2. Particle Size The application often dictates the required particle size. Suppliers typically offer various grades of barium sulphate, categorized by their particle size distribution. For example, finer particle sizes are often favored in cosmetic applications, while coarser grades may be used in construction materials.

The FDA first approved the use of titanium dioxide in food in 1966, following its 1960 removal (along with the removal of other color additives) from the agency's original Generally Recognized as Safe list. In 1977, titanium dioxide joined the list of color additives that are exempt from certification, which means titanium dioxide doesn't have to be listed on the packaging of every product it's used in, Faber noted.

Lithopone, C.I. Pigment White 5, is a mixture of inorganic compounds, widely used as a white pigment powder. It is composed of a mixture of barium sulfate and zinc sulfide. These insoluble compounds blend well with organic compounds and confer opacity. It was made popular by the cheap production costs, greater coverage. Related white pigments include titanium dioxide, zinc oxide (zinc white), zinc sulfide, and white lead.^[1]

However, the use of titanium dioxide has also raised concerns about its potential impact on human health and the environment. Some studies have suggested that titanium dioxide nanoparticles may have harmful effects when inhaled or ingested. Manufacturers of titanium dioxide are therefore taking steps to minimize the risk of exposure and develop safer products.

Production

Fig. 4. Hemolysis (%) values of samples, A: 0.2 mg/mL P25TiO₂NPs; B: 0.02 mg/mL P25TiO₂NPs; C: 0.2 mg/mL VitaminB2@P25TiO₂NPs; D: 0.02 mg/mL VitaminB2@P25TiO₂NPs after 3 h of irradiation (red) and 6 h (blue). SD <5 for all samples and p <0.05 between C-D and A-B.