Publication Date: 2023
Energy (0360-5442)263
Open-cathode polymer membrane fuel cells (PEMFCs) uses air as both oxidant and coolant to maintain the required water content of the membrane for stable operation. In this work, the performance of a new strategy for improving cooling in open-cathode PEMFC is assessed and benchmarked against the conventional open-cathode PEMFC under similar operating conditions. With high air stoichiometry on the cathode side, air serves as both an oxidizer and a cooling medium, unlike conventional fuel cells, where cooling channels are installed separately. In order to compare two fuel cell cooling systems accurately, it is necessary to model electrochemical and thermal simulations simultaneously. A three-dimensional multiphase model is developed and results show that embedding separate cooling channels in PEMFC enhances cooling and stabilizing proton transfer across the membrane. While the conventional open-cathode PEMFC revealed lower losses in the polarization curve's activation and concentration loss zones. The case with additional cooling channels exhibited lesser losses in the ohmic zone. Although the difference in maximum output power at 0.65 V voltage reached 6.3 W for the case with additional cooling channels, the parasitic load due to the pressure drop in this fuel cell is 0.34 W, higher than the conventional fuel cell obtained at 0.03 W. © 2022 Elsevier Ltd
Publication Date: 2022
Energy Conversion and Management (0196-8904)268
One of the challenges to increase the life and improve the performance of the proton exchange membrane fuel cell (PEM) fuel cell is to use an appropriate cell cooling method. Proper cooling is important in maintaining a uniform temperature distribution and preservation of membrane water content to in order to prevent local hot spots and for high cell performance. In this work, three-dimensional multiphase numerical models of proton exchange membrane fuel cells using active (liquid cooling) and passive (heat pipes) cooling methods have been developed, wherein a heat pipe model was first simulated by simulink to determine the heat extraction capacity of the heat pipe. A 4-way serpentine flow field was employed as the typical flow field for gas channels and cooling channels. The results show that the use of heat pipe cooling, in addition to maintaining high water content and thus reducing membrane resistance and increasing cell performance, imposes less parasitic load on the cell power generation system than water cooling. © 2022 Elsevier Ltd
Ghaedamini m., ,
Baharlou-houreh, N.,
Afshari, E.,
Shokouhmand h., ,
Jahantigh, N. Publication Date: 2022
International Journal of Hydrogen Energy (03603199)47(38)pp. 17010-17021
In the present study, a membrane-based air-to-air planar humidifier (MAPH) with baffle-blocked flow channels and a common MAPH are fabricated, tested and compared. These MAPHs are well thermal insulated from their surroundings. Polyoxymethylene (POM) plates with some unique properties such as large tensile and flexural strength, high chemical resistance and high stiffness are used to create channels at dry and humid sides of MAPHs. The obtained findings revealed that the higher heat and water transfer rates and smaller dew point approach temperature (DPAT) in entire tested flow rates occurs in baffle-blocked MAPH. To evaluate the MAPH performance with considering the pressure drop, a dimensionless parameter, performance evaluation criteria (PEC), is introduced. At flow rates less than 1 m3/h, PEC is less than 1, indicating a decline in MAPH performance with considering the pressure drop. In baffle-blocked MAPH using water trap in the inlet of dry side leads to the performance deterioration. Additionally, the increased relative humidity (RH) of humid side inlet causes an increase in DPAT, consequently, the performance deterioration. © 2022 Hydrogen Energy Publications LLC
Publication Date: 2022
Journal of Energy Storage (2352152X)47
Due to the limitations with fossil fuels consumption, it is necessary to pay more attention to clean energy sources such as solar energy. Using solar energy systems as a driven of hybrid systems and integrating with an energy storage technology can alleviate some of the problems. In the present paper, a novel solar driven-polygeneration energy system with electrical energy storage is introduced and investigated. The cycle power generation section is composed of parabolic trough collector field, proton-exchange membrane fuel cell, organic Rankine cycle, alkaline electrolyzer, and thermoelectric generator. The light energy of the sun is converted into thermal energy by the solar collector. This thermal energy prepares the necessary thermal duty of the organic Rankine cycle's evaporator. Then, the electricity generated by the organic Rankine cycle is used to electrify an electrolyzer. The oxygen and hydrogen obtained from electrolyzer are used to generate power and heat by the fuel cell. Then, the waste heat of the fuel cell goes to the hot end of the thermoelectric generator and electricity is generated. The electricity generated from the fuel cell, thermoelectric generator, and surplus of the organic Rankine cycle is stored via a hybrid storage system for times of need (at night, cloudy days and/ or peak consumption hours). Findings revealed that the proposed polygeneration cycle is capable of generating 22.5 kW of power. Furthermore, 140.8 kW of thermal power and 97.3 g/h of hydrogen fuel are generated by the solar collector field and electrolyzer, respectively. Moreover, sum exergy destruction, system efficiency, and net capacity of the storage system are 18.83 kW, 60.3%, and 89 m3, respectively. Three different scenarios are considered for the solar field design based on the determined collector numbers. © 2021
