scholarly journals Capacity of Chlorate to Oxidize Ferrous Iron: Implications for Iron Oxide Formation on Mars

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 729 ◽  
Author(s):  
Kaushik Mitra ◽  
Eleanor Moreland ◽  
Jeffrey Catalano
Keyword(s):  
Iron Oxide ◽  
Mass Balance ◽  
Iron Oxides ◽  
Ferrous Iron ◽  
Effective Capacity ◽  
Fluid Type ◽  
Oxide Formation ◽  
Solution Ph ◽  
Strong Potential ◽  
Initial Mineral

Chlorate is an important Cl-bearing species and a strong potential Fe(II) oxidant on Mars. Since the amount of oxychlorine species (perchlorate and chlorate) detected on Mars is limited (<~1 wt.%), the effectiveness of chlorate to produce iron oxides depends heavily on its oxidizing capacity. Decomposition of chlorate or intermediates produced during its reduction, before reaction with Fe(II) would decrease its effective capacity as an oxidant. We thus evaluated the capacity of chlorate to produce Fe(III) minerals in Mars-relevant fluids, via oxidation of dissolved Fe(II). Each chlorate ion can oxidize 6 Fe(II) ions under all conditions investigated. Mass balance demonstrated that 1 wt.% chlorate (as ClO3−) could produce approximately 6 to 12 wt.% Fe(III) or mixed valent mineral products, with the amount varying with the formula of the precipitating phase. The mineral products are primarily determined by the fluid type (chloride- or sulfate-rich), the solution pH, and the rate of Fe(II) oxidation. The pH at the time of initial mineral nucleation and the amount of residual dissolved Fe(II) in the system exert important additional controls on the final mineralogy. Subsequent diagenetic transformation of these phases would yield 5.7 wt.% hematite per wt.% of chlorate reacted, providing a quantitative constraint on the capacity of chlorate to generate iron oxides on Mars.

scholarly journals Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ryosuke Sinmyo ◽  
Elena Bykova ◽  
Sergey V. Ovsyannikov ◽  
Catherine McCammon ◽  
Ilya Kupenko ◽  
...  
Keyword(s):  
Applied Sciences ◽  
Crystal Structure ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Industrial Applications ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Insight Into

Abstract Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary iron oxides known to date. The synthesis of Fe7O9 opens a new portal to exotic iron-rich (M,Fe)7O9 oxides with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new iron oxide groups may provide new insight into the cycling of volatiles in the Earth’s interior.

Waste Plastic Sachet as Alternative Anti-Corrosion Filler for Iron Oxide in Resin Coatings

2021 ◽  
Vol 877 ◽  
pp. 9-14
Author(s):  
Francis Darwin T. Eugenio ◽  
Bryan B. Pajarito
Keyword(s):  
Corrosion Resistance ◽  
Iron Oxide ◽  
Film Thickness ◽  
Iron Oxides ◽  
Water Resistance ◽  
Inorganic Compounds ◽  
Environmental Issues ◽  
Metal Coatings ◽  
Waste Plastic ◽  
Coating Mixture

Iron oxides and similar inorganic compounds have served as anti-corrosion fillers for metal coatings. Environmental issues related to the mining of metallic fillers have stimulated interest in alternative fillers such as organic fillers. This paper explores the use of comminuted waste plastic sachets (WPS) as an anti-corrosion filler to resin-based metal coating. Mixture design of experiment was used to study the effect of iron oxide-WPS blends on the film thickness, viscosity, corrosion behavior, and water resistance of the coating. Results show that the film thickness was affected by the presence of iron oxide while the viscosity of the coating was affected by high loads of WPS. Among all coatings, the blend containing 25% iron oxide and 75% WPS produced the highest corrosion resistance. In conclusion, comminuted WPS provided additional corrosion resistance and could serve as an alternative anti-corrosion filler.

