XPS study of the ion-exchange capacity of the native and surface oxidized viscose fibers

The viscose fibers were selectively oxidized with N-hydroxyphthalimide (NHPI)/NaClO/NaBr at room temperature to obtain 6-carboxy cellulose with a higher crystallinity than the original material. The capacity of ion-exchange of both original viscose and oxidized fibers has been evaluated with a series of metal salts by using X-ray photoelectron spectroscopy (XPS) technique. The adsorption selectivity of metal ions on the oxidized fibers was investigated using aqueous solutions containing multiple metal salts. The following order of affinity was found: Sn2+ > Al3+ >> Ca2+ > Ag+ > Cu2+ > Pb2+ > Ba2+ > Cs+. Water retention values of the metal carboxylate groups obtained by ion-exchange process are also discussed in terms of sort of metal introduced. (C) 2011 Elsevier B.V. All rights reserved.