Uptake of NOM fractions by anion-exchange resins in demineralization plants

Abstract

The elimination of natural organic matter (NOM) is an important objective of water treatment in demineralization plants of power stations, because NOM is considered to be a corrosion risk factor in the steam water cycle. The aim of this study was to compare the performance of different anion-exchange resins (AERs) relating to their NOM fractions removal in demineralization treatment (input water with acidic pH after cation exchange). NOM removal was assessed using the dissolved organic carbon (DOC) measurement and the liquid chromatography–organic carbon detection (LC–OCD) method. At acidic pH, weak base AERs with their higher total volume capacities (TVCs) showed also higher NOM uptakes in comparison with strong base AERs. Further, the macroporous polystyrene weak base AER MP64 was found to be the most effective AER for the removal of problematic NOM leakage fractions (hydrophobic organic carbon (HOC), biopolymers, low-molecular-weight (LMW) neutrals) before the breakthrough point of the stronger adsorbed anions.

Keywords:

• Natural organic matter (NOM)
• Demineralization
• Anion-exchange resin (AER)
• Adsorption
• Water treatment

Acknowledgments

The authors thank Dr Torsten Lehmann for helpful support in water sampling and analysis in the power plant Boxberg and stud. chem. Thomas Petrick for extensive experimental work in the laboratory. We are grateful to Vattenfall PowerConsult GmbH and Vattenfall Europe Generation AG for financial support of this work. Further, we thank Rohm and Haas France S.A.S., Bayer AG, Lanxess GmbH and Purolite for providing us with the anion exchange resins.