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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Inhibiting ACK1-mediated phosphorylation of C-terminal Src kinase counteracts prostate cancer immune checkpoint blockade resistance

Solid tumours are highly refractory to immune checkpoint blockade (ICB) therapies due to the functional impairment of effector T cells and their inefficient trafficking to tumours. T-cell activation is negatively regulated by C-terminal Src kinase (CSK); however, the exact mechanism remains unknown. Here we show that the conserved oncogenic tyrosine kinase Activated CDC42 kinase 1 (ACK1) is able to phosphorylate CSK at Tyrosine 18 (pY18), which enhances CSK function, constraining T-cell activation. Mice deficient in the Tnk2 gene encoding Ack1, are characterized by diminished CSK Y18-phosphorylation and spontaneous activation of CD 8+ and CD 4+ T cells, resulting in inhibited growth of transplanted ICB-resistant tumours. Furthermore, ICB treatment of castration-resistant prostate cancer (CRPC) patients results in re-activation of ACK1/pY18-CSK signalling, confirming the involvement of this pathway in ICB insensitivity. An ACK1 small-molecule inhibitor, (R)-9b, recapitulates inhibition of ICB-resistant tumours, which provides evidence for ACK1 enzymatic activity playing a pivotal role in generating ICB resistance. Overall, our study identifies an important mechanism of ICB resistance and holds potential for expanding the scope of ICB therapy to tumours that are currently unresponsive.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Evaporation and scattering of neon, methane, and water from a dodecane flat liquid jet

The evaporation and scattering of Ne, CD 4 , and D 2 O from a dodecane flat liquid jet are investigated in a molecular beam apparatus. The experiment yields translational energy distributions as a function of scattering angle by means of a rotatable mass spectrometer. In the evaporation experiments, one observes a Maxwell–Boltzmann distribution with a cos $θ$ angular distribution superimposed on a weak, isotropic background. The scattering experiments show contributions from impulsive scattering and thermal desorption. At select incident angles for the three systems, angular distributions show super-specular scattering for the impulsive scattering channel, an effect attributed to anisotropic momentum transfer to the liquid surface. The impulsive scattering channel is analyzed with a soft-sphere model to explore energy transfer between the scatterer and liquid as a function of deflection angle. In conclusion, compared to Ne scattering, the polyatomic gases exhibit more thermal desorption and, in the impulsive scattering channel, a higher degree of internal excitation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Cd(CN)2 by Materials Project

Cd(CN)2 is Tungsten structured and crystallizes in the cubic P-43m space group. The structure is zero-dimensional and consists of one cadmium molecule and one Cd(CN)4 cluster. In the Cd(CN)4 cluster, Cd2+ is bonded in a tetrahedral geometry to four equivalent N3- atoms. All Cd–N bond lengths are 2.19 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Cd2+ and one C2+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1972

NiCd battery electrodes, C-150

Electrodes for a nongassing negative limited nickel-cadmium cell are discussed. The key element is the development of cadmium electrodes with high hydrogen overvoltage. For this, the following electrode structures were manufactured and their physical and electrochemical characteristics were evaluated: (1) silver-sinter-based Cd electrodes, (2) Teflon-bonded Cd electrodes, (3) electrodeposited Cd sponge, and (4) Cd-sinter structures.

Holleck, G.↗
NASA NTRS1972

NiCd battery electrodes

The objective of this research program was to develop and evaluate electrodes for a negative limited nickel-cadmium cell and to prove its feasibility. The program consisted of three phases: (1) the development of cadmium electrodes with high hydrogen overvoltage characteristics, (2) the testing of positive and negative plates, and (3) the fabrication and testing of complete negative limited NiCd cells. The following electrode structures were manufactured and their physical and electrochemical characteristics were evaluated: (1) silver sinter-based Cd electrodes, (2) Teflon-bonded Cd electrodes, (3) electrodeposited Cd sponge, and (4) Cd-sinter structures. All cadmium electrode structures showed a sharp increase in potential at the end of charge, with the advent of hydrogen evolution occurring at approximately -1.3 V versus Hg/HgO. The hydrogen advent potentials on pure cadmium structures were 50 to 70 mV more cathodic than those of their silver-containing counterparts.

