摘要
为了解木纤维对铀的吸附特性,通过静态吸附实验,研究了木纤维的粒度、吸附时间、用量、温度及溶液的pH值和初始浓度等因素对模拟含铀废水中U(Ⅵ)去除率的影响,并从热力学和动力学方面对吸附过程进行了分析。结果表明:溶液初始pH≈3时,木纤维对铀的吸附平衡时间为4h,且吸附剂粒径越小、温度越高、用量越大,越有利于铀的去除;铀在木纤维上的吸附过程符合Langmuir等温吸附方程,吸附动力学过程可用准二级吸附动力学模型描述,表明化学吸附主要受动力学控制;木纤维吸附铀是自发的吸热反应。SEM、FT-IR和EDS分析结果表明,木纤维吸附铀后表面形态发生了改变,且在吸附过程中铀主要与木纤维表面活性基团螯合并形成配合物,存在表面络合吸附行为;吸附铀前后的能谱对比分析表明,吸附过程中存在离子交换行为。因此,木纤维对铀的吸附机理是以离子交换和表面络合吸附为主、物理吸附为辅的混合吸附过程。
The adsorption performance of uranium on wood fiber was studied with static experiment.The influence factors on the U（Ⅵ）removal rate such as wood fiber particle size,adsorption time, dosage,temperature, pH and initial concentration were researched,and the adsorption process was analyzed in terms of thermodynamics and kinetics.The results show that the adsorption equilibrium time is 4hours.When the pH reaches 3for uranium-containing wastewater,uranium can be removed with the decrease of the size of adsorbent and with the increase of adsorbent dosage and temperature.The equilibrium adsorption data fit to Langmuir isotherms.The kinetic analysisshows that the adsorption rate is mainly controlled by chemical adsorption.The adsorption process can be described by an equation of pseudo 2nd-order model.The thermodynamic data indicate that the synergistic uranium bio-sorption by wood fiber is a spontaneous and endothermal adsorption process.The adsorption mechanism was analyzed with SEM,FT-IR and EDS.The results show that the surface form of wood fiber is changed and uranium mainly chelates with active groups on the fiber＇s surface and forms the complexes.These indicate that the adsorption of uranium should be of surface coordination.The analyses of EDS before and after adsorption of uranium prove that the behavior of adsorption is ion exchange.The above results indicate that the adsorption mechanism is mainly surface coordination and ion exchange adsorption,followed by physical absorption.
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2015年第2期263-272,共10页
Atomic Energy Science and Technology
基金
国家自然科学基金资助项目(41402248)
四川省教育厅科技创新团队资助项目(12zd1106)
固体废物处理与资源化教育部重点实验室基金资助项目(12zxgk11)
非金属复合与功能材料重点实验室基金资助项目(11zxfk06)
核废物与环境安全国防重点学科实验室团队基金资助项目(13zxnk08)
关键词
木纤维
铀
吸附性能
吸附行为
吸附机理
wood fiber
uranium
adsorption performance
adsorption behavior
adsorption mechanism
