Heterogeneous Fenton decontamination of organoarsenicals and simultaneous adsorption of released arsenic with reduced secondary pollution

Organoarsenicals are widely used as antibiotics in the livestock industry and largely discharged into water environment directly, their safe, efficient and cost-effective treatment are actively perused. Herein, a heterogeneous iron-based Fenton-like technology was designed and validated with much reduced secondary pollution, mainly attributed to the bi-functional properties of both Fenton-active and arsenic-affinitive iron oxides. This simple one-step strategy not only exhaustively degraded organoarsenicals, but also selectively adsorbed the released high-toxicity arsenic from treated water. With Roxarsone as target, the FeOOH-based Fenton-like system exhibited a much superior capacitie for both Roxarsone degradation and arsenic adsorption in various water matrices, compared to typical homogeneous systems under similar conditions. More than 80% of Roxarsone was degraded after 3.0 h, and most of the released AsO43- was removed simultaneously, without any additional post-treatment. The superior capacity of FeOOH might be mainly attributed to its strong redox-cycling capacity of surface central Fe atoms from their thermodynamically favorable electronic structure. Taking the important advantages of iron oxides and Fenton technology into account, our findings might provide a new chance to develop simple and efficient technologies for organoarsenicals removal from water with much reduced secondary pollution at a low cost.