Sorption/desorption of sulfur dioxide by cellulosic fibers

Author

Geraldine Mahany Eaton

Date of Award

12-1986

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Human Ecology

Major Professor

Bhuvenesh C. Goswami

Committee Members

T. L. Vigo, K. E. Duckett, L. C. Wadsworth, M. H. Lietzke, D. B. Eastwood

Abstract

The purpose of this study was to determine the mechanism and degree of SO² sorption by native cellulose (ethanol extracted cotton), modified cellulose (mercerized cotton and liquid ammonia treated cotton), and regenerated cellulose (viscose rayon) under dynamic environmental conditions. The effects of fiber fine structure, moisture content, and temperature on SO² sorption were examined as well.

An exposure chamber was developed which would simulate ambient conditions. Fiber samples were dried or conditioned to 69 ± 1% RH and exposed to 3 ppm SO^ for 5 hours at 170 cc/min. Following exposure to SO² the samples were exposed to a stream of dry air at the same flow rate for 4 hours. The concentration of gas exiting the chamber was monitored and compared with the known concentration of gas introduced into the chamber to evaluate the amount of gas sorbed.

For the dried fiber exposures, mercerized cotton sorbed more SO² ^ at each temperature than any other fiber. Dried viscose rayon sorbed the least SO^ at each temperature. Conditioned fiber samples sorbed more SO² than dried fiber samples. The rates of SO² desorption were similar for all samples.

Several instrumental techniques were used to evaluate the presence of sulfur remaining in the fibers following desorption. X-ray spectroscopy showed small sulfur peaks on exposed extracted cotton, mercerized cotton, and NH₃(l) treated cotton. ESCA and FTIR were unable to confirm the presence of residual sulfur in the samples. Total sulfur analysis showed only similar trace amounts of sulfur in unexposed and exposed cotton. Fiber fine structure, moisture content, and temperature were all found to affect the rate and magnitude of SO² sorption. Sulfur dioxide sorption increased with decreasing molecular order, increased with the addition of fiber moisture, and decreased with increasing temperature.

The mechanism of SO² sorption by cellulose is thought to be physical sorption with van der Waals forces forming the basis for attraction. Sorption by both dried and conditioned fibers is reversible. All of the SO² was desorbed following exposure of the samples to a stream of dry air.

Recommended Citation

Eaton, Geraldine Mahany, "Sorption/desorption of sulfur dioxide by cellulosic fibers. " PhD diss., University of Tennessee, 1986.
https://trace.tennessee.edu/utk_graddiss/12241