3rd UF Water Institute Symposium Abstract

Submitter's Name Katrina Indarawis
Session Name Posters - Water Treatment and Aquatic Chemistry
Category Water Chemistry
Poster Number 83
Author(s) Katrina Indarawis,  University of Florida (Presenting Author)
  Treavor Boyer,  University of Florida
  Combined Ion Exchange Pretreatment to Reduce Membrane Fouling: Understanding Fundamental Chemistry During Ion Exchange Reactions
  Membrane technology is expected to play a critical role in future water treatment design due to the depletion and degradation of existing water sources. Limitations to these technologies are (1) fouling and scaling due to natural organic matter (NOM) and alkaline earth metals, and (2) membrane concentrate management. This research focuses on the removal of NOM and alkaline earth metals as a pretreatment to reduce fouling, and the treatment of membrane concentrate for recycle. The goal is to understand the behavior and relationships between NOM and alkaline earth metals using cation exchange reactions, and then evaluate those relationships during combined ion exchange reactions. A novel approach used in this research is the use of cation exchange as a tool to understand the behavior of the ions in solution with NOM by varying the mobile counter ion on a cationic magnetic exchange resin (MIEX). Stoichiometry of all cation exchange reactions will be compared to stoichiometry of combined ion exchange. A major result was that NOM, a negatively charged molecule, was removed with a cation exchange resin. This was due to NOM-metal complexation (including complexation with iron oxide exposed from the MIEX). Other results showed sulfate was reactive during these experiments due to precipitation of barium sulfate. The dissolved organic carbon (DOC) removal was relatively the same for each water with hardness (regardless of the calcium to magnesium ratio); however, there was significantly less DOC removed in the abscence of these cations. This phenomenon was observed with two NOM isolates. This work provides new knowledge about NOM-metal complexation with alkaline earth metals during cation exchange reactions and increases understanding of water chemistry during combined ion exchange reactions. This new knowledge will be applied in future experiments to decrease membrane fouling and be used in an innovative approach for treatment of membrane concentrate.