Desalination Brine Research Articles

Performance simulation of solar-driven absorption heat pump-membrane distillation system for combined desalination brine concentration with feed recirculation and cooling applications

Desalination is the primary choice for securing freshwater provision in water-stressed regions and reduces the gap between rising demand and dwindling natural freshwater resources. However, global desalination plants are dominated by fossil fuel-driven desalination technologies with a 40–50 % recovery ratio. Hence, it is critical to decarbonize desalination and address brine effluent ecological concerns. In this paper, a solar-powered absorption heat pump (AHP)-membrane distillation (MD) system concept was proposed and analysed for small-scale RO plant brine reject management and space cooling applications. The MD subsystem is based on commercial MD modules with batch feed recirculation to reach saturation (from 70 to 260 g/kg salinity). The MD system's heating and cooling consumptions are supplied by the AHP (6.54 MWh and 13.47 MWh, respectively, for a complete batch cycle). The AHP is designed to supply hot water at 85 °C with 701.63 kW heating capacity and co-produced chilled water at 16 °C with a cooling capacity of 857.86 kW, about 67 % is utilized to cool down the brine reject to feed temperature. The thermal and exergy COPs were 1.273 and 0.40 at a driving heat of 135 °C. The solar-powered AHP-MD system is useful for sustainable desalination deployment besides space cooling applications.

The evolutive role of shoot apical meristems in the adaptation of angiosperms to life at sea and the jump to potential environmental biotechnology applications

Seagrasses have adapted to a submerged lifestyle in seawater through a complex set of evolutionary processes. However, they show sensitivity to increases in natural salinity levels such as those commonly found in discharges of desalination plants, which have exponentially grown due to water scarcity in highly populated temperate areas, such as the Mediterranean basin. This study assessed the effects of brine-derived hypersalinity on the Mediterranean seagrass Posidonia oceanica, focusing on the metabolic responses of shoot apical meristems (SAMs). Although most physiological and genetic studies have used leaves, SAMs are more directly correlated with plant survival and might be more responsive to salinity stress. The experiments were: a controlled mesocosm of more than six practical salinity units (psu) over natural levels using either artificial salts or desalination brine and field transplantation experiments comparing two sites following the dilution plume of the brine (+5 and + 2 psu) with control. Hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS), and ascorbate were measured to determine oxidative stress and damage, as well as relative expression of genes related to osmotic regulation and oxidative responses. Overall, relative expression of genes related to osmotic regulation (SOS1, SOS3, AKT 2/3) and oxidative stress (STRK1, CAT, MnSOD, FeSOD, APX, GR) was higher in SAMs at higher brine exposures, indicating a more active metabolic response in this organ. Similarly, reactive oxygen species (ROS) production and lipid peroxidation were higher closer to brine discharge and total ascorbate lower, indicating a correlative response with stressor intensity. These findings confirm that SAMs play an essential role in P. oceanica hypersalinity responses and its adaptation to life in the marine environment. Finally, the use of P. oceanica SAMs in this study is highly recommended for an early detection of threats caused by desalination brines that may cause physiological damage and meadow regression.

Thermal seawater desalination for irrigation purposes in a water-stressed region: Emerging value tensions in full-scale implementation

Water scarcity in arid regions has driven the spread of desalination. These systems contribute to water access but come at an intensive energy cost, and lead to brine discharge and associated environmental impacts. This work aims to investigate emerging societal issues and tensions when developing and implementing a thermal desalination system to produce irrigation water in the South of Spain. This has been done in a demonstration system for solar desalination able to recover water and salts from desalination brine. For this purpose, a context-sensitive design exercise has been implemented. First, tensions between social values expressed by diverse stakeholders have been identified. Then, a set of technical scenarios for the full-scale implementation of the system were designed and evaluated, comparing them to conventional membrane desalination. The analysis indicates high economic and energy costs to avoid the environmental impacts of increasing water production.

