Titanium dioxide is a common additive in many food, personal care, and other consumer products used by people, which after use can enter the sewage system and, subsequently, enter the environment as treated effluent discharged to surface waters or biosolids applied to agricultural land, incinerated wastes, or landfill solids. This study quantifies the amount of titanium in common food products, derives estimates of human exposure to dietary (nano-) TiO(2), and discusses the impact of the nanoscale fraction of TiO(2) entering the environment. The foods with the highest content of TiO(2) included candies, sweets, and chewing gums. Among personal care products, toothpastes and select sunscreens contained 1% to >10% titanium by weight. While some other cremes contained titanium, despite being colored white, most shampoos, deodorants, and shaving creams contained the lowest levels of titanium (<0.01 μg/mg). For several high-consumption pharmaceuticals, the titanium content ranged from below the instrument detection limit (0.0001 μg Ti/mg) to a high of 0.014 μg Ti/mg. Electron microscopy and stability testing of food-grade TiO(2) (E171) suggests that approximately 36% of the particles are less than 100 nm in at least one dimension and that it readily disperses in water as fairly stable colloids. However, filtration of water solubilized consumer products and personal care products indicated that less than 5% of the titanium was able to pass through 0.45 or 0.7 μm pores. Two white paints contained 110 μg Ti/mg while three sealants (i.e., prime coat paint) contained less titanium (25 to 40 μg Ti/mg). This research showed that, while many white-colored products contained titanium, it was not a prerequisite. Although several of these product classes contained low amounts of titanium, their widespread use and disposal down the drain and eventually to wastewater treatment plants (WWTPs) deserves attention. A Monte Carlo human exposure analysis to TiO(2) through foods identified children as having the highest exposures because TiO(2) content of sweets is higher than other food products and that a typical exposure for a US adult may be on the order of 1 mg Ti per kilogram body weight per day. Thus, because of the millions of tons of titanium-based white pigment used annually, testing should focus on food-grade TiO(2) (E171) rather than that adopted in many environmental health and safety tests (i.e., P25), which is used in much lower amounts in products less likely to enter the environment (e.g., catalyst supports, photocatalytic coatings).

Titanium Dioxide Nanoparticles in Food and Personal Care Products

Nitrogen-doped titanium dioxide as visible-light-sensitive photocatalyst: designs, developments, and prospects.

https://opus.lib.uts.edu.au/bitstream/10453/43832/3/MED%2027143286%20am.pdf

Progress in the biological and chemical treatment technologies for emerging contaminant removal from wastewater: A critical review.

Although mesoporous materials have well-defined pore structures, these fine materials can surprisingly be produced by employing a set of conventional and simple procedures such as mixing, heating, filtration, and washing, using low-cost materials. They can be regarded as easy-to-make bulk nanostructured materials. Mesoporous materials have great potential for use in both macroscopic applications and nanotechnology. In this account, we introduce examples of recent developments in mesoporous materials involving innovations in their components and structural designs and concentrating on our own recent progress. These examples include syntheses of mesoporous silica, metal oxides, semiconductive materials, metals, alloys, organic composites, biomaterial composites, carbon, carbon nitride, and boron nitride, as innovative components. As structural innovations for mesoporous materials, various film preparations, pore alignments, and hierarchic structures are described together with their related functions including sensing and controlled release of target molecules.

Nanoarchitectonics for mesoporous materials

In heterogeneous single-metal-site catalysts (HSMSCs) the active metal centres are located individually on a support and are stabilized by neighbouring surface atoms such as nitrogen, oxygen or sulfur. Modern characterization techniques allow the identification of these individual metal atoms on a given support, and the resulting materials are often referred as single-atom catalysts. Their electronic properties and catalytic activity are tuned by the interaction between the central metal and the neighbouring surface atoms, and their atomically dispersed nature allows for metal utilization of up to 100%. In this way, HSMSCs provide new opportunities for catalysis, and with respect to structure build a bridge between homogeneous and heterogeneous catalysis. Herein, selected publications from 2010 in this area are reviewed and their perspectives for the near future are highlighted. Where appropriate, comparisons between HSMSCs and homogeneous/heterogeneous counterparts are presented. Single-atom catalysts have drawn increasing attention as methods for their preparation and characterization improve. Here, Beller and co-workers discuss the latest developments in the field of single-metal-site catalysts, discussing how this catalyst class bridges heterogeneous and homogeneous catalysis, and providing a perspective on how the field might continue to develop.

