Manganese oxides, deposition

In kaolin (clay) processing, sulfur dioxide reduces colored impurities, eg, iron compounds. In the bromine industry, sulfur dioxide is used as an antioxidant in spent brine to be reinjected underground. In agriculture, especially in California, sulfur dioxide is used to increase water penetration and the avadabiHty of soil nutrients by virtue of its abiHty to acidulate saline—alkaH soils (327). It is also usefiil for cleaning ferric and manganese oxide deposits from tile drains (328). 

Black dendrites in rocks are formed from manganese oxide depositions. 

Hem J. D., Roberson C. E., and Fournier R. B. (1982). Stability of -MnOOH and manganese oxide deposition from spring water. Water. Resour. Res., 18 563-570. 

A thin film of manganese oxides deposited over a glassy earbon electrode dramatically lowers the overpotential for oxidation of various hydrazines ad hydrogen peroxide, thereby facilitating their amperometric detection in flow systems. Sensors based on this principle are highly sensitive and provide... 

OMS and OL materials may also find applications in areas presently employing conventional manganese oxide materials such as electrolytic manganese oxide (deposition at electrode surfaces), dry cell batteries, production of ferrites, as components of oxidation catalysts, and for crosslinking of rubber. 104 potential applications in separation science,105 environmental catalysis,106 and biological systems 107 may also be possible. Other possibilities include use as sensors,100 as supports for metal clusters, 109 and in disposal of radioactive metal ions.H0... 

Lalou, C., Brichet, E., Jehanno, C. and Perez-Leclaire, H., 1983. Hydrothermal manganese oxide deposits from Galapagos mounds, DSDP Leg 70, hole 509B and Alvin dives 729 and 721. Earth and Planetary Science Letters, 63 63-75. 

Some concepts of nonequilibrium thermodynamics may be useful to develop further the proposed model. For the manganese oxide deposition process to continue, the oxidation (Equation 3) and disproportionation steps (Equation 2) must each have a favorable chemical potential, or positive reaction aflBnity, A. The reaction aflBnity is equivalent to the chemical potential but opposite in sign, and can be defined 17) as... 

Liang, C. H., and C. S. Hwang. 2010. Effects of temperatures and cations of electrolyte on the capacitive characteristics of the manganese oxide deposited by hydrothermal electrochemical method. Journal of Alloys and Compounds 500 102-107. 

Manganese and iron oxidation are coupled to cell growth and metabolism of organic carbon. Microbially deposited manganese oxide on stainless and mild steel alters electrochemical properties related to the potential for corrosion. Iron-oxidizing bacteria produce tubercles of iron oxides and hydroxides, creating oxygen-concentration cells that initiate a series of events that individually or collectively are very corrosive. 

Both Linhardt and Dickinson et al." demonstrated that microbi-ologically deposited manganese oxide on stainless and mild steel coupons in fresh water (Fig. 4) caused an increase in Ecorr and increased cathodic current density at potentials above -200 mYscE-" Biomineralization of... 

Hu CC, Tsou TW. Capacitive and textural characteristics of hydrous manganese oxide prepared by anodic deposition. Electrochim. Acta 2002 47 3523-3532. 

The importance of bacteria in mediating Mn(II) oxidation in certain environments is evident. But, the mechanisms whereby bacteria oxidize Mn(II) are poorly understood. Some bacteria synthesize proteins or other materials that enhance the rate of Mn(II) oxidation (.52). Other strains of bacteria require oxidized manganese to oxidize Mn(II) (53), suggesting that they may catalyse the oxidation of Mn(II) on the manganese oxide surface. Other bacteria may catalyse the oxidation of Mn(II) on iron oxide surfaces, as iron is associated with manganese deposits on bacteria collected in the eastern subtropical North Pacific (54). 

Two types of metal-rich hydrogenous deposits are formed on the seafloor iron-manganese oxides and polymetallic sulfides. The iron-manganese oxides have been deposited as nodules, sediments, and crusts. They are enriched in various trace elements, such as manganese, iron, copper, cobalt, nickel, and zinc, making them a significant repository for some of these metals. Most of the metals in the polymetallic sulfides are of hydrothermal origin. These sulfides have been deposited as metalliferous sediments aroimd hydrothermal systems and as rocks that infill cracks within former... 

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