SPECTROPHOTOMETRIC CHARACTERIZATION OF FUNCTIONALIZED SILVER NANOPARTICLES AS A DEFLUORIDATION SENSOR
Date
2019-05
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Publisher
University of Delaware
Abstract
There is need for sensors that provide specific and selective in operando determination of contaminants worldwide in order to determine efficiency of treatment options and monitor treatment operations once mass scale treatment plants are built.
Fluoride contamination of drinking water is one of the most widespread groundwater pollutants. Identification of fluoride concentration becomes important because at high levels of fluoride exposure can cause dental fluorosis, skeletal fluorosis, thyroid effects, and effects on neuron and brain development. Economical sensors for drinking water are even more important in areas of the world that are industrial and technological infrastructure limited. Though effective, these methods are not economical for practical use in the regions of the world most effected.
A colorimetric sensor using alizarin red S functionalized silver nanoparticles (ARSAgNPs) was developed. This material has been characterized based on spectroscopic and physical studies; it exhibited selective colorimetric detection of Al3+ in aqueous media, and the Al3+ induced aggregated ARSAgNPs exhibited detection of F− with sharp color change and high sensitivity. The mechanistic study revealed that, for Al3+, the color change is due to a shift of the SPR band because of the Al3+ induced aggregation of ARSAgNPs, whereas for F−, the reverse color change with return of the SPR band to its original position is due to dispersion of aggregated ARSAgNPs, as F− removes Al3+ from the aggregated species by complex formation.
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Keywords
Chemical engineering, Silver nanoparticles, Defluoridation sensor