In this study, removal of 209Po from aqueous media using a natural zeolite as an adsorbent material was investigated. The adsorption experiments were performed by batch technique. The influence of specific process parameters such as initial concentration, pH of solution, contact time and temperature was studied to predict the optimum conditions for effective removing of 210Po. Initial and equilibrium activity concentration of 209Po in solutions was counted by a ZnS(Ag) alpha scintillation counter. Adsorption yield of 209Po onto the zeolite was determined as 90 ± 2% at pH: <3 and 25 °C for 40 min of contact time. The applications of the isotherm models such as Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms were studied to evaluate adsorption characteristics of 209Po onto natural zeolite. Results indicated that the Dubinin-Radushkevich and Freundlich models gave a better fit to the experimental data than Langmuir isotherm models. The thermodynamic parameters such as Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of adsorption process were calculated. The change in entropy (ΔSo) and enthalpy (ΔHo) were estimated to be -0.0003 J nmol-1 K-1 and 0.1008 kJ nmol-1, respectively.

中文翻译：

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从水生环境中去除209Po及其平衡和热力学参数。

在这项研究中，研究了使用天然沸石作为吸附材料从水性介质中去除209Po的方法。吸附实验采用间歇技术进行。研究了特定工艺参数（例如初始浓度，溶液的pH，接触时间和温度）的影响，以预测有效去除210Po的最佳条件。通过ZnS（Ag）α闪烁计数器对溶液中209Po的初始和平衡活性浓度进行计数。在pH值<3和25°C下接触40分钟，确定209Po在沸石上的吸附率为90±2％。研究了等温线模型（例如Langmuir，Freundlich和Dubinin-Radushkevich（DR）等温线）的应用，以评估209Po在天然沸石上的吸附特性。结果表明，与Langmuir等温线模型相比，Dubinin-Radushkevich和Freundlich模型对实验数据的拟合效果更好。计算了吸附过程的热力学参数，如吉布斯自由能（ΔG°），焓（ΔH°）和熵（ΔS°）。熵（ΔSo）和焓（ΔHo）的变化估计分别为-0.0003J nmol-1 K-1和0.1008 kJ nmol-1。