Brackish Water Treatment Research Articles

Promising honeycombed cork activated carbon for high desalination performance brackish water treatment

Cork activated carbon (CAC), derived from natural cork, was successfully prepared through two steps of carbonation and activation, and used for desalinating brackish water. The CAC presents a uniform honeycomb structure composed of porous carbon nanoflakes (200–300nm) and large specific surface area (SSA) (2680 m2·g-1), offering transport channels and a large number of adsorption sites to NaCl solution. The CAC showed excellent capacitance (116F·g-1), small internal resistance and better charge-discharge performance. Moreover, the optimized CAC showed high desalting capacity (9.44mg·g-1), charge efficiency (46.72%), and lower energy consumption (54.19Wh·m-3) in the desalination process, superior to that of the reported biomass-based activated carbons, which can be attributed to the stable honeycomb structure, high microporous volume (0.86 cm3·g-1) and large pore size (2.43nm). This investigation demonstrates the potential application of cork granules-based CAC electrodes in the field of desalination.

2D hollow leaf shaped mesoporous carbon derived from ZIF-L for efficient capacitive deionization

Electrochemical treatment of saline or brackish water by capacitive deionization (CDI) is a novel resource-saving solution to ensure the availability of freshwater resources in the environment. MOF (metal–organic framework) derived carbon as a novel carbonaceous material in CDI has received considerable research attention. Among them, ZIF-L-derived carbon (ZC) suffers from problems such as self-aggregation, poor mesoporous structure, and low electrical conductivity, which lead to poor CDI performance. In this paper, a strategy of ZIF-L coated with polydopamine (PDA) is proposed to solve the above problems. When the amount of PDA was 0.5 g, ZIF-L@PDA0.5-derived carbon composite (ZPC0.5) is obtained for efficient capacitive deionization. The ZPC0.5 composite not only maintains the 2D leaf shaped structure consistent with ZIF-L, exposing more active sites, but also has an elevated mesopore occupancy ratio to promote solution diffusion. Meanwhile, the interaction between PDA and ZIF-L makes the ZPC0.5 have a cavity structure, which improves the mass transfer capacity. The resulting ZPC0.5 composite has a specific capacitance (165.8F g−1) that is 3.86 times higher than that of ZC (42.9F g−1). Consequently, in 1.2 V, 500 mg/L NaCl solution, the symmetric CDI cell ZPC0.5//ZPC0.5 exhibits an excellent desalination capacity (29.6 mg/g), which is 2.69 times that of the ZC//ZC.

Improvement of Salt Leaching Efficiency and Water Content of Soil through Irrigation with Electro-Magnetized Saline Water

While the advantageous effects of using magnetic and electromagnetic treatment (ET) of brackish and saline waters on soil salinity reduction in the root zone were largely reported, more studies are needed to answer questions about the soil salt leaching efficiency and the effect of the duration of the exposure to ET. For this aim, pot experiments were conducted using an Aqua-4DR physical water treatment device. The first experiment included two trials. The first trial considered five concentrations: C0:1.0; C1:4.5; C2:9; C3:13.5; and C4:18 dS m−1. The results revealed that the volume and the salt concentrations of the drained waters were significantly higher under irrigation with ET saline waters than those provided by untreated waters. The drained fraction of water varied from 20 to 26% under irrigation with untreated water and increased from 33 to 56% under irrigation with electro-magnetized water, indicating an improvement in the salt leaching. The second trial was carried out with different irrigation doses. The results showed that the higher the dose, the more obvious and significant the ET effect. The different treatment durations of water exposure revealed that the volume and salinity of drained water significantly increase as the ET duration increases. An increase in the ET duration also induces an increase in the soil water content of around 2.5%. Based on the experimental findings, we may conclude that the ET of saline water can reduce the adverse effect of salinity on the top soil, but these leached salts are carried away in depth and there is no concentration limit of water to the effect of the ET.

