Encyclopedia of Membranes

2016 Edition
| Editors: Enrico Drioli, Lidietta Giorno

Freundlich Isotherm

  • Bart Van der BruggenEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-3-662-44324-8_254

A Freundlich isotherm is a mathematical expression for the adsorption equilibrium between a fluid (liquid or gas) and a solid material. The Freundlich equation is an empirical expression representing the isothermal variation of adsorption of a liquid or gas onto the surface of a solid material, derived by Freundlich (1909) as an empirical relation.

For adsorption of a gas as the adsorbate to a solid adsorbent, the following equation represents a Freundlich isotherm:
$$ \frac{x}{m}=k{P}^{\frac{1}{n}} $$
This is a preview of subscription content, log in to check access.


  1. Freundlich H (1909) Kapillarchemie: eine Darstellung der Chemie der Kolloide und verwandter Gebiete. Akademische Verlagsgesellschaf, LeipzigGoogle Scholar
  2. Ge D, Shi W, Ren L, Zhang F, Zhang G, Zhang X, Zhang Q (2006) Variation analysis of affinity-membrane model based on Freundlich adsorption. J Chromatogr A 1114:40–44CrossRefGoogle Scholar
  3. Kimura K, Amy G, Drewes J, Watanabe Y (2003) Adsorption of hydrophobic compounds onto NF/RO membranes: an artifact leading to overestimation of rejection. J Membr Sci 221:89–101CrossRefGoogle Scholar
  4. McCallum EA, Hyung H, Do TA, Huang CH, Kim JH (2008) Adsorption, desorption, and steady-state removal of 17β-estradiol by nanofiltration membranes. J Membr Sci 319:38–43CrossRefGoogle Scholar
  5. Van der Bruggen B, Braeken L, Vandecasteele C (2002) Flux decline in nanofiltration due to adsorption of organic compounds. Sep Purif Technol 29(1):23–31CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Department of Chemical EngineeringProcess Engineering for Sustainable Systems (ProcESS), KU LeuvenLeuvenBelgium