Continuous filtration and titration apparatus for real time monitoring of polyelectrolyte concentration and cationic demand of a paper furnish

This paper presents the application of a continuous real-time colorimetric titrator coupled to a continuous filtration apparatus, allowing polyelectrolyte concentration and cationic demand measurements to be undertaken on a paper furnish. A continuous filtration device is utilized that selectively separates dissolved and colloidal substances (DCS) from a paper furnish. By utilizing a back titration procedure, it was possible to utilize the continuous titration apparatus directly on the filtrate in order to monitor furnish charge on a pulp sample in real-time. The apparatus was utilized to study the dynamics of polyelectrolyte adsorption onto fiber surfaces, as well the change of fiber surface charge at varying pH values and for different pulp samples taken from the bleaching process of a kraft pulp.