Titanium Dioxide

Titanium dioxide is an oxide of titanium metal and is an inorganic compound. The titanium dioxide formula is TiO2. It is made up of two atoms of oxygen and one atom of titanium which is the 9th most common element in the crust of the earth and it is present generally in plants and animals. In order to form titanium dioxide, the metal of titanium reacts naturally with oxygen. This oxide is commonly found in sands, soils, ores, indigenous, and dust.

It is also referred to as titanium(IV) oxide. The titanium dioxide colour is white, insoluble in water but sometimes the mineral forms of this solid can appear black. It is used for a variety of purposes such as in paints, food colouring, and sunscreen. Titanium dioxide properties make it usable for different industries such as food industries, cosmetic industries, etc. 

Structure of Titanium Dioxide

Titanium exhibits octahedral geometry in all three of its main dioxides. The geometry of the rutile type of titanium dioxide is distorted hexagonal on the other side two different types of TiO2 i.e. anatase and brookite are cubic. The structure of rutile is a general pattern that is being adopted by other difluorides and dioxides of metals e.g. RuO2 and ZnF2.

The structure of molten titanium dioxide is local where each titanium (Ti) is coordinated to around five atoms of oxygen on average. 

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The Production Process of Titanium Dioxide

Some of the production processes of titanium dioxide are given below

• Chloride process

In the chloride process, the ore from which titanium dioxide is prepared is treated with Cl and C to obtain titanium tetrachloride which is a volatile liquid that is later purified through the distillation method. To produce titanium oxide and regenerate chlorine in this process, the TiCl4 is treated with oxygen.

• Sulphate process

Ilmenite is treated with sulphuric acid in the sulphate process to extract iron(II) sulphate pentahydrate. This process is used for the preparation of titanium dioxide.

• Specialized methods

By many specialized chemistries, films of TiO2 are prepared. These are used for different speciality purposes. Sol-gel routes engage in the hydrolysis of titanium alkoxides, such as titanium ethoxide. The reaction is given below.

Ti(OEt)4 + 2H2O → TiO2 + 4EtOH

For the preparation of films, this technology is suitable. The alkoxide is volatilized in this application and then decomposed on contact with a hot surface. The reaction is as follows.

Ti(OEt)4 → TiO2 + 2Et2O

Titanium Dioxide Uses

Some of the titanium dioxides use of pigment-grade titanium dioxide and ultrafine-grade, or nanoscale titanium dioxide are mentioned below.

1. Pigment-grade Titanium Dioxide

Pigment-grade type of titanium dioxide or titanium dioxide pigment is used in a wide range of uses that need high opacity and brightness. In fact, most surfaces and items that are coloured in white, pastel, and dark shades contain this oxide. The applications of pigment-grade titanium dioxide are given below in detail.

• Paints and Coatings: It is used for the purpose of coating in the paint industry because its properties of opacity and durability of titanium dioxide help to ensure the longevity of the paint and protection of the surfaces which are painted.  

• Plastics, Adhesives, and Rubber: Titanium dioxide is helpful to reduce cracking, fading and the brittleness occurring in plastics and other materials as a result of exposure to light.

• Cosmetics: In some cosmetic products pigment-grade titanium dioxide is used to help in order to hide blemishes and brighten the skin. For having the same effect it is used in the thinner coatings of make-up material.

• Paper: Titanium dioxide (TiO2) is used in the paper industry for coating paper, brighter, making it whiter and more opaque.

• Food Materials and Medicinal uses: The opacity to visible and ultraviolet light offered by titanium dioxide protects products of food items, beverages, supplements and pharmaceuticals from degradation in premature periods and enhances the longevity of the product. Titanium dioxide in medicine is continuously used by pharmaceuticals in the form of titanium dioxide tablets. This type of titanium oxide is used in titanium dioxide IP tablets, uses capsule coatings and as a decorative aid in some foods.

2. Ultrafine-grade or Nanoscale Titanium Dioxide

The following are the applications of ultrafine-grades of titanium dioxide:  

• Sunscreen: When nanosized titanium dioxide or ultrafine titanium dioxide comes in contact with sunlight it becomes transparent to visible light and serves as an efficient Ultraviolet absorber of light. Nano-titanium dioxide does not reflect visible light as the size of the particle is very small but does absorb UV light and enables a transparent barrier that protects the skin from the harmful rays of the sun. Titanium dioxide side effects occur when used in an excessive amount on the skin so used while taking precautionary measurements.

• Catalysts: This type of titanium oxide also works as a supporting material for the applications of catalysts. Other major uses are the removal of harmful exhaust gas emissions in the automotive industry and the removal of nitrous oxides in power stations.

Titanium Facts

• The body of human beings rarely rejects titanium metal hence it is sometimes used in medical implants. 

• Titanium (Ti) is twice strong as aluminum (Al) metal. For the usage of high-stress, there used to be a requirement of a strong metal at those places titanium metal is very useful. 

Conclusion