Composite membranes based on self-crosslinking polyelectrolyte-wrapped ZIF-8/CNT nanoparticles for solar steam evaporation

• Published in: Materials advances Vol. 4; no. 7; pp. 1628 - 1636
• Main Authors: Zhu, Yingying, Lan, Hongyu, He, Panpan, Zhu, Xiangwei, Gong, Jiang, Dong, Zhiyue, Zeng, Minghua
• Format: Journal Article
• Language: English
• Published: 03.04.2023
• ISSN: 2633-5409; 2633-5409
• DOI: 10.1039/d3ma00075c

Zeolitic imidazolate frameworks (ZIFs) are widely studied for selective transport of small molecules with their designable channels and cage-like pores. Herein, we design solar-thermal hybrid membrane ZCP-20 (ZIF-8/CNTs@PCMVIMBr-20), where ZIF-8 is used as a water transmission channel. ZIF-8 was integrated with self-crosslinking PCMVIMBr (poly[1-cyanomethyl-3-vinylimidazolium bromide]), where its imidazole moiety coordinates with Zn ions to give a mechanically robust membrane. The hydrophobic channels of ZIF-8 enable the formation of discrete water clusters. Differential scanning calorimetry and dark water evaporation rate evaluation indicate that the water evaporation enthalpy in the ZCP-20 membrane is 1.00 kJ g −1 . Consequently, the ZCP-20 membrane exhibits a high evaporation rate of 2.48 kg m −2 h −1 under one sun irradiation and displays stable evaporation rates for 20 h. Remarkably, the ZCP-20 membrane can tolerate various water sources ( e.g. , dye-polluted water) or even strongly acidic (pH = 1) or basic (pH = 13) solutions. The suitably hydrophobic feature of ZIF-8 channels was used as water transmission path in ZCP-x membranes to reduce the water evaporation enthalpy. These membranes show high evaporation rate and efficiency for solar-thermal desalination performance.