Abstract
The removal of arsenic(III) and arsenic(V) from an aqueous solution through adsorption on to Fe(3)O(4), MnFe(2)O(4), 50% Mn substituted Fe(3)O(4), 75% Mn substituted Fe(3)O(4), and Mn(3)O(4) nanomaterials was investigated. Characterization of the nanomaterials using XRD showed only pure phases for Mn(3)O(4), MnFe(2)O(4), and Fe(3)O(4). The 50% and 75% substituted nanomaterials were found to be mixtures of Mn(3)O(4) and Fe(3)O(4). From batch studies the optimum binding pH of arsenic(III) and arsenic(V) to the nanomaterials was determined to be pH 3. The binding capacity for As(III) and As(VI) to the various nanomaterials was determined using Isotherm studies. The binding capacity of Fe(3)O(4) was determined to be 17.1 mg/g for arsenic(III) and 7.0 mg/g for arsenic(V). The substitution of 25% Mn into the Fe(3)O(4) lattice showed a slight increase in the binding capacity for As(III) and As(VI) to 23.8 mg/g and 7.9 mg/g, respectively. The 50% substituted showed the maximum binding capacity of 41.5 mg/g and 13.9 mg/g for arsenic(III) and arsenic(V). The 75% Mn substituted Fe(3)O(4) capacities were 16.7 mg/g for arsenic(III) and 8.2 mg/g for arsenic(V). The binding capacity of the Mn(3)O(4) was determined to be 13.5 mg/g for arsenic(III) and 7.5 mg/g for arsenic(V). In addition, interference studies on the effects of SO(2-)(4), PO(3-)(4), Cl(-), and NO(-)(3) investigated. All the interferences had very minimal effects on the As(III) and As(V) binding never fell below 20% even in the presence of 1000 ppm interfering ions.