Adsorption Behavior of Sodium Hydrogen Sulfate on Silica Gel

The adsorption behavior of sodium bisulfate on silica gel was studied. The adsorption isothem of sodium hydrogen sulfate on silica gel were measured in the temperature range of 298.15 ~ 328.15 K, and the Langmuir model and the Dubini-Radushkevich (D-R) model were used to fit the experimental isotherm data. The average characteristic concentration (Ce') of NaHSO4 was determined at different temperatures to distinguish chemisorption from physisorption. The values of the mean free energy (E) calculated from the D−R isotherm equation indicated that the adsorption of NaHSO4 on silica gel occurs by sequential chemical and physical mechanisms.