Water Concentration In Ethanol Research Articles

Investigating Cellulose Nanocrystal and Polyvinyl Alcohol Composite Film in Moisture Sensing Application

This study focused on utilizing cellulose nanocrystal (CNC)–polyvinyl alcohol (PVA) composite in optical sensor applications to detect high humidity conditions and determine water concentration in ethanol. We focused on the composite’s effectiveness in moisture absorption to demonstrate visual color change. We demonstrated that the different molecular weights of PVA significantly affect CNC’s chiral nematic structure and moisture absorption capability. PVA with molecular weight 88 k–97 k exhibited the disintegration of its chiral nematic structure at 30 wt%, whereas low molecular weight PVA (n~1750) showed no structural disintegration even at 100 wt% concentration when analyzed through UV-Vis spectroscopy. Further, the thermal crosslinking of the CNC-PVA composite showed no significant loss of moisture sensitivity for all molecular weights of the PVA. We observed that the addition of PVA to the sulfated CNC obtained from sulfuric acid hydrolysis did not facilitate moisture absorption significantly. A CNC-PVA sensor was developed which can detect high humidity with 2 h. of exposure time. 2,2,6,6-tetramethylpiperidin-1-piperidinyloxy oxidized CNC (TEMPO-CNC) having carboxylic functionality was also used to prepare the CNC-PVA composite films for comparing the effect of functional groups on moisture sensitivity. Finally, we demonstrated a facile method for utilizing the composite as an optical sensor to detect water concentration in ethanol efficiently; thus, it can be used in polar organic solvent dehydration applications.

Autoignition of ethanol-diesel blends: Is it worth dehydrating ethanol?

This study analyses the impact of the concentration of water in ethanol on the autoignition characteristics of ethanol-diesel blends. A constant volume combustion chamber was used to emulate the conditions of a diesel engine. Tests were carried out modifying the water content in the alcohol, and then the concentration of hydrated ethanol in the diesel fuel, at an initial temperature of 650 °C and 535 °C and pressure of 21 bar. The results reveal that, in general, the presence of water in alcohol, at concentrations requiring no additives to assure miscibility, has little effect on autoignition times. It was found that at low hydrated ethanol contents water acts as a reactivity inhibitor, probably associated with the endothermic effect of evaporation of the injection liquid. However, at higher concentrations of hydrated ethanol, water acts as an autoignition enhancer. Simulations suggest that the chemical effect associated with water as a third-body becomes more important compared to other effects. Finally, from an autoignition standpoint, exhaustive dehydration of ethanol is perhaps not necessary, which would open a market niche to hydrated ethanol derived from industry wastes or surplus.

Sensitive detection of DMSO/DMF in water, human urine and blood plasma using novel 1,8-naphthalimide-based amphiphilic spectroscopic probes

Dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) are industrial toxins that need to be sensed. We synthesized 1,8-naphthalimide-m-benzenesulfonamide (NBS)-bearing probes (1–5) with different pendant chains for sensitive detection of DMSO and DMF. These probes exhibited aggregation-induced emission enhancement with increasing water concentration in ethanol. Among these, monopod probes with a single NBS unit (1–4) selectively showed large fluorescence quenching upon addition of DMSO/DMF in water. Based on this result, we prepared two water-soluble probes (8 and 9) bearing the NBS unit. These probes displayed enhanced sensitivity in detecting DMSO/DMF in water compared to probe 1, showing an extraordinary low LOD of 0.0025% for DMSO and DMF detection in water. Probe 9 was similarly effective at sensitively sensing DMSO/DMF when tap or lake water was used as the medium, and the LOD of this probe was 0.05% when biological fluids such as diluted human urine and blood plasma were used instead of water. According to DLS, FE-SEM and zeta potential studies as well as DFT calculations, disaggregation of probe aggregates and electron transfer from the photo-excited probe to DMSO/DMF are likely both responsible for the high selectivity and sensitivity of this probe in detecting the organic solvents containing a sulfoxide/amide group.

