Electrolyte Concentration Research Articles

Trace‐Amount of Water as An Electrolyte Additive for Sodium Metal Electrode

AbstractThe high reactivity of water toward Na metal has raised a concern about keeping the electrolytes extra‐dried. In this work, changes in water concentration in electrolytes (with and without fluoroethylene carbonate) show changes in overpotential and the surface chemistry of Na electrodes. In a symmetric cell test, the cell with pristine electrolyte (1 M NaClO4 in ethylene carbonate:propylene carbonate) sustained only 22 cycles before reaching the safety limit (5 V) at 1 mA cm−2. Meanwhile, controlling the water content (40 ppm) extended the cell's life by 3.5 times. In fluoroethylene‐carbonate‐containing electrolytes, the optimized water concentration (40 ppm) gave the minimum overpotential (12 mV) after 170 cycles. Ex situ X‐ray photoemission spectroscopy showed that water hydrolyzed fluoroethylene carbonate, which changed the Na electrode's surface chemistry. The appropriate amount of product (NaF) stabilized the electrodes’ surfaces. Electrical impedance spectroscopy showed that the controlled traces amount of water (40 ppm) always gave the minimum values for resistances. For the pristine electrolytes, the resistances attributed to the charge‐transfer process and the solid‐electrolyte interface layer increased 51 times (from 45 Ω–2290 Ω) after cycling. Meanwhile, for the optimized sample, the resistances remarkably decreased by 93 % (from 264 Ω–19 Ω) after cycling.

The cardiac sympathetic co-transmitter neuropeptide-Y is pro-arrhythmic in human cardiomyocytes by lengthening activation-recovery interval

Abstract Background Myocardial infarction (MI) is associated with sympathetic overactivity, during which the co-release of neuropeptide-Y (NPY) is prominent. NPY is associated with arrhythmia risk and mortality following ST-elevation MI, although the exact mechanisms for this in human cardiomyocytes remains unclear. Purpose We therefore tested the hypothesis that NPY signalling would alter the electrophysiology of human induced-pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) in a way that would promote arrhythmia, and that in patients being treated for MI, high NPY concentrations previously associated with ventricular arrhythmia (>27.3 pg.mL-1) would be associated with comparable ECG changes. Methods Immunohistochemistry and western blot were performed on hiPSC-CMs and ventricular biopsies from human patients undergoing valve surgery. The FRET-based sensor Epac-SH187 was expressed in hiPSC-CMs to monitor the cyclic adenosine 3’,5’-monophosphate (cAMP) response to NPY. A micro-electrode array was used to investigate the effects of NPY on a confluent layer of iPSC-CMs, measuring changes in activation, recovery, conduction velocity and spontaneous automaticity. Additionally, patients presenting with ST-elevation MI had peripheral venous [NPY] measured and compared to 12-lead ECGs recorded following stenting. Results hiPSC-CMs expressed Y1 and Y5 receptor mRNA and protein, which are also expressed in ventricular biopsies from human patients. NPY (1-100 nM) significantly reduced intracellular cAMP levels (n=65), most effectively prevented by Y5 receptor inhibition (1µM CGP71683A, n=40). In a confluent layer of hiPSC-CM, NPY (100 nM) slowed late-repolarisation represented by T-wave peak-end duration (p=0.04), which could be prevented by Y1-receptor inhibition (1 μM BIBO 3304, n=6), and caused prolongation of rate corrected activation-recovery interval (ARIc) (p=0.009, n=6) which could be abolished by Y5-receptor inhibition (n=7). NPY significantly increased automaticity to more than one site of initiation in 4/6 (66.7%) compared to 2/14 (14.3%) control plates (p=0.037), despite no change in conduction velocity. Moreover, in 65 patients being treated for ST elevation MI, those with high peripheral venous NPY concentrations were well matched in terms of cardiovascular risk factors, medications on admission, and pain to balloon times, but had significantly longer corrected QT interval (QTc) on the 12 lead ECG (p=0.04) despite no differences in PR interval, heart rate or electrolyte concentrations. Conclusions NPY slowed late repolarisation and caused ARIc prolongation, which was associated with increased automaticity in human iPSC-CMs. NPY also correlated with QTc-prolongation in patients being treated for MI and may contribute to the increased incidence of ventricular arrhythmia observed in these patients. Antagonists of Y1 and Y5 receptors may therefore offer an adjunct to β-blockade therapy to reduce the risk of ventricular arrhythmia.

