Foam separation as a method of water and effluent purification

Irwin, R.A., 1978. Foam separation as a method of water and effluent purification. PhD, Nottingham Trent University.

10290237.pdf - Published version

Download (84MB) | Preview


The factors governing virus inactivation and removal during water treatment by foam flotation were assessed using a bacteriophage (MS-2) and a quaternary ammonium surfactant (Arquad T50) as a model system. The importance of virus aggregates was recognized and comparison of various deaggregation procedures showed that dilution in distilled water effectively caused complete dispersion with no loss of infective titre. The phage was resistant to pH inactivation within the range 5.0 to 8.0 with maximum survival at pH 6.0. Using a specially developed isoelectric focussing technique, MS-2 was found to exist in one of two interchangeable states characterized by isoelectric points at pHs of 4.1 and 7.6. This was postulated to result from reversible, configurational alterations in the coat proteins.

The toxicity of cationic and anionic detergents was found to increase abruptly at the higher and lower isoelectric points respectively. This pH-dependent inactivation resulted from ionic interaction of the polar groups with the coat proteins. The inactivation rate decreased with time and this was postulated to result from interference by the adsorbed hydrocarbon groups of the surfactant molecules. This hydrophobic adsorption also caused some inactivation and activation energies for the ionic and non-ionic inactivation mechanisms were calculated to be 33.7 kJmole-1 and 43.2 kJmole-1 respectively.

Ions enhanced surface inactivation in aerated suspensions to an extent related to their size and charge. In laboratory flotation experiments however, they reduced both inactivation and removal by Arquad; this ionic interference again being proportional to ionic radius and charge.

These results were interpreted in terms of the effects of surfactants and ions on the hydrated layers surrounding bubbles and virus particles. Many similarities with the regulating action of reagents in mineral flotation were noted and it was concluded that in this context, the behaviour of viruses was analogous to that of mineral particles.

Item Type: Thesis
Creators: Irwin, R.A.
Date: 1978
ISBN: 9781369324860
Divisions: Schools > School of Science and Technology
Record created by: Linda Sullivan
Date Added: 24 Jun 2021 10:53
Last Modified: 19 Oct 2023 10:17

Actions (login required)

Edit View Edit View


Views per month over past year


Downloads per month over past year