Chen Hao, Zhao Yaogang, Wang Aiqin
Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
J Hazard Mater. 2007 Oct 22;149(2):346-54. doi: 10.1016/j.jhazmat.2007.03.085. Epub 2007 Apr 4.
A series of activated palygorskite clay by HCl with different concentrations was prepared and applied as adsorbents for removal of Cu(II) from aqueous solutions. The effects of contact time, adsorbent dosages and pHs of suspension on the adsorption capacities for Cu(II) were investigated. The results showed that adsorption capacity of activated palygorskites increased with increasing the HCl concentration and the maximum adsorption capacity with 32.24 mg/g for Cu(II) is obtained at 12 mol/L of HCl concentration. The variations in IR spectra and pH of solution after adsorption Cu(II) confirmed that the numerous amount of silanol groups (Si-OH) originated by acid treatment were mainly responsible for Cu(II) adsorption onto acid-activated palygorskite. Kinetic studies indicated that the adsorption mechanisms in the Cu(II)/acid-activated palygorskite system followed the pseudo-second-order kinetic model with a relatively small contribution of film diffusion. Equilibrium data fitted well with Freundlich isotherm model compared to Langmuir isotherm model, indicating that adsorption takes place on heterogeneous surfaces of the acid-activated palygorskite. Adsorption-desorption studies presented that activated palygorskite has lower adsorption and desorption efficiencies using Cu(CH3COO)2 than that of other inorganic copper salts, such as CuSO4, Cu(NO3)2, and CuCl2.
制备了一系列不同浓度盐酸活化的坡缕石粘土，并将其用作从水溶液中去除Cu(II)的吸附剂。研究了接触时间、吸附剂用量和悬浮液pH值对Cu(II)吸附容量的影响。结果表明，活化坡缕石的吸附容量随盐酸浓度的增加而增大，在盐酸浓度为12 mol/L时，对Cu(II)的最大吸附容量为32.24 mg/g。吸附Cu(II)后溶液的红外光谱和pH值变化证实，酸处理产生的大量硅醇基（Si-OH）是酸活化坡缕石吸附Cu(II)的主要原因。动力学研究表明，Cu(II)/酸活化坡缕石体系中的吸附机制遵循准二级动力学模型，膜扩散的贡献相对较小。与Langmuir等温线模型相比，平衡数据与Freundlich等温线模型拟合良好，表明吸附发生在酸活化坡缕石的非均相表面上。吸附-解吸研究表明，使用醋酸铜时，活化坡缕石的吸附和解吸效率低于其他无机铜盐，如硫酸铜、硝酸铜和氯化铜。