Preparation and application of magnetite nanoparticles immobilized on cellulose acetate nanofibers for lead removal from polluted water

2016 ◽  
Vol 17 (1) ◽  
pp. 176-187 ◽  
Author(s):  
Thanaa I. Shalaby ◽  
Marwa F. El-Kady ◽  
Abd El Halem M. Zaki ◽  
Soheir M. El-Kholy
Keyword(s):  
Iron Oxide ◽  
Cellulose Acetate ◽  
Iron Oxide Nanoparticles ◽  
Composite Nanofibers ◽  
Polluted Water ◽  
Oxide Nanoparticles ◽  
Lead Removal ◽  
Order Model ◽  
Solution Ph ◽  
Ft Ir

Novel magnetic cellulose acetate (CA) nanofibers were fabricated using an electrospinning process. Co-precipitated magnetite iron oxide nanoparticles were immobilized onto CA nanofibers at different weight ratios (0.2–2.5% wt/v) with a CA concentration of 15% (wt %), applied electric voltage of 20 kV, feeding rate of 1.5 ml/h and 7 cm distance between needle tip and collector. The prepared iron oxide nanoparticles were characterized using X-ray diffraction, a transmission electron microscope, a Fourier transform infrared spectrophotometer (FT-IR) and a vibrating sample magnetometer (VSM). The magnetic nanofibers were characterized by scanning electron microscopy, FT-IR, thermogravimetric analysis and VSM. The fabricated composite nanofibers were evaluated as a sorbent matrix for lead decontamination from aqueous solution using a batch technique. The influence of solution pH, contact time and adsorbent concentration on the removal efficiency was investigated. Adsorption kinetics models and isotherms were applied to the lead decontamination process onto the fabricated composite nanofibers. The kinetics of the sorption process revealed that the pseudo-second-order model fitted relatively better than the pseudo-first-order model. On the other hand, both the Langmuir and Freundlich isotherms gave a comparable fit to the adsorption data, with a high coefficient of regression of 0.999.

scholarly journals Morphological Analysis of Quartz Grains of Two Horizons in a Ultisol, Paraná – Brazil (Análise morfológica de grãos de quartzo de dois horizontes de Argissolos, Paraná – Brasil)

2017 ◽  
Vol 10 (4) ◽  
pp. 1059
Author(s):  
Fabiana Cristina Meira Zaparoli ◽  
Nelson Vicente Lovatto Gasparetto
Keyword(s):  
Iron Oxide ◽  
Surface Morphology ◽  
Iron Oxides ◽  
Morphological Analysis ◽  
Chemical Change ◽  
Subtropical Climate ◽  
Plasma Infusion ◽  
The City ◽  
Quartz Grains ◽  
Bt Horizon

This research aimed to compare the surface morphology of quartz grains of the E and Bt horizons of an Ultisol of the Aratu stream basin, in the city of Floraí, Paraná. The Ultisol is derived from sandstones of the Caiuá Formation and it is subjected to mesothermal humid subtropical climate. The materials from the E horizon showed abundant porosity compared to the Bt horizon ones, due to the filling of pores by coating of clay and iron oxides. On the surface of the quartz grains of the E horizon, several features were identified such as ";craters";, pyramidal microfeatures, gulfs of dissolution, elongated cavities, and silica reprecipitation, resulting from the chemical change, and fragmented grains resulting from a phenomenon called ";plasma infusion."; In the Bt horizon, nearly all the detrital grains were surrounded by clay and iron oxide. The detrital grains of the Bt horizon were better preserved, showing little corrosion features and rare fragmented grains, compared to the E horizon. These analyzes showed that the water flow accounts for the superficial alteration of detrital quartz grains when they are under the influence of humid subtropical climate.  R E S U M OA pesquisa teve como objetivo comparar a morfologia superficial de grãos de quartzo dos horizontes E e Bt de um Argissolo da bacia do córrego Aratu, no município de Floraí, PR. O Argissolo é derivado de arenitos da Formação Caiuá e submetido a clima subtropical úmido mesotérmico. Os materiais do horizonte E apresentam porosidade abundante quando comparados com os do horizonte Bt, em razão do preenchimento dos poros por revestimentos de argila e óxidos de ferro. Foram identificadas na superfície dos grãos de quartzo do horizonte E várias feições tipo “crateras”, microfeições piramidais, golfos de dissolução, cavidades alongadas, reprecipitação de sílica, oriundas da alteração química, e grãos fragmentados devido ao fenômeno denominado “plasma infusion”. No horizonte Bt, praticamente todos os grãos detritais estão envolvidos por argila e óxidos de ferro. Os grãos detritais do horizonte Bt estão mais preservados, exibindo poucas feições de corrosão e raros grãos fragmentados, se comparados com os do horizonte E. Essas análises demonstraram que o fluxo hídrico é o responsável pela alteração superficial dos grãos detritais de quartzo quando sob a influência de clima subtropical úmido. Palavras-chave: Argissolo, morfologia de grãos de quartzo, alteração geoquímica, fluxo hídrico 