Photovoltaic electrodialysis makes brackish water treatment simpler

Photovoltaic electrodialysis makes brackish water treatment simpler

Long term operation of a continuous submerged photocatalytic membrane reactor utilizing membrane distillation: Membrane performance and treatment efficiency

Long term (200 h) continuous operation of a submerged photocatalytic membrane reactor utilizing direct contact membrane distillation (SPMR-DCMD) is presented. Various types of feed contaminated with ketoprofen were treated: brackish water (BW), seawater (SeaW), and secondary wastewater effluent (SE). Ketoprofen decomposition after 24 h exceeded 99.5 %, regardless of feed type. The distillate showed no toxicity to Aliivibrio fischeri. A significant decrease in flux after 100–124 h of BW and SeaW treatment occurred due to scaling, while for SE the flux remained almost constant for 200 h. This indicates that a shorter study would not allow a proper analysis of the process. A scaling layer was formed regardless of feed type, and the formation of CaSO4⋅2H2O, CaCO3 or (Ca,Mg)CO3 was proved. The porous structure of the deposit during SE treatment prevented significant flux deterioration. The formed TiO2 layer protected the membrane from damage by the growing salt crystals.

Impacts of distinct residual aluminum on gypsum scaling in nanofiltration: Identification of key species

Membrane scaling severely hinders practical application of nanofiltration (NF) for brackish water treatment. However, the contributions of residual aluminum (Al), especially various species with differing polymerization degrees and sizes, to gypsum scaling remain unclear. Herein, the complex interactions between three Al species (AlCl3, Al13 and Al30) and gypsum scaling were investigated, including surface and bulk crystallization processes. Results demonstrated that Al species adhering to the membrane surface promoted surface crystallization and altered crystal morphology. Notably, the Al13 species induced the formation of dense, complete rosette crystals causing the most severe flux decline. For bulk crystallization, Al30 was the primary species to promote nucleation. This promotion resulted from two factors: a lower nucleation energy barrier and the promoted aggregation of small crystals. Furthermore, molecular dynamics (MD) simulations revealed that the inhibition of nucleation due to the competition between Al species and calcium ions at nucleation sites was negligible compared to the strong promotion effect. These findings demonstrated that PACl exhibit higher scaling potential during NF than monomeric Al coagulants. Ultimately, the competition between surface and bulk crystallization determined the final membrane flux decline. This study offers valuable insights into the mechanisms of NF scaling caused by residual Al and guides mitigation strategies.

Vapor Pressure and Evaporation Studies of Saline Solutions on Natural and Synthetic Fabrics for Industrial Water Treatment.

In the present paper, we have conducted a comprehensive analysis of vapor pressures of both saturated and unsaturated solutions, alongside a study of evaporation using synthetic and natural fabrics for industrial applications in brackish water treatment under zero liquid discharge (ZLD) philosophy. By determining the vapor pressures of saturated solutions, we obtained results consistent with those of other researchers, extending the range of tested temperatures from 1 to 50 °C and successfully fitting the parameters of an Antoine-type equation. Similarly, positive results were achieved for unsaturated solutions, where various parameters of different equations accounting for the salt concentration were estimated, simplifying the fitting procedure. Natural evaporation tests from water surfaces using saturated solutions revealed that salts with higher associated vapor pressures exhibit higher evaporation rates. On the other hand, hydrated salts retain water in their structure and are significantly affected by ambient humidity. Evaporation studies on natural and synthetic fabrics with saturated NaCl and CuSO4·5H2O solutions showed distinct behaviors. NaCl increased both the evaporation rate and salt deposition with each cycle. In contrast, CuSO4·5H2O reduced the absorption capacity by blocking the fabric's structure, decreasing the evaporation efficiency over successive cycles.

Zero liquid discharge management: optimizing sustainable reverse osmosis desalination practices

