Characterisation of oxygen plasma-modified mica surfaces using XPS and AFM

Liu, Zhihui; Brown, N. M. D.; McKinley, A

doi:10.1016/s0169-4332(96)00683-6

Cited by 34 publications

(27 citation statements)

References 18 publications

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“…This serves as evidence that the preparation of kerogen did not isotopically fractionate N org . High temperature and long duration of plasma ashing can change the surface topography and the chemical composition of residual mica (Liu et al, 1997), possibly causing nitrogen isotopic fractionation due to partial loss of ammonia. However, we found that δ 15 N ammonium values of isolated ammonium were similar to δ 15 N values that were calculated by isotopic mass-balance as the difference between measured N total in original rock and measured N org in kerogen.…”

Section: Elemental Isotopic and Thermal Analysesmentioning

confidence: 99%

Organic nitrogen chemistry during low-grade metamorphism

Boudou

Schimmelmann

Ader

et al. 2008

Geochimica et Cosmochimica Acta

136

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-Most of the organic nitrogen (N org ) on Earth is disseminated in crustal sediments and rocks in the form of fossil nitrogen-containing organic matter. The chemical speciation of fossil N org within the overall molecular structure of organic matter changes with time and heating during burial. Progressive thermal evolution of organic matter involves phases of enhanced elimination of N org and ultimately produces graphite containing only traces of nitrogen. Long-term chemical and thermal instability makes the chemical speciation of N org a valuable tracer to constrain the history of sub-surface metamorphism and to shed light on the subsurface biogeochemical nitrogen cycle and its participating organic and inorganic nitrogen pools. This study documents the evolutionary path of N org speciation, transformation and elimination before and during metamorphism and advocates the use of XRay Photoelectron Spectroscopy (XPS) to monitor changes in N org speciation as a diagnostic tool for organic metamorphism. Our multidisciplinary evidence from XPS, stable isotopes, traditional quantitative coal analyses, and other analytical approaches shows that at the metamorphic onset N org is dominantly present as pyrrolic and pyridinic nitrogen. The relative abundance of nitrogen substituting for carbon in condensed, partially aromatic systems (where N is covalently bonded to three C atoms) increases exponentially with increasing metamorphic grade, at the expense of pyridinic and pyrrolic nitrogen. At the same time, much N org is eliminated without significant nitrogen isotope fractionation. The apparent absence of Rayleigh-type nitrogen isotopic fractionation suggests that direct thermal loss of nitrogen from an organic matrix does not serve as a major pathway for N org elimination. Instead, we propose that hot H, O-containing fluids or some of their components gradually penetrate into the carbonaceous matrix and eliminate N org along a progressing reaction front, without causing nitrogen isotope fractionation in the residual N org in the unreacted core of the carbonaceous matrix. Before the reaction front can reach the core, an increasing part of core N org chemically stabilizes in the form of nitrogen atoms substituting for carbon in condensed, partially aromatic systems forming graphite-like structural domains with delocalized π-electron systems (nitrogen atoms substituting for "graphitic" carbon in natural metamorphic organic matter). Thus, this nitrogen species with a conservative isotopic composition is the dominant form of residual nitrogen at higher metamorphic grade.

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Section: Elemental Isotopic and Thermal Analysesmentioning

confidence: 99%

Organic nitrogen chemistry during low-grade metamorphism

Boudou

Schimmelmann

Ader

et al. 2008

Geochimica et Cosmochimica Acta

136

View full text Add to dashboard Cite

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“…The Al 2p XPS peak centered at 74.5 eV assigned to mica [28] had almost no change in the DSAD process (curve (a) and curve (b) in Figure 8). It is suggested that the mica structure has not been destroyed.…”

