Search Results (365)

Selective ion transport is essential for many applications of membrane separation, such as rare metal and high-value element extraction from complex ionic sources. However, efficient regulation of permeability–selectivity remains a major challenge for advanced ionic transport membranes. Herein, we demonstrate that supercritical CO₂ (ScCO₂) drying combined with crown ether functionalization enables precise modulation of crystallinity and ion-specific affinity in covalent organic framework (COF) membranes. The pristine COF membrane prepared by solution casting was amorphous. Owing to its positively charged framework and sub-nanometer pores, the membrane exhibited a high Li⁺ transport rate over Mg²⁺ via a synergistic effect of size exclusion and electrostatic repulsion, resulting in a selectivity of 204. After ScCO₂ drying, the crystallinity and structural ordering of the COF membrane were significantly enhanced, leading to a 1.5-fold increase in Li⁺ flux, accompanied by a moderate decrease in selectivity to 147. To compensate for this trade-off, 12-crown-4 (12C4) was introduced as a Li⁺ recognition agent into the ScCO₂-treated membrane, restoring Li⁺/Mg²⁺ selectivity to 187 without compromising Li⁺ flux. Importantly, the selective Li⁺ transport performance was maintained in real salt lake brines. This structural–chemical co-regulation strategy provides a versatile approach for optimizing ion transport membranes in complex separation applications. Full article

Geologic carbon storage (GCS) is expanding rapidly as a cornerstone decarbonization option, but its climate value depends on maintaining long-term containment of CO₂ and displaced formation brine. Legacy wells—many drilled and abandoned before modern barrier standards—remain one of the most credible and controllable pathways for unintended upward migration. To support transparent, fit-for-purpose risk screening, this study benchmarks three leakage-modeling philosophies across a common six-layer scenario: (i) a reservoir-scale analytical solution for layered aquifers, (ii) a semi-analytical pressure-transient model that captures rock–fluid compressibility and breakthrough time, and (iii) a new mechanistic wellbore-scale model that explicitly represents dominant annular failure pathways (micro-annuli, cement fractures, casing breaches, and cement–formation interface flow) with pathway-specific hydraulic losses. Results show that model choice and physics assumptions drive order-of-magnitude differences in predicted brine rates: after 1000 days, the analytical model predicts ~1.7 bbls/day, the pressure-transient model exceeds 8 bbls/day, whereas the mechanistic model yields damage-dependent outcomes (~0.2–0.4 bbls/day for moderate–severe cement damage and up to ~3.5 bbls/day for open-channel conditions). These findings demonstrate that neglecting wellbore hydraulic resistance can systematically overstate leakage risk, while mechanistic pathway representation enables more realistic, condition-dependent screening. Future work will focus on model calibration to field/monitoring data, probabilistic parameterization of defect geometries, and extension to multiphase/reactive leakage to support operational decision-making and regulatory assurance. Full article

The increasing global demand for energy has accelerated the depletion of identified conventional resources, highlighting the need for sustainable alternatives. Geothermal energy, a renewable resource derived from the Earth’s internal heat, offers a reliable solution for both power generation and direct use applications. We present a comprehensive investigation of medium-enthalpy geothermal reservoirs in the Prinos–Kavala Basin, Northern Aegean, Greece. We firstly integrate geological, geophysical, and geochemical data from 66 wells across Prinos–Kavala basin to analyze the temperature distribution in the reservoir. The methodology includes the correction of bottom-hole temperatures and estimation of the geothermal gradients. A 1-D semi-steady-state well temperature modeling technique was applied to estimate the expected production wellhead temperature and assess its suitability for surface heating applications. Results reveal significant spatial heterogeneity in geothermal gradients and reservoir properties, with overpressured conditions confirmed in key zones. The integration of 3D reservoir model and isothermal mapping (>90 °C) identifies zones with high geothermal potential, supporting optimal exploitation strategies. The estimated production wellhead temperatures support the utilization of the produced brine heat content for various applications, among them the pre-heating of a CO₂ stream to be injected within the CCS framework for wellbore thermal stress management purposes. The findings demonstrate the value of reservoir characterization for sustainable geothermal development in complex tectonic settings. Full article

