A method of making an insert and an insert for aldehyde absorption having a co-continuous interconnecting channel morphology comprising at least three components, (a) wherein component A is selected from the group of polymers that are semicrystalline polymers and amorphous polymers, wherein the amorphous polymers have a shear modulus greater than about 8 MPa; (b) wherein component B is a polymer; (c) wherein components A and B are immiscible within each other and, if components A and B react after mixing, components A and B are immiscible prior to reaction; (d) wherein component C is a particle and comprises a sulfite compound; (e) wherein the volume fraction of component A represents at least about 50% by volume of the total volume of components A, B and C; (f) wherein the preferential affinity between component B and component C is greater than between component A and component C; (g) wherein at least two phases are formed, one phase is composed of a majority of component A, and the second phase is composed of a majority of component B and a majority of component C; and (h) wherein the two phases form the co-continuous interconnecting channel morphology.