Polypyrole/molecular sieve 13X composites to CH4, CO2, CO, and SO2 : effects of cation type and cation concentration

Abstract

Electrical conductivity sensitivity of polypyrrole(Ppy)/molecular sieve 13X composites exposed to CH4, CO2, CO, and SO2 was investigated. Composites were prepared by dry mixing. Effects of molecular sieve 13X concentration, cation type, concentration of cation were investigated. The electrical conductivity of Ppy doped with naphthalene-2-sulfonic acid(B)sodium salt depends on the doping level. There is no electrical conductivity response when Ppy and its composites are exposed to CH4, CO2, and CO in contrast to thepPpy exposed to SO2. Undoped Ppy and doped Ppy composites at 10% v/v of 13X content possess the highest sensitivity to SO2; the sensitivity is reduced as molecular sieve 13X content increases. Cation-exchanged processes on the molecular sieve 13Xwere carried out by changing from Na+ to Li.+ K+, and Cs+ at various amounts The composites of unmodified 13X in which Na+ is fully present give the greatest sensitivity to SO2. The sensitivity of Ppy/13X composite to SO2 is reduced by exchanging cation in molecular sieve 13X from Na+ to other alkali cations in this decreasing order: cs+,K+, and Li+.