Bromine, as a strategic fundamental chemical raw material, is crucial for modern industry, but the traditional chlorine displacement method poses safety risks in oilfield brine development and faces challenges like resource depletion and inefficient utilization. Addressing the need for high-concentration bromine brine development in underground oilfields, this study developed an electrochemical oxidation-based chlorine-free bromine extraction technology. Leveraging the standard redox potential difference between Br⁻ and Cl⁻ (0.271 V), the effective potential window for selective Br⁻ oxidation was determined as 1.0–1.52 V (vs. SHE) via linear sweep voltammetry (LSV). Within this window, efficient and preferential oxidation of Br⁻ over Cl⁻ and OH⁻ was achieved. In simulated brine with high chloride and low bromide concentrations, a Br⁻ conversion rate of 92.3% was attained with no Cl₂ generation. The self-designed zero-gap electrolyzer with carbon cloth as the anode reduced the reaction time by over 75% compared to a traditional H-type cell, oxidizing over 90% of Br⁻ within 12 min. Kinetic studies revealed that the reaction follows first-order kinetics, with current intensity positively correlated with Br⁻ concentration. Investigation of coexisting ions revealed that low concentrations of Cl⁻ promote the reaction, while high concentrations exert inhibitory effects. CO₃²⁻ exhibits a weak promoting effect, and Ca²⁺/Mg²⁺ show negligible impact. Notably, organic matter (e.g., ethylene glycol) concentrations exceeding 80 mg/L substantially compromise bromine recovery efficiency. This technology provides a feasible solution for the safe and green development of high-concentration bromine resources and holds significant importance for the upgrading of the bromine chemical industry. Full article

High salinity and hardness in flowback fluids from tight reservoirs severely degrade the performance of conventional fracturing fluids, leading to formation damage and imposing major constraints on water recycling. An innovative in situ molecular interface regulation strategy that bypasses the need for costly pretreatment was proposed. A novel zwitterionic polymer was synthesized by grafting trimethylamine N-oxide (TMAO) onto hydrolyzed polyacrylamide. This hydrolyzed polyacrylamide grafted with trimethylamine N-oxide polymer (HPAMT) leverages zwitterionic TMAO groups to form a robust hydration layer approximately 0.25 nm thick on the polymer chains. Each TMAO group can immobilize up to 22.2 water molecules, effectively shielding the polymer from the detrimental effects of ions like Ca²⁺ and Na⁺, thereby preventing chain curling and preserving cross-linking sites. Experimental results demonstrate that HPAMT fracturing fluid prepared with untreated flowback fluids retains over 70% of its initial viscosity. The HPAMT fracturing fluid exhibits superior thermal and shear stability, maintaining more than 90% viscosity after exposure to 90 °C and the shear rate of 170 s⁻¹ for 60 min. Furthermore, HPAMT provides excellent proppant suspension, exceeding 60 min of static settling time. The broken gel viscosity remains below 5 mPa·s, enabling the direct reuse of flowback water. This technology overcomes the critical compatibility issue between traditional polymers and challenging brine chemistry, significantly reducing freshwater consumption and operational costs, thus presenting a viable and innovative solution for enhancing the environmental sustainability of unconventional resource development. Full article

