When E171 isn’t combined with other ingredients and administered in water, some studies suggest that under these artificial conditions, E171 may be processed differently in the body resulting in some biological changes in experimental animals that are poorly understood.

Some websites maintain titanium dioxide is inferior to zinc oxide, another mineral sunscreen ingredient whose core characteristics are similar to those of titanium dioxide. The reality is that titanium dioxide is a great broad-spectrum SPF ingredient and is widely used in all manner of sun-protection products. What gets confusing for some consumers is trying to decipher research that ranks sunscreen ingredients by a UV spectrum graph. By most standards, broad-spectrum coverage for sunscreen ingredients is defined as one that surpasses 360 nanometers (abbreviated as “nm” - how the sun’s rays are measured). Titanium dioxide exceeds this range of protection, but depending on whose research you read, it either performs as well as or slightly below zinc oxide.

As a widely used substance with multiple applications, research is being carried out to improve the production process to reduce the levels of chemicals used and waste produced, and to recycle any by-products.

Titanium dioxide nanoparticles have also been found in human placentae and in infant meconium, indicating its ability to be transferred from mother to fetus. 

2: Clarification mechanism of coagulant

Chemical coagulation is a process in which chemical agents (coagulants) are added to water treatment to make colloidal dispersion system destabilize and agglomerate. In the coagulation process, small suspended particles and colloidal impurities are aggregated into larger solid particles to separate particulate impurities from water, which is called coagulation clarification.

After adding coagulant into water, colloidal particles and other small particles can be polymerized into larger flocs through the comprehensive action of mixing, coagulation and flocculation. The whole process of coagulation and flocculation is called coagulation.

(1) Destabilization and condensation of colloids

Adding electrolyte to water can compress the electric double layer and destabilize the colloid. The main mechanism is that the electric double layer of colloidal particles in water is compressed or neutralized by adding aluminum salt or iron salt coagulant. The coagulant and raw water are mixed rapidly and evenly, and a series of chemical reactions are produced to destabilize. This process takes a short time, generally about 1 min. Some cationic polymers can also play a role in the destabilization and condensation of colloids in water. These polymers have a long chain structure and positive charge in water. Their destabilization and condensation of colloids in water is due to the interaction of van der Waals force adsorption and electrostatic attraction.

(2) Flocculation and formation of floc (alum)

The particle size of the initial flocculate formed by colloid destabilization and coagulation in water is generally more than 1 m. at this time, Brownian motion can no longer push them to collide and form larger particles. In order to make the initial flocs collide with each other to form large flocs, it is necessary to input additional energy into the water to produce a velocity gradient. Sometimes it is necessary to add organic polymer flocculant into water, and the adsorption bridging effect of long chain molecules of flocculant is used to improve the probability of collision and adhesion. Flocculation efficiency usually increases with the increase of flocculate concentration and flocculation time.

Compared with polyaluminum chloride, polyaluminum chloride has the advantages of high density, fast settling speed and wide pH adaptability; the coagulation effect is less affected by temperature than that of polyaluminum sulfate; however, when adding ferric salt, it should be noted that when the equipment is not in normal operation, the iron ions will make the effluent color, and may pollute the subsequent desalination equipment.

Different dermal cell types have been reported to differ in their sensitivity to nano-sized TiO₂ . Kiss et al. exposed human keratinocytes (HaCaT), human dermal fibroblast cells, sebaceous gland cells (SZ95) and primary human melanocytes to 9 nm-sized TiO₂ particles at concentrations from 0.15 to 15 μg/cm² for up to 4 days. The particles were detected in the cytoplasm and perinuclear region in fibroblasts and melanocytes, but not in kerati-nocytes or sebaceous cells. The uptake was associated with an increase in the intracellular Ca²⁺ concentration. A dose- and time-dependent decrease in cell proliferation was evident in all cell types, whereas in fibroblasts an increase in cell death via apoptosis has also been observed. Anatase TiO₂ in 20–100 nm-sized form has been shown to be cytotoxic in mouse L929 fibroblasts. The decrease in cell viability was associated with an increase in the production of ROS and the depletion of glutathione. The particles were internalized and detected within lysosomes. In human keratinocytes exposed for 24 h to non-illuminated, 7 nm-sized anatase TiO_2, a cluster analysis of the gene expression revealed that genes involved in the “inflammatory response” and “cell adhesion”, but not those involved in “oxidative stress” and “apoptosis”, were up-regulated. The results suggest that non-illuminated TiO₂ particles have no significant impact on ROS-associated oxidative damage, but affect the cell-matrix adhesion in keratinocytes in extracellular matrix remodelling. In human keratinocytes, Kocbek et al. investigated the adverse effects of 25 nm-sized anatase TiO₂ (5 and 10 μg/ml) after 3 months of exposure and found no changes in the cell growth and morphology, mitochondrial function and cell cycle distribution. The only change was a larger number of nanotubular intracellular connections in TiO₂-exposed cells compared to non-exposed cells. Although the authors proposed that this change may indicate a cellular transformation, the significance of this finding is not clear. On the other hand, Dunford et al. studied the genotoxicity of UV-irradiated TiO₂ extracted from sunscreen lotions, and reported severe damage to plasmid and nuclear DNA in human fibroblasts. Manitol (antioxidant) prevented DNA damage, implying that the genotoxicity was mediated by ROS.

In addition to quality, CAS 13463-67-7 also places a strong emphasis on sustainability. The factory is dedicated to reducing its environmental impact by implementing eco-friendly practices and technologies. From waste reduction to energy efficiency, CAS 13463-67-7 is constantly looking for ways to improve its sustainability and contribute to a greener future.

Stability and darkening:

2.Inorganic white pigment. Widely used as a white pigment for plastics, paints and inks such as polyolefins, vinyl resins, ABS resins, polystyrene, polycarbonate, nylon and polyoxymethylene.

Recent analyses of food-grade TiO₂ samples have found that a significant portion of particles may be within the nanoscale. These particles (also known as nanoparticles) range in size from 1 to 100 nm, where 1 nm equals 1 billionth of a metre (the width of a typical human hair is 80,000 to 100,000 nm).

Titanium dioxide, or TiO2, sometimes referred to as E171, is an inorganic, solid substance used in a wide range of consumer goods including cosmetics, paint, plastic and food, according to the American Chemistry Council.

CSPI’s Chemical Cuisine is the web’s definitive rating of the chemicals used to preserve foods and affect their taste, texture, or appearance. Besides titanium dioxide, the group recommends avoiding artificial sweeteners like aspartame, acesulfame potassium, and sucralose, as well as synthetic food dyes like Yellow 5 and Red 3. CSPI and others have recently asked the Food and Drug Administration to ban the latter dye in foods and ingested drugs because the FDA has already determined that it is a carcinogen unsafe for use in cosmetics.

Overall, the Food Directorate's comprehensive review of the available science of TiO₂ as a food additive showed: