barium sulphate medical use

Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.

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In the pigment industry, rutile titanium dioxide is widely used due to its brightness and extremely high refractive index, which provides excellent hiding power in paints, plastics, paper, inks, fibers, and foods. It is the most common white pigment because of its non-toxicity, stability, and ability to reflect all colors of light equally. The use of rutile titanium dioxide in paint formulations ensures long-lasting, vibrant colors that are resistant to fading caused by exposure to sunlight.

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  • However, they did find that minor levels of 0.01% were absorbed by immune cells — known as gut-associated lymphoid tissue — and may be delivered to other organs. Currently, it’s unknown how this may affect human health (17Trusted Source).