Combined concentration polarization and pore-flow modeling to predict the performance of a nanofiltration membrane for NaCI rejection

Abstract

Membrane based filtration techniques are gaining importance day by day for its effectiveness and simplicity [1]. Different pressure driven techniques are exercised for membrane separation; nano filtration is one of them. Nano filtration membranes stand handy for different applications because of their thermal, chemical and mechanical stability [2]. High surface charge of these membranes help in separation of charged species from a solution. This particular property can be used to segregate any type of salt from water. Hence, it can be a useful technique for desalination of water which is a challenge for present day's world [3,4].

Modeling and simulation always provides useful lead to understand the underlying physical phenomenon behind a real life system. It also proves to be useful in scaling up the system and predict its performance in remote scenarios. Transport phenomena based membrane modeling is not a new field of study; a number of works have been reported till date which deals with it. Different studies have been done starting from prediction of different fouling mechanism [5,6] of membranes to prediction of flux for different processes [7,8]. In order to predict the flux and permeate concentration across the membrane a number of theoretical models have been proposed such as (a) osmotic pressure model [9 11]; (b) film theory [12 14]; (c) solution diffusion model; (d) Kedem-Katchalsky equation etc. Each of these models has their advantages and limitations also.