Sajwan, K. S. and Evangelou, V.P. and Lumbanraja, Jamalam (1994) A Gasometric Technique for Evaluating Kinetic Stability and Apparent Activation Energies of Manganese Oxide Minerals. Soil Science, 157 (1). pp. 19-25. ISSN 0038-075X

Text Lumbanraja Soil Science Volume 157 issue 1 1994 [doi 10.1097%2F00010694-199401000-00004].pdf - Published Version Restricted to Registered users only Download (469kB)

Abstract

Reduction-dissolution kinetics and apparent activation energies (Ea) of reagent grade [beta]-MnO2 (Fisher Scientific, Fair Lawn, NJ), [beta]-MnO2 (Ward's Earth Science, Rochester, NY pyrolusite), and MnOOH (Ward's Earth Science, Rochester, NY manganite) were determined by continuous gasometric analysis employing an isothermal automanometric apparatus. This method was based on pseudo-first-order kinetics of oxygen gas (O2) evolution by reducing the Mn(IV) and/or Mn(III) to Mn(II). The manganese oxide reduction was carried out employing a solution mixture of 2.4% H2O2 and 9.7% concentrated H2SO4 on a volume basis. The pseudo-first-order constant (k) at 21[degrees]C was 0.66 min-1 for reagent grade [beta]-MnO2, 1.68 min-1 for pyrolusite ([beta]-MnO2), and 0.009 min-1 for manganite (MnOOH). The apparent activation Ea were determined to be 35.56 kJ/mol-1 for reagent grade [beta]-MnO2, 29.95 kJ/mol-1 for pyrolusite ([beta]-MnO2), and 44.75 kJ mol-1 for manganite (MnOOH). The most kinetically stable manganese oxide species of the three minerals tested was MnOOH (manganite).

Item Type:	Article
Subjects:	S Agriculture > S Agriculture (General)
Divisions:	Fakultas Pertanian (FP) > Prodi Ilmu Tanah
Depositing User:	Prof.Dr.Ir Jamalam Lumbanraja
Date Deposited:	17 Nov 2016 03:49
Last Modified:	17 Nov 2016 03:49
URI:	http://repository.lppm.unila.ac.id/id/eprint/1190

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