter based technology is based on trapping of pollutants whereas this technology disintegrates wide variety of harmful pollutants (such as particulates, gaseous and microbiological) into the natural components of environment. Filters used in filter based air purifiers may become breeding ground for Bacteria. When we pull the filter out for cleaning or when the filter has reached its capacity, there are high chances of offloading of trapped contaminants back into the environment in high concentration.
[0067] The method of purifying air is shown in figure 4. In the module of present disclosure, metal doped Ti02 is used as the photocatalyst. Ti02 absorbs photons from UV radiations and electrons present in the valence band gets excited to conduction band, leaving holes behind. The photocatalytic activity depends on the ability of the catalyst to create electron-hole pairs, which generate ROS such as hydroxyl radicals (OH*) able to undergo secondary reactions. The plates coated with photo catalyst are tilted at an angle which falls in the range of 105-110 degrees. Since, the plates are aligned at specific angles the distance between the UV source and photocatalyst surface is minimal and hence better exposure of UV radiations on both surfaces of the plates can be achieved. The interaction of these UV radiations with Ti02 leads to the generation of significant amount of hydroxyl radicals in the proximity. As the air moves in between these plates, the contaminants present in the air interacts with generated hydroxyl radicals and gets effectively oxidized into simpler molecules.
[0068] The present disclosure invention is an eco-friendly technology which destroy a vast range of pollutants without generating harmful by-products.
[0069] Exposure of wide range of UV spectrum used in this module provides an extra edge. The wide range of UV spectrum produce large number of hydroxyl radicals

and disintegrate microorganisms and degrades all types of physical and chemical air contaminants in an effective manner.
[0070] Hydroxyl radicals generated in the module of present disclosure efficiently degrade volatile organic compounds such as toluene, formaldehyde, benzene, hexane, etc. The fine particulate matter and other harmful gases can be efficiently degraded into simpler molecules of carbon dioxide and water.
[0071] The air purification module of the present disclosure is capable of destroying ozone by photocatalytic oxidation. Ozone molecules present in the air are oxidized by hydroxyl radicals to form molecular oxygen.
[0072] The hydroxyl radicals generated in the present invention perform biocidal functions on microorganisms and degrade other airborne organic compounds to mineral forms of harmless compounds. These reactive free radicals interact with the micro-organisms present in the air and ruptures their cells walls, ultimately resulting in their disintegration.
[0073] Performance of the module has been enhanced by many folds by unique placement of photocatalyst coated plates in a confined space and using doped photo catalyst coating. This technology disintegrates wide range of harmful pollutants into the natural components of environment. This technology is pretty effective to complete the purification process in a comparatively shorter span of time leading to power saving.
Equivalents
[0075] The foregoing description of the preferred embodiment of the invention has been presented for illustration and description. It is not intended to be exhaustive, nor is it intended to limit the invention to the precise form disclosed. It will be apparent to those skilled in the art that the disclosed embodiment may be modified in light of the above teachings.

We Claim:

1. An air purification module based on photocatalytic oxidation, the air
purification module comprising:
a housing (100) having an inlet surface (101) providing an aperture for sucking in air, an outlet surface (105) providing an aperture for discharging the air and a peripheral surface (106) between the inlet surface (101) and outlet surface (105) surrounding an interior area between the inlet surface (101) and outlet surface (105);
a plurality of UV source (202) arranged disposed in the interior area of the housing (100);
a plurality of metal plates (201) coated with photocatalytic material (203) arranged within the housing (100), exposed to UV rays emitted from the plurality of UV source (202),
characterized in that, the plurality of UV source (202) is capable of emitting rays of wide range of wavelengths and the plurality of metal plates (201) are arranged at an angle with a normal plane wherein the angle is in the range of 105 to 110 degrees for maximum exposure to UV rays.
2. The air purification module as claimed in claim 1, wherein the air is sucked in through the inlet by an impeller (103) attached with motor (104) provided within the housing (100).
3. The air purification module as claimed in claim 1, wherein the housing (100) is substantially cylindrical in shape.
4. The air purification module as claimed in claim 1, wherein the plurality of UV source (202) comprises a combination of UV A and UV C sources.

5. The air purification module as claimed in claim 1, wherein the wavelength of UV rays emitted from the plurality of UV source (202) is in the range of 200 nm- 400 nm.
6. The air purification module as claimed in claim 1, wherein the metal plates (201) comprise aluminum plates.
7. The air purification module as claimed in claim 6, wherein the aluminum plates have an effective surface area in the range of 0.5 m2-lm2.
8. The air purification module as claimed in claim 1, wherein the plurality of metal plates (201) coated with photocatalytic material (203) which comprises Ti02 doped with palladium and silver, wherein the percentage of palladium and silver in the photocatalytic coating material is 1%.
9. The air purification module as claimed in claim 1, wherein the photocatalytic coating material (203) comprises Ti02 nanoparticles blended with palladium, copper, silver and cobalt metals, wherein the percentage of palladium, copper, silver and cobalt metals in the photocatalytic coating material is 1%.
10. The air purification module as claimed in claim 1, wherein the plurality of UV source (202) is arranged in circumferential region of a ring type frame (200) disposed in the interior area of the housing (100) and the plurality of metal plates (201) coated with photocatalytic material (203) are arranged in interior of the frame (200) within the housing (100), exposed to UV rays emitted from the plurality of UV source (202).
11. A method of purifying air by air purification module based on photocatalytic
oxidation, the method comprising the steps of:
sucking in air from an aperture provided at an inlet surface (101) of an housing (100) which has an outlet surface (105) providing an aperture for throwing out the sucked air and a peripheral surface (106) between the inlet surface and outlet surface surrounding an interior area between the inlet surface (101) and outlet surface (105);

providing a plurality of UV source (202) disposed in the interior area of the housing (100);
providing a plurality of metal plates (201) coated with photocatalytic material (203) arranged within the housing (100), and getting them exposed to UV rays emitted from the plurality of UV source (202) and generating strong oxidizing hydroxyl radicals in vicinity of the plurality of metal plates (201),
passing the sucked in air through the UV exposed metal plates (201) and strong oxidizing hydroxyl radicals, to purify air, and
discharging out the purified air through the outlet surface (105) of the housing (100),
characterized in that, the plurality of UV source (202) is capable of emitting rays of wide range of wavelengths and the plurality of metal plates (201) are arranged at an angle with a normal plane wherein the angle is in the range of 105 to 110 degrees for maximum exposure to UV rays.
12. The method of purifying air as claimed in claim 11 wherein the said hydroxyl radicals oxidize air contaminants from the sucked in air.
13. The method of purifying air as claimed in claim 11, wherein the said contaminants include, volatile organic compounds, and harmful gases, coarse and fine particulate matter.
14. The method of purifying air as claimed in claim 11, wherein the said contaminants are at least one of the benzene, toluene, formaldehyde, carbon monoxide, ozone and their mixtures.

15. The method of purifying air as claimed in claim 11, wherein the said hydroxyl radicals disintegrate microbiological contaminants include viruses, bacteria, molds, fungi, aerosols.