Arsenite and chromate sequestration onto ferrihydrite, siderite and goethite nanostructured minerals: Isotherms from flow-through reactor experiments and XAS measurements.

•The sequestration of As(III), Cr(VI) and competitive As(III)-Cr(VI) on/in nanostructured minerals was reinvestigated.•The minerals have high potential to remove As and Cr from water.•As and Cr sorption isotherms were modelled with a Langmuir and Hill models.•As(III) was partially oxidized (up to 22%) in the competitive system with Cr(VI).•As(III) sorbed on ferrihydrite and goethite adopted edge and corner sharing geometries.