Disinfection of corona and myriad viruses in water by non-thermal plasma: a review

Pressurized microwave-assisted hydrothermal treatment with various salts for efficient production of monosaccharides from rice straw

This study proposed a two-stage pressurized microwave hydrothermal treatment with a catalyst, followed by enzymatic saccharification, as a pretreatment method for efficiently converting cellulose and hemicellulose from rice straw into glucose and xylose. The use of various inorganic salts and dilute sulfuric acid as catalysts enhances sugar production. Using 1 wt% sulfuric acid as a catalyst at 150 °C for 5 min for the first-stage and then 180 °C for 5 min for the second-stage yielded the highest sugar production from rice straw compared with other inorganic salts tested. The filtrate and enzymatic saccharification solution contained a total sugar of 0.434 g/g-untreated rice straw (i.e. 0.302 g-glucose/g-untreated rice straw and 0.132 g-xylose/g-untreated rice straw). When inorganic salts such as NaCl, MgCl2, CaCl2, and FeCl3 were used as catalysts, the highest sugar yield of 0.414 g/g-untreated rice straw (i.e. 0.310 g-glucose/g-untreated rice straw and 0.104 g-xylose/g-untreated rice straw) was obtained when using 1 wt% FeCl3 at 170 °C for 5 min in the first-stage and 190 °C for 5 min in the second-stage, with a value close to that of 1 wt% sulfuric acid. These findings suggest that two-stage treatment with a catalyst is a suitable pretreatment method for the production of glucose and xylose from rice straw owing to the different hydrolysis temperatures of cellulose and hemicellulose.

Hydrogel composites based on chitosan and CuAuTiO2 photocatalysts for hydrogen production under simulated sunlight irradiation

This study explored the photocatalytic hydrogen evolution reaction (HER) using novel biohydrogel composites comprising chitosan, and a photocatalyst consisting in TiO2 P25 decorated with Au and/or Cu mono- and bimetallic nanoparticles (NPs) to boost its optical and catalytic properties. Low loads of Cu and Au (1 mol%) were incorporated onto TiO2 via a green photodeposition methodology. Characterization techniques confirmed the incorporation of decoration metals as well as improvements in the light absorption properties in the visible light interval (λ > 390 nm) and electron transfer capability of the semiconductors. Thereafter, Au and/or Cu NP-supported TiO2 were incorporated into chitosan-based physically crosslinked hydrogels revealing significant interactions between chitosan functional groups (hydroxyls, amines and amides) with the NPs to ensure its encapsulation. These materials were evaluated as photocatalysts for the HER using water and methanol mixtures under simulated sunlight and visible light irradiation. Sample CuAuTiO2/ChTPP exhibited a maximum hydrogen generation of 1790 μmol g-1 h-1 under simulated sunlight irradiation, almost 12-folds higher compared with TiO2/ChTPP. Also, the nanocomposites revealed a similar tendency under visible light with a maximum hydrogen production of 590 μmol g-1 h-1. These results agree with the efficiency of photoinduced charge separation revealed by transient photocurrent and EIS.

Isotherm-kinetic equilibrium investigations on absorption remediation potential for COD and ammoniacal nitrogen from leachate by the utilization of paper waste sludge as an eco-friendly composite filler

The paper industry is a major environmental polluter due to paper waste sludge (PWS), often disposed of in hazardous ways. The techniques are employed to disposing of PWS are posing significant environmental hazards and risks to well-being. This study aims to evaluate PWS as a potential replacement for commercial adsorbents like AC and ZEO in treating stabilized leachate. Contact angle analysis of PWS was 92.60°, reveals that PWS to be hydrophobic. Batch adsorption experiments were conducted with parameters set at 200 rpm stirring speed, 120 min contact time, and pH 7. Optimal conditions for COD and NH3-N removal were identified at 120 min contact time, 200 rpm stirring speed, pH 7, and 2.0 g PWS ratio. Removal percentages for COD and NH3-N were 62% and 52%, respectively. Based on the results of the isotherm and kinetic studies, it was observed that the Langmuir and Pseudo second order (PSO) model exhibited greater suitability compared to the Freundlich and Pseudo first order (PFO) model, as indicated by higher values of R-squared (R2). The R-squared of Langmuir for COD and NH3-N were 0.9949 and 0.9919 and for Freundlich model were 0.9855 and 0.9828 respectively. Whereas the R-squared of PFO for COD and NH3-N were 0.9875 and 0.8883 and for PSO were 0.9987 and 0.9909 respectively.

