Increasing Ethanol Concentration Research Articles

Effect of Ethanol and Iso-Octane Blends on Isolated Low-Temperature Heat Release in a Spark Ignition Engine

<div>Low-temperature heat release (LTHR) is of interest for its potential to help control autoignition in advanced compression ignition (ACI) engines and mitigate knock in spark ignition (SI) engines. Previous studies have identified and investigated LTHR in both ACI and SI engines before the main high-temperature heat release (HTHR) event and, more recently, LTHR in isolation has been demonstrated in SI engines by appropriately curating the in-cylinder thermal state during compression and disabling the spark discharge. Ethanol is an increasingly common component of market fuel blends, owing to its renewable sources. In this work, the effect of adding ethanol to iso-octane (2,2,4-trimethylpentane) blends on their LTHR behavior is demonstrated. Tests were run on a motored single-cylinder engine elevated inlet air temperatures and pressures were adjusted to realize LTHR from blends of iso-octane and ethanol without entering the HTHR regime. The blends were tested with inlet temperatures of 40°C–140°C at equivalence ratios of 0.5, 0.67, and 1.0 with boosted (1.5 barA) conditions. The measured LTHR decreased with increasing ethanol content for all conditions tested; iso-octane–ethanol blends with above 20% ethanol content (by volume) showed minimal LTHR under engine conditions. These net effects resulted from the combination of thermal effects (charge cooling) and chemical effects (reactivity changes at low temperatures). The effect of temperature, pressure, fuel composition, and equivalence ratio on ignition delay times calculated from chemical kinetic modeling are presented alongside pressure–temperature trajectories of the in-cylinder gases to explain the trends. The underlying cause of the trends is explained by using a sensitivity analysis to determine the contribution of each reaction within the chemical kinetic mechanism to first-stage ignition, revealing the effect of introducing ethanol on the OH radical pool and resulting LTHR intensity.</div>

Experimental Study on Evaporation and Micro-Explosion Characteristics of Ethanol and Diesel Blended Droplets

In this study, the constant temperature control system of a heating plate was established, ethanol–diesel fuel with different proportions was prepared, and a series of experiments were carried out. The experimental system was used to observe, summarize, and analyze four evaporation and crushing modes of mixed droplets, which were explosion, liquid filament stretching, exocytosis, and ejection mode. The evaporation process of four kinds of mixed droplets in their life cycle was analyzed by normalizing the diameter square. It was proposed that the evaporation process of droplets could be divided into the following three stages: a heating stage, a fluctuating evaporation stage, and an equilibrium evaporation stage. It was also pointed out that the expansion, ejection, and micro-explosion of droplets were the causes of fluctuating evaporation. The concept of expansion and crushing intensity was put forward and the expansion and crushing intensity of ethanol/diesel mixed droplets with different proportions were calculated. The reasons why expansion and crushing intensity first increased and decreased with the increase in ethanol blending ratio were analyzed. Finally, the time proportion of ethanol–diesel mixed droplets in each evaporation stage was calculated, which explained that the time proportion of the instantaneous heating stage showed a parabolic law with the increase in ethanol content.

Heat Characteristics and Emission Effect of a Fuel-operated Auxiliary Air Heater Fed with Fuel E10, E30 and E100

In order to increase the comfort of vehicle passengers in specific vehicle categories, the heating of the passenger compartment is not provided by the heat from the engine driving the vehicle but by an additional heating device. The study examines the effect of auxiliary heaters that use liquid fuels to heat the passenger compartment of vehicles. The device was operated during the test with two different mixtures containing bioethanol (E30, E100) and the original motor gasoline (E10). It aimed to understand the effects of different fuels, particularly heating performance, operating time and emissions. Based on the results, as the ethanol content increases, the temperature of the device’s flame and heating air decreases. The experiments showed that in the case of E100 bioethanol, the average temperature measured in stable operating conditions was significantly lower than in the case of E10 motor gasoline. That suggests that an increase in the ethanol content reduces the heating performance. Another significant result of the study was that in the case of mixtures containing ethanol, a longer operating time is required to achieve the same amount of heat, which leads to additional fuel consumption. In addition, when using E100 bioethanol, the amount of harmful gases that are emitted increases significantly during the longer operating time. This observation can be important for evaluating the environmental impact and efficiency of vehicles.

