Molecularly soldered covalent organic frameworks for ultrafast precision sieving

Yanqiu Zhang; Jing Guo; Gang Han; Yongping Bai; Qingchun Ge; Jun Ma; Cher Hon Lau; Lu Shao

doi:10.1126/sciadv.abe8706

Molecularly soldered covalent organic frameworks for ultrafast precision sieving

Sci Adv. 2021 Mar 24;7(13):eabe8706. doi: 10.1126/sciadv.abe8706. Print 2021 Mar.

Authors

Yanqiu Zhang^{1

2}, Jing Guo¹, Gang Han³, Yongping Bai¹, Qingchun Ge⁴, Jun Ma², Cher Hon Lau⁵, Lu Shao⁶

Affiliations

¹ MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, State Key Laboratory of Urban Water Resource and Environment, and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China.
² School of Environment, Harbin Institute of Technology, Harbin 150009, China.
³ Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
⁴ College of Environment and Resources, Fuzhou University, No. 2 Xueyuan Road, Fujian 350116, China.
⁵ School of Engineering, The University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JL, UK.
⁶ MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, State Key Laboratory of Urban Water Resource and Environment, and School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China. shaolu@hit.edu.cn.

Abstract

The weak interlamellar interaction of covalent organic framework (COF) nanocrystals inhibit the construction of highly efficient ion/molecular sieving membranes owing to the inferior contaminant selectivity induced by defects in stacked COF membranes and stability issues. Here, a facile in situ molecularly soldered strategy was developed to fabricate defect-free ultrathin COF membranes with precise sieving abilities using the typical chemical environment for COF condensation polymerization and dopamine self-polymerization. The experimental data and density functional theory simulations proved that the reactive oxygen species generated during dopamine polymerization catalyze the nucleophilic reactions of the COF, thus facilitating the counter-diffusion growth of thin COF layers. Notably, dopamine can eliminate the defects in the stacked COF by soldering the COF crystals, fortifying the mechanical properties of the ultrathin COF membranes. The COF membranes exhibited ultrafast precision sieving for molecular separation and ion removal in both aqueous and organic solvents, which surpasses that of state-of-the-art membranes.

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