OPTIMIZACIÓN DE LA DESHIDRATACIÓN Y EXTRACCIÓN DE COMPUESTOS FENÓLICOS DE PIEL DE MANGO

OPTIMIZATION OF DEHYDRATION AND EXTRACTION OF PHENOLIC COMPOUNDS FROM MANGO PEEL. Mango peel, a by-product obtained from the industrialization of this fruit, is a promising and inexpensive source of phenolic compounds. In the present study, both the drying of the mango peel and the extraction of phenolic compounds were optimized using the response surface methodology. In this sense, temperature and charge/area ratio were selected as depend variables to drying process. Instead, for the ultrasonic assisted extraction (UAE) the temperature, ethanol-water concentration and time were optimized. For both processes, the total phenolic content (TPC) and mangiferin concentrations were the response variables. The TPC and the xanthone concentration were determined by the Folin–Ciocalteu method and HPLC-ESI-IT-MSn , respectively. The optimal conditions for the dehydration process were 54 °C and 2.3 kg m-2, reaching a TPC of 21.7 ± 1.6 mg GAE g-1 dw and a concentration of mangiferin of 1.94 ± 0.22 mg g-1 dw. Regarding to UAE, the optimum conditions were 51 °C, 50% ethanol and 71 min. Under these conditions, the TPC was 19.5 ± 0.8 mg GAE g-1 dw and the mangiferin concentration corresponded to 1.50 ± 0.13 mg g-1 dw. Additionally, 38 compounds were identified in the extract obtained under optimal conditions.

Porous lead sulphide nanowalls structured film for ethanol detection in the short infrared regime

Porosity of semiconductor material has been used for various applications including gas sensing. However, the utilization of such materials for liquid sensing is still unexplored. Keeping this in mind, a highly porous structured film of lead sulphide (PbS) was engineered using a physical vapor deposition process. The fabricated PbS film was characterized for its shape and porosity using SEM, AFM, and Raman spectroscopy. Thus, the prepared PbS film was tested for various analytic aqueous media, such as ethanol, methanol, isopropanol, butanol, acetone, formaldehyde, and water for sensing. It was perceived that the prepared film was selectively responding to ethanol, while no such response was seen for the other analytic aqueous media and water. The prepared film showed a linear response for the detection of ethanol with the sensitivity of ∼0.002 transmission intensity (a.u.) per concentration of water (v/v%) at 1450 nm with a detection limit of 1.1%. Being operated in the short wavelength infrared range, this sensor can find applications in various fields, such as biofuel, medical, and organic chemistry. As compared to refractive index-based sensors which show nonmonotonic behavior with the concentration of water in ethanol, our sensor exhibits monotonic behavior over the whole range.

Experimental and Numerical Analysis of Laser-ignition of Wet Ethanol with Elevated Water Content

Higher production cost of anhydrous ethanol associated with distillation and dehydration process could be reduced through the direct use of wet/hydrous ethanol in engine applications. In this study, both experimental investigation and numerical analysis were carried out to quantify the effect of water content on laser ignition characteristics of premixed charge of wet ethanol with different water concentration and over a range of equivalence ratios. Combustion of wet ethanol was initiated through laser-induced breakdown from a Q-switched Nd:YAG laser. A high-speed camera is used to visualize the ignition event and flame propagation. Results demonstrated that, presence of water in ethanol up to 20% by volume accelerated the initial combustion reactions and led to faster burning. Adverse effects of elevated water concentration in ethanol at and beyond 30% (v/v), are more pronounced in fuel lean combustion region compared with fuel rich combustion. Laser-induced breakdown spectroscopic (LIBS) measurements revealed that, plasma temperature slightly increased with added water in ethanol up to 20% (v/v) as water in ethanol results in enhanced ionization of the gas mixture during laser breakdown, which leads to more intense absorption of laser energy. Therefore, this study demonstrates the potential of direct use of wet ethanol as an attractive fuel for IC engine.

Tribocorrosion and corrosion behavior of stainless steel coated with DLC films in ethanol with different concentrations of water

There has been a recent increase in both the production and consumption of ethanol due to the numerous environmental advantages that it offers, such as the fact that it can be produced from a variety of renewable materials, for instance corn and cellulose, or it can be obtained from sugarcane bagasse and biomass (2nd and 3rd generation ethanol). The result of this is that nowadays ethanol is widely seen as the dominant biofuel – or as a blend component in gasoline or pure fuel - in many countries.However, one disadvantage of the use of ethanol is the high corrosive behavior that occurs when its hygroscopic properties are exposed to a large number of materials. Xiaoyuan Lou and Preet Singh showed that the increase of water concentration in ethanol induces pitting and metal loss. Diamond-Like Carbon (DLC) films may be a solution to this problem due to the fact that they can be deposited inside tubes, offer good protection levels against corrosion, and reduce the friction coefficient and wear.This paper shows the tribocorrosion and corrosion studies of DLC films deposited on stainless steel grade 304 (SS304) substrates in order to gauge its appropriateness usage in the construction of pipelines and fuel storage tanks. The surface morphology was analyzed before and after 14 days of immersion. The tribocorrosion, friction coefficient, and wear rate were studied in ethanol to see the effects of water concentration. The films showed good adherence to the substrates. Corrosion and tribocorrosion results showed that for bare Stainless Steel 304 the increase of the water content increases the corrosion and the friction coefficient. DLC coated samples presented few points of delamination, and the friction coefficient and open circuit potentials were very low compared with the bare sample which was water concentration independent.

