Coupled Kinetics Model for Microbially Mediated Arsenic Reduction and Adsorption/Desorption on Iron Oxides: Role of Arsenic Desorption Induced by Microbes

2019 ◽  
Vol 53 (15) ◽  
pp. 8892-8902 ◽  
Author(s):  
Jingyi Lin ◽  
Shiwen Hu ◽  
Tongxu Liu ◽  
Fangbai Li ◽  
Lanfang Peng ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Kinetics Model ◽  
Arsenic Reduction ◽  
Adsorption Desorption

scholarly journals Phosphate removal from water by naturally occurring shale, sandstone, and laterite: The role of iron oxides and of soluble species

2019 ◽  
Vol 351 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Dan Eude Kpannieu ◽  
Martine Mallet ◽  
Lacina Coulibaly ◽  
Mustapha Abdelmoula ◽  
Christian Ruby
Keyword(s):  
Iron Oxides ◽  
Phosphate Removal ◽  
Naturally Occurring ◽  
Soluble Species

Pentachlorophenol dechlorination with zero valent iron: a Raman and GCMS study of the complex role of surficial iron oxides

2018 ◽  
Vol 25 (18) ◽  
pp. 17797-17806 ◽  
Author(s):  
Buddhika Gunawardana ◽  
Peter J. Swedlund ◽  
Naresh Singhal ◽  
Michel K. Nieuwoudt
Keyword(s):  
Iron Oxides ◽  
Zero Valent Iron

Facilitating role of Pd for hydrogen, oxygen and water adsorption/desorption processes from bulk CeO2 and CeO2/γ-Al2O3

2019 ◽  
Vol 323 ◽  
pp. 141-147 ◽  
Author(s):  
Deniz Kaya ◽  
Dheerendra Singh ◽  
Serkan Kincal ◽  
Deniz Uner
Keyword(s):  
Water Adsorption ◽  
Adsorption Desorption

Carbonised polyaniline and polypyrrole: towards advanced nitrogen-containing carbon materials

2013 ◽  
Vol 67 (8) ◽  
Author(s):  
Gordana Ćirić-Marjanović ◽  
Igor Pašti ◽  
Nemanja Gavrilov ◽  
Aleksandra Janošević ◽  
Slavko Mentus
Keyword(s):  
Electrical Conductivity ◽  
Carbon Materials ◽  
Modern Technology ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Elemental Analyses ◽  
Adsorption Desorption

AbstractPolyaniline (PANI) and polypyrrole (PPY) undergo carbonisation in an inert/reduction atmosphere and vacuum, yielding different nitrogen-containing carbon materials. This contribution reviews various procedures for the carbonisation of PANI and PPY precursors, and the characteristics of obtained carbonised PANI (C-PANI) and carbonised PPY (C-PPY). Special attention is paid to the role of synthetic procedures in tailoring the formation of C-PANI and C-PPY nanostructures and nanocomposites. The review considers the importance of scanning and transmission electron microscopies, XPS, FTIR, Raman, NMR, and EPR spectroscopies, electrical conductivity and adsorption/desorption measurements, XRD, and elemental analyses in the characterisation of C-PANIs and C-PPYs. The application of C-PANI and C-PPY in various fields of modern technology is also reviewed.

Magnetic characterization of ghost rocks from the Sterkfontein cave (South Africa): are iron oxides linked to biological activity?

2020 ◽  
Author(s):  
Aude Isambert ◽  
Maud Watkinson ◽  
Céline Pisapia ◽  
Emmanuelle Gérard ◽  
Bénédicte Menez ◽  
...  
Keyword(s):  
South Africa ◽  
Iron Oxides ◽  
Magnetic Measurements ◽  
Bacterial Biofilm ◽  
High Porosity ◽  
Secondary Phases ◽  
Biological Origin ◽  
Potential Habitat ◽  
Cave System

<p>The Sterkfontein caves system in the Cradle of Humankind (South Africa) is a karstic environment resulting from a ghost-rock karstification process that developed in the Malmani dolomite formation presenting interlayered more resistant chert layers (Bruxelles, 2017). This process of karstification occurs under low hydrodynamic conditions leaving in place a residual highly porous altered rock, which preserves the structure of the initial bedrock, and which is called “ghost rock”. Due to its high porosity and in the presence of water, ghost-rocks can represent a potential habitat for microorganisms, ubiquitous on and in Earth, with metabolisms mainly relying on dissolution or precipitation processes of minerals. Thus some secondary mineralizations of manganese and iron oxides, found associated to microorganisms in cave systems, could have a biological origin (Banerjee and Joshi, 2012). To better characterize the alteration phases and understand the process of karstification and the potential role of microorganisms and biofilms, samples including dolomitic bedrock, cherts and ghost-rocks were collected at the Sterkfontein cave system. We report here magnetic properties of powdered samples (low-field susceptibility, hysteresis parameters, saturation magnetization and MPMS measurements). In parallel to these magnetic measurements, XRD analyses, FTIR spectroscopic analyses and microscopic observations (SEM) have been realized in order to better characterize the mineralogy of bedrock and secondary phases and to better constrain the alteration processes. We observe that the ghost-rock is mostly composed of quartz and oxides. The magnetic phases detected are mainly hematite and goethite, precipitated on the quartz grain boundaries. These first observations could be explained by a total dissolution of the main bedrock (dolomite) and a partial chemical alteration and mechanical erosion of cherts. To go further, an additional microbial ecology study in the cave system is needed to better constrain the role of microorganisms in the precipitation of oxides detected.</p><p> </p><p>Banerjee, S., Joshi, S.R., 2013. Insights into Cave Architecture and the Role of Bacterial Biofilm. PNAS, India Section B: Biological Sciences 83, 277–290.</p><p>Bruxelles L., 2017. Des fantômes et des hommes. Le rôle de la fantômisation dans la formation des karsts à homininés d’Afrique du Sud. Karstologia 69, 1–8.</p>

ON THE ROLE OF IRON OXIDES IN THE ELECTROCHEMICAL BEHAVIOUR OF STEEL EMBEDDED IN CONCRETE

2005 ◽  
Vol 23 (2-3) ◽  
pp. 195-216 ◽  
Author(s):  
X.R. Nóvoa, ◽  
M.C. Pérez,
Keyword(s):  
Iron Oxides ◽  
Electrochemical Behaviour

A Mathematical Model Forecasting HF Adsorption onto Cu-Coated Wafers as a Function of the Airborne Concentration and Moisture

2016 ◽  
Vol 255 ◽  
pp. 323-328
Author(s):  
Fernando Herrán ◽  
Hervé Fontaine ◽  
Paola González-Aguirre ◽  
Carlos Beitia ◽  
Jim Ohlsen ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Surface Concentration ◽  
Threshold Concentration ◽  
Sorption Behavior ◽  
Yield Losses ◽  
Airborne Concentration ◽  
Adsorption Desorption

In order to better understand and model the whole sorption behavior of the HF when in contact with a Cu surface inside a FOUP and thus control the related yield losses, Cu-coated wafers have been exposed to varying HF (ppbv) and H2O (% RH) airborne concentrations. These experiments have yielded a HF-Cu sorption empirical-mathematical model that may be used as an industrial tool for queue-time or fluoride surface concentration predictions. Besides, the formation of CuF2 only in case of corrosion is evidenced by the XPS measurements whereas the key role of the H2O is further confirmed by the desorption experiments. The H2O retained by the surface is actually responsible for promoting the HF adsorption/desorption onto/from Cu and enables a HF threshold concentration that separates the two well differenced uptake regimes; adsorption and corrosion.

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