Detection of heavy metals by an optical fiber sensor with a sensitive cladding including a new chromogenic calix[4]arene molecule

Fibre optic sensor to detect heavy metal pollutants in water environments

“…The higher absorption observed at pH 6 can be attributed to the availability of the maximum binding sites for the chelation. A similar effect was observed by Benounis and team for the calix(4)arene molecule [17]. The adsorption/binding site formed by S-C-N-N atoms was protonated by H + ions in highly acidic solutions while in the case of pH > 6, the formation of mercury hydroxide occurs which may result in a lower absorption observed in the trend.…”

Transition metal cations extraction by ester and ketone derivatives of chromogenic azocalix[4]arenes

“…These ligands, which are very effective in transferring the transition elements, particularly Ag + , Hg 2+ , Cu 2+ and Cr 3+ donot extract the alkali metal cations to a significant extent [28], in which pphenylazocalix [6]arene is used as ligand. This azocalix [6]arene is a molecule actually used in the heavy metal detection in the literature [29,30].…”

Calixarene complexes with soft metal ions

“…and Cu 2+ ions, for this purpose the optical fiber sensor based on 84 has been built. 122 The detection of the above ions involves the covering of the optical fiber core by a transparent polymer containing a complexing agent; its absorption properties are modified in the presence of the considered ions. The trapping of the ion in the polymeric cladding, i.e.…”