Facilitated transport of ethylene across polymer membranes containing silver salt: Effect of HBF₄ on the photoreduction of silver ions

Silver salts dissolved in amide group containing polymer such as poly(2-ethyl-2-oxazoline) (POZ) are labile to reduce to silver metals under UV-Vis light or heat. Since the reduction of silver ions to silver nanoparticles can change the separation performance of facilitated olefin transport through polymer membranes containing silver salt, it is attempted to prohibit the reduction of silver ion. It is found that the trace of water present in silver-polymer complex membranes participates in the reduction reaction and H⁺ ions are generated in a reversible reaction of the reduction process. In this respect, tetrafluoroboric acid (HBF₄) was introduced as a proton donator to suppress the reduction of silver ion. The effects of HBF₄ on the photoreduction derived by UV irradiation were characterized by mixed gas transport of ethylene/ethane, UV-Vis spectroscopy, scanning electron microscopy (SEM).