In response to the environmental and health concerns associated with high-sodium brine disposal and the sodium content in table olives, this study proposes a novel, sustainable preservation method that completely replaces traditional brine with chitosan solutions. Three food-grade chitosan solutions were formulated using acetic acid, vinegar, and vinegar neutralized with baking soda as alternative liquid media for preserving Kalamata olives. Over a five-month storage period with a one-year endpoint, these solutions were evaluated against a conventional 8% NaCl brine control. The chitosan-based systems demonstrated effective microbial control, maintaining significantly lower total viable counts for most of the storage period, while yeast and mold populations were comparable to or slightly higher than the control over extended storage. Notably, they reduced the medium’s salinity by 75–85%, directly addressing the issue of high sodium content. The chitosan solutions also provided superior pH stability and color maintenance in the olives. A key finding was the distinct nature of the interaction between the olives and the chitosan medium compared to brine: while antioxidant activity within the olive flesh declined, the chitosan solutions themselves exhibited high and stable intrinsic antioxidant capacity (>78%), acting as an active antioxidant reservoir—a dynamic not observed with traditional brine. This research successfully validates chitosan solution as a viable, low-sodium, brine-free preservation medium, offering a novel strategy for sustainable olive processing that valorizes seafood waste and aligns with circular economy principles. Full article

With the increasing depletion of shallow resources, marine-based mineral resources in coastal and continental shelf areas are poised to become a new frontier for resource development. However, ions in brine solutions undergo complex water-rock interactions with rocks, affecting the engineering stability of marine-based rock masses. This study addresses engineering safety concerns arising from the long-term coupled effects of brine erosion and confining pressure on rocks during seabed mineral resource extraction. Using red sandstone as the research subject, it investigates the evolution of its mechanical properties under complex brine-erosion conditions. Experiments involved immersing red sandstone specimens in simulated seabed brine solutions for erosion cycles of 14, 21, and 35 days. Triaxial compression tests were conducted under confining pressures of 5 MPa, 10 MPa, and 15 MPa to systematically analyze the effects of erosion duration and confining pressure on rock strength, deformation, energy characteristics, and failure modes. Results indicate that brine erosion significantly reduces the strength and elastic modulus of red sandstone, but the effect is not simply linear. Instead, it follows a trend of initial slight strengthening followed by significant deterioration. During short-term erosion (21 days), some mechanical parameters slightly recovered, potentially due to temporary filling of fractures by brine ions. After long-term erosion (35 days), all mechanical properties markedly declined. This study aims to reveal the triaxial mechanical properties and energy evolution patterns of red sandstone under multi-ionic brine erosion, providing crucial experimental evidence for designing safe isolation layers and evaluating long-term stability in seabed mining. Full article

Formate solutions are widely used as completion, workover, and kill fluids; however, in multisolute systems, conventional experimental approaches struggle to efficiently identify formulations that simultaneously satisfy target density requirements and minimize formulation cost. To address this challenge, a data-driven optimization framework based on regression modeling was developed to determine minimum-cost formate formulations under specified density constraints. Seven solution systems comprising sodium formate, potassium formate, and cesium formate in single-solute, binary-solute, and ternary-solute combinations were investigated at 20 °C, using 70 data sets collected from the literature and laboratory experiments. The solute-to-solvent mass ratio (SSMR) was introduced as the key formulation variable to construct solution density prediction models, and a cost-based objective function was established to inversely calculate optimal SSMR combinations. Model predictions were validated against laboratory measurements, showing mean density errors ranging from 0.022 to 0.145 g/cm³ across the seven systems, with an overall RMSE of 0.094 g/cm³ and MAE of 0.070 g/cm³. The results demonstrate that the proposed data-driven optimization method enables accurate density prediction and cost-efficient formulation design, providing a practical and scalable alternative to traditional trial-and-error experimental methods for wellbore working-fluid optimization. Full article

The deep brine reservoirs in the Jianshishan area of the Qaidam Basin are abundant in strategic mineral resources. Traditional extraction methods suffer from insufficient reservoir energy and low recovery efficiency, while CO₂ flooding technology offers a new solution integrating brine development and CO₂ sequestration. However, the reservoir comprises three typical lithologies (calcareous mudstone, laminated mudstone, and massive sandstone) with distinct mineral compositions and structural characteristics and the mechanisms by which CO₂–brine–reservoir reactions affect their pore structures remain unclear. This study conducted laboratory simulation experiments combined with multiple analytical techniques to investigate the evolutionary characteristics of the three lithologies under CO₂ action. The results show that (1) calcareous mudstone has the strongest dissolution effect, with porosity increasing from 6.25% to 9.29% (an increase of 48.6%) and permeability increasing from 0.0012 mD to 0.0511 mD (an increase of 41.6 times); (2) laminated mudstone shows a trend of “first improvement, then deterioration”, with porosity initially rising to 11.84% and then slightly decreasing, and permeability decreasing from 0.0042 mD to 0.0036 mD; and (3) massive sandstone has stable mineral composition, with porosity increasing from 10.74% to 11.63% (an increase of 8.3%) and permeability fluctuating slightly between 0.0028 and 0.0032 mD. This study reveals that lithological mineral composition and structural characteristics are core factors controlling pore structure evolution, providing theoretical and experimental support for optimizing differentiated CO₂ flooding schemes for deep brine reservoirs. Full article

