Fig. 8: Process of HIAO/225H material synthesis.

A plastic column with a diameter of 1 cm, cation exchange resin: 5 g, adding HCl into the natural alum-ferric water with a dose of 1 mL L⁻¹, a flow rate of 3 L h⁻¹, ammonia solution: 100 mL of deionized water containing 1 mL of ammonia solution (28–34 vol%), NaOH solution (0.1 M).