Adsorption from oversaturated aqueous solution: Mean force molecular simulations

The squeeze out of benzene from an aqueous solution to a planar graphite wall is considered by molecular simulations. The system contains 1–10 benzene molecules in water at T = 300 K and p = 1 bar corresponding to an oversaturation from 10 to 100. Local density profiles are obtained from the mean force method with a particle balance. For improving the accuracy, standard simulations results are incorporated into the mean force method. The resulting density profiles of benzene show a first peak at the wall with parallel and a second with perpendicular orientation of the molecules. For larger distances from the wall the structure levels out and for up to 40‐fold oversaturation a limiting density of 25.8 ± 3.6 mmol/l is obtained. This value is in surprisingly good agreement with the experimental solubility limit of 22.8 mmol/l. The method may also be used for obtaining liquid–liquid equilibria. © 2008 American Institute of Chemical Engineers AIChE J, 2008