Since the introduction of industry, the amount of naturally occurring safe drinking water has drastically decreased because of an increase in toxic heavy metals such as lead, arsenic, and cadmium from industrial waste. Currently, there are approximately 500,000 children ages 1-5 years in America diagnosed with blood lead levels above those recommended by the Centers for Disease Control and prevention (CDC). Chronic lead poisoning can lead to malfunctioning organs, damaged tissues, encephalopathy, anemia, nervous disorders, and even death. The objective of this project is to develop a lead removal technique that is environmentally friendly, effective, and cost-efficient. Here, we describe the construction of a novel apparatus that utilizes coordination chemistry to extract lead from a bulk water supply. In addition, we present preliminary results on its efficacy. The apparatus consists of a simple PVC pipe capped with a semi-permeable, organic membrane separating the source phase, containing lead ions, from the lead-trapping reservoir inside the PVC pipe, which contains the metal chelator, ethylenediaminetetraacetic acid (EDTA). Lead is drawn into the device through the membrane via an ionophore (dicyclohexano-18-crown-6) that allows the lead ions to be passed though the hydrophobic membrane into the trapping reservoir, where it forms a stable complex with EDTA. Data presented here demonstrate that the apparatus can be used to remove lead from a contaminated water source to concentrations below 15 ppb, which is the “action level” set by the Environmental Protection Agency (EPA). The reusable device consistently reduces lead concentrations below 15 ppb with the most common final lead concentrations remaining between 6 ppm and 8 ppm. Additional experiments show that the device can be reused without changing the membrane or lead trapping solution within the reservoir. Reusing the device showed a gradual decrease in efficiency that corresponds to a decrease in free EDTA available for metal chelation in the trapping solution.

Novel method for the extraction of lead ions from bulk water supplies using chelation chemistry

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.