A new class of stabilized Fe-Mn binary oxide nanoparticles was prepared with a water-soluble starch or carboxymethyl cellulose (CMC) as a stabilizer. The nanoparticles were characterized and tested with respect to sorption of As(III) and As(V) from water and for immobilization of As(III) in soil. While arsenic sorption capacities were comparable for bare, or stabilized Fe-Mn nanoparticles, the particle stabilization enabled the nanoparticles to be delivered into soil for in situ immobilization of As(III). High As(III) sorption capacity was observed over a broad pH range of 5-9. Column breakthrough tests demonstrated soil mobility of CMC-stabilized nanoparticles. Once delivered, the nanoparticles remain virtually immobile in soil under typical groundwater conditions. When an As(III)-laden soil was treated with CMC-stabilized Fe-Mn, the water leachable arsenic was reduced by 91%-96%, and the TCLP leachability was reduced by 94%-98%. Consequently, As(III) is immobilized as the nanoparticles are immobilized in the soil.

Removal and immobilization of arsenic in groundwater using a new class of polysaccharide stabilized Fe-Mn oxide nanoparticles

244th National Meeting (2012)

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