Imaging the heterogeneity of mineral surface reactivity using Ag(I) and synchrotron X-ray microscopy

2003 ◽  
Vol 30 (9) ◽  
pp. 559-569 ◽  
Author(s):  
J. E. Amonette ◽  
S. M. Heald ◽  
C. K. Russell
Keyword(s):  
Surface Reactivity ◽  
Mineral Surface ◽  
X Ray

Minerals, metals and molecules: ore and environmental mineralogy in the new millennium

2002 ◽  
Vol 66 (5) ◽  
pp. 653-676 ◽  
Author(s):  
D. J. Vaughan ◽  
R. A. D. Pattrick ◽  
R. A. Wogelius
Keyword(s):  
Scanning Probe Microscopy ◽  
Mineral Exploration ◽  
Bacterial Colonization ◽  
Surface Reactivity ◽  
Scanning Probe ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Exploration And Exploitation ◽  
X Ray ◽  
Molecular Scale

AbstractAspects of the (bio)geochemical cycling of metals (including Fe, Cu, Pb, Zn, Hg, As, Sb, U, Tc, Np) at or near the Earth's surface are discussed with reference to the recent work of the authors. Key stages of the breakdown of metalliferous minerals, transport of metals as solution complexes or colloidal precipitates, and interaction of metals in solution with the surfaces of minerals are considered. Emphasis is on molecular-scale observations using techniques such as scanning probe microscopy, photoelectron and (synchrotron) X-ray spectroscopies. The importance of the biological/mineralogical interface is also emphasized with reference to the bacterial colonization of mineral surfaces and formation of biofilms, and their influence on mineral surface reactivity and flow of fluids through rocks and sediments. Also noted is the importance of relating molecular and micro-scale observations to macroscopic phenomena. Molecular-scale understanding is central to attempts to model many processes of relevance in mineral exploration and exploitation, and in the containment of hazardous wastes and remediation of polluted areas. Mineralogists have a central role to play in the relevant environmental sciences and technologies.

Microorganisms in Bioflotation and Bioflocculation: Potential Application and Research Needs

2009 ◽  
Vol 71-73 ◽  
pp. 319-328 ◽  
Author(s):  
K. Hanumantha Rao ◽  
Annamaria Vilinska ◽  
I.V. Chernyshova
Keyword(s):  
Energy Charge ◽  
Surface Reactivity ◽  
Basic Knowledge ◽  
Primary Data ◽  
Great Promise ◽  
Mineral Surface ◽  
Processing Technologies ◽  
Ore Processing ◽  
Charge Potential ◽  
Mineral Beneficiation

Conventionally, physico-chemical methods are used in mineral processing for recovering value minerals from ores. The ageing of ore processing tailings and waste rocks, and mining tailings contamination by chemical reagents constitute a major threat to the environment. It is imperative to develop novel economically more efficient and environmentally benign methods of flotation and waste processing, exploiting the intriguing and exciting ability of bacteria to selectively modify the surface properties of solids. Microorganisms have not only facilitate hydrometallurgical leaching operations but have also show a great promise in mineral beneficiation processes such as flotation and flocculation. Several laboratory investigations revealed that microorganisms could function similar to traditional reagents. Microorganisms have a tremendous influence on their environment through the transfer of energy, charge, and materials across a complex biotic mineral-solution interface. The bio-modification of mineral surfaces involves the complex action of microorganism on the mineral surface. The manner, in which bacteria affect the surface reactivity and the mechanism of bacteria adsorption, is still unknown and accumulation of the primary data in this area is only starting. The bio-flotation and bio-flocculation processes concern the mineral response to the bacterium presence, which is essentially interplay between microorganism and the physicochemical properties of the mineral surface, such as the atomic and electronic structure, the net charge/potential, acid-base properties, and wettability of the surface. There is an urgent need for developing basic knowledge that would underpin biotechnological innovations in the natural resource (re)processing technologies that deliver competitive solutions.

scholarly journals Organomineral nanocomposite carbon burial during Oceanic Anoxic Event 2

2014 ◽  
Vol 11 (5) ◽  
pp. 6815-6844
Author(s):  
S. C. Löhr ◽  
M. J. Kennedy
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
X Ray ◽  
Oceanic Anoxic Event ◽  
Carbon Burial ◽  
Anoxic Events ◽  
Mineral Surface Area