This study introduces a Zero Liquid Discharge (ZLD) scheme for Reverse Osmosis (RO) desalination, integrating ultra-filtration pretreatment and Electrodialysis (ED) for brine concentration. The scheme divides brine reject into fractions, directing them to an electrolyser and evaporator powered by renewable energy sources. Notable findings include the treatment plant's capability to produce 792 cubic meters of fresh water daily, while decreasing salt concentration from 4,660 ppm to 30 ppm, showcasing efficient desalination. Additionally, recycling fractions of RO unit waste to various components enhances resource efficiency. The study highlights the daily production of 2,269.27 kg of hydrogen, coupled with minimal electricity consumption of 74,885.91 kWh, thereby improving overall energy efficiency. Furthermore, the utilization of solar energy significantly reduces reliance on fossil fuels, thereby promoting sustainability and mitigating the environmental impacts associated with traditional energy sources. Solar energy is a clean, renewable resource that helps decrease greenhouse gas emissions and other pollutants, contributing to cleaner air and a healthier planet. This shift towards renewable energy is crucial in addressing climate change and ensuring a sustainable future for generations to come. In the context of desalination, emphasizing environmental preservation and water security is paramount. Desalination processes, while providing essential fresh water in arid regions, often produce brine as a byproduct. The brine, with a high salt concentration of 13,648 ppm, poses a disposal challenge that can negatively impact marine ecosystems if not managed properly. This is where Zero Liquid Discharge (ZLD) systems come into play. With a ZLD index of 2.7%, these systems ensure that all wastewater is treated and reused, leaving no liquid waste behind. ZLD technology captures and recycles every drop of water, converting waste into reusable resources, thus minimizing environmental harm. The model showcased a significant decrease in brackish water extraction from 1,200 cubic meters per day to 871.52 cubic meters per day, marking a notable 27% reduction. These results highlight the promising effectiveness of the proposed ZLD scheme in enhancing the efficiency of brackish water treatment, demonstrating its potential to significantly reduce the demand for fresh water resources while achieving sustainable desalination practices. This article will present a detailed yet a simple description of reverse osmosis and ZLD, how do they correlate and how these two technologies represent the future of water treatment.

Artificial intelligence vision technology application in sustainability evaluation of solar-driven distillation device

The process of transforming brackish water into freshwater utilizing solar thermal energy is referred to as solar-driven distillation device, or solar still. Such device without fossil fuel provides significant environmental and health benefits by reducing air pollutants and remedying brackish water. The yield of purified water from conventional solar stills remains insufficient, prompting the necessity for research to enhance it by understanding the coupling effect between steam flow, heat transfer, and mass transfer. As such, computer-aided brackish water treatment comparison of the hemispherical solar still and other multi-slope solar stills is conducted in this paper, and an automatic steam&heat flow detection algorithm is developed to solve the problem of difficult data acquisition for gas-liquid transport processes. Firstly, double slope, four slope, and hemispherical solar stills are exposed to the sun in outdoor experiments, therefore the solar thermal performance of each still is analyzed through pairwise comparisons. Secondly, a large amount of experimental image data is input into neural network for training, and by continuously adjusting network parameters, the network can accurately recognize different types of images. Finally, the image to be recognized is input into the trained neural network, which outputs the category labels of the image to achieve automatic image recognition. Based on the data above, the best structure of solar-driven device is hemispherical structure, due to that the hemispherical solar still possesses the best performance in terms of distilled water yield, energy efficiency, exergy efficiency and energy payback.

Electromagnetic Water Treatment and Soil Compost Incorporation to Alleviate the Impact of Soil Salinization

This study explores the effects of alternating current-induced electromagnetic field (EMF) on mitigating brackish water irrigation and soil salinization impacts. Greenhouse experiments were conducted to evaluate the effect of EMF on plant growth, soil properties, and leaching of ions under different conditions, including using brackish water and desalinated water for irrigation and soil compost incorporation. The experiment was performed with four types of irrigation water using soil columns representing field soil layers. EMF-treated brackish water maintained a sodium adsorption ratio of 2.7 by leaching Na+ from the soil. EMF-treated irrigation columns showed an increase in soil organic carbon by 7% over no EMF-treated columns. Compost treatment reduced the leaching of NO3− from the soil by more than 15% using EMF-treated irrigation water. EMF-treated brackish water and compost treatment enhanced plant growth by increasing wet weight by 63.6%, dry weight by 71.4%, plant height by 22.8%, and root length by 115.8% over no EMF and compost columns. EMF-treated agricultural water without compost also showed growth improvements. The findings suggest that EMF treatment, especially combined with compost, offers an effective, low-cost, and eco-friendly solution to mitigate soil salinization, promoting plant growth by improving nutrient availability and soil organic carbon.

