Abstract: The method includes a process of (i) and a process of (ii) in this order. In the process of (i), the potential of a first anode and the potential of a first cathode are adjusted in an aqueous solution containing chloride ions so as to increase the concentration of free chlorine in the aqueous solution. In the process of (ii), the potential of a second anode and the potential of a second cathode are adjusted in the aqueous solution so as to decrease the concentration of free chlorine in the aqueous solution. The difference between the potential of the second anode and the potential of the second cathode in the process of (ii) is smaller than the difference between the potential of the first anode and the potential of the first cathode in the process of (i).

Abstract: The method includes a process of (i) and a process of (ii) in this order. In the process of (i), the potential of a first anode and the potential of a first cathode are adjusted in an aqueous solution containing chloride ions so as to increase the concentration of free chlorine in the aqueous solution. In the process of (ii), the potential of a second anode and the potential of a second cathode are adjusted in the aqueous solution so as to decrease the concentration of free chlorine in the aqueous solution. The difference between the potential of the second anode and the potential of the second cathode in the process of (ii) is smaller than the difference between the potential of the first anode and the potential of the first cathode in the process of (i).

Abstract: The portable device of the present invention for regulating the hardness of drinking water includes a collapsible electrode group (20) including ion-adsorbing electrodes (21) and (22) and a power supply (13) for applying a voltage between the ion-adsorbing electrode (21) and the ion-adsorbing electrode (22). The first ion-adsorbing electrode (21) includes a first electrically conductive material capable of adsorbing ions. The second ion-adsorbing electrode includes a second electrically conductive material capable of adsorbing ions. In an example, a voltage is applied between the first ion-adsorbing electrode (21) and the second ion-adsorbing electrode (22), with the first and second ion-adsorbing electrodes (21) and (22) being immersed in the drinking water (25). The applied voltage regulates the amount of ions adsorbed on the first and second electrically conductive materials, and thereby the hardness of the drinking water is regulated.

Abstract: The disinfection method of the present invention includes steps (i) and (ii). In step (i), a voltage is applied, in an aqueous liquid (21), between a counter electrode (13) and a first ion-adsorbing electrode (11) containing a first electrically conductive material (11a) capable of adsorbing an ion reversibly, thereby changing a pH of the aqueous liquid (21) to a value less than 5 or to a value greater than 9. In step (ii), the pH of the aqueous liquid 21 is adjusted to a range of 5 to 9.

Abstract: The portable device of the present invention for regulating the hardness of drinking water includes a collapsible electrode group (20) including ion-adsorbing electrodes (21) and (22) and a power supply (13) for applying a voltage between the ion-adsorbing electrode (21) and the ion-adsorbing electrode (22). The first ion-adsorbing electrode (21) includes a first electrically conductive material capable of adsorbing ions. The second ion-adsorbing electrode includes a second electrically conductive material capable of adsorbing ions. In an example, a voltage is applied between the first ion-adsorbing electrode (21) and the second ion-adsorbing electrode (22), with the first and second ion-adsorbing electrodes (21) and (22) being immersed in the drinking water (25). The applied voltage regulates the amount of ions adsorbed on the first and second electrically conductive materials, and thereby the hardness of the drinking water is regulated.

Abstract: In the process of the present invention, first, voltage is applied between an electroconductive substance (11) capable of adsorbing ions and a counter electrode (12) in an aqueous solution (20) containing at least one type of ions (L) other than hydrogen ions and hydroxide ions, so that at least a part of the ions (L) contained in the aqueous solution (20) are allowed to be adsorbed on the electroconductive substance (11). Subsequently, the electroconductive substance (11) is removed from the aqueous solution (20) and then is washed.

Abstract: In the method of the present invention, in an aqueous solution 20 containing at least one type of ions (L) other than hydrogen ions and hydroxide ions, voltage is applied between an ion-adsorbing electrode 11 containing an electrically conductive material (C1) capable of adsorbing ions and an ion-adsorbing electrode 12 containing an electrically conductive material (C2) capable of adsorbing ions so that the ion-adsorbing electrode 11 serves as an anode. Thus the electrically conductive material (C1) is allowed to adsorb an anion contained in the aqueous solution 20 and the electrically conductive material (C2) is allowed to adsorb a cation contained in the aqueous solution 20. Subsequently, in a liquid 30 containing water, voltage is applied between either the ion-adsorbing electrode 11 or the ion-adsorbing electrode 12 and counter electrode 13 or 14, resulting in changing the pH of the liquid 30.

Abstract: In a container 10, a first electrode 11 containing a first electrically conductive material capable of adsorbing an ion and a second electrode 12 containing a second electrically conductive material capable of adsorbing an ion are immersed in a liquid (aqueous solution 13) containing at least one type of ion other than hydrogen ion and hydroxide ion. Then a voltage is applied between the first electrode 11 and the second electrode 12 so that the first electrode 11 serves as an anode. This voltage application allows the first electrode 11 and the second electrode 12 to adsorb anions and cations contained in the aqueous solution 13, respectively. In this ion adsorption step, the aqueous solution 13 is treated by a batch method. The voltage to be applied is higher than a voltage that causes electrolysis of a solvent of the solution, assuming that no voltage drop is caused by the liquid (aqueous solution 13).