1 research outputs found
Tetravalent Manganese Feroxyhyte: A Novel Nanoadsorbent Equally Selective for As(III) and As(V) Removal from Drinking Water
The
development of a single-phase Fe/Mn oxy-hydroxide (Ī“-Fe<sub>0.76</sub>Mn<sub>0.24</sub>OOH), highly efficient at adsorbing both
AsĀ(III) and AsĀ(V), is reported. Its synthesis involves the coprecipitation
of FeSO<sub>4</sub> and KMnO<sub>4</sub> in a kilogram-scale continuous
process, in acidic and strongly oxidizing environments. The produced
material was identified as a manganese feroxyhyte in which tetravalent
manganese is homogeneously distributed into the crystal unit, whereas
a second-order hollow spherical morphology is favored. According to
this structuration, the oxy-hydroxide maintains the high adsorption
capacity for AsĀ(V) of a single Fe oxy-hydroxide combined with enhanced
AsĀ(III) removal based on the oxidizing mediation of MnĀ(IV). Ion-exchange
between arsenic species and sulfates as well as the strongly positive
surface charge further facilitate arsenic adsorption. Batch adsorption
tests performed in natural-like water indicate that MnĀ(IV)-feroxyhyte
can remove 11.7 Ī¼g AsĀ(V)/mg and 6.7 Ī¼g AsĀ(III)/mg at equilibrium
pH 7, before residual concentration overcomes the regulation limit
of 10 Ī¼g As/L for drinking water. The improved efficiency of
this material, its low cost, and the possibility for scaling-up its
production to industry indicate the high practical impact and environmental
importance of this novel adsorbent