Exergy analysis for enhanced performance of integrated batch reverse osmosis – Forward osmosis system for brackish water treatment

Concept of integrated brackish water batch reverse osmosis – forward osmosis (BRO – FO) is relatively new in the field of desalination. Recovery of the reverse osmosis (RO) system can be elevated using the free piston BRO concept, and the specific energy consumption (SEC) can be reduced. This study focuses on exergy, advanced exergy, and parametric analysis of the integrated BRO - FO system. The conventional exergy analysis suggests that the largest rate of exergy destruction is associated with the system's RO membrane module and pump, with values of 6.51 and 87.06 %, respectively. However, advanced exergy analysis shows that this rate can be reduced by 3.53 % and 62.89 %, respectively. Endogenous exergy destruction of pumps and membranes is higher compared to exogenous exergy destruction. These results are utilised to determine the system's optimal performance using parametric analysis. Sensitivity analysis was utilised to obtain an optimum recovery for system design, fresh water cost (FWC), and specific solution cost (SSC). The BRO can achieve >80 % recovery with 0.43 kWh/m3 SEC, and FO technology helps to attain minimal/zero waste discharge. Thus, a FWC of 0.50 $/m3 and a SWC of 0.44 $/m3 can be achieved.

Advanced Exergy Analysis of Cascade Rankine Cycle‐Driven Reverse Osmosis System

A novel solar‐assisted cascade Rankine cycle‐driven reverse osmosis (RO) system is proposed and evaluated using conventional and advanced exergy analysis. The system comprises a solar collector as a heat input, steam Rankine cycle (SRC), and organic Rankine cycle (ORC) to generate turbine work and RO units for brackish water treatment. Water and R1233zd(E) are used as the working fluid in the SRC and ORC, respectively. The RO system is proposed to produce 1 m3 h−1 of permeate water from each RO unit. Conventional exergy analysis shows that the solar collector exhibits the highest exergy destruction of 0.798 kW, followed by the RO unit. However, advanced exergy analysis reveals that only 16.16% of the avoidable exergy in solar collectors can be reduced due to technical constraints. Advanced exergy analysis identified that endogenous avoidable exergy destruction contributes 24% of overall exergy destruction, which can be reduced by optimizing operating parameters and making technical improvements. The RO unit has a higher exogenous avoidable exergy, potentially suggesting improvements in other system component parameters. The advanced exergy analysis also prioritized the components for improving system performance in a sequence of RO high‐pressure pumps, RO modules, solar collector, ORC condenser, evaporative condenser, ORC expander, and SRC turbine.

Bruguiera gymnorhiza forms mycorrhizal associations but Rhizophora stylosa does not: A pot experiment using mangrove soil and Rhizophoraceae seedlings

Arbuscular mycorrhizal (AM) fungi often colonize the roots of mangrove plants, forming symbiotic associations with them, but colonization rates differ greatly among mangrove species. To examine differences in the colonization patterns of AM fungi, we focused on two species of mangroves (Rhizophora stylosa and Bruguiera gymnorhiza; Rhizophoraceae) and conducted a pot experiment using seedlings grown in mangrove soil watered with fresh water or brackish water (200 mM NaCl). We observed AM fungal structures such as hyphae, arbuscles, and vesicles in the roots of all B. gymnorhiza seedlings in the freshwater treatment, but rarely in the brackish water treatment. By contrast, we found no AM fungal structures in roots of any R. stylosa seedlings in either the freshwater or brackish water treatment. These results imply that B. gymnorhiza are facultatively mycorrhizal plants that have maintained the ability to form associations with AM fungi, whereas R. stylosa, which dominate habitats more seaward than those of B. gymnorhiza, may have lost the ability to form mycorrhizal associations through adaptation to extreme seaside conditions.

Characterization of Natural and Synthetic Fabrics for the Treatment of Complex Wastes.

