摘要
研究含铜水溶液中Sb(Ⅲ)和Fe(Ⅱ)离子在Purolite S957(一种可商购的阳离子交换吸附剂)上的竞争吸附机理。使用含有单离子或多离子的硫酸铜水溶液,采用固定吸附和间歇吸附技术,研究吸附过程对p H、树脂质量、接触时间和温度变化的敏感性,确定获得最大离子去除率的最佳参数范围。利用非线性回归技术,将单离子吸附实验数据用Henry、Langmuir、Freundlich、Temkin和Dubinin-Radushkevich等温线模型进行拟合。Sb(Ⅲ)的Freundlich等温线以及Fe(Ⅱ)溶液的Freundlich和Henry等温线对吸附平衡数据的拟合最好;而对于二元离子电解质,扩展的Freundlich模型对实验数据的拟合令人满意。描述吸附过程的动力学模型为准一级模型,说明物理吸附在吸附过程中的主导作用。吸附过程的热力学参数揭示单离子体系和含Sb(Ⅲ)-Fe(Ⅱ)电解质中Sb(Ⅲ)吸附机理的差异。Sb(Ⅲ)单独吸附为吸热过程,而Sb在Sb-Fe体系中的吸附为放热过程。
The present study dealt with the mechanism of competitive adsorption of Sb(Ⅲ)and Fe(Ⅱ)ions from a copper-containing aqueous solution on Purolite S957,a commercially available cationic ion-exchange adsorbent.Experiments were conducted using aqueous copper sulfate solutions containing either single or conjoint ions,using both sedentary and batch adsorption techniques to ascertain the sensitivity of the adsorption process to variation in p H,mass of resin,contact time,and temperature as well as establishing the optimal range of variables for maximum ion removal.The data from single ion adsorption tests were fitted by non-linear regression techniques to Henry,Langmuir,Freundlich,Temkin,and Dubinin–Radushkevich isotherm models.Freundlich isotherm for Sb(Ⅲ)and Freundlich and Henry models for Fe(Ⅱ)solutions best express the adsorption equilibrium data;while for binary ion electrolytes,the extended Freundlich model fitted the data satisfactorily.The kinetic model adequately describing adsorption was shown to be the pseudo-first-order,underscoring the dominant role of physical adsorption playing in the process.Thermodynamic parameters for the adsorption process reveal differences in the Sb(Ⅲ)adsorption mechanism from single ion and Sb(Ⅲ)-Fe(Ⅱ)containing electrolytes.The adsorption of Sb(Ⅲ)alone is endothermic,whereas the process becomes exothermic in the Sb(Ⅲ)-Fe(Ⅱ)system.
基金
the Sarcheshmeh Copper Complex-Iran,for financial support.
