Superfund Research Program
Anode Modification to Target Pb Removal for Drinking Water Purification using Inverted Capacitive Deionization
Project Leader: Lindsay Boehme
Grant Number: R43ES028171
Funding Period: Phase I: July 2017 - February 2019
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PowerTech Water is developing and demonstrating the use of an affordable and widely adoptable solution to remove toxic metals, particularly lead (Pb), from drinking water. To achieve this, PowerTech is using their patented inverted capacitive deionzation (i-CDI) process to create a novel anode that is capable of preferentially removing metal ions from 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 U.S. 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. PowerTech'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 PowerTech's patented i-CDI process that provides stability and pH control during operation.
The major goals of this work are to demonstrate functionalization of carbon-based anodes with soft base ligands to induce specificity for metals adsorption, and to determine the minimum metal concentration, in tap water, allowed to maintain an adsorption selectivity >50 percent over non-metal, divalent ions.