Polyelectrolyte assemblies for the detection of lead in water

MENDEZ DE LEO, LUCILA PAULA; CELESTE MAGALLANES; GONZÁLEZ, GRACIELA A.

Congreso; #EnvChem2021: Chemistry of the Whole Environment Research (online); 2021

It is well known that the quality of water bodies all over the world is threatened by contamination with several components. Industrial activity releases a wide range of waste products into the environment, including heavy metals.1 Of particular concern, lead (II) have been associated with health problems such as cancer, skin lesions, cardiovascular disease, and neurological disorders.2 Its persistence and bioaccumulation, makes it essential to develop functionalized interfaces and methods for its monitoring and retention in natural and industrial matrices. Monitoring industrial processes, such as battery recovery, is the route for effluent re-entry into the production process towards a greener industry. Among all the commonly used techniques for heavy metal detection, electrochemical methods have advantages because they are inexpensive, highly sensitive, easy to use, portable, and applicable for field monitoring of environmental samples.3This work used electrochemical impedance spectroscopy (EIS) for final characterization of the system after the interaction of Pb (II) in an aqueous matrix with polyelectrolyte assemblies constructed by drop casting technique on screen-printed electrodes. Polyallylamine (PAH) and polystyrenesulfonate (PSS) were used as conductive polymers to functionalize the surface with functional groups that would act as chelating of Pb(II). The influence on cation adsorption and the electrochemical signal obtained by metal ion reduction was evaluated. Infrared characterization by attenuated total reflection (ATR) was carried out to evaluate the modification of the surface, its stability against treatment and the changes induced by the adsorption of lead cation.After testing several construction conditions, it was found that by performing three successive deposition of polyelectrolytes in a 1:1 ratio and with 30-minute incubation. A marked trend was achieved in the intensity of the reduction signal in the range of lead concentration 0.5 - 2.5 mM. In addition, using the EIS technique, a linear correlation was found between the resistance of the charge transfer of the film and the inverse of the concentration, as seen in figure 1.1. Sens. Actuators B Chem. 2018, 255, 2657.2. Environ. Int. 2018, 120, 404.3. Anal. Methods 2020, 12, 1547.