In this work, the impact of iron species on the removal and reductive recovery of As(III) and As(V) through an iodide-enhanced UV/sulfite process was explored.The results showed that both Fe(II) and Fe(III) exhibited a dual effect on the arsenic removal process, characterized by simultaneous facilitative and inhibitory behavior.The facilitative effect dominated in the initial phase, while the inhibitory effect became more pronounced during the subsequent reaction.During the arsenic reduction process, a portion of Fe(II) underwent oxidation to Fe(III), which enhanced arsenic removal through surface complexation and coprecipitationMeanwhile, iron species, as transition metals, stimulated the generation of •OH and SO•-4 from sulfite, thereby inhibiting arsenic reductionFurthermore, the competitive absorption of UV light by iron species with sulfite, reduced the production of e-aq, which also inhibited arsenic reductionThe iron species not only affected the efficiency of arsenic reduction, but also the product distribution.The original product was primarily As(0), but under the influence of iron, the product became a mixture of As2O3 and As(0), accompanied by the formation of iron (hydr)oxides.This study offers insights into arsenic reduction and recovery from arsenic-rich wastewater.