Improved kitchen wastewater treatment using PbO2-coated graphite electrode

This study investigates the electrochemical treatment of kitchen wastewater (KW) using a PbO₂-coated graphite (G-PbO₂) electrode prepared via ultrasound-assisted electrochemical deposition. The G-PbO2 electrode was characterised through various techniques, including X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM), confirming the successful deposition of PbO₂ and enhanced catalytic activity. Under optimal conditions (current density 0.75 Adm−2, electrolyte concentration 1.5 gL-1, electrode distance 2 cm, and pH 3), the G-PbO₂ electrode achieved a 94 % COD reduction with an energy consumption of 0.002 kWh gCOD−1. These results highlight the superior performance of the electrode in COD removal, accompanied by low energy consumption.

Practical Lithium–Sulfur Batteries: Beyond the Conventional Electrolyte Concentration

Practical Lithium–Sulfur Batteries: Beyond the Conventional Electrolyte Concentration

Energy-conversion efficiency for producing oxy-hydrogen gas using a simple generator based on water electrolysis

Producing hydrogen efficiently through water electrolysis could greatly reduce fossil fuel consumption. As well as this renewable energy source will also help combat global warming and boost economic investment opportunities. This paper studied some factors affecting the performance of oxy-hydrogen/hydroxy (HHO) gas generator, such as applied voltage (from 10.5 to 13.0 V) and electrolyte solution concentration (from 0.05 to 0.20 M), using a dry fuel cell based on the electrolyzing technique of water. The results revealed that the HHO gas production rate, power consumption, and temperature change of electrolyte solution increased significantly with increasing the tested applied voltage and electrolyte concentration. This study concluded that the optimum conditions for producing HHO gas ranged from 11.5 to 12.0 V for applied voltage and from 0.05 to 0.10 M for KOH concentration according to the lowest specific energy and highest HHO gas generator efficiency. Under the previous optimum conditions, the highest productivity, specific energy, and efficiency of the HHO gas generator were 343.9 cm3 min−1, 3.43 kW h m−3, and 53.79%, respectively, using 12.0 V for applied voltage and 0.10 M for electrolyte solution concentration. These findings provide an unambiguous direction for adjusting the operational factors (applied voltage and electrolyte concentration) for efficient HHO gas production and use in different applications. Furthermore, the required energy to operate the HHO gas generator can be obtained from renewable sources.

Investigation into micro slotting of Cu-based shape memory alloy via µ-ECM using ethylene glycol mixed aqueous NaCl electrolyte

ABSTRACT Micro-Electrochemical Machining (µECM) presents significant promise as a future micromachining process offering higher machining rates, improved precision and the ability to work with a wide range of materials. Cu-based shape memory alloys (SMAs) have exceptional properties that make them quite difficult to machine using traditional techniques. In this investigation a new electrolyte solution consisting of ethylene glycol (EG) and NaCl has been explored while attempting µECM of Cu-SMA. The Cu-based shape memory alloy used consists primarily of Cu-53.19%, Zn-41.50%, and 5.2% other elements. Four different parameter combinations selected based on pilot experiments were used for the main experimentation conducted in four sub-sets. The influence of micromachining parameters including machining voltage, electrolyte concentration and micro-tool feed rate on µECM characteristics such as material removal rate (MRR) and surface roughness (SR) during micro-slot formation has been investigated. With the identified optimum parameters, a high-quality micro-slot was successfully machined on Cu-based shape memory alloys achieving a material removal rate of 0.323 mg/min and surface roughness of 0.384 μm. The investigation demonstrated that an ethylene glycol electrolyte containing NaCl is more suitable for µECM of micro-slots offering superior surface integrity and shape accuracy compared to a water-based electrolyte.

