High Purity Water Research Articles

Enhancing industrial wastewater treatment: Magnetite-embedded matrix membrane for efficient tetrahydrofuran separation by pervaporation and vapor permeation techniques

The treatment of industrial wastewater is crucial for recovering water of high purity, especially considering its significance in mitigating environmental pollution and ensuring sustainable water resources. This study focuses on the purification of industrial wastewater, emphasizing the separation of tetrahydrofuran (THF) from aqueous solutions using membrane-based techniques. Composite membranes incorporating magnetic nanomaterial (magnetite) within a sodium alginate matrix were synthesized and evaluated for their effectiveness in purifying water from THF mixtures. Both Pervaporation (PV) and Vapor Permeation (VP) processes were employed, with thorough analysis conducted on the impact of magnetite content on permeate purity. The study identified optimal magnetite content for industrial wastewater treatment and developed a new membrane composition based on these findings. The VP process’s performance was evaluated by determining the permeation flux and separation factor. The highest separation factor of 460 was obtained for an 80% wt. THF-water solution in the VP process. Using these findings, the optimal magnetite content for industrial wastewater treatment was identified, and a new membrane composition was developed. The activation energies for the permeation of THF through the NaAlg-Fe20 membrane were found to be 10.50 kcal/mol and 7 kcal/mol for the VP and PV processes, respectively.

Generation-fusion strategy in metal-earth ionosome investigation using single-entity electrochemistry at the micro-water/trifluorotoluene interface

Ionosomes are water clusters/droplets formed in an organic phase via the spontaneous assembly of ionic bilayers by hydrated cations or anions. The ionosomes formed by monovalent ions, i.e., Li+, Na+, K+, Cl−, etc., have been thoroughly investigated. Herein, single nanowater clusters (viz. ionosomes) in organic solutions, which are formed by the transfer of metal earth cations (i.e., Mg2+, Ca2+, Ba2+) into organic lipophilic electrolytes, were discovered using single-entity electrochemistry (SEE). The generation-fusion strategy involving two-step potentiostatic chronoamperometry was applied to investigate single Mg2+-ionosomes at the water/α,α,α-trifluorotoluene (w/TFT) interface. After an exciting potential forced the hydrophilic ion into the organic phase, a train of current spikes with information on the integrated charges, frequency, and duration were recorded to gain insight into the ionosomes. Variates were thoroughly investigated, including the exciting potential, exciting time, recording potential, size of the applied w/TFT interface, ion species, and concentration. These results suggest that: (1) the size of a single Mg2+-ionosome was revealed; (2) the fleshly formed ionosomes are mainly located on the organic side of the w/TFT interfacial surface instead of diffusing into the organic bulk; (3) when the interface decreases, fewer ionosomes form, and the size of the ionosomes decreases; (4) the mean charge carried by a single ionosome is positively related to the charge density of a single cation; (5) by alternating the recording potential, the negative zeta potential of Mg2+-ionosomes was revealed; (6) Mg2+-ionosomes can form when the aqueous solution contains only 2 μmol·L−1 Mg2+. This work thoroughly investigated hydrated metal earth ion clusters in the organic phase via SEE and provides insights into the interface electric double layer from the electrochemistry perspective. In addition to promoting the understanding of ionosomes, this strategy can provide potential applications to identify high-purity water.

Green Hydrogen Production From Non-Traditional Water Sources: A Sustainable Energy Solution With Hydrogen Storage and Distribution.

Green hydrogen development plays an essential role in creating a sustainable and environmentally conscious society while reducing reliance on traditional fossil fuels. Proton Exchange Membrane Water Electrolysers (PEMWEs), are sensitive to water quality, with various impurities impacting their efficiency, the quality of the hydrogen produced, and the device's lifespan. High-purity water is required for PEM electrolyzers; Type II water, which is required for commercial electrolyzers, must have a resistivity greater than 1 MΩ cm, sodium, and chloride concentrations less than 5 μg/L, and total organic carbon (TOC) content less than 50 parts per billion. The majority of electrolyzers operate on freshwater, or total dissolved solids (TDS) <0.5 g/kg, whereas brackish, rainwater, wastewater, and seawater have TDSs of 1-35 g/kg, 0.01-0.15 g/kg, 0.5-2 g/kg, and 35-45 g/kg, respectively. This critical review offers, for the first time, a comprehensive overview of relevant impurities in operating electrolyzers and their impact. The findings of this study indicate that electrolysis-based H2 processes are promising options that contribute to the H2 production capacity but require improvements to produce larger competitive volumes. In addition, the main challenges and opportunities for generating, storing, transporting, and distributing hydrogen, as well as large-scale adoption are discussed.

