Influence of clay colloids, humic acid and water chemistry on the stability, aggregation and deposition of nanoscale titanium dioxide (nTiO₂)

Tang, Zhong (2017) Influence of clay colloids, humic acid and water chemistry on the stability, aggregation and deposition of nanoscale titanium dioxide (nTiO₂). Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (939kB)

Abstract

Fate and transport of engineered nanoscale titanium dioxide (nTiO₂) have received much attention during the past decade. The stability, concurrent aggregation and deposition of nTiO₂ in water with complicated components, however, have not been fully examined. The objective of this thesis was to determine the individual and synergistic effect of pH, cation valence, humic acid, Fe/Al oxyhydroxide coatings and clay colloids on nTiO₂ stability, aggregation and deposition, and elucidate the related mechanisms. We conducted systematic laboratory experiments to determine nTiO2 stability, aggregation and deposition onto a quartz sand in NaCl and MgCl₂ solutions, both in the absence and presence of humic acid and clay colloids. Results showed that nTiO₂ formed hetero-aggregates and the heteroaggregates may either deposit or remain suspended depending on their interactions with quartz sand and Fe/Al oxyhydroxide coatings. Humic acid was found to make nTiO₂ stable to prevent nTiO₂ aggregation and deposition under most conditions.

Actions (login required)

View Item