Abstract: Baicalin is a kind of flavonoids and extracted from the roots of Traditional Chinese Medicine Scutellaria baicalensis Georgi.It has antibacterial,diuresis,anti-inflammatory,spasmolysis and antitumor function.However,baicalin has hygroscopicity due to the polar groups of the hydroxyl and the carboxyl,so the objectives of this study were to investigate the effects of temperature and relative humidity on the hygroscopicity characteristics of baicalin,and to develop an adsorption isotherm model.Results showed that low temperature and high relative humidity led to higher equilibrium moisture content for moisture adsorption processes.At higher temperature,the equilibrium moisture content was reached over a shorter time indicating a higher adsorption rate;relative humidity was also positively correlated with the adsorption rate.To fit experimental data results indicated that the double exponential model was the most suitable for fitting the moisture adsorption kinetics curve and the Peleg model was the most suitable for fitting the adsorption isotherm with R² = 0.9984 for baicalin by the 1stOpt statistical analysis software package.

Key words: adsorption isotherm, adsorption kinetics curve, baicalin, model fitting