摘要
以经典的金属有机骨架(MOFs)材料ZIF-8为吸附剂,研究尺寸效应对铀吸附性能的影响。通过3种方法合成不同粒径的ZIF-8,利用扫描电子显微镜(SEM)、X射线粉末衍射仪(XRD)、表面积与孔隙度分析仪等对其进行了表征,测试了相同条件下不同尺寸的ZIF-8对硝酸铀酰溶液中U(Ⅵ)吸附,分别对其吸附过程的动力学和吸附等温线进行了考察,并测试了材料的可重复利用性。结果表明,成功制备了高结晶性、高纯度的ZIF-8,产物形貌呈菱形十二面体,颗粒均匀,粒径分别为约50 nm、150 nm及2μm;3种ZIF-8具有单一均匀的微孔结构和与粒径高度相关的比表面积;不同尺寸的ZIF-8均能快速吸附溶液中的U(Ⅵ),在室温pH=3下,在70 min左右时即可吸附初始质量浓度为200 mg/L的U(Ⅵ)溶液中90%以上U(Ⅵ);其中较小尺寸(约50 nm)的ZIF-8吸附性能最好,单位质量ZIF-8吸附U(Ⅵ)的饱和吸附量达到520.26 mg/g;ZIF-8对U的吸附动力学上符合二级动力学方程,吸附等温线符合Langmuir模型,说明ZIF-8对U(Ⅵ)的捕获属于化学单层吸附;经过4个吸附-解吸循环后,3种尺寸的ZIF-8均依然保持了70%以上的去除率。
ZIF-8,a classical metal-organic frameworks(MOFs)material,was used as an adsorbent to study the effect of particle size on its uranium adsorption performance.ZIF-8 particles with different sizes were synthesized by three methods,and characterized by scanning electron microscope(SEM),X-ray powder diffraction(XRD),surface area and porosity analyzer.The adsorption of ZIF-8 particles with different sizes for U(Ⅵ)from uranyl nitrate solution was tested under the same conditions.The parameters of adsorption isotherm and kinetics were calculated.The results show that ZIF-8 with high crystallinity and high purity is successfully prepared.The morphology of the product is rhombic dodecahedron,and the sizes of the particles are about 50 nm,150 nm and 2μm with narrow distributions.The three samples have single uniform micropore structures and their BET surface areas are highly related to the particle size.All the ZIF-8 particles with different sizes can quickly adsorb 90%of U(Ⅵ)from the initial concentration of 200 mg/L of U(Ⅵ)solution in 70 min(at room temperature,pH=3).The particles with smaller size(about 50 nm)show better adsorption performance,and the saturated adsorption capacity reaches 520.26 mg/g.The adsorption kinetics conforms to the second order kinetic equation,and the adsorption isotherm conforms to the Langmuir model,which indicate that the adsorption for U(Ⅵ)of ZIF-8 belongs to chemical monolayer adsorption.After 4 cycles of adsorption and desorption,their removal rates for U(Ⅵ)are still above 70%.
作者
田龙
豆维新
杨玮婷
王成
TIAN Long;DOU Wei-Xin;YANG Wei-Ting;WANG Cheng(State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;Key Laboratory of Advanced Materials of Tropical Island Resources,Ministry of Education,School of Science,Hainan University,Haikou 570228,China;Institute for New Energy Materials&Low-Carbon,Technologies Tianjin University of Technology,Tianjin,300384,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《应用化学》
CAS
CSCD
北大核心
2021年第1期84-91,共8页
Chinese Journal of Applied Chemistry
基金
国家重点研发计划(No.2017YFA0700104)
国家自然科学基金(No.21571170)
天津市自然科学基金(No.17JCZDJC000)资助。
