Simultaneous removal of Cd(II) and Sb(V) by Fe–Mn binary oxide: Positive effects of Cd(II) on Sb(V) adsorption

•Fe–Mn binary oxide achieves the simultaneous removal of Cd(II) and Sb(V).•Cd(II) at above 0.25mmol/L improves Sb(V) adsorption onto FMBO.•Cd(II) improves more significant Sb(V) adsorption than Ca2+ and Mn2+.•Sb(V) adsorption decreases whereas Cd(II) adsorption increases with elevated pH.•The increased ζ-potential and Cd(II)–Sb(V) precipitation favors Sb(V) adsorption.