COLL 393 |
| Environmental fate of the engineered nanoparticles needs to be studied with great care due to their increasing exposure in the environment. pH dependent sorption of humic acid (HA) on aluminium oxide nanoparticles was studied. Colloidal stability of the nanoparticles was investigated as a function of pH and HA concentrations with dynamic light scattering (DLS) and atomic force microscopy (AFM) measurements. The highest sorption capacity was observed in acidic pH. Aggregation kinetic measurements of the pure nanoparticles indicate colloidal stability in pHs far away from the point of zero charge (ZPC) of the nanoparticles. Aggregation of the nanoparticles is prominent at the pH of ZPC. These results corroborated with the AFM data. Aggregation of the Nano particles is strongly inhibited with the addition of 20 ppm of HA at the pH of the ZPC or above. The aggregation kinetics study of the nanoparticles at pH 4.0 showed increased aggregate size with increasing HA concentration. Therefore, both pH and HA strongly influence the colloidal behavior of the aluminium oxide nanoparticles. |
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The Physical Chemistry of Environmental Interfaces
2:00 PM-6:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 225, Oral
Division of Colloid & Surface Chemistry |