(663a) Engineered Magnetic Nanochains for Highly Efficient Arsenic Removal from Water

Arsenic-contaminated drinking water is a serious global health concern due to its high toxicity and carcinogenicity. The contamination in drinking water sources is estimated to affect over 144 million people around the world, spurring the development of numerous water treatment technologies to limit negative health impacts associated with exposure to arsenic contaminated water including cancer, skin lesions, and neurological disorders. These technologies include ion exchange, adsorptive media filtration, coagulation and flocculation, electrocoagulation, and anaerobic removal with iron sulfides. Recently, nanoparticles have been introduced as adsorbent media due to their superior efficiency compared to their bulk counter-parts. An efficient nanoadsorbent should ideally possess high surface area, be easy to synthesize, and most importantly offer a high arsenic removal capacity. Achieving all the important features in a single step synthesis is an engineering challenge. We have successfully engineered such a material in the form of nanochains synthesized via a one step flame synthesis. The ultra-long γ-Fe₂O₃ nanochains possess high surface area (151.12 m² g^-1), large saturation magnetization (77.1 emu g^-1) that aids in their gas phase self-assembly into long chains in an external magnetic field, along with an extraordinary arsenic removal capacity (162 mg.g^-1). A filter made with this material exhibited a relatively low-pressure drop and very little break-through of the iron oxide across the filter. A comparison of arsenic removal capacity with the materials reported in the literature and commercial adsorbent (Bayoxide E33) also demonstrated the high potential of efficient nanochains in arsenic removal from water.