Treatment of wastewater from oil palm industry in Malaysia using polyvinylidene fluoride-bentonite hollow fiber membranes via membrane distillation system

Membrane distillation (MD) is gaining increasing recognition within membrane-based processes for palm oil mill effluent (POME) treatment. This study aims to alter the physicochemical characteristics of polyvinylidene fluoride (PVDF) membranes through the incorporation of bentonite (B) at varying weight concentrations (ranging from 0.25 wt% to 1.0 wt%). Characterization was conducted to evaluate changes in morphology, thermal stability, surface characteristics and wetting properties of the resulting membranes. The resulting membranes were also tested using direct contact membrane distillation (DCMD) with POME as the feed solution, aiming to generate high-purity water. Results indicated that the PVDF-0.3B and PVDF-0.5B membranes achieved the highest water vapor flux. The finger-like structure and macrovoids present in these membranes aid in minimizing mass resistance during vapor transport and enhancing permeate flux. All membranes demonstrated exceptional performance in removing contaminants, eliminating total dissolved solids (TDS) and achieving over 99% rejection of chemical oxygen demand (COD), nitrate nitrogen (NN), color, and turbidity from the feed solution. The permeate water analysis showed that the PVDF-0.3B membrane had superior removal efficiency and met the standards set by the local Department of Environment (DOE). The PVDF-0.3B membrane was chosen as the preferred option because of its consistent flux and high removal efficiency. This study demonstrated that incorporating bentonite into PVDF membranes significantly enhanced their properties and performance for POME treatment.

Investigating Water and Ion Transport in a Novel Cell Design for Seawater Electrolysis

With increasing concerns about the climate change associated with the carbon dioxide emission from utilizing traditional fuels, hydrogen has become a preferred low-carbon energy carrier. For hydrogen to truly be a clean source of energy, it must be produced from a renewable source of energy through water electrolysis. Theoretically, for each kilogram of hydrogen to be produced 9 kg of high-purity water need to be consumed, thus the enormous use of clean water for H2 production may worsen the shortage of fresh water in many parts of the world.Owing to its abundance, seawater has received great attention in the field of hydrogen production; however, there are many challenges associated with the direct use of seawater for electrolysis. In traditional systems, the seawater is first deionized by reverse osmosis (RO) before being fed to the electrolyzer. The RO system adds complexity to the system and requires energy to be expended for the deionization. Therefore, modern systems have aimed to directly electrolyze seawater, but this comes with it own issues including electrode corrosion, scaling from the ions present in saline water, environmental concerns associated with competitive chlorine evolution reaction, and increased membrane resistance limiting the overall performance of saline water electrolysis. Several strategies have been proposed to overcome these challenges including developing selective electrocatalysts, blocking strategy, pH buffer strategy, etc.This project sought to overcome the issues with direct seawater utilization by designing a cell that is driven by osmotic separation, but does not require an external power source. In this device, high concentration acid/base concentrations are maintained in contact with another compartment containing seawater. The acid/base reservoirs act as draw solutions, taking water passively from seawater due to their differences in osmotic pressure. This talk will focus on the cell design and operation, and include both experimental and modeling results. The rate of water transport with various cell operating configurations was quantified alongside the rate of chloride ion crossover through the anion exchange membrane. New methods for chloride mitigation were explored – including cell operating conditions, membrane design and absorption. Multiple cell configurations will be shown and strategies for reducing the cell operating voltage will be discussed.

