Description:FIELD OF THE INVENTION:
The invention generally relates to the field of air purification and sterilization, and more particularly it relates to a photocatalytic and antimicrobial material and its method of preparation for air purification and sterilization.

BACKGROUND OF THE INVENTION:
The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts, or common wisdom) that, while expected to be helpful to provide additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein or inferred thereupon.
Modern culture is increasingly concerned about indoor and outdoor air pollution. Airborne pollution still has a detrimental impact on people's health and, consequently, their quality of life, despite the fact that several air quality policies and regulations have been implemented globally over the past few decades. Certain liquids and solids release volatile organic compounds (VOCs) as gases in the air and considered as air pollutants. Many compounds are included in VOCs, some of which may have negative short- and long-term health impacts. Numerous volatile organic compounds (VOCs) have concentrations that are usually higher—up to ten times higher—indoors than outside. Reducing the quantity of airborne pollutants by decomposing them through photo induced reactions could be one way to tackle this issue.
Numerous attempts have been made and several prior art material and methods are known for air purification and sterilization. Even though these innovations may be suitable for the specific purposes to which they address, however, they would not be as suitable for the purposes of the present invention.
For example, Chinese Patent CN108868563 to Dong Fengliang et al. discloses a window screening and preparation method thereof to be purified the air of a room based on visible light photocatalysis. The window screening is prepared by coating Graphene oxide coated with silver doped titanium dioxide nano material on gauze material
For example, PCT Patent application WO2017190352 to Wang Jianyong discloses an air sterilizing purifier characterized by comprising a casing, a centrifugal device, a filtering device and a photocatalytic device, wherein the photocatalytic device comprises a light source and a photocatalytic film with a base layer, a three-dimensional graphene layer, a TiO2 nano-film layer and a nano-silver layer.
For example, Chinese patent application CN109482179 to Zhang Jie et al. teaches about a a kind of silver and the co-modified TiO2 of graphene. The composite photo-catalyst of formation is prepared by the method of mixing the graphene oxide dispersion solution, the AgNO3 solution, TiO2 powder and sodium citrate.
For example, Chinese patent application CN112354360A to Wang Yongbin et al. relates to a photocatalyst formaldehyde scavenger paint that comprises 1-10 parts of anatase type nano titanium dioxide, 1-10 parts (by weight) of copper-doped titanium dioxide, 1-10 parts of platinum-doped titanium dioxide, 3-5 parts of penetrating agent, 0.1-2 parts of nano silver, 1-3 parts of modified graphene and 50-93 parts (by weight) of deionized water in balance.
It is apparent now that numerous innovations that are adapted to a variety of material, devices and methods related to air purification and sterilization, which have been previously developed in the prior art that are adequate for various purposes. Furthermore, even though these innovations may be suitable for the specific purposes to which they address, accordingly, they would not be suitable for the purposes of the present invention. A small number of studies in recent literature based on graphene-TiO2 composites discuss the photocatalytic destruction of air pollutants, although the great majority of the literature deals with photocatalytic water treatment. The reduction of nitrogen oxides and the elimination of organic chemicals such as acetone and benzene are the subjects of those later works. Yet, there has never before been a single thorough investigation on the gas–solid phase photocatalytic removal of various hazardous organic compounds such as formaldehyde and mercaptan compounds) over TiO2-Silver- Graphene Oxide hybrid nanocomposites. Further, silver-graphene nanocomposite's antimicrobial qualities have previously known, but, simultaneous removal of VOC compounds and microorganisms, in a simple and effective way is the basis of the present invention, that overcomes the practical applicability, reusability and efficient use as an air filter with more efficacy is needed to overcome the drawbacks of the present prior arts.

