Coagulation Behavior of Graphene Oxide on Nanocrystallined Mg/Al Layered Double Hydroxides: Batch Experimental and Theoretical Calculation Study

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• 作者：Yidong Zou ; Xiangxue Wang ; Yuejie Ai ; Yunhai Liu ; Jiaxing Li ; Yongfei Ji ; Xiangke Wang
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：April 5, 2016
• 年：2016
• 卷：50
• 期：7
• 页码：3658-3667
• 全文大小：613K
• ISSN：1520-5851

文摘

Graphene oxide (GO) has attracted considerable attention because of its remarkable enhanced adsorption and multifunctional properties. However, the toxic properties of GO nanosheets released into the environment could lead to the instability of biological system. In aqueous phase, GO may interact with fine mineral particles, such as chloridion intercalated nanocrystallined Mg/Al layered double hydroxides (LDH–Cl) and nanocrystallined Mg/Al LDHs (LDH–CO₃), which are considered as coagulant molecules for the coagulation and removal of GO from aqueous solutions. Herein the coagulation of GO on LDHs were studied as a function of solution pH, ionic strength, contact time, temperature and coagulant concentration. The presence of LDH–Cl and LDH–CO₃ improved the coagulation of GO in solution efficiently, which was mainly attributed to the surface oxygen-containing functional groups of LDH–Cl and LDH–CO₃ occupying the binding sites of GO. The coagulation of GO by LDH–Cl and LDH–CO₃ was strongly dependent on pH and ionic strength. Results of theoretical DFT calculations indicated that the coagulation of GO on LDHs was energetically favored by electrostatic interactions and hydrogen bonds, which was further evidenced by FTIR and XPS analysis. By integrating the experimental results, it was clear that LDH–Cl could be potentially used as a cost-effective coagulant for the elimination of GO from aqueous solutions, which could efficiently decrease the potential toxicity of GO in the natural environment.