Research on carbon dioxide capture materials used for carbon dioxide capture, utilization, and storage technology: a review

In recent years, climate change has increasingly become one of the major challenges facing mankind today, seriously threatening the survival and sustainable development of mankind. Dramatically increasing carbon dioxide concentrations are thought to cause a severe greenhouse effect, leading to severe and sustained global warming, associated climate instability and unwelcome natural disasters, melting glaciers and extreme weather patterns. The treatment of flue gas from thermal power plants uses carbon capture, utilization, and storage (CCUS) technology, one of the most promising current methods to accomplish significant CO2 emission reduction. In order to implement the technological and financial system of CO2 capture, which is the key technology of CCUS technology and accounts for 70-80% of the overall cost of CCUS technology, it is crucial to create more effective adsorbents. Nowadays, with the development and application of various carbon dioxide capture materials, it is necessary to review and summarize carbon dioxide capture materials in time. In this paper, the main technologies of CO2 capture are reviewed, with emphasis on the latest research status of CO2 capture materials, such as amines, zeolites, alkali metals, as well as emerging MOFs and carbon nanomaterials. More and more research on CO2 capture materials has used a variety of improved methods, which have achieved high CO2 capture performance. For example, doping of layered double hydroxides (LDH) with metal atoms significantly increases the active site on the surface of the material, which has a significant impact on improving the CO2 capture capacity and performance stability of LDH. Although many carbon capture materials have been developed, high cost and low technology scale remain major obstacles to CO2 capture. Future research should focus on designing low-cost, high-availability carbon capture materials.

Efficient isomerization of glucose into fructose by MgO-doped lignin-derived ordered mesoporous carbon

The conversion of glucose into fructose can transform cellulose into high-value chemicals. This study introduces an innovative synthesis method for creating an MgO-based ordered mesoporous carbon (MgO@OMC) catalyst, aimed at the efficient isomerization of glucose into fructose. Throughout the synthesis process, lignin serves as the exclusive carbon precursor, while Mg2+ functions as both a crosslinking agent and a metallic active center. This enables a one-step synthesis of MgO@OMC via a solvent-induced evaporation self-assembly (EISA) method. The synthesized MgO@OMCs exhibit an impeccable 2D hexagonal ordered mesoporous structure, in addition to a substantial specific surface area (378.2 m2/g) and small MgO nanoparticles (1.52 nm). Furthermore, this catalyst was shown active, selective, and reusable in the isomerization of glucose to fructose. It yields 41 % fructose with a selectivity of up to 89.3 % at a significant glucose loading of 7 wt% in aqueous solution over MgO0.5@OMC-600. This performance closely rivals the current maximum glucose isomerization yield achieved with solid base catalysts. Additionally, the catalyst retains a fructose selectivity above 60 % even after 4 cycles, a feature attributable to its extended ordered mesoporous structure and the spatial confinement effect of the OMCs, bestowing it with high catalytic efficiency.

Excellent coagulation performance of polysilicate aluminum ferric for treating oily wastewater from Daqing gasfield: Responses to polymer properties and coagulation mechanism

The polysilicate aluminum ferric (PSAF) was synthesized via copolymerization of polysilicic acid (PSi), AlCl3 and FeCl3 for treating oily wastewater from Daqing gas field. This study investigated the effects of key preparation factors such as the degree of PSi's preactivation and the ratio of (Fe + Al)/Si and Al/Fe on both polymerization and coagulation performance exhibited by PSAF. To determine the optimal timing for introducing Al3+ and Fe3+, zeta potential, viscosity and particle size were investigated. Additionally, infrared spectroscopy, X-ray powder diffraction, polarizing microscopy and scanning electron microscope analysis were employed to investigate the structure and morphology of PSAF. The results indicate that under conditions characterized by a SiO2 mass fraction of 2.5% and pH = 4.5, an optimal timing for introducing Al3+ and Fe3+ is at 100 min when PSi exhibits moderate polymerization along with sufficient stability. When considering molar ratios such as (Al + Fe)/Si being 6:4 and Al/Fe being 5:5, respectively, PSAF falls within a "stable zone" enabling storage period up to 32 days. Moreover, Jar test results demonstrate that at a dosage of 200 mg/L PSAF for oily wastewater treatment in gas fields could reach the maximum turbidity removal efficiency up to 99.5% while oil removal efficiency reach 88.6% without pH adjustment. The copolymerization facilitates the formation of larger PSAF aggregates with positive potential, thereby augmenting the coagulants' adsorption bridging and charge neutralization capabilities. As a result, PSAF has great potential as a practical coagulant for treating oil-containing wastewater in industrial settings.

