Electrolyte Solution Research Articles

Measurement of resistivity of biofluids in the presence of an electrical double layer

Abstract Detecting alterations in the electrical response of human biofluids can provide valuable information in the early stages on pathological conditions in a patient. Developing techniques for obtaining rapid information on the electrical resistivity of common ionic biofluids by non-invasive techniques can improve medicare through a rapid and more precise diagnosis. In this work, we analyze the use of an electrical device consisting of a cell formed of flat parallel steel plates to measure the resistivity of these substances. When the electrical cell is filled with a biofluid an electrical double layer (EDL) is formed on the electrodes/biofluid interface. Then, we measure the electrical response and examine the general conditions under which the EDL does not interfere with the assesment of the biofluid’s resistivity. The electrical response is analyzed in terms of an equivalent circuit model. Also, a simplified theoretical model of a suspension of biological cells considering spherical particles with a membrane is discussed to validate measurements and theoretically exhibit the contribution of the cell’s membrane to the effective resistivity. We present measurements of the resistance of the electrical cell filled with electrolyte solutions, blood plasma, and diluted suspensions of erythrocytes in a hypotonic solution. Results show that the resistance of the electrical cell is sensitive to the volume density of biological cells suspended between the parallel plate electrodes, producing a signal with a high signal to noise ratio. From the measured resistance of a suspension of erythrocytes in a isotoinc solution and the simplified theoretical model, we estimate the value of the conductivity of the interior of the erythrocytes. The results show that measured resistance varies with blood samples and hemolysis progression. The device's sensitivity to the number of erythrocytes passing between the electrodes makes it useful for measuring sedimentation kinetics.

Transport Numbers and Electroosmosis in Cation-Exchange Membranes with Aqueous Electrolyte Solutions of HCl, LiCl, NaCl, KCl, MgCl2, CaCl2 and NH4Cl

Electroosmosis reduces the available energy from ion transport arising due to concentration gradients across ion-exchange membranes. This work builds on previous efforts to describe the electroosmosis, the permselectivity and the apparent transport number of a membrane, and we show new measurements of concentration cells with the Selemion CMVN cation-exchange membrane and single-salt solutions of HCl, LiCl, NaCl, MgCl2, CaCl2 and NH4Cl. Ionic transport numbers and electroosmotic water transport relative to the membrane are efficiently obtained from a relatively new permselectivity analysis method. We find that the membrane can be described as perfectly selective towards the migration of the cation, and that Cl− does not contribute to the net electric current. For the investigated salts, we obtained water transference coefficients, tw, of 1.1± 0.8 for HCl, 9.2 ± 0.8 for LiCl, 4.9 ± 0.2 for NaCl, 3.7 ± 0.4 for KCl, 8.5 ± 0.5 for MgCl2, 6.2 ± 0.6 for CaCl2 and 3.8 ± 0.5 for NH4Cl. However, as the test compartment concentrations of LiCl, MgCl2 and CaCl2 increased past 3.5, 1.3 and 1.4 mol kg−1, respectively, the water transference coefficients appeared to decrease. The presented methods are generally useful for characterising concentration polarisation phenomena in electrochemistry, and may aid in the design of more efficient electrochemical cells.

Natural Organic Matter Stabilizes Pristine Nanoplastics but Destabilizes Photochemical Weathered Nanoplastics in Monovalent Electrolyte Solutions.

Photochemical weathering and eco-corona formation through natural organic matter (NOM) adsorption play vital roles in the aggregation tendencies of nanoplastics (NPs) in aquatic environments. However, it remains unclear how photochemical weathering alters the adsorption patterns of NOM and the conformation of the eco-corona, subsequently affecting the aggregation tendencies of NPs. This study examined the effect of Suwannee River NOM adsorption on the aggregation kinetics of pristine and photoaged polystyrene (PS) NPs in monovalent electrolyte solutions. The results showed that photochemical weathering influenced the conformation of the eco-corona, which, in turn, determined NP stability in the presence of NOM. Hydrophobic components of NOM predominantly bound to pristine NPs through hydrophobic and π-π interactions, and extended hydrophilic segments in water hindered NP aggregation via steric repulsion. Conversely, hydrogen bonding facilitated the binding of these hydrophilic segments to multiple photoaged NPs, thereby destabilizing them through polymer bridging. Additionally, the stabilization and destabilization capacities of NOM increased with its concentration and molecular weight. These findings shed light on the destabilizing role of NOM in weathered NPs, offering new perspectives on environmental colloidal chemistry and the fate of NPs in complex aquatic environments.

