(173e) Generation of Negative Ion Species in the Gas Phase from a 12CaO•7Al2O3 Membrane-Coated Ceramic Heater Under Atmospheric Pressure

The nanoporous crystal 12CaO•7Al₂O₃(C12A7) is able to discharge strong and high purity oxygen anions (O^-) under reduced pressure. The O^- ion is expected to be one of the most active radical for potential applications such as the oxidation of thin film, sterilization, and the removal of environmental pollutants. However, the characteristics of the O^- ion emission from C12A7 under atmospheric pressure have not been evaluated, although the characteristics under reduced pressure were investigated in previous studies. In this study, the characteristics of negative ion species emissions from a C12A7 membrane coated on seramic heater under atmospheric pressure were investigated by quadrupole mass spectrometry. Negative ion species were confirmed to be emitted from the C12A7 membrane under atmospheric pressure. It was supposed that the detected negative ion clusters, such as O^-(H₂O)_n, O₂^-(H₂O)_n, and CO₄^-(H₂O)₄, were generated by the reaction of negative ions included electrons emitted from the C12A7 membrane with impurities in He gas.