Development and characterization of yttrium-ferric binary composite for treatment of highly concentrated arsenate...

Highly concentrated arsenic generated from industrial operation processes has posted a great thrust to humans. In this study, yttrium-ferric binary composite prepared through a simple co-precipitation method and applied for removing highly concentrated arsenic from the simulated arsenic-containing water. An optimal molar ratio of Y/Fe was determined as 8:1, which had a point of zero charge of around 7.0. The yttrium-ferric binary composite was aggregated by the nano-sized particles. The chemical state of yttrium and iron in the adsorbent was + III. The maximum adsorption capacities of the adsorbent towards arsenate (As(V)) were 401.8 mg-As/g at pH 4 and 288.7 mg-As/g at pH 7, respectively. A contact time of 8 h was sufficient to achieve 80% of the ultimate removal, faster than many reported/commercial water treatment materials. The existence of fluoride and phosphate ions significantly retarded the uptake of arsenic, indicating that likely the adsorbent was capable of adsorbing both contaminants. The mechanism study with several tools such as X-ray photoelectron spectroscopy (XPS) indicated that such functional groups as hydroxyl and carbonate groups participated in the As(V) adsorption process via ligand exchange followed by the inner-sphere complexation.