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SO4 is Silicon tetrafluoride-like structured and crystallizes in the cubic F-43m space group. The structure is zero-dimensional and consists of four sulfuric acid molecules. S is bonded in a tetrahedral geometry to four equivalent O atoms. All S–O bond lengths are 1.48 Å. O is bonded in a single-bond geometry to one S atom.
Ru(Cl)(NH3)5(H2O)4(SO4)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of ten ammonia molecules, two chlororuthenium molecules, four sulfuric acid molecules, and eight water molecules.
SO5 is Silicon tetrafluoride-like structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is zero-dimensional and consists of four sulfuric acid, monohydrate molecules. S is bonded in a tetrahedral geometry to four O atoms. There are a spread of S–O bond distances ranging from 1.47–1.53 Å. There are five inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one S and one O atom. The O–O bond length is 2.02 Å. In the second O site, O is bonded in a single-bond geometry to one O atom. In the third O site, O is bonded in a single-bond geometry to one S atom. In the fourth O site, O is bonded in a single-bond geometry to one S atom. In the fifth O site, O is bonded in a single-bond geometry to one S atom.
OSO5 is Iron carbide-like structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of twelve sulfuric acid molecules and twenty-four water molecules.
N2AsO4SO4 is Iron carbide-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of eight ammonia molecules, four sulfuric acid molecules, and four AsO4 clusters. In each AsO4 cluster, As2+ is bonded in a tetrahedral geometry to four O2- atoms. There is one shorter (1.71 Å) and three longer (1.73 Å) As–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one As2+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one As2+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one As2+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one As2+ atom.
SO4 is Silicon tetrafluoride-like structured and crystallizes in the monoclinic Cc space group. The structure is zero-dimensional and consists of four sulfuric acid molecules. S is bonded in a tetrahedral geometry to four O atoms. There is three shorter (1.48 Å) and one longer (1.49 Å) S–O bond length. There are four inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one S atom. In the second O site, O is bonded in a single-bond geometry to one S atom. In the third O site, O is bonded in a single-bond geometry to one S atom. In the fourth O site, O is bonded in a single-bond geometry to one S atom.
(CH3)6C2BiH6S5O8HSO4 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of twelve methane molecules; one sulfate, hydrogen, compd. with sulfuric acid (1:1) molecule; and one C2BiH6S5O8 cluster. In the C2BiH6S5O8 cluster, there are two inequivalent C1+ sites. In the first C1+ site, C1+ is bonded in a trigonal non-coplanar geometry to three H1+ and one S2- atom. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. The C–S bond length is 1.79 Å. In the second C1+ site, C1+ is bonded in a trigonal non-coplanar geometry to three H1+ and one S2- atom. All C–H bond lengths are 1.10 Å. The C–S bond length is 1.79 Å. Bi3+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of Bi–O bond distances ranging from 2.36–3.02 Å. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C1+ atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C1+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C1+ atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C1+ atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C1+ atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C1+ atom. There are five inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted single-bond geometry to one O2- atom. The S–O bond length is 1.55 Å. In the second S2- site, S2- is bonded in a distorted trigonal non-coplanar geometry to two C1+ and one O2- atom. The S–O bond length is 1.53 Å. In the third S2- site, S2- is bonded in a distorted single-bond geometry to one O2- atom. The S–O bond length is 1.55 Å. In the fourth S2- site, S2- is bonded in a distorted single-bond geometry to one O2- atom. The S–O bond length is 1.55 Å. In the fifth S2- site, S2- is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.46–1.53 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Bi3+ and one S2- atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Bi3+ and one S2- atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Bi3+ and one S2- atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Bi3+ and one S2- atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one Bi3+ and one S2- atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Bi3+ and one S2- atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Bi3+ and one S2- atom.
(Na(H2O)4)2Mg(H2O)6(H2O)2(SO4)2 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of one magnesium;hexahydrate molecule; two sulfuric acid molecules; two water molecules; and one Na(H2O)4 ribbon oriented in the (1, 0, 0) direction. In the Na(H2O)4 ribbon, Na1+ is bonded to six O2- atoms to form distorted edge-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.42–2.55 Å. There are eight inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a water-like geometry to one Na1+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Na1+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Na1+ and two H1+ atoms. In the fourth O2- site, O2- is bonded in a water-like geometry to one Na1+ and two H1+ atoms.
SO4 is Silicon tetrafluoride-like structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four sulfuric acid molecules. S is bonded in a tetrahedral geometry to four equivalent O atoms. All S–O bond lengths are 1.48 Å. O is bonded in a single-bond geometry to one S atom.
