Journal article
Combined factors influencing the aggregation and deposition of nano-TiO2 in the presence of humic acid and bacteria
Environmental science & technology, Vol.46(13), pp.6968-6976
07/03/2012
DOI: 10.1021/es2034747
PMID: 22455349
Abstract
This study investigates the contributions of natural organic matter (NOM) and bacteria to the aggregation and deposition of TiO(2) 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 Ca(2+)), 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. Ca(2+) 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.
Details
- Title: Subtitle
- Combined factors influencing the aggregation and deposition of nano-TiO2 in the presence of humic acid and bacteria
- Creators
- Indranil Chowdhury - Department of Chemical & Environmental Engineering, University of California, Riverside, California 92521, United StatesDavid M CwiertnySharon L Walker
- Resource Type
- Journal article
- Publication Details
- Environmental science & technology, Vol.46(13), pp.6968-6976
- Publisher
- United States
- DOI
- 10.1021/es2034747
- PMID
- 22455349
- ISSN
- 0013-936X
- eISSN
- 1520-5851
- Language
- English
- Date published
- 07/03/2012
- Academic Unit
- Center for Health Effects of Environmental Contamination; Civil and Environmental Engineering; Public Policy Center (Archive); Chemical and Biochemical Engineering
- Record Identifier
- 9983991952202771
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