Adsorption of Hg(II) from an Aqueous Solution by Silica-Gel Supported Diethylenetriamine Prepared via Different Routes: Kinetics, Thermodynamics, and Isotherms

详细信息    查看全文

• 作者：Rongjun Qu ; Ying Zhang ; Changmei Sun ; Chunhua Wang ; Chunnuan Ji ; Hou Chen ; Ping Yin
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2010
• 出版时间：April 8, 2010
• 年：2010
• 卷：55
• 期：4
• 页码：1496-1504
• 全文大小：362K
• 年卷期：v.55,no.4(April 8, 2010)
• ISSN：1520-5134

文摘

The kinetics, thermodynamics, and isotherms of Hg(II) ion adsorption onto silica-gel supported diethylenetriamine adsorbents, SG-HE-dD, SG-HO-dD, SG-HE-pD, and SG-HO-pD (where SG means silica-gel; HE, heterogeneous; HO, homogeneous; d, direct; p, protection; and D, diethylenetriamine), prepared by so-called heterogeneous-direct amination, homogeneous-direct amination, heterogeneous end-group protection, and homogeneous end-group protection methods, respectively, were investigated. The results showed that the adsorption processes of Hg(II) ions followed well a pseudofirst-order model onto SG-HE-dD, SG-HO-dD, and SG-HE-pD, while a pseudosecond-order model was followed onto SG-HO-pD. Film diffusion might be dominated in the adsorption process of Hg(II) ions onto the four adsorbents. Thermodynamic analysis revealed that the adsorption behaviors of Hg(II) ions onto the four adsorbents were endothermic processes, resulting in higher adsorption capacities at higher temperature. The Langmuir, Freundlich, and Redlich−Peterson models were employed to fit the isothermal adsorption. The results revealed that the linear Langmuir, nonlinear Langmuir, and nonlinear Redlich−Peterson isotherm models are the best-fit models to predict the experimental data. Mercury ions adsorbed on four adsorbents were desorbed effectively at about 5 % thiourea/0.1 mol·L⁻¹ HNO₃, and the adsorption capacity of the SG-HO-dD and SG-HO-pD adsorbents can still be maintained at the (98 and 95) % level at the fifth cycles, respectively.