XUE Minmin, QIU Hu, GUO Wanlin. Exceptionally fast water desalination at complete salt rejection by pristine graphyne monolayers. Nanotechnology 2013, 24, 505720.

Exceptionally fast water desalination at complete salt rejection by pristine graphyne monolayers

Minmin Xue, Hu Qiu and Wanlin Guo

Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China
M Xue and H Qiu contributed equally.

Issue 50 (20 December 2013)
Received 5 September 2013, in final form 10 October 2013
Published 27 November 2013

Abstract

Desalination that produces clean freshwater from seawater holds the promise of solving the global water shortage for drinking, agriculture and industry. However, conventional desalination technologies such as reverse osmosis and thermal distillation involve large amounts of energy consumption, and the semipermeable membranes widely used in reverse osmosis face the challenge to provide a high throughput at high salt rejection. Here we find by comprehensive molecular dynamics simulations and first principles modeling that pristine graphyne, one of the graphene-like one-atom-thick carbon allotropes, can achieve 100% rejection of nearly all ions in seawater including Na+, Cl−, Mg2+, K+ and Ca2+, at an exceptionally high water permeability about two orders of magnitude higher than those for commercial state-of-the-art reverse osmosis membranes at a salt rejection of ~98.5%. This complete ion rejection by graphyne, independent of the salt concentration and the operating pressure, is revealed to be originated from the significantly higher energy barriers for ions than for water. This intrinsic specialty of graphyne should provide a new possibility for the efforts to alleviate the global shortage of freshwater and other environmental problems.

link to this article