Manganese oxide, oxidizing phenolic

Hu, B., Chen, C., Frueh, S.J., Jin, L., Joesten, R. and Suib, S.L. (2010) Removal of aqueous phenol by adsorption and oxidation with doped hydrophobic cryptomelane-type manganese oxide (K-OMS-2) nanofibers. Journal of Physical Chemistry C, 114, 9835-9844. 

Hydrous Manganese oxides, widely distributed in natural systems, are stronger oxidants than iron(III)(hydr)oxide. These oxides readily oxidize many natural and xenobiotic organic compounds. Various substituted phenols, naturally present in... 

Oxidation of phenolic acids by soil iron and manganese oxides. Soil Sci. Soc. 

In natural anoxic environments, the major alternative oxidants are iron(III) and manga-nese(IV) oxides and hydroxides. Both are common in natural systems, as crystalline or amorphous particles or coatings on other particles. In the absence of photocatalysis, however, iron and manganese oxides are weak oxidants. As a result, they appear to react at significant rates only with phenols and anilines (45, 59-64). 

Ukrainczyk, L. and M.B. McBride. 1992. Oxidation of phenol in acidic aqueous suspensions of manganese oxides. Clays Clay Miner. 40, 157-166. 

In the absence of a catalyst, Mn(iv), Mn(iii) and Mn(ii) are interconverted by ROS such as H2O2 and 02 through a complex set of redox reactions [218-220,229]. Manganese oxides also are reduced by humic substances, probably through reactions with phenolic moieties [231] and the reaction rate is enhanced by light [196,226,230-234]. As a consequence of this reduction of MnOx, there is a surface maximum of soluble Mn(ii) in the open ocean that helps... 

As an example, in Table 6, the pseudo-first-order rate constants determined by Jafvert and Wolfe (1987) are given for the disappearance of some polyhalo-genated ethanes in an anaerobic sediment-water mixture. For all compounds, the most important reaction mechanism was found to be vicinal dehalogenation (reaction 8 in Table 1). As can be seen, in this system, an appreciable fraction of all compounds (particularly, the hydrophobic compound hexachloroethane) was present in the sorbed form. We should note, however, that unlike the case of surface complexation of hydrophilic compounds at oxide surfaces, (e.g., ill encountered in the oxidation of phenols by manganese oxides, see Stone, 1987),... 

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