Effects of Halides on Organic Compound Degradation during Plasma Treatment of Brines

Plasma has been proposed as an alternative strategy to treat organic contaminants in brines. Chemical degradation in these systems is expected to be partially driven by halogen oxidants, which have been detected in halide-containing solutions exposed to plasma. In this study, we characterized specific mechanisms involving the formation and reactions of halogen oxidants during plasma treatment. We first demonstrated that addition of halides accelerated the degradation of a probe compound known to react quickly with halogen oxidants (i.e., para-hydroxybenzoate) but did not affect the degradation of a less reactive probe compound (i.e., benzoate). This effect was attributed to the degradation of para-hydroxybenzoate by hypohalous acids, which were produced via a mechanism involving halogen radicals as intermediates. We applied this mechanistic insight to investigate the impact of constituents in brines on reactions driven by halogen oxidants during plasma treatment. Bromide, which is expected to occur alongside chloride in brines, was required to enable halogen oxidant formation, consistent with the generation of halogen radicals from the oxidation of halides by hydroxyl radical. Other constituents typically present in brines (i.e., carbonates, organic matter) slowed the degradation of organic compounds, consistent with their ability to scavenge species involved during plasma treatment.

Solvent-thermal approach of MIL-100(Fe)/Cygnea/Fe3O4/TiO2 nanocomposite for the treatment of lead from oil refinery wastewater (ORW) under UVA light

The main purpose of this research endeavor is to reduce lead concentrations in the wastewater of an oil refinery through the utilization of a material composed of oyster shell waste (MIL-100(Fe)/Cygnea/Fe3O4/TiO2. Initially, iron oxide nanoparticles (Fe3O4) were synthesized via solvent-thermal synthesis. It was subsequently coated layer by layer with the organic-metallic framework MIL-100 (Fe) using the core-shell method. Additionally, the solvent-thermal method was utilized to integrate TiO2 nanoparticles into the magnetic organic-metallic framework's structure. Varieties of analytical analysis were utilized to investigate the physical and chemical properties of the synthetic final photocatalyst. Nitrogen adsorption and desorption technique (BET), scanning electron microscopy (SEM), scanning electron diffraction pattern (XRD), and transmission electron microscopy (TEM). Following the characterization of the final photocatalyst, the physical and chemical properties of the nanoparticles synthesized in each step, several primary factors that significantly affect the removal efficiency in the advanced oxidation system (AOPs) were examined. These variables consist of pH, photocatalyst dosage, lead concentration, and reaction temperature. The synthetic photocatalyst showed optimal performance in the removal of lead from petroleum wastewater under the following conditions: 35 °C temperature, pH of 3, 0.04 g/l photocatalyst dosage, and 100 mg/l wastewater concentration. Additionally, the photocatalyst maintained a significant level of reusability after undergoing five cycles. The findings of the study revealed that the photocatalyst dosage and pH were the most influential factors in the effectiveness of lead removal. According to optimal conditions, lead removal reached a maximum of 96%. The results of this investigation showed that the synthetic photocatalyst, when exposed to UVA light, exhibited an extraordinary capacity for lead removal.

Tetracycline removal from wastewater via g-C3N4 loaded RSM-CCD-optimised hybrid photocatalytic membrane reactor

