Removal of F−, NO3−, and PO43− ions from aqueous solution by aminoclays

Fluoride (F−), nitrate (NO3−), and phosphate (PO4n−) anions are produced in large quantities by the use of cleaning agents in the electronics industry. Because of their high solubility in water and harmful impact on the environment, the development of an efficient treatment process for anionic species has been gaining increased attention. In this study, aminoclays with centered cationic metal ions, including Mg2+, Al3+, and Fe3+, were synthesized by a one-pot sol-gel reaction, and removal of F−, NO3−, and PO43− by the synthesized aminoclays was evaluated in an anion mixture system. The aminoclays resulted in exfoliated dispersions with high-density amino groups in aqueous solution. Among the anions studied, phosphate was preferentially removed by the aminoclays, which suggests that anion removal by aminoclays was mainly achieved by the electrostatic interactions between anions and aminoclays. Compared with aminopropyl-functionalized silica gel (average diameter: 40–63 μm), aminoclays showed higher anion removal efficiencies.