Optical-Ultrasonic Heterogeneous Sensor Based on Soft-Computing Models

A heterogeneous sensor system to determine the ethanol concentration in ethanol-water solution is demonstrated. The system consists of an optical-fiber refractometric transducer based on a long-period grating and a pair of ultrasonic transducers in transmission-reception mode, connected to a stand-alone electronic board for data acquisition, storage, and signal preprocessing. To implement a coherent sensor fusion from both measurement techniques, two soft computing methods (artificial neural network model and neuro-fuzzy model) are studied. A comparative analysis of these models was carried out based on the measured data. The best performance was obtained with the neural-network-based model. This model showed that it was able to correlate the responses of the optical-fiber transducer and the ultrasound system with the ethanol-water concentration. The final performance of the heterogeneous system is better within the whole range of concentrations, even if compared with the best performance of the individual sensors for limited ranges.

In-Line Measurement of Water Content in Ethanol Using a PVA-Coated Quartz Crystal Microbalance

An in-line device for measuring the water content in ethanol was developed using a polyvinyl alcohol (PVA)-coated quartz crystal microbalance. Bio-ethanol is widely used as the replacement of gasoline, and its water content is a key component of its specifications. When the PVA-coated quartz crystal microbalance is contacted with ethanol containing a small amount of water, the water is absorbed into the PVA increasing the load on the microbalance surface to cause a frequency drop. The determination performance of the PVA-coated microbalance is examined by measuring the frequency decreases in ethanol containing 2% to 10% water while the ethanol flows through the measurement device. The measurements indicates that the higher water content is the more the frequency reduction is, though some deviation in the measurements is observed. This indicates that the frequency measurement of an unknown concentration of water in ethanol can be used to determine the water content in ethanol. The PVA coating is examined by microscopy and FTIR (Fourier transform infrared) spectroscopy.

An Experimental Design Approach for Pressurized Liquid Extraction from Cardamom Seeds

Response surface methodology (RSM) was applied to evaluate the extraction conditions of Elettaria cardamomum Maton using pressurized liquid extraction (PLE). Influence of operating conditions such as temperature (90–150°C), ethanol-water concentration (25–75 wt%), and flow rate (1.0–4.0 mL/min) on the essential oil yield was investigated. The maximum yield from the response surface equation was predicted at 90°C, 75 wt% ethanol, and 4 mL/min. The essential oil composition of E. cardamomum using PLE followed by solid phase extraction was compared with hydrodistillation and Soxhlet extraction methods. The extraction yield for PLE was the highest one, and at the optimum conditions, the amount of desirable oxygenated components like 1,8-cineole and α-terpinenyl acetate were higher in PLE than in the hydrodistillation and Soxhlet method.

Quantification of water in ethanol using a photothermal transparent transducer

Ethanol with added water may be found during the process of assessing its physical and chemical properties. This addition can damage automotive vehicle engines and also may contribute to tax evasion. The present contribution describes a method based on a photothermal transparent transducer to determine the water content in ethanol. A chamber with a window of lithium tantalate coated with a thin layer of indium tin oxide was used, and a 1450-nm laser diode was employed as the excitation source. The results indicated a nearly linear response of the apparatus, as a function of the water content in water/ethanol solutions ranging from 0 to 100 (vol.%). The results for the dependency of the photothermal signal on the laser power and chopping frequency suggested that reliable results can be obtained using laser power and chopping rates above 100mW and 10Hz, respectively. The results reported here may be useful in the development of an alternative method that can provide real-time data on the water concentration in ethanol in a rapid, portable and unambiguous way, and that can be easily used in laboratory analyses or in gas stations.

High sensitivity LPG Mach–Zehnder sensor for real-time fuel conformity analysis

A high sensitivity refractive index sensor based on the combination of mechanically induced long period gratings (LPG) and fiber tapers was developed for real-time fuel quality analysis. The sensor was built in a Mach–Zehnder configuration by employing a pair of in-series gratings. In order to enhance sensor sensitivity, the region between both LPGs was tapered down from 125 to 10 µm. The system was tested by measuring water concentration in ethanol and ethanol concentration in commercial gasoline. The tapered sensor has shown an average sensitivity of 930 nm/RIU, 18 times higher than the non-tapered version. The resolution limit of the system using spectral interrogation was estimated to be 0.06% of ethanol dissolved in gasoline. For the purpose of real-time monitoring, an interrogation system based on white light interferometry (WLI) and virtual instrumentation was employed to evaluate ethanol evaporation in water, avoiding the use of spectral analysis. The WLI system, using phase tracking techniques, enabled us to record the evolution of the ethanol concentration in water with a resolution of 0.005% (v/v).

