Author

Raval

Date of Award

6-1996

Degree Name

Master of Science

Department

Chemical and Paper Engineering

Department

Paper Engineering, Chemical Engineering and Imaging

First Advisor

Dr. Raymond L. Janes

Second Advisor

Dr. Raja Aravamuthan

Third Advisor

Dr. Brian Scheller

Access Setting

Masters Thesis-Open Access

Abstract

Conventional deinking is the process of removing the ink from usable paper fiber. Electrographic toners are hydrophobic in nature because they have negligible negative charge. A study of the effect of fundamental properties leading to electrographic toner flotation in presence of free fibers has not been reported.

Flotation deinking of fused "sharp" toner fraction below 300 micron in the presence of free fibers was performed in the Hallimond tube. Cationic (Dodecyltrimethyl ammonium bromide - DTAB) and anionic (Sodium dodecyl sulfate - SDS) surfactants having similar molecular weights were used at two concentration levels and two pH levels. The effect of surfactant concentration, surfactant type, and pH on flotation efficiency was studied.

Both surfactants showed higher flotation efficiency in an alkaline environment and with increasing concentration. Cationic surfacatnt (DTAB) led to better flotation compared to the anionic surfactant. There was no generic correlation between contact angle, zeta potential, and flotation efficiency. However, for a particular surfactant (DTAB) at a given pH (9.0), both zeta potential and contact angle are in correlation with percent of surfactant used.

Cationic surfactant gave the highest flotation efficiency at higher concentration and at alkaline pH.

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