Analyzing the Selectivity of Commercial Cation Exchange Membrane by Electrodeposition of Polyethyleneimine (PEI)
Open Access
- Author:
- Fisher, Matthew
- Area of Honors:
- Chemical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Bruce Logan, Thesis Supervisor
Ali Borhan, Thesis Honors Advisor - Keywords:
- Polyethyleneimine
Trivalent Ions
Rare Earth Elements
Permselectivity
Ion Exchange Membranes
Cations
Potentiostat
Phosphogypsum
Cerium Chloride
Electrodeposition
Wastewater - Abstract:
- The continual growth of technology in today’s world is resulting in an increase in demand for the rare earth elements (REEs) that make up certain microchips. Applications of these microchips range from devices such as mobile phones to ones found in wind turbines. Certain locations within the United States have proven to house enough resources for REEs, however, the reserves of REEs are limited. The objective of this thesis is to study one of the ways REEs can be separated and extracted from mining wastewater found in some of these reserves. One of the current ways of separating ions from water is using processes with ion exchange membranes. The two types of ion exchange membranes are cation exchange membranes (CEM) and anion exchange membranes (AEM). In this study I analyzed the permselectivity of commercial cation exchange membranes for monovalent, divalent, and trivalent ions. Trivalent ions are specifically important since the relevant REEs share the same property. The selectivity analysis was performed for the salts NaCl, CaCl2, MgCl2, and CeCl3. The first analysis was done using pristine CEM to observe the behavior of ions through an uncoated membrane surface. Then, CEM were coated with the polymer polyethyleneimine (PEI) through means of electrodeposition to be used for the next permselectivity analysis runs. The goal of depositing PEI on the membrane surface was to create enough repulsive forces between the coated layer to successfully reject trivalent ions. Permselectivity data for the coated membrane showed lower values for CeCl3 across the membrane, proving that the technique could efficiently reject the trivalent ions and potentially be a viable method for separating REEs from wastewater.