Synthesis and ageing transformations of manufactured metal oxide nanomaterials

• Main Author: Briffa, Sophie Marie
• Published: University of Birmingham 2017
• Subjects: 620.1; GE Environmental Sciences
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715587

With the increased use of manufactured nanomaterials (MNMs) and increased environmental and human exposure, "nanosafety" has become a major research objective. This field has yet to advance due to challenges in systematically linking physicochemical properties to toxicity. The aim of this work was to develop a library of comparable NMs and study their behaviour and ageing in different scenarios. A library of metal oxide NMs based on a PVP capped ceria synthesis protocol was developed and extensively characterised. The protocol was successfully modified to produce PVP capped zinc oxide and copper oxide NMs, of comparable sizes. These NMs along with commercial uncoated ceria NMs were subjected to time and temperature dependent studies. The work studied the transformations occurring on exposure to 25, 45, 65 and 80 °C temperatures for 4 weeks. Results showed increased aggregation, changes in metal valency state and decreased stability with increasing temperature and time. Finally the potential phosphate induced environmental transformation of ceria was studied for the ceria library NMs, the commercial ceria NM and a series of zirconium doped ceria NMs. Samples were exposured to pH-adjusted phosphatisation solutions. Ceria and ceria-rich samples underwent physical and chemical transformations. Furthermore the commercial ceria was exposed to a pH-adjusted phospholipid containing phosphatisation solution where no characteristic phosphate ageing transformations were observed.