Association of perinatal exposition to xenobiotics with kidney volume at birth.

The state of Aguascalientes has the highest prevalence of kidney failure in young adults. A low nephron endowment has been suggested as a possible etiology. This study aims to evaluate the association between exposure to xenobiotics and low kidney volume (KV) at birth. This is a cross-sectional, observational, and descriptive study of at-term pregnant women, with no comorbidities. We collected the mother´s urine (MU), amniotic fluid (AF), and neonate´s urine (NU). Metals and non-metals were measured with inductively coupled plasma mass spectrometry, pesticides were determined with high-performance liquid chromatography, and fluoride by ion-selective potentiometry. The total KV adjusted by body surface area (TKVBS) was calculated based on the kidney ultrasound. Between March-2022 and July-2023, we included 299 women with an average of 24.2 years (± 5.1). 54.2% of neonates were male with an average weight of 3,266 gr (± 399).Factors associated with the TKVBS ≤ 5 percentile were female sex, weight gain during the pregnancy, glomerular filtration rate, methomyl concentration in AF (Odds ratio 7.41, 95% confidence interval 2.31 - 23.8, p= 0.001), 2,4-Dichlorophenoxyacetic (2,4-D) >10 ng/ml in AF (4.99, 1.58 - 15.7, p= 0.002), MU (6.1, 1.9 - 19.7, p= 0.002), and NU (5.1, 1.10 - 26.2, p= 0.023) and fluoride in MU (5.1, 1.10 - 23.5, p= 0.010), and AF (6.76, 1.28 - 35.7, p=0.024). In all matrices (MU, AF and NU) exposure to pesticides was also significantly associated with greater concentrations of electrolytes (Na, K, Ca, PO4 and Mg and oligo-elements (Zn and Fe). In neonates born to at-term women with no comorbidities, the presence of pesticides and fluoride was associated with low KV. The significant loss of electrolytes and oligoelements associated with pesticides suggests proximal tubulopathy.

Conformational isomerism breaks the electrolyte solubility limit and stabilizes 4.9 V Ni-rich layered cathodes

By simply increasing the concentration of electrolytes, both aqueous and non-aqueous batteries deliver technical superiority in various properties such as high-voltage operation, electrode stability and safety performance. However, the development of this strategy has encountered a bottleneck due to the limitation of the intrinsic solubility, and its comprehensive performance has reached its limit. Here we demonstrate that the conformational isomerism of the solvent would significantly affect the solubility of electrolytes. By transforming the configuration of solvent from cis-cis to cis-trans upon thermal triggering, we successfully break the solubility limit, and a beyond concentrated electrolyte with the lowest solvent-to-salt molar ratio of 0.70 is constructed. Transitions between cis-cis and cis-trans conformers are observed through Nuclear Magnetic Resonance (NMR) testing. The electrolyte consists entirely of anion-mediated solvation structures and promotes the formation of robust inorganic-dominated cathode electrolyte interphase. As a result, it enables stable cycling of 4.9 V-class LiNi0.8Co0.1Mn0.1O2 positive electrodes. Moreover, a high capacity of 151.2 mAh g−1 can be maintained after 1000 cycles at cut-off voltage of 4.8 V. This work provides a chemical pathway to build new concept electrolytes working under harsh conditions.

Ferrates (VI) ; Alternative products in water treatment : their electrochemical synthesis

This study focuses on determining the optimum conditions for the electrochemical generation of ferrates in concentrated NaOH solution. Various operating parameters, including electrolyte concentration, current density, temperature, electrolysis duration, and the composition and form of the anode, were investigated to enhance the yield of electrochemical ferrate (VI) ion production. The synthesized ferrates were characterized using UV-visible and FTIR spectroscopic techniques. Experimental results confirmed the formation of ferrate ions, with optimal synthesis conditions identified as follows: a current density of 11.96 mA/cm², NaOH concentration of 16 M, electrolysis time of 1 hour, temperature of 25°C, and the use of white cast iron as the anode material. These conditions were found to yield the highest efficiency for sodium ferrate production. The spectroscopic analysis effectively verified the presence of ferrate (VI) ions, providing valuable insights into the electrochemical synthesis process. This study contributes to the advancement of ferrate synthesis techniques, potentially offering an efficient route for large-scale production.