Amine-free synthesis of high-silica ZSM-5 assisted with calcined silicalite-1 and ethanol with the investigation of mechanism

Amine-free synthesis of high silica ZSM-5 with high crystallinity and well-defined morphology was challenging. In this work, ZSM-5 with the fed silica-alumina ratio (SAR) of 100 was rapidly synthesized with the assistance of the calcined silicalite-1 seed and ethanol, and their crystal structures, morphology and microporous properties were characterized by XRD, SEM, FT-IR, ICP and N2 adsorption-desorption and so on. Firstly, the crystallization temperature was optimized between 140 and 180 °C at a certain alkalinity and ethanol content, and 160 °C was selected to not only provide high crystallization rate but also ensure the stability of high-silica skeleton. Secondly, the influences of the EtOH/SiO2 ratio, Na2O/SiO2 ratio and crystallization time on the crystallization of high-silica ZSM-5 were investigated at 160 °C. The results showed well-crystalline high-silica ZSM-5 could be synthesized within a wide range of the EtOH/SiO2 ratios (0.5–2.0) and the increase of ethanol content slightly inhibited the growth of ZSM-5 along b-axial of hexagonal prisms due to the preferential adsorption of excess ethanol on the {010} crystal plane and the formation of Si–O–C2H5; high alkalinity was favorable for the preparation of a small-sized and well-crystalline ZSM-5 due to the rapid depolymerization of calcined seed and the contribution of mass nucleation sites; meanwhile, excellent micropore characteristic of high-silica ZSM-5 further proved that the synthetic strategy of seed + ethanol was feasible. Finally, the synergistic action mechanism of calcined seed and ethanol for the synthesis of high-silica ZSM-5 was revealed that silicalite-1 with MFI structure unit combined with Na+(H2O/EtOH) with larger radius were very important for rapidly assembly of a large number of silica species into MFI framework.

Laminar and kinetic burning characteristics of ethanol/methane/hydrogen fuel: Experimental and numerical analysis

In this essay, the effects of ethanol addition on the fuels of Hydrogen methane mixing fuel were discussed. The laminar burning characteristics of ethanol/hydrogen/methane mixture under different ethanol content, pressure (1 bar, 2 bar), and equivalence ratios (0.7–1.4) were experimentally and numerically simulated. Results show that increasing ethanol content reduces the laminar burning velocity (LBV) and shifts the peak LBV towards higher equivalence ratios, attributed to the fuel mixture's decreased average combustion heat. For a 20 % ethanol content, the LBV peak appears at φ = 1.3, while for 50 % and 80 % ethanol content, it appears at φ = 1.2 locations. An empirical correlation for LBV as a function of ethanol concentration was developed, demonstrating predictions within a 4 % error margin compared to experimental data. High accuracy fittings of activation energy, ethanol concentration, and equivalence ratio were achieved, with correlation coefficients exceeding 0.9. Numerical simulations pinpointed key reactions and the relationship between free radicals and LBV, highlighting a pronounced correlation between OH radicals and LBV under lean conditions (coefficient of 1.0583), and a strong correlation with H radicals under rich conditions (coefficient of 1.01657), this indicates that OH and H are involved in the key chain reaction that promote the burning process.

Identification of Key Parameters Inducing Microbial Modulation during Backslopped Kombucha Fermentation.