Publication Date: 2022
International Journal of Energy Research (1099114X)46(2)pp. 1481-1496
Fuel cells today have a variety of applications, such as fueling vehicles, which lead to a reduction in conventional fuel consumption and environmental pollution. On the other hand, in the present era, unmanned aerial vehicle (UAV) is known as one of the most important unmanned systems for delivering postal packages, environmental monitoring, disaster relief, and military target. However, the performance of fuel cells is affected by their operating pressure and temperature. In addition, due to some political and technical considerations, the performance of these systems (especially UAV based on fuel cells) is very rare in the literature. The present work provides a conceptual design of UAV propulsion system based on a fuel cell system and a battery. The performance of two different fuel cells, namely the alkaline fuel cell (AFC) and proton exchange membrane fuel cell (PEMFC), is examined separately and compared. Mission and constraint analyses of the system, as well as weight distribution of UAV, are provided. Furthermore, the performance of the UAV propulsion system in different flight modes and the performance of fuel cells under atmospheric conditions are discussed. It should be noted that reference UAV data are used for input parameters. It was found that the total power required by the UAV to carry out the mission is equal to 1253.7 W, which the share of takeoff, climb, cruise, and maximum speed flight modes were 321.3, 608.5, 118.3, and 205.6 W, respectively. Furthermore, the UAV under study, in this paper, has flight endurance of about 7.4 hours. Also, the required area of the PEMFC and AFC to supply the UAV power under the study conditions is about 0.03 and 0.6 m2, respectively. Finally, it observed that with increasing altitude (in the absence of a heating system) the performance of both fuel cells is greatly reduced. © 2021 John Wiley & Sons Ltd.
Afshari, E.,
Khodabakhsh s., ,
Jahantigh, N.,
Toghyani, S. Publication Date: 2021
International Journal of Hydrogen Energy (03603199)46(19)pp. 11029-11040
To improve proton exchange membrane (PEM) electrolyzes’ performance the voltage loss through them should be avoided. In this work, it is intended to analyze losses including of diffusion loss, ohmic loss due to electrode, bipolar plate (BP), and membrane resistances, and gas crossover associated with the water transferring mechanisms. All of the losses are associated with water transferring mechanisms, which is created due to electro-osmoic drag, pressure differential between the anode and cathode sides, and diffusion. Furthermore, the effect of membrane thickness, cathode pressure, and operating temperature on the hydrogen crossover is examined. In addition, the contribution of ohmic loss due to electrode bipolar plate (BP), and membrane resistances is studied and, the contribution of different losses on the cell performance is discussed. Results show that raising cathode pressure from 1 to 40 bar lead to the increment of anodic hydrogen content from 1.038% to 21% at the specific current density of 10,000 A/m2. Enhancing the thickness of membrane has considerable impact on decrementing anodic hydrogen content, but the mass transfer loss rises from 0.022 to 0.027 V with enhancing membrane thickness from 50 to 300 μm, respectively. Furthermore, the contribution of voltage losses, assigned to each of losses are equal to 85%, 3%, and 12% for activation, diffusion and ohmic losses, respectively. It is found that, from the reported contribution for ohmic loss, the contribution of electrode BP, and membrane resistances are 31% and 69%, respectively. © 2020 Hydrogen Energy Publications LLC
Baharlou-houreh, N.,
Afshari, E.,
Shokouhmand h., ,
Asghari, S. Publication Date: 2020
Journal of Energy Storage (2352152X)29
In the present study, a three dimensional numerical simulation is performed to investigate the heat and water transfer enhancement in a polymer membrane humidifier with partially blocked channel. The experimental tests are also conducted for validation purposes. The thermal-hydraulic performance factor (JF) is introduced as the main parameter to evaluate the humidifier performance with considering pressure drop. The higher value of JF indicates the higher heat transfer with the lower pressure drop. When there are equal mass flow rates at both wet and dry sides, three ranges of flow rates are identified. At low flow rates (less than 4.4 mg/s), with and without considering pressure drop, the blocked humidifier shows weaker performance than the simple humidifier, so blocking is not recommended under any circumstances. At moderate flow rates (between 4.4 mg/s and 6.65 mg/s), regardless of pressure drop, the performance of the blocked humidifier is better than that of the simple humidifier, and with considering the pressure drop, the blocked humidifier performs weaker. At high flow rates (greater than 6.65 mg/s), with and without considering pressure drop, the blocked humidifier performs better than the simple humidifier. The same trend holds for the case of constant dry side flow rate with the variable wet side flow rate. © 2020 Elsevier Ltd
