绿色合成纳米铁去除水中铬离子

以桉树叶提取液作为还原剂和稳定剂，绿色合成纳米铁（EL-Fe NPs），用于去除水体中的铬离子。通过SEM、XRD、FT-IR等技术方法对绿色合成的纳米铁去除铬离子反应前后的微观结构进行表征和分析，观察其反应前后的形态结构。主要探究了pH、Cr（VI）溶液初始浓度、EL-Fe NPs投加量和反应温度等因素对EL-Fe NPs去除铬离子效果的影响，研究其吸附动力学并且进行了EL-Fe NPs重复利用实验。实验结果表明：降低溶液初始pH值、升高温度均能提高铬离子的去除率；在铬离子初始浓度10 mg·L-1，EL-Fe NPs投加量1 g·L-1，初始pH=6，反应温度298 K条件下，铬离子的去除率能达到77.2%，其去除过程符合伪一级动力学，反应表观活化能为28.23 kJ·moL-1，表明其为化学控制过程；EL-Fe NPs在重复使用3次之后，铬离子去除率仍能达到35.2%。

Removal of Cr in aqueous solution using green synthesized Fe NPs

Eucalyptus leaf extracts were used as reducing and capping agents to synthesize iron nanoparticles (EL-Fe NPs) by green synthesis methods. The green synthesized iron nanoparticles were used to remove Cr(VI) from aqueous solution. EL-Fe NPs were characterized by SEM, XRD, and FT-IR before and after the reaction. The effects of the experimental conditions, such as pH, the dosage of EL-Fe NPs, the initial concentration of Cr(VI), and the reaction temperature, were investigated. The kinetics of the removal of Cr and the stability of the EL-Fe NPs used in the removal of Cr(VI) were demonstrated. Batch experiments showed that both decreasing the initial concentration of Cr(VI) and increasing the reaction temperature promoted the removal efficiency of Cr. The removal efficiency of Cr reached 77.2% when the initial concentration of Cr(VI) was 10 mg·L-1, the initial pH was 6, the reaction temperature was 298 K, and the dosage of EL-Fe NPs was 1 g·L-1. The removal process conformed to a pseudo first order kinetics model, and the apparent activation energy was 28.23 kJ·mol-1, indicating a chemically controlled reaction. In addition, the removal efficiency of Cr reached 35.2% after three cycles of use.