NaCrO12(SO4)2 crystallizes in the cubic Pa-3 space group. The structure is three-dimensional and consists of eight sulfuric acid molecules and one NaCrO12 framework. In the NaCrO12 framework, Na is bonded in a 6-coordinate geometry to six equivalent O atoms. All Na–O bond lengths are 2.98 Å. Cr is bonded in an octahedral geometry to six equivalent O atoms. All Cr–O bond lengths are 2.12 Å. There are two inequivalent O sites. In the first O site, O is bonded in a distorted bent 120 degrees geometry to one Cr and one O atom. The O–O bond length is 1.25 Å. In the second O site, O is bonded in a bent 120 degrees geometry to one Na and one O atom.
KAlO12(SO4)2 crystallizes in the cubic Pa-3 space group. The structure is three-dimensional and consists of eight sulfuric acid molecules and one KAlO12 framework. In the KAlO12 framework, K is bonded in a distorted octahedral geometry to six equivalent O atoms. All K–O bond lengths are 3.33 Å. Al is bonded in an octahedral geometry to six equivalent O atoms. All Al–O bond lengths are 1.94 Å. There are two inequivalent O sites. In the first O site, O is bonded in a water-like geometry to one K and one O atom. The O–O bond length is 1.27 Å. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Al and one O atom.
The use of Acidithiobacillus ferrooxidans, Thiobacillus thiooxidans, and other chemoautotrophic microbes in bioleaching have been implemented in a variety of processes.1 In industry, bioleaching has been studied for its potential to extract valuable metals from low grade ores that would otherwise be cost prohibitive to recover.2 Other applications of bioleaching include the ability of certain microbes to detoxify waste products and even heavy metal contaminated soils.3 Another potential application for such bio-oxidative microbial activity is the extraction of tellurium (Te) from mine tailings, a low-cost abundant resource. Tellurium is one of the least common elements on Earth; it is found in the planetary crust at about 1 µg/kg, a rarity most comparable to that of platinum.4 A major use of Te in the U.S. is in cadmium-telluride (CdTe) solar panels5. Te is primarily imported into the U.S. from Canada, and it is usually recovered as a byproduct of copper refining.6 Since CdTe photovoltaic (PV) cells are the most efficient, cost-effective, and environmentally friendly PV chemistry, the renewables market has seen an increased demand for CdTe PV cells causing some concerns about sustainability and the limited global availability of Te. Acidithiobacillus ferroxidans is a microorganism that can oxidize iron and sulfur to produce ferric iron and sulfuric acid, and it is possible that it could also solubilize Te from sulfidic mine tailings. In this project, different media for growth of A. ferroxidans were evaluated, and a plan for testing the ability of A. ferroxidans to leach Te from mine tailings was developed. Initial characterization of A. ferroxidans cultures grown in the presence of copper tailings suggests that conditions suitable for Te bioleaching can be established.
This report investigates a laser-interference surface treatment as a non-contact, i.e., without major solid/liquid medium application or abrasion, and non-chemical surface preparation method for aerospace coating systems. It was proposed to use the laser-interference technique to structure surfaces of Al and/or Ti, creating "rough" surfaces with pre-engineered series of ridges and valleys at submicron scale. The science goal of this study was to develop an understanding of the surface microstructure, topology, and physical mechanisms that would improve adhesion and corrosion protection of Al2024-T3. Microstructure analysis indicates that the laser-interference structuring (LIS) was found to reduce the formation of CuMn-rich precipitates in Al 2024-T3 over a 500-800 nm depth from top surface. The X-cut and cross-hatch coating adhesion ratings indicate that the LIS specimens meet the performance requirements in the coating adhesion specifications by having a higher or identical ranking to those specimens prepared with current state-of-the-art chemical conversion or sulfuric acid anodizing. After the ASTM B117 corrosion exposure, it was found that the laser processed specimens exhibited only few blisters. It was found that the corrosion damage was minimized at a laser rastering speed of 4 mm/s, for which only 33% of specimens developed very minor corrosion damage. The ASTM D1654 creepage ratings, used to evaluate corrosion damage along the scribe lines, were found to be at least nine for all coated panels. These results indicate that the laser-interference technique with the additional acetone wiping has the potential to be further developed as a minor chemical surface preparation technique for chromate-containing epoxy primers coatings.