Bridging homogeneous and heterogeneous catalysis by heterogeneous single-metal-site catalysts

TiO2, ZnO2, and CrO2 nanoparticles were prepared by novel quick precipitation method, where transition metal oxides were used as catalyst. All nanoparticles were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The average particle size for TiO2, ZnO2, and CrO2 was 44.8, 13.4, and 77.6 nm, respectively. Catalytic properties of these nanomaterials were studied using ammonium perchlorate (AP)/hydroxy-terminated polybutadiene (HTPB) propellant by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Both experimental results reveal that there is an increase in the thermal decomposition of propellants in the presence of transition metal oxide nanoparticles. Activation energy of high-temperature decomposition (HTD) of propellant with transition metal oxide nanoparticles was calculated by Kissinger equation. Burning rates of propellants were also calculated.

Transition metal oxide nanoparticles: Potential nano-modifier for rocket propellants

Nano-crystalline copper ferrite (CuFe2O4) was prepared by co-precipitation method and physicochemically characterized by a few techniques such as powder X-ray diffraction (XRD), Raman, and Ultraviolet-visible spectroscopy. Its catalytic effect was...

/pdf/effect-of-copper-ferrite-cufe2o4-in-the-thermal-bf1ngcqh.pdf

Effect of Copper ferrite CuFe2O4 in the thermal decomposition of modified Nitrotriazolone

Nanotechnology is the art and science of manipulating matter at the nanoscale (down to 1/100,000 the width of a human hair) to create new and unique materials and products. Nanotechnology has enormous potential to change society. An estimated global research and development investment of nearly $9 billion per year is anticipated to lead to new medical treatments and tools; more efficient energy production, storage and transmission; better access to clean water; more effective pollution reduction and prevention; and stronger, lighter materials. And these are just a few of the more significant ways in which people are discussing using the technology. In this chapter we discussing about emerging application of nanoscience.

Emerging Applications of Nanoscience

https://link.springer.com/content/pdf/10.1007/s11664-021-09335-3.pdf

Effect of Nanosize Zinc Ferrite on Thermolysis of Ammonium Perchlorate

Ferrites especially transition metal based catalysts show a versatile catalytic ability for thermal decomposition of solid propellants. Herein, XRD, UV-visible spectroscopy, Raman spectroscopy, and N2-adsorption desorption analyses were used to analysis trimetallic nano-ferrite NiCuZnFe2O4 synthesized by co-precipitation method. The particle size of the NiCuZnFe2O4 found between 9–20 nm. Moreover, we have studied catalytic activity of tri metal ferrite (NiCuZnFe2O4) on thermal decomposition of propellant oxidizer ammonium perchlorate (AP) and monitored by simultaneous thermal analyses. The increased surface area, smaller band gap, and crystalline Raman phase of the AP + NiCuZnFe2O4 mixture contributed to substantial physico-chemical and catalytic outcomes. The combination of AP with the nano-catalyst NiCuZnFe2O4 reduced ignition delay, which was ascribed to a lower thermal decomposition temperature. 

Shalini Chaturvedi

Papers

Transition metal oxide nanoparticles: Potential nano-modifier for rocket propellants

Effect of Copper ferrite CuFe2O4 in the thermal decomposition of modified Nitrotriazolone

Emerging Applications of Nanoscience

Effect of Nanosize Zinc Ferrite on Thermolysis of Ammonium Perchlorate

Nano Size NiCuZnFe 2 O 4 Tri Metal Spinel Ferrite: Synthesis, Characterizations and Additive for Thermolysis of Ammonium Perchlorate