Uranium elimination and recovery from wastewater with ligand chelation-enhanced electrocoagulation

Radioactive uranium discharged from terrestrial sources heterotrophic leaching has caused significant harm to the ecosystem and public health. Here, we report an electrocoagulation method enhanced by ligand chelation for removing and recovering uranium from wastewater. The anode material and chelate were optimized for treating bulk uranium-containing wastewater, and the uranium precipitation mechanism and recycling method were comprehensively investigated. With the optimized Fe anode and Alizarin S as chelate, uranium was removed efficiently within a short time to satisfy the emission regulation. After Alizarin S selectively captures the uranyl ions, the formed chelation complex will compress and encapsulate the flocculation precursor, minimizing its crystal growth and decreasing its interfacial charge to facilitate the precipitation. Uranium in the precipitated flocs was efficiently eluted with an oxidizing detergent, and the yellowcake heavy uranium amide was obtained by subsequent digestion of organics and ammonia precipitation. The overall uranium recovery efficiency was as high as 89.71%. This proposed scheme may be used for practical uranium elimination and recovery from wastewater.