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[资源] EST惊现关于食品级二氧化钛的文章！

这是一篇最近（2014年4月）发表在ACS下的EST（环境领域顶级期刊）的一篇关于食品级二氧化钛的文章，主要进行其结构的表征，毒性等研究，并与P25等进行了对比，开拓了纳米材料在食品方面运用的新领域，非常有意思，推荐一下，其摘要如下：
Titanium dioxide (TiO2) is widely used in food products, which will eventually enter wastewater treatment plants and terrestrial or aquatic environments, yet little is known about the fraction of this TiO2 that is nanoscale, or the physical and chemical properties of TiO2 that inﬂuence its human and environmental fate or toxicity. Instead of analyzing TiO2 properties in complex food or environmental samples, we procured samples of food-grade TiO2 obtained from global food suppliers and then, using spectroscopic and other analytical techniques, quantiﬁed several parameters (elemental composition, crystal structure, size, and surface composition) that are reported to inﬂuence environmental fate and toxicity. Another sample of nano-TiO2 that is generally sold for catalytic applications (P25) and widely used in toxicity studies, was analyzed for comparison. Food-grade and P25 TiO2 are engineered products, frequently synthesized from puriﬁed titanium precursors, and not milled from bulk scale minerals. Nanosized materials were present in all of the food-grade TiO2 samples, and transmission electron microscopyshowed that samples 1−5 contained 35, 23, 21, 17, and 19% of nanosized primary particles (<100 nm in diameter) by number, respectively (all primary P25 particles were <100 nm in diameter). Both types of TiO2 aggregated in water with an average hydrodynamic diameter of >100 nm. Food-grade samples contained phosphorus (P), with concentrations ranging from 0.5 to 1.8 mg of P/g of TiO2. The phosphorus content of P25 was below inductively coupled plasma mass spectrometry detection
limits. Presumably because of a P-based coating detected by X-ray photoelectron spectroscopy, the ζ potential of the food-grade TiO2 suspension in deionized water ranged from −10 to −45 mV around pH 7, and the iso-electric point for food-grade TiO2(<pH 4) was signiﬁcantly lower than that for P25. The presence of other elements in or on the TiO2(Si content of 0.026−0.062% and Al content of 0.0006−0.810%) was also diﬀerent from the case for P25 and would inﬂuence the environmental fate of TiO2. X-ray diﬀraction analysis conﬁrmed the presence of anatase and/or rutile in the food-grade materials, and although the presence of amorphous TiO2 could not be ruled out, it is unlikely on the basis of Raman analysis. The food-grade TiO2 was solar photoactive. Cationic dyes adsorbed more readily to food-grade TiO2 than P25, indicating very diﬀerent potentials for interaction with organics in the environment. This research shows that food-grade TiO2 contains engineered nanomaterials with properties quite diﬀerent from those of P25, which has previously been used in many ecotoxicity studies, and because food-grade TiO2 is more likely than P25 to enter the environment (i.e., potentially higher exposure levels), there is a need to design environmental (and human) fate and toxicity studies comparing food-grade to catalytic TiO2.

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附件 1 : 2014_Yang_et_al_Characterization_of_Food-Grade_Titanium_Dioxide__The_Presence.pdf

2014-05-14 14:27:02, 534.75 K