Publication Date: 2020
Renewable Energy (0960-1481)150pp. 840-853
In Afghanistan, more than 60% of the population does not have access to a reliable source of electrical energy. A thermo-economic analysis is conducted to compare the performance of a Photovoltaic (PV), Central Tower Receiver (CTR) plant and a Parabolic Trough Collector (PTC) plant with and without storage for the city of Herat, in Afghanistan. The nominal capacity of both plants is 110 MWe. The PTC plant with energy storage has the highest efficiency of about 43% that is approximately 50% more than the PV plant, however, the PV plant has more uniform power production profile. The output power of PTC with energy storage is 25% more than output power of PTC without energy storage and output power of CTR plant is half of PTC plant with energy storage. The Levelized Cost of Electricity (LCOE) is 0.146 $/kWh for CTR plant, 0.063 $/kWh for PV plant, 0.1076 $/kWh for PTC plant with energy storage, 0.104 $/kWh for PTC plant without storage and 0.12 $/kWh for PTC plat without storage and without backup fossil fuel systems. Increase of incentive by 10% leads to decrease of LCOE by about 20% for PTC and 13% for PV and 12% for CTR power plants. © 2020 Elsevier Ltd
Baharlou-houreh, N.,
Ghaedamini m., ,
Shokouhmand h., ,
Afshari, E.,
Ahmaditaba a.h., A.H. Publication Date: 2020
International Journal of Hydrogen Energy (03603199)45(7)pp. 4841-4859
In this study on humidifiers for polymer electrolyte membrane (PEM) fuel cell application, the experimental outcome of two air-to-air planar membrane humidifiers with three different internal flow patterns including cross, parallel and counter flows are investigated under isothermal and insulated boundary conditions. At all temperatures and flow rates, the conditions of higher performance, corresponding to highest water recovery ratio (WRR) and lowest dew point approach temperatures (DPAT), are encountered in the counter flow case, in contrary to the cross flow configuration. The insulation condition with dry inlet temperature at 30 °C and wet inlet temperature at 60 °C has a higher WRR index compared to isothermal condition at 60 °C but is lower than isothermal condition at 30 °C. The DPAT in humidifier with insulation condition is approximately equal to that obtained in isothermal condition at 60 °C but is much higher than what results in isothermal condition at 30 °C. It can be deduced that the temperature of the wet side inlet plays a key role in the humidifier performance. © 2019 Hydrogen Energy Publications LLC
Publication Date: 2019
International Journal of Hydrogen Energy (03603199)44(60)pp. 31731-31744
In this paper, a finite volume numerical method is developed to investigate a high temperature polymer exchange membrane (PEM) electrolyzer cell using a three-dimensional and non-isothermal model. The results that are obtained for the single cell are generalized to a full stack of electrolyzer and an exergoeconomic analysis is performed based on the numerical data. The effects of operating temperature, the pressure of cathode, gas diffusion layer (GDL) thickness, and membrane thickness on the energy and exergy efficiencies and exergy cost of the electrolyzer are examined. This study reveals that by increasing the working temperature from 363 K to 393 K, the exergy cost of hydrogen decreases from 23.16 $/GJ to 22.39 $/GJ, and the exergy efficiency of PEM electrolyzer stack at current density of 10,000 A/m2 increases from 0.56 to 0.59. The results indicate that increase of pressure deteriorates the system performance at voltages below 1.4 V. It is concluded that operation of the electrolyzer at higher pressures results in decrease of the exergy cost of hydrogen. Increase of membrane thickness from 50 μm to 183 μm leads to increase of the exergy cost of hydrogen from 23.24 $/GJ to 35.99 $/GJ. © 2019 Hydrogen Energy Publications LLC
Publication Date: 2019
International Journal of Hydrogen Energy (03603199)44(57)pp. 30420-30439