Electrochemical Synthesis of C(sp3)-Rich Heterocycles via Mesolytic Cleavage of Anodically Generated Aromatic Radical Cations.

Herein we report an electrochemical deconstructive functionalization approach for the synthesis of C(sp3)-rich heterocycles. The reaction proceeds via the mesolytic cleavage of anodically generated aromatic radical cations and the trapping of formed carbocation intermediates with internal nucleophiles. The method has been demonstrated across various arylalcohol substrates to access a diverse range of C(sp3)-rich heterocycles including tetrahydrofuran, tetrahydropyran, and pyrrolidine scaffolds (26 examples). The electrochemical method was demonstrated on a 5 mmol scale via single pass continuous flow, which utilized lower supporting electrolyte concentration and exhibited increased productivity in relation to the batch process.

Mechanism and growth kinetics of hexagonal TiO2 nanotubes with an influence of anodizing parameters on morphology and physical properties

Hexagonal TiO2 nanotubes (hTNTs) mimic a honeycomb structure, indicating their high potential as implantable materials due to their superior mechanical, chemical, and biological properties. However, the fabrication of hTNTs with a hexagonal base and six rectangular sides poses significant challenges, underscoring the importance of this research. This study developed a novel sonoelectrochemical method for synthesizing uniform hTNTs and evaluated the influence of anodizing parameters on their morphology. The effects of electrolyte concentration (ethylene glycol 90–97.5% and ammonium fluoride 0.1–0.5 wt%) and anodizing parameters (time 5–90 min, potential 10–80 V) on the morphology (diameter and length) and physical properties (porosity, specific surface area, growth factor) of hTNTs were investigated using scanning electron microscopy and anodization analysis. The methodology enabled the synthesis of hTNTs with diameters ranging from 33 ± 3 nm to 203 ± 33 nm and lengths from 1.16 ± 0.04 μm to 20.93 ± 2.37 μm. The study demonstrated that the concentrations of ethylene glycol and ammonium fluoride influenced the diameter and length of hTNTs depending on the anodizing potential. Moreover, the anodizing potential significantly affected the diameter, while both potential and time impacted the length of hTNTs. The proposed method can modify material surfaces for diverse applications.

Tuning the Solvation Structure of a Weakly Solvating Cyclic Ether Electrolyte for Wide‐Temperature Cycling of Lithium‐Sulfurized Polyacrylonitrile Batteries

AbstractSulfurized polyacrylonitrile (SPAN) cathodes in high energy‐density Li‐metal batteries have garnered widespread interest owing to their good cycling stability and moderately high capacities. However, their application is hindered by the low prevalence of advanced electrolytes that can simultaneously mitigate polysulfide generation at the cathode and stabilize the Li‐metal anode. Here, a weakly solvating electrolyte is presented, employing a single solvent tetrahydropyran (THP). The solvation structure is effectively tuned by adjusting the salt concentration to stabilize both the Li‐metal anode and SPAN cathode. This approach enables stable cycling with high SPAN loadings (≈5 mg cm−2) and lean electrolyte contents (≈5 µL mgSPAN−1) across a wide temperature range: 0 °C, room temperature, and 50 °C. A pouch cell with a high SPAN loading and a low electrolyte‐to‐SPAN (E/SPAN) ratio of 3 µL mg−1 shows a stable 79.1% capacity retention after 40 cycles. Additionally, THP can be effectively employed in localized high‐concentration electrolyte (LHCE) systems to reduce the diluent‐to‐solvent ratio for greater LHCE viability. The study demonstrates the potential of weakly solvating solvents in Li‐SPAN batteries, offering a pathway for their practical application.

