Removal of Natural Organic Matter by Anion Exchange: Interactions, Selectivity, and EfficacyEPA Grant Number: F6A20031
Title: Removal of Natural Organic Matter by Anion Exchange: Interactions, Selectivity, and Efficacy
Investigators: Boyer, Treavor H.
Institution: University of North Carolina at Chapel Hill
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2006 through September 1, 2008
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2006) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Safer Chemicals , Fellowship - Environmental
Natural organic matter (NOM), a ubiquitous component of natural waters, is of concern because it poses water treatment challenges and health risks. Anion exchange technology has the potential to be an effective treatment process for the removal of NOM, but an improved understanding of anion exchange treatment is required. Accordingly, the objective of this research is to elucidate the interactions among NOM, competing inorganic anions, anion exchange resin, and solvent. The Specific Aims of this research are as follows:
- Evaluate a magnetic ion exchange resin for removal of NOM and inorganic anions on a continuous-flow pilot-scale basis
- Assess solute-resin and solute-solvent interactions for NOM removal by anion exchange
- Investigate the thermodynamics of NOM uptake by anion exchange
For Aim 1, an eight-month pilot plant study was conducted at a local water treatment plant. Currently, a mathematical model is being formulated to describe multicomponent anion exchange based on insights from the pilot plant study. Aims 2 and 3 will be accomplished through batch equilibrium experiments and continuous-flow mini-column experiments. Batch experiments will be used to obtain quantitative equilibrium information, such as selectivity coefficients, whereas mini-column experiments will be used to examine the selective removal of different NOM fractions and inorganic anions. Model waters containing well-characterized NOM extracts and macroporous, strong-base anion exchange resins with different polymer backbones will be used in this research.
It is expected that this research will improve anion exchange treatment for the removal of NOM, and allow for treatment to be tailored to the raw water characteristics, operating conditions, and treated water quality goals. Improved NOM removal by water utilities will have multiple benefits, such as reduced chemical requirements for downstream water treatment processes and decreased formation of halogenated organic disinfection byproducts.