The Electroactive Species and Electrolyte Solution Chemistry Importance in Non-Aqueous Mg Electrochemical Systems

Abstract The chemistry of the electrolyte solutions that enable reversible Mg deposition is not trivial. Such solutions are currently limited to ethereal solvents and most of them contain chlorides complexes. These ionic complexes have important role in the performance. However, the presence of chlorides in these solutions complicates the cathode side because such solutions are not compatible with the commonly used metallic current collectors for cathodes. Consequently, it is questionable whether it is possible to synthesize fully functional Cl-free electrolyte solutions suitable commercial Mg-ion batteries. Noked et al. reported that by adding DME to the precursor electrolyte [Mg2Cl3*6THF]+ [Ph3AlCl]- in THF, it was possible to create a new electroactive complex Mg salt, namely, [Mg-3.DME]2+ 2[AlPh3Cl]-, which solution performs better than the precursor’s solution. This solution introduces a new case of chlorides free electrolyte solution, with stabilized Mg2+ cations and anions containing chloride ligands which cannot lead to corrosion phenomena. In this work a full evaluation of selected electrolyte solution was carried out, considering rigorously the role of the electroactive species and the anion complexes in the electrochemical process. 
In addition, we study the effect of the anion on the electrochemical performance by comparing this solution with other previously presented solutions.

Optimization of Capillary Electrophoresis by Central Composite Design for Separation of Pharmaceutical Contaminants in Water Quality Testing

Many pharmaceutical active compounds are prepared as hydrochlorides for quick release in the gastrointestinal tract upon oral administration. Their inadvertent escape into the water environment requires efficient analytical separation for accurate quantitation to monitor their environmental fate. The purpose of this study is to demonstrate how best to optimize a capillary electrophoresis method for the separation of four model pharmaceutical hydrochlorides. Concentration of sodium dibasic phosphate in the background electrolyte solution, pH adjustment with HCl or NaOH, and applied voltage across the capillary were the three key factors chosen for optimization. The peak resolutions and total migration time were examined as the response indicators to complete a central composite design in response surface methodology. The examination revealed that CE separation was driven significantly by a linear regression model and minimally by a quadratic regression model, based on the coefficient of determination, the lack of fit, the total sum of squares, and the p values. Under optimal conditions of the background electrolyte concentration of 75 mM, pH 9, and the applied voltage of 10 kV, the model hydrochlorides were separated within five minutes in the migration order of metformin (first) > phenformin > mexiletine > ranitidine (last). The limits of UV detection/quantification attained under optimal CE conditions were 0.015/0.045, 0.020/0.060, 0.142/0.426, and 0.017/0.051, respectively.

Starting Electroosmosis in a Fibrous Porous Medium with Arbitrary Electric Double-Layer Thickness

The transient electroosmotic response in a charged porous medium consisting of a uniform array of parallel circular cylindrical fibers with arbitrary electric double layers filled with an electrolyte solution, for the stepwise application of a transverse electric field, is analyzed. The fluid momentum conservation equation is solved for each cell by using a unit cell model, where a single cylinder is surrounded by a coaxial shell of the electrolyte solution. A closed-form expression for the transient electroosmotic velocity of the bulk fluid in the Laplace transform is obtained as a function of the ratio of the cylinder radius to the Debye screening length and the porosity of the fiber matrix. The effect of the fiber matrix porosity on the continuous growth of the electroosmotic velocity over time is substantial and complicated. For a fiber matrix with larger porosity, the bulk fluid velocity takes longer to reach a certain percentage of its final value. Although the final value of the bulk fluid velocity generally increases with increasing porosity, early velocities may decrease with increasing porosity. For a given fiber matrix porosity, the transient electroosmotic velocity is a monotonically increasing function of the ratio of the cylinder radius to the Debye length.

Dynamic electroosmotic flow and solute dispersion through a nanochannel filled with an electrolyte surrounded by a layer of a dielectric and immiscible liquid.

