Effect of repulsive and attractive interactions in the adsorption of confined polydisperse fluids

A density functional perturbative approximation, which is based on the pair distribution function, has been developed to investigate the influence of attractive and repulsive interactions on the density behaviour of a confined polydisperse fluid. The calculated result shows that the attractive and repulsive interactions in the model potential are strongly affected on the adsorption of a confined polydisperse fluid as well as the cavity size and particle size ratio. The attractive interaction in a polydisperse square-well system increases the pore average mole fraction for small particles in a circular cavity. Whereas a repulsive interaction in a polydisperse square-shoulder system decreases the pore average mole fraction for small particles. The local relative concentration oscillates with a spatial period close to the diameter of a large particle as well as the equilibrium density distribution does.