scholarly journals Iron Oxide Contents in Relation to the Colour of Asnawa Soils

2017 ◽  
Vol 1 (1) ◽  
pp. 89-94
Author(s):  
Sherwan Kafoor
Keyword(s):  
Iron Oxide ◽  
Soil Properties ◽  
Iron Oxides ◽  
Soil Samples ◽  
Visual Methods ◽  
Colour Intensity ◽  
Fe Oxide ◽  
Fe Oxides ◽  
New Formula

Asnawa soils contain high amounts of iron oxides. These minerals apply much influence on different soil properties, of which the most observable is colour. The objective of this study was to conclude if colour of soils measured by visual methods can be parameterized to quantify soil Fe oxides. The examined area was divided to three zones (zone A, zone B and zone C) according to their colour intensity. Forty soil samples were examined for their colour and iron oxide contents. Their colour were ranged between 5YR (H) 2.5 (V/C) to 5YR (H) 5/8 (V/C). The average values of free Fe oxide in the soils of the three zones were 52.1%, 36.8% and 15.9% respectively. A new formula was derived to measure colour intensity. A highly significant correlation was found between colour intensity and concentrations of Fe oxides in the examined soils.

Facilitated Heterogeneous Photodegradation of Dissolved Organic Matter by Particulate Iron

2004 ◽  
Vol 1 (3) ◽  
pp. 197 ◽  
Author(s):  
Julia A. Howitt ◽  
Darren S. Baldwin ◽  
Gavin N. Rees ◽  
Barry T. Hart
Keyword(s):  
Organic Matter ◽  
Iron Oxide ◽  
Dissolved Organic Matter ◽  
Iron Oxides ◽  
Aquatic Ecosystems ◽  
Photochemical Reactions ◽  
Freshwater Systems ◽  
Particulate Iron ◽  
Presence And Absence ◽  
Australian Freshwater

Environmental Context. Iron oxides, as suspended minerals or as a colloidal phase, are common in Australian freshwater systems. Freshwater systems are also loaded with carbon-based substances, ‘dissolved organic matter’, but not all is biologically available as food to freshwater organisms. However, photochemical interactions between these iron oxides and dissolved organic matter provide a mechanism for biologically resistant carbon to re-enter the food web. Suspended iron oxides thus need to be considered in carbon cycles in aquatic ecosystems. Abstract. The photochemical degradation of dissolved organic matter (DOM) derived from the leaves of River Red Gum (Eucalyptus camaldulensis) was examined, with a particular focus on the photochemical generation of CO2, consumption of O2, and the effect of particulate iron minerals on these photochemical reactions. Solutions of leaf leachate were irradiated with ultraviolet and visible light in the presence and absence of amorphous iron oxides. Addition of fresh iron oxide was found to increase the rate of photodegradation of the organic matter by up to an order of magnitude compared to the reactions without added iron oxide. The ratio of CO2 produced to O2 consumed was ~1:1 in both the presence and absence of iron oxyhydroxide. The reactivity of the iron oxides was dependent on the preparation method and decreased with increased storage time. These results suggest that photochemical reactions on particle surfaces should be considered when examining carbon transformation in aquatic ecosystems, especially at sites with potential for the production of iron oxyhydroxides.

Magnetic Properties of Ferrous Ferric Oxide Confined in Porous Silicon

2010 ◽  
Vol 663-665 ◽  
pp. 1142-1145
Author(s):  
Yuan Ming Huang ◽  
Bao Gai Zhai ◽  
Qing Lan Ma ◽  
Ming Meng
Keyword(s):  
Electron Microscopy ◽  
Magnetic Properties ◽  
Iron Oxide ◽  
Porous Silicon ◽  
Ferrous Iron ◽  
Silicon Film ◽  
X Ray ◽  
Loop Measurement ◽  
Scanning Electron

During the chemical synthesis nanometer-sized particles of ferrous iron oxide were in situ infiltrated into the mesopores in a porous silicon film. The microstructures of porous silicon and the magnetic properties of the nanometer-sized particles of the ferrous iron oxide were characterized with scanning electron microscopy, X-ray diffractometry, and the hysteresis loop measurement, respectively. Our results have demonstrated that the magnetic properties of the nanometer-sized Fe3O4 particles can be dramatically modified when they are confined into the mesopores of the porous silicon film.

