In 2019, EFSA published a statement on the review of the risk related to the exposure to food additive titanium dioxide (E171) performed by the French Agency for Food, Environment and Occupational Health Safety (ANSES). In its statement, EFSA highlighted that the ANSES opinion reiterated the uncertainties and data gaps previously identified by EFSA and did not present findings that invalidated the Authority’s previous conclusions on the safety of titanium dioxide.

lithopone supplier is a white pigment (PW5) co-precipitated from solutions of zinc and barium salts according to the following reaction: 

Background and overview

Globally, Iron Oxide is the second largest inorganic pigment after Titanium Dioxide and the first largest color inorganic pigment. Iron oxide pigments mainly include iron oxide red, yellow, black and brown with iron oxide as the basic material. Iron oxide yellow, also known as hydroxyl iron oxide (FeOOH), will be dehydrated and decomposed into red at about 177 ℃, so the application of ordinary iron yellow pigment in high-temperature occasions such as plastic processing and baking coatings is limited. Iron oxide yellow pigment can improve its temperature resistance through surface coating, so as to expand the application field of iron oxide yellow pigment.

The chemical formula of iron oxide yellow (also known as hydroxyl iron) is α- Fe2O3 · H2O or α- FeOOH, with needle like structure and yellow powder, is a kind of particle size less than 0.1 μ m. Iron series pigment with good dispersibility in transparent medium has strong coloring power, high covering power, insoluble in alkali and slightly soluble in ACID. Synthetic iron oxide yellow has the characteristics of light resistance, good dispersion, non-toxic, tasteless and difficult to be absorbed by human body. It is widely used in coatings, plastics, ink and pharmaceutical industry.

Physical and chemical properties and structure

1. Iron oxide yellow pigment has acid and alkali resistance, resistance to general weak and dilute acids, and is very stable in alkaline solution of any concentration.

2. Iron oxide yellow pigment has certain light resistance, heat resistance and weather resistance. Its coating color is durable and can keep the coating from being damaged in light. Iron oxide yellow pigment is stable in a certain temperature range, but beyond the limit temperature, its color begins to change, and the degree of change is more significant with the increase of temperature. Iron oxide yellow pigment is not affected by cold, heat, dry and wet weather conditions.

3. Iron oxide yellow pigment is very stable in any ambient atmosphere (such as gases containing H 2S, Co, so 2, HCl, no, etc.). And resistant to pollution, water, oil and solvent penetration, insoluble in water, mineral oil or vegetable oil.

4. Iron oxide yellow pigment has strong coloring power and high hiding power. With the decrease of pigment particle size, its coloring power is stronger.

application

Nano iron oxide yellow has the characteristics of acid resistance, alkali resistance, non toxicity and low price. It is widely used in coatings, plastics and rubber. The particle size of nano iron yellow is less than 100 nm, which makes it have some unique characteristics. When light shines on its surface, transmission and diffraction will occur, showing transparent yellow, and can strongly absorb ultraviolet rays, Therefore, it can be used as a functional pigment for the surface paint of high-grade cars, precision instruments, bicycles, motorcycles, cosmetics, food, drugs and other coloring additives.

Apart from proximately neuromorphic technologies, TiO₂-based memristors have also found application in various sensors. The principle of memristive sensorics is based on the dependency of the resistive switching on various external stimuli. This includes recording of mechanical energy (Vilmi et al., 2016), hydrogen detection (Hossein-Babaei and Rahbarpour, 2011; Strungaru et al., 2015; Haidry et al., 2017; Vidiš et al., 2019), γ-ray sensing (Abunahla et al., 2016), and various fluidic-based sensors, such as sensors for pH (Hadis et al., 2015a) and glucose concentration (Hadis et al., 2015b). In addition, TiO₂ thin films may generate photoinduced electron–hole pairs, which give rise to UV radiation sensors (Hossein-Babaei et al., 2012). Recently, the biosensing properties of TiO₂-based memristors have been demonstrated in the detection of the bovine serum albumin protein molecule (Sahu and Jammalamadaka, 2019). Furthermore, this work has also demonstrated that the introduction of an additional graphene oxide layer may effectively prevent the growth of multidimensional and random conductive paths, resulting in a lower switching voltage, better endurance, and a higher resistance switching ratio. This opens up a new horizon for further functional convergence of metal oxides and two-dimensional memristive materials and interfaces (Zhang et al., 2019a).