Electrosurface properties of microcrystalline cellulose of different origin in 1 : 1 electrolyte solutions

Electrosurface characteristics (the exchange capacity and the electrokineti c potential) of the samples of cotton and wood microcrystalline celluloses (MCC) were studied as functions of the pH and the concentration of backgrou nd electrolyte (10(-3)-1M NaCl). It was found that the MCC samples are nega tively charged over the studied pH range (3.5-10.0). The results of measuri ng exchange capacities were used for calculating constants of surface react ions. The values of dissociation constants of the surface groups allow us t o state that the charge of the MCC surface within the studied pH range is m ainly determined by the dissociation of carboxyl groups. The surface and el ectrokinetically mobile charges, concentrations of fixed and mobile ions, a s well as Donnan's potentials were calculated for the studied samples.