Arsenates Sorption by Nanocrystalline Hybrid Surfactant-Akaganéite

Abstract

The scope of this study was to evaluate an innovative adsorbent, nanocrystalline hybrid surfactant-akaganéite (denoted as Ak_h), for arsenate ions removal from dilute solution. Ak_h was synthesized in the laboratory using FeCl₃ as the precursor and a cationic surfactant, hexadecyl-trimethylammonium bromide, as modifier. Ak_h presented a significantly higher arsenate adsorption capacity (about 180 mg As(V)/g) than the pure nanocrystalline akaganéite (denoted as Ak, about 120 mg As(V)/g). The kinetics of adsorption obeyed a pseudo-second-order rate equation. Higher ionic strength results in higher arsenate adsorption. The new adsorbent was investigated with X-ray powder diffraction, N₂ adsorption-desorption (BET), Fourier transform infrared spectra, and X-ray photoelectron spectroscopy methods for better understanding the effects of surface properties on arsenate adsorption.

Keywords:

• akaganéite
• arsenates
• FTIR
• sorption
• XPS