Location: Presented via Zoom: 828.685.7838; Shown in EER 3.646
Sponsor: Department of Energy (DOE) Energy Frontier Research Center (EFRC) Materials for Water and Energy Systems (M-WET)
Title: Membrane Processes for Separation of Critical Ions
Abstract
This presentation will describe nanofiltration (NF), diafiltration, and ultrafiltration with polymeric ligands to isolate critical materials. NF selectively concentrates multivalent ions such as La3+, and selective rejection of these ions creates an electric field that leads to negative rejection of monovalent ions. Negative rejection enables rapid removal of monovalent ions, including protons, during diafiltration. Separations of similar multivalent ions will likely require selective ligands and isolation of free metal ions from metal-ligand complexes. Solvent extraction separates metal ions and their complexes using hydrophobic ligands, but the technique contaminates large volumes of water.
Our group employs ultrafiltration membranes to separate polymeric metal-ion complexes from free ions, and negative rejection enhances these separations. Using different pH values, polyethyleneimine can facilitate Cu2+/ Ni2+, Ni2+/Mn2+, Co2+/Mn2+, and Co2+/Li+ separations relevant to battery recycling. Free metal-ion concentrations decrease exponentially with diafiltration volume to give metal-ion purities as high as 99.99%. Current research is examining whether covalent organic frameworks can separate metal ions from their complexes with smaller ligands.
Bio
Merlin Bruening received BS and MS degrees in Chemical Engineering and Chemistry from Brigham Young University and a PhD from the Weizmann Institute of Science. After a postdoctoral position at Texas A&M University, he was a professor of chemistry at Michigan State University for 19 years, and he joined Notre Dame 10 years ago as a professor of Chemical and Biomolecular Engineering. He is currently the Donald and Susan Rice Professor of Engineering. Merlin developed protein purification membranes that constitute the Capturem product line at Takara Bio, and he has created membranes with high selectivities in ion separations.