SUMMARY OF THE INVENTION:
The purpose of the present invention is to provide a TiO2-Silver- Graphene Oxide hybrid nano-composite material that allows light-induced decomposition of organic contaminants in the realm of photocatalytic activity. The desired size of the TiO2 nanoparticles have remarkable potential as a material and the existence of desired size of the silver nanoparticles (Ag) along with Graphene Oxide (GO) may enhance its property. The method and preparation of TiO2-Silver- Graphene Oxide hybrid nanocomposite adopts a two-step simultaneous synthesis method. The procedures mostly involve the facile Co- precipitation synthesis method for TiO2 nanoparticles and then TiO2-Silver-Graphene Oxide nanocomposite in a water and Alcohol combination, which is followed by the deposition of silver (Ag) nanoparticles onto the synthesized binary nanocomposite using mercury lamp environment.
According to another aspect of the present invention, the nano-composite material shows strong anti-microbial action. The nano-composite material in the presence of silver nanoparticles bonded to TiO2 nanoparticles of appropriate bonding and size to exposes maximum surface are to provide more effective anti-microbial action through the destruction of E. Coli bacteria interacting with the nanocomposite's layers.
The present invention allows to overcome the above-mentioned conventional problems of the prior arts; therefore, it is an object of the present invention is to provide a novel TiO2-Silver-graphene oxide hybrid nano-composite material that can be used as a coting over a membrane/fabric/net like structure to provide better surface area to react with the VOCs due to the graphene oxide and the termination of VOCs due to TiO2 nanoparticles
Another objective of the present invention is to provide a hybrid nano-composite material having high photocatalytic reactivity for the hydroxyl radicles to convert reaction into H2O and CO2.
Another objective of the present invention is to provide a hybrid nano-composite material having visible light responses due to silver nanoparticles to allow the material to act effectively from wide range of visible spectrum and make the air purification process more efficient.
Another objective of the present invention is to provide a hybrid nano-composite material having long term stability due to the graphene oxide enhances the stability and durability of the catalyst, preventing agglomeration and maintaining its catalytic activity over multiple cycles of use.
Another objective of the present invention is to provide a hybrid nano-composite material has environmental compatibility as compared to conventional VOC degradation methods, such as thermal or chemical treatments, photocatalytic degradation using silver-graphene- TiO2 nanocomposites is more environmentally friendly. It does not produce harmful by-products or secondary pollutants, making it a sustainable approach for VOC remediation.
Another objective of the present invention is to provide a hybrid nano-composite material that allows to improve antibacterial qualities of the air filter coated with the novel material of the present invention. As a result of the hybrid combination of silver and TiO2, where GO facilitates Surface Plasmon Resonance, which enhances antibacterial activity by preventing bacterial growth through the denaturation of proteins found in bacterial cell walls.
Another objective of the present invention is to provide a hybrid nano-composite material can be used in the areas of air filtration, building materials, water splitting, textile, medical facilities including masks and PPE kits, automotive industries, etc.
Another objective of the present invention is to provide a hybrid nano-composite material can be used for residential and commercial purpose, industrial and institutional purpose, transportation and healthcare sectors, Govt. and regulatory agencies primarily to filter air from VOCs and microorganisms.
These and other objectives, advantages and aspects of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features in accordance with embodiments of the invention. The summary is not intended to limit the scope of the invention, which is defined solely by the claims attached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1A illustrates a FE- SEM images of the air disinfection and air purifying hybrid nano-composite material, in accordance with an embodiment of the present invention;
FIG. 1B illustrates Energy Dispersive X-ray Spectroscopy (EDS or EDX) spectrum image of the air disinfection and air purifying hybrid nano-composite material, in accordance with an embodiment of the present invention; and
FIG. 2 illustrates an image of a test report showing antimicrobial properties of the air disinfection and air purifying hybrid nano-composite material, in accordance with an embodiment of the present invention.
Like reference numerals refer to like parts throughout the various views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION:
The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific system and processes described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Throughout this specification the word “comprise” or variations such as “comprises or comprising”, will be understood to imply the inclusions of a stated element, integer or step, or group of elements, integers or steps, but not the exclusions of any other element, integer or step or group of elements, integers or steps. Specific dimensions and other physical characteristics relating to the embodiments disclosed herein are therefore not to be considered as limiting, unless the claims expressly state otherwise.
