Abstract Metformin (MET) is one of the anti-diabetic drugs which is widely used in the world and found abundantly in pharmaceutical wastewater. The purpose of this study, the adsorption of MET from aqueous solution by Fe-ZSM-5 (Fe-Z) zeolite as an adsorbent. The zeolite characterization was analyzed using FTIR, FE-SEM, TEM, XRD, and N2 adsorption-desorption Techniques. The adsorption was performed in a batch system, and the effect of parameters such as solution pH, initial concentration of MET, adsorbent dose, temperature, and contact time was investigated to optimize the adsorption process. Adsorption isotherms were studied by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models. The Langmuir model with a high correlation coefficient (R2 = 0.999) and the maximum monolayer adsorption capacity (qmax = 14.992 mg g−1) at T = 25 °C showed the highest consistent with MET adsorption on the Fe-Z zeolite. The kinetic data were best represented by the pseudo-second-order model. Also, thermodynamic parameters such as enthalpy changes (ΔH ), Gibbs energy changes (ΔG ), and entropy changes (ΔS ) were investigated. The highest adsorption efficiency was 95.7% at the optimum operating conditions: pH = 8.33, t = 25 °C, 1.1 g L−1 Fe-Z and C0 = 10 mg L−1. The developed nano-adsorbent had high reusability including only 4.4% drop in the removal efficiency. The results showed that the Fe-Z zeolite could be a promising adsorbent for the MET removal.

中文翻译：

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Fe-ZSM-5 纳米吸附剂从水溶液中吸附二甲双胍：等温线、动力学和热力学研究

摘要 二甲双胍(Metformin, MET)是世界范围内应用广泛、大量存在于制药废水中的抗糖尿病药物之一。本研究的目的是用 Fe-ZSM-5 (Fe-Z) 沸石作为吸附剂从水溶液中吸附 MET。使用 FTIR、FE-SEM、TEM、XRD 和 N2 吸附-解吸技术分析沸石表征。吸附在间歇系统中进行，并研究了溶液pH值、MET初始浓度、吸附剂剂量、温度和接触时间等参数的影响，以优化吸附过程。吸附等温线由 Langmuir、Freundlich、Temkin 和 Dubinin-Radushkevich 模型研究。具有高相关系数（R2 = 0.999）和最大单层吸附容量（qmax = 14. 992 mg g-1) 在 T = 25 °C 显示与 MET 吸附在 Fe-Z 沸石上的最高一致性。动力学数据最好由伪二级模型表示。此外，还研究了热力学参数，例如焓变 (ΔH)、吉布斯能量变化 (ΔG) 和熵变 (ΔS)。在最佳操作条件下，最高吸附效率为 95.7%：pH = 8.33，t = 25 °C，1.1 g L-1 Fe-Z 和 C0 = 10 mg L-1。所开发的纳米吸附剂具有较高的重复使用率，去除效率仅下降 4.4%。结果表明，Fe-Z 沸石可能是一种很有前途的 MET 去除吸附剂。和熵变（ΔS）进行了研究。在最佳操作条件下，最高吸附效率为 95.7%：pH = 8.33，t = 25 °C，1.1 g L-1 Fe-Z 和 C0 = 10 mg L-1。所开发的纳米吸附剂具有较高的重复使用率，去除效率仅下降 4.4%。结果表明，Fe-Z 沸石可能是一种很有前途的 MET 去除吸附剂。和熵变（ΔS）进行了研究。在最佳操作条件下，最高吸附效率为 95.7%：pH = 8.33，t = 25 °C，1.1 g L-1 Fe-Z 和 C0 = 10 mg L-1。所开发的纳米吸附剂具有较高的重复使用率，去除效率仅下降 4.4%。结果表明，Fe-Z 沸石可能是一种很有前途的 MET 去除吸附剂。