Simultaneous removal of As(III) and organics in Fenton fluidized bed: The favorable co-crystallization of As(V) and Fe(III)

•Fenton fluidized bed (FFB) could remove As(III)/Fe(II) and organics simultaneously.•Slow As(III) but fast As(V) removal occurred on fluidizing iron-crystallized (IC) carriers.•Competitive complexion of As(V)/Fe(III) inhibited immobilizations on the IC carriers.•Recursive Fe(III) crystallization continuously provided essential surface OH groups for capturing As(V).•FFB showed effective As(V)/Fe(III) co-crystallization and COD removal in treating practical As(III) wastewater.