In the present study, nine fabrics have been tested for brackish water treatment with the aim of industrial application under the concept of zero liquid discharge (ZLD). Moisture content was determined, where it was observed that the lignocellulosic fabrics had a moisture content ranging from 2.5 to 8.5%. The wetting contact angle showed that the flax with polylactic acid (LPLA) was the most hydrophobic. The determination of the liquid absorption capacity showed that, of the synthetic fabrics, the one with the highest absorption, both in distilled water and in brackish water, was the polyester (PES) fabric with an absorption of 816% compared to its initial weight. In the natural fabrics, the highest absorption capacity was shown by the wet-laid without treatment (WL-WT) fabric for both distilled water and brackish water, although it required several cycles of operation to maintain this stable absorption. Exposure to brackish water improved the absorption capacity of all samples. Mechanical and thermal characterization showed that the synthetic fabrics were more resistant than the natural fabrics, although they may compete in terms of applicability. The capillarity study showed that the most hydrophilic fabrics completed the test the fastest. Finally, the composting degradation test showed that those fabrics with polylactic acid (PLA) content degraded faster in the first 14 days and thereafter the degradation of the lignocellulosic content showed a slower degradation until 112 days. The Bam fabric did not degrade during the course of the experiment.

Erratum to: Reliability of Nanofiltration Membrane Process for Brackish Water Treatment in Baghdad City: Module Modeling and Simulation

Erratum to: Reliability of Nanofiltration Membrane Process for Brackish Water Treatment in Baghdad City: Module Modeling and Simulation

Aplikasi Beads Komposit Chitosan – Clay Sebagai Adsorben dalam Penyerapan Ion Klorida (Cl-) Pada Air Payau

Water resources found in coastal areas and islands in terms of water quality are still relatively low, so treatment is necessary. Chitosan and clay are adsorbents that can be applied in various techniques to overcome environmental pollution. Chitosan is a natural adsorbent that has a high adsorption capacity but has low mechanical stability and is easily dissolved in an acidic medium. Clay is an adsorbent with a large specific surface area and has high mechanical stability. This research uses chitosan – clay beads, which aim to increase mechanical stability environmental resistance, and efficiency in brackish water treatment. It is located in Bandar Sungai Village, Sabak Auh District, Siak Regency. The research was conducted by varying the concentration of chitosan–clay beads (1:0), (1:0,25), (1:0,5), and (1:0,75) (w/w) to decrease the chloride ion (Cl-) in brackish water. The characterization of chitosan-clay beads with the water absorption test obtained the best results at the concentration variation (1:0), which was equal to 694,079%. The mechanical strength test obtained the best results at the concentration variation (1:0,75), which was 6,23 kgf. The characterization of chitosan-clay beads using SEM showed that the beads had larger pores. The results obtained show the best chloride ion removal efficiency (Cl-) of 90,828% with a final concentration of 113 mg/L at a concentration of chitosan – clay beads of (1:0.5) with a sampling time of 30 minutes. The research results have met the quality standards set by the Government Regulation of the Republic of Indonesia Number 22 of 2021 concerning the Implementation of Environmental Protection and Management.

Extreme Monovalent Ion Selectivity Via Capacitive Ion Exchange

Capacitive deionization (CDI) is an emerging technology applied to brackish water desalination and ion selective separations. A typical CDI cell consists of two microporous carbon electrodes, where ions are stored in charged micropore via electrosorption into electric double layers. For typical feed waters containing mixtures of several cations and anions, some of which are polluting, models are needed to guide cell design for a target separation, given the complex electrosorption dynamics of each species. An emerging application for CDI is brackish water treatment for direct agricultural use, for which it is often important to selectively electrosorb monovalent Na+ cations over divalent Ca2+ and Mg2+ cations. Recently, it was demonstrated that utilizing constant-voltage CDI cell charging with sulfonated cathodes and short charging times enabled monovalent-selective separations. Here, we utilize a one-dimensional transient CDI model for a flow-through electrode CDI cell to elucidate the mechanisms enabling such separations. We report the discovery that an asymmetric CDI cell with a chemically functionalized cathode induces electric charges in the pristine anode at 0 V cell voltage, which has important implications for monovalent cation selectivity. Leveraging our mechanistic understanding, with our model we uncover a novel operational regime we term “capacitive ion exchange”, where the concentration of one ion species increases while competing species concentration decreases. This regime enables resin-less exchange of monovalent cations for divalent cations, with chemical-free electrical regeneration.

