Mario Christofides Bonnie McDevitt Madalyn S. Blondes Ryan J. McAleer Aaron M. Jubb Bu Wang Gaurav Sant Dante Simonetti Steven Bustillos 2024 <div class="abstract-group "><div class="article-section__content en main"><p>An attractive technique for removing CO₂<span>&nbsp;</span>from the environment is sequestration within stable carbonate solids (e. g., calcite). However, continuous addition of alkalinity is required to achieve favorable conditions for carbonate precipitation (pH&gt;8) from aqueous streams containing dissolved CO₂<span>&nbsp;</span>(pH&lt;4.5) and Ca²⁺<span>&nbsp;</span>ions. In this study, a pH-swing process using ion exchange was demonstrated to process 300 L of produced water brine per day for CO₂<span>&nbsp;</span>mineralization. Proton titration capacities were quantified for aqueous streams in equilibrium with gas streams at various concentrations of CO₂<span>&nbsp;</span>(pCO₂=0.03–0.20 atm) and at various flow rates (0.5–2.0 L min⁻¹). Energy intensities for the process were determined to be between 30 and 65 kWh per tonne of CO₂<span>&nbsp;</span>sequestered depending on the composition of the brine stream. A life cycle assessment was performed to analyze the net carbon emissions of the technology which indicated a net CO₂<span>&nbsp;</span>reduction for pCO₂≥0.12 atm (−0.06–−0.39 kg CO₂e per kg precipitated CaCO₃) utilizing calcium-rich brines. The results from this study indicate the ion exchange process can be used as a scalable method to provide alkalinity necessary for the capture and storage of CO₂<span>&nbsp;</span>in Ca-rich waste streams.</p></div></div> application/pdf 10.1002/slct.202400834 en Wiley Ion exchange processes for CO2 mineralization using industrial waste streams: Pilot plant demonstration and life cycle assessment article