In this study, the numerical models are developed to investigate the influence of obstacle shape and number on performance of a planar porous membrane humidifier for proton exchange membrane fuel cell (PEMFC) application. Dew point of dry side outlet and water transfer rate are applied as evaluation parameters of the performance regardless of pressure drop. A dimensionless number named performance evaluation criteria (PEC) is calculated for all models. The higher value of PEC indicates the higher heat transfer rate with lower pressure drop. In humidifier with one rectangular obstacle compared with the simple humidifier, water transfer rate increases by 7.28%. The highest values of water transfer rate, dew point and PEC, also the greatest values of pressure drop are in humidifiers with rectangular, triangular and circular obstacles, in that order. When there is restriction in securing pumping power in fuel cell system, circular obstacle is the best choice. With considering the pressure drop, using one obstacle does not offer any advantage because the PEC is less than one (0.898). At least two obstacles are needed to have PEC number greater than one, consequently an efficient performance. An increment in number of obstacles causes an increment in water transfer rate, dew point and PEC. © 2019 Hydrogen Energy Publications LLC
Toghyani, S.,
Afshari, E.,
Baniasadi, E.,
Shadloo m.s., M.S. Publication Date: 2019
Renewable Energy (0960-1481)141pp. 1013-1025
A nanofluid is used as working fluid in a solar parabolic trough collector (PTC) for solar cooling and hydrogen production. The combined system is composed of five sub-systems including PTC, Rankine cycle, thermal energy storage, triple effect absorption cooling system (TEACS), and proton exchange membrane (PEM) electrolyzer. The results of the thermodynamic model for the hybrid PTC/Rankine cycle, TEACS and PEM electrolyzer subsystem are validated. Furthermore, the effects of ambient temperature, solar irradiation and nanofluid volume fraction on the hydrogen production, COP and exergy efficiency of TEACS, and the overall energy and exergy efficiency of the hybrid system are examined. We found that the rate of hydrogen production increases at higher solar radiation intensity because the Rankine cycle delivers more power to the PEM electrolyzer. Exergy analysis reveals that the efficiency of the hybrid system increases approximately by 9% by increase of ambient temperature from 5 to 40 °C. The power generation by Rankine cycle and hydrogen production by electrolyzer increases using higher volume fraction of nanoparticles. The overall energy and exergy efficiency of the hybrid system with the nanoparticles volume fraction of 0 are 1.55 and 1.4 times more than the nanoparticles volume fraction of 0.03 at solar intensity of 600 W m−2. © 2019 Elsevier Ltd
Atyabi, S.A.,
Afshari, E.,
Wongwises, S.,
Yan, W.,
Hadjadj, A.,
Shadloo m.s., M.S. Publication Date: 2019
Energy (0360-5442)179pp. 490-501
In this paper, a three-dimensional multiphase model of the polymer exchange membrane (PEM) fuel cell is simulated to study the effect of assembly pressure on the contact resistance between the gas diffusion layer (GDL) and bipolar plate (BP) interface. The results reveal that the increase of assembly pressure is associated with a decrease in the contact resistance between the GDL and BP interface, which results in reaching an ideal fuel cell performance. The performance improves until the assembly pressure of 4.5 MPa and it slightly drops with a clamping pressure of 5.5 MPa in the ohmic loss region of the polarization curve. Additionally, the variation of the electrical field in a cross-section of the channel length shows that the intrusion of GDL into the flow channel increases with increasing assembly pressure; consequently, the maximum electrical current will increase. The cell temperature rises at higher assembly pressure when considering the thermal contact resistance. This increase is higher on the cathode side because of the existence of the reaction heat source. Additionally, it is found that the distribution of electrical potential and oxygen concentration is more uniform at higher clamping pressure. This results in the development of the PEM fuel cell life cycle. © 2019 Elsevier Ltd
Moradi nafchi f., F.,
Afshari, E.,
Baniasadi, E.,
Javani, N. Publication Date: 2019
International Journal of Hydrogen Energy (03603199)44(34)pp. 18662-18670
In this paper, a mathematical model is developed to study the performance of a polymer membrane electrolyser (PEM) and the effect of different parameters including operating temperature, cathode pressure, membrane thickness, the width and height of channel and current density on the performance and energy and exergy efficiency of PEM electrolyser are investigated. In addition to the resistance overvoltage of components, the concentration overvoltage is modeled using an accurate equation. The model is validated against experimental data. The results indicate that by increasing current density, the voltage of the electrolyser increases, and energy and exergy efficiencies reduce. Increase of temperature from 313 K to 353 K, and decrease of cathode pressure from 40 bar to 1 bar lead to decrease of voltage of the PEM electrolyser by 8.3% and 4.8%, respectively. Moreover, energy and exergy efficiencies increase between 2% and 6% in the range of working temperature and pressure. It is concluded that decrease of membrane thickness, height and width of channel, and increase of exchange current density of the anode and cathode electrodes lead to decrease of voltage of the electrolyser and increase of energy and exergy efficiencies. However, the effect of temperature and cathode pressure and the exchange current densities is greater than the effect of geometric parameters. © 2018 Hydrogen Energy Publications LLC
