Unveiling the Structural Origins of Dynamic Diversity in Pd-Based Metallic Glasses.

The β-relaxation is one of the major dynamic behaviors in metallic glasses (MGs) and exhibits diverse features. Despite decades of efforts, the understanding of its structural origin and contribution to the overall dynamics of MG systems is still unclear. Here two palladium-based Pd─Cu─P and Pd─Ni─P MGs are reported with distinct different β-relaxation behaviors and reveal the structural origins for the difference using the advanced X-ray photon correlation spectroscopy and absorption fine structure techniques together with the first-principles calculations.

Chlorine levels and species in fine and size resolved atmospheric particles by X-ray absorption near-edge structure spectroscopy analysis in Beijing, China.

An understanding of the species of chlorine is crucial in the metropolis-Beijing, which is suffering serious haze pollution with high frequency. Particulate Matters (PMs) with five different sizes were collected in Beijing from July 2009 to March 2016, and characterized non-destructively by X-ray absorption near edge structure spectroscopy. PM, PM and PM contributed for the major PMs mass in spring and summer, PM and PM contributed for the major PMs mass in autumn and winter.

[X-ray absorption spectroscopic evidence for the formation of Pb(II) inner-sphere adsorption complexes and precipitates at the alkaline soil-water interface].

Adsorption mechanisms of Pb on soil with high CaCO3 content were investigated by combined batch sorption and X-ray absorption fine structure (XAFS). Date from the batch equilibrium studies showed that Pb sorption was nonlinear and was well fitted to Langmiur isotherm. The XAFS data indicated that Pb could be adsorbed via the inner-sphere complex, the precipitation of calcium carbonate containing Pb (PbCaCO3), and outer-sphere Pb sorption complex.

[X-ray absorption fine structure (XAFS) study of the effects of pH on Pb(II) sorption by soil].

Combined batch sorption and in situ X-ray absorption fine structure (XAFS) provide direct assessment of the mechanisms for Pb(II) sorption at the soil-water interface under different pH conditions. The XAFS data indicated that the innersphere Pb sorption complex with ionic character (Pb4 (OH)4(4+)) dominated the Pb surface speciation, and the outer-sphere Pb sorption complex and the precipitation of calcium carbonate containing Pb(PbCaCO3) were also involved in the adsorption samples. Coordination number and radial distance of the first-shell Pb-O decreased from 0.

Difference of toxicity and accumulation of methylated and inorganic arsenic in arsenic-hyperaccumulating and -hypertolerant plants.

The arsenic (As) hyperaccumulators, Pteris vittata and Pteris cretica and an As-tolerant plant Boehmeria nivea, were selected to compare the toxicity, uptake, and transportation of inorganic arsenate (As(V)) and its methylated counterpart dimethylarsinic acid (DMA). The XANES method was used to elucidate the effect of As species transformation on As toxicity and accumulation characteristics. Significantly higher toxicity and lower accumulation of DMAthan inorganic As(V) was shown in the As hyperaccumulators and the As-tolerant plant.

Arsenic transformation and volatilization during incineration of the hyperaccumulator Pteris vittata L.

Safe incineration of harvested hyperaccumulators containing high content of heavy metals to avoid secondary environmental pollution is a problem for popularizing phytoremediation technology. The As volatilization behavior and its mechanism during incineration of Pteris vittata, an As-hyperaccumulator, was investigated. Incineration results reveal that 24% of total As accumulated by P.

Determination of copper binding in Pseudomonas putida CZ1 by chemical modifications and X-ray absorption spectroscopy.

Previously performed studies have shown that Pseudomonas putida CZ1 biomass can bind an appreciable amount of Cu(II) and Zn(II) ions from aqueous solutions. The mechanisms of Cu- and Zn-binding by P. putida CZ1 were ascertained by chemical modifications of the biomass followed by Fourier transform infrared and X-ray absorption spectroscopic analyses of the living or nonliving cells.

XAFS studies and computational simulation of calixcrowns-caesium complexes in solution.

Caesium L(3)-edge XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure) have been evaluated as means of probing the local structure and the interaction of caesium ions with BPC6 {1,3-alternate bis(2-propyloxy)calix[4]arenecrown-6}, BOC6 {1,3-alternate bis(octyloxy)calix[4]arenecrown-6} and BisC6 (1,3-alternate calix[4]arene bis-crown-6) in NPME (o-nitrophenyl methyl ether) or OA (n-octyl alcohol). The XANES results indicate that the molecular symmetry is enhanced as the caesium ions are embedded. The EXAFS spectra demonstrate that the coordination numbers (N) and average distances (R) from the central caesium ion to the O atoms are: for BPC6, N = 7.