Microstructure, Stiffness and Corrosion of Bare and Phosphated Specimens Made by Sintering of Structured Iron-Iron Oxide Spheres

2020 ◽  
Vol 405 ◽  
pp. 411-416
Author(s):  
Miriam Kupková ◽  
Martin Kupka ◽  
Renáta Oriňáková ◽  
Radka Gorejová
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Metallic Iron ◽  
Galvanic Corrosion ◽  
Iron Phosphate ◽  
Reduction Reaction ◽  
Diffusion Control ◽  
Iron Oxide Particles ◽  
Flow Through ◽  
Iron Iron

Granulated iron oxide particles were incompletely reduced to structured particles comprised metallic iron and residual iron oxides. Structured particles were pressed into prismatic compacts and sintered. Some of sintered specimens were subsequently phosphatized and calcined. Specimens with an iron phosphate coating were found stiffer than specimens without coating. In Hanks' solution, a galvanic corrosion was induced by more noble iron oxides coupled to a less noble metallic iron. This could explain higher corrosion potentials and higher rates of iron dissolution in comparison with a pure iron. The coating of specimens with iron phosphates shifted corrosion potentials towards more negative values and slowed down the dissolution of iron. This was most likely caused by a reduction in oxygen flow through the coating to iron-oxide cathodes, which has enhanced the influence of diffusion control on the kinetics of reduction reaction.

The geologic history of seawater oxygen isotopes from marine iron oxides

Science ◽  
2019 ◽  
Vol 365 (6452) ◽  
pp. 469-473 ◽  
Author(s):  
Nir Galili ◽  
Aldo Shemesh ◽  
Ruth Yam ◽  
Irena Brailovsky ◽  
Michal Sela-Adler ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Oxygen Isotope ◽  
Iron Oxides ◽  
Isotope Composition ◽  
Geologic History ◽  
Temperature Dependent ◽  
Oxygen Isotope Fractionation ◽  
History Of ◽  
Sediment Cover

The oxygen isotope composition (δ18O) of marine sedimentary rocks has increased by 10 to 15 per mil since Archean time. Interpretation of this trend is hindered by the dual control of temperature and fluid δ18O on the rocks’ isotopic composition. A new δ18O record in marine iron oxides covering the past ~2000 million years shows a similar secular rise. Iron oxide precipitation experiments reveal a weakly temperature-dependent iron oxide–water oxygen isotope fractionation, suggesting that increasing seawater δ18O over time was the primary cause of the long-term rise in δ18O values of marine precipitates. The18O enrichment may have been driven by an increase in terrestrial sediment cover, a change in the proportion of high- and low-temperature crustal alteration, or a combination of these and other factors.

Iron Oxide (U–Th)/He Thermochronology: New Perspectives on Faults, Fluids, and Heat

Elements ◽  
2020 ◽  
Vol 16 (5) ◽  
pp. 319-324
Author(s):  
Emily H. G. Cooperdock ◽  
Alexis K. Ault
Keyword(s):  
Fluid Flow ◽  
Iron Oxide ◽  
Heat Exchange ◽  
Iron Oxides ◽  
Fault Zone ◽  
Frictional Heating ◽  
Fault Zones ◽  
Chemical Behavior ◽  
Rock Interaction ◽  
Dynamic Motion

Fault zones record the dynamic motion of Earth’s crust and are sites of heat exchange, fluid–rock interaction, and mineralization. Episodic or long-lived fluid flow, frictional heating, and/or deformation can induce open-system chemical behavior and make dating fault zone processes challenging. Iron oxides are common in a variety of geologic settings, including faults and fractures, and can grow at surface-to magmatic temperatures. Recently, iron oxide (U–Th)/He thermochronology, coupled with microtextural and trace element analyses, has enabled new avenues of research into the timing and nature of fluid–rock interactions and deformation. These constraints are important for understanding fault zone evolution in space and time.

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