[1] Chemical analyses of three Martian soil samples were performed using the Wet Chemistry Laboratories on the 2007 Phoenix Mars Scout Lander. One soil sample was obtained from the top $2 cm (Rosy Red) and two were obtained at $5 cm depth from the ice table interface (Sorceress 1 and Sorceress 2). When mixed with water in a $1:25 soil to solution ratio (by volume), a portion of the soil components solvated. Ion concentrations were measured using an array of ion selective electrodes and solution conductivity using a conductivity cell. The measured concentrations represent the minimum leachable ions in the soil and do not take into account species remaining in the soil. Described is the data processing and analysis for determining concentrations of seven ionic species directly measured in the soil/solution mixture. There were no significant differences in concentrations, pH, or conductivity, between the three samples. Using laboratory experiments, refinement of the surface calibrations, and modeling, we have determined a pH for the soil solution of 7.7(±0.3), under prevalent conditions, carbonate buffering, and P CO2 in the cell headspace. Perchlorate was the dominant anion in solution with a concentration for Rosy Red of 2.7(±1) mM. Equilibrium modeling indicates that measured [Ca 2+ ] at 0.56(±0.5) mM and [Mg 2+ ] at 2.9(±1.5) mM, are consistent with carbonate equilibrium for a saturated solution. The [Na + ] and [K + ] were 1.4(±0.6), and 0.36(±0.3) mM, respectively. Results indicate that the leached portion of soils at the Phoenix landing site are slightly alkaline and dominated by carbonate and perchlorate. However, it should be noted that there is a 5-15 mM discrepancy between measured ions and conductivity and another species may be present.

Sulfur has been detected by X‐ray spectroscopy in martian soils at the Viking, Pathfinder, Opportunity and Spirit landing sites. Sulfates have been identified by OMEGA and CRISM in Valles Marineris and by the spectrometers on the MER rovers at Meridiani and Gusev. The ubiquitous presence of sulfur has been interpreted as a widely distributed sulfate mineralogy. One goal of the Wet Chemistry Laboratory (WCL) on NASA's Phoenix Mars Lander was to determine soluble sulfate in the martian soil. We report here the first in‐situ measurement of soluble sulfate equivalent to ∼1.3(±0.5) wt% as SO4 in the soil. The results and models reveal SO42− predominately as MgSO4 with some CaSO4. If the soil had been wet in the past, epsomite and gypsum would be formed from evaporation. The WCL‐derived salt composition indicates that if the soil at the Phoenix site were to form an aqueous solution by natural means, the water activity for a dilution of greater than ∼0.015 g H2O/g soil would be in the habitable range of known terrestrial halophilic microbes.

Sequestration of trivalent actinides and lanthanides present in used nuclear fuel and legacy wastes is necessary for appropriate long-term stewardship of these metals, particularly to prevent their release into the environment. Organically modified mesoporous silica is an efficient material for recovery and potential subsequent separation of actinides and lanthanides because of its high surface area, tunable ligand selection, and chemically robust substrate. We have synthesized the first novel hybrid material composed of SBA-15 type mesoporous silica functionalized with diglycolamide ligands (DGA-SBA). Because of the high surface area substrate, the DGA-SBA was found to have the highest Eu capacity reported so far in the literature of all DGA solid-phase extractants. The sorption behavior of europium and americium on DGA-SBA in nitric and hydrochloric acid media was tested in batch contact experiments. DGA-SBA was found to have high sorption of Am and Eu in pH 1, 1 M, and 3 M nitric and hydrochloric acid concentrations, which makes it promising for sequestration of these metals from used nuclear fuel or legacy waste. The kinetics of Eu sorption were found to be two times slower than that for Am in 1 M HNO3. Additionally, the short-term susceptibility of DGA-SBA to degradation in the presence of acid was probed using (29)Si and (13)C solid-state NMR spectroscopy. The material was found to be relatively stable under these conditions, with the ligand remaining intact after 24 h of contact with 1 M HNO3, an important consideration in use of the DGA-SBA as an extractant from acidic media.

The upcoming Facility for Rare Isotope Beams (FRIB) at Michigan State University provides a new opportunity to access some of the world’s most specialized scientific resources: radioisotopes. An excess of useful radioisotopes will be formed as FRIB fulfills its basic science mission of providing rare isotope beams. In order for the FRIB beams to reach high-purity, many of the isotopes are discarded and go unused. If harvested, the unused isotopes could enable new research for diverse applications ranging from medical therapy and diagnosis to nuclear security. Given that FRIB will have the capability to create about 80% of all possible atomic nuclei, harvesting at FRIB will provide a fast path for access to a vast array of isotopes of interest in basic and applied science investigations. To fully realize this opportunity, infrastructure investment is required to enable harvesting and purification of otherwise unused isotopes. An investment in isotope harvesting at FRIB will provide a powerful resource for development of crucial isotope applications. In 2010, the United States Department of Energy Office of Science, Nuclear Physics, sponsored the first ‘Workshop on Isotope Harvesting at FRIB’, convening researchers from diverse fields to discuss the scientific impact and technical feasibility of isotope harvesting. Following the initial meeting, a series of biennial workshops was organized. At the fourth workshop, at Michigan State University in 2016, the community elected to prepare a formal document to present their findings. This report is the output of the working group, drawing on contributions and discussions with a broad range of scientific experts.

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