Ultrasonic Determination of Water Concentration in Ethanol Fuel Using Artificial Neural Networks

Detection of water concentration in ethanol is important for several industries because of ethanol's widespread use in a number of products, including alcoholic beverages, solvents, and transportation fuels. The miscibility of ethanol with water and other polar liquids makes ethanol susceptible to adulteration beyond the specifications. In this study, adulteration of ethanol was simulated by mixing anhydrous ethanol with water at known concentrations. Ultrasound speed and temperature measurements were used to estimate the water concentration in ethanol using two mathematical models. The first model was based on statistical curve fitting to the experimental data, and the second model was based on a feed-forward, back-propagation neural network algorithm. A total of 651 data sets containing ultrasound speed and temperature as inputs and water concentration in ethanol as output were used to train the neural network algorithm. Both models were validated by preparing ethanol and water mixtures at known concentrations. Validation experiments showed that water concentration in ethanol-water mixtures can be determined by using ultrasound speed and mixture temperature with a standard error of prediction of 8.6% with neural network model and 12.4% with an empirical model. Improving the accuracy and increasing the number of data points for neural network training would reduce the prediction error. The measurements of ultrasound speed and temperature do not involve any moving parts, and the method is rapid and non-invasive, which makes the ultrasound measurement system suitable for online monitoring of water concentration in ethanol.

Temperature Influence on Phase Stability of Ethanol-Gasoline Mixtures

The article investigates phase stability of ethanol-gasoline mixtures depending on their composition, water concentration in ethanol and ethanol-gasoline mixture and temperature. There have been determined the perfect functioning conditions of spark ignition engines fueled with ethanol-gasoline mixtures.

Determination of low-level water content in ethanol by fiber-optic evanescent absorption sensor

Evanescent field absorption spectroscopy in the infrared range of coiled fiber-optic sensor has been applied to determine the low-level water content in ethanol. Principal component regression and classical least square models have been utilized to build the calibration model and predict the water concentrations. The standard errors of predictions of water concentrations in ethanol were 3.16% and 0.42% respectively. Some methods to improve the accuracy of predicted water concentration in ethanol were suggested. The predicted concentration of water is acceptably accurate and cost-effective. The study demonstrates that the coiled fiber-optic sensor based on evanescent absorption spectroscopy is a feasible technology for prediction of the low-level water content in bio-ethanol and other industries in both on-line and remote situation.

Ethanol/water pulps from sugar cane straw and their biobleaching with xylanase from Bacillus pumilus

The influence of independent variables (temperature and time) on the cooking of sugar cane straw with ethanol/water mixtures was studied to determine operating conditions that obtain pulp with high cellulose contents and a low lignin content. An experimental 2(2) design was applied for temperatures of 185 and 215 degrees C, and time of 1 and 2.5 h with the ethanol/water mixture concentration and constant straw-to-solvent ratio. The system was scaled-up at 200 degrees C cooking temperature for 2 h with 50% ethanol-water concentration, and 1:10 (w/v) straw-to-solvent ratio to obtain a pulp with 3.14 cP viscosity, 58.09 kappa-number, and the chemical composition of the pulps were 3.2% pentosan and 31.5% lignin. Xylanase from Bacillus pumilus was then applied at a loading of 5-150 IU/g dry pulp in the sugar cane straw ethanol/water pulp at 50 degrees C for 2 and 20 h. To ethanol/water pulps, the best enzyme dosage was found to be 20 IU/g dry pulp at 20 h, and a high enzyme dosage of 150 IU/g dry pulp did not decrease the kappa-number of the pulp.

Twisted intra-molecular electron transfer phenomenon of dansyl immobilized on chitosan film and its sensing property to the composition of ethanol–water mixtures

A new fluorescent chitosan film bearing dansyl as a fluorophore has been prepared. The film shows dual fluorescence phenomenon due to twisted intra-molecular charge transfer (TICT) in the excited state of the fluorophore. The position of the maximum emission of the film depends on the polarity of the medium, and it shifts from 460 nm in ethanol to 505 nm in water. The two emissions have been attributed to the emission from the “locally excited” state or non-charge transfer excited state of dansyl and that from the TICT excited state of the fluorophore, respectively. Existence of TICT phenomenon of the immobilized dansyl has been confirmed and studied by various fluorescence techniques, such as fluorescence lifetime measurement, steady-state and time-resolved fluorescence emission spectroscopy measurements, etc. The ratio, I505/I460, of the intensities of the two emission bands depends linearly on the concentration of water in ethanol–water mixture provided the concentration is less than 40%. Furthermore, the sensing property of the film to the mixture is reversible.