New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate

Type
Article

Authors
Chubar, Natalia

KAUST Grant Number
KUK-C1-017-12

Date
2011-12

Abstract
Highly selective materials and effective technologies are needed to meet the increasingly stronger drinking water standards for targeted ionic species. Inorganic ion exchangers based on individual and mixed-metal hydrous oxides (or mixed adsorbents that contain inorganic ion exchangers in their composition) are adsorptive materials that are capable of lowering the concentrations of anionic contaminants, such as H 2AsO 4 -, H 3AsO 3, F -, Br -, BrO 3 -, HSeO 4 -, HSeO 3 - and H 3BO 3, to 10 μg/L or less. To achieve a higher selectivity towards arsenate, a new ion exchanger based on Mg-Al hydrous oxides was developed by a novel, cost-effective and environmentally friendly synthesis method via a non-traditional (alkoxide-free) sol-gel approach. The exceptional adsorptive capacity of the Mg-Al hydrous oxides towards H 2AsO 4 - (up to 200 mg[As]/gdw) is due to the high affinity of this sorbent towards arsenate (steep equilibrium isotherms) and its fast adsorption kinetics. Because of the mesoporous (as determined by N 2 adsorption and SEM) and layered (as determined by XRD and FTIR) structure of the ion-exchange material as well as the abundance of anion exchange sites (as determined by XPS and potentiometric titration) on its surface the material demonstrated very competitive (or very high) removal capacity towards other targeted anions, including fluoride, bromide, bromate, selenate, selenite, and borate. © 2011 IWA Publishing.

Citation
Chubar N (2011) New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate. Water Science & Technology: Water Supply 11: 505. Available: http://dx.doi.org/10.2166/ws.2011.080.

Acknowledgements
The research is funded by a King Abdullah University of Science and Technology (KAUST) (www.kaust.edu.sa) Center-in-Development Award to Utrecht University (No KUK-C1-017-12) via the KAUST Global Research Partnership program, which resulted in the formation of the Center for Soil, Water and Coastal Resources (SOWACOR) at Utrecht University: www.sowacor.nl.

Publisher
IWA Publishing

Journal
Water Science & Technology: Water Supply

DOI
10.2166/ws.2011.080

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