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Published on: November 25, 2020
Interaction forces between waterborne bacteria and activated carbon particles
Henk J Busscher1, Rene J B Dijkstra, Don E Langworthy
1Department of Biomedical Engineering, University Medical Center Groningen, and University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
Journal of Colloid and Interface Science
|April 15, 2008
Summary
Activated carbons remove bacteria from water via attractive forces, overcoming repulsion. Positively charged carbons and coconut carbons showed higher bacterial adhesion, improving water purification.
Area of Science:
- Environmental Science
- Microbiology
- Materials Science
Background:
- Activated carbons are used to remove waterborne bacteria from drinking water.
- Removal mechanisms involve attractive Lifshitz-van der Waals forces, despite electrostatic repulsion between negatively charged bacteria and carbon surfaces.
Purpose of the Study:
- To quantify interaction forces between bacteria and differently charged activated carbons.
- To investigate the influence of carbon surface charge and porosity on bacterial adhesion.
Main Methods:
- Atomic Force Microscopy (AFM) was used to measure interaction forces.
- Carbon particles were attached to AFM cantilevers to probe bacterial surfaces.
- Experiments involved waterborne bacteria (Raoultella terrigena, Escherichia coli) and various activated carbons (mesoporous wood-based, microporous coconut).
Main Results:
- Weak adhesion forces (1-2 nN) were observed between bacteria and activated carbons.
- The percentage of attractive interaction sites varied significantly (21-69%) across different carbon types and bacterial strains.
- Higher adhesion percentages were noted for positively charged carbons and coconut carbon, particularly with R. terrigena.
Conclusions:
- Bacterial removal efficiency by mesoporous carbons correlates with the percentage of attractive interaction sites.
- Surface charge and pore structure of activated carbons are critical factors in bacterial adhesion and removal from water.
- Understanding these forces can optimize activated carbon-based water treatment technologies.
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