As(V) retention and As(III) simultaneous oxidation and removal on a MnO2-loaded polystyrene resin.
Based on KMnO4 oxidative capacity, a polystyrene matrix loaded with manganese dioxide was synthesized from an anionic commercial resin in chloride form. This medium, called R-MnO2, was tested for As(V) retention and for As(III) simultaneous oxidation and removal. Equilibrium was reached in 2 h and isotherms showed that R-MnO2 maximal capacities towards As(III) and As(V) are, respectively, 0.7 and 0.3 mmol/g. Various mechanisms were involved in As(III) retention: oxidation of H3AsO3(0) by MnO2(s) leading to the formation of HAsO4(2)- and Mn2+, fixation of As(V) formed on the resin beads and precipitation of Mn3(AsO4)2 with Mn2+ released. Successive arsenic desorption and retention steps were performed and showed that the quantity desorbed was low compared to the quantity removed during the first stage of the process. A second removal step, carried out under the same conditions as the first one, proved that the matrix second-removal capacity was weak. This solid sorbent, although not reusable, can be considered in field application as arsenic retention is really strong.
Lenoble
Véronique
V
Laboratoire des Sciences de l'Eau et de l'Environnement, Faculté des Sciences, 123 avenue Albert Thomas, 87 060 Limoges Cedex, France.
Laclautre
Christelle
C
Serpaud
Bernard
B
Deluchat
Véronique
V
Bollinger
Jean-Claude
JC