Date of Award

5-2012

Document Type

Thesis

Degree Name

Master of Arts (MA)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Yang Deng

Committee Member

Huan Feng

Committee Member

Shifeng Hou

Abstract

Nanomaterial (NM) based manufacturing is predicted to grow to 15% of the global manufacturing economy by 2014. Subsequent to their use, most of the engineered nanomaterials (ENMs), man-made particles with at least dimension between 1 and 100 nm, will be disposed of in landfills. Landfill leachate is highly contaminated wastewater containing a variety of constituents that may affect the fate and transport of the nanomaterials. In this study, the size and zeta potential of cerium oxide (CeO2), an industrially important nanomaterial, was investigated in different solution matrices (Milli-Q water, a real landfill leachate, KC1 solution, and humic acid solution). The KC1 and humic acid solutions were used to examine the effects of inorganic ions and humic substances in leachate on the stability of CeO2 nanoparticles. Factors including pH (pH 4 and 8 ) and CeO2 concentrations (0.5 and 0.1 mg/mL) were also evaluated. Results show that the sizes and zeta potentials of the nanoparticles were very stable in the control (Milli-Q water) and humic acid groups but unstable in the leachate and inorganic salt (KC1) solutions. A low pH (pH 4.0) appeared to favor dispersion of the nanoparticles, compared with a high pH (pH 8.0). This study demonstrates that a high pH and inorganic salt concentration facilitated the aggregation of CeO2 nanoparticles.

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