Performance optimisation of new basket-shaped TiO2 photoelectrodes in a photocatalytic fuel cell utilising the response surface method: dye elimination and energy generation

ABSTRACT Response Surface Methodology (RSM) simplifies fuel cell design and offers possibilities for process improvement, operating condition optimisation, and performance improvements. By identify the best design parameters, RSM helps create fuel cell systems that are dependable, economical, and efficient. Although RSM is widely applied in many domains, more studies are still needed evaluating photocatalytic fuel cell performance in dye removal and optimising the conditions of reactions. Using RSM (central composite design), the system's ability to remove Methyl Orange (MO) and produce energy was enhanced in this study. TiO2/Ti and CuO/Cu are employed in this system as the photoelectrodes. Effective optimised parameters on contaminant removal and energy production, including dye concentration, electrolyte concentration, and pH, were achieved as 23.31 mg/L, 0.1 M, and pH = 3, respectively. 71.26% MO dye was removed, and 0.63 V, 0.19 mA/cm2, and 0.037 mW/cm2 values were recorded for the open-circuit voltage (VOC), short-circuit current (JSC), and maximum power density (PMAX), respectively, under optimal conditions, which was very close to the experimental values. The analysis of variances for dye removal and VOC, JSC, PMAX, correlation coefficient, and adjusted correlation coefficient for the four mentioned responses indicated a strong correlation between the predicted and experimental data, confirming the model's accuracy.

Precise Construction of the Triple-Phase Boundary and Its Antiphosphate Poisoning Effect in the Confined Region.

As a critical component for the oxygen reduction reaction (ORR), platinum (Pt) catalysts exhibit promising catalytic performance in High-temperature-proton exchange membrane fuel cells (HT-PEMFCs). Despite their success, HT-PEMFCs primarily utilize phosphoric acid-doped polybenzimidazole (PA-PBI) as the proton exchange membrane, and the phosphoric acid within the PBI matrix tends to leach onto the Pt-based layers, easily causing toxicity. Herein, we first propose UiO-66@Pt3Co1-T composites with precisely engineered interfacial structures. The UiO-66@Pt3Co1-T exhibits an octahedral porous framework with uniform structural dimensions and even distribution of surface nanoparticles, which demonstrate superior ORR performance compared to commercial Pt/C. The unique structure and morphology of the composites also exhibit a favorable half-wave potential in different concentrations of phosphoric acid electrolyte, regulated by the phosphoric acid adsorption site and intensity.This finding suggests that the incorporation of Co could effectively modulate the Pt d-band center, thereby enhancing the ORR performance. Furthermore, the selective adsorption of phosphoric acid by ZrO2 enables precise control over the phosphoric acid distribution. Notably, the retention of the octahedral framework post high-temperature treatment facilitates the establishment of dual transport pathways for gases and protons, leading to a stable and efficient triple-phase boundary.

In Situ STM Study of Roughening of Au(111) Single-Crystal Electrode in Sulfuric Acid Solution during Oxidation-Reduction Cycles.

Oxidation-reduction cycles (ORCs) on Au(111) in 0.1 M sulfuric acid solution change the electrode morphology due to the formation of many new nanosized islands. With increasing the cycle number, the roughness of the surface increases due to the formation of multiatomic-step adatom islands and pits. The final roughness value is a function of the applied potential window, number of ORCs, scan rate, electrolyte concentration, and any applied delay time. In a first experiment, the roughening was tracked by recording the STM images in 11 steps during 200 ORCs. The results show the formation of pyramidal islands and a linear correlation between the roughness amplitude and the cycle number. In a second experiment, the 200 cycles were studied in 38 steps, while after each step, two images were recorded with a 3 min delay by holding the potential in the double-layer window. This leads to a lower roughness increase due to the high surface mobility of the Au surface atoms, which smoothens the surface during the delay time. Finally, the oxidation-reduction charge density per cycle shows an inverse correlation with surface roughness due to the (111) terrace showing a higher surface oxidation charge than the other sites and facets. Each delay causes a strong increase in the oxidation charge which is a consequence of surface smoothening during the delays leading to an enhancement of the (111) related oxidation charge.

