The Effectiveness of Hollow Fibre Membranes in Transferring Flue Gas into Microalgal Culture for Sequestration Purposes

Abstract

Efficient gas transfer remains a technical limitation for microalgal sequestration of greenhouse gases. Hollow fibre membranes (HFM) have been shown by previous researchers to provide high mass transfer efficiency of CO2 gas into solution. The effectiveness of these membranes in transferring CO2 and NOx to microalgal cultures in terms of gas sequestration versus standard sparging has not been completely studied however which is the aim of this research. Microalgal cultures were grown separately using a HFM and a standard bubble diffuser with both 100% CO2 and 24% CO2/350 ppm NOx flue gas mixtures to test the effects that the gas transfer method might have on algal production and sequestration capabilities. Gas flow to the cultures was recorded and algal biomass was analyzed for carbon and nitrogen content to determine sequestration efficiency. HFM cultures showed slightly improved CO2 gas sequestration at the end of growth. Nitrogen fraction in algal biomass was nearly double in the HFM culture to the diffuser when cultivated with NOx gas meaning higher NOx sequestration.