Membrane Distillation–Crystallization for Sustainable Carbon Utilization and Storage

Abstract

Anthropogenic greenhouse gas emissions from power plants can be limited using postcombustion carbon dioxide capture by amine-based solvents. However, sustainable strategies for the simultaneous utilization and storage of carbon dioxide are limited. In this study, membrane distillation−crystallization is used to facilitate the controllable production of carbonate minerals directly from carbon dioxide-loaded amine solutions and waste materials such as fly ash residues and waste brines from desalination. To identify the most suitable conditions for carbon mineralization, we vary the membrane type, operating conditions, and system configuration. Feed solutions with 30 wt % monoethanolamine are loaded with 5−15% CO 2 and heated to 40−50 °C before being dosed with 0.18 M Ca 2+ and Mg 2+ . Membranes with lower surface energy and greater roughness are found to more rapidly promote mineralization due to up to 20% greater vapor flux. Lower operating temperature improves membrane wetting tolerance by 96.2% but simultaneously reduces crystal growth rate by 48.3%. Sweeping gas membrane distillation demonstrates a 71.6% reduction in the mineralization rate and a marginal improvement (37.5%) on membrane wetting tolerance. Mineral identity and growth characteristics are presented, and the analysis is extended to explore the potential improvements for carbon mineralization as well as the feasibility of future implementation.

Environmentally Friendly Photothermal Membranes for Halite Recovery from Reverse Osmosis Brine via Solar-Driven Membrane Crystallization

“…Likewise, the population density of crystals on GO10 (1862.02 crystals•cm −2 ) was 3-fold higher than that on the bare PVDF and about +20% higher with respect to the observations on the GO2.5 and CB2.5 membranes. This agrees with classical nucleation theory [38,64]: the boosted vaporization of water on GO10 facilitated nucleation, with the consequent formation of a large number of small nuclei. Furthermore, the shorter nucleation time guaranteed to the nuclei a longer resilience time in a supersaturated solution, promoting their growth.…”