Chitosan based macromolecular probes for the selective detection and removal of Fe3+ ion.

Chitosan has been widely used due to its biodegradable, cost-effective and environmentally friendly properties. Modification of chitosan attracts much attention as promising methods to detect and remove organic and inorganic pollutants. In this work, chitosan-based macromolecular probes were designed and synthesized. The probes can detect Fe3+ in the presence of other metal ions. The detection mechanism is investigated as well. The probe's fluorescence quenching upon the addition of Fe3+ ion could be ascribed to the complexation between the electron-deficient ion Fe3+ and "C=N" (electron-rich group) of fluorescent chitosan probes. What's more, the obtained fluorescent macromolecular probes can be used for the removal of Fe3+ in solution. The probes could adsorb the Fe3+ in solution and the removal efficiency can reach as high as 62.0% while the removal efficiency of original chitosan is only 16.0%. The probes have good selective detection for Fe3+ and the detection limit reaches 1.2 μM.