Ultrahigh arsenic sorption using iron oxide-graphene nanocomposite supercapacitor assembly

In response to the increasing water demand, electro-sorption method has shown promise in context of high removal efficiency of metals with less energy consumption. Here, we report for the first time ultrahigh sorption capacity of iron oxide-graphene (Fe3O4-HEG) nanocomposite supercapacitor assembly for both inorganic arsenic species (arsenate and arsenite). Graphene has been synthesized by hydrogen induced exfoliation of graphitic oxide and decorated with iron oxide (Fe3O4) nanocrystals by chemical route. Electrochemical sorption behavior of nanocomposite electrodes for arsenic has been examined by cyclic voltammetry and kinetic studies. Adsorption isotherm models have been tested to calculate the maximum adsorption capacities (using Langmuir isotherm) for arsenate and arsenite and found to be nearly 172.1 and 180.3mg/g, respectively, using supercapacitor assembly. These values are higher than other adsorbents for arsenic. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4766455]