GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Tuesday, April 30, 2019

4:30 PM
in MoSE 4100F

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Jiwoo Yu

"Cellulose-based Magnetic Core/Shell Microspheres for Water Purification"

Committee Members:

Prof. Zhiqun Lin, Advisor, MSE

Prof. Yulin Deng, ChBE

Prof. Seung Soon Jang, MSE

Prof. Meisha Shofner, MSE

Prof. Vladimir Tsukruk, MSE

Abstract:

Traditional water supply is currently facing grand challenges due to recent new regulations on lowering pollutant levels as a result of deteriorated water quality in the world. In this context, nanomaterials offer the opportunity to innovate water purification technology with decreased cost and size as well as improved selectivity over a wide range of pollutants. Nano-adsorbents can be further improved in effectiveness or process design when integrating with scaffolds by preventing agglomeration and maintaining more accessible active sites for pollutant adsorption. Despite recent progress in employing nanoparticles-impregnated scaffolds for water treatment, effective methods to yield low-cost, large-scale and environmentally friendly nanocomposites are comparatively few and limited in scope.

To this end, we developed low-cost, non-toxic paraffin/cellulose core/shell microsphere scaffold that can integrate with hydrophilic and hydrophobic nano-adsorbents for water treatment. The ability to impregnate nano-adsorbents of different surface chemistry renders the flexibility for targeted purification. In this study, hydrophobic Fe3O4 nanoparticles and hydrophilic Fe3O4 thin-sheets are successfully integrated with hydrophobic paraffin core and hydrophilic cellulose shell, respectively. The hydrophilic cellulose shell also enables colloidal stability in water that increases the adsorption effectiveness for pollutants, while the hydrophobic core imparts mechanical strength. Such cellulose-based magnetic core/shell microspheres will be evaluated for methylene blue, Cu(II), and Pb(II) adsorption in waste water. Due to the incorporation of magnetic nanoparticles within core/shell microspheres, they can be readily collected and recycled from water with magnet for complete and repeated removal of the adsorbents.