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High-Flux Oil/Water Separation with Interfacial Capillary Effect in Switchable Superwetting Cu(OH)2@ZIF‑8 Nanowire Membranes
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posted on 2018-11-06, 17:49 authored by Qianqian Li, Wenjie Deng, Chuanhao Li, Qingyun Sun, Fangzhi Huang, Yan Zhao, Shikuo LiHighly
ordered architectures with roughness and porous surface
are the key challenges toward developing smart superwetting membranes.
We prepared switchable superwetting Cu(OH)2@ZIF-8 core/shell
nanowire membranes for high-flux oil/water separation as well as simultaneous
heavy-metal ions removal in one step. The well-defined Cu(OH)2@ZIF-8 core/shell nanowire grown on copper mesh with average
length of ca. 15 μm and diameter of ca. 162 nm exhibits high
water contact angle (CA) of ca. 153 ± 0.6°. After modified
by ethanol, the membrane holds the reverse superwettability with oil
(dichloromethane as an example) CA of ca. 155 ± 0.8° underwater.
The separation efficiencies of the membranes are higher than that
of 97.2% with a remarkable flux rate higher than 90 000 L m–2 h–1 for the immiscible oil/water
mixture. And the removal efficiency for Cr3+ ions at 10
ppb can arrive at 99.2 wt % in the toluene-in-water emulsion. The
high performances of the smart superwetting membranes can be attributed
to the interfacial capillary effects of the hierarchical Cu(OH)2@ZIF-8 core/shell nanostructures. This work may provide a
new insight into the design of smart superwetting surfaces for oil/water
separation and target adsorption in one step.