Author

Mahdavi

Date of Award

4-1999

Degree Name

Master of Science

Department

Chemical and Paper Engineering

Department

Paper Engineering, Chemical Engineering and Imaging

First Advisor

Dr. Raja Aravamuthan

Second Advisor

Dr. David K. Peterson

Access Setting

Masters Thesis-Open Access

Abstract

The use of chlorine containing bleaching process creates various organic compounds such as chlorinated furan, dioxin, and AOX (adsorbable organic halogen). The human and aquatic life has been affected with the formation of these chlorinated organic compounds. EPA is proposing new regulations to impose discharge limits on the conventional pollutant materials of the bleaching effluents.

The objective of this research was to evaluate two TCF (Total Chlorine Free) bleaching sequences that use hydrogen peroxide and DMD on oxygen delignified hardwood kraft pulp. In one of the sequences, the DMD stage (A) was used prior to the hydrogen peroxide stage (P), and in the other, the DMD stage was used after the hydrogen peroxide. Oxygen delignified hardwood kraft pulp was chelated (Q) prior to bleaching with peroxide and DMD.

Both OQAP and OQPA bleached pulps resulted in brightness above the 80's with comparative paper properties. The OQAP bleaching sequence significantly gave a higher brightness, viscosity, burst strength, and pentosan content than OQPA. Statistical analysis shows no difference in tear and tensile in different bleaching sequences. Both OQAP and OQPA bleaching sequences were the same in alpha cellulose content. OQAP has less beta cellulose and higher gamma cellulose content than the content of OQPA bleached pulp.

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