Water Impurities Research Articles

Synthesis of Solketal Fuel Additive From Acetone and Glycerol Using CO2 as Switchable Catalyst

In this work, a design of experiments (DoE) was used to study the acetalization of glycerol with acetone using carbon dioxide as switchable catalyst. Experimental tests were carried out according to a fractional factorial design, with 2 levels and 4 factors (24-3), in combination with a response surface method (RSM), to study the significance of temperature, initial pressure of CO2, glycerol/acetone molar ratio and reaction time and then optimize the performance of the CO2 in this type of reaction. The response variable was the glycerol conversion that was analyzed by GC-MS. Temperature, reaction time and initial pressure of CO2 were statistically significant factors by Analysis of Variance (ANOVA). Molar ratio of glycerol/acetone was an insignificant factor in this reaction. An empirical model was derived, and experimentally validated, to predict the conversion of glycerol. The maximum conversions obtained by the model and experimentally were 60.36% and 60.60% at the optimal conditions defined as 118 oC, 42 bar and 5 h reaction time. It was done the ketalization with doped glycerin with several impurities (methanol, water and sodium chloride) to study its effects in this reaction. The addition of water and methanol decreases until 34% in glycerol conversion, while the addition of sodium chloride increases until 14% this variable. It was done reactions with glycerin from biodiesel production with NaOH and Ba(OH)2 and it was reached conversions of 6% and 20%, respectively.

Densities, Viscosities, and Electrical Conductivities of Pure Anhydrous Reline and Its Mixtures with Water in the Temperature Range (293.15 to 338.15) K

Density (rho), dynamic viscosity (eta), and electrical conductivity (kappa) of the deep eutectic solvent (DES) reline, composed of choline chloride (ChCl) and urea in a 1:2 molar ratio, and its mixtures with water, covering the entire miscibility range, were studied at T = (293.15 to 338.15) K. Compared to many previous studies, reline purity was significantly improved by using ultrapure urea and ChCl recrystallized from ethanol. For the investigated DES samples the mass fraction of residual water was <0.00035. This allowed checking the influence of water traces and impurities on the physicochemical properties of pure reline. It was found that the presence of small amounts of water (w(H2O) < 0.0081) only negligibly decreased reline density, not exceeding 0.14% compared to the dry sample. However, for the same amount of water decreased by similar to 36% at 298.15 K. The temperature dependence of rho was well fitted by a quadratic expression, whereas eta(T) and kappa(T) were found to follow the empirical Vogel-Fulcher-Tammann equation. For the aqueous mixtures excess properties of molar volume (V-E) and viscosity (eta(E)) showed only minor variation with composition, suggesting rather weak interactions between water and the constituents of reline. However, V-E and eta(E) depended significantly on temperature, indicating a significant contribution of H-bonding to the inherent reline structure. Similar to conventional ionic liquids, the conductivity of aqueous reline showed a broad maximum at the reline mole fraction of x(1) approximate to 0.18 associated with the border between aqueous solutions of individual reline components and reline/water mixtures. The Walden plot classifies reline as a poor ionic liquid.

The Influence of Electrolytes Composition on the Dissociation Rate of Natural Gas Hydrates Obtained in Model Stratum Waters

The study of the hydrates formation and decomposition kinetics in solutions of electrolytes is of interest due to the possibility of natural gas storing and transporting in a hydrate state, since the presence of impurities in water is inevitable under appropriate industrial processes. The kinetic parameters of decomposition reactions of natural gas hydrates obtained in model solutions simulating the composition and concentration of stratum waters of East Siberian fields are studied. These deposits are located within the Leno-Tunguskaya and Lena-Vilyuiskaya oil and gas provinces (OGP). The deposits of the Leno-Tunguskaya OGP are characterized by abnormally low reservoir temperatures and pressures (10° C and 16 MPa). The stratum waters belong to the chloride-calcium type, and by the type of the predominant cation either to the calcium or to the sodium subgroup of waters. The mineralization of stratum water can reach 400 g / l and higher. The abnormal high reservoir pressure is 36.3 MPa, the temperatures reach +66 °C for deposits of the Lena-Viluiskaya OGP. Mineralization of stratum water is from 40 to 180 g / l, there may be waters of chloride-calcium (subgroups of calcium and sodium) and sodium bicarbonate (subgroup of sodium) types. Therefore, hydrates of natural gas were obtained in model solutions of calcium and sodium chlorides, and also in solutions of sodium bicarbonate. The rate constants of hydrate decomposition reactions are determined by the Erofeev equation. The shape of the kinetic curves of hydrate decomposition depends on the type and degree of the model stratum water mineralization. The values of the constants n for the decomposition reactions of all hydrate samples are greater than one. This means that these reactions occur in the kinetic region, that is, the rate of hydrates decomposition is determined by the rate of physical desorption of the gas from the clathrate lattice. It has been established that the rate of hydrates decomposition increases with increasing mineralization, and it is higher in the presence of calcium chloride solutions than sodium chloride.

