Adsorption of arsenic on iron modified attapulgite (Fe/ATP): surface complexation model and DFT studies
Adsorption of arsenic on iron modified attapulgite (Fe/ATP): surface complexation model and DFT studies
复制标题
铁改性凹凸棒石 (Fe/ATP) 上砷的吸附：表面络合模型和 DFT 研究
DOI：
10.1007/s10450-018-9959-9
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发表时间：
2018-07-01
影响因子：
3.3
通讯作者：
Wang, Linling
中科院分区：
文献类型：
--
作者：
Pan, Hong;Hou, Huijie;Wang, Linling
研究了铁改性凹凸棒石(Fe/ATP)对As(V)的吸附行为。采用超声共沉淀法制备了Fe(III)/ATP和Fe(II，III)/ATP两种Fe/ATP纳米粒子，并用扫描电子显微镜、X射线衍射仪、X射线光电子能谱、红外光谱和Zeta电位分析对其进行了表征。As(V)在Fe/ATP上的吸附等温线符合Freundlich模型。吸附动力学符合准二级动力学模型，Fe(III)/ATP的准二级速率常数(k，min(-1))为-0.033，Fe(II，III)/ATP为-0.037。铁/三磷酸腺苷的吸附容量是三磷酸腺苷的5-6倍(5.2mgg(aEU‘1))。FT-IR和XPS分析表明，Fe/ATP上的Fe-O(H)基团对As(V)具有较强的相互作用。Fe(III)/ATP比Fe(II，III)/ATP具有更高的吸附容量，这是由于Fe(III)/ATP表面羟基较多所致。表面络合模型和密度泛函理论计算表明，As(V)在Fe/ATP表面的吸附是通过形成单齿络合物实现的。
The adsorption behaviors of arsenic As(V) on the iron modified attapulgite (Fe/ATP) were studied. Two types of Fe/ATP nanoparticles, including Fe(III)/ATP and Fe(II,III)/ATP were prepared by ultrasonic co-precipitation method and characterized using SEM, XRD, XPS, FT-IR and zeta potential analyses. The adsorption isotherms of As(V) on Fe/ATP were well fitted by Freundlich model. The adsorption kinetics data were followed by the pseudo-second-order model with the pseud-second-order rate constant (k, min(-1)) of - 0.033 for Fe(III)/ATP and - 0.037 for Fe(II,III)/ATP, respectively. Adsorption capacities of Fe/ATP were 5-6 times higher than ATP (5.2 mg g(aEuro'1)). The Fe-O(H) groups on Fe/ATP contributed to the strong interaction for As(V), confirmed with FT-IR and XPS analyses. The higher adsorption capacity of Fe(III)/ATP than that of Fe(II,III)/ATP was attributed to more surface hydroxyl groups on Fe(III)/ATP. Surface complexation models and density functional theory calculations demonstrated that As(V) sorption on Fe/ATP was by virtue of the formation of monodentate complexes.