Abiotic and biotic mitigation of volatile methyl siloxanes in anaerobic gas-phase biomatrices

Gabriela Soreanu1,2, Patricia Falletta1, Michel B land1, Kara Edmonson1, Peter Seto1

1 Environment Canada, Aquatic Ecosystems Management Research Division, Burlington, Ontario, Canada
2 Gh. Asachi Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, Iasi, Romania

Abstract


This paper presents preliminary results of a batch-scale study assessing the contribution of the multiple phenomena involved in siloxane removal in three-phase biomatrices. Batch scale experiments were undertaken in shaken flasks containing acclimatised culture medium, solid media and siloxane vapours (octamethylcylotetrasiloxane and decamethylcyclopentasiloxane, respectively) under anaerobic gas-phase conditions. Abiotic and biotic phenomena, considered to be possible siloxane removal mechanisms, were monitored via the silicon-mass balance. The maximum siloxane removal efficiency in the gas-phase reached 44-82%, depending on the type of solid media and the siloxane compound tested. The dominant removal mechanism was abiotic in all cases. The formation of colloidal siloxane dispersions was observed, simultaneous with siloxane adsorption on solid media and some biological degradation. These experimental observations may be beneficial for the development of new methods for siloxane removal from gas fluxes, particularly biogas.

Keywords


abiotic; biodegradation; biotic; decamethylcyclopentasiloxane; octamethylcylotetrasiloxane

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