Holleck, G.↗
NASA NTRS2003

The Origin and Distribution of Heavy Elements in the CD Groups MKW 4 and AWM 4

At this point, data for MKW4 have been received and those for AWM4 are still awaited. The MKW4 data have been fully analyzed and a complete manuscript is available and in final review by co-authors before submission for refereed publication. The following is a summary of our principal findings: We examined the distribution and properties of the hot gas which makes up the group halo. The inner halo shows some signs of structure, with circular or elliptical beta-models providing a poor fit to the surface brightness profile. This may be evidence of large-scale motion in the inner halo, but we do not find evidence of sharp fronts or edges in the emission. The temperature of the halo declines in the core, with deprojected spectral fits showing a central temperature of approximately 1.3keV compared to approximately 3keV at 250 arcsec. However, cooling flow models provide poor fits to the inner regions of the group and the estimated cooling time of the gas is long except within the central dominant galaxy, NGC4073. Abundance profiles show a sharp increase in the core of the group. We conclude that MKW4 is a fairly relaxed group, which has developed a strong central temperature gradient but not a large-scale cooling flow.

Vrtilek, Jan↗
DOE OSTI2020

Materials Data on CdHC2(NO)4 by Materials Project

(Cd)2(N2)4(CO2)4H2 is Cyanogen Chloride-derived structured and crystallizes in the orthorhombic Pbcn space group. The structure is zero-dimensional and consists of four cadmium molecules, eight carbon dioxide molecules, four hydrogen molecules, and eight nitrogen molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Heat capacity and thermodynamic functions of partially dehydrated cation-exchanged (Na + , Cs + , Cd 2+ , Li + , and NH 4 + ) $\mathrm{RHO}$ zeolites

Synthetic zeolites have a myriad of applications in industry due to their porous frameworks, potential to exhibit flexibility, and specific interactions with guest molecules. One topology of zeolites, RHO, is known to be flexible and have strong interactions with both H 2 O and CO 2 . Here we have performed heat capacity measurements on three partially dehydrated zeolite RHO samples containing extra-framework cations Na + and Cs + , Cd 2+ and Cs + , and Li + and NH 4 + to understand the energetics of these materials. Based on fits of the heat capacity data, we report smooth thermodynamic functions of C p,m , Δ T 0 S m °, Δ T 0 H m °, and Φ m ° for these samples. The standard S m ° at 298.15 K are 76.3 ± 0.8, 72.1 ± 0.8, and 68.8 ± 0.7 J∙K -1 ∙mol -1 for the Na,Cs RHO, Cd,Cs RHO, and Li,NH 4 RHO samples, respectively, and the standard H m ° at 298.15 K are 12.1 ± 0.1, 11.4 ± 0.1, and 11.4 ± 0.1 kJ∙mol -1 . Our measurements also show a transition in the heat capacity of Na,Cs RHO, the sample with the highest water content, between 180 and 300 K that is not clearly observed in the other two samples. We attribute this transition to labile water and cations in the framework. This movement could also be coupled with a temperature-induced lattice expansion. Future work will include heat capacity measurements on fully dehydrated and fully hydrated zeolite RHO in order to separate these two possible phenomena.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2001

