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At least 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

New directions and principles for solvent extraction for recovery of lithium from aqueous brines and mineral leachates: A brief review

Increasing demand for lithium for manufacturing of batteries is fueling the unprecedented search for improved recovery and alternative sources. Wider source distribution, lower energy consumption, and greater sustainability make extraction of lithium from brines, both natural and process-derived, an attractive alternative to mineral ores. Solvent extraction, used industrially for production of metals, salts, and pharmaceuticals, has been investigated as a methodology for lithium recovery for several decades. However, industrial application of solvent extraction for lithium recovery has so far been limited. In contrast, direct lithium extraction using adsorbents based on inorganic minerals has rapidly advanced from research to commercialization. A comparison of solvent extraction processes to adsorption highlights these issues and explains the preference for adsorbents. Although the application of solvent extraction has been criticized for use of large amounts of acid, alkali, and organic solvents, steady progress has been made to improve its potential for industrial lithium production, spurred on generally by the advantages of solvent extraction in selectivity and throughput. Previously developed beta-diketone, organophosphate, and crown ether ligands are being adapted and improved. Their novel use with ionic liquids, deep eutectic solvents, and membrane technologies promises to expand capabilities for extraction of lithium from dilute aqueous sources while improving sustainability. Possibilities for further discovery and innovation abound. In this review, we provide a unique perspective from the field of solvent extraction starting with fundamentals such as ion-transfer theory and apply them to understanding lithium selectivity and extraction behavior. In conclusion, the results are cast in the light of the practical realities of developing economical solvent extraction processes.

Brine↗
DOE OSTI2013

Accelerated recovery of renal mitochondrial and tubule homeostasis with SIRT1/PGC-1α activation following ischemia–reperfusion injury

Kidney ischemia–reperfusion (I/R) injury elicits cellular injury in the proximal tubule, and mitochondrial dysfunction is a pathological consequence of I/R. Promoting mitochondrial biogenesis (MB) as a repair mechanism after injury may offer a unique strategy to restore both mitochondrial and organ function. Rats subjected to bilateral renal pedicle ligation for 22 min were treated once daily with the SIRT1 activator SRT1720 (5 mg/kg) starting 24 h after reperfusion until 72 h–144 h. SIRT1 expression was elevated in the renal cortex of rats after I/R + vehicle treatment (IRV), but was associated with less nuclear localization. SIRT1 expression was even further augmented and nuclear localization was restored in the kidneys of rats after I/R + SRT1720 treatment (IRS). PGC-1α was elevated at 72 h–144 h in IRV and IRS kidneys; however, SRT1720 treatment induced deacetylation of PGC-1α, a marker of activation. Mitochondrial proteins ATP synthase β, COX I, and NDUFB8, as well as mitochondrial respiration, were diminished 24 h–144 h in IRV rats, but were partially or fully restored in IRS rats. Urinary kidney injury molecule-1 (KIM-1) was persistently elevated in both IRV and IRS rats; however, KIM-1 tissue expression was attenuated in IRS rats. Additionally, sustained loss of Na{sup +},K{sup +}–ATPase expression and basolateral localization and elevated vimentin in IRV rats was normalized in IRS rats, suggesting restoration of a differentiated, polarized tubule epithelium. The results suggest that SRT1720 treatment expedited recovery of mitochondrial protein expression and function by enhancing MB, which was associated with faster proximal tubule repair. Targeting MB may offer unique therapeutic strategy following ischemic injury. - Highlights: • We examined recovery of mitochondrial and renal function after ischemia–reperfusion. • SRT1720 treatment after I/R induced mitochondrial biogenesis via SIRT1/PGC-1α. • Recovery of mitochondrial function was expedited with SRT1720 treatment. • Restoration of tubule homeostasis was expedited with SRT1720 treatment. • Activators of SIRT1 and PGC-1α may offer new therapeutic targets for AKI.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Emission assessment at the Burj Hammoud inactive municipal landfill: Viability of landfill gas recovery under the clean development mechanism

