TY - JOUR
T1 - Stability of ZIF-8 in water under ambient conditions
AU - Zhang, Huifeng
AU - Zhao, Man
AU - Lin, Jerry
N1 - Funding Information:
The authors would like to acknowledge the financial support from National Key R&D project (No. 2017YFC0403901), National Natural Science Youth Foundation of China (No. 21606059), Marine Public Welfare Industry Research Project (201505006-3) and Special Fund for Basic Scientific Research Business of Central Public Research Institutes (No. K-JBYWF 2016-T10/T11). YSL acknowledges support of National Science Foundation (CBET‐1511005) for the collaboration efforts.
Funding Information:
The authors would like to acknowledge the financial support from National Key R&D project (No. 2017YFC0403901 ), National Natural Science Youth Foundation of China (No. 21606059 ), Marine Public Welfare Industry Research Project ( 201505006-3 ) and Special Fund for Basic Scientific Research Business of Central Public Research Institutes (No. K-JBYWF 2016-T10/T11 ). YSL acknowledges support of National Science Foundation ( CBET‐1511005 ) for the collaboration efforts.
Publisher Copyright:
© 2018
PY - 2019/5/1
Y1 - 2019/5/1
N2 - ZIF-8 shows good stability in a humid atmosphere and has also been studied for applications in aqueous solutions. However, inconsistent results were reported about the stability of ZIF-8 in aqueous solutions. To clarify these inconsistent reports, ZIF-8 water stability tests were conducted using ZIF-8 crystallites of different size prepared by different methods. High crystallinity ZIF-8 crystallites were immersed in pure water at different ZIF-8/water ratio for 24 hours under ambient conditions. The solid powders obtained by evaporation of all the tested ZIF-8/water samples at 40 °C show the presence of a new substance of crystalline structure with a dense, leaf-like morphology. The conversion of ZIF-8 to this substance increases from about 20% to 100% as ZIF-8/water decreases from 6 wt.% to 0.02 wt.%. The solid powder and supernatant were also obtained from the tested ZIF-8/water samples by filtration. Such collected solid powder composes mainly of ZIF-8. The solid powder from the supernatant after evaporation at 40 °C has the same morphology and structure of the new substance discussed above. The results show that ZIF-8 crystallites are not stable in water under ambient conditions. The amount of ZIF-8 crystallites that get dissolved depends on ZIF-8/water ratio and contact time. The solid sample collected by filtration may contain residual ZIF-8, which is responsible for the confusion in the literature about the water stability of ZIF-8. The dissolved zinc and imidazolate ions in aqueous solution, upon condensation by evaporation, form the new substance which is not ZIF-8.
AB - ZIF-8 shows good stability in a humid atmosphere and has also been studied for applications in aqueous solutions. However, inconsistent results were reported about the stability of ZIF-8 in aqueous solutions. To clarify these inconsistent reports, ZIF-8 water stability tests were conducted using ZIF-8 crystallites of different size prepared by different methods. High crystallinity ZIF-8 crystallites were immersed in pure water at different ZIF-8/water ratio for 24 hours under ambient conditions. The solid powders obtained by evaporation of all the tested ZIF-8/water samples at 40 °C show the presence of a new substance of crystalline structure with a dense, leaf-like morphology. The conversion of ZIF-8 to this substance increases from about 20% to 100% as ZIF-8/water decreases from 6 wt.% to 0.02 wt.%. The solid powder and supernatant were also obtained from the tested ZIF-8/water samples by filtration. Such collected solid powder composes mainly of ZIF-8. The solid powder from the supernatant after evaporation at 40 °C has the same morphology and structure of the new substance discussed above. The results show that ZIF-8 crystallites are not stable in water under ambient conditions. The amount of ZIF-8 crystallites that get dissolved depends on ZIF-8/water ratio and contact time. The solid sample collected by filtration may contain residual ZIF-8, which is responsible for the confusion in the literature about the water stability of ZIF-8. The dissolved zinc and imidazolate ions in aqueous solution, upon condensation by evaporation, form the new substance which is not ZIF-8.
KW - Dissolution
KW - Hydrolysis
KW - Metal-organic framework
KW - Water stability
KW - ZIF-8
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U2 - 10.1016/j.micromeso.2018.12.035
DO - 10.1016/j.micromeso.2018.12.035
M3 - Article
AN - SCOPUS:85059058791
SN - 1387-1811
VL - 279
SP - 201
EP - 210
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
ER -