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At least 505 records · Page 28

Universal correlation for falling film evaporation heat transfer coefficients of water and seawater

Horizontal falling film evaporators are widely utilized in desalination industries to increase fresh water supply. However, universal correlations for seawater falling film evaporation under varied operational and geometrical conditions are simply unavailable in open literature. Thus, this study aims to develop such a universal correlation for both plain and enhanced tubes. The detailed heat transfer mechanisms are reviewed, and rational parameters are incorporated to develop the universal correlation. A dataset of 994 data points from 9 sources covering a wide range of conditions was compiled. These conditions include Reynolds numbers from 10 to 7235, heat fluxes from 7.7 to 208 kW/m -2 , saturation temperatures from 278 to 401 K, salinities from 0 to 60 gsalt kg -1 water, tube diameters from 15.8 to 50.8 mm, and liquid feeder height to diameter ratios from 1 to 2.25. Upon analysis, it was found that most of the recommended existing correlations exhibited poor predictive accuracy, as evidenced by larger MADs. The developed correlation in this study demonstrated the best predictive accuracy for the entire dataset, yielding a MAD of 16.8 % and an R 2 of 0.82. Furthermore, the performance of the new correlation was individually assessed across a broader spectrum of operational and design conditions, reflecting the individual conditions’ influences with an overall MAD of 20 %.

42 ENGINEERING↗

Design and synthesis of astatinated benzothiazole compounds for their potential use in Targeted Alpha Therapy (TAT) strategies to treat Alzheimer's disease-associated amyloid plaques

Alzheimer's disease (AD) is a terminal neurodegenerative disease characterized by the buildup of amyloid fibrils, amorphous aggregates and tauopathies. Several treatment modalities, which rely on various biological processes to reduce disease burden, have been largely ineffective at treating Alzheimer's disease. Targeted alpha therapy (TAT) has demonstrated positive results in the treatment of cancer. Benzothiazole derivatives have been successfully shown to target these plaques and are used in several imaging applications. One such derivative, Flutemetamol (Vizamyl TM ) is an FDA approved diagnostic tool for PET imaging of AD-associated plaques. We report the radiolabeling of benzothiazole derivatives with 211 At, a 7.2 h alpha emitting radionuclide, using a copper catalyzed reaction with a boronic acid precursor molecule. In conclusion, our final compound [ 211 At]3'-At-PIB-OMe had a radiochemical yield of 55% and was found to be stable for at least 3 h in phosphate buffered saline.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Harnessing dimethyl ether with ultra-low-grade heat for scaling-resistant brine concentration and fractional crystallization

Solvent-driven separations may enable scalable concentration of hypersaline brines, supporting a circular resource economy from the extraction of lithium and rare earth elements from spent battery and magnet leachates. This work analyses a novel solvent-driven water extraction (SDWE) system employing dimethyl ether (DME) and ultra-low-grade heat for brine concentration and fractional crystallization. SDWE exploits DME’s unique properties: (1) a low dielectric constant that promotes water solubility over charged solutes by a factor of 10 3 , and (2) a high volatility that facilitate efficient DME reconcentration with ultra-low-grade heat. The techno-economic viability of SDWE is assessed with a computational framework that encompasses a liquid–liquid separator and a solvent concentrator. We integrate the extended universal quasichemical model with the virial equation of state to predict the compositions of the complex three-phase DME-water mixture at vapor–liquid and liquid–liquid equilibrium. Subsequently, we optimize the thermodynamic and economic performance of SDWE, by controlling the interstage flash pressure, heat source temperature, and the number of concentrating stages. DME-based SDWE concentrates an input saline feed to 5.5 M and regenerates over 99 % of the DME using ultra-low-grade heat below 50 °C, with a DME/water selectivity ratio of 125. Here our calculations reveal that optimal performance is achieved at interstage flash pressures of 0.4 – 0.5 bar for heat source temperatures between 323–373 K, with improved exergetic efficiencies at lower temperatures. At a heat source temperature of 323 K and an interstage pressure of 0.489 bar, DME-driven SDWE achieves an optimal thermodynamic efficiency of 20.5 % and a projected specific cost of US$ 1.93 m -3 . These specific costs suggest that SDWE is competitive with commercialized thermal distillation technologies, while mitigating the traditional risks associated with scaling in heat and mass exchangers with hypersaline brines.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Molecular aspects of temperature swing solvent extraction for brine desalination using imidazole-based solvents