Effect of the oil content on green hydrogen production from produced water using carbon quantum dots as a disruptive nanolectrolyte

Considering that high-purity fresh water is employed in the green production of hydrogen via commercial water electrolyzers and that over 80% of the global population faces significant water safety risks, it is essential to explore alternative water sources. One such alternative is the use of produced water from oil extraction processes. Hence, the main objective of this study is to evaluate the effect of the oil content of oilfield production water on the production of green hydrogen by electrolysis in the presence of carbon quantum dots (CQDs). For this purpose, various electrochemical techniques, such as linear sweep voltammetry (LSV), cyclic voltammetry (CV), and potentiometry, were used to identify the effect of crude oil during hydrogen production. Thermogravimetric analysis (TGA), mass spectrometry (MS), and Fourier-transform infrared spectroscopy (FTIR) were employed to discern the adsorption of crude oil onto the electrodes, quantify the gas fractions generated during the process and identify the functional groups present after the procedure, respectively. Also, optical microscopy was employed to follow the droplet size in the emulsion. The results show that using CQDs affects the Faradaic efficiency, which increases from 77% to 83% with the incorporation of CQDs. In the presence of CQDs, the effects generated by the presence of the oil are inhibited at low oil concentrations.On the contrary, hydrogen production increases by 10.0% (0.1 mL/min) with a faradaic efficiency of 83% and a half-cell efficiency of 41%, compared to the record obtained with the maximum concentration of emulsified crude oil (400 mg/L). The mean size of the initial emulsion droplets was 3.4 μm. At the end of the test, there was evidence of complete breakage of the emulsion due to the effect of the applied electric field. No evidence of adsorption of crude oil on graphite electrodes during electrolysis is observed based on the tests. It has been shown that green hydrogen production from crude oil production water is feasible due to the proposed disruptive electrolytes in the produced water, which inhibit the effect of oil content in the O/W emulsion. This allows the implementation of a new green energy production initiative aligned with the global goal of achieving net zero emissions (NZE) by 2050. The current investigation presents a prospective alternative for harnessing the 18 kW electrical energy potential employed within emulsion-breaking processes within a Colombian field for treatment of around 1000 bpd. This alternative offers a theoretical potential for hydrogen production, approximating 7.36 kW, thus representing a promising opportunity for practical field deployment.

Research on the optical properties and effect of the transparent epoxy for the JUNO central detector

The Central Detector (CD) of the Jiangmen Underground Neutrino Observatory (JUNO) has a large acrylic sphere containing 20,000 tons of liquid scintillator (LS) and is immersed in high purity water. The CD consists of 263 acrylic spherical panels and two chimneys, which are bonded together by mass polymerization. Transmittance and stress are critical factors for the CD, with transmittance affecting JUNO's energy resolution and stress affecting the structural integrity of the detector. The bonding areas of the CD are of particular concern, leading to the development of specialized measurement systems for acrylic stress and transmittance. Stress measurements revealed the presence of higher than expected levels of stress in the bonding areas, requiring assessments and protective measures. The application of a transparent epoxy on the bonding areas was proposed as an effective structural protection measure, although it may reduce the transmittance of these areas. Consequently, the optical properties of the transparent epoxy, such as refractive index and absorbance at 420 nm, were studied using acrylic samples to analyze the effect of the epoxy application on the transmittance performance of the CD. These results are detailed and discussed in this article.

Towards the Optimization of a Photovoltaic/Membrane Distillation System for the Production of Pure Water.

The production of pure water plays a pivotal role in enabling sustainable green hydrogen production through electrolysis. The current industrial approach for generating pure water relies on energy-intensive techniques such as reverse osmosis. This study unveils a straightforward method to produce pure water, employing real-world units derived from previously simulated and developed laboratory devices. This demonstrated system is cost-effective and boasts low energy consumption, utilizing membrane distillation (MD) driven by the waste heat harnessed from photovoltaic (PV) panels. In a previous study, modeling simulations were conducted to optimize the multi-layered MD system, serving as a blueprint for the construction of prototype devices with a suitable selection of materials, enabling the construction of field-testable units. The most efficient PV-MD device, featuring evaporation and condensation zones constructed from steel sheets and polytetrafluoroethylene (PTFE) membranes, is capable of yielding high-purity water with conductivity levels below 145 μS with high flux rates.