Electrolyte-Salts Regulated Hydrogen-Bonding Configuration and Interphase Formation Achieving Highly Stable Anode for Rechargeable Aqueous Sodium-Ion Batteries.

Hydrogen evolution reactions that cause the alkalization of aqueous electrolytes generally frustrate the structural stability and cycling performance of NaTi2(PO4)3/C anode material for rechargeable aqueous sodium-ion batteries (ASIBs). Herein, a novel highly concentrated electrolyte with a large hydrogen-evolution overpotential and hydroxide-capture ability is rationally established by incorporating a bifunctional Mg(Ac)2 additive into a concentrated NaAc aqueous solution. The highly concentrated electrolyte salts (4m NaAc+3m Mg(Ac)2) favor regulation on hydrogen-bonding configurations and kinetically shift the hydrogen evolution potential to a lower value of -1.37 V (vs Ag/AgCl). The Mg(Ac)2 additive plays particular roles in spontaneously capturing hydroxide ions generated during hydrogen evolution reactions on anode surfaces and simultaneously forming a protective Mg(OH)2-like interphase. As a result, the unique electrolyte significantly improves the structural stability and cycling performance of NaTi2(PO4)3/C anode (94.8% capacity retention after 100 cycles at 100 mA·g-1). The effect of salt concentration on hydrogen bonding configurations of aqueous electrolytes is investigated with Raman spectroscopy and FTIR spectroscopy. The interphase is identified by coupling EDS mapping, X-ray photoelectron spectroscopy, and X-ray diffraction. This work provides a new strategy for improving the cycling stability of aqueous sodium-ion batteries.

Solvent Polarity‐Induced Regulation of Cation Solvation Sheaths for High‐Voltage Zinc‐Based Batteries with a 1.94 V Discharge Platform

To address the challenge of low discharge platforms (<1.5 V) in aqueous zinc‐based batteries, highly concentrated salts have been explored due to their wide electrochemical window (~3 V). However, these electrolytes mainly prevent hydrogen evolution and dendrite growth at the anode without significantly enhancing voltage performance. Herein we introduce an approach by adjusting solvent polarity to regulate cation solvation sheaths in hybrid electrolytes, reducing Zn/Zn2+ oxidation potential and water activity. Through strong cation‐water coordination and hydrogen bonding between dimethylsulfoxide and water, the designed electrolyte, at a low concentration, achieves a broader electrochemical window (4 V) than conventional concentrated electrolytes. Using this electrolyte, a Zn/Zn battery showed an impressive cycle life of 4340 cycles, while a Zn/lithium manganate battery delivered a high discharge platform of over 1.9 V with exceptional cycling stability. A Zn‐based micro‐battery with a polyvinyl alcohol‐based hybrid electrolyte also achieved a record‐high discharge platform of 1.94 V. This work presents a promising strategy for developing low‐concentration electrolytes for high‐performance sustainable energy storage.

Solvent Polarity-Induced Regulation of Cation Solvation Sheaths for High-Voltage Zinc-Based Batteries with a 1.94 V Discharge Platform.

To address the challenge of low discharge platforms (<1.5 V) in aqueous zinc-based batteries, highly concentrated salts have been explored due to their wide electrochemical window (~3 V). However, these electrolytes mainly prevent hydrogen evolution and dendrite growth at the anode without significantly enhancing voltage performance. Herein we introduce an approach by adjusting solvent polarity to regulate cation solvation sheaths in hybrid electrolytes, reducing Zn/Zn2+ oxidation potential and water activity. Through strong cation-water coordination and hydrogen bonding between dimethylsulfoxide and water, the designed electrolyte, at a low concentration, achieves a broader electrochemical window (4 V) than conventional concentrated electrolytes. Using this electrolyte, a Zn/Zn battery showed an impressive cycle life of 4340 cycles, while a Zn/lithium manganate battery delivered a high discharge platform of over 1.9 V with exceptional cycling stability. A Zn-based micro-battery with a polyvinyl alcohol-based hybrid electrolyte also achieved a record-high discharge platform of 1.94 V. This work presents a promising strategy for developing low-concentration electrolytes for high-performance sustainable energy storage.

