The Introduction of Dahlia Nano-TiO 2 coated Functional Tiles

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Eleanore Doyle
6 years ago
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1 The Introduction of Dahlia Nano- 2 coated Functional les 1. Introduction With the improvement of living standards, the living environment becomes more important. People want to live in a comfortable, clean and healthy environment. owever, modern living environment cannot fulfil this requirement. Luxurious decoration and sumptuous furniture are invisible pollution sources. They continuously release toxic organic substances into the air, such as formaldehyde, toluene and so on. At the same time, with the increase of these aerial pollutants and dust, the dust-stains which adhere to the external walls and glass of buildings, not only affect the city's cleanliness, but also are difficult to clean. If people live in such environment, the harm to the human body is self-evident. Modern scientific researches have proven that nano-titanium dioxide ( 2 ) in its anatase form has very beneficial photo-catalytic properties under the irradiation of ultraviolet light (from the sunlight); the majority of organic pollutants will be decomposed into harmless carbon dioxide and water. The surfaces of Dahlia Nano- 2 functional tiles are coated with nanotitanium dioxide films, and under the sunlight (UV) irradiation the tiles have the following proven functions: Ⅰ.Self-Cleaning Under the irradiation of light, 2 will play the role of self-cleaning by decomposing the oil and organic substances that come in contact with the surface of the tiles. The tiles are also super-hydrophilic. That means that with just the rinsing of water, the oil attached to the tiles surface will be washed away. ence, the pollutants are easily removed.

2 Ⅱ.Self-Sterilising Now, most of the anti-bacterial products are either organic or inorganic. If bacteria absorbs the ingredients of these anti-bacterial products, the bactecidal effect is limited and slow in reaction. Comparatively, the nano- 2 on the tile surface will destroy the cell membrane in a very short time with the irradiation of ultraviolet light (sunlight); and further decompose them into carbon dioxide and water. Ⅲ. Air Purification There are a variety of air pollutants and irritants around us, such as nitrogen oxides, aldehydes and other harmful gases; the stench of substances, such as rotten food, animal and poultry s excretion, etc. Under the irradiation of ultraviolet light, Dahlia Nano- 2 tile can decompose organic pollutants in the air (such as toluene, formaldehyde produced during home decoration process; fumes produced by cooking; nicotine, tar produced by smoking), and improve the air quality and protect people from air pollution, without resorting to expensive electrical and mechanical devices. 2. The Function and Principle of 2 The Nano- 2 coatings on the surface of the Dahlia Nano- 2 tiles ensure that the functions mentioned above are possible. In the photocatalytic reaction, 2 acts as the photocatalyst. During the whole reaction, the catalyst itself does not change, but it can effectively promote the chemical reaction. Thus, under the irradiation of light, all material which possess the function of catalysis are term photocatalysts. In fact, the most common photocatalyst is the chlorophyll. In photosynthesis, chlorophyll absorbs sunlight to produce carbohydrates and oxygen, and the chlorophyll does not change during the entire reaction. The photosynthesis cannot be carried out without the sunlight being absorbed by the chlorophyll. In this case, "Chlorophyll" can appropriately be referred to as a "photocatalyst. In the photocatalytic reaction with 2, 2 is equivalent

3 to the chlorophyll in the photosynthesis, and it is the photocatalyst in the reaction. Light Light C Chlorophyll absorbs light The decomposition reaction of water is a slow. owever,if there is organic matter, the decomposition rate is increased. tanium dioxide absorbs light Figure 1 There is basically resemblance between plant s photosynthesis and 2 photocatalytic reaction With the significant industrial development, convenience in life is proportional to the increase in the consumption of fossil fuels. At the same time, a lot of harmful pollutants are produced. In order to solve this problem, we must consider it from the material cycle perspective on the earth. What the world needs now is the technology that turns the pollutants into carbon dioxide and water with the natural energy, and it seems that the photocatalytic technology is what we should be aiming for. We should allow the amount of the natural fuels consumed by human activities gradually return to the original status by using natural energy through artificial technology (photocatalysis technology).