Analysis and Computational Methods for a Reader Solenoid Coil Used in Industrial Environments

This paper proposes a new reader solenoid coil with a metal tube for the use in high-temperature water, mud, and other impurities in an oil well downhole. The coil can read commands transmitted from the ground surface via inactive microtags and write the sensor data collected in the downhole into the microtags for transmission to the ground. By combining transformer theory and electromagnetic field theory, the main parameters of the reader solenoid coil in the harsh industrial environment in a downhole are calculated, and the main factors responsible for radio-frequency identification communication failure at 125 ± 10 kHz of the reader solenoid coil are analyzed. Then, a mathematical model is developed to describe the relationship among the electromagnetic field density, the ac resistance of complex permittivity, and the complex permeability with water and the metal tube of the reader solenoid coil. Methods to reduce the changes in the inductance and resistance are presented. The minimum flux density of the reader solenoid coil is designed to provide a continuous energy supply to inactive microtags, and the identification rate by the reader is 100% at 125 ± 10 kHz. Furthermore, the reader solenoid coil was tested in an industrial environment in the downholes of six oil well drilling systems for two years.

Solar still for saline water desalination for low-income coastal areas

Solar still is a simple device that utilizes the evaporation–condensation technique to convert impure saline water into the distilled water by eliminating dissolved salts as well as other dissolved impurities and suspended solids. This study aims to produce fresh drinking water from saline water with solar still in the context of Bangladesh. For this study, a pilot-scale solar still with an effective surface area of 0.214 m2 is fabricated with mild steel sheet. At first, solar still productivity is evaluated by varying basin water amount by 3 L, 3.5 L, 4 L and 4.5 L synthetic water. Experimental investigations show a decrease in water production with an increase in basin water amount. The optimum basin water amount is found to be 3.5 L at which distillate production is maximized. Then, the effect of salt concentration is assessed by synthetic solutions with 2000 ppm, 5000 ppm and 8000 ppm total dissolved solids (TDS). An inverse relation is found between salt concentration and freshwater production. Lastly, real seawater is fed to the basin and an average freshwater production of 2.38 L/m2-day is obtained with a removal efficiency of 99.87%, 99.83%, 99.78% and 99.81% for turbidity, chloride, TDS and electrical conductivity respectively.

The Reaction of Ethylenediamine with 1,4‐Bis(trimethylsilyl)butadiyne and the Role of Water: A Qualitative Method for the Determination of Water Impurities in Ethylenediamine

Alkenylation of [Ge9]4– and formation of the vinylated species [Ge9(CH=CH2)n](4–n)– proceed only in ethylenediamine (en) as a solvent. Variation of the alkyne leads to coupling products between the alkyne and en. Herein, we investigated the coupling reactions between 1,4‐bis(trimethylsilyl)butadiyne and en and showed that a water impurity in en plays a decisive role in the outcome of the reaction. NMR spectroscopic investigations revealed that 1‐trimethylsilyl‐7‐amino‐5‐aza‐hepta‐3‐en‐1‐yne is formed by addition of en at 1,4‐bis(trimethylsilyl)butadiyne. Addition of another amino‐functionality of en giving both the cyclization product and 1,9‐di‐amino‐4‐methyl‐3,7‐di‐aza‐nonadiene is only possible in presence of water. 1,9‐Di‐amino‐4‐methyl‐3,7‐di‐aza‐nonadiene is also formed by the reaction of deprotonated en with 1‐trimethylsilyl‐7‐amino‐5‐aza‐hepta‐3‐en‐1‐yne. Based on these results, we developed a simple method to detect water in en, supported by 1H NMR spectroscopy. The finding that 1,9‐di‐amino‐4‐methyl‐3,7‐di‐aza‐nonadiene is also formed by reaction of 1‐trimethylsilyl‐7‐amino‐5‐aza‐hepta‐3‐en‐1‐yne with deprotonated en was exploited to indirectly proof the deprotonation of en upon the nucleophilic reaction of [Ge9]4– with alkynes in the solvent en.