According to several embodiment of the present invention, a method of preparation of an air disinfection and air purifying photocatalytic nano-composite material that can be used as an active material for preparing air purifying membrane including fabrics, nets, etc. The nano-composite material coated fabric acts as air filter for air conditioners, window screens, filter material for face masks and other purposes where air purification is required. The nano-composite material has photocatalytic and antimicrobial property. Further, the invention focusses on the effective size of the nano-composite material that adds value for a long term and effective uses of the nano-composite material coated filter membrane. The present invention allows the filter membrane to be reused after a predetermined period of time, the membrane/fabric washed properly and immersed in a nano-composite material and DI water solution to coat the fabric again with the nano-composite material to make the filter membrane reusable as an air filter. The prefect size of the Ag and TiO2 nano-particles makes the fabric a better air filter and allows it to be reusable and environmentally friendly by reducing carbon foot prints.
According to an aspect of the present invention, a method of preparation of an air disinfection and air purifying nano-composite material, wherein the method comprises a first step of preparing TiO2 nanoparticle powder, wherein the preparation of TiO2 nanoparticles comprises the steps of mixing 1-10 parts of ethanol with 70-90 parts of methanol and stirred for 2-10 minutes to form a ethanol-methanol mixture, then adding 1-10 parts of Tetra Isopropyl Titanate (TIPT) or tetra-n-butyl titanate with 1-10 parts of the ethanol-methanol mixture and allowed to settle for 15-30 minutes to form turbid white precipitates, then filtering the precipitates and then washed with warm deionized (DI) water and then subsequently washed with organic solvents and then dried at temperature 70-100°C for 10 to 12 hours to achieve oxide free solid sample, then, the sample is allowed to get calcination at temperatures ranging from 300°C - 600°C, for 30 to 60 minutes, then it is crushed to obtain a uniform TiO2 nanoparticle powder; and a second step of preparing TiO2-silver-graphene oxide hybrid composite, wherein the preparation of the hybrid composite comprises the steps of preparing a first solution by mixing deionised (DI) water with isopropyl alcohol (IPA) or ethanol or methanol or a combination thereof in equal ratio and stirring for 5-10 minutes, then adding 1-10 parts of the obtained TiO2 nanoparticle powder is mixed with the first solution in an ultraviolet light environment or dark room and stirred for 60-180 minutes to form a yellowish second solution, then adding 1-10 parts of AgNO3 with 5-10 parts of the second solution and continuously stirred to form a third solution, then 0.1-5.0 parts of Graphene oxide (GO) is dissolved in DI water and sonicated for 1-3 hours to prepare a fourth solution, wherein the fourth solution is added to the third solution and stirred for 2-3 hours to form precipitates, then the precipitates are extracted and steam sterilized at a temperature 60°C to 240°C and at a pressure of 1-3psi, then the washed with DI water and organic solvents and dried at temperatures ranging from 60°C to 140°C for 10-15 hours to form TiO2-silver-graphene oxide hybrid nano-composite material that acts as an air disinfection and air purifying nano-composite material ready to be applied on a membrane to act as an air filter.
According to another aspect of the present invention, the air disinfection and air purifying nano-composite material prepared using the above method comprises 1-10 weight percent of graphene oxide; 50-70 weight percent of TiO2 nanoparticle of size 300 and 400 nm; and 30-50 weight percent of silver nanoparticles of size 100 and 200 nm.
According to another aspect of the present invention, the nano-composite material has photocatalytic and antimicrobial property.
According to another aspect of the present invention, the nano-composite material is mixed with DI water in a ratio 1:1 to 1:10. to make a solution that is applied as a coat on the membrane to form an air disinfection and air purifying membrane.
According to another aspect of the present invention, the membrane is a fabric made of hydrophilic material.
