PHASE-DIAGRAMS OF A FLUID CONFINED IN A DISORDERED POROUS MATERIAL

We present the calculation of phase diagrams for a single-component fl uid adsorbed in disordered porous material using integral equation the ories. The model consists of a Lennard-Jones 12-6 fluid confined in a rigid matrix of spheres. In most cases a vapour-liquid coexistence cur ve is obtained. It is similar to that observed for the bulk fluid alth ough displaced towards the phase that adsorbs preferentially. The ORPA + B-2 approximation also predicts the appearance of a second fluid-fl uid phase transition at low temperature that may be consistent with th e narrowing of the coexistence curve observed in experiments.