Cu²⁺ sorption from aqueous media by a recyclable Ca²⁺ framework

Abstract

A recyclable Ca-MOF that exchanges Ca2+ by Cu2+ almost quantitatively and quickly was investigated via batch ion-exchange experiments and utilized as a stationary phase in an ion-exchange column for Cu2+ removal from aqueous media.

A Ca2+ MOF combining highly efficient sorption and capability for voltammetric determination of heavy metal ions in aqueous media

“…As also reported in our previous publication, 12 Ca-MOF cannot be regenerated aer the sorption of the various metal ions. However, aer the ion exchange process it is possible to recover the most expensive part of the sorbent, i.e.…”

“…All IR spectra of M-MOFs are missing the characteristic DMA bands and look similar but with noticeable differences. Indeed, none of the IR spectra of M-MOFs matches perfectly with the IR spectrum of Cu-MOF 12 or that of [Ca(H 4 L) (H 2 O) 2 ]$3H 2 O 12 (the latter two spectra are almost identical). Interestingly, the IR spectra of Ni-MOF and Zn-MOF are identical, while the IR spectra of Cd-MOF and Pb-MOF are similar but not identical to each other and they differ from that of Ni-MOF and Zn-MOF.…”

“…Similarly, recycling of the ligand can be performed for Pb-MOF in the ion-exchange column, as reported in our previous publication. 12 Results and discussion M 2+ exchange studies of Ca-MOF Our previous studies indicated that Ca-MOF is a very efficient sorbent for Cu 2+ , 12 whereas this MOF shows very slow exchange for lanthanide ions. 16 In the present study, we investigated the exchange properties of Ca-MOF for other divalent metal ions such as Ni 2+ , Zn 2+ , Cd 2+ and Pb 2+ .…”

“…There is no dissociation of the MOF in water as revealed by 1 H NMR experiments in which the Ca-MOF solid was placed in D 2 O. 12 The 1 H NMR data showed that no ligand is leached from the MOF. 12 Even in the presence of metal ions (such as Zn 2+ ) in water solution, we could not observe any leaching of the ligand in water.…”

“…S6 †), thus fullling an important criterion for a sorbent to be used as a stationary phase in ion exchange columns. 12 The nal step in our investigations was the study of the column Pb 2+ sorption properties of the Ca-MOF material. We chose Pb 2+ among the other heavy metal ions for these studies because of the highly efficient Pb 2+ sorption properties of Ca-MOF and the urgent need to nd suitable sorbents to address the pollution of water resources by Pb 2+ representing one of the most important environmental issues.…”