2.2. Purification and Activation of Strongly Basic Anionic Resin

Here, 6 g of dried IRA 402 resin was washed with ultrapure water in a 100 mL Berzelius flask. The washing process was repeated until the washing water was clear. The resin was kept in water to swell. When the noises produced by the expansion of the macromolecular network stopped, the resin was considered to be swollen. The resin was then quantitatively passed through a glass column—25 × 2.5 cm—height × internal diameter. The resin bed was activated with 30 mL of 4M HCl, which was allowed to flow through the column at a rate of 0.4 mL/min to activate all the functional groups of the resin, in the Cl⁻ ionic form. Finally, ultrapure water was passed through the column until a negative reaction for Cl⁻ ions was obtained in the effluent, verified with AgNO₃. In this way, the excess of Cl⁻ ions was released from the column and only the Cl⁻ ions are found inside the resin as mobile ions (counterions) for quaternary amino groups –N⁺(CH₃)₃. The mean properties of Amberlite IRA 402 resin are given in Table 1 [35].

Characteristic data for Amberlite IRA 402 resin.