The present article deals with the modulation of oscillatory electroosmotic flow (EOF) and solute dispersion across a nanochannel filled with an electrolyte solution surrounded by a layer of a dielectric liquid. The dielectric permittivity of the liquid layer adjacent to supporting rigid walls is taken to be lower than that of the electrolyte solution. Besides, the aforesaid liquid layer may bear additional mobile charges, e.g., free lipid molecules, charged surfactant molecules etc., which in turn lead to a nonzero charge along the liquid-liquid interface. Such a layer of a dielectric liquid resembles the membrane of various biological cells. An AC voltage is applied to generate the fluid motion. Note that among others, the major advantage of AC voltage is that it can suppress the formation of gas bubbles that are often very detrimental in flow through microdevices. Considering the combined impact of ion partitioning and ion steric effects, we have studied the EOF modulation and its impact on the dispersion of the solute band of given width placed initially at the middle of the channel. The full scale numerical results for flow modulation induced by an AC electric field and its impact on the solute transport are presented considering a wide range of pertinent parameters. It is observed that the molar concentration of additional charge present in the dielectric liquid layer and its thickness, interfacial charge, and concentration of the bulk electrolyte, ion partitioning and ion steric effects, frequency of oscillatory electric field, channel height etc., have a substantial impact on the flow modulation, effective dispersion coefficient as well as broadening of the solute band across the channel. We have further highlighted the impact of the Péclet number on the transport and dispersion of solutes. Along with the numerical results, several benchmark analytical results under various limits are deduced for electrostatic potential, flow velocity and various quantities associated with the dispersion process.

Photoaging-induced variations in heteroaggregation of nanoplastics and suspended sediments in aquatic environments: a case study on nanopolystyrene

Photoaging of nanoplastics (NPs) and heteroaggregate with suspended sediments (SS) determines transport processes and ecological risks of NPs in aquatic environments. This study investigated the disruption of photoaging on the heteroaggregation behavior of polystyrene NPs (PSNPs) and SS in different valence electrolyte solutions and deduced the interaction mechanisms by integrating aggregation kinetics and molecular dynamics (MD) simulation. Increasing the electrolyte concentration significantly enhanced the heteroaggregation between PSNPs and SS, and the divalent electrolytes induced the heteroaggregation more efficiently. MD simulation at the molecular level revealed that PS and SS could spontaneously form clusters, and photoaged PS has a stronger potential to fold into a dense state with SS. Photoaging for 30 d retarded heteroaggregation due to the steric hindrance produced by the leached organic matter in NaCl solutions, and the critical coagulation concentration (CCC) increased by more than 85.44%. Contrarily, photoaging caused more oxygen-containing functional groups produced on the surface of PSNPs through Ca2+ bridging promoting heteroaggregation and thus destabilizing in CaCl2 solutions, the CCC decreased by 23.53% ∼ 35.29%. These findings provide mechanistic insight into the environmental process of NPs and SS and are crucial for a comprehensive understanding of the environmental fate and transport of NPs in aquatic environments.

Balanced Electrolyte Solutions Versus 0.9% Saline for Kidney Transplantation: An Updated Systematic Review and Meta-analysis.

Perioperative intravenous fluids are administered to kidney transplant recipients to maintain hemodynamic stability and graft perfusion; however, the ideal fluid remains uncertain. Although 0.9% saline (saline) is commonly used, its high chloride content causes hyperchloremic metabolic acidosis and may increase the risks of delayed graft function (DGF) and hyperkalemia. Balanced electrolyte solutions (BES) have a more physiological chloride concentration and may reduce these risks. Previous meta-analyses found insufficient evidence to compare BES with saline for these outcomes; however, new studies have recently been published. In this updated review, we compared the effects of BES with saline on the risk of DGF and hyperkalemia in kidney transplantation. MEDLINE, Embase, and CENTRAL were searched for randomized controlled trials comparing BES with saline in kidney transplantation. The primary outcomes were DGF and hyperkalemia. Eligible studies were assessed for risk of bias and data were pooled for analysis. The Grading of Recommendations Assessment, Development, and Evaluation framework was used to assess the quality of evidence. Ten studies involving 1532 participants were included. The quality of evidence was high for deceased donor transplantation and very low for living donor transplantation. The relative risk (RR) of DGF associated with BES compared with saline was 0.83 (95% confidence interval [CI], 0.71-0.96; P = 0.01) in deceased donor transplantation. There was no difference in DGF in living donor transplantation (RR 0.79; 95% CI, 0.26-2.41; P = 0.68). There was no difference in hyperkalemia between groups (RR 0.87; 95% CI, 0.59-1.27; P = 0.46). Compared with saline, BES reduces the risk of DGF in deceased donor kidney transplantation without increasing hyperkalemia.

