?Recovery of manganese oxides from spent alkaline and Zn/C batteries. An application as catalyst for VOCs elimination?

MARIA VICTORIA GALLEGOS; LORENA FALCO; MIGUEL A PELUSO; JORGE SAMBETH; HORACIO J THOMAS

WASTE MANAGEMENT (ELMSFORD)

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2013 vol. 33 p. 1483 - 1490

0956-053X

Manganese, in the form of oxide, was recovered from spent alkaline and zinc?carbon batteries employinga biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acidreducingmedium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur);a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor.Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis(EMO) and the other by a chemical precipitation with KMnO4 solution (CMO). The non-leached solid residuewas also studied (RMO). The solids were compared with a MnOx synthesized in our laboratory.The characterization by XRD, FTIR and XPS reveal the presence of Mn2O3 in the EMO and the CMO samples,together with some Mn4+ cations. In the solid not extracted by acidic leaching (RMO) the main phasedetected was Mn3O4.The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane.Complete conversion of ethanol occurs at 200 C, while heptane requires more than 400 C. The CMO hasthe highest oxide selectivity to CO2.The results show that manganese oxides obtained using spent alkaline and zinc?carbon batteries asraw materials, have an interesting performance as catalysts for elimination of VOCs.