Filtering ‘3-2’ Industrial Symbiosis Networks at a Carbon-Intensive Cluster in a Small Island Developing State to Reuse CO2 and Water

Small island developing states (SIDS) face internal and external pressures for more sustainable manufacturing e.g., economic and ecological water provision, and anti-carbon leakage tariffs. As SIDS have special developmental challenges, locally appropriate strategies are needed. In one of these SIDS, Trinidad and Tobago, is a carbon-intensive industrial cluster of global standing, the Point Lisas Industrial Estate (PLIE). So, to investigate ‘3-2’ industrial symbiosis (IS) on the PLIE, a simple enterprise input-output MILP model of a representative IS network was developed. Different quality wastewater streams and high-purity process CO2 from ammonia processes were selected as materials to be reused in: existing petrochemical plants, a mineral carbonate factory and a propylene carbonate plant. To filter the IS relations, economic and environmental objectives were set for each material. Combining economic objectives left a tri-objective problem, which was resolved with ε-constraint optimization and multi-criteria decision-making methods. Kleinberg's hub and authority scores were found to give beneficial insight into the solved IS networks. Potential revenue-generating opportunities were uncovered for sharing and reusing water and process CO2. The results suggest adding two proposed carbonate factories could increase the mass of CO2 reused in the cluster by 10.4% and mitigate releasing 5 Tg/y of rejected desalination brine.

The performance of nanofiltration membranes in seawater and desalination brine applications: Saudi Water Authority experience

The process of dual brine concentration employs an NF-RO-MBC configuration as its fundamental setup. Understanding the ion rejection capabilities of NF in seawater is crucial within this framework. Testing of fourteen commercial NF membranes using Jubail seawater revealed variations in ion rejection capabilities. Twelve membranes operated at a consistent feed pressure of 17.7 bar. The results categorized membranes based on their TDS rejection into high (≥ 45 %), medium (25–45 %), and low (< 25 %) rejection membranes. When concentrating the NF-treated SWRO brine, NF membranes can be utilized in the MBC system. Eight commercial NF membranes were evaluated with SWRO brine, where Na and Cl constituted over 96 % of the TDS. The investigation assessed the concentration performance and secured solid quantity in the reject relative to the feed by applying pressures of up to 40 bar for the conventional NF membranes and up to 65 bar for the newly introduced HPNF membranes. Among these membranes, two conventional and two HPNF membranes exhibited promise for concentrating SWRO brine. In addition, the ion rejection performance of five commercial NF membranes on SWRO brine was examined for a potential RO-NF-MBC configuration, suggesting suitable NF membranes for SWRO brine separation. Lastly, the ion rejection performance was studied in a multistage NF system with varying feed compositions at each stage and compared with projected performance. The accumulated NF membrane performance database will be utilized to optimize the overall membrane system configuration for seawater and brine separation and concentration.

Underpinning the Role of Nanofiltration and Other Desalination Technologies for Water Remediation and Brine Valorization: Mechanism and Challenges for Waste‐to‐Wealth Approach

Desalination brine can negatively impact the marine environment in several ways, although there are ongoing discussions regarding the severity and magnitude of environmental effects. A fascinating strategy to lessen any adverse effects is to undertake resource recovery from the brine, which also has the potential for additional revenue generation. More recently, the increasing demand for secure and less geographically restricted sources of precious or rare earth minerals, integrated with growing awareness of waste management and environmental sustainability, is driving the development of economically viable technologies to recover valuable materials from waste streams. This article provides an overview of different methods and technologies, including reverse osmosis (RO), electrodialysis (ED), and distillation, that can be used to recover precious materials, including Li, Mg, Na, and Rb and valuable blends from various waste sources and thus create a more sustainable and circular economy. The mechanisms are discussed in detail, including electrochemical processes (electrolysis, ED, and capacitive deionization), thermal desalination (multistage flash distillation and membrane distillation), pressure‐driven desalination (RO and nanofiltration), and microbial desalination cells. Challenges associated with recovering precious materials from waste streams, such as fouling, scaling, and environmental impact, along with further research directions and potential applications of desalination technologies, are also addressed.

