Sorp‐Vection‐Based Membrane Silicone Oil Purification

Abstract

Abstract “Sorp‐vection” is a membrane separation technique that synergistically combines sorption with convective flow mechanisms. Beyond its conceptual discussion, we demonstrate a sorp‐vection separation achieved in a gas–liquid system, where permeation of a gas directly drives selective permeation of an organic solute across a dense polymer layer overcoming osmotic limitations of conventional membrane processes. Here, a long‐standing challenge in silicone oil production is addressed, in which residual cyclic oligosiloxanes are removed from silicone oil streams through permeation of CO 2 across an optimally crosslinked PDMS selective layer. A lab‐scale 1 st generation Sorp‐vection system demonstrated, with a separation factor above 15 to remove D4 (octamethylcyclotetrasiloxane) from low‐concentration feeds using both lab‐grade silicone oil (Sigma‐Aldrich) and an industrial‐grade feed (DOW‐SFD). Good agreement was found with a predictive model based on liquid D4 and high‐molecular‐weight silicone oil sorption data in crosslinked PDMS. This proof‐of‐concept study introduces the sorp‐vection strategy, expanding it from conventional two‐component systems to a three‐component configuration in which convective flow is introduced as an independent driving entity. Addressing concentration polarization in next‐generation versions of the sorp‐vection process is expected to ensure stable long‐term performance and to establish sorp‐vection as a transformative approach for industrial purification.