Electrochemical Dissolution of Goethite by Abrasive Stripping Voltammetry

1995 ◽  
Vol 60 (6) ◽  
pp. 950-959 ◽  
Author(s):  
Tomáš Grygar ◽  
Jan Šubrt ◽  
Jaroslav Boháček

Abrasive stripping voltammetry was applied to the investigation of the reductive dissolution of some iron(III) oxides and hydroxy-oxides, particularly goethite (α-FeOOH), in acid media. The electrode reaction directly involves the solid phase, and the reaction pathway depends on the phase composition and particle shape. This can be used for a qualitative and quantitative characterization of goethite. The results of a quantitative analysis of a mixture of goethite (α-FeOOH) and lepidocrocite (γ-FeOOH) are compared with those of IR and Moessbauer spectroscopic examination. The effects of the particle appearance (shape, crystal intergrowth) on the results of the voltammetric and chronoamperometric measurements are discussed.

2021 ◽  
Vol 12 ◽  
pp. 117959722098382
Author(s):  
Farid Menaa ◽  
Yazdian Fatemeh ◽  
Sandeep K Vashist ◽  
Haroon Iqbal ◽  
Olga N Sharts ◽  
...  

Graphene, a relatively new two-dimensional (2D) nanomaterial, possesses unique structure (e.g. lighter, harder, and more flexible than steel) and tunable physicochemical (e.g. electronical, optical) properties with potentially wide eco-friendly and cost-effective usage in biosensing. Furthermore, graphene-related nanomaterials (e.g. graphene oxide, doped graphene, carbon nanotubes) have inculcated tremendous interest among scientists and industrials for the development of innovative biosensing platforms, such as arrays, sequencers and other nanooptical/biophotonic sensing systems (e.g. FET, FRET, CRET, GERS). Indeed, combinatorial functionalization approaches are constantly improving the overall properties of graphene, such as its sensitivity, stability, specificity, selectivity, and response for potential bioanalytical applications. These include real-time multiplex detection, tracking, qualitative, and quantitative characterization of molecules (i.e. analytes [H2O2, urea, nitrite, ATP or NADH]; ions [Hg2+, Pb2+, or Cu2+]; biomolecules (DNA, iRNA, peptides, proteins, vitamins or glucose; disease biomarkers such as genetic alterations in BRCA1, p53) and cells (cancer cells, stem cells, bacteria, or viruses). However, there is still a paucity of comparative reports that critically evaluate the relative toxicity of carbon nanoallotropes in humans. This manuscript comprehensively reviews the biosensing applications of graphene and its derivatives (i.e. GO and rGO). Prospects and challenges are also introduced.


2013 ◽  
Vol 17 (04) ◽  
pp. 252-258 ◽  
Author(s):  
Qinggang He ◽  
Xiao Cheng ◽  
Ying Wang ◽  
Ruimin Qiao ◽  
Wanli Yang ◽  
...  

The dicobalt complex [ Co2(L2) ] of a Schiff-base pyrrole macrocycle adopts a Pacman structure in solution and the solid state and shows much greater catalytic activity and selectivity for the four-electron oxygen reduction reaction (ORR) than the mononuclear cobalt phthalocyanine (CoPc) counterpart. Soft X-ray absorption spectroscopy (XAS) shows that the Co center in Co2(L2) is of the same valence as mononuclear CoPc . However, the former complex shows higher unoccupied Co 3d density which is believed to be beneficial for electron transfers. Furthermore, the XAS data suggests that the crystal fields for Co2(L2) and CoPc are different, and that an interaction remains between two Co atoms in Co2(L2) . DFT calculations imply that the sterically hindered, cofacial structure of the dicobalt complex is critical for the operation of the four-electron reaction pathway during the ORR.


Author(s):  
Santanu Layek ◽  
M.K. Pandit ◽  
Sanket Kumar ◽  
Arindam Das ◽  
Ana mika ◽  
...  

2019 ◽  
Vol 571 ◽  
pp. 40-48 ◽  
Author(s):  
Wooseok Kim ◽  
Jihye Kim ◽  
Seungkwan You ◽  
Jonghye Do ◽  
Yeonjoo Jang ◽  
...  

Autophagy ◽  
2013 ◽  
Vol 9 (5) ◽  
pp. 770-777 ◽  
Author(s):  
Ricarda A. Busse ◽  
Andreea Scacioc ◽  
Javier M. Hernandez ◽  
Roswitha Krick ◽  
Milena Stephan ◽  
...  

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