Rare earth elements (REEs) (including scandium, yttrium and a group of 15 lanthanides) are often considered to be critical components in the productions of renewable energy hardware, electric vehicles, health care and military equipment, and consumer electronic products. The demand of REEs has been projected to be growing at an annual rate of 5-9% in the next 25 years. In 2011, the global demand of total rare earth oxides (REOs) was estimated to be approximately 105,000 tons, which is expected to grow to 210,000 tons by 2025. China overwhelmingly dominates the current worldwide rare earth productions but has strategically restricted its exports, causing significant instability for the global market. In response to the increasing demand for REEs and the supply dominance of China, identifying alternative sources of REEs has become a critical issue for the United States and other countries. Coal, coal ash, and coal mine drainage (CMD) are considered to be the alternative sources of REEs. In the U.S., high REE concentrations have been reported to be closely associated with coal deposits, including the Appalachian Basins. When surface and/or groundwater come in contact with geologic strata containing sulfide minerals exposed by coal mining, the accelerated oxidation of sulfide minerals in the presence of ferric iron and/or oxygen can produce sulfuric acid. The process promotes the weathering of REE-bearing rocks and minerals in the host geologic strata. Compared to average river water and seawater, the concentrations of REEs can be orders of magnitude higher in CMD. In this study, we demonstrated a trap-extract-precipitate (TEP) process that can effectively recover REEs from CMD. The three-stage TEP process uses alkaline industrial by-products to capture REEs from CMD and then applies an extraction/precipitation procedure to produce a feedstock that can be economically processed to produce marketable rare earth oxides. The alkaline industrial by-products tested in this study include the residual from a water softening process (DRWP sludge) and two types of stabilized flue gas desulfurization materials (sFGDs). sFGD material is a mixture of lime (CaO) and two coal combustion by-products, calcium sulfite FGD by-product and fly ash. The objectives of this study are to (1) validate the effectiveness and feasibility; (2) determine mechanisms controlling the rare earth recovery, (3) quantify the associated economic and environmental benefits, and (4) evaluate the full-scale application. To achieve these objectives, tasks to be carried out in this proposed project are organized into three phases. In the first phase, the research team collaborated with Ohio Department of Natural Resources, American Electric Power, The Wilds (a nonprofit wildlife conservation organization), and a private landowner to carry out field investigations aimed to screen and evaluate the seasonal changes of rare earths in the CMD discharges that have high recovery potentials. Next, the recovery of REEs from CMD was tested using a series of lab-scale column and batch tests under, respectively, percolation and completely mixed conditions. Results obtained from these lab-scale studies show that all three tested solids are very effective in retaining REEs. Over 98% of the CMD REEs that contacted the solids were captured before the solids exhausted their neutralization capacities. We also determined an extraction process using a non-acid, organic ligand extraction solution that can effectively remobilize the retained REEs from the spent solids (over 90%). The REE concentrate (>7.5 wt. % of total REEs) is then formed in an aeration process. The TEP process uses environmentally benign industrial by-products and a naturally-occurring organic ligand to mitigate CMD and recover REEs. Techno-economic analysis (TEA) and life-cycle assessment (LCA) was carried out in the third phase. The engineering-economic costs and net energy, net CO2 emissions, and water and other requirements were investigated to understand the economic and environmental implications of this process. This work uses mass and energy balances from laboratory-scale experiments to estimate the economic costs and environmental impacts. The results suggest that passive treatment systems that use DRWP sludge are preferred over those that use sFGD material, because of lower economic costs ($89,300/yr with a unit cost of $86/gT-REE vs. $89,800/yr, or $278/gT-REE) and improved environmental performance across all indicators from two different impact assessment methods. These differences are largely attributable to the larger capacity of DRWP sludge in the passive treatment application. We envision this TEP process can be integrated with abandoned mine land (AML) reclamation to create an approach that can add economic incentives for AML reclamation, remediate CMD discharge, and eliminate public safety hazards and threats to local environment and ecological systems posed by AMLs. It can restore lands and communities that are adversely impacted by legacy mining.
This report describes our efforts to develop a partial electrochemical oxidation process to produce formaldehyde selectively from methanol. The effort examined numerous potential anode materials in pursuit of 70% Faradaic efficiency for conversion of methanol to formaldehyde. Among the various electrode materials tested herein both Pt and PtRu were identified as the most promising catalysts in this process as the Faradaic efficiency obtained in these cases are 40% and >70% respectively. Several other 3d transition metals, Pt group metals and their alloys were also studied in which the Faradaic efficiency was obtained within 5-30%. In case of Pt and PtRu bulk metal electrode shows higher selectivity to formaldehyde compared to their nanostructured materials. Based on the literature, nanostructured Pt and PtRu are considered as active catalysts for methanol fuel cells, thus, lower selectivity to formaldehyde with nano Pt and PtRu in our case was attributed to their preferential oxidation of methanol to CO 2 . Severe catalyst deactivation was noted when 0.5 (M) sulfuric acid was used as the electrolyte irrespective of catalyst formulation. On the other hand, much higher activity and selectivity for formaldehyde was noted when alkaline electrolyte was employed during oxidation. Considering selective electrochemical oxidation of methanol to formaldehyde is an area which is underexplored as of today, our findings about catalyst formulation and process condition is noteworthy in this direction. Both bulk metal electrodes of Pt and PtRu may be cost prohibitive and thus present challenges to the scale up this technology. Therefore, we recognize that additional efforts are needed to develop catalysts with high activities and Faradaic efficiencies similar to bulk electrodes for the electrooxidation of methanol to formaldehyde.
