Desalination, 2nd Edition

Chapter 4Nanofiltration – Theory and Application

Christopher Bellona

Clarkson University, USA

Abstract

Nanofiltration (NF) represents a relatively recent development in membrane technology with characteristics that fall between ultrafiltration (UF) and reverse osmosis (RO). NF membranes capable of ion and small uncharged solute separation (i.e., loose NF) represent a unique membrane process that can be used for a variety of applications. With effective pore sizes in the range of 1 nm, solute removal is believed to be a function of steric hindrance, and Donnan and dielectric exclusion which, allows for manipulation of the NF process to achieve preferential removal of multi-valent ions, separation of uncharged solutes based on size, and demineralization of process streams containing valuable constituents. Significant recent interest in the use of NF for a wide variety of separation processes indicates that further membrane development will lead to increased use of NF in the near future. This chapter provides an overview of NF technology including history, theory and application.

Keywords: Nanofiltration, ultrafiltration, reverse osmosis, membrane, desalination, water treatment, water reuse, industrial applications, rejection, separation

4.1 Introduction

Nanofiltration (NF) represents a relatively recent development in membrane technology with characteristics that fall between ultrafiltration (UF) and reverse osmosis (RO). NF has been engineered to provide selective separation ...