▎ 摘　　要

NOVELTY - A radioactive cobalt removing method involves adding expandable graphite in a concentrated sulfuric acid in a reaction container to obtain a mixture. The mixture is placed in an ice water bath, followed by adding potassium permanganate and graphite. The ice bath is withdrawn after the completion of reaction. The resultant product in the ice bath is stirred by adding deionized water and hydrogen peroxide to obtain mixed product. The mixed product is filtered, followed by discarding supernatant, which is mixed with hydrochloric acid and distilled water to obtain oxidized graphene. USE - Method for removing radioactive cobalt using graphene load nano-zero-valent iron composite material. ADVANTAGE - The method enables removing the radioactive cobalt with improved selectivity and improved absorption capacity of the composite material. DETAILED DESCRIPTION - A radioactive cobalt removing method involves adding 1-2 g expandable graphite in a concentrated sulfuric acid in a reaction container to obtain a mixture. The mixture is placed in a ice water bath, followed by adding potassium permanganate and graphite at a mass ratio of 1.5:1-6:1, and maintaining temperature of a reaction system at a less than 15 degrees C. The ice bath is withdrawn after the completion of reaction. The resultant product in the ice bath is stirred for 3 days at a constant temperature of 34-36 degrees C, adding 40 ml deionized water for three times and stirring at 59-61 degrees C for 30-60 minutes. The resultant product is stirred with 40 ml water at 89-91 degrees C for 30-60 minutes, and stirred with 40 ml deionized water and 30% hydrogen peroxide to obtain mixed product. The mixed product is filtered, when the mixed product is hot at 10000-12000 rpm for 30 minutes, followed by discarding supernatant. The supernatant is mixed with hydrochloric acid and distilled water to obtain oxidized graphene. The oxidized graphene is freeze-dried and dispersed in de-ionized water ultrasonically, followed by adding iron sulfate heptahydrate solution, filling argon gas, dropping potassium borohydride solution, blowing argon, maintaining reaction process under oxygen-free status, carrying out reaction for 1-2 hours, washing using de-ionized water and absolute ethyl alcohol to obtain reacted product. The reacted product is centrifuged and dried under vacuum to obtain graphene load nano-zero-valent iron composite material having zero-valent iron and graphene oxide at a ratio of 1:4-4:1. The resultant composite material is added to wastewater containing radionuclides 60cobalt, heated and vibrated to remove radioactive cobalt, where the mass ratio of concentrated sulfuric acid and graphite is 70:1-200:1, and the volume ratio of the potassium borohydride solution and iron sulfate heptahydrate solution is 1:1-25:1.