Kyziol-Komosinska Joanna, Pająk Magdalena, Dzieniszewska Agnieszka, Panek Rafal
Institute of Environmental Engineering, Polish Academy of Sciences, 41-819 Zabrze, 34 M. Skłodowskiej-Curie Street, Zabrze, Poland.
Faculty of Civil Engineering and Architecture, Lublin University of Technology, 40 Nadbystrzycka Street, Lublin, 20-618, Poland.
Sci Rep. 2025 Mar 24;15(1):10125. doi: 10.1038/s41598-025-94903-4.
Adsorption of Cd(II) on synthetic Na-X zeolite was studied by batch method and compared with that on clinoptilolite and bentonite. The study examined the effects of contact time (2.5-1440 min), pH (3.0 and 5.0), anion type (Cl⁻, SO₄²⁻), and initial Cd(II) concentration (0.1-950 mg/L) on adsorption capacity. Adsorption data were fitted to Freundlich, Langmuir, Dubinin-Radushkevich, and Sips isotherm models, as well as pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. The highest adsorption occurred at pH 5.0 in the presence of sulphate ions, while the lowest - at pH 3.0 in the presence of chloride ions. The maximum adsorption capacity followed the trend Na-X (185-268 mg/g) > > bentonite (97-136 mg/g) > clinoptilolite (55-68 mg/g). The PFO model fit well for low Cd(II) concentrations and short contact times, whereas the PSO model described adsorption across all conditions. Binding strength, evaluated using the BCR extraction method, showed that Cd(II) was weakly and reversibly bound in fractions E1 and E2. The study concludes that synthetic Na-X zeolite is a highly effective adsorbent for removing Cd(II) from acidic wastewater, demonstrating significant potential for environmental applications.
采用分批法研究了合成Na-X沸石对Cd(II)的吸附，并与斜发沸石和膨润土进行了比较。该研究考察了接触时间（2.5 - 1440分钟）、pH值（3.0和5.0）、阴离子类型（Cl⁻、SO₄²⁻）和初始Cd(II)浓度（0.1 - 950 mg/L）对吸附容量的影响。吸附数据拟合了Freundlich、Langmuir、Dubinin-Radushkevich和Sips等温线模型，以及伪一级（PFO）和伪二级（PSO）动力学模型。在硫酸根离子存在下，pH值为5.0时吸附量最高，而在氯离子存在下，pH值为3.0时吸附量最低。最大吸附容量遵循以下趋势：Na-X（185 - 268 mg/g）＞＞膨润土（97 - 136 mg/g）＞斜发沸石（55 - 68 mg/g）。PFO模型适用于低Cd(II)浓度和短接触时间，而PSO模型描述了所有条件下的吸附情况。使用BCR萃取法评估的结合强度表明，Cd(II)在E1和E2组分中以弱结合且可逆的方式存在。研究得出结论，合成Na-X沸石是从酸性废水中去除Cd(II)的高效吸附剂，在环境应用中具有巨大潜力。
