Superfund Research Program
Novel Filtration Devices for Arsenic Reduction
Project Leader: Orlando Coronell Nieto
Co-Investigators: Cass T. Miller, Mustapha Soukri (RTI International), Gyu Dong Kim (RTI International), Haibo Zhou
Grant Number: P42ES031007
Funding Period: 2020-2025
The Novel Filtration Devices for Arsenic Reduction project has developed new insights into the interfacial polymerization process used to fabricate polyamide water purification membranes. The team discovered that the growth of the polyamide purification layer can be enhanced by modifying monomer supply conditions (i.e., polyamide growth is not self-limited as previously believed). They proposed a new approach to membrane modification and fabrication, which they are currently exploring to produce membranes with improved arsenic removal. Through molecular dynamics studies, they have also shown that a water pressure gradient exists across the purification layer of a reverse osmosis membrane. This finding contradicts the common belief in the membrane science literature that a water pressure gradient does not exist within the membrane. Therefore, the results suggest that pressure-driven advection through the active layer is a water transport mechanism that has been overlooked in the literature. The group has also developed polyethyleneimine (PEI) based granular sorbents for water purification. They functionalized the PEI granular sorbent formulations with iron oxides to enhance their arsenic removal capabilities and evaluated the efficiency of the sorbents to remove inorganic arsenic from simulated brine water in batch tests. All iron-supported sorbents showed a high arsenic removal efficiency (>99 percent). These developments in membrane and granular sorbent technology contribute to the advancement of water purification technologies to remove inorganic arsenic from groundwater.