Industrial growth in the areas surrounding Las Cucharillas Marsh in Puerto Rico has led to significant contamination of neighboring soils and water bodies with highly toxic heavy metals such as mercury, arsenic, and lead. The high concentration of these heavy metals found in the Pterocarpus, and Mangrove Zone shows the current soil quality in this ecosystem and the health impact on the nearby community. In developing an efficient system for treating these heavy metal contaminated ecosystems, nano Zero Valent Iron (nZVI) particles are a promising alternative for reducing these pollutants. The nZVI has been widely used for groundwater and soil remediation to improve contaminant removal and production costs. This research aims to develop a remediation system with nZVI for the health treatment of heavy metal poisoning. The target contaminant we are currently working with is lead. The nZVI particles are synthesized by preparing a 0.6 M solution of iron chloride in a nitrogen environment and titrated with a 0.8 M solution of the reducing agent sodium borohydride which precipitates the metal iron, then stored in a desiccator under nitrogen and vacuum. The samples were analyzed by different spectroscopic techniques such as Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The analysis of the soil sampled at Las Cucharillas Marsh shows high lead concentrations. Scanning Electron Microscopy with X-ray Fluorescence-Energy Dispersive Spectroscopy (SEM-EDS) results show how the filament morphology and composition of nZVI particles are affected when removing lead. Using ICP-OES and pH curves, it is shown that the nZVI removed all the lead from the solution in less than one hour of treatment. In the X-ray Diffraction (XRD) characterization, the presence of lead on the surface of the nZVI was determined at different treatment times with a standard solution of the metal. Cyclic voltammetry characterizations were also performed by modifying a glassy carbon electrode to know the potential window and the electrochemical behavior of the nZVI to modify the electrode with a nZVI-lead ink in the future as an alternative for the removal of the heavy metal. These results demonstrate the suitability of nZVI for the removal of lead from water bodies and serve as an inspiration to remove other heavy metals with nZVI by electrochemistry and use them in solar cells, besides considering nZVI as a remediation system for the removal of lead from the human body.

Heavy metals environmental health remediation with nano zero valent iron (nZVI) particles

ACS Spring 2022

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