Dual-channel nano-carbon-liquid/liquid junction electrodes for multi-modal analysis: redox-active (dopamine) and non-redox-active (acetylcholine).

We present here a dual-channel nanoelectrode to detect both redox-active and non-redox-active analytes. The dual-channel nanoelectrode was developed from theta nanopipette. We developed one channel of the theta nanopipette to be a carbon nanoelectrode and the other channel to be a nano interface between two immiscible electrolyte solutions (nanoITIES) electrode, producing a nano-carbon-ITIES platform. The carbon nanoelectrode channel was developed by carbon deposition via pyrolysis followed by focused ion beam milling to measure redox-active analytes. The nanoITIES electrode channel was developed to detect non-redox-active analytes. The nano-carbon-ITIES electrodes were characterized using electrochemistry, scanning electron microscopy and transmission electron microscopy. Dopamine (a redox-active analyte) and acetylcholine (a non-redox-active analyte) were measured on the dual-channel nano-carbon-ITIES platform using the carbon nanoelectrode and the nanoITIES electrode, respectively. Using cyclic voltammetry, the diffusion-limited current of dopamine and acetylcholine detection on the nano-carbon-ITIES electrode increased linearly with increasing their concentrations. Using chronoamperometry (current versus time), we showed that the nano-carbon-ITIES electrode detected acetylcholine and dopamine at the same time. The introduced first-ever dual-functional nano-carbon-ITIES electrodes expand the current literature in multi-channel electrodes for multi-purpose analysis, which is an emerging area of research. Developing the analytical capability for the simultaneous detection of acetylcholine and dopamine is a critical step towards understanding diseases and disorders where both dopamine and acetylcholine are involved.

Corrosion Behaviour of Cu-Plate Current Collector under Ex-situ Cyclic Stability Testing for Energy Storage Application

This study compares the corrosion behaviour of a copper plate current collector subjected to an ex-situ cyclic stability test in a 6M KOH and a 6M Na2SO4 electrolyte solution for an electrochemical supercapacitor cell. Through experimental analysis, the change in microstructures resulting from the corrosion behaviour of the copper plate current collector samples are examined by employing various analytical techniques, including microscopy, spectroscopy, and surface roughness analyzer. The corrosion behaviour was studied by employing potentiodynamic polarization and electrochemical impedance spectroscopy analyses. The copper plate current collector samples analysed in 6M KOH and 6M Na2SO4 electrolyte solution showed uniform and localized corrosion product formation, respectively. The CU-72HRS sample recorded a corrosion potential of -608.6mV, -628.87mV, and -89.5mV, -87.588mV using both Tafel and resistance polarization data fitting analysis, respectively, for both 6M KOH and 6M Na2SO4 electrolyte solution using a scan rate of 5mV/s at a voltage window of -1 to 1V. Comparing the microstructural changes under various cyclic conditions provides valuable insights into the durability and reliability of copper plates as current collectors in energy storage systems. The results of this study help improve our understanding of the supercapacitor cell performance in ex-situ cyclic stability tests, assisting in the development of more efficient and durable energy storage technologies.

Organic redox flow batteries in non-aqueous electrolyte solutions.