Oxidative stress contributes significantly to chronic disease burden, necessitating identification of accessible dietary antioxidant sources. Pigeon peas (Cajanus cajan L.) contain substantial bioactive compounds, yet most exist in bound forms with limited bioavailability. This study evaluated wild fermentation combined with systematic extraction optimization to enhance antioxidant recovery from pigeon peas. Seeds underwent wild fermentation in brine solution, followed by extraction under varying conditions (seven solvent systems, three temperatures, and three-time durations). Multiple complementary assays assessed antioxidant capacity (total phenolic content, DPPH radical scavenging, ferric reducing power, and ABTS activity). Fermentation substantially improved antioxidant properties across all parameters, with particularly pronounced effects on radical scavenging activities. Extraction optimization identified 70% methanol at 40 °C for 24 h as optimal, demonstrating marked improvements over conventional protocols. Strong intercorrelations among assays confirmed coordinated enhancement of multiple antioxidant mechanisms rather than isolated changes. The findings demonstrate that both biotechnological processing and analytical methodology critically influence antioxidant characterization in pigeon peas. This integrated approach offers practical guidance for developing antioxidant-rich functional foods, particularly relevant for resource-limited settings where pigeon peas serve as dietary staples. The study establishes foundation for translating fermentation technology into nutritional interventions, though further research addressing bioavailability, microbiological characterization, and bioactive compound identification remains essential. Full article

Sodium chloride is a chemical compound that humans use in large quantities, both for consumption and for applications in many areas. This article aims to present various aspects of salt: production, health, tourism, cultural, environmental, and finally, historical. It mainly discusses the operation of the brine graduation towers—the last ones preserved in the technological line at the salt production plant. The authors aimed to illustrate the advantages and challenges associated with salt and to present solutions to the existing problems. Full article

The increasing demand for lithium in energy storage technologies has renewed interest in clay-type deposits as alternative resources to brines and hard rock ores. This study investigates the leaching behavior of a Mexican clay-type lithium ore through conventional, hot, and pressure leaching using sulfuric acid. Mineralogical characterization (XRD and SEM–EDS) revealed that montmorillonite (~56 wt.%) is the primary lithium-bearing phase. Conventional leaching with 1–8 M H₂SO₄ resulted in limited lithium dissolution (<30% after 24 h), whereas hot leaching at 80 °C increased extraction to ~39%. Pressure leaching with oxygen overpressure significantly enhanced lithium dissolution, achieving ~64% within 180 min under 8 M H₂SO₄ and 80 °C. Kinetic modeling using a pseudo-first-order model accurately reproduced the extraction profiles, yielding increasing rate constants and equilibrium conversions with temperature. The low activation energy (~12 kJ·mol⁻¹) indicates that lithium dissolution proceeds through weakly activated reaction–solution interactions rather than diffusion through a product layer. These findings provide a mechanistic basis for understanding lithium release from clay-hosted ores and highlight the importance of optimizing acid concentration, temperature, and oxygen availability to improve hydrometallurgical processing of clay-type lithium deposits. Full article