2 Pollutant + 2 C 2 + 2 Consumption Fossil fuels, chemical 2 photocatalytic reaction rganic matter + 2 C 2 + 2 Photosynthesis Figure 2 understanding the environmental photocatalytic purification

4 2 Pollutant + 2 C Consumption Fossil fuels, chemical 2 photocatalytic reaction rganic matter + 2 C Photosynthesis Figure 2 understanding the environmental photocatalytic purification technology based on the view of natural material cycle tanium dioxide and light are two key factors in the photocatalytic reaction. It will require a lot of effort to achieve the maximum efficacy, regardless of the change of the way, the basic mechanism of the technology will be invariable: the two phenomena on the surface of titanium dioxide after the absorption of light: Ⅰ. Photocatalytic xidation and Decomposition 2 is a N-type semiconductor. The band gap is 3.0eV, which belong to the excitation scope of ultraviolet (380nm). The electron (e - ) on the valence band of 2 can be excited to the conduction band with the effects of light; at the same time, the corresponding hole (h + ) appears on the valence band. The electrons and the holes diffuse on the surface of the titanium dioxide. The h + and e - react with the 2 - adsorbed on the 2 surface, then generate and 2 which are high-activity groups. The active oxygen and hydroxyl groups which have strong oxidation functions can decompose formaldehyde, methylamine and other harmful organic compounds, effluvium of pollutants and bacteria into harmless C 2 and 2. Based on this characteristic, nano- 2 has the following capabilities:

5 (a). The Strong Ability to Decompose the Pollutants: Bacteria, viruses are everywhere, such as in hospitals, shopping malls, stations, homes, sanitary wares, underwear, and so on. There are a large number of bacteria and viruses which seriously threaten people's lives and health. Under natural light, lighting, especially UV light irradiation and if the nano-titanium dioxide photocatalyst is placed in an appropriate manner at the above-mentioned places, a variety of bacteria and virus will be killed efficiently, quickly and thoroughly with the natural air flow. In addition, the bacteria, viruses and micro-organisms which have resistance to the common disinfectants can also be easily decomposed. In tests conducted on various types of common bacteria, after 24 hours the bacterial kill-rate have been recorded as more than 90% in the confined rooms whose walls have been coated by 2. So that the security of people's living environment will be enhanced greatly. (b). The Function of Decontamination of Air With the development of society, high-rise buildings and individual household s decoration has become vogue. owever, the environmental impact of decorating materials is catastrophic, releasing formaldehyde, benzene, amine and other harmful gases into the air. These have harmed people's lives and health. In addition, the pollution of C, S 2, N and other exhaust gases have always impacted our personal life, and people's living environment has become worse. Nano-titanium dioxide photocatalyst has the beneficial function to decompose the above harmful gases and other organic matter into C 2 and 2. The removal rate of harmful gases will be more than 90% with having the catalyst in the just-decorated rooms. With the comprehensive applications of photocatalyst, the air pollution will be reduced or completely removed, and the air will be fresh. (c). The Effect on Sewage Treatment

6 Nowadays, the environmental problem has attracted more and more attention. At the same time, people have paid a heavy price on it. The Chinese Government have committed to improve the environmental condition, the nation and enterprises spend a great deal of manpower, material and financial resources to control the pollution, in order to create a great environment for their citizens. According to the features and experimental results of nano-titanium dioxide photocatalyst, it can decompose most of the organic compounds in industrial wastewater. The macro-molecule organic compounds in the waste-water which are produced by paper mills, printing and dyeing mills, ethanosl producing plants and chemical plants together with formaldehyde and other pollutants mentioned above, are also decomposed into C 2 and 2. This is the beneficial properties of the titanium dioxide photocatalyst. (d). The Use of Nano 2 on the Anti-Bacterial Fabric Presently, the trend on the research, application and development of nanomaterials in the textile industry is generally divided into three ways: adding the Multifiber, mixture of various powders and multi-functional complex. Through the applications, we can develop the anti-ultraviolet type, anti-bacterial and deodorant type, infrared reflection type, and cooling type, water-resistant type, pollution prevention type, conductive type, flame-retardant type and other functional type of new products. This is the principle behind the use of nano-materials in the textile industry. At present, a variety of nano-fibers have been produced using the method of adding nano-materials into the spinning solution. Likewise, anti-bacterial and deodorant fibers have been made by mixing Nano- 2 powder into a polymer. Nano anti-bacterial dacron products can be widely used in knitted underwear, sports clothing, socks, carpets, medical sheets, clothing for the surgical and in-patient services, food industry professionals uniforms, as well as beddings, coverings for furniture, decorative fabrics and all kinds of underwear, clothings, non-woven fabrics, etc. Since Japan developed the deodorant fibers in 1984, new nano products have been increasing in the markets. The research and development of other antiultraviolet radiation nano-fiber and functional infrared fibre products have made great progress.

