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Diffusioosmosis, also referred to as capillary osmosis, is the flow of a solution relative to a fixed object, where the flow is driven by solute concentration gradient. The solution considered here is an aqueous mixture containing colloids that flows in a channel and through an array of cylinders, representing a membrane. In this work we use an adaptation of the suspension balance model to investigate the influence of colloid – interface (?ic) interaction and colloid – colloid interactions (?cc) on the diffusioosmosis of a colloidal suspension. The model describes both osmosis and Marangoni flow, depending on the attractive or repulsive nature of ?ic. Further, ?cc dictates two important features of the flow. First, increasing the gradient of colloid concentration between the two channels by a factor of 10 increases the pressure drop by a factor of ~3.2 in the advection – osmosis equilibrium state. Second, including higher-order terms from the hard-sphere repulsion model (via the Carnahan-Starling equation of state) can increase colloid concentrations near the membrane by ~30%.

This paper presents a framework for finding homogeneous entrainers E to separate non-ideal mixtures AB by extractive distillation. The framework is a systematic approach to convert a Computer Aided Molecular Design into a mixed integer non-linear program (MINLP). It is based on the thermodynamic properties of binary mixtures AE and BE and of isovolatility curve maps of the ternary mixture ABE. Entrainer candidates are ranked by the maximization of the driving force of A and B in their respective mixtures AE and BE as well as by minimizing the entrainer composition xE corresponding to a fixed value of the relative volatility aAB. The framework application is highlighted through an entrainer problem design for the separation of acetone – methanol by extractive distillation process.

The topological structure of univolatility curves of ternary homogeneous mixtures is derived from the boiling temperature and univolatility hypersurfaces geometry. The key point is the concept of the generalized univolatility curve in the 3D state space, which allows putting in evidence the bifurcation mechanism of the sets of the univolatility curves and to tune-up an efficient numerical algorithm for their computation by a simple integration of a system of ordinary differential equations. Two examples of different two types of bifurcation are presented by varying pressure in order to modify the topology of the ternary residue curve map.