Studies of complex natural environments often focus on either biodiversity or on isolating organisms with specific properties. In this study, we sought to widen this perspective and achieve both. In particular, hypersaline ecosystems, such as the Sečovlje salt pans (Slovenia), are particularly promising sources of novel bioactive compounds, as their microorganisms have evolved adaptations to desiccation and high light intensity stress. We applied shotgun metagenomics to assess microbial biodiversity under low- and high-salinity conditions, complemented by isolation and cultivation of photosynthetic microorganisms. Metagenomic analyses revealed major shifts in community composition with increasing salinity: halophilic Archaea became dominant, while bacterial abundance decreased. Eukaryotic assemblages also changed, with greater representation of salt-tolerant genera such as Dunaliella sp. Numerous additional microorganisms with biotechnological potential were identified. Samples from both petola and brine led to the isolation and cultivation of Dunaliella sp., Tetradesmus obliquus, Tetraselmis sp. and cyanobacteria Phormidium sp./Sodalinema stali, Leptolyngbya sp., and Capilliphycus guerandensis. The newly established cultures are the first collection from this hypersaline environment and provide a foundation for future biodiscovery, production optimization, and sustainable bioprocess development. The methods developed in this study constitute a Toolbox Solution that can be easily replicated in other habitats. Full article

Mineral extraction from brine solutions is a vital issue for resource recovery in many fields of industry, especially in desalination processes. Usually, the solubility limit is viewed as a key factor that plays a determinant role in the efficiency of a prescribed process. This paper suggests the investigation of the influence of ionic strength, which is a measure of the total concentration of all dissolved ions, on the solubility limits in brines that are extracted from desalination facilities in Kuwait before discharging them into the Persian Gulf. For this purpose, the solubility of two main minerals (CaSO₄ and Mg(OH)₂) was measured for several values of ionic strength achieved by adjusting the concentration of the brine solutions. Brine samples were characterized and concentrated to achieve ionic strength values that are in the range of 1.1–2.0 mol/L. An adapted supersaturation-equilibration method was applied to determine solubility limits. Results show a non-linear relationship between ionic strength and the solubility limit of the target minerals, with behavior similar to that which could be found in the literature. In the case of CaSO₄, it was found that the solubility exhibits an increase (salting in effect) at low ionic strength, followed by a decrease at higher ionic strength (>1.1 M) (salting-out effect). On the other hand, the solubility of Mg(OH)₂ in Kuwait brine water was shown to decrease as the ionic strength increased. These trends, validated against literature data, are attributed to non-ideal solution behavior and specific ion interactions in the complex brine matrix. The findings of this work provide crucial insights for process design, enabling more precise control over precipitation steps and enhancing the overall yield and economic viability of mineral extraction from complex brine resources. Full article

Silicalite nanosheet (SN) laminated membranes are promising for pervaporation (PV) desalination of concentrated brines for water purification and critical material concentration and recovery. However, scaling up the SN-based membranes is limited by inefficient synthesis of monodispersed open-pore SN single crystals (SNS). Here, we report a scalable approach to fabricate multilayered silicalite nanosheet plate (SNP) laminated membranes on porous alumina and PVDF substrates and demonstrate their excellent PV desalination performance for simulated brines containing lithium and high total dissolved salts (TDS). At 73 ± 3 °C, the SNP laminated membrane on alumina support achieved a remarkable water flux ($J_w$) of nearly 20 L/m²·h, significantly outperforming the alumina-supported SNS laminated membrane ($J_w$ = 9.56 L/m²·h), while both provided near-complete salt rejection ($r_i$ ~99.9%) when operating with vacuum pressure on the permeate side. The PVDF-supported SNS and SNP laminated membranes exhibited excellent $J_w$ (14.0 L/m²·h) and near-complete $r_i$ (>99.9%), surpassing the alumina-support SNP laminated membranes when operating by air sweep on the permeate side. However, the $r_i$ of the PVDF-supported membranes was found to decline when operating with vacuum pressure on the permeate side that was apparently caused by minimal liquid permeation through the inter-SNP spaces driven by the transmembrane pressure. With scalable SNP production, SNP-A membranes show potential for PV desalination of high-TDS solutions, especially in harsh environments unsuitable for polymer membranes. Full article