Influence of the alcohol and water grades on surfactant-free colloidal syntheses of gold nanoparticles in alkaline water-alcohol mixtures

To make the most of the unique properties of nanomaterials, and to bridge the gap between fundamental and applied research, controlled, green, cheap and energy efficient syntheses of nanoparticles are required. In this respect, room and low temperature surfactant-free colloidal syntheses of nanoparticles obtained in low viscosity and low boiling point solvents, without additives or nature-derived extracts, are promising to develop more active (electro)catalysts. Recently, a room temperature synthesis of surfactant-free gold nanoparticles has been documented (Chem. Mater. 2023, 35, 5, 2173) that requires only water, a base such as NaOH, an alcohol and HAuCl4. Unfortunately, the syntheses of nanomaterials are often sensitive to multiple parameters and it is well acknowledged that reproducibility is a general challenge in the chemical sciences, where the synthesis of nanomaterials is no exception. Here, we investigate the effect of the water conductivity and solvent grade on the surfactant-free low temperature (ca. 30 °C) synthesis of colloidal gold nanoparticles obtained in alkaline mixtures of ethanol and water. The synthesis can be performed with relatively low-grade ethanol but requires high purity water. The importance of water with low conductivity is also stressed for syntheses where ethylene glycol and glycerol are used as source of reducing agents. The results of this study over 100 samples pave the way to greener, more controlled and scalable syntheses of surfactant-free gold nanomaterials.

Optimizing solar evaporation efficiency: integrating controllable water supply and efficient salt collection methods

Solar desalination presents a promising solution for providing high-purity fresh water in regions lacking sophisticated energy infrastructure. Specifically, the efficiency of solar-energy-driven interfacial evaporation relies on achieving a balance between supplied solar energy and the energy demand for evaporation through water supply management. Another significant challenge for practical application is salt crystallization on the photoabsorber surface. To address these issues, two strategies are proposed: I) Construction of a three-dimensional (3D) solar evaporator that achieves a balance between supplied energy and the heat energy required for interfacial evaporation (demand energy) by optimizing the height of the support structure and II) implementation of a tunable two-dimensional water supply path made of cotton. This not only facilitates optimal water supply for interfacial evaporation but also functions as a salt collection layer, enabling efficient salt collection post desalination. With the specific design of the proposed 3D solar evaporator, our device achieves a remarkable efficiency, approaching its performance limit (94%) with an evaporation rate of 2.30 kg/m/2/h, along with efficient salt collection and scalability. This work presents a novel approach for fabricating a cost-effective solar evaporator capable of consistently delivering affordable fresh water in remote areas.

Suitability of novel 3D-printed and coated vessels for water calorimetry.

In water calorimetry, absolute dose to water is determined by measuring radiation-induced temperature rises. In conventional water calorimeters, temperature detectors are housed in handmade glass vessels that are filled with high-purity water, thus mitigating radiation-induced exo/endothermic chemical reactions of impurities that would otherwise introduce additional heat gain/loss, known as heat defect. Being hand-crafted, these glass vessels may suffer from imperfections, have shape and design constraints, are often backordered, and can be prohibitively expensive. The purpose of this work is to determine suitability of 3D-printed plastic vessels that are further coated for use in water calorimetry applications, and to study their stability and characterize their associated heat defect correction factor ( . This novel vessel production technique would allow for cost-effective rapid construction of vessels that can be produced with high accuracy and designs that are simply not practical with current glass vessel construction techniques. This in turn enables water calorimetry applications in many novel radiation delivery modalities, which may include spherical vessels in GammaKnife ICON water calorimetry as an example. Eight vessels were 3D-printed using Accura ClearVue in an SLA 3D-printer. Two vessels were coated with Parylene C and four were coated with Parylene N. The water calorimetry preparation procedures followed for these vessels was identical to that of our traditional glass-vessels (i.e., same cleaning procedures, same high purity water, and same saturation procedures with high purity hydrogen gas). The performance of each vessel was characterized using our in-house built water calorimeter in an Elekta Versa using both 6MV flattening filter-free (FFF) and 18MV beams. The stability of the coating as function of time and accumulated dose was evaluated through repeated measurements. of each vessel was determined through cross-comparisons against an Exradin A1SL ionization chamber with direction calibration link to Canada's primary standard laboratory. of the two uncoated vessels differed by 2.8% under a 6MV FFF beam. Vessels coated with Parylenes resulted in a stable and reproducible heat defect for both energies. An overall of 1.001±0.010 and 1.005±0.010 were obtained for Parylene N and Parylene C coated vessels respectively. All Parylene coated vessels showed agreement, within the established uncertainties, to the zero-heat defect observed in a hydrogen-saturated glass vessel system. An additional long-term study (17 days) of a Parylene N vessel showed no change in response with accumulated dose and time. Electron microscopy images of a Parylene N coated vessel showed a uniform intact coating after repeated irradiations. An uncoated 3D-printed vessel is not viable for water calorimetry because it exhibits an unstable vessel-dependent heat defect. However, applying a Parylene coating stabilizes the heat defect, suggesting that coated 3D-printed vessels may be suitable for use in water calorimetry. This method facilitates the creation of intricate vessel shapes, which can be efficiently manufactured using 3D printing.

