Fig. 1: CDI concept for agricultural irrigation water treatment.
From: Long-lasting, monovalent-selective capacitive deionization electrodes
a Schematic of a CDI cell fed with water containing excessive Na+ which must be treated for direct use in irrigation. The cell is charged at an applied cell voltage Vch at or above 1 V and for a time tch significantly shorter than the time to reach equilibrium, teq. b The cathode nanopore is functionalized with strong-acid sulfonic groups, which enhances the preferential storage of monovalent Na+ over divalent Ca2+ at short charging times. Use of stable sulfonic (SO3−) groups and charging to short times minimizes Faradaic side reactions and thus electrode degradation. c The treated water has significantly reduced sodium absorption ratio (SAR) and ionic conductivity, rendering it suitable for direct use in irrigation.
