Removal of arsenate by cetyltrimethylammonium bromide modified magnetic nanoparticles

► As(V) adsorption capacity of Fe3O4@CTAB was 23.07 mg g−l. ► As(V) (100 μg L−1) can be removed with 0.1 g L−1 Fe3O4@CTAB within 2 min at pH 6. ► As(V) can be effectively removed with Fe3O4@CTAB in a wide pH range (from 3 to 9). ► NOM and competitive anions could not significantly inhibit As(V) adsorption. ► Fe3O4@CTAB could be regenerated with alkali solutions.