β-环糊精功能化磁性生物炭除铀(Ⅵ)效果与机理

The adsorption and mechanism of U(VI) removal by β -cyclodextrin-functionalized magnetic biochar

  • 摘要: 为了制备一种吸附效率高、可磁回收的铀吸附材料,本研究制备出β-环糊精修饰磁性生物炭(β-CD@MFBC)复合材料,并系统研究其对U(VI)的吸附性能。通过扫描电子显微镜结合能量色散X射线能谱,Brunauer-Emmett-Teller,振动样品磁强计,傅里叶变换红外光谱和X射线光电子能谱探究β-CD@MFBC对U(VI)的吸附机理。结果显示,β-CD@MFBC具有较高的比表面积和特殊的介孔结构,以及超顺磁性特征。在pH 4.0、303.15 K时,0.28 g·L−1 β-CD@MFBC对10 mg·L−1的U(VI)的最大吸附效率为99.46%,吸附过程符合准二级动力学模型和Freundlich吸附等温线模型,理论吸附量达到219.32 mg·g−1。除U(VI)机理包括β-CD@MFBC中羟基、羧基及Fe/Mn-O基团与U(VI)之间的络合作用。吸附-解吸实验表明β-CD@MFBC具有良好的可重复使用性。这些结果显示了β-CD@MFBC处理U(VI)污染废水的潜力。

     

    Abstract: In order to develop a highly efficient and magnetically recoverable uranium adsorption material, this study prepared β-cyclodextrin-modified magnetic biochar (β-CD@MFBC) composite and systematically investigated its adsorption performance for U(VI). The adsorption mechanism was explored using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller (BET) analysis, vibrating sample magnetometry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Results demonstrated that β-CD@MFBC exhibits a high specific surface area, unique mesoporous structure, and superparamagnetic properties. At pH 4.0 and 303.15 K, the maximum adsorption efficiency of 0.28 g·L−1 β-CD@MFBC to 10 mg·L−1 U (VI) was 99.46%, and the adsorption process was in accordance with the quasi-second-order kinetic model and Freundlich adsorption isotherm model, and the theoretical adsorption capacity reached 219.32 mg·g−1. The U(VI) adsorption mechanism involves coordination between β-CD@MFBC's hydroxyl, carboxyl groups, and Fe/Mn-O complexes. Adsorption-desorption experiments confirmed the material's excellent reusability. These findings highlight the potential of β-CD@MFBC for treating U(VI)-contaminated wastewater.

     

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