Manganese in nature

Morgan, J. J. (1967). Chemical equilibria and kinetic properties of manganese in natural waters. In "Principles and Applications of Water Chemistry" (S. D. Faust and J. V. Himter, eds), pp. 561-623. Wiley, New York. 

Table VIII. Removal times for manganese in natural waters.

Morgan, J.J. 2000. Manganese in natural waters and earth s crust Its availability to organisms. Met. Ions Biol. Syst. 37 1-34. 

Reductive dissolution kinetics of Mn02 (MnlV) and MnOOH (Mnlll) are presented below for demonstration purposes. The chemistry of manganese in nature is rather complex because three oxidation states are involved [Mn(II), Mn(III), and Mn(FV)] and form a large number of oxides and oxyhydroxides with various degrees of chemical stability (Bricker, 1965 Parc etal., 1989 Potter and Rossman, 1979a,b). One... 

By far the most important role of manganese in nature is its direct involvement in the photocatalytic, four-electron oxidation of water to dioxygen in green plant photosynthesis, an essential process for the maintenance of life. Pirson, in 1937, first discovered the requirement of manganese in photosynthesis by showing that plants grown in a Mn-deficient medium lost their water oxidation capacity (184). During the next four decades, several researchers showed that two photosystems, photosystem I (PSI) and photosystem II (PSII), were involved in photosynthesis and that 02 evolution and Mn were localized at PSII (for a review, see Ref. 185). 

Morgan, J.J. Chemical equilibria and kinetic properties of manganese in natural waters, p. 561-624, Faust, S.D., Hunter, J.V., eds. "Principles and Application of Water Chemistry." John Wiley and Sons, New York, N.Y., 1965. 

An extensive survey of the thermodynamic and kinetic properties of manganese in natural aqueous systems has been presented by Morgan (3). From a thermodynamic standpoint, Mn(II) is unstable with respect to oxidation in natural waters. The kinetics of the oxidation reactions are sufficiently slow so that Mn(II) can exist as a metastable species in natural waters. The solubility of Mn(II) in most natural systems probably is limited by the solubility of MnC03. Soluble complexes such as MnHCCV make varying contributions to the total soluble Mn(II) species in natural waters. Some of the equilibria which are relevant to this study are listed in Table I. 

Alternatively, the oxidising or reducing solid reagent can be immobilised on a suitable support, as demonstrated in the spectrophotometric and chemiluminometric flow injection determinations of manganese in natural waters using mini-columns of lead(IV) dioxide or sodium bis-muthate immobilised on silica gel beads [112] and paper pulp [113], respectively. 

J.F. van Staden, L.G. Kluever, Determination of manganese in natural water and effluent streams using a solid-phase lead(IV) dioxide reactor in a flow-injection system, Anal. Chim. Acta 350 (1997) 15. 

Dieter HH, Rotard W, Simon J, et al. 1992. Manganese in natural mineral waters from Germany. Die Nahrung 5 488-484. 

M. F. Gin6, E. A. G. Zagatto, and H. Bergamin F , Semiautomatic Determination of Manganese in Natural Waters and Plant Digests by Flow Injection Analysis. Analyst, 104 (1979) 371. 

Manganese in Natural Waters and Earth s Cmst. Its Availability to Organisms... 

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