The aim of this study was to assess the impact of production parameters on the reproducibility of kombucha fermentation over several production cycles based on backslopping. Six conditions with varying oxygen accessibility (specific interface surface) and initial acidity (through the inoculation rate) of the cultures were carried out and compared to an original kombucha consortium and a synthetic consortium assembled from yeasts and bacteria isolated from the original culture. Output parameters monitored were microbial populations, biofilm weight, key physico-chemical parameters and metabolites. Results highlighted the existence of phases in microbial dynamics as backslopping cycles progressed. The transitions between phases occurred faster for the synthetic consortium compared to the original kombucha. This led to microbial dynamics and fermentative kinetics that were reproducible over several cycles but that could also deviate and shift abruptly to different behaviors. These changes were mainly induced by an increase in the Saccharomyces cerevisiae population, associated with an intensification of sucrose hydrolysis, sugar consumption and an increase in ethanol content, without any significant acceleration in the rate of acidification. The study suggests that the reproducibility of kombucha fermentations relies on high biodiversity to slow down the modulations of microbial dynamics induced by the sustained rhythm of backslopping cycles.

Dynamics in the profile of biopolymers produced by mixed microbial cultures from ethanol-rich feedstocks

The use of agro-industrial wastes as substrates for polyhydroxyalkanoate (PHA) production by mixed microbial cultures is an alternative to lower the price of these biopolymers. However, when submitting these wastes to pre-fermentation, lactate and ethanol can be produced in addition to volatile fatty acids (VFAs). In this study, the impact of ethanol on PHA storage and in the carbon flux of the process were assessed. The co-production of extracellular polymeric substances (EPS) and its impact on PHA production was investigated. PHA production yield showed a decrease from 0.92 ± 0.004–0.63 ± 0.002 Cmol-PHA.Cmol-S−1 with the increase of ethanol content from 5 to 20 Cmmol.L−1. EPS production was directly proportional to the ethanol’s fed, reaching a maximum EPS total content of 6.70 Cmmol for the maximum ethanol supplied. EPS acted as a protection strategy, which benefited PHA specific storage rate for the highest ethanol content tested. These results indicate that ethanol-rich feedstocks can be valorised through the simultaneous production of two value-added biopolymers.

Effects of Ethanol Concentrations on Primary Structural and Bioactive Characteristics of Dendrobium officinale Polysaccharides.

Ethanol fractional precipitation can initially separate polysaccharides according to the structure, which exhibits strong correlation with the biological activities. This study aimed to investigate the impact of varying ethanol concentrations on the structural characteristics, and the antitumor and antioxidant activities of polysaccharides derived from Dendrobium officinale through ethanol fractional precipitation, as well as their internal relationships. The polysaccharides acquired by absolute alcohol additions at a final liquor-ethanol volume ratio of 1:1, 1:2, and 1:4 were named DOP-1, DOP-2, and DOP-4, and the supernatant was named DOP-S. The results of the structural analysis revealed that the increase in ethanol concentrations resulted in a reduction in the molecular weights and the acetylation degree of the polysaccharides, as well as a decrease in mannose content and an increase in glucose content. In vitro experiments demonstrated that DOP-S exhibited optimal antitumor and antioxidant activities. Animal experiments further confirmed that DOP-S suppressed the growth of solid tumors significantly, enhanced lymphocytes, mediated immune ability, and improved the activity of antioxidant enzymes. These findings would establish a theoretical foundation and provide technical support for further advances and applications of polysaccharides derived from D. officinale in the fields of food and medicine.

The promoting effect of electron beam irradiation on enzymatic saccharification and alcohol fermentation of sorghum meal: Related mechanisms

In this study, sorghum meal underwent 2–10 kGy electron beam irradiation (EBI) to investigate alterations in its elemental composition, relevant physicochemical characteristics, and enzymatic hydrolysis fermentation properties. The results indicated a decrease in amylose content and an increase in reducing sugar content in sorghum meal after EBI, along with severe damage to the internal structure of starch granules, leading to increased solubility in water. Furthermore, irradiation enhanced the shear resistance and gelatinization stability of sorghum meal paste. Most importantly, EBI-induced degradation of sorghum starch molecules enhanced their susceptibility to interact with α-amylase, significantly improving the enzymatic hydrolysis and alcohol fermentation efficiency of sorghum meal. At an irradiation dose of 8 kGy, raw and cooked sorghum meal exhibited a 43.40% and 33.33% increase in ethanol concentration and a 43.44% and 30.29% increase in ethanol yield, respectively. This finding indicated that irradiation is an effective pretreatment method for starch-based ethanol fermentation.

