Esmaeili Abbas, Eslami Hadi
Occupational Environment Research Center, Department of Environmental Health Engineering, School of Health, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
MethodsX. 2019 Sep 10;6:1979-1985. doi: 10.1016/j.mex.2019.09.005. eCollection 2019.
The new Native Natural Bentonite (NNB) for adsorption of Pb() and Zn() ions from aqueous environments was investigated at 27 ± 1C by in batch laboratory experiments. Chemical and mineralogical structure of the NNB adsorbent was characterized by XRF and cation exchange capacity (CEC). The effect of pH, metals concentration, adsorbent dose, and agitation time were also studied. Langmuir and Freundlich isotherm and the Giles classification isotherm were used for describing the equilibrium data. The results show that the NNB contains silica (SiO) and alumina (AlO) as a major chemical compound. The maximum adsorption capacity (mg/g), based on Langmuir isotherm were 8.55 and 7.90 for Pb() and Zn(), respectively. Pb() and Zn() removal efficiency was increasing by increasing the initial pH of solutions, adsorbent dose, and contact time. Therefore, the results of this study show that the equilibrium is reached slowly (180 min), indicating the adsorption sites are not well exposed. By increasing the initial metals ion concentration, the capacity of adsorption decreased and the uptake of Pb() and Zn() per unit weight of the adsorbent (mg/g) increased. The adsorption efficiency of Pb() was higher than Zn().
通过批量实验室实验，在27±1℃下对用于从水环境中吸附Pb（Ⅱ）和Zn（Ⅱ）离子的新型天然膨润土（NNB）进行了研究。通过X射线荧光光谱（XRF）和阳离子交换容量（CEC）对NNB吸附剂的化学和矿物结构进行了表征。还研究了pH值、金属浓度、吸附剂剂量和搅拌时间的影响。使用朗缪尔等温线、弗伦德利希等温线和吉尔斯分类等温线来描述平衡数据。结果表明，NNB的主要化学成分是二氧化硅（SiO₂）和氧化铝（Al₂O₃）。基于朗缪尔等温线，Pb（Ⅱ）和Zn（Ⅱ）的最大吸附容量分别为8.55和7.90mg/g。通过提高溶液的初始pH值、吸附剂剂量和接触时间，Pb（Ⅱ）和Zn（Ⅱ）的去除效率提高。因此，本研究结果表明平衡达到缓慢（180分钟），表明吸附位点没有充分暴露。随着初始金属离子浓度的增加，吸附容量降低，单位重量吸附剂对Pb（Ⅱ）和Zn（Ⅱ）的吸附量（mg/g）增加。Pb（Ⅱ）的吸附效率高于Zn（Ⅱ）。