Production of boric acid by bipolar membrane electrodialysis: Evaluation of commercial and polyelectrolyte multilayers-coated ion exchange membranes

Boron is an essential element for many industrial sectors, but the European Union (EU) is entirely dependent on imports for its boron supply. To ensure a sustainable supply of boron for the EU, developing recovery strategies from secondary sources is essential. Thus, boron recovery from seawater reverse osmosis (SWRO) desalination brines using bipolar membrane electrodialysis (BMED) as part of a multi-mineral brine mining process is proposed. BMED experiments were conducted with 35 triplets of commercial membranes (100 cm2), using sodium borate solution (92.5 mM) as feed, at three different pHs (2, 9 and 12), identifying pH 12 as the best option. Moreover, commercial ion exchange membranes from PCA GmbH and Mega a.s. were coated with polyelectrolyte multilayers using layer-by-layer technique. Characterization of the coated membranes included zeta potential, contact angle, ATR-FTIR, transport number and ion exchange capacity analyses. Subsequent BMED experiments with three triplets comparing virgin and modified membranes (100 cm2), using sodium borate solution (92.5 mM) as feed, demonstrated that the coating with 4 bilayers increased the selectivity of membranes. Although the coated RALEX membranes presented the highest selectivity (7.2 for B(OH)4-/Na+ in the acid compartment), uncoated PCA membranes were the optimal choice for H3BO3 and NaOH production due to higher Na and B removal (97 %), higher concentration factors (2.5 for the acid and 4.3 for the base), and higher current efficiency for H3BO3 production (78 %).

Production of Low-Cost Adsorbents within a Circular Economy Approach: Use of Spruce Sawdust Pretreated with Desalination Brine to Adsorb Methylene Blue.

A sustainable low-cost activated carbon substitute was produced based on pretreated lignocellulosic biomass, especially spruce sawdust. A harmful liquid waste, desalination brine, was used for the treatment of a solid wood industry waste, spruce sawdust. This approach is in the circular economy theory and aims at the decarbonization of the economy. Pretreated sawdust was tested as an adsorbent appropriate for the removal of a commonly used pollutant, methylene blue, from industrial wastewater. The adsorption capacity of the pretreated material was found to have increased four times compared to the untreated one in the case that the Freundlich equation was fitted to the isotherms' data, i.e., the one with the best fit to the isotherm's experimental data of the three isotherm models used herein. The treatment experimental conditions with desalination brine that gave maximum adsorption capacity correspond to a 1.97 combined severity factor in logarithmic form value. Moreover, a kinetic experiment was carried out with regard to the methylene blue adsorption process. The desalination brine-pretreated sawdust adsorption capacity increased approximately two times compared to the untreated one, in the case when the second-order kinetic equation was used, which had the best fit of the kinetic data of the three kinetic models used herein. In this case, the pretreatment experimental conditions that gave maximum adsorption capacity correspond to -1.049 combined severity factor in logarithmic form. Industrial scale applications can be based on the kinetic data findings, i.e., spruce sawdust optimal pretreatment conditions at 200 °C, for 25 min, with brine solution containing 98.12 g L-1 NaCl, as they are related to a much shorter adsorption period compared to the isotherm data.

Fabrication and performance optimization of an advanced pervaporation desalination membrane: A study utilizing PVDF and hydrophilic active layer as composite

Pervaporation emerges as a promising technique for brine treatment. In this investigation, we employed a PVDF substrate layer and applied various coating solutions using a simple spray technique to produce a composite pervaporation membrane. The composite membrane's chemical structure, morphology, hydrophilicity, swelling property, surface roughness, and crosslinking conditions were thoroughly investigated. Notably, the PVDF/PEI/P(SS-MA) composite membrane exhibited outstanding desalination performance, demonstrating high salt rejection and flux of 308.7 ± 13.8 kg m−2 h−1 when subjected to a 3.5 wt% sodium chloride solution. Even at an elevated brine concentration of 20 wt%, the membrane maintained a commendable flux of 88.76 ± 5.4 kg m−2 h−1 at 72 °C. These findings underscore the efficacy of the developed composite membrane for brine desalination applications.

