Nano-iron oxide coated on sand as a new sorbent for removal of arsenic from drinking water

Abstract

This study describes the removal of arsenic species including As(III) and As(V) from drinking water using magnetic iron oxide nanoparticles coated on sand (MIONCS). MIONCS was prepared by the batch method and characterized by a transmission electron microscope. The effects of different factors, pH on the synthesis of the adsorbent, contact time, amount of adsorbent, water sample volume, and adsorption capacity of MIONCS for arsenic removal were investigated. Under the optimum conditions, a 100% arsenic removal was achieved at pH value of 7 from a real drinking water with initial concentration of 87.0 μg L⁻¹ by MIONCS within 25 min. The Langmuir and Freundlich adsorption isotherms were investigated for a range of arsenic initial concentrations of 10–90 μg L⁻¹. Results suggest that the Langmuir isotherm is more adequate than the Freundlich isotherm in simulating the adsorption isotherm of arsenic. The adsorption capacity of the synthesized sorbent for arsenic calculated from Langmuir adsorption isotherms in batch experiments was 0.284 mg g⁻¹ (R² = 0.999), and the MIONCS adsorption rate constant is 502.2 L mg⁻¹. These findings indicate that the adsorption property of MIONCS has a great potential for arsenic removal from drinking water.

Keywords:

• Arsenic removal
• Drinking waters
• Magnetic iron oxide nanoparticles