Toghyani, S.,
Fakhradini, S.S.,
Afshari, E.,
Baniasadi, E.,
Abdollahzadeh jamalabadi, M.Y.,
Shadloo m.s., M.S. Publication Date: 2019
International Journal of Hydrogen Energy (03603199)44(13)pp. 6403-6414
In this research, the operating parameters of proton exchange membrane (PEM) electrolyzer are optimized in order to decrease the required input voltage using Taguchi method. The considered parameters include the operating temperature, the pressure of cathode and anode, membrane water content, membrane thickness, and cathode and anode exchange current density. First, a thermodynamic model is developed for the PEM electrolyzer, and then the Taguchi method is applied for optimization of the electrolyzer performance. The signal to noise ratio (SNR) and the analysis of variance (ANOVA) method are also performed to determine the contribution ratio of effective parameters. The results reveal that the optimal condition is achieved at maximum working temperature, membrane water content, and cathode and anode exchange current density and at minimum membrane thickness, cathode pressure, and anode pressure. The anode exchange current density has considerable effect on the electrolyzer voltage with contribution of 67.15% while the membrane water content and the anode pressure have a minor influence with contribution of 1.1% and 0.42%, respectively. © 2019 Hydrogen Energy Publications LLC
Publication Date: 2019
Journal of Thermal Analysis and Calorimetry (15882926)135(3)pp. 1823-1833
Flow field design has an important role in proton exchange membrane fuel cell (PEMFC) due to its effect on the distribution of pressure, current density, temperature, heat and water management and PEMFC performance. In this paper, the sinusoidal flow field is examined and compared with straight-parallel configuration using a finite volume method based on non-isothermal, steady-state and multiphase model. A set of continuity, momentum, energy, species and electrochemical equations is solved by CFD commercial code with SIMPLE algorithm as a solution approach. The obtained results reveal that at an operating voltage, the maximum velocity and pressure drop for sinusoidal flow field are 1.18 and 6 times more than straight-parallel flow field at GDL/CL interface. Also, it is found that the current density and maximum power density for sinusoidal flow field are 0.65 and 0.32 w cm−2, respectively. Ultimately, the results indicated that the sinusoidal flow field has better performance in compared with straight-parallel flow field. © 2018, Akadémiai Kiadó, Budapest, Hungary.
Publication Date: 2014
International Journal of Hydrogen Energy (03603199)39(27)pp. 14969-14979
A three-dimensional numerical model is developed to investigate and compare the performance of humidifiers with counter-flow and parallel-flow configurations. This model has a set of coupled equations including conservations of mass, momentum, species and energy. The results indicate that in counter-flow humidifier, water and heat transfer is more than that of the parallel-flow that leads to a higher dew point at dry side outlet, consequently, a better humidifier performance. An increase in temperature and a decrease in mass flow rate at dry side inlet lead to a better humidifier performance. However at the low flow rates the humidifier performance does not change a lot by preheating the inlet dry gas. An increase in relative humidity at dry side inlet does not offer any advantage. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Publication Date: 2012
Journal of Isfahan Medical School (10277595)30(199)pp. 1109-1118
Background: BK channels are highly conductive calcium (Ca2+)-activated potassium (K+) channels. These channels are available on the membrane of many types of neurons including cerebellar Purkinje cells. Several experimental studies have used iberiotoxin, a BK-specific channel blocker, to investigate the role of BK channels on electrophysiological behavior of Purkinje cells. Due to controversial results of mentioned research, we used computer simulation to assess the functional contribution of BK channels to the firing activity of Purkinje cells. Methods: Two realistic models of Purkinje cells with and without dendritic branches were used to investigate the functional contribution of BK channel to the firing activity of Purkinje cells. The simulations were performed in NEURON 7.1 simulator. Findings: The simulations using single compartment model (without dendritic branches) demonstrated that blocking BK channels slightly increased firing rate from 40 to 45 Hz. Simulation with the multi-compartmental model, which included the dendrites as well as the soma, showed that blocking BK channels abolished Ca2+spikes while sodium (Na+) spikes remained unchanged. Conclusion: The results obtained from simulations indicated that blocking BK channels has no significant effect on the tonic firing rate of Purkinje cells. Simulations also showed that dendritic BK channels have more effect on firing behavior of Purkinje cells compared with somatic BK channels. © 2012, Isfahan University of Medical Sciences(IUMS). All rights reserved.