7 2 自由羟基羟基离子 - 超氧阴离子 e ( 电子 ) δ + 被捕获空穴 Figure 3 the role of 2 on surface Ⅱ. Super-ydrophilicity Lig Lig h 2 C C (a (b xidize the slowly adsorbed oil with the effect of d ii Water slides between the surface and decomposed oil il l h f Figure 4 the self-cleaning effects of the two major characteristics of 2

8 hv(h + ) 暗处 Dark (h t + ) Figure 5 changes of surface structure causes the changes to 2 hydrophilicity Photo-induced changes of hydrophilicity, for one thing, is due to the absorption and the decomposition of organic matter on the surface of 2 under the irradiation of the light. owever, the more important reason is the change of surface structure with the increase of the surface hydroxyl groups. The mechanism of the photoinduced changes of hydrophilicity which is caused by the changes of surface structure is shown in Figure 5. In the photocatalytic reaction,the light-generated hole spreads to the surface, then captured by oxygen in the crystalline form to generate free radicals or oxidize the adsorbed material. After the capture of the hole by Lattice oxygen, - chemical bond length becomes longer. Under the irradiation of light, the interaction between the hydroxyl in coordination with defective oxygen and 2 weakens. At the time, adsorbed water and the coordinate to form new surface hydroxyl groups. The hydroxyl density on the surface of 2 increases. In the dark, the surface of titanium dioxide gradually restored to the original weak hydrophilicity with the reduction of surface hydroxyl groups, so the light generated surface hydroxyl groups are in a thermodynamic instable

metastability. After the irradiation of light, the surface free energy of 2 turns higher than that of the pre-illumination, so it will be super hydrophilic. 3.

9 metastability. After the irradiation of light, the surface free energy of 2 turns higher than that of the pre-illumination, so it will be super hydrophilic. 3. Characterization and Performance of Product Ⅰ. Proving existence and the Effective Crystalline Form of 2 The spectrum analysis shows that, Dahlia Nano- 2 contain not only silicon, oxygen, sodium, calcium, nitrogen, phosphorus, magnesium and other ordinary elements, but also the element titanium which common tiles don t have. It indicates that there are nano- 2 films on the surface of Dahlia nano- 2 tiles. Figure 6 the surface electron energy spectrum of Dahlia nano- 2 tiles Figure 7 the XRD spectrum of Dahlia Nano- 2 ceramic tiles

There are two common types of crystalline forms for 2 : rutile and anatase. The former doesn t have photo-catalytic properties, and is mainly used in white dope, paint and cosmetics.

10 There are two common types of crystalline forms for 2 : rutile and anatase. The former doesn t have photo-catalytic properties, and is mainly used in white dope, paint and cosmetics. The latter has high photocatalytic properties, and is also the type we need. The XRD spectrum verifies that the crystalline form of the 2 film on the surface of Dahlia Nano- 2 ceramic tiles is anatase. Ⅱ. Super ydrophilicity At the interface between solid, liquid and gas phases, the angle between the solid-liquid interface to the gas-liquid interface is called the contact angle, usually expressed as θ (showed in the figure 8). We study the degree of hydrophilicity through the measurement of the contact angle, the smaller the contact angle is, the better the hydrophilicity will be; and the bigger the contact angle is, the worse the hydrophilicity will be. Figure 8 the contact angle between liquid and solid surface We irradiated the cleaned common tiles and nano- 2 ceramic tiles respectively under the ultraviolet light, then measured the contact angle at different times, as the duration of the illumination time increases, the contact angle decreases. owever, the contact angle of 2 ceramic tiles decreases faster, comparing to that of the common tiles. When the irradiation time reached 270min, the contact angle of 2 tiles reduced to 6, and the contact angle of the common tiles remained at 30. This proves that the nano- 2 tiles through the irradiation of UV light will be super hydrophilic (less than 10 ).

The contact angle of common tiles still stayed at 30 through the irradiation of UV light for 270min The contact angle of Nano- 2 tiles reached 6 through the irradiation of UV light for

Dahlia Nano- 2 tiles and common tiles Ⅲ. The Photodegradation of Benzene C t /C 0 1.02 1.00 0.98 0.96 0.94 0.92 0.90 0.88 0.86 0.84 0.82 0.80 0.78 0.