Redox flow batteries (RFBs) are gaining significant attention due to the growing demand for sustainable energy storage solutions. In contrast to conventional aqueous vanadium RFBs, which have a restricted voltage range resulting from the use of water and vanadium, the utilization of redox-active organic molecules (ROMs) as active materials broadens the range of applicable liquid media to include non-aqueous electrolyte solutions. The extended voltage range of non-aqueous media, exceeding 2 V, facilitates the establishment of high-energy storage systems. Additionally, considering the higher cost of non-aqueous solvents compared to water, the objective in developing non-aqueous electrolyte solution-based organic RFBs (NRFBs) is to efficiently install these systems in a compact manner and explore unique applications distinct from those associated with aqueous RFBs, which are typically deployed for grid-scale energy storage systems. This review presents recent research progress in ROMs, electrolytes, and membranes in NRFBs. Furthermore, we address the prevailing challenges that require revolution, encompassing a narrow cell voltage range, insufficient solubility, chemical instability, and the crossover of ROMs. Through this exploration, the review contributes to the understanding of the current landscape and potential advancements in NRFB technology and encourages researchers and professionals in the energy field to explore this emerging technology as a potential solution to global environmental challenges.

Synthesis and characterization of graphene-based electrocatalysts for the detection of damaged starch ratio

In this study, the detection of damaged starch ratio on synthesized graphene-based electrocatalysts were evaluated based on the iodine oxidation mechanism. Electrocatalysts were synthesized by three different electrochemical exfoliation techniques. Synthesized catalysts were tested in a three-electrode system with electrolytes mixed with flours at different damaged starch ratios (at 16.5, 25 and 30 UCD values). For the electrochemical tests related to iodine absorption, electrolyte solutions were prepared according to Medcalf and Gilles principle; cyclic voltammetry and chronoamperometry were performed at 50 mV/s in the range of 0–1 V vs. SCE; and at a potential of 1 V vs. SCE. The synthesized catalysts showed reversible reaction properties by giving anodic and cathodic peaks of iodine in the three-electrode system. The exfoliated graphene samples were characterized via standard tools such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman and UV-vis spectroscopy. After all, it was seen that the G2 type electrocatalyst has the highest sensitivity to iodine absorption and potential for use in damaged starch detection.

Electrocatalytic Reduction of Nitrate to Ammonia in an Aqueous Environment Using Nanoporous N- and P-Enriched Carbonaceous Material.

Carbonization (Argon atmosphere, 900 °C, 2 h) of heteroatom-enriched pyridine-bridged inorganic-organic hybrid material (HPHM) resulted in the formation of a high specific surface area (SABET of 1080 m2 g-1) carbonaceous material designated as HPHMC900. The HPHMC900 serves as an effective electrocatalyst for the reduction of nitrate in an aqueous environment to ammonia (NO3RR). Importantly, HPHMC900 demonstrated fast kinetics for the NO3RR with a low Tafel slope of 70 mV decade-1. An NH3 production yield of 21 μg h-1 mgcat-1 was obtained with a Faradaic efficiency (FE) of 88.3% at -0.4 V in a 0.1 M KNO3 electrolytic solution. The high double layer capacitance (Cdl) of 14.1 mF cm-2 corroborates high SABET and exposed active sites of HPHMC900. The maximum FEs were estimated to be 48%, 93%, and 98%, corresponding to 0.05, 0.5, and 1.0 M KNO3 with maximum NH3 production yields of 18.7, 22.1, and 39.0 μg h-1 mgcat-1, respectively. The potential of employing HPHMC900 for the NO3RR as an electrocatalyst is evident by its robust stability, high SABET, and enrichment with heteroatoms N (7.7%) and P (0.28%). Thus, this sustainable environmentally benign strategy can be used for the treatment of pollutant NO3- to produce NH3.

Effectiveness of Balanced Electrolyte Solution vs Normal Saline in the Resuscitation of Adult Patients with Diabetic Ketoacidosis: An Updated Systematic Review and Meta-analysis.

