乙二胺改性木屑黄原酸盐对水溶液中Cu（II）和Ni（II）离子吸附平衡及动力学

摘要

Sawdust xanthate modified with ethanediamine was used for the removal of Cu(II) and Ni(II) from aqueous solution. The influence of various operating parameters such temperature and adsorbent dosage on the adsorption isotherms of modified sawdust was investigated. Thermodynamic parameters, namely Gibbs free energy (∆GΘ), enthalpy (∆HΘ) and entropy (∆SΘ) of Cu(II) and Ni(II) adsorption process were calculated, showing that the adsorption is a spontaneous and exothermic process. The modified extended Langmuir equation approaches provide excellent prediction of the binary adsorption. In single and binary systems, the overall adsorption data were best described by the pseudo-second order kinetic model, then the calculated values of activation energy of Cu(II) and Ni(II) adsorption process were 59.12 and 55.92 kJ/mol respectively. The results show that the affinity of each metal ion onto the modified sawdust surface is influenced by the presence of the other one.%使用乙二胺改性的木屑黄原酸盐对水溶液中的Cu(II)、Ni(II)离子进行吸附。在单离子体系中，考虑影响因素(温度、投加量)对Cu(II)、Ni(II)单离子吸附等温线的影响；并计算Cu(II)、Ni(II)离子吸附的热力学参数：吸附吉布斯自由能(∆GΘ)、吸附过程的焓变(∆HΘ)以及熵变(∆SΘ)，表明此吸附是一个放热自发的过程。在 Cu(II)和Ni(II)双离子体系中，采用修正后的拓展Langmuir模型对体系的吸附情况可以进行很好的预测。在单离子体系和双离子体系中，吸附过程的数据均可通过准二级动力学模型进行描述；计算得到其对Cu(II)和Ni(II)单离子的吸附活化能分别为59.12和55.92 kJ/mol。结果表明，金属离子在改性木屑表面的吸附效果会受到另一离子存在的影响。