Abstract. Organic carbon (OC) enrichment in sediments deposited during Oceanic Anoxic Events (OAEs) is commonly attributed to elevated productivity and marine anoxia. We find that OC enrichment in the late Cenomanian aged OAE2 at Demerara Rise was controlled by co-occurrence of anoxic bottom-water, sufficient productivity to saturate available mineral surfaces and variable deposition of high surface area detrital smectite clay. Redox indicators show consistently oxygen-depleted conditions, while a strong correlation between OC concentration and sediment mineral surface area (R2=0.92) occurs across a range of TOC values from 9–33%. X-ray diffraction data indicates intercalation of OC in smectite interlayers while electron, synchrotron infrared and X-ray microscopy show an intimate association between clay minerals and OC, consistent with preservation of OC as organomineral nanocomposites and aggregates rather than discrete, μm-scale pelagic detritus. Since the consistent ratio between TOC and mineral surface area suggests that excess OC relative to surface area is lost, we propose that it is the varying supply of smectite that best explains variable organic enrichment against a backdrop of continuous anoxia, which is conducive to generally high TOC during OAE2 at Demerara Rise. Smectitic clays are unique in their ability to form stable organomineral nanocomposites and aggregates that preserve organic matter, and are common weathering products of continental volcanic deposits. An increased flux of smectite coinciding with high carbon burial is consistent with evidence for widespread volcanism during OAE2, so that organomineral carbon burial may represent a potential feedback to volcanic degassing of CO2.

Mineral surface reactivity and mass transfer in environmental mineralogy

2007 ◽  
Vol 19 (3) ◽  
pp. 297-307 ◽  
Author(s):  
Roy A. Wogelius ◽  
Peter M. Morris ◽  
Michael A. Kertesz ◽  
Emmanuelle Chardon ◽  
Alexander I.R. Stark ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Surface Reactivity ◽  
Mineral Surface

scholarly journals The Structure of Actinide Ions Exchanged into Native and Modified Zeolites and Clays

1999 ◽  
Vol 590 ◽  
Author(s):  
Stephen R. Wasserman ◽  
L. Soderholm ◽  
Daniel M. Giaquinta
Keyword(s):  
Pore Size ◽  
Organic Films ◽  
Mineral Surface ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Chemical Fate ◽  
Smectite Clays ◽  
Modified Zeolites ◽  
X Ray Absorption ◽  
Actinide Ions

ABSTRACTx-ray absorption spectroscopy (XAS) has been used to investigate the structure and valence of thorium (Th4+) and uranyl () cations exchanged into two classes of microporous aluminosilicate minerals: zeolites and smectite clays. XAS is also employed to examine the fate of the exchanged cations after modification of the mineral surface using self-assembled organic films and/or exposure to hydrothermal conditions. These treatments serve as models for the forces that ultimately determine the chemical fate of the actinide cations in the environment. The speciation of the cations depends on the pore size of the aluminosilicate, which is fixed for the zeolites and variable for the smectites.

scholarly journals Ultraviolet Irradiation on a Pyrite Surface Improves Triglycine Adsorption

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 50 ◽  
Author(s):  
Santos Galvez-Martinez ◽  
Eva Mateo-Marti
Keyword(s):  
Functional Group ◽  
Chemical Species ◽  
Photoemission Spectroscopy ◽  
Molecular Adsorption ◽  
Surface Chemical ◽  
Pyrite Surface ◽  
Mineral Surface ◽  
Chemical Changes ◽  
X Ray ◽  
Highly Sensitive

We characterized the adsorption of triglycine molecules on a pyrite surface under several simulated environmental conditions by X-ray photoemission spectroscopy. The triglycine molecular adsorption on a pyrite surface under vacuum conditions (absence of oxygen) shows the presence of two different states for the amine functional group (NH2 and NH3+), therefore two chemical species (anionic and zwitterionic). On the other hand, molecular adsorption from a solution discriminates the NH2 as a unique molecular adsorption form, however, the amount adsorbed in this case is higher than under vacuum conditions. Furthermore, molecular adsorption on the mineral surface is even favored if the pyrite surface has been irradiated before the molecular adsorption occurs. Pyrite surface chemistry is highly sensitive to the chemical changes induced by UV irradiation, as XPS analysis shows the presence of Fe2O3 and Fe2SO4—like environments on the surface. Surface chemical changes induced by UV help to increase the probability of adsorption of molecular species and their subsequent concentration on the pyrite surface.

Sign in / Sign up

Export Citation Format

Share Document