UV Chemistry and Mitigation of Siloxane

摘要

The presence of dimethylsilanediol (DMSD) within the water supply of the International Space Station (ISS) causes issues with the Water Processing Assembly (WPA). It can degrade the WPA catalytic reactor’s effectiveness and cause the early replacement of Multifiltration Beds. The DMSD is believed to be a decomposition product of siloxanes which are condensed into the water system with the humidity condensate. This paper presents the ultraviolet (UV) gas phase photochemistry of siloxanes under both long and short wavelength UV radiation, and high energy electron bombardment. The results of this study showed that the siloxanes reacted into progressively larger and more complex moieties which eventually formed large non-volatile components which included their attachment to various accessible surfaces.