Energy-Efficient Ethanol Concentration Method for Scalable CO2 Electrolysis

Electrosynthesis of ethanol fromcarbon dioxide (CO2) is a promising route to generate asustainable fuel anda convenientfeedstock for chemical manufacturing. While significant progresshas been achieved in boosting the selectivity of CO2 toethanol, the subsequent ethanol separation remains a bottleneck, whichprevents leveraging the laboratory results into large-scale systems.Here we report vacuum membrane distillation as a method that efficientlyconcentrates dilute ethanol streams produced by CO2 electrolysis(CO2R), yielding up to & SIM;40 wt% ethanol in pure water.In our design considerations, we include previously underappreciatedthermodynamic properties of the catholyte (salting-out effect) andpropose strategies allowing a more precise estimation of energy inputsto the separation processes. Our work provides the basis for the detaileddesign of complex systems which integrate flow reactors and liquidseparations and supports scaling of the systems previously considerednot optimized for industrial use.

Automated summary

Electrosynthesis of ethanol from carbon dioxide (CO2) is a promising route for sustainable fuel and chemical manufacturing. However, the bottleneck of ethanol separation has hindered the scaling of this process. This study presents vacuum membrane distillation as an efficient method to concentrate dilute ethanol streams produced by CO2 electrolysis (CO2R), achieving high ethanol concentrations in pure water. The work also considers thermodynamic properties and proposes strategies for precise estimation of energy inputs to separation processes, supporting the optimization of complex systems for industrial use.