Standard Article


Membrane Processes

  1. Zoltán Kovács1,2,
  2. Peter Czermak3,4

Published Online: 27 SEP 2013

DOI: 10.1002/9781118522318.emst078

Encyclopedia of Membrane Science and Technology

Encyclopedia of Membrane Science and Technology

How to Cite

Kovács, Z. and Czermak, P. 2013. Diafiltration. Encyclopedia of Membrane Science and Technology. 1–46.

Author Information

  1. 1

    University of Applied Sciences Mittelhessen, Giessen, Germany

  2. 2

    Corvinus University of Budapest, Budapest, Hungary

  3. 3

    Justus Liebig University, Giessen, Germany

  4. 4

    Kansas State University, Manhattan, USA

Publication History

  1. Published Online: 27 SEP 2013


Membrane filtration represents a unique separation technique as it can be employed for both concentrating and purifying a multicomponent process stream. To achieve these twin-objectives, diafiltration is required. Diafiltration is an operation mode of a pressure-driven membrane filtration process in which a diluant (i.e.,∼water or any other solvent or buffer) is added to the process liquor in order to enhance the degree of separation of membrane-retained macrosolutes from membrane-permeable microsolutes. Depending on the separation target, diafiltration may be performed with microfiltration, ultrafiltration, nanofiltration, or reverse osmosis membranes. The separation target can be reached by using either batch or continuous processing mode. Diafiltration is an indispensable tool in separating multicomponent process streams and widely used in the food and beverage, chemical, biotechnological, and pharmaceutical industries. This article introduces the reader to the fundamentals of diafiltration. It provides a brief survey on the most important applications and discusses the various configurations, general design equations, control strategies, and diluant utilization strategies used in batch and continuous diafiltration practice


  • diafiltration;
  • microfiltration;
  • ultrafiltration;
  • nanofiltration;
  • reverse osmosis;
  • batch membrane filtration;
  • continuous processing