Effects of solvent on gelation behavior and gel properties of a dihydrazide derivative organogel

ABSTRACT By introducing more polar ethanol as a co-solvent to benzene, solvent effects on gelation behavior and gel properties of N,N’-bis (4-n-alkylo-xybenzoyl) hydrazine (4D16) were investigated herein. Xerogel of 4D16 showed fiber networks in benzene, while slice aggregates in benzene/ethanol mixtures and precipitates of 4D16 in ethanol showed rod-like aggregates. XRD patterns revealed that the aggregation structure of 4D16 translated from cubic phase to lamellar phase gradually with the increase of ethanol content. FT-IR spectra showed that the H-bonding of 4D16 showing lamellar phase was stronger than that in cubic phase. Kinetics of gelation 4D16 of showed that Df value of the aggregates increased firstly and decreased afterwards (1.204→1.522→1.244). Organogel in benzene/ethanol mixtures showed higher thermostability (Tgel ) and mechanic properties with the increase of ethanol content.

A study on the solubility of some amino acids in (H2O + EtOH) and (H2O + EtOH + NaI) systems by gravimetric method at T = 298.15 K: Experimental measurements and COSMO-RS calculations

In this study, the solubility of three amino acids including glycine, L-alanine, and L-valine was measured using the gravimetric method in aqueous mixtures with 0–100 % (w/w) ethanol in different salt concentrations of sodium iodide (from 0 to 2 mol kg−1) at 298.15 K and 89.1 kPa. The Setschenow equation was used to analyze the effect of the electrolyte on solubility. In addition, the multi-parameter Kamlet-Taft (KAT) equation was applied to provide detailed information on the solute–solvent and solvent–solvent interactions. Moreover, the molecular interactions in the solvent mixture were qualitatively investigated using the COSMO-RS method. The results showed that the solubility of each amino acid increases with increasing electrolyte concentration and decreases with increasing ethanol content in the solvent mixture. The Setschenow equation and experimental solubility data showed NaI's salting-in effect in the solubility process for all amino acids. It was found that the polarity-polarizability parameter of the solvent system has the most significant effect on the solubility of the amino acids. According to the COSMO-RS calculations, glycine and solvent system favor hydrogen bonding interactions while L-alanine and L-valine tend to interact with solvent more through hydrophobic interactions.

Evaluation of Arabica Coffee Fermentation Using Machine Learning

This study explores the variances in the organic, chemical, and sensory attributes of fermented coffee beans, specifically examining how post-harvest processes influence cup quality. Coffee fruits from the Catuaí IAC-144 variety were processed using both natural coffee (NC) and pulped coffee (PC) methods. The fruits were then subjected to self-induced anaerobic fermentation (SIAF) using one of the following fermentation methods: solid-state fermentation (SSF) or submerged fermentation (SMF). Within these methods, either spontaneous fermentation (SPF) or starter culture fermentation (SCF) was applied. Each method was conducted over periods of 24, 48, and 72 h. For this purpose, two-hundred-liter bioreactors were used, along with two control treatments. Numerous parameters were monitored throughout the fermentation process. A comprehensive chemical profiling and sensory analysis, adhering to the guidelines of the Specialty Coffee Association, were conducted to evaluate the influence of these fermentation processes on the flavor, aroma, and body characteristics of the coffee beverage across multiple dimensions. Data analysis and predictive modeling were performed using machine learning techniques. This study found that NC exhibited a higher production of acids (citric, malic, succinic, and lactic) compared to PC, resulting in distinct chemical and sensory profiles. The decision tree showed that fructose and malic and succinic acids were identified as the main factors enhancing sensory notes during cupping. SMF promoted higher concentrations of lactic acid, while SSF led to increased ethanol content. Consequently, the SIAF process enhances the sensory quality of coffee, adding value to the product by generating diverse sensory profiles.

