Enhancement of uranium recovery from seawater using amidoximated polymer gel synthesized from radiation-polymerization and crosslinking of acrylonitrile and methacrylic acid monomers

Abstract

The amidoximated polymer gel for uranium recovery from natural seawater was successfully synthesized from radiation-polymerization and crosslinking of acrylonitrile (AN) and methacrylic acid (MAA) monomers with N,N’-Methylene bisacrylamide (MBA) as the crosslink agent. The optimum condition to prepare the polymer gel is: the gamma ray dose of 40 kGy, the AN:MAA ratio of 80:20, and the crosslink agent concentration of 8 g/L. The polymer gel can be reused for at least 8 times without significant performance decrease. The kinetic of seawater absorption by the adsorbent was quite rapid, reaching the equilibrium swelling ratio of approximately 250% in about 30 min. By submersion of this polymer gel in the seawater sample with only 300 and 840 ppb of added uranium for 4 weeks, the adsorption capacity reached as much as 6.96 and 9.64 mg/g, respectively. By submersion of this polymer gel in the seawater sample with 30 and 2140 ppm of added uranium for 1 week, the adsorption capacity reached as much as 334 and 409 mg/g, respectively. This high-efficiency amidoxime polymer gel offers a possibility of being utilized as a seawater uranium recovery agent on an industrial scale. Suitable elution conditions to minimize mass loss as well as suitable locations with clear seawater and no algae growth will need to be identified. Moreover, the research outcome presents a novel environmental remediation process to adsorb uranium ions released into seawater following a nuclear accident.