Diffusion coefficients of biopolymers extracted from Grewia spp. barks in water were studied under various physicochemical conditions. Extractions were carried out on barks of 3 cm in length at different pH (5-9), temperature (25-50°C) and ionic strength (10-3-10-2M), using CaCl2 and NaCl as background electrolytes. Factorial experimental plan design was used and diffusion coefficients were determined using second law of Fick equation, with linear and logarithmic approximation. Obtained results show that diffusion coefficients of Grewia spp. biopolymers are in the range of 9.78458E-06±1.6462E-08 cm2/min, and are not significantly influenced¶not soignificantly influence by the pH, the ionic strength and the temperature. Maximum diffusion was obtained with CaCl2 at high ionic strength. Both linear and logarithmic approximations were found to be suitable for diffusion coefficients and were dependent on the background electrolyte used.
Key words: Biopolymers, diffusion coefficient, Grewia.