Highlights: Black-Right-Pointing-Pointer LFG emissions are measured at an abandoned landfill with highly organic waste. Black-Right-Pointing-Pointer Mean headspace and vent emissions are 0.240 and 0.074 l CH{sub 4}/m{sup 2} hr, respectively. Black-Right-Pointing-Pointer At sites with high food waste content, LFG generation drops rapidly after site closure. Black-Right-Pointing-Pointer The viability of LFG recovery for CDMs in developing countries is doubtful. - Abstract: This paper examines landfill gas (LFG) emissions at a large inactive waste disposal site to evaluate the viability of investment in LFG recovery through the clean development mechanism (CDM) initiative. For this purpose, field measurements of LFG emissions were conducted and the data were processed by geospatial interpolation to estimate an equivalent site emission rate which was used to calibrate and apply two LFG prediction models to forecast LFG emissions at the site. The mean CH{sub 4} flux values calculated through tessellation, inverse distance weighing and kriging were 0.188 {+-} 0.014, 0.224 {+-} 0.012 and 0.237 {+-} 0.008 l CH{sub 4}/m{sup 2} hr, respectively, compared to an arithmetic mean of 0.24 l/m{sup 2} hr. The flux values are within the reported range for closed landfills (0.06-0.89 l/m{sup 2} hr), and lower than the reported range for active landfills (0.42-2.46 l/m{sup 2} hr). Simulation results matched field measurements for low methane generation potential (L{sub 0}) values in the range of 19.8-102.6 m{sup 3}/ton of waste. LFG generation dropped rapidly to half its peak level only 4 yrs after landfill closure limiting the sustainability of LFG recovery systems in similar contexts and raising into doubt promoted CDM initiatives for similar waste.

09 BIOMASS FUELS↗
DOE OSTI2018

Environmental assessment of alternative treatment schemes for energy and nutrient recovery from livestock manure

Highlights: • Energy and nutrient recovery from manure was environmentally evaluated. • Direct digestate application is not always feasible. • AD+centrifugation+N-removal was the most environmentally favourable scenario. • N-removal through HRAS+PNA considerably improved the environmental performance. • UF membrane+acidification were needed to improve struvite quantity and quality. - Abstract: The application of livestock manure on agricultural land is being restricted due to its significant content of phosphorus (P) and nitrogen (N), leading to eutrophication. At the same time, the growing demand for N and P mineral fertilizers is increasing their production costs and causing the depletion of natural phosphate rock deposits. In the present work, seven technologically feasible treatment schemes for energy (biogas) and nutrient recovery (e.g., struvite precipitation) and/or removal (e.g., partial nitritation/anammox) were evaluated from an environmental perspective. In general, while approaches based solely on energy recovery and use of digestate as fertilizer are commonly limited by community regulations, strategies pursuing the generation of high-quality struvite are not environmentally sound alternatives. In contrast, schemes that include further solid/liquid separation of the digestate improved the environmental profile, and their combination with an additional N-removal stage would lead to the most environmental-friendly framework. However, the preferred scenario was identified to be highly dependent on the particular conditions of each site, integrating environmental, social and economic criteria.

09 BIOMASS FUELS↗
DOE OSTI2020

Continuous-Flow Centrifugal Solid/Liquid Separation for the Recovery of Rare-Earth Elements Containing Particles from Phosphoric Acid Sludge

Phosphoric acid sludge contains acid (~54% P 2 O 5 ) and solid precipitates including rare earth elements (REEs) at concentrations of ~2200 ppm. Low-cost recovery of valuable P 2 O 5 and simultaneous solid separation could be an economically feasible approach to recovering REEs while increasing the production of phosphoric acid. The sludge, however, is a complicated stream that cannot be separated by traditional technologies because of high viscosity and a large solid content (30–40%). Guided by a force balance model, an efficient solid/liquid separation method is demonstrated, using a continuous-flow centrifugal contactor. Additionally, the shear regime is bypassed by introducing the sludge directly into the rotor where a centrifugal force is exerted on the fluid, inducing phase separation. Solid particles are trapped in the contactor. High liquid recovery is demonstrated and the effects of process parameters on solid capture are investigated. Three contactors in series yield 94% recovery of solids containing 1500–2895 ppm of REEs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Doppler-resolved kinetics of saturation recovery

