Characterization of Cobalt Prussian Blue Analogue in Capacitive Deionization

Sammanfattning: Clean, drinkable water is nowadays taken for granted in most developed coun-tries. However, over two billion people in the world do not have access to drink-ing water. In an attempt to combat this, capacitive deionization (CDI) hasgained increased attention in recent years. CDI is an emergent method of de-salination through separation of ionic species in aqueous solutions. The perfor-mance of CDI is dependent on materials used and how the device is constructed.This paper investigates key metrics relating the efficiency and applicability oftwo different CDI materials, activated carbon (Zorflex FM10 Chemivron) andCobalt Prussian Blue Analogue (referred to as the active material), in regardsto the electrodes used. These metrics include energy consumption, energy re-covery and Faradaic efficiency. The results were gathered from building a circuitwith the CDI cell as the capacitor and switching the polarity of the cell when adefined threshold of the voltage (1.5 V) was reached. The energy consumptionof the activated carbon (0.450 kWh/m3) was found to be less than that of theactive material (1.45 kWh/m3). The energy recovery was found to be roughlyequal for both materials, 80.6 % for the activated carbon and 79.5 % for theactive material. Finally, the activated carbon had a Faradaic efficiency of 0.75while the active material had 1.8.