Browsing by Author "Hedtke, Tayler"
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Item Synthesis of Graphene Oxide-Polyacrylic Acid Coated Reverse Osmosis Membranes(2019-05) Hedtke, TaylerReverse osmosis (RO) treatment is a practical option for alleviating potable water scarcity. RO is efficient compared to other technologies, and infrastructure is already in place with the opportunity to modify membranes with few complications. One issue plaguing RO is fouling: microbial and mineral, but antifoulants can reduce both types. The respective antifoulants and processes interact, which necessitates further research to understand the processes in relation to each other and to increase RO efficiency. Two syntheses were investigated to attach graphene oxide (GO) to the membrane. Synthesis One used amination with EDC and NHS, and Synthesis Two used polydopamine (PDA). Synthesis One failed to attach GO to the membrane concluded primarily from FTIR spectroscopy. Synthesis Two was successful based on FTIR and Raman spectroscopy and permeability testing. After Synthesis Two's completion, polyacrylic acid (PAA) was attached to GO through UV light-induced polymerization. Permeability results indicated that the PDA-GO-PAA procedure was a promising synthesis.Item Treatment of Per- and Polyfluoroalkyl Substances With S-PAC and Ceramic Membranes(2017-10-12) Hedtke, TaylerPer- and polyfluoroalkyl substances (PFASs) are a contaminant of major concern. The US EPA issued a health advisory limit of 70 ng/L for the two most widely known compounds, PFOS and PFOA, individually or combined. Superfine powdered activated carbon (S-PAC) removes PFASs through adsorption and is followed by membrane filtration to remove the S-PAC particles. S-PAC differs from the traditional treatment train involving granular activated carbon (GAC) in that it has a much smaller particle diameter than GAC. Therefore, S-PAC should remove PFASs more efficiently from water. Ceramic membranes are a promising option for filtering S-PAC from water due to material properties. Both isotherm and microfiltration samples reached over 3 log removal of PFOS, the most concentrated contaminant. This equates to >99.9% removal. This project was completed with contributions from Christopher Bellona from the Department of Civil and Environmental Engineering, Colorado School of Mines.