Enhanced removal of As(III)/(V) from water by simultaneously supported and stabilized Fe-Mn binary oxide nanohybrids

In this study, reduced graphene oxide (RGO) and different stabilizers (hexadecyltrimethylammonium bromide, starch, and carboxymethyl cellulose) were applied to simultaneously support and stabilize Fe-Mn binary oxide (FeMnO_x) nanohybrids, and enhanced removal of As(III)/(V) from water was achieved. TEM images shows that the aggregation of FeMnO_x on RGO was effectively inhibited after the starch stabilization, meanwhile, the loading of FeMnO_x on RGO was also increased. The adsorption capacity of As(III) and As(V) on starch-FeMnO_x/RGO via Langmuir isotherm model was 78.74 mg g⁻¹ and 55.56 mg g⁻¹, respectively, which was 1.99 and 2.39 times higher than bare FeMnO_x. The adsorption kinetics was well fitted by the pseudo-second-order model. The effects of initial pH and coexisted anions were investigated. Over 90% of As(III) and As(V) could be removed by starch-FeMnO_x/RGO during the five consecutive adsorption-desorption cycles. The results revealed the potential of the RGO supported and starch stabilized FeMnO_x as an efficient adsorbent for arsenic removal from water.