Desorption reaction of ferric ions adsorbed on cellulosic materials by acids

Factors affecting the desorption reaction of ferric ions adsorbed on cellulose and oxidized poly(vinyl alcohol) fibers by acids were investigated. The desorbing effect generally increased with increasing acid concentration, treating temperature, and treating time, although the magnitude of this effect varied somewhat from one acid to another. Oxalic acid, hydrochloric acid, sulfuric acid, sulfurous acid, and phosphoric acid are examples of those acids which show large desorbing effects. Scission of the cellulose chain was also observed under the desorption conditions used for such acids. The desorption reaction may be divided into two stages, an initial fast reaction and a subsequent slow reaction; the activation energies were calculated for each reaction, and values of 7–10 kcal/mole and 5–6 kcal/mole were obtained for cellulose and oxidized poly(vinyl alcohol) fibers, respectively.