Abstract:
A new Ca2+ two-dimensional framework, namely [Ca(H4L)(DMA)(2)]center
dot 2DMA (Ca-MOF) was obtained from the initial use of
N,N’-bis(2,4-dicarboxyphenyl)-oxalamide (H6L). We discovered that this
Ca-MOF is capable of exchanging the Ca2+ ions by Cu2+ almost
quantitatively in a matter of seconds in aqueous solution. The highly
efficient Cu2+ sorption properties exhibited by the Ca-MOF were
investigated in detail via batch ion-exchange studies. In addition, the
Ca-MOF was utilized as a stationary phase in an ion-exchange column for
Cu2+ removal from aqueous media. Furthermore, we were able to recycle
the most expensive part of the framework, i.e. the H6L, by treating the
column with dilute NaOH followed by HCl. The Ca-MOF represents the first
example of any MOF capable of exchanging its constituent metal ions that
is shown to be a highly effective ion-exchange material, thus opening a
new window in the exploitation of MOFs for ion-exchange applications.
