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Effects of Humic Acid and Sunlight on the Generation and Aggregation State of Aqu/C60 Nanoparticles
Citation:
Isaacson, C. AND D. BOUCHARD. Effects of Humic Acid and Sunlight on the Generation and Aggregation State of Aqu/C60 Nanoparticles. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 44(23):8971-8976, (2010).
Impact/Purpose:
see description
Description:
Aqueous suspensions of nanoscale C60 aggregates (aqu/C60) were produced by stirring in water with Suwanee River Humic Acid (humic acid) and water from Call’s Creek, a small stream near Athens, GA. Time course experiments were conducted to determine the effects of sunlight and solution chemistry on the mass of aqu/C60 suspended, nanoparticle size, and ζ potential. For all treatments, sunlight had the greatest effect on the mass of aqu/C60 suspended. The sunlight-exposed Call’s Creek samples exhibited the greatest increase in mass suspended with aqu/C60 concentrations 17 times greater than those of the dark controls, followed by the humic acid treatments, 8.1 times, and deionized water, 3.4 times. Asymmetric flow field-flow fractionation indicated that aqu/C60 nanoparticles in humic acid were the smallest and their mass was evenly distributed in the 120−300 nm hydrodynamic diameter (Dh) size range, whereas aqu/C60 nanoparticles in Call’s Creek water were the largest and were evenly distributed in the size range of 200−300 nm Dh. Aqu/C60 in deionized water and humic acid treatments exposed to sunlight exhibited a trend of increasingly negative ζ potentials as suspension time increased; however, this trend was not observed for the Call’s Creek treatment.