According to an embodiment of the present invention, a photocatalytic and anti-microbial nano-composite material when applied on a membrane/fabric, it acts as an air filter, thereby allowing light-induced decomposition of organic contaminants present in the air. The nano-composite material with the presence of TiO2 nanoparticles, Silver (Ag) nanoparticles along with Graphene Oxide (GO) allows decomposition of volatile poisonous compounds while enhancing air purification quality by its anti-microbial property. The TiO2-Silver-Graphene Oxide hybrid nanocomposite material of the present invention adopts a two-step simultaneous synthesis method. The method allows a first step of co-precipitation synthesis method for TiO2 nanoparticles and then second step of TiO2-Silver-Graphene Oxide nanocomposite in a water and Alcohol combination, which is followed by the deposition of silver (Ag) nanoparticles onto the synthesized binary nanocomposite using mercury lamp environment. The method of the present invention allows coupling titania with graphene (between 0.01 to 1.0 wt%) via a UV reactor technique with the goal to increase the photocatalytic activity of the resulting hybrid materials. The resultant hybrid photocatalyst is thoroughly characterized utilizing analytical methods like UV visible spectroscopy.
According to another embodiment of the present invention, the method of preparation of the photocatalytic and anti-microbial hybrid nano-composite material comprises two steps, the first step comprises preparation of TiO2 Nanoparticle, wherein the first step comprises mixing ethanol and methanol are mixed in various ratios, including 1:2, 1:4, 1:6, 1:8, 1:10, 1:12, and 1:14, and stirred for about 5 minutes, then adding Tetra Isopropyl Titanate (TIPT) or tetra-n-butyl titanate in proportions ranging from 1 to 8, depending on the ethanol-methanol mixture. The resulting solution is left undisturbed for 15 to 30 minutes until it achieved precipitate of turbid white appearance. Subsequently, the precipitate is extracted from the solution and washed with warm deionized (DI) water and organic solvents. Following this, the sample underwent drying in an oven for 10 to 12 hours so that the oxides can be evaporated. Afterwards, the sample is subjected to calcination at various temperatures, ranging from 100°C, 200°C, 300°C, 400°C, 500°C, and 600°C, for durations between 30 minutes to 180 minutes, to complete the synthesis process. Finally, the calcinated sample is crushed to obtain a uniform powder.
According to another embodiment of the present invention, the second step of the method of preparation of the photocatalytic and anti-microbial hybrid nano-composite material comprises the preparation of the TiO2-silver-graphene oxide hybrid composite, wherein the second step comprises preparing a first solution by mixing DI water with IPA, ethanol, methanol, or a combination of these solvents in equal ratios, followed by stirring for 5-6 minutes. An ultraviolet light environment or dark room is prepared for the subsequent reactions. TiO2 is added to the solution in quantities ranging from 1-10 parts and stirred for 5 to 30 minutes, resulting in the second solution of pale yellow, off-white, yellowish brown, or another color appearance indicative of the reaction. Subsequently, AgNO3 is added in amounts ranging from 1 to 10 parts, according to the ratio of the second solution comprising combined organic solvents with DI water to prepare a third solution. Then, 0.1-5.0 parts of Graphene oxide (GO) is dissolved in DI water and sonicated for 0.1-2 hours to form a fourth solution, then it is added to the third solution and stirred for 2-3 hours to form precipitates after 0.1-2 hours of reaction time, the precipitates are extracted through various filtration processes, thereafter it is subjected to different temperatures, ranging from 60°C to 240°C, using hydrothermal methods, steam sterilizers, or a combination thereof, under 2-3psi of pressure. Following this, the sample underwent washing with DI water and organic solvents before being dried in an oven at temperatures ranging from 60°C to 140°C for 1-12 hours to form TiO2-silver-graphene oxide hybrid nano-composite material that acts as an air disinfection and air purifying nano-composite material ready to be applied on a membrane to act as an air filter.
According to another embodiment of the present invention, the nano-composite material prepared by the method of the present invention shows exceptional results when Escherichia coli (E.Coli.) and S. Aureus growth are examined for the same samples in comparison to the solutions available in the prior arts. The nano-composite material of the present invention shows strong suppression to the inhibitory activity of the microorganisms.
