Transport of Low Molecular Weight Anions through a Nafion Ionomer Membrane: Application to Kraft Cooking Liquors

The permeation of low molecular weight anions from liquors having high ionic strengths through a Nafion 811 membrane in Na+ form has been studied. The penetration of solutes through the membrane was monitored using UV-visible spectrometry. A relation between penetration and ionic size has been established. The influence of the presence of other ions on the permeation has also been investigated. The results show that the membrane has great potential as part of a selective interface in applications where the concentration of small anions is to be monitored in media with high ionic strengths. In light of the new results, we have validated a previously developed system for monitoring the concentrations of hydrogen sulfide ion and dissolved lignin in a laboratory-scale kraft cooking system.