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Nonionic surfactant sorption onto the bacterial cell surface: a multi-interaction isotherm
Derick G Brown1, Khaula S Al Nuaimi
1Department of Civil & Environmental Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, USA. dgb3@lehigh.edu
Langmuir : the ACS Journal of Surfaces and Colloids
|November 16, 2005
Summary
Polyoxyethylene (POE) alcohol surfactant adsorption on Sphingomonas sp. bacteria was studied. Increasing POE chain length reduced lateral interactions and altered adsorption isotherms, impacting surface aggregation.
Area of Science:
- Environmental microbiology
- Surface chemistry
- Biophysics
Background:
- Surfactant adsorption influences microbial surface properties and environmental fate.
- Polyoxyethylene (POE) alcohol surfactants are widely used but their interaction with bacterial surfaces requires further elucidation.
Purpose of the Study:
- To investigate the adsorption behavior of linear polyoxyethylene (POE) alcohol surfactants (CxEy) on Sphingomonas sp.
- To determine the effect of varying POE chain lengths on surfactant adsorption isotherms and surface interactions.
Main Methods:
- Adsorption experiments using Sphingomonas sp. and a series of C12E_y surfactants (y=4, 7, 9, 10, 23).
- Analysis of adsorption isotherms to model surface interactions.
- Proposed a multi-interaction model to describe sorption phenomena.
Main Results:
- Langmuirian isotherms were observed for C12E4 and C12E23.
- Complex, S-shaped isotherms were observed for intermediate POE chain lengths (C12E7, C12E9).
- Adsorption plateau decreased with increasing POE chain length, indicating reduced lateral interactions.
Conclusions:
- A multi-interaction model successfully describes the observed adsorption isotherm variations.
- Lateral interactions between adsorbed surfactant molecules are dominant for shorter POE chains and decrease with increasing POE length.
- POE chain length is a critical factor modulating surfactant adsorption and surface aggregation on bacterial surfaces.