A software package for the analysis of X-ray absorption spectroscopy (XAS) data is presented. This package is based on the IFEFFIT library of numerical and XAS algorithms and is written in the Perl programming language using the Perl/Tk graphics toolkit. The programs described here are: (i) ATHENA, a program for XAS data processing, (ii) ARTEMIS, a program for EXAFS data analysis using theoretical standards from FEFF and (iii) HEPHAESTUS, a collection of beamline utilities based on tables of atomic absorption data. These programs enable high-quality data analysis that is accessible to novices while still powerful enough to meet the demands of an expert practitioner. The programs run on all major computer platforms and are freely available under the terms of a free software license.

http://cars9.uchicago.edu/xafs_school/Material/Articles/Horae%20JSR2005.pdf

ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT.

Application of biosorption for the removal of organic pollutants: a review

The article focuses on adsorption of heavy metal ions on soils and soils constituents such as clay minerals, metal (hydr)oxides, and soil organic matter. Empirical and mechanistic model approaches for heavy metal adsorption and parameter determination in such models have been reviewed. Sorption mechanisms in soils, the influence of surface functional groups and surface complexation as well as parameters influencing adsorption are discussed. The individual adsorption behavior of Cd, Cr, Pb, Cu, Mn, Zn and Co on soils and soil constituents is reviewed.

Adsorption of heavy metal ions on soils and soils constituents

Bacterial biosorbents and biosorption

Magmatic fluids, both vapour and hypersaline liquid, are a primary source of many components in hydrothermal ore deposits formed in volcanic arcs. These components, including metals and their ligands, become concentrated in magmas in various ways from various sources, including subducted oceanic crust. Leaching of rocks also contributes components to the hydrothermal fluid—a process enhanced where acid magmatic vapours are absorbed by deeply circulating meteoric waters. Advances in understanding the hydrothermal systems that formed these ore deposits have come from the study of their active equivalents, represented at the surface by hot springs and volcanic fumaroles.

The role of magmas in the formation of hydrothermal ore deposits

A chemical equilibrium model for metal adsorption onto bacterial surfaces

Cd adsorption onto bacterial surfaces: A universal adsorption edge?

X-ray absorption fine structure determination of pH-dependent U-bacterial cell wall interactions

Experimental studies, using cold-seal and extraction vessel techniques, were conducted on Fe, Pb, Zn, and Cu sulfide solubilities in chloride solutions at temperatures from 300 degrees to 700 degrees C and pressures from 0.5 to 2 kbars. The solutions were buffered in pH by a quartz monzonite and the pure potassium feldspar-muscovite-quartz assemblage and in f (sub S 2 ) - f (sub O 2 ) largely by the assemblage pyrite-pyrrhotite-magnetite.Solubilities increase with increasing temperature and total chloride, and decrease with increasing pressure. The rise in solubility is particularly steep between 300 degrees and 500 degrees C and between 1,000 and 500 bars. With increasing temperature at any given pressure, or with decreasing pressure at any given temperature, metal solubility eventually passes through a maximum due to increasing competition for chloride by the alkali, hydrogen, and base metal ions and because intersection with a two-fluid region eventually occurs. In that portion of the two-fluid region encountered in the study, metal solubilities in the brine were very high, but solubilities in the gas phase also were significant. In a system controlled by the potassium feldspar-muscovite-quartz buffer, 1-m total Cl (super -) , and the assemblage pyrite-pyrrhotite-magnetite-sphalerite-galena-chalcopyrite, solubilities in ppm at 1 kbar and 300 degrees , 400 degrees , and 500 degrees C were 237, 1,216, and 5,636, for Fe; 51, 613, and 3,105 for Pb; 36, 423, and 2,649 for Zn; and 11, 40, and 113 for Cu, respectively. At 400 degrees C, 0.5 and 2 kbars, the values were 2,627 and 500 for Fe; 1,262 and 194 for Pb; 983 and 120 for Zn; and 60 and 29 for Cu, respectively. All of the above were in the single-fluid region. Single-metal solubilities also were investigated to assess the influence of iron on the solubility of the other metals and to corroborate preliminary dissociation constants for the metal chloride complexes involved.The effect of increasing chloride concentration on solubility reflects primarily a shift to lower pH via the silicate buffer reactions. The effect of decreasing pressure reflects primarily the relative change in the dissociation constants of the chloride complexes involved. Increasing sulfur fugacity lowers solubility, but in systems controlled at relatively low values by an f (sub S 2 ) buffer or wall-rock sulfidation reactions, solutions of high metal content relative to reduced sulfur will tend to develop at high chloride concentrations.Similarity in behavior with respect to the temperature and pressure of Fe, Zn, and Pb sulfide solubilities points to similarity in chloride speciation, and the neutral species appear to be dominant in the high-temperature region. At 500 degrees C and 1 kbar, the log K D values for FeCl degrees 2 , PbCl degrees 2 , ZnCl degrees 2 , and CuCl degrees are, respectively, -8.76, -9.14, -10.86, and -6.22.

Jeremy B. Fein

Papers

A chemical equilibrium model for metal adsorption onto bacterial surfaces

Cd adsorption onto bacterial surfaces: A universal adsorption edge?

X-ray absorption fine structure determination of pH-dependent U-bacterial cell wall interactions

Hydrothermal ore-forming processes in the light of studies in rock-buffered systems; I, Iron-copper-zinc-lead sulfide solubility relations

Experimental study of the pH, ionic strength, and reversibility behavior of bacteria–mineral adsorption