Arsenic Removal from Water Using Various Adsorbents:
Magnetic Ion Exchange Resins, Hydrous Ion Oxide
Particles, Granular Ferric Hydroxide, Activated Alumina,
Sulfur Modified Iron, and Iron Oxide-Coated Microsand

Sinha, Shahnawaz; Amy, Gary; Yoon, Yeomin; Her, Namguk

doi:2011.16.3.165

Environmental Engineering Research 2011;16(3): 165-173. DOI: https://doi.org/10.4491/eer.2011.16.3.165

Arsenic Removal from Water Using Various Adsorbents: Magnetic Ion Exchange Resins, Hydrous Ion Oxide Particles, Granular Ferric Hydroxide, Activated Alumina, Sulfur Modified Iron, and Iron Oxide-Coated Microsand

Shahnawaz Sinha¹, Gary Amy¹, Yeomin Yoon², and Namguk Her³^†

¹Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal, 23955-6000, Saudi Arabia
²Department of Civil and Environmental Engineering, University of South Carolina, Columbia, SC 29208, USA
³Department of Chemistry and Environmental Sciences, Korea Army Academy at Young-Cheon, Yeongcheon, Cyeongbuk, 770-849, South

Corresponding Author: Namguk Her ,Tel: +82-54-330 4760, Fax: +82-54-335 5790, Email: namguk@daum.net

Received: February 25, 2011; Accepted: August 8, 2011.

ABSTRACT

The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated microsand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of C_eq = 10 μg/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95%.

Keywords: Adsorbents | Arsenic removal | Ion effect | Sorption | Water treatment