Abstract
This work was undertaken in order to quantitatively determine the selective absorption of the tanning materials from the solution containing both lignosulfonic acid and the vegetable tannin. For this purpose, a method to determine the vegetable tannin and lignosulfonic acid separately has been first established by colloid-titration. The absorption of the vegetable tannin by hide powder is disturbed by lingosulfonic acid, and this disturbance is remarkable, in case of the tannin having the ionic character. However, if the absorption of tannin by hide powder is non-ionic such as that of Acacia Mollissima, the selective absorption of lignosulfonic acid and tannin does not occur. This is due to the fact that the absorption active center of Acacia Mollissima is different from that of lignosulfonic acid.