The ability to recover valuable trace level minerals from geothermal brines using high-performance solid-phase sorbents will be explored and developed. A compressive range of sorbent materials will be screened for application to metal extraction from geothermal brines. Preferred sorbents from extraction of trace levels of rare earths (REs), precious metals (PMs), and other critical/strategically valuable materials (CMs) such as Zn, Mn, Te, Sc, Se and U from geothermal brines will be identified. For the preferred sorbents PNNL will determine the volumes they are capable of providing efficient extraction from. The thermal and chemical limits (including, acid, sulfur, salt) for performance of the preferred sorbent materials will be determined; with a target of at least 125°C and perhaps as high as 400° C. Sorbent form factors (including, packed bed, membrane, mats) that can function efficiently and be installed cost effectively in geothermal energy plants will be assessed for chemical and economic viability. Material regeneration and cyclic utilization will be demonstrated, targeting hundreds to thousands of cycles. Options for recovery and purification (including, selective separation of heavy REs) of collected materials will be explored. A techno-economic analysis (TEA) will be performed to assess the best approach to provide a value-added extraction process for geothermal energy systems. The sorbent materials and engineering analysis will be applicable to other industrial processes in which secondary recovery of valuable materials could provide economic benefit.
Brewer’s spent grain (BSG), the main lignocellulosic by-product of the beer industry, represents an abundant yet underutilized resource with high potential for valorization. This study presents an integrated biorefinery approach to convert BSG into second-generation (2G) ethanol, bioactive vinasse for plant growth promotion, and fungal biomass as a potential mycoprotein source. The biomass was first subjected to biological delignification using the white-rot fungus Ganoderma lucidum, after which two valorization routes were explored: (i) evaluation of the fungal biomass as a mycoprotein candidate and (ii) alcoholic fermentation for ethanol production. For the latter, three pretreatment strategies were assessed (diluted sulfuric acid and two deep eutectic solvents (DESs) based on choline chloride combined with either glycerol or lactic acid) followed by a one-pot enzymatic saccharification and fermentation using Kluyveromyces marxianus SLP1. The highest ethanol yield on substrate (YP/S) was achieved with [Ch]Cl:lactic acid pretreatment (0.46 g/g, 89.32% of theoretical). Vinasse, recovered after distillation, was characterized for organic acid content and tested on Solanum lycopersicum seed germination, showing promising biostimulant activity. Overall, this work highlights the potential of BSG as a sustainable feedstock within circular economy models, enabling the production of multiple bio-based products from a single residue.
In this study, the corrosion behavior of laser-interference treated AA2024-T3 specimens, which are coated with a primer, is presented. The surface of as-received AA2024-T3 specimens were laser-interference structured by splitting the primary beam of a Q-switched Nd:YAG pulsed nanosecond laser into two beams and focusing them to the same spot on the specimen surface. After being stored in plastic cases for up to 70 d, without any additional cleaning, the specimens were spray painted with a chromate-containing epoxy primer, CA7233, compliant to MIL-PRF-23377 Type I Class C2 specification. The corrosion behavior of laser-interference specimens was assessed against that of specimens prepared by chromated conversion coating and sulfuric acid anodizing treatments. After the ASTM B117 corrosion exposure, it was found that the laser processed specimens exhibited only few blisters. On one hand, most specimens prepared at a laser fluence of 1.78 J/cm 2 , without any additional chemical cleaning, were found to develop one very small blister after only 96 h of exposure. However, the growth of these blisters was not significant even after 1,000 h of salt spray exposure. On the other hand, only a fraction of the specimens prepared at a laser fluence of 1.24 J/cm 2 and acetone wiped right after the laser structuring were found to develop several tiny blisters after 790 h and longer exposure. Overall, it was found that the corrosion damage was minimized at a laser rastering speed of 4 mm/s, a condition for which only 33% of specimens developed very minor corrosion damage. Furthermore, the ASTM D1654 creepage ratings, which was used to evaluate the corrosion damage along the scribe lines, were found to be at least nine for all coated panels. These results indicate that the laser-interference technique with the additional acetone wiping has the potential to be further developed as a nonchemical surface preparation technique for chromate-containing epoxy primers coating systems.