电子转移活化再生催化剂原子转移自由基聚合法制备吸附剂及其吸铀性能

为满足我国核电事业的发展需求，从海水中提取铀尤为重要。海水中约有45亿吨铀，约是陆地铀资源的千倍。偕胺肟基对铀酰离子有很强的络合能力及较高的选择性，是良好的铀酰离子吸附官能团，因此，偕胺肟基吸附剂的制备是海水提铀的关键步骤之一。以聚氯乙烯（PVC）为基材，通过电子转移活化再生催化剂原子转移自由基聚合（ARGET ATRP）方法合成偕胺肟基纤维吸附剂（PVC-AO），控制丙烯腈（AN）的用量，制得不同接枝率的吸附剂，用红外光谱分析表明，腈基成功转化为偕胺肟基，用扫描电镜观察不同接枝率吸附剂的表面形貌变化，并用制得不同接枝率吸附剂开展了不同实验温度、不同初始铀酰离子浓度和不同pH条件下的实验，探究了不同接枝率偕胺肟基吸附剂对铀吸附性能的影响。结果表明：偕胺肟基吸附剂吸附铀酰离子的最佳pH为5~6；随着吸附剂接枝率的增加，饱和吸附量和吸附速率均增加，接枝率为5 811%的吸附剂吸附量达到111 mg/g；但随着吸附剂接枝率增加，吸附剂表面产生的凝胶物质会阻碍吸附剂对铀酰离子的吸附。

Preparation of ARGET ATRP Adsorbents with Diffident Degree of Grafting and Their Uranium Uptake

Seawater is considered to be a major source of uranium with an estimated quantity of around 4.5 billion metric tons, which is nearly 1 000 times higher than that available in terrestrial ores. To satisfy the needs of Chinese nuclear power industry development, extracting uranium from seawater is particularly important. Amidoxime groups can extract uranyl ions efficiently with a strong complexation ability and high selectivity. Therefore, the preparation of adsorbents is the key to the extraction uranium from seawater. In this study, we developed effective adsorbent fibers for the recovery of uranium from seawater via electron transfer activated regeneration atom-transfer radical polymerization (ARGET ATRP) from a polyvinyl chloride (PVC) fiber, and we got the different degree of grafting adsorbent by controlling the amount of acrylonitrile. Fourier Transform Infrared Spectroscopy indicated the grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. Scanning electron microscopy was used to observe the surface morphologies of different degree of grafting adsorbent. The results showed that the optimum pH value of amidoxime adsorbents for the adsorption of uranyl ion was 5~6. With the increase of the degree of grafting of the adsorbent, the adsorption capacity and the adsorption rate were both increased, and the adsorption capacity of the adsorbent with the degree of grafting of 5 811% reached 111 mg/g. However, with the increase of the degree of grafting of the adsorbent, the gelling generated on the surface of the adsorbent hinders the adsorbent from adsorbing uranyl ions.