Abstract :
Bromide serves as a precursor for regulated disinfection byproducts in drinking water. For example, ozone reacts with bromide to form bromate, and chlorine reacts with bromide and natural organic matter (NOM) to form trihalomethanes and haloacetic acids. Therefore, finding effective methods for the removal of bromide (and NOM) from drinking water is of great importance. Activated carbon and ion exchange resin are two kinds of common drinking water treatment additives. The objectives of the research were to assess the effectiveness of (1) silver-impregnated activated carbons (SIACs) and (2) ion exchange (IX) resins for bromide removal. Three commercial SIACs with different silver concentrations and three anion IX resins, including a magnetic ion exchange (MIEX) resin, were investigated. Batch kinetic tests were conducted both with bromide-spiked laboratory water and Dan River water (Eden, NC). While SIACs removed up to 9% of bromide from laboratory water, SIACs did not produce measurable bromide removal from Dan River water. However, two of the three ion exchange resins effectively removed both bromide and NOM, as measured by total organic carbon (TOC). After a contact time of 60 minutes, one IX resin was able to remove 74% of bromide and 19% of TOC from Dan River water with a dose of 1 mL/L and >99% of bromide and 48% of TOC at a dose of 10 mL/L. The MIEX resin was somewhat less effective for bromide removal (42% at 1 mL/L, 90% at 10 mL/L) but more effective for TOC removal (43% at 1 mL/L, 64% at 10 mL/L).
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