Cross-linked Graphene Oxide Framework Membranes with Robust Nano-Channels for Enhanced Sieving Ability

• DOI: 10.1021/acs.est.0c05387
• Publication Date: 2020-11-13T15:16:06Z
• Authors: Baoqiu Yuan; Mingxin Wang; Bo Wang; Fenglin Yang; Xie Quan; Chuyang Y. Tang; Yingchao Dong
• Keywords: Nanofiltration

It remains challenging for graphene oxide (GO) membranes to achieve highly efficient performance and sufficient stability aqueous molecule/ion precise separations. Herein, a molecular-level rational structure design protocol was proposed develop ceramic-based framework (GOF) with significantly enhanced sieving removal of salts micropollutants. Via molecular cross-linking strategy, interlayered nanochannels between GO nanosheets can be rationally designed, featuring precisely tailorable channel size, promising surface chemistries remarkably robust suitable separation. Due decreased nanochannel TU (thiourea) molecule improved monovalent salt rejection (95.6% NaCl), outperforming existing state-of-the-art GO-based, commercial organic nanofiltration emerging two-dimensional MoS2 membranes, while moderately decreasing water permeability. In comparison, the GOF cross-linked MPD (m-phenylenediamine) exhibited simultaneous increase in permeability both micropollutants (21.0% 53.3% enhancement chloramphenicol (CAP) solution), breaking their conventional trade-off issue. Cross-linking mechanism indicates that more were formed by stronger covalent bonds via dehydration condensation amine (TU/MPD) carboxyl groups (GO), nucleophilic addition epoxy (GO). Molecule/ion separation involved size (steric hindrance), electrostatic interaction, Donnan effect, partial effect. This work provides novel designing chemistry at subnanometer level construct water-stable functional treatment applications.