In this study, a split-type photocatalytic membrane reactor (PMR), incorporating suspended graphitic carbon nitride (g-C3N4) as photocatalyst and a layered polymeric composite (using polyamide, polyethersulfone and polysulfone polymers) as a membrane was fabricated to remove tetracycline (TC) from aqueous solutions as the world's second most used and discharged antibiotic in wastewater. The photocatalyst was synthesised from melamine by ultrasonic-assisted thermal polymerisation method and, along with the membrane, was characterised using various methods, including Brunauer-Emmett-Teller analysis (BET), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), Field emission scanning electron microscopy (FESEM), and Ultraviolet-visible spectroscopy (UV-Vis). The PMR process was optimised, using Design-Expert software for tetracycline removal in terms of UV irradiation time, pH, photocatalyst loading, tetracycline concentration, and membrane separation iteration. It was revealed that a membrane-integrated reactor as a sustainable system could effectively produce clean water by simultaneous removal of tetracycline and photocatalyst from aqueous solution. The maximum removal of 94.8% was obtained at the tetracycline concentration of 22.16 ppm, pH of 9.78 with 0.56 g/L of photocatalyst in the irradiation time of 113.77 min after six times of passing membrane. The PMR system showed reasonable reusability by about a 25.8% drop in TC removal efficiency after seven cycles at optimal conditions. The outcomes demonstrate the promising performance of the proposed PMR system in tetracycline removal from water and suggest that it can be scaled as an effective approach for a sustainable supply of antibiotic-free clean water.

Advancement in nanomaterials for environmental pollutants remediation: a systematic review on bibliometrics analysis, material types, synthesis pathways, and related mechanisms

Environmental pollution is a major issue that requires effective solutions. Nanomaterials (NMs) have emerged as promising candidates for pollution remediation due to their unique properties. This review paper provides a systematic analysis of the potential of NMs for environmental pollution remediation compared to conventional techniques. It elaborates on several aspects, including conventional and advanced techniques for removing pollutants, classification of NMs (organic, inorganic, and composite base). The efficiency of NMs in remediation of pollutants depends on their dispersion and retention, with each type of NM having different advantages and disadvantages. Various synthesis pathways for NMs, including traditional synthesis (chemical and physical) and biological synthesis pathways, mechanisms of reaction for pollutants removal using NMs, such as adsorption, filtration, disinfection, photocatalysis, and oxidation, also are evaluated. Additionally, this review presents suggestions for future investigation strategies to improve the efficacy of NMs in environmental remediation. The research so far provides strong evidence that NMs could effectively remove contaminants and may be valuable assets for various industrial purposes. However, further research and development are necessary to fully realize this potential, such as exploring new synthesis pathways and improving the dispersion and retention of NMs in the environment. Furthermore, there is a need to compare the efficacy of different types of NMs for remediating specific pollutants. Overall, this review highlights the immense potential of NMs for mitigating environmental pollutants and calls for more research in this direction.

ASPAD dynamic simulation and artificial neural network for atenolol adsorption in GGSWAC packed bed column

This study aimed to assess the dynamic simulation models provided by Aspen adsorption (ASPAD) and artificial neural network (ANN) in understanding the adsorption behavior of atenolol (ATN) on gasified Glyricidia sepium woodchips activated carbon (GGSWAC) within fixed bed columns for wastewater treatment. The findings demonstrated that increasing the bed height from 1 to 3 cm extended breakthrough and exhaustion times while enhancing adsorption capacity. Conversely, higher initial ATN concentrations resulted in shorter breakthrough and exhaustion times but increased adsorption capacity. Elevated influent flow rates reduced breakthrough and exhaustion times while maintaining constant adsorption capacity. The ASPAD software demonstrated competence in accurately modeling the crucial exhaustion points. However, there is room for enhancement in forecasting breakthrough times, as it exhibited deviations ranging from 6.52 to 239.53% when compared to the actual experimental data. ANN models in both MATLAB and Python demonstrated precise predictive abilities, with the Python model (R2 = 0.985) outperforming the MATLAB model (R2 = 0.9691). The Python ANN also exhibited superior fitting performance with lower MSE and MAE. The most influential factor was the initial ATN concentration (28.96%), followed by bed height (26.39%), influent flow rate (22.43%), and total effluent time (22.22%). The findings of this study offer an extensive comprehension of breakthrough patterns and enable accurate forecasts of column performance.