Evaluation of the effect of increasing the organic load in the thermophilic co-fermentation of sugarcane industry by-products on hydrogen, ethanol and lactic acid generation

The effects of increased organic loading rate (OLR) on H2 production and soluble metabolites in a thermophilic anaerobic fluidized bed reactor (AFBR-AT) at 55 °C were evaluated by the fermentation of vinasse and molasses from sugarcane (at a ratio of 1:1). The OLR varied between 30 and 135 kg COD.m−3.d−1, while the hydraulic retention time (HRT) was fixed at 4 h, and the initial co-substrate concentration varied between 5 and 22.5 g COD.L−1. The thermophilic acidogenic reactor showed a maximum hydrogen yield (HY) (2.49 mmol H2.g−1CODapp) at an OLR of 30 kg COD.m−3.d−1 and a higher hydrogen production rate (HPR) (2.8 L H2.L−1.d−1) at an OLR of 45 kg COD.m−3.d−1. Increasing the OLR negatively influenced H2 production. The results showed an increase in ethanol (EtOH) concentrations of up to 47.3 times and lactic acid (HLa) concentrations of up to 15.2 times when comparing OLRs of 30 and 135 kg COD.m−3.d−1, indicating changes in metabolic pathways for acid formation at organic loads ≥90 kg COD.m−3.d−1. Thermoanaerobacterium was the bacteria with higher relative abundance and was directly involved in H2 production, while Lactobacillus was mainly involved in HLa production in higher OLR, decreasing H2 production instead. Besides that, higher OLRs were favorable for sulfidogenesis and the development of sulfate-reducing bacteria, such as Desulfobacterota, due to the higher COD/sulfate ratio in OLR 135 kg COD.m−3.d−1. According to the metabolic inference in this condition, the enzyme activity of sulfite reductase and sulfite dehydrogenase may have occurred, consuming H+, thereby reducing H2 production.

Understanding the effects of ethanol on the liposome bilayer structure using microfluidic-based time-resolved small-angle X-ray scattering and molecular dynamics simulations.

Lipid nanoparticles (LNPs) are essential carrier particles in drug delivery systems, particularly in ribonucleic acid delivery. In preparing lipid-based nanoparticles, microfluidic-based ethanol injection may produce precisely size-controlled nanoparticles. Ethanol is critical in LNP formation and post-treatment processes and affects liposome size, structure, lamellarity, and drug-loading efficiency. However, the effects of time-dependent changes in the ethanol concentration on the structural dynamics of liposomes are not clearly understood. Herein, we investigated ethanol-induced lipid bilayer changes in liposomes on a time scale from microseconds to tens of seconds using a microfluidic-based small-angle X-ray scattering (SAXS) measurement system coupled with molecular dynamics (MD) simulations. The time-resolved SAXS measurement system revealed that single unilamellar liposomes were converted to multilamellar liposomes within 0.8 s of contact with ethanol, and the d-spacing was decreased from 6.1 (w/o ethanol) to 4.4 nm (80% ethanol) with increasing ethanol concentration. We conducted 1 μs MD simulations to understand the molecular-level structural changes in the liposomes. The MD simulations revealed that the changes in the lamellar structure caused by ethanol at the molecular level could explain the structural changes in the liposomes observed via time-resolved SAXS. Therefore, the post-treatment process to remove residual ethanol is critical in liposome formation.

STABILITY OF COBALT AND NICKEL COMPLEXES OF SUCCINIC AND MALEIC IONS STUDIED BY POTENTIOMETRIC TITRATION, UV-VIS SPECTROPHOTOMETRY AND QUANTUM CHEMICAL CALCULATIONS