The role of hydrogen in promoting differences in fatigue crack growth rates observed in Type 304/304L stainless steel at elevated temperature

Hydrogen has been postulated to affect fatigue crack growth rates (FCGRs) in Type 304/304L stainless steel during exposure to high purity water (HPW) environments at elevated temperature. To assess this mechanism, FCGR testing was performed at elevated temperature (260°C) in air and pressurized hydrogen gas. Initial results indicate the measured FCGRs in hydrogen are up to 8x lower than those measured in air under comparable fatigue loading conditions. Post-test evaluation of compact tension specimens indicates crack mouth opening displacements and fracture surface morphologies generated in hydrogen that are consistent with those generated in HPW environments. Observations of crack tip blunting suggest the reduced FCGRs in elevated temperature hydrogen occur due to a decrease in the effective ΔK. Finite element plasticity modeling, using a hydrogen-dependent nonlinear kinematic hardening approach, supports the hypothesis that crack tip blunting and retarded FCGRs are due to a hydrogen-based change in cyclic behavior (e.g. cyclic creep) occurring ahead of the fatigue crack tip.

Determination of the isotonicity 1 % solution of sodium 2-((4-amino-5-thiophen-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)acetate

The aim of the work is to justify the composition of a 1 % aqueous solution of sodium 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)acetate for parenteral use. Materials and methods. The osmolality study of a 1 % solution of sodium 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)acetate was conducted using the cryoscopic method according to the State Pharmacopoeia of Ukraine (2.2.35). The calculations were based on measuring the depression of the crystallization temperature of the 1 % solution of sodium 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)acetate, 0.9 % NaCl solution, and high-purity water (Q3). The measurements of crystallization temperature were performed using a Beckman TL-1 thermometer, which allows for research with high precision up to ± 0.005 °C, making it valuable and most effective for studying isotonic concentration. Results. Temperature measurements of the crystallization of a 1 % solution under investigation, a 0.9 % NaCl solution, and high-quality purified water were conducted. Calculations of isotonic concentration were performed based on the measurement results. Conclusions. Based on the obtained experimental data on the depression of the crystallization temperature and the calculations, the amount of sodium chloride necessary for the preparation of an isotonic 1 % aqueous solution of AFI sodium 2-((4-amino-5-thiophen-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)acetate for parenteral use was established.

