Background species effect on aqueous arsenic removal by nano zero-valent iron using fractional factorial design

► 26−2 fractional factorial design was employed to identify factors which affect arsenic removal by nanoiron process. ► The important species which play a significant role in removing arsenic were HA, PO43−, and Ca2+, with the first two species imposing inhibiting effect and the last one enhancing effect. ► The arsenic removal can be improved through pretreatment of PO43− and HA. ► The groundwater with high hardness, the nanoiron process can be an advantageous option.