摘要
为探讨改性氧化石墨烯(GO)的性质特征对其吸附放射性重金属铀的影响,将L-谷氨酸(L-Glu)与氧化石墨烯发生亲核反应,从而制得L-谷氨酸功能化的氧化石墨烯(L-Glu/GO)。通过静态吸附试验,考察了p H值、投加量、反应时间、温度与铀初始质量浓度等因素对L-谷氨酸功能化氧化石墨烯吸附铀效果的影响,并采用扫描电镜(SEM)、X射线衍射(XRD)、红外光谱(FT-IR)对吸附剂的结构和形貌进行了表征,分析其吸附机理。结果表明,铀初始质量浓度为10mg/L,p H=4,投加量为0. 2 g/L时吸附效果最佳,吸附平衡时间为40 min,温度对吸附效果影响不大。吸附过程符合准二级动力学模型和Langmuir等温吸附方程,铀初始质量浓度为70 mg/L,30℃时最大吸附容量为309. 36 mg/g。L-Glu/GO的表征结果表明,L-谷氨酸上的氨基进攻GO上的环氧基团并与C发生了亲核取代反应,为GO引入了含氮基团,实现了GO的功能化。相比GO,L-Glu/GO的晶体结构发生了较大改变,L-Glu/GO吸附U(VI)后表面更光滑。
The present paper is aimed at identifying and determining the specific features of the modified graphene oxide and its effects on the adsorption of the radioactive uranium.At the same time,it has also been making efforts to dissolve L-glutamic acid(0.4 g)and potassium hydroxide(0.5 g)in 20 mL of deionized water,and then add the solution dropwisely to a beaker with 100 mL of 1 mg/mL GO solution,which tends to be dispersed ultrasonically and uniformly at the room temperature and then placed in a water bath at a temperature of 70℃for a disturbingly stirring reaction in a length of 24 hours.And,then,L-glutamic acid may tend to react with the graphene oxide under the alkaline conditions to produce the L-glutamic acid functionalized graphene oxide(L-Glu/GO).Through the static adsorption experiments,we have made an investigation of the effects of the pH value,the adsorbent dosage,the reaction time,the room temperature and the initial uranium concentration rate on the adsorption of uranium by L-Glu/GO.The structure and morphology of the adsorbent can then be evaluated and judged by way of scanning electron microscopy,X-ray diffraction and Fourier Transfirm infrared spectroscopy.And,afterwards,we have analyzed the mechanism of L-glutamic acid functionalized graphene oxide(L-Glu/GO)on the adsorption of U(VI),through which it has been made possible to determine the optimal adsorptive condition for U(VI).And,next,we can analyze the adsorption process from the point of view of dynamics and thermodynamics,which would be able to provide for a theoretical basis of the application of L-Glu/GO to the practical sewage treatment.The experimental results may also imply that the best adsorption effect can be achieved on the following conditions:When the dosage is 0.2 g/L,the initial concentration of uranium should be 10 mg/L at pH=4 for 40 min,though the temperature tends to have little influence on the adsorption result.Besides,the adsorption process of U(VI)by L-Glu/GO proves well fit for the quasi-secondary kinetic model and the
作者
李仕友
欧阳成炜
伍随意
王国华
周耀辉
谢水波
LI Shi-you;OUYANG Cheng-wei;WU Sui-yi;WANG Guo-hua;ZHOU Yao-hui;XIE Shui-bo(Hunan Provincial Key Laboratory of Pollution Control and Resources Technology,University of South China,Hengyang421001,Hunan,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2019年第1期231-238,共8页
Journal of Safety and Environment
基金
国家自然科学基金项目(11475080)
南华大学研究生科学基金项目(2018KYY118)
关键词
环境工程学
氧化石墨烯
铀
吸附
environmental engineering
graphene oxide
uranium
adsorption
