Facilitated Transport of Formaldehyde across Hydrogensulfite Ion Form Anion-Exchange Membrane

Formaldehyde was transported efficiently across hydrogensulfite ion form anion-exchange membrane via the adduct formation reaction. The transport of formaldehyde was facilitated but onlywhen the concentration of formaldehyde in the source phase solution was low. The ion-exchange capacity of the membrane was saturated by formaldehyde distributed as its adduct in a low source phase concentration because the adduct formation constant was high. The transport of formaldehyde can be further facilitated and formaldehyde was transported against the concentration gradient with the counter-transport of hydrogensulfite ion when hydrogensulfite salt was added to the receiving phase.