Life cycle assessment of photo-electrodialysis for freshwater production: A Qatar-based study

This study evaluates the environmental sustainability of brackish water desalination using photo-electrodialysis (photo-ED). A cradle-to-gate life cycle assessment (LCA) was conducted for a small-scale theoretical photo-ED desalination plant in Qatar. The system employs a Pt/Ir-coated titanium photo-anode that harnesses sunlight to drive ion transport. The assessment covers brackish water extraction, pre-treatment, photo-ED cell operation, and post-treatment. Life cycle impact assessment (LCIA) results indicate a global warming potential (GWP) of 2.65 kg CO2 eq/m3 of freshwater produced, with operational electricity contributing 94% of this impact. Additional environmental impact categories assessed include acidification potential (AP), eutrophication potential (EP), freshwater aquatic ecotoxicity (FAE), abiotic depletion potential (ADP), and terrestrial ecotoxicity (TE). Operational electricity was the dominant contributor to all categories except ADP. Moreover, the use of platinum, ruthenium, and iridium in the electrode coating process significantly increased FAE and TE impacts. A sensitivity analysis of electricity sources reveals that replacing conventional electricity with renewable wind energy can reduce the GWP to 0.325 kg CO2 eq/m3. These findings highlight the potential of green energy in mitigating environmental impacts.