Uptake of multi-disperse starch by anion exchangers


Uptake of multi-disperse starch by anion exchangers

Pürschel, M.; Sachs, S.; Bernhard, G.; Ender, V.

Demineralisation plants of power stations are not able to remove organics in all cases to a satisfied degree. The present work focuses on natural organic matter (NOM) and its interaction with anion exchanger and adsorber resins to optimize organics uptake. In this study, four different starches (one of them 14C-labelled) with different molecular size distributions were selected as model substances for the biopolymer fraction of NOM. Their uptake by various anion exchangers and adsorbers was measured in column experiments. Results are discussed in terms of size exclusion, anion exchange, adsorption, and hydrophilic/hydrophobic repulsion. In summary, at neutral pH, starch has been removed preferably by size-exclusion followed by adsorption, whereas anion exchange resins show higher uptake capacities than “pure” adsorber resins caused by stronger attraction between starch and polar functional groups of the anion exchangers. At acidic pH, the uptake of sulphate, as competitive adsorptive, leads to an earlier starch breakthrough at anion exchangers. Therefore, adsorbers are more effective. It was found, that the higher the water content of the resins, the more effective the uptake is.

Keywords: water treatment; natural organic matter (NOM); anion exchange; adsorption

  • Open Access Logo Journal of Physical Science and Application 3(2013)3, 147-155

Permalink: https://www.hzdr.de/publications/Publ-18469
Publ.-Id: 18469