Journal article
Combined Factors Influencing the Aggregation and Deposition of nano-TiO2 in the Presence of Humic Acid and Bacteria
Environmental science & technology, v 46(13), pp 6968-6976
03 Jul 2012
PMID: 22455349
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
This study investigates the contributions of natural organic matter (NOM) and bacteria to the aggregation and deposition of TiO2 nanoparticles (TNPs) in aquatic environments. Transport experiments with TNPs were conducted in a microscopic parallel plate system and a macroscopic packed-bed column using fluorescently tagged E. coli as a model organism and Suwannee River Humic Acid as a representative NOM. Notably, TNPs were labeled with fluorescein isothiocyanate allowing particles and cells to be simultaneously visualized with a fluorescent microscope. Results from both experimental systems revealed that interactions among TNPs, NOM, and bacteria exhibited a significant dependence on solution chemistry (pH 5 and 7) and ion valence (K+ and Ca2+), and that these interactions subsequently affect TNPs deposition. NOM and E. coli significantly reduced deposition of TNPs, with NOM having a greater stabilizing influence than bacteria. Ca2+ ions played a significant role in these interactions, promoting formation of large clusters of TNPs, NOM, and bacteria. TNPs transport in the presence of both NOM and E. coli resulted in much less deposition than in the presence of NOM or E. coli alone, indicating a complex combination of interactions involved in stabilization. Generally, over the aquatic conditions considered, the extent of TNPs deposition follows: without NOM or bacteria > with bacteria only > with NOM only > combined bacteria and NOM. This trend should allow better prediction of the fate of TNPs in complex aquatic systems.
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Details
- Title
- Combined Factors Influencing the Aggregation and Deposition of nano-TiO2 in the Presence of Humic Acid and Bacteria
- Creators
- Indranil Chowdhury - University of California, RiversideDavid M. Cwiertny - University of IowaSharon L. Walker - University of California, Riverside
- Publication Details
- Environmental science & technology, v 46(13), pp 6968-6976
- Publisher
- American Chemical Society; Washington, DC
- Number of pages
- 9
- Grant note
- DBI-0830117 / University of California Center for the Environmental Implications of Nanotechnology (National Science Foundation) DBI-0830117 / University of California Center for the Environmental Implications of Nanotechnology (Environmental Protection Agency)
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- College of Engineering
- Web of Science ID
- WOS:000305876500010
- Scopus ID
- 2-s2.0-84863502215
- Other Identifier
- 991021229984404721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Engineering, Environmental
- Environmental Sciences