β-环糊精改性磁性棕榈纤维生物炭高效去除水中Pb(II)

β-cyclodextrin modified magnetic palm fiber biochar for highly efficient Pb(II) removal from water

  • 摘要: 为解决水体中重金属Pb(II)污染,本文以棕榈纤维为原材料,通过化学共沉淀法制备得到β-环糊精磁性棕榈纤维生物炭(β-CD@PFMBC)用于高效去除水溶液中的Pb(II)。通过FTIR、XRD、BET、SEM、Raman和VSM等手段对材料的结构和形貌进行了表征。通过单因素实验对Pb(II)的吸附性能进行了分析,探究了吸附剂对Pb(II)的吸附机制及回收利用性。结果表明:β-CD@PFMBC相比原始生物炭比表面积增加,表面官能团数量增多。拟二级动力学模型和Langmuir吸附等温线模型均能很好地描述对Pb(II)的吸附过程,表明吸附过程为化学吸附和单层吸附。由Langmuir吸附等温线模型拟合得知,β-CD@PFMBC在303 K时最大理论吸附量为625.49 mg∙g−1,明显高于原始生物炭。热力学研究表明吸附反应是自发吸热过程。β-CD@PFMBC表面的含氧基团与Pb(II)产生了表面络合和静电相互作用。5次循环解吸后,对Pb(II)去除率仍能达到79%以上。以上结果表明β-CD@PFMBC对水溶液中Pb(II)的去除具有一定的应用潜力。

     

    Abstract: In order to solve the water contamination arises from heavy metal Pb(II), β-cyclodextrin modified magnetic palm fiber biochar (β-CD@PFMBC) was prepared with palm fiber as raw material by chemical coprecipitation method for efficient removal of Pb(II) from aqueous solution. The structure and morphology of the material were characterized by FTIR, XRD, BET, SEM, Raman and VSM. The adsorption properties of Pb(II) were analyzed through single factor experiment. The adsorption mechanism and recycling of Pb(II) were also explored. The results show that the specific surface area and the number of surface functional groups of β-CD@PFMBC increased compared with the pristine biochar. The adsorption process of Pb(II) can be better described by both the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model, which indicates that the adsorption process is chemical adsorption and monolayer adsorption. According to the Langmuir isotherm model, the maximum theoretical adsorption capacity of β-CD@PFMBC at 303 K is 625.49 mg∙g–1, which is significantly higher than that of the pristine biochar. Thermodynamic studies show that the adsorption is a spontaneous endothermic process. The oxygen-containing groups on the surface of β-CD@PFMBC produce surface complexation and electrostatic interaction with Pb(II). The removal ration remains above 79% after five cycles of adsorption-desorption. It can be expected that β-CD@PFMBC will be of potential application in removing of Pb(II) from aqueous solution.

     

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