Solvent extraction desalination has shown to be a promising energy-efficient technique when compared to separation processes usually employed. Despite the remarkable impact of the organic solvent’s molecular characteristics on this process, few studies have been carried out so far to explicitly ascertain the influence of these characteristics on the solubility of water in the solvent. In this report we assess the viability of four different imidazole-based solvents and compare them to an amine compound for solvent extraction desalination of high salinity brines. All-atom molecular simulations of pure solvent and water-solvent bulk mixtures are used to ascertain the influence of the solvents’ molecular structures on solvent–solvent and solvent–water interaction. Our results show that water solubilization in imidazole-based solvents is an endothermic process, while for a secondary amine (diisopropylamine) it is an exothermic process. We show that imidazole-based solvents can be designed to provide characteristics favorable to brine desalination.

42 ENGINEERING↗

Mobilization of trace metals from caprock and formation rocks at the Illinois Basin – Decatur Project demonstration site under geological carbon dioxide sequestration conditions

One concern for geologic CO 2 sequestration is the potential leakage of CO 2 or CO 2 -saturated brine containing trace metals into overlying aquifers, which poses the risk of adversely affecting underground sources of drinking water. In this work, rock and brine samples collected in the Illinois Basin – Decatur Project (IBDP), a large-scale geological CO 2 sequestration demonstration project in Decatur, Illinois, USA, as well as synthetic brine samples were used to understand the mobilization of trace metals as a result of CO 2 –rock–brine interactions under IBDP-specific conditions (50 °C and 20.6 MPa). Rock sample characterization indicated that, at the IBDP site, trace metal concentrations were greatest in cap rock samples from the Eau Claire Formation, compared with those from formations above and below this Formation. The natural brine samples collected from the Mt. Simon Sandstone reservoir were highly reducing and saline, with trace metal concentrations up to 680 times greater than the U.S. Environmental Protection Agency-prescribed drinking water standards. Batch leaching experiments indicated that both trace metal mobilization from rock and immobilization from the brine occurred when high-pressure CO 2 was introduced into the rock-brine system. The amounts of metals mobilized from the rock generally accounted for <5% of the total metals in the rock, but for some metals, including Ni, Pb, and Tl, up to 63% of the metals in the rock were mobilized to the brine. Leaching of trace metals into synthetic brines was different from that into the natural brine. The results of this study provided current information on the trace element sources and will help in risk simulations and experimental design to further evaluate potential impact of leakage on groundwater quality, which is important for future GCS projects to consider for monitoring and containment assurance purposes.

58 GEOSCIENCES↗

Biomass and salt-dependent effects of Bacillus spores on radionuclide migration from the Waste Isolation Pilot Plant

Spores of a Bacillus sp., isolated from radioactive waste, were tested for their ability to influence the fate and transport of neodymium (Nd3+) under high salt conditions expected at the Waste Isolation Pilot Plant (WIPP) nuclear waste repository. Spores were suspended in neodymium-spiked saline solutions up to 4 M NaCl, and concentrations of Nd and the complexing agent dipicolinic acid (DPA), a component of spores, were monitored along with optical densities and spore numbers. Overall, results support neodymium bioassociation that is dependent upon biomass, with more apparent adsorption occurring at higher spore concentrations. However, probable spore lysis in 2 and 4 M NaCl solutions and possible germination at 0.15 M NaCl appear to drive the release of DPA and subsequent return of Nd to solution. The implications of this work for the WIPP will depend on actual biomass levels and the ionic strength of the repository brines.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Chemical impacts of subsurface CO 2 and brine on shallow groundwater quality

Leakage from geologic CO 2 sequestration (GCS) sites to overlying shallow drinking water aquifers is a tangible risk. A primary purpose of this study is to assess the potential impacts of CO 2 leakage into a fresh-water aquifer with associated CO 2 -water-sediment interactions. Here, the study site is the Ogallala aquifer overlying an active demonstration-scale GCS site in north Texas, USA. Using the results of combined batch experiments and reactive transport simulations, we discuss the effects of salinity on potential trace metal release and the potential for groundwater quality recovery after leakage ceases.