According to an exemplary embodiment of the present invention, the charge of the nano-composite material is used to explain this discrepancy by altering the repulsive and attractive forces that exist between the nano-composite material surface and the cell membrane of the microorganisms. This results in wider inhibitory zones that are inaccessible to the Escherichia coli and S. Aureus bacterium. The current study's findings indicate a promising advancement in the field of enhancing the characteristics of metal oxides mixed with silver-graphene oxide in the field of antimicrobial property of TiO2-Silver-graphene oxide hybrid nano-composite material.
TEST METHODS
According to another exemplary embodiment of the present invention, the novel TiO2-Silver-graphene oxide hybrid nano-composite material is performed for a photo degradation experiment with organic toxic compounds like benzene, toluene, formaldehyde, xylene, hexane and mercaptan, the changes are captured and the photocatalytic property of this hybrid nanocomposite is investigated. The photocatalytic efficacy of the synthesized nano-hybrid is thoroughly examined for the breakdown of chemicals that are active constituents of the VOCs degradation. Also, our findings demonstrate the remarkable properties of the TiO2-Silver-graphene oxide hybrid material, which is synthesized with upto 1.0 weight percent graphene, as well as its superb appropriateness for a variety of multifunctional uses in the field of environmental remediation.
According to another exemplary embodiment of the present invention, the novel TiO2-Silver-graphene oxide hybrid nano-composite material is tested under a scanning electron microscope (SEM) to study the effect of the novel hybrid nano-composite material as an air filter. Under photocatalytic effect it is observed that the Ag nanoparticles and the TiO2 nano-particles creates an electron potential well to aid in the separation of electron-hole pairs. In the meantime, the transfer of photo-generated electrons is enhanced, recombination can be further decreased, and the photocatalytic reaction area is increased by combining titanium dioxide nanoparticles with GO materials that have good conductivity and electron capture performance.
The band gap energy and the UV visible measurement result are used to suggest and illustrate a potential photocatalytic mechanism in when visible light is irradiated on the air filtration fabric, the up-conversion feature of GO can excite both TiO2 and Ag both directly and indirectly. When long-wave light (? > 350 nm) is irradiated on GO, it can emit high-energetic light (? < 350 nm) to generate more (Electrons) e- -(Holes) h+ pairs, which enhances photocatalytic performance. TiO2 and Ag's Valance Band (VB) has h+, but the e- on the VB is generated and moved to the Conduction Band (CB). The photo-induced e- on the TiO2 CB will transfer to the Ag CBand the photo-induced h+ in the TiO2 VB transfer to the Ag VB, resulting in the photo-induced e- and h+ accumulation on the Ag, in accordance with the conventional type-I heterojunction mechanism (electrons and holes could easily migrated to lower band position). As, graphitic-like characteristics and presence of certain oxygen-rich groups, graphene oxide (GO) with a work function of 4.7–5.2 eV. Since electrons prefer to migrate to materials with a larger work function, a partial transfer of electrons from Ag to GO will occur. The e- on the GO and Ag would react with O2 to produce .O2-. The UV visible result indicates that ·OH is produced during the photocatalysis process. However, the accumulated h+ on the VB of Ag are unwilling to trigger –OH or H2O to create ·OH radicals. Consequently, the photo-induced electrons that are transported first mixed with O2 to form ·O2 -. Then, ·O2 - interacted with e- to produce ·OH (Equation. (1) to (3)), which oxidised the VOCs that is absorbed. Furthermore, h+ on the Ag VB has a strong oxidation property that can oxidise VOCs to a tiny molecule through a redox process, despite the fact that it cannot directly oxidise VOCs. Through a photodegradation reaction, VOCs are oxidised by all of the above active species (·OH, ·O2 -, and h+) and eventually mineralized into CO2, H2O, and other harmless small molecules. The enhancement of photocatalytic performance is facilitated by the interaction between the Ag SPR effect and the GO up-conversion property.