Potential of membrane distillation for water recovery and reuse in water stress scenarios: Perspective from a bibliometric analysis

Climate change and related issues such as water scarcity and the urgent need for a transition to sustainable energy sources have motivated the development of novel processes and techniques that can be applied for water treatment, recovery and reuse. Among these emerging processes, membrane distillation in its different configurations has been extensively studied and reported in the literature. A bibliometric analysis was performed to investigate the research documents published in the scientific database Scopus until 2024, related to use of membrane distillation for water recovery and reuse. The main quantitative attributes of the research during this period were identified. The results of this analysis showed a very low scientific production until 2005, followed by a rapid exponential increase since then. The combined contribution of the two most productive countries (China and USA respectively) accounted for more than 41 % of the total number of publications, followed by Australia and Saudi Arabia, which occupied the third and fourth positions in the ranking. Chemical engineering was the most important subject category (57.4 % contribution), closely followed by environmental sciences. The review of the most cited documents and keywords showed that membrane wetting is one of the main drawbacks that can reduce the performance of membrane distillation and the use of innovative superhydrophobic, omniphobic or Janus membranes resulted an adequate solution to avoid this problem. Moreover, the desalination of seawater, brines and other highly saline solutions can be considered as the most studied application of membrane distillation. The consideration of the energetic aspects of membrane distillation and its coupling with other technologies were identified as relevant topics during the bibliometric network analysis. Special attention was given to the potential of membrane distillation for water recovery and reuse in the Chilean context of water stress for the production of drinking water and the treatment of domestic greywater and wastewater from mining and other industrial activities.

Bound Water Enhances the Ion Selectivity of Highly Charged Polymer Membranes.

Electrochemical technologies for water treatment, resource recovery, energy generation, and energy storage rely on charged polymer membranes to selectively transport ions. With the rise of applications involving hypersaline brines, such as management of desalination brine or the recovery of ions from brines, there is an urgent need for membranes that can sustain high conductivity and selectivity under such challenging conditions. Current membranes are constrained by an inherent trade-off between conductivity and selectivity, alongside concerns regarding their high costs. Moreover, a gap in the fundamental understanding of ion transport within charged membranes at high salinities prevents the development of membranes that could meet these stringent requirements efficiently. Here, we present the synthesis of scalable, highly charged membranes that demonstrate high conductivity and selectivity while contacting 1 and 5 molal NaCl solutions. A detailed analysis of the membrane transport properties reveals that the high proportion of bound water in the membranes, enabled by the high charge content and hydrophilic structure of the polymers, enhances both the ion partitioning and diffusion selectivities of the membranes. These structure/property relationships derived from this study offer valuable guidance for designing next-generation membranes that simultaneously achieve exceptional conductivity and selectivity in high-salinity conditions.

Magnesium recovery from brackish water desalination brine and valorization in fertilizer production

The generated brine from the desalination unit hurts the environment. In this work, we try to valorize the nanofiltration and reverse osmosis brine generated from a hybrid desalination unit of treated wastewater located in Tunisia by magnesium recovery and reuse it as a cheap resource for fertilizer production. The brine was first purified by calcium removal. The pH of calcite precipitation was 11.32 and 9.78 using brine NF and brine RO respectively. After that, the filtrate was used to produce brucite. The pH of brucite precipitation was 11.3 and 9.74 for NF and RO brine respectively. 55 % of magnesium was recovered from NF brine and 65.5 % from RO respectively. To obtain a 100 % recovery rate of magnesium for brucite precipitation, the optimal molar alkaline reagent/Mg ratio was 5.5 and the pH was 11.9. The brucite was dissolved in sulfuric acid, then the Epsomite fertilizer was extracted with pure ethanol. The highest weight of epsomite was obtained for a volume ratio of acid/ ethanol of 0.8:3.5. The second fertilizer produced using brine magnesium was struvite. It was obtained for pH 9 and 11 using H2NH4PO4 acid and wastewater as a source of ammonia and phosphate respectively. 90 % and 50 % of magnesium recovery were obtained for the first and the second cases respectively. The infrared spectrum and X-ray diffractogram confirmed the brucite, epsomite, and struvite production using brine magnesium.

Multi-output machine learning for addressing the trade-off between water permeability and wetting resistance in membrane distillation

Membrane distillation (MD) has gained extensive attention for the desalination of hypersaline brine. Nevertheless, the performance of MD is often hampered by the inherent trade-off between water permeability and wetting resistance. Elucidating the fundamental basis for this trade-off is crucial for the development of membrane that minimize this limitation. To address this, we trained a multi-output machine learning (ML) model that incorporates various factors, including membrane properties, operational conditions, and solution composition, to predict the performance of MD process. Our model exhibited the best performances for prediction of permeability and wetting resistance, indicted by R2 of 0.901 and 0.873, respectively. The Shapley Additive exPlanations (SHAP) method were employed to interpret the model and extracted significant insights into the contributions of various factors to the trade-off between permeability and wetting resistance, which revealed the surprising importance of the LEP and porosity, as a route for minimizing the trade-off effect. Subsequently, multi-target optimization was performed to address the current permeability-wetting trade-off limitation and the optimal combination of LEP and porosity tailored to different application requirements were provided. This study presents a novel multi-output ML model for predicting the performance of MD process and offers mechanistic insights into the wetting resistance-water permeability trade-off, which represents a paradigm shift for the design of high-performance MD process.