54 ENVIRONMENTAL SCIENCES↗

Evaluation of chromatographic resins for high efficacy separation of radium from chemical analogues

The separation of Radium (Ra) from interfering chemical analogues is of major importance for both the accurate measurement of Ra-226 in environmental samples and the preparation of radium targets destined for medical isotope production. The adsorption behavior of Ra, Barium (Ba), and Strontium (Sr) was investigated on multiple crown-ether-based proprietary extraction chromatographic resins developed by TrisKem Int. Among these, the TK101 resin, characterized by a novel room-temperature ionic liquid (RTIL) dual extractant–solvent system, demonstrated enhanced affinity and selectivity, particularly at low acid concentrations, achieving a D w of 3477 ± 73 for Ra in 0.04 M HNO₃, whereas the maximum Ra D w obtained with the traditional Sr resin in 8 M HNO 3 was only 12.33 ± 0.4. In 0.04 M HNO 3 , a Ra distribution ratio (D w ) of 776 was achieved within 1 min, indicating rapid uptake kinetics. The adsorption capacities were estimated at 19.6 ± 0.1 mg/g for Ba and 12.0 ± 0.2 mg/g for Sr. However, competing alkali metals significantly reduced alkaline earth metal uptake, indicating that the TK101 resin is best suited for radium purification following a preconcentration step to minimize matrix effects in high salinity samples. Dynamic column studies confirmed the strong chromatographic performance of the TK101 resin, with no significant Ba or Sr breakthrough in the Ra fraction and a Ra recovery of 87 ± 2.8%. These results demonstrate the potential of the TK101 resin for selective radium separation in analytical and radiochemical applications.

and nuclear chemistry↗

Exponential time differencing for the tracer equations appearing in primitive equation ocean models

The tracer equations are part of the primitive equations used in ocean modeling and describe the transport of tracers, such as temperature, salinity or chemicals, in the ocean. Depending on the number of tracers considered, several equations may be added to and coupled to the dynamics system. In many relevant situations, the time-step requirements of explicit methods imposed by the transport and mixing in the vertical direction are more restrictive than those for the horizontal, and this may cause the need to use very small time steps if a fully explicit method is employed. To overcome this issue, we propose an exponential time differencing (ETD) solver where the vertical terms (transport and diffusion) are treated with a matrix exponential, whereas the horizontal terms are dealt with in an explicit way. In this work, we investigate numerically the computational speed-ups that can be obtained over other semi-implicit methods, and we analyze the advantages of the method in the case of multiple tracers.

42 ENGINEERING↗

Molecular simulation of the structural and thermodynamic properties of n-alkane/brine interfacial systems with nonionic surfactants

All-atom molecular dynamics (MD) simulations are used to study the structural and thermodynamic properties of water + n-heptane interfacial systems in the presence of salinity (NaCl, NaI, KCl, and KI) and two different nonionic surfactants. Excellent qualitative and quantitative agreement with interfacial tension experimental data is obtained, but this requires applying a charge scaling factor to the ionic species, suggesting the likely role of polarizability effects. Tensoactive behavior is observed for the NaI and KI systems, coinciding with layering of the iodide species near the interface. Further, there are significant interaction differences between the surfactants and the different ionic species, but the structural and thermodynamic behavior of the surfactant molecules is relatively unaffected by the specific salt species. Our analysis suggest that the surfactant-surfactant interactions play a critical role in determining the interfacial behavior, with a much smaller impact associated with the composition of the brine phase.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Numerical study of the chemo-mechanical behavior of FEBEX bentonite in nuclear waste disposal based on the Barcelona expansive model

Experimental studies show that compacted bentonite used as a backfill material for nuclear waste repository experiences strong coupling between chemical and mechanical processes. Here, we use a dual-structure expansive soil model, referred to as the Barcelona Expansive Model (BExM), to predict the behavior of bentonite buffer in subsurface emplacement tunnels for high-level radioactive waste. After emplacement, the bentonite is subjected to complex and coupled Thermal-Hydraulic-Mechanical-Chemical (THMC) processes. The BExM constitutive model is implemented in a multi-phase reactive transport and geomechanics simulator, TOUGHREACT-FLAC3D, and the model is verified with one benchmark test on FEBEX bentonite. We utilize a one-way Chemo-Mechanical (C-M) coupling approach, in which chemical changes affect the mechanical behavior of bentonite through the BExM linked with the evolution of mass fraction of smectite, exchangeable cation concentration, and ionic strength via osmotic suction. The parameters of the new coupled model for FEBEX bentonite are calibrated against a series of laboratory experiments with various salinity solutions. Finally, coupled THMC modeling is conducted for a generic argillite repository with bentonite buffer under high temperature, focusing on the long-term chemical change and its effect on the mechanical process.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

CO2 partial pressure and fluxes in the Amazon River Plume using in situ and remote sensing data