Nanofiltration and selective crystallisation as technologies for the recovery of chemicals from seawater desalination brine to be used as ingredients for Bio-based fertilisers

The majority of companies that operate desalination units produce significant quantities of brine, a hypersaline product whose disposal in the sea contributes to the degradation of local fauna and flora. The proposed process for the valorisation of seawater brine and recovery of high purity water consists of two precipitation steps for the recovery of Mg(OH)2 and CaCO3. After pH conditioning, the brine (without Mg2+ and Ca2+) is led to Nanofiltration unit for Na2SO4 separation from the NaCl - KCl rich stream. Monovalent salt stream is further concentrated by Multiple Effect Distillation evaporator and crystallizer and KCl is separated from NaCl by flotation using Sodium Dodecyl Sulfate as floating agent. The aforementioned micronutrients have readily been tested for their part in enhancing the agronomic performance of fertilising products, so they possess market potential to support local/national/European fertilisation purposes. Last but not least, such a nutrient recovery approach can ensure capital recovery within the expected time limitations of an investment and in some cases offset completely the treatment cost.

Novel quantitative methods to enable multispectral identification of high-purity water ice exposures on Mars using High Resolution Imaging Science Experiment (HiRISE) images

Reliable detection and characterization of water ice on the Martian surface is pivotal to not only understand its present and past climate, but to also provide valuable information on in-situ resource availability and distribution for future human exploration missions. Ice-rich features are currently identified with visible/near-IR (VNIR), thermal IR and radar data. However, their coarse spatial scale sometimes limits confident characterization of small (i.e., meter-scale) icy exposures resulting from recent activity like new impacts. Water ice bearing materials possess weaker spectral characteristics at wavelengths shorter than ∼1030 nm that may be resolved by VNIR imaging instruments like the High Resolution Imaging Science Experiment (HiRISE) and the Colour and Stereo Surface Imaging System (CaSSIS). Our study assesses the spectral capability of HiRISE colour observations to help distinguish high purity water ice exposures from ice-poor materials. We report detailed methodologies for reliable colour characterization of icy surface using unfiltered HiRISE images. We present the first quantitative approach to uniquely characterize high-purity ice-rich materials through spectral shape and spectral parameterization methods at high spatial resolution (∼50 cm/pixel). We also present three spectral parameters to aid detection of pure water ice features, while also providing statistical constraints to enable a quantitative interpretation scheme. Our methods are observed to work well in characterizing and separating ice-rich features uniquely from ice-poor and ferrous materials. However, we do observe that these methods have a lower grain size detection limit of ∼250–300 μm, and may not be able to uniquely separate frosts from ground ice exposures. We also apply these methods to better constrain the composition of bright materials exposed by recent impacts identified in previous surveys, where substantial evidence for ice-bearing materials was previously unavailable. Overall, our work proposes HiRISE colour-based methods as a novel approach for high-resolution multispectral characterization of ice-rich features on the Martian surface, which is of particular value since the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) has ceased operations.

Photoreforming of glycerol to produce hydrogen from natural water in a compound parabolic collector solar photoreactor

To improve TiO2 for H2 generation, one strategy for the separation of photogenerated charges is the formation of heterostructures with other materials. In particular, NiO is a photocatalyst known for its good stability and low cost. However, no studies at pilot scale using solar energy have been described. Consequently, an evaluation of a physical NiO:TiO2 mixture at pilot scale (25 L) with natural irradiation (2.10 m2 of sun-exposed surface) and with simultaneous glycerol photoreforming was explored. NiO:TiO2 50 mg·L−1 resulted in the highest hydrogen production, showing an STH = 1.44%, considering only the UV fraction of the solar irradiation. H2 and CO2 production were analysed by on-line GC; Glycerol, dissolved organic carbon, carboxylic acids and nickel leaching were also evaluated. The NiO:TiO2 mixtures rendered a systematically lower H2 production in natural water than in high-purity water. The increase of ionic strength increased the mean size of particle clusters, promoting rapid sedimentation. All this indicates the importance of testing under real field conditions for attaining reliable solar to hydrogen (STH) efficiency.