Second Generation RLV Program

During the time period covered by this report, SAIC: 1) Continued to develop and assess processes and approaches that can be applied to Second Generation Reuseable Launch Vehicles (RLV) technologies prioritization. An approach based on the use of analytic Saaty scale functions has been defined and is being investigated. 2) Planned and facilitated technologies prioritization workshops, supported development of systems program algorithms based on the concept of influence diagramming, and assessment of analogies between aircraft and space systems developments. 3) Video interviews held with X-37 personnel at Dryden. The CD-ROM is being concluded and a near-final review disc is expected soon. 4) CD-ROMS were produced by Engineered Multimedia, Inc. (EMI) under subcontract to SAIC. These two CD-ROM products, "Microgravity" and "New Horizons", were delivered to MSFS technical representatives at a briefing at SAID on January 18, 2001. 5) Presentation brochure, "Aviation/Space Analog Team Interim Report" was provided to Space Propulsion Synergy Team (SPST) members and to NASA personnel. Wrap-up of effort will be a mid-April briefing to both MSFC and the full SPST membership. Support to Phase 2 of CCPD ends 3/31/01. Phase 3 continuation effort planned with emphasis on technical info content. 6) Recommended that eliminating the B-52 flights of the X-37 in favor of alternate approached be evaluated. Discovered that a required change to the thruster valves of the X-37 had not been made. Repair work continues on the lower fuselage section of the X-37, in the areas that experienced core collapse. The currently catalogued potential weight increases and decreases are about equal, but this does not include the impact of the cable weight underestimate reported earlier. The CFD for RCS testing correlates well with the wind tunnel data. 7) The Level IV CCB approved SCN-4 to the MC-1 Engine SPecification. Approved changes have been incorporated into the specification, and Revision D has been released to the Repository. Billy Gonterman, SAIC, traveled to SSC to perform a five-day readiness assessment on the progress of facilities activation. Implemented modifications to the MC-1 Engine TPA Component Database. 8) Replaced 25 Combined-Cycle Propulsion Database (CCPD) documents; modified the low-on screen to include a direct email link for user contact; prepared a summary presentation of current and proposed tasks.

Laue, Jay↗
DOE OSTI2023

Interface atomic structures in a cadmium arsenide/III–V semiconductor heterostructure

The interface atomic structure between an epitaxial thin film of the prototype topological semimetal cadmium arsenide (Cd 3 As 2 ) and a III–V semiconductor layer is investigated using high-angle annular dark-field imaging in an aberration-corrected scanning transmission electron microscope. We find that the interface unit cell adopts a defined stoichiometry that is CdSb-like, which is achieved through the insertion of periodically arranged Cd vacancies in the terminating Cd-plane of Cd 3 As 2 . This interface stoichiometry is consistent with the Sb-termination of the III–V layer and the fact that CdSb is the thermodynamically stable phase in the Cd–Sb binary system. We find at least two distinct alignments of the film with respect to the buffer layer, which are characterized by a $\frac{1}{4}$ <100> Cd 3 As 2 shift parallel to the interface. We show that steps of half unit cell height in the III–V layer can produce these distinct interface structures.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2022

Elucidating structure and dynamics of crystalline α-zirconium phosphates intercalated with water and methanol by multinuclear solid-state MAS NMR: A comprehensive NMR approach

Solid-state NMR experiments on 2 H, 31 P, 13 C, and 1 H nuclei, including 31 P T 1 , 1 H T 1 , and 1 H T 1ρ measurements, as well as on the kinetics of proton-phosphorus cross-polarization have been performed to characterize the crystalline and amorphous α-zirconium phosphates, which were intercalated with D 2 O and/or CD 3 OD. The 13 C{ 1 H} CP MAS NMR experiment performed for compound 1-CD 3 OD (Zr (HPO 4 ) 2 .0.2CD 3 OD) with carbon cross-polarization via protons of phosphate groups has provided a prove that the methanol was intercalated into the interlayer spaces of this compound. The variable-temperature 2 H solid-echo MAS NMR spectra of intercalated compounds demonstrated that the methanol molecules, in contrast to the mobile water, were immobile, keeping, however, free CD 3 rotations around the C 3 -axis. It has been demonstrated that the intercalated species, D 2 O and CD 3 OD, do not affect the high-frequency motions of the phosphate groups. By utilizing local structural models that satisfy the constraints of the experimental data, it has been suggested that the immobile methanol molecules are located in the cavity between two neighboring layers of the zirconium phosphates. Here, the present work illustrates the reliable criteria in a comprehensive NMR approach to structural and dynamic studies of such systems.

