【作者】 盛国栋； 汤燕娜； 李益民； 王祥科； 黄宇营；

【Author】 Guodong Sheng;Yanna Tang;Yimin Li;Wang Xiangke;Yuying Huang;College of Chemistry and Chemical Engineering,College of Medical Science,Shaoxing University;School of Chemistry and Environment,North China Electric Power University;Shanghai Synchrotron Radiation Facility (SSRF),Shanghai Institute of Applied Physics,Chinese Academy of Sciences;

【机构】 绍兴文理学院化学化工学院； 华北电力大学环境与化学工程系； 中国科学院上海光源；

【摘要】 我们研究了粘土协同纳米铁对放射性核素的还原固定及微观作用机制。研究结果表明,粘土可以明显提高纳米铁对放射性核素的还原转化。荷正电的水滑石可以有效吸附Re(VII),Se(IV)/(VI),Cr(VI)等阴离子,而荷负电的硅藻土、高岭土可以有效吸附U(VI),Ni(II),Co(II)等阳离子,增强放射性核素在界面的富集,从而加速纳米铁对其的还原,在吸附和还原直接存在明显的协同作用。我们采用同步辐射XAFS技术对放射性核素还原固定的微界面过程进行了深入的研究,结果发现粘土可以促进纳米铁将毒性大,流动性强的高价态Re(VII),Se(IV)/(VI),Cr(VI),U(VI)还原转化为毒性小、难溶性的低价态Re(VI),Se(0)/(-II),Cr(III),U(IV)物质。此外,这些难溶性反应产物主要覆盖在粘土上,可以提高纳米铁的反应活性。我们运用穆斯堡尔谱深入揭示了反应中生产的亚铁可以吸附在固相上形成还原活性更高的吸附态亚铁,进一步促进对放射性核素的还原。更多还原

【Abstract】 Herein,we study the mechanism of the reduction and immobilization of radionuclides by clay and nanoiron.The research results show that the reduction and transformation of radionuclides by nanoiron can be improved obviously in the presence of clay.The positively-charged hydrotalcite can effectively adsorb anions(like Re(VII),Se(IV)/(VI),Cr(VI)),and the negatively-charged diatomite or kaolin can effectively adsorb cations(like U(VI),Ni(II),Co(II)).Namely,the enrichment of radionuclides at the interface was enhanced,thus accelerating the reduction of radionuclides by nanoiron,which is due to the good synergistic effect between adsorption and reduction.We further used synchrotron radiation XAFS technique to study the micro interfacial processes of the reduction of radionuclides.The results showed that clay can promote the reduction of high valence state Re(VII),Se(IV)/(VI),Cr(VI),U(VI) with high toxicity and solubility,into the low valence state Re(VI),Se(0)/(-II),Cr(III),U(IV) with low toxicity and less solubility.In addition,these insoluble reaction products mainly cover the clay,which can improve the reaction activity of nanoiron.We use the Mossbauer spectrum to reveal that the ferrous iron produced in the reaction can be adsorbed on the solid phase to form a higher reduction activity(i.e.,adsorbed ferrous iron),which further promotes the reduction of radionuclides.更多还原