Fluid resuscitation is the first-line treatment for patients with diabetic ketoacidosis (DKA). However, the optimal choice of resuscitative fluid remains controversial. This study aims to evaluate the impact of balanced electrolyte solution (BES) compared to 0.9% sodium chloride (NS) on various physiological and clinical outcomes in adult DKA patients. An extensive search of electronic databases, including Embase, PubMed, Cochrane Library, Web of Science, and Google Scholar, was conducted to select studies that directly compared BES and NS in adult DKA patients. This systematic review and meta-analysis included nine studies, comprising both randomized controlled trials and retrospective studies. Combined estimates were expressed as mean differences (MDs) with 95% confidence intervals (CIs). The primary outcomes were time to resolution of DKA and length of hospital stay. The secondary outcomes were post-resuscitation chloride and bicarbonate levels and adverse events. No significant difference was observed between BES and NS in the time to DKA resolution (MD: -1.63; 95% CI: -7.66-4.41; p = 0.60) or length of hospital stay (MD: -0.07; 95% CI: -0.44-0.31; p = 0.73). However, BES resulted in significantly higher post-resuscitation bicarbonate levels (MD: 1.63; 95% CI: 0.86-2.39; p < 0.001) and lower post-resuscitation chloride levels (MD: -2.37; 95% CI: -3.56 to -1.19; p < 0.001). The use of BES is associated with improved post-resuscitation electrolyte balance and preventing hyperchloremic metabolic acidosis in DKA patients. While BES may offer some biochemical advantages, both BES and NS are safe for treating DKA. Gupta P, Nasa P, Shahabdeen SM. Effectiveness of Balanced Electrolyte Solution vs Normal Saline in the Resuscitation of Adult Patients with Diabetic Ketoacidosis: An Updated Systematic Review and Meta-analysis. Indian J Crit Care Med 2025;29(1):65-74.

IMPROVES CRITICAL THINKING SKILLS AND SELF-EFFICACY OF LEARNERS USING THE PJBL-STEAM MODEL IN WETLAND CONTEXTS

Critical thinking skills are one of the essential thinking skills mastered in the 21st century for the progress of a nation. They can help a person to solve problems by interpreting, analyzing, evaluating, and inferring. Self-efficacy is a person's belief in his ability to solve problems. The ability to think critically is related to self-efficacy. The PjBL-STEAM model is one of the alternatives that seek to improve student’s critical thinking and self-efficacy skills. The wetland context referred to in this study uses a solution of fruits that can live in wetlands as one of the learning media on electrolyte and nonelectrolyte solution materials. This study aims to examine the improvement of critical thinking and self-efficacy of students through the use of the PjBL-STEAM learning model in wetland contexts by comparing pretest and posttest values. This research model is quasi-experimental with a one-group pretest-postest research design. This study was conducted at SMAN 3 Barabai with a study population of class X MIA, and the sample taken purposively was 25 students of class X MIA 3. Data collection using tests and questionnaires. Data analysis was carried out by comparing pretest and posttest values. The results showed that the PjBL-STEAM learning model in the wetland context could improve the critical thinking skills and self-efficacy of students with an N-gain value of critical thinking ability of 0.58 (moderate category) and N-gain self-efficacy of 0.75 (high category). In other words, using PjBL-STEAM in wetland contexts is stated to be effective for improving students' critical thinking skills and self-efficacy.

Investigation of Influencing Factors on Power Generation Performance in Reverse Electrodialysis

The importance of meeting energy demands from renewable sources is growing daily. Reverse electrodialysis (RED) is a membrane-based technology that produces energy using electrolyte solutions with different salinities. This study has generated energy from the RED system using the commercial Fujifilm Type II ion exchange membranes (IEMs). Many parameters affect the power generation performance of the RED system. This study systematically investigated the parameters, the presence of divalent ions and organic molecules, the electrolyte solution concentration, and the flow velocity. The flow velocity results indicated that energy efficiency increased with increasing flow velocity of the electrolyte solutions. The presence of divalent ions created uphill transport. The results showed that increasing the mole ratio of divalent ions in the feed electrolyte solutions dramatically decreased the RED system performance due to increasing resistances. The organic fouling test of the anion exchange membranes (AEMs) was carried out using a real humic and fulvic acid mixture under static conditions. The results indicated that fouling layers formed in the AEMs structure, and these layers decreased by 30% of RED performance. Lastly, the RED system's long-term performance was tested for 4 hours at a constant current density of 8 A/m2 before and after AEM fouling experiments. The results revealed the fouling layers severely reduced the power generation performance of the RED system.