1H↗
DOE OSTI2020

Materials Data on CdPb3Se4 by Materials Project

CdPb3Se4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cd2+ is bonded to six equivalent Se2- atoms to form CdSe6 octahedra that share corners with six equivalent PbSe6 octahedra, edges with six equivalent CdSe6 octahedra, and edges with six equivalent PbSe6 octahedra. The corner-sharing octahedral tilt angles are 4°. All Cd–Se bond lengths are 2.94 Å. There are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to six Se2- atoms to form PbSe6 octahedra that share corners with three equivalent CdSe6 octahedra, corners with three equivalent PbSe6 octahedra, edges with three equivalent CdSe6 octahedra, and edges with nine PbSe6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are three shorter (3.08 Å) and three longer (3.12 Å) Pb–Se bond lengths. In the second Pb2+ site, Pb2+ is bonded to six equivalent Se2- atoms to form a mixture of edge and corner-sharing PbSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Pb–Se bond lengths are 3.09 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to six Pb2+ atoms to form a mixture of edge and corner-sharing SePb6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second Se2- site, Se2- is bonded to three equivalent Cd2+ and three equivalent Pb2+ atoms to form a mixture of edge and corner-sharing SeCd3Pb3 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Ba 6 (Cu x Z y )Sn 4 S 16 (Z = Mg, Mn, Zn, Cd, In, Bi, Sn): High Chemical Flexibility Resulting in Good Nonlinear-Optical Properties

Seven acentric sulfides Ba 6 (Cu x Z y )Sn 4 S 16 (Z = Mg, Mn, Zn, Cd, In, Bi, Sn) were grown by a high-temperature salt flux method. The crystal structures of the Ba 6 (Cu x Z y )Sn 4 S 16 (Z = Mg, Mn, Zn, Cd, In, Bi, Sn) compounds were determined by single-crystal X-ray diffraction with the aid of solid-state NMR spectroscopy. The Ba 6 (Cu x Z y )Sn 4 S 16 (Z = Mg, Mn, Zn, Cd, In, Bi) compounds are isostructural and crystallize in the Ba 6 Ag 4 Sn 4 S 16 structure type. The Sn-containing compound exhibits high structural similarity to Ba 6 (Cu x Z y )Sn 4 S 16 (Z = Mg, Mn, Zn, Cd, In, Bi) with the presence of an interstitial atomic position partially occupied by Sn atoms. The chemical bonding characteristics of Ba 6 (Cu 2.9 Sn 0.4 )Sn 4 S 16 were understood with electron localization function calculations coupled with crystal orbital Hamilton population calculations. The Ba–S and Cu–S interactions are dominantly ionic, but the Sn–S interactions consist of strong covalent bonding characteristics in Ba 6 (Cu 2.9 Sn 0.4 )Sn 4 S 16 . The monovalent Cu atoms, mixed with certain metals with various oxidation states, significantly shift the optical properties of the Ba 6 (Cu x Z y )Sn 4 S 16 (Z = Mg, Mn, Zn, Cd, In, Bi) compounds. This results in a good balance between the second-harmonic-generation (SHG) response and laser damage threshold (LDT). Ba 6 (Cu 1.9 Zn 1.1 )Sn 4 S 16 possesses a high SHG response and a high LDT of 2.8 × AGS and 3 × AGS, respectively. Here, a density functional theory calculation revealed that CuS 4 and SnS 4 tetrahedra significantly contribute to the SHG response in Ba 6 (Cu 2 Mg)Sn 4 S 16 , which also confirmed that CuS 4 tetrahedra are crucial for the stability and optical properties of the Ba 6 (Cu x Z y )Sn 4 S 16 (Z = Mg, Mn, Zn, Cd, In, Bi, Sn) compounds revealed by electronic structure analysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Cd2Bi2(TeSe)3 by Materials Project

