Date of Award

Summer 8-18-2023

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)


Chemical Engineering


Peter Van Walsum

Second Committee Member

Sampath Gunukula

Third Committee Member

M. Clayton Wheeler


In this investigation we propose a novel method to enable precipitation of desired solutes using photo-isomers in the extraction solvent. This photo-switchable solvent would enable dissolution or precipitation of desired components using alternating UV or visible light to modify the solubility of the compounds of interest. Three photo-isomers namely native azobenzene, diethoxy azobenzene and diethylamino azobenzene were studied in three different organic solvents: medium chain length alcohol, ethanol and acetone. It was found that among the different combinations of solvent and photo-isomer, acetone and the 4,4’-diethoxy azobenzene solution was most efficient at precipitating dissolved lignin in response to UV light exposure. This system was able to precipitate 20% of the initial amount of lignin added.