Frequency modulated laser transient absorption has been used to monitor the ground state rotational energy transfer rates of CN radicals in a double-resonance, depletion recovery experiment. When a pulsed laser is used to burn a hole in the equilibrium ground state population of one rotational state without velocity selection, the population recovery rate is found to depend strongly on the Doppler detuning of a narrow-band probe laser. Similar effects should be apparent for any relaxation rate process that competes effectively with velocity randomization. Alternative methods of extracting thermal rate constants in the presence of these non-thermal conditions are evaluated. Total recovery rate constants, analogous to total removal rate constants in an experiment preparing a single initial rotational level, are in good agreement with quantum scattering calculations, but are slower than previously reported experiments and show qualitatively different rotational state dependence between Ar and He collision partners. As a result, quasi-classical trajectory studies confirm that the differing rotational state dependence is primarily a kinematic effect.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Adsorption and Recovery of Polyphenolic Flavonoids Using TiO 2 -Functionalized Mesoporous Silica Nanoparticles

Exploiting specific interactions with titania (TiO 2 ) has been proposed for the separation and recovery of a broad range of biomolecules and natural products, including therapeutic polyphenolic flavonoids which are susceptible to degradation, such as quercetin. Functionalizing mesoporous silica with TiO 2 has many potential advantages over bulk and mesoporous TiO 2 as an adsorbent for natural products, including robust synthetic approaches leading to high surface area, stable separation platforms. Here, TiO 2 surface functionalized mesoporous silica nanoparticles (MSNPs) are synthesized and characterized as a function of TiO 2 content (up to 636 mg TiO2/g). The adsorption isotherms of two polyphenolic flavonoids, quercetin and rutin, were determined (0.05-10 mg/ml in ethanol), and a 100-fold increase in the adsorption capacity was observed relative to functionalized nonporous particles with similar TiO 2 surface coverage. An optimum extent of functionalization (approximately 440 mg TiO 2 /g particles) is interpreted from characterization techniques including grazing incidence x-ray scattering (GIXS), high resolution transmission electron microscopy (HRTEM) and nitrogen adsorption, which examined the interplay between the extent of TiO 2 functionalization and the accessibility of the porous structures. The recovery of flavonoids is demonstrated using ligand displacement in ethanolic citric acid solution (20% w/v), in which greater than 90% recovery can be achieved in a multistep extraction process. The radical scavenging activity (RSA) of the recovered and particle-bound quercetin as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay demonstrates greater than 80% retention of antioxidant activity by both particle-bound and recovered quercetin. In conclusion, these mesoporous titanosilicate materials can serve as a synthetic platform to isolate, recover, and potentially deliver degradation-sensitive natural products to biological systems.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Anaerobic Dynamic Membrane Bioreactor Development to Facilitate Organic Waste Conversion to Medium-Chain Carboxylic Acids and Their Downstream Recovery

Platform chemicals such as medium-chain carboxylic acids (MCCAs) can be produced from organic waste streams via chain elongation in anaerobic mixed-culture bioreactors. A product recovery system is needed to collect MCCAs from the bioreactor effluent. Membrane-based liquid–liquid extraction, the most commonly used product recovery approach, requires suspended solids removal from the bioreactor effluent to avoid membrane fouling. An anaerobic dynamic membrane bioreactor (AnDMBR) was developed to evaluate MCCA production from brewery and prefermented food waste and to produce a permeate with low suspended solids to facilitate downstream product recovery. The AnDMBR employed an inexpensive stainless-steel mesh as the support material for the development of a biofilm or dynamic membrane, which was responsible for solids–liquid separation. The AnDMBR produced a permeate quality with an average total suspended solids (TSS) concentration of 0.12 g L –1 , while the average bioreactor TSS concentration was two orders of magnitude higher (21.6 g L –1 ). A maximum solids removal efficiency of ≥99% was achieved and good permeate quality was sustained for over 200 days without fouling control or cleaning the support material. In addition to solids–liquid separation, the dynamic membrane was responsible for a substantial fraction of the biological activity of the AnDMBR. The relative activity of Clostridiales, as determined by 16S rRNA sequencing, correlated with MCCA production and was higher in the dynamic membrane (20.0 ± 4.9%) than in the suspended biomass (5.2 ± 2.7%) in the bioreactor. This observation was consistent with MCCA production data as the permeate MCCA concentrations were significantly (p = 8.2 × 10 –5 ) higher than that in the bioreactor, suggesting that the dynamic membrane biofilm contributed to chain elongation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Development of an Energy-Efficient and High-Productivity Ammonia Recovery and Removal Process Using Resin-Wafer Electrodeionization

