Perchlorate (ClO4 -) is a persistent contaminant found in drinking groundwater sources in the United States. Ion exchange (IX) with selective and disposable resins based on cross-linked styrene divinylbenzene (STY-DVB) beads is currently the most commonly utilized process for removing low concentrations of ClO4 - (10-100 ppb) from contaminated drinking water sources. However, due to the low exchange capacity of perchlorate-selective STY-DVB resins (∼0.5-0.8 eq/L), the overall cost becomes prohibitive when treating groundwater with higher concentration of ClO4 - (e.g., 100-1000 ppb). In this article, we describe a new perchlorate-selective resin with high exchange capacity. This new resin was prepared by alkylation of branched polyethyleneimine (PEI) beads obtained from an inverse suspension polymerization process. Batch and column studies show that our new PEI resin with mixed hexyl/ethyl quaternary ammonium chloride exchange sites can selectively extract trace amounts of ClO4 - from a makeup groundwater (to below detection limit) in the presence of competing ions. In addition, this resin has a strong-base exchange capacity of 1.4 eq/L, which is 1.75-2.33 times larger than those of commercial perchlorate-selective STY-DVB resins. The overall results of our studies suggest that branched PEI beads provide versatile and promising building blocks for the preparation of perchlorate-selective resins with high exchange capacity. © 2012 American Chemical Society.
|Original language||English (US)|
|Number of pages||9|
|Journal||Environmental Science & Technology|
|State||Published - Sep 20 2012|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This research was carried out at the California Institute of Technology and AquaNano, LLC. Selected materials characterization studies (FT-IR and SEM) were carried out at the Korea Advanced Institute of Science and Technology (KAIST). Funding for this research was provided by the U.S National Science Foundation (NSF) [CBET Award 0506951]. M. S. Diallo and D. P. Chen were supported by the KAIST EEWS Initiative (NT080607C0209721). W. A. Goddard III was supported partially by the KAIST World Class University (WCU) program (NRF-31-2008-000-10055).
ASJC Scopus subject areas
- Environmental Chemistry