In this study, composition and stability of coordination compounds of nickel (II) and cobalt (II) ions with succinate anion (L2-) and maleic anion (Y2-) in aqueous ethanol solutions with the molar concentration of ethanol ranging from 0.0 – 0.3 were studied by UV – Vis spectrophotometry at ionic strength of 0.1 maintained with sodium perchlorate. The result showed that, the formation of mono-ligand complexes of Ni2+ and Co2+ ions with succinate and maleic anions become stronger when the volume of ethanol rises. This may be due mainly to a change in the solvate state of the ligand with increasing ethanol concentration in the solvent. In all surveyed solvents, Co2+ forms less stable complexes than Ni2+ ion corresponding to the Irving-Williams series established for aqueous solutions. Obtained results were compared with literature data for akin compounds. The effect of solvent composition change on the geometry, charge, total electron and free Gibbs energies was studied using the DFT and MP2 levels of theory by using the Polarizable Continuum Model (PCM). The results obtained in this article by UV – Vis spectrophotometry and theoretical calculations were analyzed together with the potentiometric titration results obtained by us earlier for these complexes. The results of theoretical calculations are in good agreement with experimental data.

Isolation and identification of yeasts from local fruits in Thua Thien Hue province, Vietnam

In this study, a total of 30 yeast isolates were recovered from local fruits in Thua Thien Hue province. Genetic characterization based on the ITS sequences identified isolates belonging to 3 species including Saccharomyces cerevisiae, Lachancea fermentati, and Clavispora fructus, with high sequence homology (over 99%) compared to published sequences in the GenBank. All identified S. cerevisiae isolates could grow well at 30°C and ferment several sugar including fructose, galactose, sucrose, mannose, maltose, and raffinose with different performances, but were inhibited at temperature higher than 35°C. The strains also grew well in the medium containing 5% ethanol (v/v) and 200 g/L glucose, but their growth ability was decreased gradually with an increase in ethanol and glucose concentrations. Interestingly, D14 strain was able to grow in the medium supplemented with 12% of ethanol, and 500 g/L of glucose at 45°C, while D7 strain could utilize both mannitol and glycerol at a low level. Our results also indicated that some strains have relatively high sedimentation efficiency, which are favorable conditions for beer fermentation and biomass recovery. The isolated yeast strains with good tolerance properties may provide a potential source of valuable raw materials for applications in beverage production and food processing.

Synthesis of Poly[N‐(2‐((3‐Morpholino‐3‐Oxopropyl)Thio)Ethyl)Methacrylamide]: A New Thermoresponsive Polymer with Tunable LCST‐ and UCST‐Type Phase Transition in Aqueous and Alcoholic Solutions

AbstractA novel monomer, N‐(2‐((3‐morpholine‐3‐isopropyl)thio)ethyl)methacrylamide (MTMA), is synthesized and polymerized by reversible addition‐fragmentation chain transfer (RAFT) polymerization to give a thermoresponsive polymer poly[N‐(2‐((3‐morpholino‐3‐oxopropyl)thio)ethyl)methacrylamide] (PMTMA). PMTMA exhibits reversible thermoresponsive phase transitions of the lower critical solution temperature (LCST) type in water and the upper critical solution temperature (UCST) type in ethanol and methanol. The degree of polymerization and concentration of PMTMA, and solvent type have a significant influence on the transition temperature. PMTMA shows complicated thermoresponse in water–alcohol mixtures. In water–ethanol mixtures, the phase diagram of PMTMA can be divided into three regions according to ethanol volume percentages, φ: 0 ≤ φ < 15% for an LCST region; 15% ≤ φ < 91.5% for a complete dissolution region; 91.5% ≤ φ ≤ 100% for a UCST region. At high water content, the LCST increases with increasing ethanol content; and at high ethanol content, the UCST decreases with increasing water content. In water–methanol mixtures, PMTMA shows more complex thermoresponse. In the range of 0–50 °C, the phase diagram can be divided into five regions, depending on the methanol volume percentages φ: 0 ≤ φ < 15% for LCST region; 15% ≤ φ < 25% for immiscible region; 25% ≤ φ < 85% for UCST region; 85% ≤ φ < 95% for fully dissolved region; 95% ≤ φ ≤ 100% for another UCST region.

