▎ 摘　　要

NOVELTY - Monovalent ionic species are selectively separated from an ionic solution (111) by (a) passing the ionic solution comprising a positively charged monovalent ion and a positively charged polyvalent ion, through an electrode capacitor assembly (101) comprising first electrode (103) and second electrode (105), where electrodes comprise nanoporous carbon, and first electrode is modified with sulfonate surface groups, and at least one flow channel (107) for the passage of the solution; and (b) charging electrode capacitor assembly: (1) at a voltage of at least about 1.5 V; and/or (2) for a scaled charging time of less than about 2, providing enhanced adsorption of the positively charged monovalent ion in the first electrode as compared to the adsorption of the positively charged polyvalent ion. USE - Selective separation of monovalent ionic species from an ionic solution for treating agricultural water designated for irrigation. ADVANTAGE - The method allows to reduce the concentration of positively charged monovalent ions such as sodium ions, while maintaining the desired concentration of positively charged polyvalent ions, such as calcium ions. The combination of the simple design of the capacitive deionization (CDI) and the easy to implement method provide a cost- and energy-efficient solution for water treatment applications in which selective separation of monovalent ionic species is required. DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of the electrode capacitor assembly and the ionic solution. Ionic solution (111) Capacitor electrode assembly (101) First electrode (103) Second electrode (105) Flow channel (107)