Anode Modification to Target Pb Removal for Drinking Water Purification using Inverted Capacitive Deionization

Powertech Water, Inc., Lexington KY

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Abstract

Project Summary/Abstract PowerTech Water (PTW) intends to demonstrate the use of inverted capacitive deionzation (i-CDI) technology to target the removal of heavy metals, lead (Pb) in particular, from drinking water. Heavy metals such as lead and copper can enter the water distribution system due to corrosion of pipes and fittings, contaminating drinking water. The US Environmental Protection Agency (EPA) established The Lead and Copper Rule in 1991 to limit exposure of these elements and set action levels to 0.015 ppm (15 ppb) and 1.3 ppm for lead and copper, respectively. The water crisis that occurred in Flint, Michigan, last year is an unfortunate case that shows how important it is to ensure lead is below the action level in drinking water. Point-of-use (POU) solutions for lead removal include chemical precipitation, coagulation, ion-exchange, and reverse osmosis (RO), all of which have arduous regeneration steps and/or require costly maintenance to replace materials. PTW's solution offers a low-cost, low-maintenance, reversible adsorption technology that can target metals removal. More specifically, using unique surface chemistries to impart selectivity to the carbon anode, metals can reversibly adsorb and desorb from solution using PTW's patented i-CDI process that provides stability and pH control during operation. The specific aims of this Phase I grant application include: 1. Demonstrating functionalization of carbon-based anodes with soft base ligands to induce specificity for metals adsorption. 2. Determining the minimum metal concentration, in tap water, allowed to maintain an adsorption selectivity >50% over non-metal, divalent ions.