Influencing factors and mechanism of CO2 adsorption capacity of FA-based carbon sequestration materials

Carbon dioxide mineral carbonisation is a means to achieve permanent carbon dioxide storage, this paper to solid waste materials as the main raw material to prepare fly ash-based carbon dioxide storage materials. Through the design of carbon dioxide adsorption experimental setup to study the main factors affecting the adsorption capacity of the fly ash-based storage materials, the experimental results show that, the fly ash mass fraction decreased from 90 to 10%, the water-cement ratio increased from 0.4 to 0.8 when the CO2 adsorption of fly ash-based materials increased by 82% and 30%, respectively. The effect of strong alkali on CO2 adsorption capacity was also investigated in this paper, and the results showed that the CO2 adsorption of the fly ash-based material sample with 10 ml NaOH added increased by 197% compared with that of the sample with 5 ml NaOH added, whereas the adsorption amount was reduced by 85% when 25 ml NaOH was added instead, which was attributed to the accelerated hydration process of the material due to the excessive alkalinity that consumed the calcium and magnesium ions in the material, and at the same time the production of hydration products hindered the transport of CO2 within the material, which led to a decrease in CO2 adsorption.

β-Cyclodextrin functionalized magnetic polyamine-amine dendrimers for high enrichment and effective analysis of trace bisphenolic pollutants in beverages

Bisphenols (BPs) are typical endocrine disruptors, which can cause great effects on environmental, organisms and human health. In this study, β-Cyclodextrin (β-CD) functionalized polyamidoamine dendrimers-modified Fe₃O₄ nanomaterials (MNPs@PAMAM (G3.0)@β-CD) were facilely synthesized. It exhibited good adsorption capacities for BPs, which was utilized to construct a sensitive tool in combination with high performance liquid chromatography for monitoring BPs such as bisphenol A (BPA), tetrabromobisphenol A (TBBPA), bisphenol S (BPS), bisphenol AF (BPAF) and bisphenol AP (BPAP) in beverage samples. The factors affecting the enrichment were examined such as generation of adsorbent, dosage of adsorbent, type and volume of eluting solvent, elution time and pH value of sample solution. The optimal parameters for enrichment was as follows: dosage of adsorbent, 60 mg; adsorption time, 50min; sample pH, pH7; elutent, 9 mL mixture of methanol and acetone(1:1); elution time, 6min; sample volume, 60 mL. The experimental results demonstrated that the adsorption conformed to pseudo-second-order kinetic model and Langmuir adsorption isotherm model. The results showed the maximum adsorption capacities of BPS, TBBPA, BPA, BPAF and BPAP were 131.80 μgg^-1, 139.84 μgg^-1, 157.08 μgg^-1, 142.11 μgg^-1 and 134.23 μgg^-1, respectively. Under optimal conditions, BPS had good linear relationship over range from of 0.5-300 μgL^-1, and the linear ranges of BPA, TBBPA, BPAF and BPAP ranged from 0.1 to 300 μgL^-1. The limits of detection (S/N = 3) for BPs were good in range of 0.016-0.039 μgL^-1. The spiked recoveries of target bisphenols (BPs) in beverages were approving over range from 92.3% to 99.2%. The established method possessed merits of easy to operate, good sensitivity, rapidness as well as environmental friendliness, and which earned great application potential for the enrichment and detection of trace BPs in practical samples.

Natural-based coagulants/flocculants as sustainable market-valued products for industrial wastewater treatment: a review of recent developments

Industrial wastewater is categorized as a voracious consumer of fresh water and a high-strength source of pollution. Coagulation-flocculation is a simple and cost-effective technique for removing organic/inorganic compounds and colloidal particles from industrial effluents. Despite the outstanding natural properties, biodegradability, and efficacy of natural coagulants/flocculants (NC/Fs) in industrial wastewater treatment, their significant potential to remediate such effluents is underappreciated, particularly in commercial scale applications. Most reviews on NC/Fs focused on the possible application of plant-based sources such as plant seeds, tannin, certain vegetables/fruit peels, and their lab-scale potential. Our review expands the scope by examining the feasibility of using natural materials from other sources for industrial effluent decontamination. By analyzing the latest data on NC/Fs, we identify the most promising preparation techniques for making these materials stable enough to compete with traditional options in the marketplace. An interesting presentation of the results of various recent studies has also been highlighted and discussed. Additionally, we highlight the recent success of using magnetic-natural coagulants/flocculants (M-NC/Fs) in treating diverse industrial effluents, and discuss the potential for reprocessing spent materials as a renewable resource. The review also offers different concepts for suggested large-scale treatment systems used by MN-CFs.

