Exploration of adsorption mechanism of 2-phosphonobutane-1,2,4-tricarboxylic acid onto kaolinite and montmorillonite via batch experiment and theoretical studies
Exploration of adsorption mechanism of 2-phosphonobutane-1,2,4-tricarboxylic acid onto kaolinite and montmorillonite via batch experiment and theoretical studies
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通过批量实验和理论研究探索2-膦酰丁烷-1,2,4-三羧酸在高岭石和蒙脱土上的吸附机理
DOI：
10.1016/j.jhazmat.2020.123810
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发表时间：
2020
影响因子：
13.6
通讯作者：
Mingzhu Xia
中科院分区：
文献类型：
--
作者：
Sidi Zhu;Muhammad Asim Khan;Fengyun Wang;Zahira Bano;Mingzhu Xia
选择两种不同晶体结构的粘土矿物高岭石（Kaol）和蒙脱石（Mt），通过批控制实验和理论研究，研究了它们对2-膦酰基丁烷-1，2，4-三羧酸（PBTC）的比较吸附。吸附等温线符合Langmuir吸附模型，吸附动力学符合准二级动力学模型，分别证实了吸附过程为单分子层吸附和化学吸附。在pH=3.0、T=298 K时，高岭土和蒙脱石对PBTC的最大去除量分别为72.297 mg/g和121.163 mg/g。同时，采用分子动力学（MD）模拟和密度泛函理论（DFT）对吸附机理进行了研究.首次将界面力场引入Materials Studio软件，探讨粘土矿物界面的微观机理。动力学行为验证了羧基上的氧原子在Mt外表面有较强的亲合力，与实验数据吻合较好。在密度泛函理论计算中，采用分子货车德瓦耳斯（vdW）表面的定量分析来预测亲电反应的反应位点。独立梯度模型（IGM）和Hirshfeld表面分析表明，高吸附效果主要归因于氢键作用。这些发现提高了我们探索不同粘土矿物界面处相关性质的能力。
Two clay minerals, kaolinite (Kaol) and montmorillonite (Mt) with different crystal structures were chosen to investigate the comparative adsorption of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) through batch control experiments and theoretical studies. The systematical isotherm and kinetic studies agreed with Langmuir model and pseudo-second-order model, confirming a monolayer and chemisorption interaction process, respectively. The maximum removal capacities of Kaol and Mt for PBTC were 72.297 mg/g and 121.163 mg/g at pH=3.0 and T=298 K, respectively. Furthermore, the adsorption mechanisms were investigated by molecular dynamic (MD) simulations and density functional theory (DFT). The Interface force field (IFF) was firstly introduced into Materials Studio package to explore the microscopic mechanism of clay mineral interface. The dynamics behaviors verified that the oxygen (O) atom of carboxyl group has stronger affinity at the external surface of Mt, which consistent with the experimental data well. For DFT calculations, quantitative analysis around molecular van der Waals (vdW) surface was adopted to predict reactive sites for the electrophilic reaction. Independent Gradient Model (IGM) and Hirshfeld surface analyses in Multiwfn indicated that the high adsorption effect mainly attributes to hydrogen bond action. These findings improve our ability to explore the related properties occurring at the interface of different clay minerals.