Graphene Oxide as a Pb(II) Separation Medium: Has Part of the Story Been Overlooked?

Manh-Thuong Nguyen; Jun Zhang; Venkateshkumar Prabhakaran; Shuai Tan; Eric T Baxter; Vaithiyalingam Shutthanandan; Grant E Johnson; Roger Rousseau; Vassiliki-Alexandra Glezakou

doi:10.1021/jacsau.0c00075

Graphene Oxide as a Pb(II) Separation Medium: Has Part of the Story Been Overlooked?

JACS Au. 2021 Apr 5;1(6):766-776. doi: 10.1021/jacsau.0c00075. eCollection 2021 Jun 28.

Authors

Manh-Thuong Nguyen¹, Jun Zhang¹, Venkateshkumar Prabhakaran¹, Shuai Tan¹, Eric T Baxter¹, Vaithiyalingam Shutthanandan¹, Grant E Johnson¹, Roger Rousseau¹, Vassiliki-Alexandra Glezakou¹

Affiliation

¹ Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.

Abstract

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.