金属有机骨架材料ZIF-67对甲基橙的吸附性能

Adsorption Properties of Methyl Orange by Metal Organic Framework ZIF-67

采用溶剂热法合成了金属有机骨架材料ZIF-67,并通过扫描电子显微镜(SEM)、X-射线粉末衍射(XRD)、傅里叶红外光谱(FT-IR)以及热重(TG)对其进行表征。将合成的ZIF-67用于水中甲基橙的吸附,系统地研究了pH、吸附剂质量、甲基橙初始质量浓度、接触时间和温度对吸附性能的影响。结果表明,当ZIF-67质量为20 mg、pH为7时,吸附效果最好;在303 K下吸附25 min达到平衡;在303 K下,ZIF-67对甲基橙的理论最大吸附量为152.67 mg/g。等温吸附数据符合Langmuir等温吸附模型,吸附动力学符合准二级吸附动力学模型,该吸附过程是一个自发的放热过程。乙醇可以对吸附后的ZIF-67较好地脱附,经过6次吸附-脱附循环仍保持较好的吸附效果。

Metal organic framework ZIF-67 has been successfully fabricated via solvothermal method.The as-synthesized ZIF-67 was characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray powder diffraction and thermogravimetric analysis.The adsorption property of ZIF-67 for methyl orange was investigated.The effects of pH value,dosage of adsorbent,initial concentration of methyl orange solution,contact time and temperature were discussed.The results show that the most proper dosage of ZIF-67 is 20 mg.When the pH value of the dye solution is 7,the adsorption capacity is the best.At 303 K,the adsorption reached an equilibrium within 25 min.The maximum adsorption capacity of ZIF-67 for methyl orange is 152.67 mg/g at 303 K.The isotherm data followed the Langmuir isotherm model and the kinetic adsorption obeyed the pseudo-second-order model.Thermodynamic parameters illustrated that the adsorption process is spontaneous and endothermic.The spent ZIF-67 has excellent regenerative performance by treating with ethanol,and the adsorption ability of ZIF-67 remains good after six adsorption-desorption cycles.