Publication Date: 2009
IEEE Transactions on Signal Processing (19410476)57(8)pp. 3075-3085
Let A be an M by N(M > N) which is an instance of a real random Gaussian ensemble. In compressed sensing we are interested in finding the sparsest solution to the system of equations Ax = y for a given y. In general, whenever the sparsity of x is smaller than half the dimension of y then with overwhelming probability over A the sparsest solution is unique and can be found by an exhaustive search over x with an exponential time complexity for any y. The recent work of Candés, Donoho, and Tao shows that minimization of the ℓ1 norm of x subject to A x = y results in the sparsest solution provided the sparsity of x, say K, is smaller than a certain threshold for a given number of measurements. Specifically, if the dimension of y approaches the dimension of x, the sparsity of x should be K ≫ 0.239 N. Here, we consider the case where x is block sparse, i.e., x consists of n = N/d blocks where each block is of length d and is either a zero vector or a nonzero vector (under nonzero vector we consider a vector that can have both, zero and nonzero components). Instead of ℓ1-norm relaxation, we consider the following relaxation: min ∥ X1 ∥2 + ∥X2∥2 + ⋯ + ∥ Xn ∥2, subject to A x = y (*) where Xi = (x(i-1)d+1,x (i-1)d+2, ⋯ xid) T i = 1,2, ⋯ N. Our main result is that as n → ∞, (z.ast;) finds the sparsest solution to A x = y, with overwhelming probability in A, for any x whose sparsity is k/n < (1/2) - O(ε), provided m/n > 1 - 1/d, and d = Ω(log(1/ε)/ ε 3. The relaxation given in (z.ast;) can be solved in polynomial time using semi-definite programming. © 2009 IEEE.
Gordanshekan, A.,
Arabian, S.,
Tamimzadeh, A.,
Solaimany nazar a.r., A.R.,
Farhadian, M.,
Sabzyan, H.,
Tangestaninejad, S.,
Tavakoli, O. Publication Date: 2026
Applied Catalysis B: Environmental (0926-3373)385
Photocatalytic removal of Cefixime (CFX) by the synthesized green and reusable Bi2WO6/TiO2/GO ternary photocatalyst was investigated. XPS and Raman peak shifts, and HR-TEM and backscattered electron images were used to confirm the formation of the heterojunction. A photocatalytic reaction-informed neural network (PRINN) with [7 {11 8 4} 1] architecture was trained by a multi-objective genetic algorithm using boundary and initial conditions, governing laws, and an experimental dataset, included in 7 cost functions. Possible inter- and intra-particle electron transfer mechanisms involved in BTG 1 % were investigated. Density functional theory (DFT) computations justified experimental observations of the influence of the initial pH of the reaction mixture. DFT computations were conducted on the structure, bonding and energetics of the complex of the CFX molecule with hydroxyl and superoxide radicals in a cage of explicit water molecules to confirm the scavenger experiments. LC-MS experiments coupled with DFT computation and QSAR predictions were performed to propose a detailed reaction pathway and estimate their toxicities. © 2025 Elsevier B.V.
