Regeneration of perchlorate (ClO4-)-loaded anion exchange resins by a novel tetrachloroferrate (FeCl4-) displacement technique.
Selective ion exchange is one of the preferred treatment technologies for removing low levels of perchlorate (ClO4-) from contaminated water because of its high efficiency and minimal impact on water quality through the addition or removal of chemicals and nutrients. However, the exceptionally high affinity of ClO4- for type I anion-exchange resins makes regeneration with conventional NaCl brine extremely difficult and costly for practical applications. The present study entails the development of a novel regeneration methodology applicable to highly selective anion-exchange resins. Tetrachloroferrate (FeCl4-) anions, formed in a solution of ferric chloride and hydrochloric acid (e.g., 1 M FeCl3 and 4 M HCl), were found to effectively displace Cl04- anions that were sorbed on the resin. A mass-balance analysis indicated that a nearly 100% recovery of ion-exchange sites was achieved by washing with as little as approximately 5 bed volumes of the regenerant solution in a column flow-through experiment There was no significant deterioration of the resin's performance with respect to ClO4- removal after repeated loading and regeneration cycles. Thus, the new methodology may offer a cost-effective means to regenerate ClO4- -loaded resins with improved regeneration efficiency, recovery, and waste minimization in comparison with conventional brine regeneration techniques.
Gu
B
B
Environmental Sciences Division, Oak Ridge National Laboratory, Tennessee 37831, USA. gubl@ornl.gov
Brown
G M
GM
Maya
L
L
Lance
M J
MJ
Moyer
B A
BA
D000837:Anion Exchange Resins / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D017606:Chlorine Compounds / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D010472:Perchlorates / Q000737:chemistry*; D017670:Sodium Compounds / Q000737:chemistry*; D014874:Water Pollutants, Chemical; D014876:Water Pollution / Q000517:prevention & control*
D000837:Anion Exchange Resins; D017606:Chlorine Compounds; D005290:Ferric Compounds; D010472:Perchlorates; D017670:Sodium Compounds; D014874:Water Pollutants, Chemical; C031068:sodium perchlorate