Startup operation of an energetically-intensified single-tube type falling film distillation column: Insights from a pilot-scale study

Technological advancements in the field of energetically intensified falling film distillation columns have not been paralleled by sufficient published research on comparative startup evaluations for the single-tube falling film distillation column under different thermal energy transfer methods. The present study's originality and significance stem from presenting a startup procedure for a single-tube type falling film distillation column that employs a biphasic thermosyphon as a heat source for producing hydrated ethanol at a pilot scale. The concept of three discrete phases, the discontinuous, semi-continuous, and continuous phases, was employed to characterize the startup operation. The time and energy required for each phase of the startup operation were determined. This study also examined the startup operation with respect to two possible thermal energy transfer methods from the steam chamber to the distillation tube: isothermal and non-isothermal. The experiments were conducted in a pilot distillation column consisting of a single vertical tube, which processed a binary mixture of water and ethanol with a flow rate of 33 kg h−1. No relevant variation in startup time was detected for the three distinct stages when comparing the two heating modes, with a total startup duration of 2.2 h being observed irrespective of the heating configuration utilized. The isothermal heating configuration can produce hydrated ethanol at a rate of 3.0 kg h−1, with an ethanol content increase from 12.5 to 62.8 wt%. However, the non-isothermal heating mode yields a higher ethanol content an increase in ethanol content from 12.5 to 64.3 wt.%, albeit with a lower productivity rate of 1.3 kg h−1. Operating the single-tube type falling film distillation column with the steam chamber under the non-isothermal heating mode required only 2.12 kW for the startup, resulting in a 30.30 % reduction in energy demand compared to the isothermal heating configuration. The presented findings provide an empirical foundation for improving the efficiency and effectiveness of energetically intensified falling film distillation columns.

Synthesis of Pd-Cu/TPPCu electrocatalyst for direct ethanol fuel cell applications

In this study, the electro-oxidation reaction of ethanol over Pd–Cu supported on Cu porphyrin (TPPCu) was investigated. The catalyst was synthesized using the microwave-assisted polyol method and physicochemically characterized by XRD, XPS, SEM, EDS, TEM, EDAX, UV–Vis, FTIR, and RBS. A Cu-enriched catalyst with Cu3Pd, Pd,Cu, and TPPCu phases was identified using XRD and XPS. However, according to the RBS results, the catalytic surface was enriched with Pd, indicating that the interaction between TPPCu and Pd–Cu allowed the presence of Pd on the surface, thus enhancing the catalytic response of the material. This synthesis prevented the deprotonation of porphyrin on the electrocatalyst, as confirmed by XPS analysis. Electrochemical studies based on cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the response of the catalyst to variations in the scan rate and increasing ethanol concentration. The electrochemical response of PdCu/TPPCu improved with an increasing number of cycles, indicating improved mass transport, thus improving its electrochemical response and tolerance to CO contamination. This catalyst exhibited a high electroactive surface area of 49.4 m2/g, which could be related to the presence of TPPCu as a support. The behavior of the catalyst on the anode of a fuel cell fed with ethanol, bioethanol, and bioethanol residues was evaluated.Graphical

Effect of inoculum size and agitation speed on bioethanol production by Kluyveromyces marxianus using sugarcane molasse

In this study, bioethanol production was carried out at a high temperature (40 0C) using Kluyveromyces marxianus in sugar cane molasses media with a study of combinations in fermentation conditions in the form of inoculum concentration and agitation speed. This study investigated the effect of inoculum concentration and agitation speed on bioethanol production. This study used a factorial randomized block design with two factors: inoculum concentration (with levels of 5%, 10%, and 15% (v/v)) and agitation speed (with levels of 100, 150, and 200 rpm). The results showed that the interaction of inoculum concentration and agitation speed significantly decreased pH, total sugar consumption, total reducing sugar (TRS) consumption, and total dissolved solids (TDS). However, an increase in cell optical density (OD), ethanol concentration, and ethanol yields was evident from all treatments. The best treatment was from a combination of 10% inoculum with an agitation speed of 150 rpm, giving the highest ethanol concentration of 3.44% and ethanol yields of 89.91%.