Recent advances in technologies for the removal of volatile methylsiloxanes: A case in biogas purification process

Volatile methylsiloxanes (VMS) exist as trace impurities in biogas and hamper the effective utilization of biogas. Various technologies, including adsorption, absorption, membrane separation and biological degradation, are used for the removal of VMS in biogas purification process. This work aims to summarize the recent advances of these technologies. Their advantages/disadvantages and factors that affect the removal efficiency of VMS are analyzed and discussed. Particular attention is paid to adsorption for its highest purification efficiency among the current VMS control technologies. Decrease of the adsorbed capacity under high humidity atmosphere and incomplete desorption are unavoidable conundrums at the present stage. The origination and influenced pathways of these issues are elaborated. Finally, research directions of these technologies for a further development are suggested to fulfill a high VMS removal efficiency and deep understanding of mechanisms.