SEARCH · Engineering Papers

Results for “Mg-P”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

5 records

All sources NASA NTRS DOE OSTI

DOE OSTI2021

Engineering Calcium-Bearing Mineral/Hydrogel Composites for Effective Phosphate Recovery

Effectively recovering phosphate from wastewater streams and reutilizing it as a nutrient will critically support sustainability. Here, to capture aqueous phosphate, we developed novel mineral-hydrogel composites composed of calcium alginate, calcium phosphate (CaP), and calcium silicate (CSH) (CaP + CSH/Ca-Alg). The CaP + CSH/Ca-Alg composites were synthesized by dripping a sodium alginate (Na-Alg) solution with ionic precursors into a calcium chloride bath. To change the mineral seed’s properties, we varied the calcium bath concentrations and the ionic precursor (sodium dibasic phosphate (NaH 2 PO 4 ) and/or sodium silicate (Na 2 SiO 3 )) amounts and their ratios. The added CSH in the mineral-hydrogel composites resulted in the release of calcium and silicate ions in phosphate-rich solutions, increasing the saturation ratio with respect to calcium phosphate within the mineral-hydrogel composites. The CSH addition to the mineral-hydrogel composites doubled the phosphate removal rate while requiring lesser initial amounts of Ca and P materials for synthesis. Furthermore, by incorporating both CSH and CaP mineral seeds in composites, we achieved a final concentration of 0.25 mg-P/L from an initial 6.20 mg-P/L. Moreover, the mineral-hydrogel composites can remove phosphate even under CaP undersaturated conditions. This suggests their potential to be a widely applicable and environmentally-sustainable treatment and recovery method for nutrient-rich wastewater.

42 ENGINEERING↗

DOE OSTI2024

Development and Validation of a Process Model and Open-Source Process Simulator for Microalgae-Based Tertiary Phosphorus Recovery

Microalgae-based tertiary wastewater treatment has the potential to meet stringent effluent phosphorus limits, with the added benefit of producing a marketable feedstock. However, the lack of validated mechanistic models and their implementation in process simulators have limited the adoption of this technology. In this study, an updated lumped pathway metabolic model (Phototrophic-Mixotrophic Process Model, PM 2 ), including both photoautotrophic and heterotrophic metabolisms of microalgae, was developed to predict effluent phosphorus concentration and biomass yield in response to dynamic influent and varying environmental conditions. The model was implemented in QSDsan – an open-source, Python-based design and simulation platform – for robust simulation under uncertainty. A global sensitivity analysis was performed to prioritize model parameters for calibration. The model was then calibrated and validated using batch experimental data and 45 days of continuous online monitoring data from a full-scale (568 m 3 ·d -1 ) microalgae-based tertiary wastewater treatment plant (EcoRecover process). In particular, along with dynamic influent composition, temperature and light intensity data with diel variation were provided as model inputs to reflect the microalgal behavior under day-night cycling. Overall, the QSDsan-based microalgae process simulator was able to predict effluent phosphorus within 0.02–0.04 mg-P·L -1 , while also capturing the general trends of state variables according to nutrient availability.

Lumped pathway metabolic model↗

NASA NTRSDate not supplied

Thermodynamic Modeling of the Vapor in Equilibrium With Apollo 17 Basalts.

Lunar mare basalts sampled during the Apollo 17 mission provide insight to the chemical evolution of mare basalt magmas and their associated vapor as these samples erupted and cooled rapidly at the lunar surface. We focus on minerals present on vesicle and vug surfaces in Apollo 17 basalts, such as 71036, which was opened as part of the Apollo Next Generation Sample Analysis (ANGSA) program. The mineral assemblage observed includes native Fe, SiO2, and a Mg-P mineral, possibly merrillite [1, 2]. The pet-rographic context of these phases suggests that they may have been deposited directly from the vapor phase after eruption. Here we use thermodynamic modeling to assess the plausibility of the vapor-phase deposition hypothesis.

D. L. Thompson↗

DOE OSTI2020

Materials Data on MgP4 by Materials Project

MgP4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Mg2+ is bonded to six P+0.50- atoms to form MgP6 octahedra that share corners with four equivalent MgP6 octahedra and corners with fourteen PMg2P2 tetrahedra. The corner-sharing octahedral tilt angles are 60°. There are a spread of Mg–P bond distances ranging from 2.63–2.89 Å. There are two inequivalent P+0.50- sites. In the first P+0.50- site, P+0.50- is bonded to two equivalent Mg2+ and two equivalent P+0.50- atoms to form distorted PMg2P2 tetrahedra that share corners with two equivalent MgP6 octahedra and corners with fourteen PMg2P2 tetrahedra. The corner-sharing octahedra tilt angles range from 69–70°. There are one shorter (2.19 Å) and one longer (2.20 Å) P–P bond lengths. In the second P+0.50- site, P+0.50- is bonded to one Mg2+ and three P+0.50- atoms to form PMgP3 tetrahedra that share corners with five equivalent MgP6 octahedra and corners with nine PMg2P2 tetrahedra. The corner-sharing octahedra tilt angles range from 56–78°. The P–P bond length is 2.27 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Mg3P2 by Materials Project

Mg3P2 crystallizes in the cubic Pn-3m space group. The structure is three-dimensional. Mg2+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing MgP4 tetrahedra. All Mg–P bond lengths are 2.61 Å. P3- is bonded in a 6-coordinate geometry to six equivalent Mg2+ atoms.

36 MATERIALS SCIENCE↗