Unveiling the Electrostatically Driven Collapsing and Relaxation of Polyelectrolyte-Colloid Complexes: A Tunable Pathway to Colloidal Assembly.

Polyelectrolyte-colloid (PEC) complexes, ubiquitous across diverse fields, exhibit remarkable phase transitions, mimicking intricate biological assemblies. While the role of electrostatic forces in the PEC complex assembly is undeniable, achieving a holistic comprehension remains an elusive goal. This study unveils a fascinating phenomenon: the formation of highly collapsed coacervate structures in PEC complexes at elevated polyelectrolyte concentrations, followed by the swelling of complexes at even higher concentrations. Employing anionic silica colloids and cationic chitosan as a model system, small-angle X-ray/neutron (SAXS/SANS) elucidates the transition from a bead-on-a-necklace-like phase to a dense packed coacervate state (with volume fraction ∼0.62) until 3 wt % concentration of the polyelectrolyte. However, beyond 3 wt %, swelling of the dense collapsed assembly is observed. This structural evolution of PEC complexes as a function of chitosan concentration is attributed to the interplay of electrostatically driven interactions and the Donnan effect. Notably, the critical concentration for coacervation, Cs*, demonstrates a linear dependence on the initial colloid concentration. Interestingly, a complete expansion of the coacervate is observed at a high polyelectrolyte concentration, particularly for dilute colloid solutions (2 wt %). Furthermore, the addition of an electrolyte sheds light on the delicate interplay of forces. While a low electrolyte concentration partially screens charges, leading to a shift in phase diagram, higher concentrations trigger complete coacervate dissolution beyond the critical electrolyte concentration of 0.2 M, due to the complete screening of electrostatic charges.

Green Hydrogen Synthesis from Human Urine as Sustainable Bioenergy Resources

With the earths cry for help as pollution rate increases, researchers are faced with a common task of tackling pollution resulting from dependence on fossil fuel as well as delivering sustainable energy. Renewable energy resources such as solar, wind, hydro to mention a few are currently finding applications within the world energy mix but some limitations which range from meteorology of locations to expected maximum energy output attainable. Hydrogen, the most abundant element in the world stand chance of abating this problem. However conventional method of its producing, poses severe treat to the atmospheric environment with the release of oxides of carbon hence, referred as blue hydrogen. Contrarily, green hydrogen from human urine stands a more sustainable and environmentally friendly energy resource. This study was aimed to empirically model the synthesis of green hydrogen from urea in human urine by an electrolytic process. The synthesized hydrogen was characterized on physiochemical properties of conductivity, turbidity, pH, specific gravity and colour, while the precursor urine characterized on gender, exposure duration and storage temperature. The synthesis process was modelled using Microsoft excel solver for the overall cell energy or polarization curve model, the Faraday’s efficiency model and gas purity model at electrolyte concentrations of 25 wt./wt., 30 wt./wt. and 35 wt./wt. of potassium oxide (buffer} to urea over a five-temperature interval range of 45 to 85 oC. Findings revealed that the gas produced was 99.88% hydrogen at the cathode. Also, hydrogen produced increased with increase in electrolyte concentration and moderate temperature with optimal conditions at 35 w/w electrolyte concentration and 65 oC. However, the minimum cell voltage was 2.06 V at 85 oC and 35 w/w electrolyte concentration. With an exception of the Faraday’s efficiency model at 30 wt./wt. electrolyte concentration across the system’s operating temperature range yielding an R2 value of 0.711, all the models yielded coefficient of determination values in the range of 0.96 and 0.99, indicating good fit for the alkaline urine electrolysis for green hydrogen synthesis from human urine.