Varada Menon Palakkal, Juan Rubio & Prof. Chris Arges Published in ACS Sustainable Chemistry & Engineering

Congratulations go to Varada Menon Palakkal (PhD candidate), Juan Rubio (BS ChE 2018), and Professor Arges for publishing a research article in ACS Sustainable Chemistry and Engineering entitled ‘Low resistant ion-exchange membranes for energy efficient membrane capacitive deionization’. This paper correlates ion-exchange membrane resistance values to the energy efficiency of membrane capacitive deionization (MCDI) – an electrosorption technology used in ionic separations. MCDI has emerged as an energy efficient technology for brackish water desalination and is important in industrial water reclamation. The study showed that a 5 to 10 fold reduction in area specific resistance of the ion-exchange membranes, achieved through new polymer membrane chemistries, only translated to a 50% reduction in energy expended per ion removed – still a laudable outcome. The discrepancy between the 5-10 fold reduction resistance and a 2 fold improvement in energy efficiency of the MCDI cell was investigated using electrochemical impedance spectroscopy. Fitting of impedance data to a transmission line equivalent circuit model revealed that spacer channel resistance dominated the cell efficiency when membrane resistances have been minimized and the spacer channel resistance hindered further energy efficiency improvement in MCDI. These results motivate future studies by Ms. Menon Palakkal and Prof. Arges to address spacer channel resistances in MCDI.

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