Publication Date: 2025
PLOS Water (27673219)4(12)
The ZnO/BiOBr/Bi2S3 dual Z-scheme heterojunction was synthesized via the solvothermal method, and the photocatalytic removal of cefixime (CFX) was investigated using the nanocomposite. Structural and morphological studies were conducted using XRD, FTIR, Raman spectroscopy, XRF, FE-SEM, TEM, UV-Vis DRS, PL, and BET. The results indicated that the ZnO/BiOBr/Bi2S3 exhibited a synergistic effect, reducing the band gap energy to 2.70eV and enhancing charge separation in comparison with individual and binary components. The Raman peak shifts confirmed the formation of heterojunction among the components. Optimization of the mass ratio through screening experiments resulted in an optimum composition of 30 wt% ZnO to BiOBr/Bi2S3, achieving a 75% removal efficiency. CFX adsorption on the nanocomposite followed a monolayer mechanism, with a maximum adsorption capacity of 15.32mg.g-1. In addition, approximately 96% CFX removal was achieved using the immobilized ternary ZnO/BiOBr/Bi2S3 heterojunction on graphite under optimal operating conditions. The O2–•and h+ for the suspended and the O2–•and OH• for the immobilized system play the major role in CFX degradation. © 2025 Rahpeyma et al.
Publication Date: 2025
Journal of Environmental Chemical Engineering (22133437)13(6)
In this study, we have developed a two-dimensional (2D), time-dependent mathematical model focusing on the desalination chamber (DC) of CPDCs. The model simulates ion transport mechanisms, including diffusion and migration, under laminar flow with recirculation between the DC and a well-mixed recirculation tank (RT). Governing equations for mass transfer were solved numerically in MATLAB, and the model was validated against lab-scale experimental data, demonstrating good agreement. The model enables detailed analysis of ion concentration profiles and salinity reduction within the DC, offering predictive insights into system optimization and scale-up. Key operational parameters, such as brackish water flow rate, cell height, intermembrane spacing, and electric potential difference (EPD), were systematically investigated through sensitivity analysis. The results highlight the nonlinear effects of design and operating conditions on desalination efficiency and help define optimal ranges for system configuration. Furthermore, by calculating ion-specific mass transfer coefficient, Sherwood–Reynolds (Sh–Re) correlations were derived for Na⁺ and Cl⁻. These correlations serve as engineering tools for scaling up CPDC modules and optimizing design without full-scale experimentation. In overall, this modeling framework serves as a foundation for future expansion to multi-chamber, fully coupled models that can capture bioelectrochemical dynamics and power generation, ultimately enabling integrated and scalable design of next-generation CPDC systems. © 2025 Elsevier Ltd.
Publication Date: 2025
Thermochimica Acta (00406031)754
Deep eutectic solvents (DESs) are gaining attention as sustainable alternatives to conventional solvents due to their tunable properties and environmental advantages. Yet, predicting their physical behavior, particularly acoustic properties like the speed of sound, remains limited, especially in approaches that consider chemical structure. This study introduces a hybrid machine learning framework that incorporates molecular-level information to predict the speed of sound in DES systems with high accuracy and interpretability. A dataset of 1001 experimental data points, collected from 92 distinct DESs under atmospheric pressure and varying temperatures, was used to train and evaluate the models. Instead of relying solely on bulk experimental parameters, the models integrate structural descriptors based on group and atomic contributions, capturing detailed chemical features of both hydrogen bond donors and acceptors. These structure-based inputs were embedded into machine learning algorithms to develop robust and generalizable predictive tools. The resulting models demonstrated excellent performance, achieving average absolute relative deviations below 1 %. In addition to strong predictive power, the framework allows for interpretation of how specific molecular characteristics influence acoustic behavior, offering a transparent view into the structure–property relationship. This work advances the application of machine learning in solvent science by uniting chemical intuition with data-driven modeling. The hybrid approach not only enhances predictive capability but also provides mechanistic insight, making it a valuable tool for the rational design and selection of DESs in green chemistry, materials processing, and related fields. © 2025 Elsevier B.V.