Novel insight into prior induced crystallization on brackish water nanofiltration

An ultrafiltration/nanofiltration system enhanced by induced crystallization was constructed. The aim of this study was to assess the feasibility and contribution of fouling mitigation during brackish water nanofiltration by prior induced crystallization at ultrafiltration stage. Induced crystallization and increased negative charge density caused by alkalization probably have a synergistic effect on nanofiltration (NF) scaling and fouling mitigation. The electron acceptor surface tension and water contact angle indicated that the NF membrane became more hydrophilic during the alkalization. And thus the influence of acid-base polar interactions on membrane fouling behavior was strengthened to increase the energy barrier, improved the anti-fouling capacity. The total cost of moderate alkalization was reduced to $ 0.18 per ton, indicated a great potential for practical application. Furthermore, the functional model between irreversible resistance with hydrogen ion concentration and membrane charge density was also created. This study developed a sustainable and economy approach for brackish water treatment.

Nanofiltration Membranes with Salt-Responsive Ion Valves for Enhanced Separation Performance in Brackish Water Treatment: A Battle against the Limitation of Salt Concentration.

Utilizing brackish water resources has imposed a high requirement on the design and construction of nanofiltration membranes. To overcome the limitation of high salt concentration on the nanofiltration separation performance resulting from the weakened Donnan effect, a nanofiltration membrane with the effect of salt-responsive ion valves was developed by incorporating zwitterionic nanospheres into the polyamide layer (PA-ZNs). The interaction between the nanospheres and membranes at high salinity was revealed through a combination analysis from the perspectives of water transport model, positron annihilation spectroscopy, and solute rejection, contributing to the formation of the valve effect. The PA-ZNs membrane presented a breakthrough in overcoming the limitation of increased salt concentrations on nanofiltration separation performance, achieving a high selectivity of 105 for mono/multivalent anions. To reveal the role of the ion valve effect in ion transport through the membrane, the membrane conductance was determined at different salt concentrations, confirming channel-controlled transport at low salinity and ion valve-controlled transport at high salinity. Moreover, the main membrane separation mechanisms were systematically studied. The concept of salt-responsive ion valves may contribute to expanding the application of nanofiltration in brackish water treatment.

Experimental performance analysis for reverse osmosis pilot plant subjected to different brackish salinity spectrum

The main obstacles to reverse osmosis desalination processes are high energy intensity and long-term continuity. Temperature and pressure have the greatest and most significant effects on energy use. The main objectives of the current study are to determine the pressure and temperature-dependent optimal operating parameters for a membrane desalination unit. To determine the ideal operating settings for a membrane unit, the impact of changing pressure and temperature on its performance was investigated. These two elements are closely connected to the energy consumption per cubic meter under various operating situations. The present work is experimentally carried out in a research laboratory for capacity building and future research studies in the desalination field established in the National Center of Water Research – Egypt. This laboratory is Egypt’s first multi-functional Desalination Research Station for seawater, brackish water, and related water treatment areas. The plant is equipped with online instrumentation and Data Acquisition System and 13 sensors for most physical parameters which economically affect membrane performance and desalination processes. These parameters, particularly pressure and temperature, are measured, evaluated and analyzed. According to the findings in this study, feed salinity and feed pressure both have significant impacts.At 13 bar pressure, the maximum salt rejection was 98.8%. When feed pressure is increased from 5 to 13 bars, there is a 73.3% decrease in permeate salinity. Additionally, applying a 13 bar feed pressure to water with a salinity of 1000 ppm results in the best water quality of 12 ppm. The relationship between feed pressure, brine salinity, and membrane water recovery appeared to be approximately linear and positive. More crucially, it was discovered that feed pressure, salinity, and water recovery are all constants for water permeability. A prototype for the maximum pressure (ranges from 15.6 to 10.8) and temperature (ranges from 21 to 35) at which the optimal recovery of the laboratory occurred was developed. Moreover, the developed prototype includes the corresponding permeate TDS and a specific energy for each optimal point.