TiO2 nanoparticles are well known for their biocidal properties. Modification of parent TiO2 nanoparticles is done to optimize their photo-efficiency under  solar  or visible illumination. High through put (HTP) assays are being developed to test the effectiveness and environmental risk of these modified materials. A series of TiO2 materials with different crystal phase, size, porosity, and surface area were synthesized by sol-gel methods followed by calcination at temperatures ranging from 100-900 �C. Each material was characterized by conventional microscopy and physicochemical techniques. The materials exhibited several different crystal phases and pore volumes in the range 0.2-0.659 cm3/g, BET surface areas from 0.95 to 482 m2/g and crystal  size from 4.5 to 80 nm.  To understand if the biocidal effectiveness of these materials related to these physicochemical characteristics, a HTP assay was used that featured a gram negative, bioluminescent bacteria (vibrio fischeri). Viability measures of these organisms were collected after a 30 and 60 min exposure to each material (500-2000 �g mL-1). In general,  the anatase crystal phase was consistently more toxic than rutile phase. Linear regression analyses indicated that across all concentrations, toxicity and the individual physical property occurred in the following rank order (highest to lowest):  pore volume>BET area>>crystal size. Such data sets may be helpful in the future design of metal oxides with  more controlled biocidal properties.

Linking the physicochemical properties of modified titania with its biocidal properties

248th National Meeting (2014)

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