A novel methodology in design and simulation of membrane-based purification of organic solvents is proposed. A solution of water and alcohol served as model feed. Mass transfer and momentum transfer equations were derived and solved numerically to obtain the process output as function of process parameters. Water was taken as penetrant throughout the simulations. The studied process was pervaporation in which a nonporous polymeric membrane is used for purification of ethanol. Feed inlet concentration and velocity were considered as process input, water outlet concentration and removal efficiency as output. The Maxwell-Stefan mass transfer approach was applied for estimation of diffusion, the finite element approach for numerical simulation of the process. A lower feed velocity increased the water removal efficiency.