Titanium dioxide (TiO2) is also known as Titania or titanium (IV) oxide. Basically, it is a naturally occurring oxide of titanium, has the formula TiO2, and belongs to the transition metal oxide family. There are seven crystalline forms of the naturally occurring white, opaque mineral titanium dioxide; the most important of these are rutile, anatase, and brookite. These oxide types exist naturally and can be easily mined for commercial titanium. Titanium dioxide is absorptive as well as odourless. Commonly found in ores, native dust, sands, and soils, it spontaneously combines with oxygen to generate titanium oxides. Animals and plants frequently contain the element titanium. TiO2 is regarded as a “natural” substance and has been deemed biologically inert in both people and animals, which at least partly explains why the general public has a generally positive opinion of it.
Actually, for almost a century, the majority of TiO2 has been produced from the mineral illmenite, FeTiO3, via the “sulphate” or “chloride” method. Titanium dioxide, an inorganic white chemical, has found widespread use in various products during the past hundred years. UV rays can be both scattered and absorbed by this pigment, which is the whitest and brightest known to exist. It also has reflective properties. It is trusted for its luminous, non-reactive, and non-toxic qualities, which safely raise the whiteness and brightness of numerous materials. An estimate of 5 million tons of titania powder were produced globally in 2005, raising the question of how abundant the material is in the environment. There has been an exponential increase in the amount of nano-sized titania over the previous ten years, with estimates putting it at roughly 2.5% in 2009 and 10% in 2015.
Physical properties
Due to its extreme melting and boiling temperatures of 1843ºC and 2972ºC, it exists naturally as a solid and is insoluble in water, even in particle form.
TiO2 is UV light-absorbing. Unlike other white materials that may appear slightly yellow in certain lighting conditions, this characteristic gives it a dazzling white appearance.
Remarkably, TiO2 has an even greater refractive index than diamond. Because of this, it is a very brilliant material that is ideal to employ in aesthetic design.
The ability of TiO2 to exhibit photocatalytic activity in the presence of UV light is another essential feature. This makes it useful for sterilization, anti-fogging surfaces, environmental purification, various protective coatings, and even cancer treatment.
TiO2 is an insulator as well.
Brilliant
Unique properties like as opacity, pearlescence, color intensity, and brilliance.
Resistant
Paint and film deterioration as well as plastic embrittlement are avoided by materials that are resistant to heat, light, and weathering.
Protective
TiO2 is an essential component of sunscreen because of its capacity to both deflect and absorb UV radiation, shielding the skin from dangerous UV rays that can cause cancer.
Powerful
It is a substance that can lower air pollution and employed as a photo-catalyst in solar panels.
Chemical properties
Powder TiO2 is white, amorphous, tasteless, odourless, and non-hygroscopic. While commercially available titanium dioxide often exists as a pile of particles with a diameter of about 100 mm, powdered titanium dioxide has particles that are typically less than one millimeter. Three crystal forms of the naturally occurring dioxide are rutile, brookite, and anatase. In contrast, the most prevalent kind, rutile, has an octahedral structure. Each titanium atom in anatase and brookite is surrounded by an extremely deformed octahedron of oxygen atoms. Two oxygen atoms are located closer to titanium in these distorted octahedral structures than the other four oxygen atoms. The stability of anatase is around 8–12 kJ/mol higher than that of rutile. The compound has a density of 4.23 g/cm3, a Mohs hardness of 5.8 g/cm3 for anatase and brookite and 6.2 g/cm3 for rutile, a refractive index of 2.488 for anatase, 2.583 for brookite, and 2.609 for rutile, a melting point of 1,843 °C, and it dissolves in concentrated acids but not in water or acids at a lower concentration.
Uses
Pure titanium dioxide, a fine white powder, is utilized to make the brilliant white pigment. It has been applied to many commercial and industrial products for hundreds of years, including adhesives, coated textiles, paints, printing inks, and textile paints. It has also been used in ceramics, floor coverings, roofing materials, pharmaceuticals, food colouring, sunscreen, toothpaste, soap, water treatment agents, vehicle parts, and catalysts. Producing titanium dioxide can be done in two primary ways.
Pigment grade titanium dioxide makes up more than 98% of the overall production, making it the primary form. In applications where white opacity and brightness are required, pigmentary titanium dioxide utilizes its superior light-scattering capabilities. Titanium dioxide can also be produced as an ultrafine (nanomaterial) product. When distinct qualities are needed, including transparency and maximal absorption of UV rays, this shape is used, like in the case of cosmetic sunscreens.
Pigment-grade Titania
Pigment-grade dioxide of titanium is used in many applications where high opacity and brightness are necessary. In actuality, most white, pastel, and even dark colored surfaces and objects contain titanium dioxide. Applications for this include the following:
Paints and Coatings: Titania contributes to paint longevity and painted surface protection by offering opacity and durability.
Rubber, Plastics, and Adhesives: prevents plastics and other materials from becoming brittle, faded, and cracked due to prolonged exposure to light.
Cosmetics: A number of cosmetics use pigment-grade titania to help hide skin discoloration and enhance skin tone. On top of that, it lets you use less heavy makeup to have the same effect.
Paper: Titanium dioxide is applied to paper in order to make it appear whiter, brighter, and more impenetrable.
Materials and Ingredients in Contact with Food: Foods, drinks, supplements, and medications are shielded from early deterioration by titanium dioxide’s opacity to visible and ultraviolet light, which prolongs the shelf life of the product. Additionally, certain classes of prime quality pigment- grade titania are employed as a decorative element in some meals, as well as in medication tablets and capsule coatings.
Nanoscale, or ultrafine-grade, titania
Titanium dioxide ultrafine grades are most frequently employed in the following specialized applications:
Sunscreen: It absorbs UV rays effectively and turns transparent to visible light. The translucent screen that nano-titanium dioxide develops protects the skin from sunlight’s damaging rays owing to its tiny particle size, which absorbs UV light rather than reflecting visible light. The Skin Cancer Foundation states that employing sunscreens containing titanium dioxide possess the potential to prevent skin cancer.
Catalysts: Titanium dioxide serves as a supportive compound in applications involving catalysts. Major applications include the removal of dangerous exhaust gas emissions from automobiles and the removal of nitrous oxides from power plants.