Ni4 complex anchored porous silica for enhanced adsorption of organic pollutants in the wastewater

In the current study, tetranuclear Ni complex [Ni₄(LH)₄]·CH₃CN (1) (LH₃=(E)-2-(hydroxymethyl)-6-(((2-hydroxyphenyl)imino)methyl)phenol) was prepared and incorporated in sulfonic acid functionalized MCM-48 material. This composite nanoporous material was investigated for the adsorption of toxic cationic water pollutant dyes like crystal violet (CV) and methylene blue (MB) from the water solution. Thorough characterization was carried out using a variety of techniques, including NMR, ICP, powder XRD, TGA, SEM, BET, and FT-IR, to verify the phase purity, existence of guest moiety, material morphology, and other crucial variables. The adsorption property was increased with the metal complex immobilization on the porous support. The effect of various parameters on the adsorption process was discussed, including adsorbent dosage, temperature, pH, NaCl concentration, and contact time. Maximum dye adsorption was found at 0.2 mg/ml adsorbent dosage, 10 ppm dye concentration, 6-7 pH, 25 °C temperature, and 15 minutes of contact time. The adsorption of MB (methylene blue) and CV (crystal violet) dyes by Ni complex integrated MCM-48 was effective, with over 99% adsorption achieved in 15 minutes. A recyclability test was also performed, and the material is reusable up to the third cycle, with no notable decline in adsorption found. From the previous literature survey, it is clear that very high adsorption efficiency was achieved using MCM-48-SO₃-Ni in considerably short contact time which proves the novelty and effectiveness of the modified material. Ni₄ was prepared, characterized, and immobilized in sulfonic acid functionalized MCM-48, and this robust and reusable adsorbent was highly effective for the adsorption of methylene blue and crystal violet dyes with >99% adsorption efficiency in short duration.

Carbon dots fabricated by solid-phase carbonization using p-toluidine and l-cysteine for sensitive detection of copper

In this study, a label-free "turn off" fluorescent sensor has been resoundingly fabricated using carbon dots (CDs) for ultrasensitive detection of copper ions (Cu²⁺). CDs are prepared by solid phase carbonization method using p-toluidine and l-cysteine as the precursors. The synthesized CDs exhibited the highest fluorescence intensity with excitation and emission wavelengths set at 300 nm and 400 nm, respectively. The CDs were selective and sensitive to Cu²⁺ due to the static quenching mechanism. The concentration of CDs, and solution pH and incubation time were important parameters for the developed sensor. The experimental results showed that 20 mgL^-1 was enough for the analysis. As the solution pH was concerned, it was apparent that the sensor was endowed with an excellent response signal to Cu²⁺ and provided high sensitivity at pH 12. The interaction occurred very quickly, and the incubation time could be set at 1 min. The sensor provided a two-stage calibration curve to Cu²⁺ in the range of 0.05-0.7 and 0.7-4 μM with a limit of detection of 47 nM. The obtained results clearly demonstrated that this facile method was fast, reliable and selective for detecting Cu²⁺, which would explore a prospective strategy for developing effective and low-cost sensors for monitoring metal ions in aqueous environments.

Water Desalination Using Polyelectrolyte Hydrogel: Gibbs Ensemble Modeling

Polyelectrolyte hydrogels can absorb a large amount of water across an osmotic membrane as a result of their swelling pressure. On the other hand, the insoluble cross-linked hydrogel network enables dewatering under the influence of external (thermal and/or mechanical) stimuli. Moreover, from a thermodynamic perspective, a polyelectrolyte hydrogel is already an osmotic membrane. These properties designate hydrogels as excellent candidates for use in desalination, at the same time avoiding the use of expensive membranes. In this article, we present our recent theoretical study of polyelectrolyte hydrogel usage for water desalination. Employing a coarse-grained model and the Gibbs ensemble, we modeled the thermodynamic equilibrium between the coexisting gel phase and the supernate aqueous salt solution phase. We performed a sequence of step-by-step hydrogel swellings and compressions in open and closed systems, i.e., in equilibrium with a large and with a comparably small reservoir of aqueous solution. The swelling in an open system removes ions from the large reservoir, whereas the compression in a closed system decreases the salt concentration in the small reservoir. We modeled this stepwise process of continuous decrease of water salinity from seawater up to freshwater concentrations and estimated the energy cost of the process to be comparable to that of reverse osmosis.