e- + O2 ? · O2- (1)
·O2- + h+ ? O- (2)
O- + H2O ? · OH + OH- (3)
Hydroxyl radicals (OH·) react with various organic compounds, producing water and typically forming radicals. Benzene, toluene, and xylene yield aromatic radicals, while methyl mercaptan forms a methylthiol radical. Hexane demonstrates multiple reaction sites, creating three different hexyl radicals. Formaldehyde stands out by producing formic acid, a stable product, instead of a radical. The following reactions showcase the diverse interactions between hydroxyl radicals and organic molecules, highlighting the radical's ability to abstract hydrogen atoms from different chemical structures.

According to another embodiment of the present invention, the antimicrobial properties of TiO2-silver-graphene hybrid nanocomposite, under light irradiation, demonstrates outstanding photocatalytic antimicrobial activities against Escherichia coli (E. coli). After 30 to 180 minutes of visible light irradiation, all bacterial environments, E. coli—are nearly 100% disinfected. The superior photocatalytic self-cleaning and bacterial cell analysis by TiO2-silver-graphene hybrid nano-composite material is prepared by the hot electrons from Ag nanoparticles that are injected by surface plasmon resonance, which is induced by visible light excitation, into the conduction band of TiO2. Reactive oxygen species are produced in large quantities as a result of simultaneous charge separation, which is facilitated by the graphene counterpart.
According to another embodiment of the present invention, as shown in Fig. 1A-B, SEM/EDS studies revealed the microscopic, characteristics of the as-prepared TiO2 nanoparticles, confirming its chemical composition and crystal structure as being the result of the applied preparation method of the present invention. Fig. 1A shows the nano-composite material under a scanning electron microscope (SEM) showing a collection of spherical particles, some larger than others. The particles seem to have a rough, uneven surface with numerous tiny protrusions and indentations. The scale bar in the grayscale image shows that the particles are roughly 100 nanometers in size. The finding under the SEM revealed that graphene oxide is retaining silver and TiO2 nanoparticles in the 100–400 nm range. TiO2 nanoparticles are brighter than silver nanoparticles and fall between 300 and 400 nm in size. Silver nanoparticles, which are lighter and have a particle size between 100 and 200 nm, and TiO2 nanoparticles, which are brighter and have a particle size between 300 and 400 nm, are observed. The Fig. 1B shows that the particles are agreeably synthesized, and their spherical morphology suggests that their increased surface to volume ratio allows them to interact with volatile organic compounds (VOCs) more quickly. Also, the Energy Dispersive X-ray Spectroscopy (EDS or EDX) spectrum discloses the elemental composition of the nano-composite material and correlating with the SEM results. The key elements identified in the spectrum are Carbon (C), Oxygen (O), Nitrogen (N), Silver (Ag), and Titanium (Ti).
According to another embodiment of the present invention, the spectrum shows a significant peak for Carbon, indicating a high presence of carbon in the sample. There is also a notable peak for Oxygen, suggesting the presence of oxides or organic compounds. A smaller peak for Nitrogen indicates a minor amount of nitrogen in the sample. The X-axis of the spectrum represents the energy levels of the detected X-rays, ranging from 0 to 18 keV, while the Y-axis shows the number of X-rays detected at each energy level, indicating the relative abundance of each element.
Two peaks for Silver are observed, one at around 0.9 keV and another smaller one at around 3 keV, indicating the presence of silver. Similarly, two peaks for Titanium are seen, one at around 0.8 keV and another smaller one at around 4.3 keV, suggesting the presence of titanium. The instrument settings used for the analysis include an accelerating voltage (kV) of 10, a magnification (Mag) of 8000, a takeoff angle of 27.56, a live time of 30 seconds, an amplifier time of 3.84 microseconds, and an energy resolution of the detector at 130.5 eV using the Element-C2B detector.
