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Recently, the allowable concentration of arsenic in drinking water has been lowered by theUS Environmental Protection Agency (USEPA) from 50 ug/L to 10 ug/L. To meet this challenge, water utilities may soon be required to consider existing as well as innovative technologies for effectively removing arsenic. The treatment technology evaluated as part of this study includes evaluation of a novel adsorbent against several innovative adsorbent materials for arsenic removal. Novel adsorbent materials designated herein are materials that have been extensively studied in the past for arsenic removal, which includes activated alumina (AA) and ion-exchange resins, whereas innovative adsorbents are those materials that are still in development stages or have been successfully evaluated and tested for the removal of other types of contaminants (e.g., DOC, phosphate, etc.), but not yet evaluated for arsenic removal. Innovative adsorbents evaluated in this bench-scale study include: magnetically impregnated ion-exchange resins (MIEX), hydrous iron oxide particles (HIOPs), granular ferric hydroxide (GFH), sulfur-modified iron (SMI), and iron oxide coated microsands (IOC-M). These adsorbents were first evaluated in synthetic (using Milli-Q, carbon and ion free, water) and later in natural (surface and ground) waters for arsenic removal. Synthetic water studies were performed to avoid matrix effects and also to carefully study the effects of various anions and pH, and to relate this information to natural water systems to elucidate the effects of the water quality matrix on their performance for arsenic removal. A detailed characterization of these adsorbent materials in terms of their physico-chemical properties was also performed, which included determining their dry weight, metal content, particle size distribution, surface area, crystalline structure, surface charge (i.e., pHPZC) and texture determination. The systematic approach undertaken, (i.e., adsorbent characterization and evaluation in both synthetic and natural waters) proved to be an effective scheme in relating adsorbent performances (kinetics, capacities) to adsorbent characteristics in removing arsenic. Includes 9 references, tables, figure.

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Edition: Vol. - No. Published: 11/01/2002 Number of Pages: 13File Size: 1 file , 310 KB