Heterogeneous decomposition of H2O2 over Mn-doped Mg [OH] 2 prepared by co-precipitation

ABSTRACT

H2O2 over Mn-doped Mg [OH]2 was precipitated from a common salt solution containing Mn2+ and Mg2+ ions by the addition of alkali; final solids contained 1.36, 0.36, 0.23 and 0.088 wt% of Mn. Kinetic curves were determined at varying contents of Mn, weight of carrier, initial H2O2 concentrations and temperatures. First-order reaction law equations were applied satisfactorily in the full-range of decomposition curves. A wide spectrum of differently active catalysts were obtained, depending above all on the Mn-content per weight unit. Experiments with H2O2 concentrations of 0.27-1.20 M showed variable t50 and t90 values. However, the overall rate constant [K0] showed no definite pattern. Decomposition over 2 catalysts was associated with Ea-41.1 and 44.2 Kj mol-1. A satisfactory linear log-log correlation holds between Ko and t90