Nguyen Manh-Thuong, Zhang Jun, Prabhakaran Venkateshkumar, Tan Shuai, Baxter Eric T, Shutthanandan Vaithiyalingam, Johnson Grant E, Rousseau Roger, Glezakou Vassiliki-Alexandra
Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
JACS Au. 2021 Apr 5;1(6):766-776. doi: 10.1021/jacsau.0c00075. eCollection 2021 Jun 28.
A key problem associated with the design of graphene oxide (GO) materials and their tuning for nanoscale separations is how specific functional groups influence the competitive adsorption of solvated ions and water at liquid/graphene interfaces. Computation accompanied by experiment shows that OH and COOH exert an influence on water adsorption properties stronger than that of O and H functional groups. The COO anions, following COOH deprotonation, stabilize Pb(II) through strong electrostatic interactions. This suggests that, among the functional groups under study, COOH offers the best Pb(II) adsorption capacity and the ability to regenerate the sorbent through a pH swing. In line with computation, striking experimental observations revealed that a substantial increase in Pb(II) adsorption occurs with increasing pH. Our findings provide a systematic framework for controlled design and implementation of regenerable C-based sorbents used in separations and desalination.
与氧化石墨烯（GO）材料的设计及其用于纳米级分离的调谐相关的一个关键问题是特定官能团如何影响溶剂化离子和水在液/石墨烯界面处的竞争吸附。计算结合实验表明，OH和COOH对水吸附性能的影响强于O和H官能团。COOH去质子化后产生的COO阴离子通过强静电相互作用稳定Pb（II）。这表明，在所研究的官能团中，COOH具有最佳的Pb（II）吸附能力以及通过pH变化使吸附剂再生的能力。与计算结果一致，引人注目的实验观察结果表明，随着pH值的升高，Pb（II）的吸附量大幅增加。我们的研究结果为用于分离和脱盐的可再生碳基吸附剂的可控设计和应用提供了一个系统框架。
