From dyes to flavorings, many people are becoming increasingly aware of the ingredients in their food.

What's the Verdict?

There is also some evidence to suggest that exposure to titanium dioxide nanoparticles may be harmful or toxic to the environment, including aquatic life and other organisms. The production and disposal of the mineral may also release pollutants, such as carbon dioxide and sulfur dioxide, into the air and water.

The Scientific Committee on Consumer Safety issued an opinion of the safety of titanium dioxide in food, stating that it should no longer be considered as safe when used as a food additive.

The basic scenario of resistive switching in TiO₂ (Jameson et al., 2007) assumes the formation and electromigration of oxygen vacancies between the electrodes (Baiatu et al., 1990), so that the distribution of concomitant n-type conductivity (Janotti et al., 2010) across the volume can eventually be controlled by an external electric bias, as schematically shown in Figure 1B. Direct observations with transmission electron microscopy (TEM) revealed more complex electroforming processes in TiO₂ thin films. In one of the studies, a continuous Pt filament between the electrodes was observed in a planar Pt/TiO₂/Pt memristor (Jang et al., 2016). As illustrated in Figure 1C, the corresponding switching mechanism was suggested as the formation of a conductive nanofilament with a high concentration of ionized oxygen vacancies and correspondingly reduced Ti³⁺ ions. These ions induce detachment and migration of Pt atoms from the electrode via strong metal–support interactions (Tauster, 1987). Another TEM investigation of a conductive TiO₂ nanofilament revealed it to be a Magnéli phase Ti_nO_2n−1 (Kwon et al., 2010). Supposedly, its formation results from an increase in the concentrations of oxygen vacancies within a local nanoregion above their thermodynamically stable limit. This scenario is schematically shown in Figure 1D. Other hypothesized point defect mechanisms involve a contribution of cation and anion interstitials, although their behavior has been studied more in tantalum oxide (Wedig et al., 2015; Kumar et al., 2016). The plausible origins and mechanisms of memristive switching have been comprehensively reviewed in topical publications devoted to metal oxide memristors (Yang et al., 2008; Waser et al., 2009; Ielmini, 2016) as well as TiO₂ (Jeong et al., 2011; Szot et al., 2011; Acharyya et al., 2014). The resistive switching mechanisms in memristive materials are regularly revisited and updated in the themed review publications (Sun et al., 2019; Wang et al., 2020).

The Scientific Committee on Consumer Safety issued an opinion of the safety of titanium dioxide in food, stating that it should no longer be considered as safe when used as a food additive.

Les pouvoirs couvrant et éclaircissant du lithopone normal sont supérieurs à ceux de la céruse et de l'oxyde de zinc, mais inférieurs au Dioxyde de Titane pur, étant le meilleur blanc sous tout rapport. C'est le sulfure de zinc qui, avec son indice de réfraction de 2,37, est l’élément opaque ; le 2nd composé, le sulfate de baryum, joue un rôle de diluant minéral et favorise l'efficacité de la diffusion du premier.

Titanium dioxide can be both safe and unsafe, depending on its use. When inhaled, titanium dioxide is considered possibly carcinogenic to humans. This means that in products that contain powdered titanium dioxide like loose powders, pressed powders, eyeshadows, and blushes in which the makeup is in powder form, titanium dioxide can be inhaled. Titanium dioxide is also an occupational chemical of concern, as workers might inhale titanium dioxide when manufacturing products.

Why does the exposure route matter, and what's the risk? 

The applications in which it can be used are paints, inks, plastics, elastomers, paper, fillers, adhesives… 

Procurement Resource provides latest prices of Titanium Dioxide. Each price database is tied to a user-friendly graphing tool dating back to 2014, which provides a range of functionalities: configuration of price series over user defined time period; comparison of product movements across countries; customisation of price currencies and unit; extraction of price data as excel files to be used offline.