11 The contact angle of common tiles still stayed at 30 through the irradiation of UV light for 270min The contact angle of Nano- 2 tiles reached 6 through the irradiation of UV light for 270min θ o ) Contact angle ( blank nano 2 tile Irradiation time(h) Figure 9 the contact angle comparison of Dahlia Nano- 2 tiles and common tiles Ⅲ. The Photodegradation of Benzene C t /C Blank Nano 2 tile irradiation time (h) Figure 10 the photodegradation ability comparison of Dahlia Nano- 2 tiles and common tiles C t : the concentration of benzene at t time; C 0 : the initial concentration of benzene

12 Under the same conditions, the speed at which Dahlia nano- 2 tiles degrade benzene was faster than that of the common tiles. This indicated that Dahlia nano- 2 tiles have excellent efficiency in the decomposition of organic pollutants. Ⅳ. Anti-Bacterial Properties The comparison on the antimicrobial tests were carried out on the common tiles and the Dahlia nano- 2 tiles. The bacteria were Staphylococcus aureus and Colon bacillus, being the 2 most common types in the environment. After the irradiation of ultraviolet light for a certain period of time, the bacteria which had been introduced onto the tiles were placed in nutrient-rich solutions culture, and then we monitored the antibacterial property through observing the growth of bacteria. Table 1 the antimicrobial test results of common tiles and Dahlia nano- 2 tiles (College of Pharmacy, Suzhou University) As Table 1 shows, with the irradiation for only 8 minutes, Dahlia nano- 2 tiles have a very significant inhibitory effect on Staphylococcus aureus and Colon bacillus. The antibacterial rate was more than 90%, while the antibacterial rate of common tiles was only 25%. In conclusion, Dahlia nano- 2 tiles have good anti-bacterial properties. Under the same experimental conditions, in accordance with national standards of China (GB), we studied the anti-bacterial performance of Dahlia nano- 2 tiles through researching the resistance of Staphylococcus aureus on the surfaces of Dahlia nano- 2 tiles respectively. (Main wavelength of UV lamp was 365nm, the light intensity on the sample surfaces were 0.1mw/cm 2 and the irradiation time was 24h).

13 Table 2 the anti-bacterial test results of Dahlia nano- 2 and common tiles (Test Center of Antimicrobial materials, Technical Institute of Physics and Chemistry, Chinese Aacademy of Science) As Table 2 shows, with the irradiation for 24h, Dahlia nano- 2 white tiles had great inhibitory effect to Staphylococcus aureus, the antibacterial rate of Dahlia nano- 2 white tiles were more than 99%, and the antibacterial rate of Dahlia nano- 2 gray tiles were 95%, while the common tiles didn t have anti-bacterial performance. So it can be concluded that the Dahlia nano- 2 tiles have good antibacterial properties. Ⅴ. The Abrasion Test of Dahlia Nano- 2 les According to China s National Standards GB (the resistant determination of coatings), the surfaces of Dahlia nano- 2 tiles were scrubbed with the bristle testbrush repeatedly for a 1000 scrub cycle. After the tests, it was proven that the quality of the coating was not affected. This shows that 2 nano-particles bonded with the surfaces of ceramic tiles strongly; and the nano- 2 film wouldn t break away from the surface of tiles with standard mechanical force. 4. The Limitations of the Product 2 is not photocatalytic and hydrophilic without light, so the extent of the illuminated area is of importance. Considering the use of photocatalysis and the illumination area, it is favorable to spread the Dahlia nano- 2 tiles on the external walls of the buildings or if used indoors, the tiles must be illuminated by fluorescent

14 light or natural light. As we know, the pollution has been one of the biggest problems facing the entire world, and the best way is to eliminate it from the source of pollution. Nowadays, the technology to semi-permanent removal of pollutants combining with the non-depleting solar energy and 2 is no doubt the best way.

3.30 TITANIUM DIOXIDE

181 3.30 TITANIUM DIOXIDE Technology Prospects Addressable market size 5 Competitive landscape 3 IP landscape 4 Commercial prospects 4 Technology drawbacks 3 Total score (out of max. 25): 19 3.30.1 Properties