As efforts to develop various energy resources, ammonia energy is emerging as a promising carbon-free fuel alternative. Recovering high-concentration ammonia and ammonium from wastewater potentially offers significant environmental and economic benefits. However, research on recovery technologies for industries such as semiconductors remains limited. This study develops an efficient, energy-saving ammonia recovery technology using Resin Wafer Electrodeionization (RW-EDI), specifically for the semiconductor industry. RW-EDI shows promise for recovering ammonia from high-concentration wastewater. By optimizing parameters, such as voltage and initial concentration, a balance between productivity and energy consumption is achieved. Results indicate that ammonium and fluoride ion transport kinetics are similar, with minimal competition and selectivity values between 0.95 and 1.08. As the initial ammonia/ammonium concentration increases from 500 to 8000 ppm, reaction rate constants and the overall mass transfer coefficient decrease. Increasing the voltage can enhance mass transfer and eliminate barriers. Ion transport primarily occurs in the RW solid phase, accounting for 93.89% of the total current. Additionally, RW-EDI shows superior specific energy consumption within a concentration range of 500 ppm to 8000 ppm, outperforming technologies like electrodialysis by reducing specific energy consumption from 8−15 kWh/kg-NH 4 + to 1.2−2.5 kWh/kg-NH 4 + . This study highlights RW-EDI’s potential for ammonia recovery, providing valuable insights for future applications in wastewater treatment.

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

Decadal-scale recovery of carbon stocks after wildfires throughout the boreal forests

Boreal forests store 30% of the world's terrestrial carbon (C). Consequently, climate change mediated alterations in the boreal forest fire regime can have a significant impact on the global C budget. Here, we synthesize the effects of forest fires on the stocks and recovery rates of C in boreal forests from 368 plots from 16 long-term (= 100 years) fire chronosequences spread throughout the boreal zone. The mean annual temperature varied from -9.5°C to +5.2°C and annual precipitation from 295 mm to 824 mm in the study sites. Total C stocks decreased on average by 60% (range from <10% to >80%) because of forest fires, primarily due to large declines in the living trees and O-layer C stocks. C emissions of fires ranged from 0.1 to 11.4 kg m-2, and in most cases, the emissions were < 4 kg m-2. Total C stocks increased with time since fire following a sigmoidal shape Gompertz function, and it took 125 years until an average asymptote of 8.1 kg C m-2 was reached. Total C stocks accumulated at a rate of 2–60 g m-2 yr-1 during the first 100 years. We found that potential evapotranspiration (PET) was significantly correlated with C stocks and their post-fire recovery, likely because it integrates temperature, radiation and the length of the growing season. If the fire return interval shortens to under 100 years in the future, this suggests that many boreal forests will be prevented from reaching their full C storage potential. However, our results suggest that climate warming-induced increases in PET may also speed up the post-fire recovery of C stocks.

carbon accumulation, carbon pools, chronosequence,↗
DOE OSTI2026

Asymmetric pathways for lithium extraction and recovery based on the two-phase equilibrium of layered oxides

Electrochemical intercalation offers a promising platform for Li + extraction. However, only limited types of electrode materials have been investigated. The challenge to broaden and tailor materials for electrochemical intercalation-based Li + extraction lies in the lack of understanding of material’s response upon co-intercalation of multiple ions, therefore, paired process design to enable reversible Li + extraction and recovery. Here, we showcase the design of asymmetric ion pathways for Li + extraction and recovery for host material with complex Li + and Na + interaction using layered cobalt oxide as a model material. The two-phase equilibrium of Na 0.48 CoO 2 and Li 0.94 CoO 2 governs Li + selectivity when a high depth of intercalation is achieved (low vacancy level). We show that the relative rate between ion exchange and intercalation is critical to determine the ion pathways. The relationship can be quantitatively compared using the average pseudo ion exchange rate (C pseudoIX ) and the intercalation rate (C inter ). The ion pathways at the three regimes with C pseudoIX > C inter , C pseudoIX ~ C inter , and C pseudoIX < C inter are constructed. By selecting the optimized ion pathway and particle size, we demonstrate 9.7×10 4 Li + selectivity with 99% purity Li + recovery from an initial 1:1000 Li: Na molar ratio solution using 115 mAh/g specific capacity.

