天然水体中铀分离回收对非常规铀资源开发具有重要意义.本工作合成了一种新型聚丙烯腈/Hummers氧化莲房碳复合材料,考察其在弱碱性条件下于U(Ⅵ)-CO3体系中对U(Ⅵ)吸附行为.静态吸附实验表明,室温下、pH=8.0、ρ(U(Ⅵ))=50 mg/L、cT(CO3)=2 mmol/L 时,复合材料在 840 min 达到最大吸附容量约 51.92 mg/g.pH值、钙离子浓度、镁离子浓度、氟离子浓度和碳酸盐浓度增加会抑制U(Ⅵ)吸附.热力学分析表明,吸附过程主要为自发吸热的化学吸附.表征分析结果证实了复合材料对U(Ⅵ)吸附的结构稳定性,其表面—OH和—COOH(C=O)为主要U(Ⅵ)吸附位点.钙/镁离子存在下,U(Ⅵ)在复合材料上的吸附亲和力顺序为:Mg-U(Ⅵ)-CO3体系＞Ca-U(Ⅵ)-CO3体系.本工作研究结果有助于对天然含铀水体中铀的分离和提取提供新材料和新方法.
Abstract
The separation and recovery of uranium from natural water is of great significance to the exploitation of unconventional uranium resources.In our paper,a novel polyacrylonitrile(PAN)/Hummers oxidized lotus seedpod carbon composite was prepared,and adsorption of U(Ⅵ)ion from U(Ⅵ)-CO3 solution under weakly alkaline condition was also studied.Batch adsorption experimental results show that at room temperature,pH=8.0,ρ(U(Ⅵ))=50 mg/L,cT(CO3)=2 mmol/L,the adsorption reaches equilibrium after 840 min,and the maximum adsorption capacity is about 51.92 mg/g.The increase of the pH values,calcium ion concentration,magnesium ion concentration and carbonate concentration inhibit the U(Ⅵ)adsorption.Thermodynamic results indicate that it is a spontaneous,endothermic chemical adsorption process.Characterization results show that the composite displays good structure stability during U(Ⅵ)adsorption process,meanwhile,the phenolic—OH and—COOH(C=O)are the main adsorption sites on the composite surfaces.In the presence of calcium/magnesium ions,the order of adsorption affinity of U(Ⅵ)on the composite material is as follows:Mg-U(Ⅵ)-CO3 system＞Ca-U(Ⅵ)-CO3 system.The results can provide the new materials for the separation and extraction of uranium from natural uranium-containing water.
关键词
聚丙烯腈/Hummers氧化/莲房碳/U(Ⅵ)吸附/U(Ⅵ)-CO3体系
Key words
polyacrylonitrile/Hummers oxidation/lotus seedpod carbon/U(Ⅵ)adsorption/U(Ⅵ)-CO3 system
维普
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