Estimations of the global carbon budget include a quantitative understanding of the evolving processes that occur along river-to-ocean gradients. However, high spatiotemporal resolution observations of these processes are limited. Here we present in situ measurements of the partial pressure of CO2 (pCO2) made through the Amazon River plume (ARP) during different discharge seasons, from 2010-2012. We evaluated the spatiotemporal distribution of pCO2 using Soil Moisture and Ocean Salinity (SMOS) satellite observations for each hydrologic period in the ARP. Regression models were used to estimate pCO2 at the ARP for the period of 2010-2014. From these distributions we calculated sea-air gas exchange of CO2 between the plume waters and the atmosphere (F_co2^sea). Intra-annual variability of F_co2^sea was related to discharge at the river mouth and ocean currents as well as trade winds in the plume. Climatic events during the study period had a significant impact on the F_co2^sea. Including the plume area closer to the river mouth makes the ARP a net source of CO2 with an annual net sea-air flux of 8.6 ±7.1 Tg C y-1 from 2011-2014.

Amazon↗

Typological representation of the offshore oceanographic environment along the Alaskan North Slope

Erosion and flooding impacts to Arctic coastal environments are intensifying with nearshore oceanographic conditions acting as a key environmental driver. Robust and comprehensive assessment of the nearshore oceanographic conditions require knowledge of the following boundary conditions: incident wave energy, water level, incident wind energy, ocean temperature and salinity, bathymetry, and shoreline orientation. The number of offshore oceanographic boundary conditions can be large, requiring a significant computational investment to reproduce nearshore conditions. This present study develops location-independent typologies to reduce the number of boundary conditions needed to assess nearshore oceanographic environments in both a Historical (2007–2019) and Future (2020–2040) timespan along the Alaskan North Slope. We used WAVEWATCH III® and Delft3D Flexible Mesh model output from six oceanographic sites located along a constant ~50 m bathymetric line spanning the Chukchi to Beaufort Seas. K-means clustering was applied to the energy-weighted joint-probability distribution of significant wave height (H s ) and peak period (T p ). Distributions of wave and wind direction, wind speed, and water level associated with location-independent centroids were assigned single values to describe a reduced order, typological rendition of offshore oceanographic conditions. Reanalysis data (e.g., ASRv2, ERA5, and GOFS) grounded the historical simulations while projected conditions were obtained from downscaled GFDL-CM3 forced under RCP8.5 conditions. Location-dependence for each site is established through the occurrence joint-probability distribution in the form of unique scaling factors representing the fraction of time that the typology would occupy over a representative year. As anticipated, these typologies show increasingly energetic ocean conditions in the future. They also enable computationally efficient simulation of the nearshore oceanographic environment along the North Slope of Alaska for better characterization of coastal processes (e.g., erosion, flooding, or sediment transport).

54 ENVIRONMENTAL SCIENCES↗

Advanced supercritical water-based process concepts for treatment and beneficial reuse of brine in oil/gas production

Produced water generated from oil/gas reservoirs is a cost burden for oil/gas producers, with over 21 billion barrels of the waste generated in 2019. Average disposal costs range from 4.00–8.00·bbl -1 , with up to 20·bbl -1 spent on transportation alone. Dissolved solids content is a contributing factor which limits economical treatment options for this waste stream. This work proposes a novel technique that can handle high salinity waste, employing favorable properties past the critical point of water. In this study, process simulation of two supercritical water desalination (SCWD) scenarios was completed. Zero liquid discharge (ZLD) and brine concentration operating scenarios were compared, weighing the associated economics and benefits for each case. The results were shown to be economically feasible for brines with a high dissolved solids content, ranging from 3.49 to 17.28·bbl -1 in an expanded sensitivity analysis.

42 ENGINEERING↗

Application of electrodialysis pretreatment to enhance boron removal and reduce fouling during desalination by nanofiltration/reverse osmosis

we report membranes have emerged as promising technologies for treatment of non-traditional waters, but fouling and poor rejection of small, neutral solutes (e.g., boric acid) impede their further implementation for water purification. Boron rejection is increased by raising the pH to convert boric acid to borate ion, but this change often leads to calcite supersaturation. This study investigated the use of a hybrid electrodialysis-nanofiltration/reverse osmosis (ED-NF/RO) system to reduce fouling from calcite precipitation and calcium-polysaccharide sorption to NF/RO membranes. Also, the study examined the potential of the hybrid process to increase permeate flux and boron rejection during NF/RO of synthetic saline water. ED pretreatment reduced calcite oversaturation and reduced flux decline during NF/RO. Low alginate concentrations (25 mg/L) limited NF/RO fouling, but high concentrations (100 mg/L) appeared to promote calcite scaling. ED pretreatment reduced the osmotic pressure of the NF/RO feed water, enabling lower operating pressures or greater permeate water fluxes. Boron rejection during NF/RO increased with ED pretreatment, probably due to stronger electrostatic repulsion and an increase in the fraction of total boron present as B(OH)4- following ED. This hybrid ED-NF/RO system shows promise as a novel approach to enhancing the performance of current membrane systems for treating complex feed waters.

