I-Xe systematics of the impact plume produced chondrules from the CB carbonaceous chondrites: Implications for the half-life value of 129I and absolute age normalization of 129I-129Xe chronometer

History of the solar nebula from meteorite paleomagnetism

We review recent advances in our understanding of magnetism in the solar nebula and protoplanetary disks (PPDs). We discuss the implications of theory, meteorite measurements, and astronomical observations for planetary formation and nebular evolution. Paleomagnetic measurements indicate the presence of fields of 0.54 ± 0.21 G at ~1 to 3 astronomical units (AU) from the Sun and ≳0.06 G at 3 to 7 AU until >1.22 and >2.51 million years (Ma) after solar system formation, respectively. These intensities are consistent with those predicted to enable typical astronomically observed protostellar accretion rates of ~10^-8 M _⊙year^-1, suggesting that magnetism played a central role in mass transport in PPDs. Paleomagnetic studies also indicate fields <0.006 G and <0.003 G in the inner and outer solar system by 3.94 and 4.89 Ma, respectively, consistent with the nebular gas having dispersed by this time. This is similar to the observed lifetimes of extrasolar protoplanetary disks.

Selective immobilization of iodide onto a novel bismuth-impregnated layered mixed metal oxide: Batch and EXAFS studies

A novel Mg/Al/Bi ternary mixed metal oxide (MMO) was successfully prepared by a simple coprecipitation and calcination process. The Mg/Al/Bi MMO (molar ratio = 3:0.4:0.6) presented synergistically enhanced adsorption efficiency for iodide in water with porous structure. Kinetic adsorption results indicated good agreement with pseudo first-order-kinetic model (R = 0.998) and the maximum adsorption capacity calculated by Langmuir isotherm of Mg/Al/Bi MMO was 202.2 mg/g, which is higher than that of Mg/Al layered double oxide (LDO) (161.0 mg/g) and bismuth oxide (57.5 mg/g). In addition, the Mg/Al/Bi MMO showed good adsorption efficiency under neutral condition (pH 7), by which the material exhibits relatively strong resistance to the presence of co-existing anions in water due to the ion selectivity. Extended X-ray absorption fine structure (EXAFS) spectra revealed that the enhanced adsorption of iodide by Mg/Al/Bi MMO can be induced by selective Bi-O-IBformation, which is stable waste form for its treatment. Consequently, it is clear that the novel Mg/Al/Bi MMO is a potentially attractive material in terms of selective uptake of iodide with forming stable chemical complex in radioactive contaminants.