摘要
高温加热可膨胀石墨制得膨胀石墨,用于去除溶液中的U(Ⅵ)。通过静态吸附实验,研究了初始p H、吸附剂投加量、U(Ⅵ)初始浓度、温度以及吸附时间对膨胀石墨吸附U(Ⅵ)效果的影响。实验结果表明,膨胀石墨吸附U(Ⅵ)的最佳p H为6.5,在温度为30℃,投加量为2.0 g/L,U(Ⅵ)初始质量浓度为10 mg/L时,对U(Ⅵ)的去除率达到98.08%,反应在4 h达到平衡。Langmuir等温吸附模型和准二级动力学模型较好地拟合了吸附过程,30℃时饱和吸附量为27.03 mg/g;热力学分析表明,膨胀石墨对U(Ⅵ)的吸附是自发的放热反应。比表面积测试、扫描电镜、X射线能谱与傅里叶红外光谱分析结果表明,膨胀石墨对U(Ⅵ)的吸附以物理吸附为主,表面官能团起辅助作用。解吸实验证明,膨胀石墨是可重复利用的吸附剂。
Expanded graphite（ EG） was prepared from expandable graphite at high temperature and used to adsorb uranium（ Ⅵ） ions from aqueous solutions. The effects of pH,adsorbent dosage,initial U（ Ⅵ） ion concentration,temperature,and adsorption time on adsorption of U（ Ⅵ） were investigated through static adsorption experiments. The results showed that the optimum adsorption occurs at a pH of 6. 5 and the adsorption reaches equilibrium within 4 h. Meanwhile,the removal rate was up to 98. 08% for an initial U（ Ⅵ） concentration of 10 mg / L and adsorbent dosage of 2. 0 g / L at 30 ℃. The adsorption process fit well with the Langmuir isotherm model and pseudo-second-order kinetic model,and the maximum adsorption capacity for U（ Ⅵ） ions was27. 03 mg / g. Thermodynamic study revealed that adsorption of U（ Ⅵ） on EG is primarily due to a spontaneous exothermic reaction. Brunauer-Emmett-Teller（ BET） surface area test,scanning electron microscopy（ SEM）-energy dispersive X-ray spectroscopy（ EDS）,and Fourier transform infrared（ FTIR） spectroscopy verified that physical adsorption is the main adsorption mechanism and surface functional groups play a supplementary role.Desorption experiments showed that EG is a reusable adsorbent.
出处
《环境工程学报》
CAS
CSCD
北大核心
2016年第3期1126-1132,共7页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(11175081
11475080)
高等学校博士点基金项目(20134324110003)
关键词
膨胀石墨
吸附
铀(Ⅵ)
解吸
expanded graphite（EG）
adsorption
uranium（Ⅵ）
desorption