alginate↗

Computational and experimental study of different brines in temperature swing solvent extraction desalination with amine solvents

Rapid global urbanization and high-salinity wastewater disposal from industrial activities have exerted significant pressure on water resources. Over the past few years, temperature swing solvent extraction (TSSE) has been identified as a promising technique to desalinate hypersaline brines. Despite its potential, the TSSE desalination literature has been mainly based on empirical insights, and the limited molecular simulation studies have primarily focused on NaCl brines. Herein, we use molecular dynamics (MD) simulations to study the TSSE desalination of four different brines, namely, KCl, KBr, NaCl, and NaBr using diisopropylamine as the solvent. Based on both bulk and interfacial brine-diisopropylamine MD results, here we investigate the qualitative and quantitative performance of the simulations by benchmarking these results against our experimental evaluations of these same systems. MD results provide satisfactory qualitative agreement with the experimental data of water solubilization in the organic phase and amine solubilization in the aqueous phase for the KBr, KCl, and NaBr brines. Also, the molecular mechanism of solvation of ionic species by water molecules over diisopropylamine suggested by the MD simulations is in agreement with our experimental data. However, larger qualitative and quantitative deviations were observed for the NaCl brines, and this is likely due to polarization and charge transfer effects, as quantified by our quantum chemical calculations.

42 ENGINEERING↗

Co-treating flue gas desulfurized effluent and produced water enables novel waste management and recovery of critical minerals

Herein this study reports a novel approach of resource recovery from co-managing two geographically co-located and chemically complementary wastewaters using a pilot-scale treatment process. Designed to treat flue gas desulfurized (FGD) effluent from combustion powerplants and produced water (PW) from energy industries, the process consists of soda-ash softening, nanofiltration (NF), and reverse osmosis (RO). Recovered products are barite, calcite, and low-salinity water. Using field-collected waters, the results show that softening at pH 8.5 produces calcite (yield: 30 kg/m 3 treated water), a chemical used as SO ₂(g) scrubbers. NF treatment under an applied pressure of 3.5 MPa yields a permeate stream laden with monovalent ions (water recovery 60%) and a concentrate stream with a sulfate concentration 1.8 times of the feedwater concentration. Mixing the NF concentrate and PW at a volumetric ratio of 1.0 precipitates a high-density barite material (4.1 g/cm 3 , yield: ~7.5 kg/m 3 mixture) – a critical mineral commonly used as a weighting agent in drilling. The RO treatment recovers >64% water as the permeate, which can be readily used as cooling make-up water at the powerplants. The RO concentrate stream can be further processed in a thermal evaporative system for additional water recovery and brine production.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Supercritical water desalination and oxidation (SCWDO): Effectiveness on complex solutions, technoeconomic, and CO 2 impact for produced water treatment

The modern energy-economy is increasingly causing the production of highly saline brines, including from produced water. Supercritical water desalination can concentrate and extract minerals from these brines, but the effects of mixed salt interactions, organic degradation with additives, and the technology's economics are not well understood at supercritical condition. The present study evaluated and experimentally studied an integrated supercritical water desalination and oxidation (SCWDO) process for treating real-produced water samples from oil/natural gas field. The complex interactions between the various anions and cations in produced water were extensively evaluated. Most of the divalent and trivalent ions were extracted below 250 °C while the majority of the monovalent salt were removed between 380 to 410 °C. The treated real produced water was of drinking water quality, with <500 mg/l of total dissolved solid (TDS) and with 100% organics removal. Furthermore, the heat liberated during the organic oxidation could be utilized internally and for electricity generation for enhanced the energy efficiency and lower cost of produced water treatment. With system optimization, the proposed SCWDO process can essentially be made a net zero energy process. A novel process flow diagram for the commercial scale self-powered hybrid SCWDO technology was proposed as a cost-effective produced water treatment to mitigate the environmental crises. Techno-economic analysis showed that produced water treatment cost with SCWDO can be reduced to 2–3 $/m 3 and can be up to 60 % cheaper to traditional deep well reinjection. Additionally, the proposed SCWDO process could achieve net negative CO 2 emission.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