electrochemistry↗
DOE OSTI2018

Sparse recovery of undersampled intensity patterns for coherent diffraction imaging at high X-ray energies

Coherent X-ray photons with energies higher than 50 keV offer new possibilities for imaging nanoscale lattice distortions in bulk crystalline materials using Bragg peak phase retrieval methods. However, the compression of reciprocal space at high energies typically results in poorly resolved fringes on an area detector, rendering the diffraction data unsuitable for the three-dimensional reconstruction of compact crystals. To address this problem, we propose a method by which to recover fine fringe detail in the scattered intensity. This recovery is achieved in two steps: multiple undersampled measurements are made by in-plane sub-pixel motion of the area detector, then this data set is passed to a sparsity-based numerical solver that recovers fringe detail suitable for standard Bragg coherent diffraction imaging (BCDI) reconstruction methods of compact single crystals. The key insight of this paper is that sparsity in a BCDI data set can be enforced by recognising that the signal in the detector, though poorly resolved, is band-limited. This requires fewer in-plane detector translations for complete signal recovery, while adhering to information theory limits. Lastly, we use simulated BCDI data sets to demonstrate the approach, outline our sparse recovery strategy, and comment on future opportunities.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Efficient Sn Recovery from SnO 2 by Alkane (C x H y=2x+2 , 0 ≤ x ≤ 4) Reduction

We study the mechanism of alkane reduction of SnO 2 for efficient low-temperature recovery of Sn from SnO 2 . Based on thermodynamic simulation results, we comparatively analyze the reduction behavior and the efficiency of SnO 2 reduction by H 2 and alkanes (C x H y=2x+2 , 0 ≤ x ≤ 4). We found that alkanes (n·C x H y ) with the higher nx generally complete the reduction of SnO 2 (T 100 ) at the lower temperature. Moreover, the T 100 of the SnO 2 reduction by alkanes (n·C x H y ) was decreased from the T 100 of pure hydrogen with the same amount of hydrogen atoms (n·H y ). We found that the concentration of a gas phase product mixture, the amount of the produced solid carbon, and the T 100 complementary vary as a function of the nx and ny, the total amount of carbon and hydrogen atoms in the reducing gas phase molecules. Our results demonstrate a viability of the low temperature reduction method of SnO 2 by alkanes for efficient recovery of Sn from SnO 2 , which can be applied for Sn recovery from Sn containing industrial wastes or Sn ores with economic value added that is held by the co-produced H 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Faster recovery of North Atlantic tropical cyclone-induced cold wakes in recent decades

Intense winds associated with tropical cyclones (TCs) generate surface ocean cooling in their wakes, which can persist for several weeks in their aftermath. While multi-decadal observations of the sea surface have shown a substantial warming of the ocean, long-term changes in cold wake recovery time remain largely unknown. Here we find a trend toward faster recovery of TC cold wakes in the Atlantic main development region (MDR) since 2001. This is due primarily to a decrease in the strength of the North Atlantic trade winds, which reduces evaporative cooling of the ocean. The faster damping of TC cold wakes has led to a significant increase in the intensification of subsequent TCs that encounter lingering wakes from prior TCs, with a magnitude that is about 9% of that from long-term warming of the ocean. Finally, earth system model simulations indicate that the observed decrease in the cold wake recovery time will likely continue into the future.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Reduced methane recovery at high pressure due to methane trapping in shale nanopores

By 2050, shale gas production is expected to exceed three-quarters of total US natural gas production. However, current unconventional hydrocarbon gas recovery rates are only around 20%. Maximizing production of this natural resource thus necessitates improved understanding of the fundamental mechanisms underlying hydrocarbon retention within the nanoporous shale matrix. In this study, we integrated molecular simulation with high-pressure small-angle neutron scattering (SANS), an experimental technique uniquely capable of characterizing methane behavior in situ within shale nanopores at elevated pressures. Samples were created using Marcellus shale, a gas-generative formation comprising the largest natural gas field in the United States. Our results demonstrate that, contrary to the conventional wisdom that elevated drawdown pressure increases methane recovery, a higher peak pressure led to the trapping of dense, liquid-like methane in sub-2 nm radius nanopores, which comprise more than 90% of the measured nanopore volume, due to irreversible deformation of the kerogen matrix. These findings have critical implications for pressure management strategies to maximize hydrocarbon recovery, as well as broad implications for fluid behavior under confinement.

