Application of Titanium dioxide

Industrial applications

Titanium dioxide is an important white pigment and porcelain glaze. Used in paint, ink, plastic, rubber, paper, chemical fiber, watercolor pigment and other industries.

Titanium dioxide is the whitest thing in the world. One gram of titanium dioxide can paint an area of more than 450 square centimeters white. It is five times whiter than the commonly used white pigment – lithopone, so it is the best pigment for white paint. The amount of titanium dioxide used as pigment in the world is more than 100000 tons a year. Titanium dioxide can be added to the paper to make it white and opaque, and the effect is 10 times greater than that of other substances. Therefore, titanium dioxide should be added to banknote paper and art paper.

In order to lighten the color of plastics and soften the luster of rayon, titanium dioxide is sometimes added.

In the rubber industry, titanium dioxide is also used as a filler for white rubber.

The photochemical properties of semiconductor titanium dioxide have made it useful in many fields, such as air, water and fluid purification. Photocatalysts doped with carbon or other heteroatoms can also be used in sealed spaces or areas with scattering light sources. When used in coatings on buildings, pedestrian slabs, concrete walls or roof tiles, they can significantly increase the decomposition of air pollutants such as nitrogen oxides, aromatics and aldehydes.

Ultrafine titanium dioxide has excellent ultraviolet light shielding and transparency. It is widely used in cosmetics, wood protection, food packaging plastics, durable household films, man-made and natural fibers, and transparent coatings. The special optical effect in the metallic flash coating makes it be valued and applied in the high-grade car paint.

Titanium dioxide is a semiconductor with small particle size, large specific surface area, loose porosity and rough surface. It is widely used as the photoanode material of dye-sensitized solar cells. Most researchers take titanium dioxide as the prototype, modify it by hydrothermal method, electrostatic spinning method and other methods, and use metal substances, inorganic substances and other doping reactions to prepare photoanode with excellent performance, The dye-sensitized solar cell was assembled.

Titanium dioxide can effectively prevent the uncontrolled growth of microorganisms by virtue of photocatalysis, thus reducing the amount of harmful components in the environment. The antibacterial mechanism is that titanium dioxide is activated by light, and the interaction between electron hole pairs and oxygen molecules and hydroxide ions excites free radicals to cause chain reaction, destroy bacterial protein, and achieve the effect of sterilization.

Food application

The Food and Drug Administration of the United States stipulates that titanium dioxide can be used as a white pigment in all foods, and the maximum dosage is 1g/kg. The pigment additive titanium dioxide can be safely used in general colored foods, subject to the following provisions:

(1) The amount of titanium dioxide shall not exceed 1% of the weight of food.

(2) According to the special standards published in Article 401 of the decree, colored foods that are not allowed to be used, unless there are similar standards that allow the addition of pigments.

(3) For colored food, the edible pigment additive titanium dioxide can contain appropriate diluent as a safe pigment additive, as follows: silicon dioxide, as a dispersant additive, the content shall not exceed 2%.

Product adaptation: cold fruits, jelly, fried food, cocoa products, chocolate, chocolate products, hard candy, polishing candy, gum based candy, puffed food, candy chocolate product coating, mayonnaise, salad jam, jam, solid drinks, konjac gel food, etc.

environmental protection

Purified air

Titanium dioxide, as the catalyst of light coating pigment, is not only a kind of environmentally safe cleaner, but also can save energy and protect environmental resources.

Early Japanese and British scientists applied titanium dioxide to the pavement surface of urban roads to clean the road air. Titanium dioxide can be mixed with asphalt to reduce pollutants in the air. When cars pass by, concrete or asphalt containing titanium dioxide can purify the air and eliminate 25% to 45% of nitrogen oxides in vehicle emissions. When titanium dioxide is coated on the concrete surface, its air cleaning effect is also significant.

Cooling the earth

In May 2012, British scientists put forward a bold idea. They believed that the goal of cooling the earth could be achieved by spraying enough titanium dioxide into the stratosphere to reflect sunlight, which could effectively offset various adverse climate factors caused by global warming.

Because titanium dioxide can effectively reflect the direct sunlight, and its properties are stable, it has a good covering ability. If it is sprayed in the stratosphere, it can play a long-term role. British scientists proposed that high-altitude balloons could be used to bring this chemical into the stratosphere, and then release it. Once titanium dioxide is evenly distributed in the earth’s stratosphere, it can effectively reflect sunlight, thus cooling the earth.

Peter Davidson, a chemical engineer and president of Davidson Technology, a British consulting company, is the head of the project. He said that only 3 million tons of titanium dioxide need to be transported to the earth’s stratosphere to form a protective layer with a thickness of 1 mm in the earth’s stratosphere, but it can play a huge role – enough to offset the greenhouse effect caused by twice the current carbon dioxide content in the atmosphere.

Sunscreen cosmetics

Due to the great harm of ultraviolet rays to human body, developed countries have paid more attention to the research and development of sunscreen products in recent years, and have successively launched a variety of anti ultraviolet fibers, plastics, films, coatings, as well as sunscreen cream, foundation make-up, lipstick, mousse, baking cream and other anti sun cosmetics. In recent years, China has also increased the research and production of sunscreen cosmetics.

However, in the past, sunscreen agents were mostly benzophenones, o-aminobenzophenones, salicylates, p-aminobenzoic acids, cinnamates and other organic compounds, which were unstable, short in life, and had large side effects, with certain toxicity and irritation. If added too much, it would cause chemical allergy, and even lead to skin cancer. As an inorganic component, nanometer titanium dioxide has excellent chemical stability, thermal stability and non-mobility, strong achromatic power and covering power, low corrosivity, good dispersibility, non-toxic, tasteless, non-irritating, safe use, and also has the function of sterilization and deodorization. More importantly, as mentioned earlier, nano-titanium dioxide can not only absorb ultraviolet rays, but also emit and scatter ultraviolet rays, so it has strong anti-ultraviolet ability. Compared with the same dose of organic anti-ultraviolet agent, its absorption peak in the ultraviolet region is higher; Moreover, nano-titanium dioxide has a blocking effect on the ultraviolet radiation in the medium and long wave regions, unlike organic anti-ultraviolet agents, which only have a shielding effect on the ultraviolet radiation in the medium and long wave regions. Especially because of its fine particles, high transparency of the finished product, and its ability to penetrate visible light, the skin whiteness is natural when it is added to cosmetics, which overcomes the shortcomings of some organic substances or pigment grade titanium dioxide opacity, making the skin appear unnatural pale. Because of this, nano-titanium dioxide was soon widely recognized and gradually replaced some organic anti-ultraviolet agents, becoming a physical shielding anti-ultraviolet agent with superior performance in today’s sunscreen cosmetics.

With the improvement of people’s living standards and the intensification of international competition, the research and development of safe and efficient sunscreen cosmetics will gradually increase. Nowadays, the sunscreen cosmetics market in developed countries has shown strong vitality.

From the perspective of the development trend of sunscreen cosmetics, the first is inorganic sunscreen instead of organic sunscreen, and the second is bionic sunscreen. The latter is expensive and difficult to promote nowadays. The former is generally favored because of its moderate price and superior sunscreen performance. Especially nanometer titanium dioxide has good development momentum and market potential due to its superior performance and application prospects.

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