Direct CO2 mineralization using seawater reverse osmosis brine facilitated by hollow fiber membrane contactor

Abstract

The urgent demand for sustainable water management has given rise to widespread seawater desalination, leading to significant brine waste and a substantial carbon footprint resulting from extensive energy consumption. To address this challenge, we propose the utilization of hollow fiber membrane contactors (HFMCs) for direct CO2 mineralization. By mimicking lotus leaf surfaces, HFMs are successfully modified to possess superhydrophobic and antifouling properties, resulting in enhanced operational stability, as evidenced by a marginal 3.5 % flux decline after 10 days. Moreover, HFMCs incorporating these modified membranes achieve remarkable CO2 removal (up to 94 %) and selective mineral carbonation of Ca2+ and Mg2+ through staged pH swing. A techno-economic analysis highlights the superiority of our system compared to traditional amine scrubbing, with a 35 % reduction in CO2 capture costs and the generation of valuable products. This innovative application of HFMCs presents a promising solution for CO2 management, transforming seawater reverse osmosis brine into a valuable resource.