Magneto-Fluorescent Hybrid Sensor CaCO(3)-Fe(3)O(4)-AgInS(2)/ZnS for the Detection of Heavy Metal Ions in Aqueous Media

Heavy metal ions are not subject to biodegradation and could cause the environmental pollution of natural resources and water. Many of the heavy metals are highly toxic and dangerous to human health, even at a minimum amount. This work considered an optical method for detecting heavy metal ions using colloidal luminescent semiconductor quantum dots (QDs). Over the past decade, QDs have been used in the development of sensitive fluorescence sensors for ions of heavy metal. In this work, we combined the fluorescent properties of AgInS(2)/ZnS ternary QDs and the magnetism of superparamagnetic Fe(3)O(4) nanoparticles embedded in a matrix of porous calcium carbonate microspheres for the detection of toxic ions of heavy metal: Co(2+), Ni(2+), and Pb(2+). We demonstrate a relationship between the level of quenching of the photoluminescence of sensors under exposure to the heavy metal ions and the concentration of these ions, allowing their detection in aqueous solutions at concentrations of Co(2+), Ni(2+), and Pb(2+) as low as ≈0.01 ppm, ≈0.1 ppm, and ≈0.01 ppm, respectively. It also has importance for application of the ability to concentrate and extract the sensor with analytes from the solution using a magnetic field.