Section: Analysis Of Leaching Residue and Leachatementioning

confidence: 99%

“…The generation of iron-sulphate compound and the dissolution of hematite in the first-stage PAL process indicated that the formation of iron-sulphate compound by Fe hydrolyzation could be initiated more easily than that of hematite under these pressure acid leaching conditions, because the strong binding anions like SO 4 2´c ould favor the formation of this iron-sulphate compound [27]. The Al 2p XPS peak centered at 74.5 eV assigned to mica [28] had almost no change in the DSAD process (curve (a) and curve (b) in Figure 8). It is suggested that the mica structure has not been destroyed.…”

Section: Thermodynamics Analysismentioning

confidence: 99%

Selective Leaching of Vanadium from Roasted Stone Coal by Dilute Sulfuric Acid Dephosphorization-Two-Stage Pressure Acid Leaching

et al. 2016

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A novel staged leaching process has been reported in this paper to selectively extract vanadium from roasted stone coal and the mechanisms have been clarified. Results showed that the leaching efficiency of V, Al, P and Fe was 80.46%, 12.24%, 0.67% and 3.12%, respectively, under the optimum dilute sulfuric acid dephosphorization (DSAD)-two-stage pressure acid leaching (PAL) conditions. The efficient separation of V from Fe, Al and P was realized. As apatite could be leached more easily than mica, the apatite could completely react with sulfuric acid, while the mica had almost no change in the DSAD process, which was the key aspect in realizing the effective separation of V from P. Similarly, the hydrolyzation of Fe and Al could be initiated more easily than that of V by decreasing the residual acid of leachate. The alunite and iron-sulphate compound generated in the first-stage PAL process resulted in the effective separation of V from Fe and Al.

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“…As a consequence, 30 chondrogenic differentiation of human mesenchymal stem cells was observed 12, 13 . Analogously, physiochemical adsorption of 40 surface-active polymers at solid/liquid interface can produce polymeric self-assembled monolayers (PSAMs) that offer a variety of unique functionalities as well as improved surface stability and processability [18][19][20][21] . Self-assembled materials mimicking ECM have emerged as promising bioengineering tools 35 as they can provide precisely tailored, chemically well-defined substrates.…”

Section: Introductionmentioning

confidence: 99%

“…Structure of SAMs and PSAMs strongly depends on chemical properties of the solid surface, its morphology, adsorption 60 mechanism and nature of forces operating at the boundary 22,23 . However, the process is difficult to control and sensitive to the 75 applied reaction conditions [36][37][38][39][40] . Muscovite is very susceptible to cleavage along the plane located in the potassium 65 layer.…”

Section: Introductionmentioning

confidence: 99%

Supramolecular self-assembly of linear oligosilsesquioxanes on mica – AFM surface imaging and hydrophilicity studies

et al. 2015

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Linear oligomeric [2-(carboxymethylthio)ethylsilsesquioxanes] (LPSQ-COOH) adsorb spontaneously on muscovite mica and form smooth, well-ordered lamellar structures at the liquid-solid interface. Side carboxylic groups, having donor-acceptor character with regard to hydrogen bonds, are engaged both in multipoint molecule-to-substrate interactions and intermolecular cross-linking. The unique arrangement of silsesquioxane macromolecules, with COOH groups situated at the interface with air, produces highly hydrophilic surfaces of good thermal and solvolytic stability. Supramolecular assemblies of LPSQ-COOH were studied using atomic force microscopy (AFM), angle-resolved X-ray photoelectron spectroscopy (ARXPS) and attenuated total reflectance (ATR) FTIR spectroscopy. Comparative height profile analysis combined with ATR-FTIR studies of the spectral regions characteristic of carboxylic groups and C1s core level envelope by XPS confirmed specific interactions between LPSQ-COOH and mica.

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Characterisation of oxygen plasma-modified mica surfaces using XPS and AFM

Cited by 34 publications

References 18 publications

Organic nitrogen chemistry during low-grade metamorphism

Organic nitrogen chemistry during low-grade metamorphism

Selective Leaching of Vanadium from Roasted Stone Coal by Dilute Sulfuric Acid Dephosphorization-Two-Stage Pressure Acid Leaching

Supramolecular self-assembly of linear oligosilsesquioxanes on mica – AFM surface imaging and hydrophilicity studies

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