Journal Article

Trace removal of benzene vapour using double-walled metal–dipyrazolate frameworks

Chang, Ze, He, Tao, Zaworotko, Michael J., Bian, Zhen-Xing, Bu, Xian-He, Si, Guang-Rui, Wu, Xue-Qian, Huang, Hongliang, Li, Jian-Rong, Zhang, Yong-Zheng, Xie, Lin-Hua, Nie, Zuo-Ren, Kong, Xiang-Jing

2022

Overview

In principle, porous physisorbents are attractive candidates for the removal of volatile organic compounds such as benzene by virtue of their low energy for the capture and release of this pollutant. Unfortunately, many physisorbents exhibit weak sorbate–sorbent interactions, resulting in poor selectivity and low uptake when volatile organic compounds are present at trace concentrations. Herein, we report that a family of double-walled metal–dipyrazolate frameworks, BUT-53 to BUT-58, exhibit benzene uptakes at 298 K of 2.47–3.28 mmol g −1 at <10 Pa. Breakthrough experiments revealed that BUT-55, a supramolecular isomer of the metal–organic framework Co(BDP) (H 2 BDP = 1,4-di(1 H -pyrazol-4-yl)benzene), captures trace levels of benzene, producing an air stream with benzene content below acceptable limits. Furthermore, BUT-55 can be regenerated with mild heating. Insight into the performance of BUT-55 comes from the crystal structure of the benzene-loaded phase (C 6 H 6 @BUT-55) and density functional theory calculations, which reveal that C–H···X interactions drive the tight binding of benzene. Our results demonstrate that BUT-55 is a recyclable physisorbent that exhibits high affinity and adsorption capacity towards benzene, making it a candidate for environmental remediation of benzene-contaminated gas mixtures. Volatile organic compounds such as benzene are toxic pollutants that cause health issues even at trace concentrations. Here, a double-walled metal–organic framework is presented that demonstrates high uptake at very low pressures (<10 Pa), allowing the removal of benzene to below acceptable indoor limits.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 119/118 / 639/301/357/341 / 639/638/298/921 / Adsorption / Benzene / Benzene - chemistry / Biomaterials / Chemistry and Materials Science / Condensed Matter Physics / Crystal structure / Density functional theory / Environmental cleanup / Gas mixtures / Gases / Hydrocarbons / Materials Science / Metal concentrations / Metal-Organic Frameworks / Nanotechnology / Optical and Electronic Materials / Organic compounds / Pollutants / Selectivity / Sorbents / Trace levels / VOCs / Volatile Organic Compounds