Liquid phase adsorption behavior of inulin-type fructan onto activated charcoal.

This study describes liquid phase adsorption characteristics of inulin-type fructan onto activated charcoal. Batch mode experiments were conducted to study the effects of pH, contact time, temperature and initial concentration of inulin. Nearly neutral solution (pH 6-8) was favorable to the adsorption and the equilibrium was attained after 40 min with the maximum adsorption Qmax 0.182 g/g (adsorbate/adsorbent) at 298 K. The experimental data analysis indicated that the adsorption process fitted well with the pseudo-second-order kinetic model (R(2) = 1) and Langmuir isotherms model (R(2) > 0.99). Thermodynamic parameters revealed that the adsorption process was spontaneous and exothermic with a physical nature. Inulin desorption could reach 95.9% using 50% ethanol solution and activated charcoal could be reused without significant losses in adsorption capacity. These results are of practical significance for the application of activated charcoal in the production and purification of inulin-type fructan.