A techno-economic assessment of conventional and modified Solvay processes for CO2 capture and reject brine desalination

The ongoing discharge of desalination reject brine and emission of carbon dioxide (CO2) into the environment pose a major threat to the ecosystem. In this context, the Solvay process presents a potential mitigation scheme for reducing reject brine salinity while simultaneously sequestering CO2. This work reports for the first time a systematic techno-economic assessment of the conventional (ammonia-based) and modified (calcium hydroxide-based and Potassium hydroxide-based) Solvay processes. The model evaluates the effect of reactor conversion, inlet CO2 weight%, inlet CO2 temperature, gas/liquid ratio, and brine flow rate on the CO2 and Sodium ions removal. In addition, the process cost associated with each parameter was analyzed, and the impact of implementing carbon tax on process profitability was investigated. Furthermore, the Solvay processes were evaluated using economic metrics including Net Present Value (NPV), economy of scale, and Levelized cost of water. The results suggest that the calcium hydroxide-based modified Solvay process outperforms other processes in terms of CO2 and Sodium ions removal. Moreover, for the studied parameters, the calcium hydroxide-based modified Solvay process demonstrated economic viability, yielding a decent annual profit. However, the conventional Solvay process requires a remarkable amount of expenses, yet after the implementation of 40 dollars per metric tons of CO2 as a carbon tax, the conventional Solvay reaches the break-even point. These findings underscore the importance of implementing environmentally friendly practices in the industry, as the modified Solvay process proves to be a promising solution for mitigating environmental threats and promoting sustainable operations.

Sustainable carbon-negative mineral extraction from desalination brine

Effective brine management requires an economical and sustainable methodology to treat multiple pollutants in a single reaction and recover valuable resources like fresh water and minerals. Herein, we propose a novel one-pot solution that employs electrochemical oxygen reduction reaction (ORR)-generated hydroxide (OH-) to recover valuable minerals from seawater reverse osmosis brine and capture CO2. The process efficiently extracts and recovers magnesium (Mg2+) and calcium (Ca2+) ions in the form of marketable compounds such as CaCO3, Mg(OH)2, or MgCO3, using commercially available catalysts. Our results indicate that the proposed system achieves efficient mineral recovery, reaching up to 27.7 % for Mg2+ and 63.7 % for Ca2+ at a cell current of 60 mA within 8 h. Notably, approximately 40 % of the obtained minerals exist in carbonate form, highlighting the successful mineralization and carbonization of the waste stream into valuable compounds. Moreover, it reduced energy consumption by up to 30 % compared to traditional methods. Initial technology economic analysis confirms that the proposed novel process is carbon-negative and profitable. This cutting-edge and economically competitive ORR-based system technology combines minerals recovery, carbon abatement, and wastewater stream treatment, advancing decarbonization efforts and delivering global environmental benefits, providing an alternative approach for sustainable carbon-negative mineral extraction.

Versatile GO/ANFs Aerogel for Highly Efficient Solar-Powered Water Purification in Wide Environments.

Solar-driven interfacial evaporation is a very promising choice for producing clean water. Despite the considerable investigation of pure NaCl brine purification, solar-driven complex water purification, such as real-world seawater desalination as well as domestic and industrial wastewater treatment, has rarely been investigated, mainly due to its compositions being much more complicated than NaCl brine. Herein, we developed a graphene oxide/aramid nanofiber (GO/ANFs) aerogel by a freeze-drying process. The GO/ANFs aerogel combined opened porous microchannels, superhydrophilicity, anti-oil-fouling capacity, enhanced broad-spectrum light absorption (more than 92%), and good solar/heat management. These integrated properties enabled the GO/ANFs aerogel to be an advanced solar interfacial evaporator for efficient freshwater production with the characteristics of localized heat conversion, quick water transport, and salt crystallization inhibition, and the rate of steam production rate was as high as 2.25 kg m-2 h-1 upon exposure to 1 solar irradiation. Importantly, the high-water-vapor generation rate was maintained even under complicated conditions, including real-world seawater, dye water, emulsions, and corrosive liquid environments. Considering its promising adaptability to a wide range of environments, this work hopes to inspire the development of brine desalination, wastewater purification, clean water production, and solar energy utilization.