Given the common challenge of low solubility of many drugs in water, it is vital to implement novel methods to improve it. One method that is widely used across various applications is the use of co-solvents. In particular, Deep Eutectic Solvents have been recognized for their potential in the pharmaceutical industries. This potential is due to their environmental compatibility, cost-effectiveness, and desirable properties. Due to the large number and variety of deep eutectic solvents, it is not possible to perform experimental studies to determine the effect of Deep Eutectic Solvents on the solubility of drugs in water. Thus, it is vital to have thermodynamic models, to help researchers to estimate how the co-solvents enhance the solubility of drugs. This research investigates the performance of five relevant thermodynamic models. The investigated models are all empirical and require regression on the experimental data of each system to be used, which makes them non-predictive. Therefore, to overcome this issue, for the first time, the Khayam-Rajabi-Haghbakhsh model (KRH) has been developed as the first comprehensive and accurate predictive model for estimating the solubility of various drugs in water considering Deep Eutectic Solvents as co-solvents. For the development of this model, a comprehensive data bank including 1489 experimental data points for 13 different drugs and 17 Deep Eutectic Solvents has been used. The AARD% of this model has been calculated to be 13.00, indicating a high level of accuracy. Statistical analysis demonstrates acceptable and unbiased performance across all Deep Eutectic Solvents and drugs investigated. This model is widely utilized for various drug systems, water, and Deep Eutectic Solvents as co-solvents due to its comprehensiveness, accuracy, and capability to estimate drug solubility without needing experimental data. © 2025 Semnan University.
Publication Date: 2025
Chemical Engineering Journal (1385-8947)523
This study examines hydrogen gas production from biogas dry reforming in a Pd/YSZ membrane reactor (MR) packed with a Ni-based catalyst. The MR performance was investigated in terms of hydrogen permeation, methane and carbon dioxide conversion, hydrogen recovery, and hydrogen yield with a temperature range of 500–600 °C and pressures between 1 and 5 bar. At 600 °C, the Pd/YSZ membrane demonstrated a hydrogen permeance of 1.8 × 10−6 mol·m−2·s−1·Pa−1 and an apparent activation energy of 11.9 kJ/mol. Increasing the temperature from 500 °C to 550 °C at 5 bar resulted in CH4 and CO2 conversions increasing by 26 % and 6 %, respectively, while hydrogen recovery and yield improved by 6 % and 24 %. Our results showed higher CH4 conversion than other membrane reactors and conventional reactors under the same operating conditions. Experimental results indicate that methane decomposition occurs simultaneously with biogas reforming, contributing significantly to coke formation, particularly at elevated temperatures. Introducing small amounts of oxygen into the feed effectively reduced carbon deposition from 1.0 g to 0.65 g at 550 °C and 5 bar by oxidizing deposited carbon. However, this also led to a reduction in CO2 conversion from 22 % to 6 %, due to the consumption of CO2 during carbon oxidation reactions. Importantly, the addition of O2 did not negatively impact membrane and catalyst activity, and hydrogen recovery and yield remained stable. Additionally, steam regeneration was shown to effectively remove carbon deposits from both the catalyst and membrane, while simultaneously generating hydrogen via gas–solid reactions. So far, no research study has evaluated the effect of steam for coke removal on Pd-based membrane reactors. The MR exhibited stable hydrogen permeation flux and maintained complete selectivity over 800 h of continuous operation. Up to now, no Pd-based membrane has been resisted for this period under dry reforming reaction. Thus, Pd-YSZ MR demonstrates strong long-term operational stability and viability for low-carbon hydrogen production from renewable biogas. © 2025 Elsevier B.V.
Publication Date: 2026
Synthetic Metals (03796779)317
In this study, nanocomposites of conductive polymers (polyaniline and polypyrrole) with metal oxide nanoparticles (SnO₂ and ZnO) were synthesized and evaluated as ammonia sensors exposed to single-gas or binary-gas mixtures (ammonia with methanol, ethanol, or acetone) at room temperature. Sensor composites were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), and atomic force microscopy (AFM), that revealed the microstructural features influencing sensor performance. Taguchi experimental design was, first used to quantify the effects of polymer type, nanoparticle type, and nanoparticle loading on gas sensor response and selectivity when exposed to ammonia as single gas. The second experimental design was used to study the effect of these factors in presence of an interfere gas showing that the conductive polymer type dominated sensor behavior, while nanoparticles provided synergistic, polymer-dependent enhancements in charge transfer and active-site availability. Coexisting vapors affected ammonia detection, with acetone producing the least interference. The PAni/SnO₂ (20 wt%) composite was identified as optimal, delivering high ammonia response and selectivity. Long-term stability tests after 18 month, demonstrated a retention of over 86 % of the initial response, and cycling experiments confirmed repeatable operation. In addition, it we found that the moderate relative humidity (RH) enhances protonic conduction, while high RH partially reduces response due to polymer swelling. This work establishes a rationally engineered polymer–metal oxide nanocomposite platform for selective, durable ammonia sensing under realistic mixed-gas and humidity conditions. © 2025 Elsevier B.V.