Cd2Bi2(TeSe)3 is Caswellsilverite-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to three equivalent Te2- and three equivalent Se2- atoms to form CdTe3Se3 octahedra that share corners with three equivalent BiSe6 octahedra, edges with three equivalent BiSe6 octahedra, and edges with six equivalent CdTe3Se3 octahedra. The corner-sharing octahedral tilt angles are 4°. All Cd–Te bond lengths are 2.96 Å. All Cd–Se bond lengths are 2.96 Å. In the second Cd2+ site, Cd2+ is bonded to three equivalent Te2- and three equivalent Se2- atoms to form CdTe3Se3 octahedra that share corners with three equivalent BiTe3Se3 octahedra, corners with three equivalent SeBi3Te3 octahedra, edges with three equivalent BiTe3Se3 octahedra, edges with three equivalent SeBi3Te3 octahedra, and edges with six equivalent CdTe3Se3 octahedra. The corner-sharing octahedra tilt angles range from 2–15°. All Cd–Te bond lengths are 2.91 Å. All Cd–Se bond lengths are 3.01 Å. There are two inequivalent Bi4+ sites. In the first Bi4+ site, Bi4+ is bonded to three equivalent Te2- and three equivalent Se2- atoms to form BiTe3Se3 octahedra that share corners with three equivalent CdTe3Se3 octahedra, edges with three equivalent CdTe3Se3 octahedra, and edges with six equivalent BiTe3Se3 octahedra. The corner-sharing octahedral tilt angles are 2°. All Bi–Te bond lengths are 3.09 Å. All Bi–Se bond lengths are 3.08 Å. In the second Bi4+ site, Bi4+ is bonded to six Se2- atoms to form BiSe6 octahedra that share corners with three equivalent CdTe3Se3 octahedra, corners with three equivalent TeCd3Se3 octahedra, edges with three equivalent CdTe3Se3 octahedra, edges with three equivalent TeCd3Se3 octahedra, and edges with six equivalent BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–14°. There are three shorter (2.91 Å) and three longer (3.12 Å) Bi–Se bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Cd2+ and three equivalent Te2- atoms. All Te–Te bond lengths are 3.46 Å. In the second Te2- site, Te2- is bonded to three equivalent Cd2+ and three equivalent Se2- atoms to form distorted TeCd3Se3 octahedra that share corners with three equivalent BiSe6 octahedra, corners with three equivalent SeCd3Bi3 octahedra, edges with three equivalent BiSe6 octahedra, edges with three equivalent SeCd3Bi3 octahedra, and edges with six equivalent TeCd3Se3 octahedra. The corner-sharing octahedra tilt angles range from 3–14°. All Te–Se bond lengths are 3.60 Å. In the third Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Bi4+ and three equivalent Te2- atoms. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Bi4+ and three equivalent Te2- atoms to form distorted SeBi3Te3 octahedra that share corners with three equivalent CdTe3Se3 octahedra, corners with three equivalent SeCd3Bi3 octahedra, edges with three equivalent CdTe3Se3 octahedra, and edges with nine SeBi3Te3 octahedra. The corner-sharing octahedra tilt angles range from 5–15°. In the second Se2- site, Se2- is bonded to three equivalent Cd2+ and three equivalent Bi4+ atoms to form a mixture of corner and edge-sharing SeCd3Bi3 octahedra. The corner-sharing octahedral tilt angles are 5°. In the third Se2- site, Se2- is bonded to three equivalent Cd2+ and three equivalent Bi4+ atoms to form SeCd3Bi3 octahedra that share corners with three equivalent TeCd3Se3 octahedra, edges with three equivalent TeCd3Se3 octahedra, and edges with six equivalent SeCd3Bi3 octahedra. The corner-sharing octahedral tilt angles are 3°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3Ta2CdO9 by Materials Project

