RESUMEN

In this research, the recovery of dissolved biogas (CO2/CH4) from synthetic anaerobic effluents was studied using non-porous, polydimethylsiloxane (PDMS), hollow-fibre gas-liquid membrane contactors towards the design of a reduced carbon-footprint integrated bioprocess. As a key parameter, the gas-to-liquid (G/L) ratio (employing argon as sweep gas) was systematically varied in the range of 0.5-2.0. The results showed on a 1 m2 PDMS module that increasing the liquid (effluent) flow rate favours the CH4 transport, while a higher sweep gas flow rate is preferable for the CO2 transport over CH4. Depending on the actual biogas composition and the CO2 content of the effluent, the methane recovery could be improved up to 63 % under steady-state conditions. In general, similar tendencies were observed when another PDMS membrane module with a smaller surface area (2 500 cm2) was applied hence, in this sense, the separation behaviour seems to be independent of the membrane size.