Removal of As(V) Ions from Solution by Akaganeite bgr-FeO(OH) Nanocrystals

The original method is developed for producing the new inorganic sorption material of akaganeite bgr-FeO(OH). The material in question is characterized relative to arsenic contained in aqua. The possibility is established for removing arsenate ions from water by contemporary physicochemical methods.     

Effect of Cationic Surfactant on the Adsorption of Arsenites onto Akaganeite Nanocrystals

Abstract

The current research focuses on removal of arsenite ions from aqueous solutions by a new adsorbent, surfactant modified akaganeite (Ak_m), prepared after the adsorption of the cationic surfactant, hexadecyl trimethyl ammonium bromide (N‐Cetyl‐N,N,N‐Trimethylammonium Bromide) onto akaganeite. The new adsorbent was investigated with Fourier transform infrared spectra and X‐ray photoelectron spectroscopy methods for a better understanding of the effects of surface properties on arsenite adsorption. Surfactant modified akaganeite was found to be an effective adsorbent for the removal of arsenite ions from aqueous systems. It presented a significantly higher arsenite adsorption capacity than the pure nanocrystalline akaganeite. Kinetics of adsorption obeys a second‐order rate equation. The maximum adsorption capacity was found to 328.3 mg g^?1 over a wide pH range significantly higher than those of other adsorbents reported.     

Buried iron archaeological artefacts: Corrosion mechanisms related to the presence of Cl-containing phases

Deterioration after excavation of archaeological iron artefacts buried in soil is often associated with the presence of Cl-containing phases in corrosion products, leading to serious problems for conservation of metallic objects of cultural heritage. Thus, in order to better understand the corrosion process related to the presence of chlorine, some high-resolution techniques of materials characterisation are implemented. Particularly this paper shows the great utility of the combination of micro-X-ray diffraction, micro-Raman spectroscopy and micro-X-ray absorption spectroscopy. The analyses are realised on the cross sections of iron corroded objects excavated on archaeological sites dated from the 12th to the 16th century AD. In addition to the common oxyhydroxide containing chloride, akaganeite (β-FeOOH) often mentioned in the literature, a ferrous hydroxychloride β-Fe₂(OH)₃Cl was also found in the corrosion layers. In order to explain the corrosion system formed during burial, a corrosion mechanism including the presence of chlorine, is proposed.