Date of Award
Bachelor of Science
Pulp and Paper Technology
Dr. R. A. Diehm
In recent years the problem of pollution has gained more importance in the pulp and paper industries due to the pressures applied by the State and Federal Governments. One of the areas in which the industry has been weak is the coagulation of starch-titanium white water. The problem is largely due to the stabilizing power of the modified starches used in the industry today. These starches peptize the pigment which is present in the white water and form a highly stable colloidal system.
The coagulating rules set down in the Schulze-Hardy Law and the Hofmeister Series state that the higher the valence on either a cation or an anion in solution, the greater the coagulating power. This is due to the neutralizing of the zeta potential associated with each colloidal particle. However, it has been shown in the following work that for the highly sheared system of Pearl starch and titanium dioxide that a combination of Mg+2 and SO4-2 ions have a greater coagulating power than Al+3 and SO4-2. This has been attributed to an explained reaction between the Mg+2 ions and the pepitized titanium particle which favors the formation of larger flocculated particles.
O'Hara, Thomas R., "The Schulze-Hardy Law and the Hofmeister Series of Ions in Coagulations of Starch-Titanium Dioxide White Water" (1969). Paper Engineering Senior Theses. 416.