Practical Analysis of Tap Water Dissolved Solids Efficient Reduction

Water is an essential component in the manufacturing of oral solid dosage forms in the pharmaceutical industry. The objective of the present study is to develop a compact and easy-to-maintain one-platform solution for generating high-purity water with near to zero Total Dissolved Solids (TDS) and low conductivity for pharmaceutical applications. To achieve this objective, different purification methods were explored and integrated into a single platform. The purification process involved the use of Electro-Deionization (EDI) in combination with double-pass Reverse Osmosis (RO), an activated carbon filter, water softeners, and micron filtration. The resource water was carefully selected based on specific criteria to ensure the quality of the final purified water. The developed one-platform solution successfully produced purified water with near to zero TDS and a conductivity level below 1 micro siemens/cm2. The integrated approach involving EDI and double-pass RO, along with supplementary filtration and treatment steps, proved to be highly effective in achieving the desired purity levels. The study demonstrated that the suggested one-platform solution is a reliable and efficient method for the production of high-purity water in the pharmaceutical industry. This system offers an easily maintainable and compact solution, making it suitable for various other industries such as semiconductor manufacturing and electric power generation where purified water with zero TDS is required. By providing a robust water purification process, this solution contributes to enhancing the quality and safety of pharmaceutical products and other critical applications that rely on ultra-pure water.

A Facile Ultrapure Water Production Method for Electrolysis via Multilayered Photovoltaic/Membrane Distillation

Ultrapure water production is vital for sustainable green hydrogen production by electrolysis. The current industrial process to generate ultrapure water involves energy-intensive processes, such as reverse osmosis. This study demonstrates a facile method to produce ultrapure water from simulated seawater using a low capital cost and low-energy-consuming membrane distillation (MD) approach that is driven by the waste heat from photovoltaic (PV) panels. To optimize the PV-MD operation, modeling efforts to design a multilayered MD system were carried out. The results were used to guide the construction of several prototype devices using different materials. The best performing PV-MD device, containing evaporation and condensation regions made from steel sheets and polytetrafluoroethylene (PTFE) membranes, can produce high-purity water with conductivity less than 40 mS and flux higher than 100 g/m2 h, which is suitable for typical electrolyzer use.

Development and application of absorbed dose primary standard for 60Co and high-energy photon beams using water calorimetry

Several new glass vessels, thermistor probes, and water phantoms have been designed and built at the National Institute of Metrology (China) to upgrade and develop the existing water calorimeter. The increased plane-parallel vessels have shorter thermal stability times and shallower positioning depths (∼1.3 cm) than the previous cylindrical vessels, which makes them suitable for electron beams. The sensitivity of the new probes is 10% greater than the previous ones. In this study, detailed experimental and theoretical investigations of various factors affecting the new water calorimeter are performed. The system uncertainty of the water calorimeter is reduced and the robustness of the determination of the absorbed-dose-to-water D w is improved using a variety of geometric detector vessels and two kinds of high-purity water systems saturated with high-purity gases. This new calorimeter is employed as a primary standard for determining the D w, has achieved a combined standard uncertainty of 0.24% for a 60Co beam, 0.27% for 6 MV and 10 MV photon beams and 0.30% for a 25 MV photon beam. The beam quality conversion factors kQ of ten cylindrical and three plane-parallel ionization chambers are measured using the new calorimeter to improve the reference dosimetry accuracy of high-energy clinical photon beams.

Comprehensive Thermodynamic Evaluation of the Natural Gas-Fired Allam Cycle at Full Load

In this study, thermodynamic modeling and simulations were used to optimize the design point performance of the Allam cycle. The topic fits perfectly with the strategies for power sector decarbonization toward net zero emission. In fact, it offers an environmentally friendlier alternative to natural gas combined cycle (NGCC) plants. The focus is on oxyfuel combustion that, combined with supercritical CO2 (sCO2) stream as working fluid, produces high-purity CO2, electricity, and water by means of a highly recuperated Brayton cycle. The former is ready for sequestration, pipeline injection, or other applications, such as enhanced oil recovery or industrial processes. Being designed within the last decade, large-scale plants are poorly documented in the published literature and not yet ready for operation. Accordingly, a thermodynamic model was developed for a net power (Pn) output of 300 MW. After validation against the little data available from academic studies, simulation sets were conceived to assess the impact of main process parameters on cycle efficiency. To that end, operating conditions of the compressor, turbine, and air separation unit (ASU) were varied in a parametric analysis, preparatory to performance optimization. For the chosen layout, the maximum net electric efficiency (ηel,n) was found to be 50.4%, without thermal recovery from ASU.