报告题目：食品级二氧化硅纳米材料的表征、宿命和影响：生命周期视角(Characterization, Fate, and Impacts of Food-Grade Silicon Dioxide Nanomaterials: A Life Cycle Perspective)

报告人：杨宇 博士（North American Hoganas）

时间：2016年7月4日 16:30

地点：校本部东区环化楼401会议室

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ABSTRACT
Government, industry, and academic institutions are increasing focus on transformations and reactions of nanomaterials across their value chain, from the point of synthesis through use phases and into the environment, yet few examples quantitatively assess nanomaterials across their life cycle. Using a life cycle perspective, we examined food-grade silicon dioxide nanomaterial (nano SiO2) across its value chain in the food supply. We selected SiO2 because it has recent controversial adverse health outcome potential with little known environmental fate, is produced in a high volume, and is widely exposed to humans. Understanding transformations in nanomaterials from food-grade raw material through use and into end-of-life is not trivial. Whereas thousands of food products may contain nano SiO2, we benefited by moving up the value chain to procure pure food-grade SiO2 stocks. The stocks were all amorphous nanomaterials with primary particle size in the range of 9–26 nm and demonstrated high consistency in size, morphology, and composition. This knowledge allowed us to identify and confirm that 10 out of 14 food products contained amorphous nano SiO2. The dissolution potential study of food-grade SiO2 showed that as high as 6.8% (by weight) of dissolution can occur while un-dissolved SiO2 maintained the same morphology as the food-grade SiO2 stocks in the complex food matrices. This knowledge enabled relevant biological testing on the food-grade SiO2 that showed adverse impacts in the digestive tract (i.e., microvilli) at 1 mg SiO2/L. The association of nano SiO2 with microvilli was not a unique biological interaction as we also observed accumulation of amorphous nano SiO2 on bioflocs in tests using lab-cultured activated sludge and sewage sludges from a full-scale wastewater treatment plant. Overall, despite the reputation of food-grade nano SiO2 as being chemically inert and biologically benign, we provide evidence to the contrary.

报告人简介：
杨宇(Ph.D., PE): 注册土木工程师。目前在North American Hoganas 担任水处理工程师，负责饮用水和废水处理的新材料研发，电絮凝去除重金属，以及其它水处理技术的优化。2015 年在 Marquette University 做博士后，研究转基因 E.coli的蛋白调控用于磷回收。2012-2014 在Arizona State University做了2年博士后，主要研究纳米材料的环境影响,纳米颗粒在环境中的监测和迁移转化。2012 年在 University of Missouri博士毕业，博士研究方向是金属纳米颗粒对于厌氧消化过程的影响。2008 年从中国科学院生态环境研究中心硕士毕业。2005年从哈尔滨工业大学环境工程系本科毕业。到目前为止,已在Environmental Science and Technology, Water Research, Science of the Total Environment 等期刊发表文章 27 篇 (一篇Book Chapter)。作为审稿人为18种 期刊审稿50余次。也曾担任过Poland National Science Foundation (NSF), Canada Natural Sciences and Engineering Research Council和 US NSF Graduate Research Fellowships Program (GRFP)的评审。作为Co-PI 和Significant contributor 成功申请过3个Funding (包括一个美国NSF Career)。