Use of deep sea manganese nodules as catalysts for reduction of nitric oxide with ammonia

Wu, Shao-Chun; Chu, Chieh

doi:10.1016/0004-6981(72)90198-9

Cited by 11 publications

(3 citation statements)

References 2 publications

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“…Birnessite is a common manganese oxide mineral, existing in a variety of geological settings including deep sea nodules, terrestrial ore deposits, and surface coatings and crusts. − It is also a significant component of some soils and involved in ion-exchange processes and redox reactions related to groundwater chemistry − The layer spacing ranges from between 6.9 to 7.0 Å. − In their natural form, birnessites show potential applications as heterogeneous catalysts in the reduction of NO in the presence of ammonia, oxidation of CO, and hydrogenation of alkenes . Birnessite is also a useful material for nuclear waste absorption due to its microporosity. , Ion-exchange and redox properties make birnessite an interesting cathode material − for rechargeable batteries.…”

Section: Introductionmentioning

confidence: 99%

Syntheses of Birnessites Using Alcohols as Reducing Reagents: Effects of Synthesis Parameters on the Formation of Birnessites

Luo

Suib

1999

Chem. Mater.

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This study shows that synthetic birnessite, an octahedral layered manganese oxide material called OL-1 can be synthesized with Na + , K + , Na + /Mg 2+ , or K + /Mg 2+ ions as interlayer cations by redox reactions between permanganate and alcohols in a strong basic media. The synthesis processes were followed by powder X-ray diffraction (XRD) studies. OL-1 samples have been characterized by XRD, chemical analysis, average oxidation states measurements, and scanning electron microscopy studies. Results show that all OL-1 samples have an interlayer spacing of ∼7.0 Å. The average oxidation states of manganese fall in a range of 3.60-3.70. The chemical compositions for typical Na-OL-1 and K-OL-1 are Na 4.7 Mn 14 O 27.7 ‚8.7H 2 O and K 4.6 Mn 14 O 27.9 ‚6.6H 2 O, respectively. R-MnO(OH) coexists with Na-OL-1 in the synthesis where NaMnO 4 aqueous solution is added to the solution containing ethanol, water, and sodium hydroxide. When Mg(MnO 4 ) 2 was used as the oxidant, more Mg 2+ ions were accommodated in OL-1 than in previous reports. The interlayer space is propped opened by intercalating hexylammonium ions between the layers, confirming the layered structure.

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Section: Introductionmentioning

confidence: 99%

Syntheses of Birnessites Using Alcohols as Reducing Reagents: Effects of Synthesis Parameters on the Formation of Birnessites

Luo

Suib

1999

Chem. Mater.

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“…Once initiated nodule formation is self-perpetuating because Fe and Mn are autocatalytically precipitated on the surface (2). Indeed Mn oxides, and Mn nodules themselves, have been recommended as oxidation catalysts for automobile exhaust systems (21) and for the reduction of nitric acid pollutants (22). It also has been proposed that in some environments bacteria might be the dominant catalysts for Mn oxide precipitation (7).…”

Section: Ocean Mn Nodulesmentioning

confidence: 99%

Manganese oxide minerals: Crystal structures and economic and environmental significance

Post

1999

Proc. Natl. Acad. Sci. U.S.A.

1,504

1,182

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Manganese oxide minerals have been used for thousands of years-by the ancients for pigments and to clarify glass, and today as ores of Mn metal, catalysts, and battery material. More than 30 Mn oxide minerals occur in a wide variety of geological settings. They are major components of Mn nodules that pave huge areas of the ocean f loor and bottoms of many fresh-water lakes. Mn oxide minerals are ubiquitous in soils and sediments and participate in a variety of chemical reactions that affect groundwater and bulk soil composition. Their typical occurrence as fine-grained mixtures makes it difficult to study their atomic structures and crystal chemistries. In recent years, however, investigations using transmission electron microscopy and powder x-ray and neutron diffraction methods have provided important new insights into the structures and properties of these materials. The crystal structures for todorokite and birnessite, two of the more common Mn oxide minerals in terrestrial deposits and ocean nodules, were determined by using powder x-ray diffraction data and the Rietveld refinement method. Because of the large tunnels in todorokite and related structures there is considerable interest in the use of these materials and synthetic analogues as catalysts and cation exchange agents. Birnessite-group minerals have layer structures and readily undergo oxidation reduction and cation-exchange reactions and play a major role in controlling groundwater chemistry.

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“…Weisz (1968) has reported on Pacific Ocean nodules as catalysts for the combustion of carbon monoxide, methane, and butane. Wu and Chu (1972) have studied the use of nodules and catalysts for the reduction of nitric oxide with ammonia.…”

mentioning

confidence: 99%

Manganese Nodules as Demetalation Catalysts

Chang¹,

Silvestri²

1974

Ind. Eng. Chem. Proc. Des. Dev.

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Manganese nodules have been found both on ocean floors (Menand and Shipek, 1958) and in fresh water (Schoettle and Friedman, 1971). Their relatively high surface areas and transition metal oxide content has aroused interest in their catalytic properties. Weisz (1968) has reported on Pacific Ocean nodules as catalysts for the combustion of carbon monoxide, methane, and butane. Wu and Chu (1972) have studied the use of nodules and catalysts for the reduction of nitric oxide with ammonia.

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Use of deep sea manganese nodules as catalysts for reduction of nitric oxide with ammonia

Cited by 11 publications

References 2 publications

Syntheses of Birnessites Using Alcohols as Reducing Reagents: Effects of Synthesis Parameters on the Formation of Birnessites

Syntheses of Birnessites Using Alcohols as Reducing Reagents: Effects of Synthesis Parameters on the Formation of Birnessites

Manganese oxide minerals: Crystal structures and economic and environmental significance

Manganese Nodules as Demetalation Catalysts

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