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华中农业大学胡红青教授团队使用壳聚糖饱和加载到蒙脱石表面,通过X射线衍射和傅立叶变换红外光谱仪对合成物进行表征并确认其插层和复合状态,然后分析了Pb(II)、Cu(II) 和Cd(II) 的吸附动力学、热力学和等温吸附的表观吸附量、多模型拟合。相关成果发表于Applied Clay Science(IF=4.605)。
论文第一作者为湖北工程学院胡超博士,通讯作者为华中农业大学胡红青教授,祝鹏飞、蔡敏、付庆灵参与了试验研究。
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•The composite had adsorption affinity sequence of Pb2 + > Cu2 + > Cd2 +.
•One would enhance another metal adsorption in Pb—Cu and Cu—Cd.
•Adsorptions were both heterogeneous and exothermic reaction.
The montmorillonite-chitosan composite could provide hydrophobicity and functional groups to enhance the performances of montmorillonite in wastewater treatment. The composites showed good abilities to remove the pollutants, such as heavy metals and dyes. However, the comparative adsorption of multiple metals on the fixed C-content nanocomposite needs to be studied further. This paper presents the adsorption of Pb2 +, Cu2 +, and Cd2 + by the nanocomposite of chitosan saturated montmorillonte. The composite was synthetized and characterized by X-ray diffraction and Fourier transform infrared spectrometer. The kinetics (single and binary systems), thermodynamics and isotherm adsorption studies of the three cations on the nanocomposite were conducted, and the data were fitted with models. Results showed, the affinity sequence of the adsorption toward the 3 cations is Pb2 + > Cu2 + > Cd2 +. Under most experimental conditions, one of the cations could enhance the adsorption of the other present in the binary system. The adsorption of the 3 cations could be best fitted with pseudo-second order equation. The metal adsorption is a heterogeneous and exothermic reaction on the surface of the composite, and Pb2 +, Cu2 + adsorption are spontaneous reaction at 25–50 °C.
蒙脱石-壳聚糖复合物被认为是性能良好、绿色天然的吸附剂。与纯壳聚糖相比,蒙脱石-壳聚糖复合物具备更好的机械性能,并能够保持壳聚糖的反应活性。因有机-无机体系表面的复杂性,重金属在蒙脱石-壳聚糖复合物上的吸附特性及选择性存在一些矛盾和争议。为实现该复合物对重金属污染物去除的应用,多种金属共存条件下的比较和竞争性吸附需要进一步的研究。
该研究使用壳聚糖饱和加载到蒙脱石表面,通过X射线衍射和傅立叶变换红外光谱仪对合成物进行表征并确认其插层和复合状态。为实现较全面的吸附比较并探究复合物的表面特性,该文分析了Pb(II)、Cu(II) 和Cd(II) 的吸附动力学、热力学和等温吸附的表观吸附量、多模型拟合。实现了不同浓度条件下,三种重金属阳离子(单一和二元重金属体系)吸附动力学较全面的比较和分析。
结果表明,在不同初始浓度的Pb-Cu和Cu-Cd的二元重金属体系中,表观吸附量、qe(理论吸附量)和k2(吸附系数)变化反映出某一阳离子可以增强另一类阳离子的吸附;不同初始浓度条件下3种阳离子的吸附亲和力顺序表现为Pb2+> Cu2+> Cd2+,与其电负性大小正相关;重金属阳离子在复合物表面的吸附属于异质放热反应,Pb,Cu的吸附在25-50℃条件下属于自发反应。
该结果可提供蒙脱石-壳聚糖复合物对重金属二价阳离子的吸附特性。根据重金属的吸附特性,蒙脱石饱和加载壳聚糖后的表面特性变化可供土壤矿物-有机物-重金属作用体系的研究参考。
论文引用格式:
Hu C, Zhu P F, Cai M, et al. Comparative adsorption of Pb(II), Cu(II) and Cd(II) on chitosan saturated montmorillonite: Kinetic, thermodynamic and equilibrium studies[J]. Applied Clay Science, 2017, 143, 320-326.
DOI:
10.1016/j.clay.2017.04.005
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