In situ electrosynthesis, optimization and stability of AgNPs within chitosan: pullulan polymeric network

Abstract In this study, a systematic investigation to achieve a deeper understanding of the synergistic effect of chitosan (CS) and pullulan (PL) as a polymeric matrix on the in situ electrosynthesis AgNPs under applied voltage 1.5 V for 2 h. The process was applied using CS: PL blend with different ratio as electrolytic solution, reducing, and stabilizing agent avoiding using toxic reducing agent, byproduct of the reaction, controlling AgNPs size and stability. Investigation of the samples using UV–visible spectroscopy (UV–vis), Inductively coupled plasma optical emission spectroscopy (ICP), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis (TG) revealed that AgNPs successfully formed under controlling the size and stability. Across all ratios except using only PL as an electrolyte, the results revealed the occurrence [chitosan/pullulan] Ag+ complex band at around 250 nm and a localized peak at 420 nm attributed to the SPR of AgNPs. TEM confirmed AgNPs formation with decreasing in size and increasing in concentration as a function of increasing CS content. Findings obtained by quantifying the concentration of silver using ICP whereas the concentration of CS is raised, the concentration of silver liberated increases. Zeta potential revealed that AgNPs have a positive surface charge maximized with increasing CS content. Furthermore, stability against aging for 2 months at 4o C revealed that the addition of PL to CS matrix works on increasing the stability of AgNPs against aging.

Evaluation of Corrosion Potential Stability of Stainless Steels in Dilute Electrolyte Solution for Application to a Quasi-Reference Electrode Used in Electrochemical Sensing System

To evaluate the long term corrosion potential stability of stainless steel (SS) in environmental water, the corrosion potential of SUS304, SUS316, SUS316L, and SUS430 was measured for 1 week in a solution of 0.9 mM NaHCO3 and 0.5 mM CaCl2, referred to as “sub-tap water.” The potential of the SSs upon initial immersion in sub-tap water was approximately 10 times less stable than the potentials of Fe and Cu. However, as immersion continued, the stability of the corrosion potential of the SS improved and became equivalent to those of Fe and Cu. The stability could be manipulated by pretreatment (pre-immersion) before samples were immersed in sub-tap water. The stability was increased by pre-immersion in an acidic solution but was reduced by a passivation treatment. The formation of iron oxides on the SS surface stabilized the potential, whereas surface enrichment with Cr led to instability. This behavior can also be inferred from a comparison of the polarization curves, where the passive current after the passivation treatment was the largest. This result is also speculatively attributed to the corrosion potential in sub-tap water decreasing over time after the passivation treatment. The charge transfer resistance likely contributes significantly to the potential stability, as indicated by an equivalent circuit analysis based on electrochemical impedance spectroscopy. The results showed that, when stabilizing the corrosion potential of SS, there is no need to reduce the charge transfer resistance as with existing reference electrodes. Stability is achieved when the surface thickness is such that the pseudo-capacitance in a dilute solution is less than 10 µF sα−1cm−2 and potential stability does not influence a few changes in the CPE1 value after potential stability is achieved. The results of this study show that SS can be used as a quasi-reference electrode material. We expect the findings presented herein to strongly affect the development of electrochemical sensors that can be easily used in long term continuous measurements and in situ applications.

Potential of Tebalan Shells from Tuban Beach as Active Material in Perovskite Solar Cells

One source of environmentally friendly renewable energy that has begun to be widely developed is PSC (Perovskite Solar Cell) made from natural ingredients. PSC is a new breakthrough strategic mineral processing technology as an alternative to silicon in the industry of solar power safety and stability. PSCs are easier to manufacture compared to silicon-based solar cells. The PSC material in this research is perovskite CaTiO3 which is made from the reaction between calcium carbonate (CaCO3) which is obtained from the Tebalan shell powder of Tuban beach and titanium dioxide (TiO2). The method used in this research is substrate preparation, synthesis of Perovskite CaTiO3, making TiO2 paste2, electrolyte solution preparation, counter electrode preparation, fabrication perovskite solar cell (PSC), as well as testing, characterization and data analysis. The tests and characterization that will be carried out are: Crystal structure of powdered materials used in making perovskite solar cells using XRD (X-ray Diffractometer) type X-Pert3 Powder, testing electric current with a potentiometer, and measuring light with a lux meter. The results of XRD testing on the calcined powder showed that the structure of calcium titanate perovskite (CaTiO3) was as much as 68.2%. Meanwhile, the characteristic values ​​of the electrical properties of Tebalan clam shell perovskite solar cells from the lamp light source data obtained show that Vm and Im Daylight lamps have a greater value than warm white lamps and the efficiency value of the solar light source is highest when shown Air Mass 1.5, which is 0.000127%.