Highly selective and high-performance osmotic power generators in subnanochannel membranes enabled by metal-organic frameworks

Yi-Cheng Liu; Li-Hsien Yeh; Min-Jie Zheng; Kevin C-W Wu

doi:10.1126/sciadv.abe9924

Highly selective and high-performance osmotic power generators in subnanochannel membranes enabled by metal-organic frameworks

Sci Adv. 2021 Mar 3;7(10):eabe9924. doi: 10.1126/sciadv.abe9924. Print 2021 Mar.

Authors

Yi-Cheng Liu¹, Li-Hsien Yeh², Min-Jie Zheng³, Kevin C-W Wu⁴

Affiliations

¹ Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
² Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan. lhyeh@mail.ntust.edu.tw kevinwu@ntu.edu.tw.
³ Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
⁴ Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan. lhyeh@mail.ntust.edu.tw kevinwu@ntu.edu.tw.

Abstract

The electric organs of electric eels are able to convert ionic gradients into high-efficiency electricity because their electrocytes contain numerous "subnanoscale" protein ion channels that can achieve highly selective and ultrafast ion transport. Despite increasing awareness of blue energy production through nanochannel membranes, achieving high-performance energy output remains considerably unexplored. Here, we report on a heterogeneous subnanochannel membrane, consisting of a continuous UiO-66-NH₂ metal-organic framework (MOF) and a highly ordered alumina nanochannel membrane. In the positively charged membrane, the angstrom-scale windows function as ionic filters for screening anions with different hydrated sizes. Driven by osmosis, the subnanochannel membrane can produce an exceptionally high Br^-/NO₃ ^- selectivity of ~1240, hence yielding an unprecedented power of up to 26.8 W/m² under a 100-fold KBr gradient. Achieving ultrahigh selective and ultrafast osmotic transport in ion channel-mimetic MOF-based membranes opens previously unexplored avenues toward advanced separation technologies and energy-harvesting devices.

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