Date of Award


Degree Name

Bachelor of Science


Paper Science and Engineering


Concern for the environment has grown dramatically over the last two decades. In response to this concern, flotation deinking has become a popular way to recycle paper, reduce waste, and achieve a relatively white pulp without cutting down more trees and operating a bleach plant. However, the inks are becoming more and more difficult to deink. With the rise of photocopiers and laser printers the amount of electrographic toner in recycled paper has increased dramatically. Therefore, research on how best to remove these inks from paper is required.

The effects of pH, surfactant concentration, surfactant charge, and toner charge on the efficiency of deinking of paper printed with electrographic inks were evaluated in this study. Deinking was done in the Hallimond tube on a positively charged toner (Canon) and a negatively charged toner (Xerox) using dodecyltrimethyl ammonium bromide (DTAB) for a cationic surfactant and sodium dodecyl sulfate (SDS) for an anionic surfactant.

A higher surfactant concentration (up to about 2%) gave greater deinking efficiency. The anionic surfactant (SDS) at alkaline pH gave better flotation of both toners than the cationic surfactant (DTAB). For both surfactants, alkaline pH led to better deinking.