Ion-exchange properties of alginate fibers

This paper describes a study of the ion exchange properties of alginate fibers. The release of calcium ions into the contacting solution is measured by an atomic absorption spectrometer. The calcium alginate fibers are placed in aqueous solutions of Na2SO4; with the formation of CaSO4, these fibers can be converted into a mixed calcium/sodium alginate. Results show that the sodium ions in the fibers help increase their gel swelling ratio. Calcium alginate fibers can also be treated with aqueous solutions of ZnCl2, producing mixed calcium/zinc alginate fibers. When put in contact with solutions containing sodium ions, the zinc in the fibers can be released into the solution.