58 GEOSCIENCES↗
DOE OSTI2022

Microbial contribution to post-fire tundra ecosystem recovery over the 21st century

Abstract Tundra ecosystems have experienced an increased frequency of fire, and this trend is predicted to continue throughout the 21 st Century. Post-fire recovery is underpinned by complex interactions between microbial functional groups that drive nutrient cycling. Here we use a mechanistic model to demonstrate an acceleration of the nitrogen cycle post-fire driven by changes in niche space and microbial competitive dynamics. We show that over the first 5-years post-fire, fast-growing bacterial heterotrophs colonize regions of the soil previously occupied by slower-growing saprotrophic fungi. The bacterial heterotrophs mineralize organic matter, releasing nutrients into the soil. This pathway outweighs new sources of nitrogen and facilitates the recovery of plant productivity. We broadly show here that while consideration of distinct microbial metabolisms related to carbon and nutrient cycling remains rare in terrestrial ecosystem models, they are important when considering the rate of ecosystem recovery post-disturbance and the feedback to soil nutrient cycles on centennial timescales.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Production and distillative recovery of valuable lignin-derived products from biocrude

Value-added chemicals present in liquid products from direct liquefaction of biomass can be recovered as bioproducts in an integrated biorefinery to enhance the economic viability of biomass-to-liquid fuel technologies and afford a higher return on investment. In recent efforts, RTI International is exploring and developing processes that could be used to produce bioproducts in addition to liquid fuel from biocrude intermediates. The present study focused on the production and recovery of high-value lignin-derived compounds from biocrude. Catalytic pyrolysis with a nonzeolite, alumina-based catalyst was used to produce the biocrude from loblolly pine in RTI's 1-tonne per day pilot-scale plant. Distillation was evaluated as a potential separation method given that the biocrude is relatively thermally stable and distillable compared to raw pyrolysis oils. The distillation studies were performed with a laboratory distillation unit (PETRODIST 300 CC) and the biocrude was fractionated into four distillate cuts: cut 1 (IBP-110 °C), cut 2 (110–200 °C), cut 3 (200–300 °C), and cut 4 (300–400 °C). In a case study, cut 3 was distilled further to concentrate the lignin-derived chemicals boiling between 200 and 270 °C. The results showed that a biocrude containing about 10 wt% guaiacols could be concentrated to about 35 wt% of guaiacols (representing 75% recovery) in the first distillation step. The second distillation step increased the concentration of guaiacols to about 53 wt% (representing 80% recovery). Furthermore, these findings suggest that it is possible to isolate and concentrate the lignin-derived products using a distillation column with a number of plates/trays. The yields, physicochemical properties, and chemical composition of the fractions, as well as the overall distillation separation efficiency, are reported.

09 BIOMASS FUELS↗
DOE OSTI2019

Energy recovery in capacitive deionization systems with inverted operation characteristics

Capacitive deionization (CDI) operated under inverted mode involves electronic charging and discharge steps with corresponding ion concentration and desalting coupled with simultaneous energy storage. In this work, an energy recovery system derived from a Cuk dc–dc converter is explored to transfer the energy stored from one inverted capacitive deionization (i-CDI) cell during the electronic discharge step to another during the charge step, decreasing the overall energy requirement for capacitive water desalination. The i-CDI cell, a subset of CDI architecture operated in an inverted mode, is improved by incorporating ion-selective membranes to allow inverted membrane capacitive deionization (i-MCDI), leading to enhanced charge storage achieved with reduced energy input. For example, in comparison to i-CDI that requires ~12 J g -1 of energy input, the i-MCDI cell requires only 8 J g -1 . By incorporating the recovery system, the energy penalty can be reduced to only require ~8 and 4 J g -1 for i-CDI and i-MCDI cells, respectively. Improvement in energy recovery was shown to be achieved by reducing charge leakage, with the i-MCDI cell showing up to 3 times the leakage resistance of the i-CDI cell.

54 ENVIRONMENTAL SCIENCES↗