Environmental health risk of brine disposal for reverse osmosis water desalination plants: A case study in Bandar Abbas city, Iran

Reverse osmosis desalination brine (RODB) is a concentrated by-product containing higher salinity and turbidity and chemicals added to the raw water. As the RODB discharge has caused many environmental concerns, this case-control study investigated the (RODB) impact on the coastal environment. Five RODB Receiving beaches and one control point were selected, 84 samples of RODB, seawater, and coastal sediments were taken then chemical, physical, and biological parameters were measured. As well as environmental risk was assessed. The seawater salinity and turbidity on the RODB-receiving beaches were higher than the control point, and the population and diversity of plankton were lower. The content of some heavy metals was higher in the sediments affected by RODB. Low to moderate degrees of heavy metal-related environmental threat was calculated. The discharge of RODB leads to changes in the coastal ecosystem quality and can be an environmental hazard, therefore, it requires serious monitoring and control programs.

Oilfield Brine as a Source of Water and Valuable Raw Materials—Proof of Concept on a Laboratory Scale

Oilfield brine is the largest byproduct stream generated during the extraction of crude oil and natural gas and may be considered a resource for the production of potable water and valuable raw materials. The high salinity of such waters limits the application of typical membrane-based techniques. In most oilfields, waste cold energy from the process of the low-temperature separation of natural gas is available and may be used as a source of cold for the freezing desalination (FD) of brine. As a result of the FD process, two streams are obtained: partially desalinated water and concentrated brine. The partially desalinated water may be suitable for non-potable applications or as a feed for membrane desalination. The concentrated brine from the FD could be used as a feed for the recovery of selected chemicals. This paper focuses on verifying the above-described concept of the freezing desalination of oilfield brine on a laboratory scale. The brine from a Polish oilfield located in the Carpathian Foredeep was used as a feed. Four freezing–thawing stages were applied to obtain low-salinity water, which subsequently was treated by reverse osmosis. The obtained permeate meets the criteria recommended for irrigation and livestock watering. The concentrated brine enriched with iodine (48 mg/L) and lithium (14 mg/L) was subjected to recovery tests. Ion exchange resin Diaion NSA100 allowed us to recover 58% of iodine. Lithium recovery using Mn- and Ti-based sorbents varies from 52 to 93%.

Studies on the Desalination of Gold-Metallurgy Brine with Pretreatment and Electrodialysis Reversal at Pilot-Scale Level

Studies on the Desalination of Gold-Metallurgy Brine with Pretreatment and Electrodialysis Reversal at Pilot-Scale Level

Maximizing water recovery from reverse osmosis for agricultural brine reuse in Kenya

Water-stressed regions like Kenya rely on saline water sources, which can pose serious health hazards if not treated. While desalination is a burgeoning solution, safe disposal of desalination brine is often infeasible or too expensive. To circumvent this disposal challenge, we examine the maximum desalination recovery ratio (RRmax) for which desalination brine can safely be reused for many agricultural applications. Water samples from the Mara Triangle and data from past studies were collected and analyzed to measure contaminant concentrations against established safety limits of salinity and potentially hazardous elements for multiple agricultural use cases. The results suggest that high water recoveries were possible in the Mara Triangle, with the maximum recovery ratio reaching greater than 94% and 98% for crop irrigation and livestock watering, respectively. Brine reuse in this region was mostly limited by salinity, with Boron content ranking second. The most salt-tolerant crops (i.e., barley, sorghum, and wheat) were shown to be cultivable in all locations. According to calculations of the Heavy Metal Evaluation Index, groundwater in the Mara Triangle was generally safer for direct use by all users than the surface waters sampled in the past Lake Victoria and Nairobi studies.