Interpreting the spectrum, the high peak for carbon suggests that the sample is carbon-rich, possibly an organic material or a carbon-based compound which is graphene oxide in reduced form. The presence of oxygen and nitrogen indicates the potential existence of organic compounds or oxides at the nanometer level. The peaks for silver and titanium suggest that these elements are present in smaller quantities, potentially as the composite material having the lower deficiency as per the formulation we have discussed in the upcoming section of process methods. In conclusion, the EDS spectrum indicates that the sample is primarily composed of carbon, with significant amounts of oxygen and smaller amounts of nitrogen, silver, and titanium. This composition is signifying the material we have synthesized is into the nanometer scale also, the surface modifications are accurate as per the significance of composition.
According to another embodiment of the present invention, as shown in Fig. 2, the nano-composite material anti-microbial action is tested on the surface of the air filter membrane coated with the material of the present invention. It is found that the nano-composite material acts excellent and shows more efficacy in the presence of silver nanoparticles bonded to TiO2 in the nano-composite material of the present invention to provide anti-microbial action through the destruction of E. Coli bacteria interacting with the nanocomposite's layers.
Because many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalence.
, Claims:We Claim:
1. A method of preparation of an air disinfection and air purifying nano-composite material, wherein the method comprises:
a) preparing TiO2 nanoparticle powder, wherein the preparation of TiO2 nanoparticles comprises the steps of mixing 1-10 parts of ethanol with 70-90 parts of methanol and stirred for 2-10 minutes to form a ethanol-methanol mixture, then adding 1-10 parts of Tetra Isopropyl Titanate (TIPT) or tetra-n-butyl titanate with 1-10 parts of the ethanol-methanol mixture and allowed to settle for 15-30 minutes to form turbid white precipitate, then filtering the precipitate and then washed with warm deionized (DI) water and then subsequently washed with organic solvents and then dried at temperature 70-100°C for 10 to 12 hours to achieve oxide free solid sample, then, the sample is allowed to get calcination at temperatures ranging from 300°C - 600°C, for 30 to 60 minutes, then it is crushed to obtain a uniform TiO2 nanoparticle powder; and
b) preparing TiO2-silver-graphene oxide hybrid composite, wherein the preparation of the hybrid composite comprises the steps of preparing a first solution by mixing deionised (DI) water with isopropyl alcohol (IPA) or ethanol or methanol or a combination thereof in equal ratio and stirring for 5-10 minutes, then adding 1-10 parts of the obtained TiO2 nanoparticle powder is mixed with the first solution in an ultraviolet light environment or dark room and stirred for 60-180 minutes to form a yellowish second solution, then adding 1-10 parts of AgNO3 with 5-10 parts of the second solution and continuously stirred to form a third solution, then 0.1-5.0 parts of Graphene oxide (GO) is dissolved in DI water and sonicated for 1-3 hours to prepare a fourth solution, wherein the fourth solution is added to the third solution and stirred for 2-3 hours to form precipitates, then the precipitates are extracted and steam sterilized at a temperature 60°C to 240°C and at a pressure of 1-3psi, then the washed with DI water and organic solvents and dried at temperatures ranging from 60°C to 140°C for 10-15 hours to form TiO2-silver-graphene oxide hybrid nano-composite material that acts as an air disinfection and air purifying nano-composite material ready to be applied on a membrane to act as an air filter.
2. The method as claimed in claim 1, wherein the air disinfection and air purifying nano-composite material prepared using the method comprises:
a) 1-10 weight percent of graphene oxide;
b) 50-70 weight percent of TiO2 nanoparticle of size 300 and 400 nm; and
c) 30-50 weight percent of silver nanoparticles of size 100 and 200 nm.
3. The nano-composite material as claimed in claim 2, wherein the nano-composite material has photocatalytic and antimicrobial property.
4. The nano-composite material as claimed in claim 2, wherein the nano-composite material is mixed with DI water in a ratio 1:1 to 1:10. to make a solution that is applied as a coat on the membrane to form an air disinfection and air purifying membrane.
5. The membrane as claimed in claim 4, wherein the membrane is a fabric made of hydrophilic material.