Ba3Ta2CdO9 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, faces with three equivalent CdO6 octahedra, and faces with five equivalent TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.98–3.06 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with two equivalent CdO6 octahedra, and faces with six equivalent TaO6 octahedra. There are six shorter (2.94 Å) and six longer (2.98 Å) Ba–O bond lengths. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CdO6 octahedra, and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are three shorter (1.93 Å) and three longer (2.12 Å) Ta–O bond lengths. Cd2+ is bonded to six equivalent O2- atoms to form CdO6 octahedra that share corners with six equivalent TaO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 4°. All Cd–O bond lengths are 2.29 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+, one Ta5+, and one Cd2+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MnCdO2 by Materials Project

MnCdO2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Mn2+ is bonded to six equivalent O2- atoms to form MnO6 octahedra that share corners with six equivalent CdO6 octahedra, edges with six equivalent MnO6 octahedra, and edges with six equivalent CdO6 octahedra. The corner-sharing octahedral tilt angles are 4°. All Mn–O bond lengths are 2.26 Å. Cd2+ is bonded to six equivalent O2- atoms to form CdO6 octahedra that share corners with six equivalent MnO6 octahedra, edges with six equivalent MnO6 octahedra, and edges with six equivalent CdO6 octahedra. The corner-sharing octahedral tilt angles are 4°. All Cd–O bond lengths are 2.39 Å. O2- is bonded to three equivalent Mn2+ and three equivalent Cd2+ atoms to form a mixture of edge and corner-sharing OMn3Cd3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3Nb2CdO9 by Materials Project

Ba3Nb2CdO9 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with two equivalent CdO6 octahedra, and faces with six equivalent NbO6 octahedra. There are six shorter (2.95 Å) and six longer (2.99 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, faces with three equivalent CdO6 octahedra, and faces with five equivalent NbO6 octahedra. There are nine shorter (2.99 Å) and three longer (3.08 Å) Ba–O bond lengths. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent NbO6 octahedra, corners with three equivalent CdO6 octahedra, and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are three shorter (1.94 Å) and three longer (2.13 Å) Nb–O bond lengths. Cd2+ is bonded to six equivalent O2- atoms to form CdO6 octahedra that share corners with six equivalent NbO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 4°. All Cd–O bond lengths are 2.28 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+, one Nb5+, and one Cd2+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two equivalent Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Elucidating Phosphate and Cadmium Cosorption Mechanisms on Mineral Surfaces with Direct Spectroscopic and Modeling Evidence

The simultaneous sorption of cations and anions at the mineral–water interface can substantially alter their individual sorption characteristics; however, this phenomenon lacks a mechanistic understanding. Our study provides direct spectroscopic and modeling evidence of the molecular cosorption mechanisms of the cadmium ion (Cd 2+ ) and phosphate (P) on goethite and layered manganese (Mn) oxide of birnessite, through in situ attenuated total reflection Fourier-transform infrared (ATR-FTIR), P K-edge X-ray absorption near-edge structure (XANES) spectroscopy, and surface complexation modeling. Phosphate synergistically cosorbed with Cd on goethite predominantly through P-bridged ternary complexes (≡Fe–P–Cd) and electrostatic interactions at wide pH conditions. Likewise, P and Cd exhibited synergistic cosorption on birnessite by forming P-bridged ternary complexes (≡Mn–P–Cd) and weak competitive sorption at the layer edge sites. As pH and Cd loading increased, the surface P species transitioned from a binary complex to a ternary complex and/or Cd 3 (PO 4 ) 2 precipitate for both goethite and birnessite. Compared to that in solution at pH 8, the formation of Cd 3 (PO 4 ) 2 was inhibited by the presence of goethite and birnessite, ascribed to the specific adsorption of P and Cd, more pronounced in birnessite due to the stronger sorption of Cd at its vacant sites. Finally, the discovered cosorption mechanisms of P and Cd have important implications for understanding and predicting their mobility and availability in Cd-contaminated settings.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