A surface acoustic wave device for water impurity levels monitoring by measuring signal-to-perturbation ratios

This paper reports a novel method for water impurity levels monitoring by measuring the signal-to-perturbation ratios (SPRs) of the surface acoustic wave (SAW) device. It has been shown that when a droplet is put on the SAW propagation surface, the SAW is attenuated and there will be a signal shift after the evaporation due to surface perturbations caused by impurity residues. For cleaner water, the SAW propagation surfaces are clean after the evaporation which cause smaller signal shifts or perturbations and then generate higher SPRs. However, for dirty water, the sensor SPRs are lower because of more impurity residues. Besides, the sensor detection performance has been compared with the total dissolved solids (TDS) meter. The results indicate that the average SPR of the SAW sensor presents a good linear response to the NaCl impurity content in lower concentration ranges of 100 to 1000 ppm similar to the TDS meter.

Plasmas sustained by repetitive nanosecond pulses: recombination mechanisms in Ar with trace amounts of H2O

A 0D kinetic model was developed to understand the electron-ion recombination in a plasma generated by high repetition frequency nanosecond pulses in argon with trace amounts (0.1% or less by volume) of water vapor at a total pressure of several Torr. The influence of trace amounts of water on the electron temperature and density decay was studied by solving electron energy and continuity equations. In pure argon, Ar+ ions dominate, the electron temperature is very slow to thermalize, and the recombination of electrons is also very slow. The presence of trace amounts of water impurity drastically reduces the electron thermalization time and increases the rate of recombination. The kinetic model provides a good fit to the previously acquired experimental data.

Effects of Temperature and Water Purity on Germination and Yield of Mungbean Sprouts

Mungbean (Vigna radiata L. Wilczek) is a popular pulse crop, producing protein-rich food and nitrogen-rich residues. Mungbean sprouts were grown at different temperature levels of 10, 20 and 30°C in various water purities of 30 (distilled water), 100, 400, 700 and 1000 TDS (ppm). After keeping them in the germination chamber for 72 h, the percentage of germination, stem length and yield along with proximate composition were determined. The temperature was kept as main factor and water purity as the second. The experiment was replicated four times and the data obtained were analyzed using two factorial completely randomized design. The results showed that both the factors had significant (p<0.05) effect on the germination, stem length, yield as well as proximate composition. A temperature of 30°C and water with high purity of 30 TDS resulted in high emergence (69%), stem length (3.14 cm) and yield (70.1 g) as compared to the other treatments. Minimum germination (2.1%), stem length (0.11 cm) and yield (12.11 g) were recorded in samples kept at low temperature of 10°C and water purity with 1000 TDS. The mungbean seeds showed a very low plasticity to water purity, and that they were very susceptible to water impurities. It is concluded that, to prepare sprouts from mungbeans, it is necessary to germinate mungbean seeds them in water having high purity and temperature of 30oC for maximum germination, stem length and yield.

Ultraviolet spectrophotometric sensor of hydrocarbon impurity in pure water

Ultraviolet spectrophotometric sensor of hydrocarbon impurity in pure water

Спектрофотометрическое определение активного хлора по окраске индофенольных соединений

Chlorination is a method of disinfection and oxidation of organic impurities in water. Chlorine is present in aqueous solutions in various forms, which are formed as a result of the chlorination of water. Spectrophotometric methods are very important for determining small amounts of chlorine and its compounds. The article presents a modification of the classical indophenolic method. Determination of active chlorine should be carried out at room temperature, maintaining the solutions for 50 minutes, the pH range is 11.9 ± 0.1. The optimal concentration of reagents: 33-fold excess of N-phenanthranilic acid, 2-fold excess of sodium nitroprusside, and the concentration of ammonium chloride should be 4 to 7 times less than the concentration of active chlorine. The following interaction scheme was proposed: oxidation of ammonia to chloramine with hypochlorite, amination of N-phenanthanilate with the formation of sodium 4-amino-N-phenylanthranilate, oxidation of 4-amino-N-phenylanthranilate with sodium hypochlorite to an indamin compound, followed by complexation with sodium nitroprusside. The linearity range of the calibration curve is 1-23 mg/l, the convergence is 2.3%, the relative error is 1%. The molar ratios of ions and oxidizing agents present in natural waters that do not interfere with the determination of active chlorine are investigated. The optimal concentrations of reagents, sequential variation of the concentration of solutions and fixing the change in light absorption were established. The ratio of the stoichiometric coefficients according to the reaction equation was: ammonium: N-phenanthranilic acid: sodium nitroprusside: hypochloride was 1: 2: 1: 1. It is proposed to use this method to determine the active chlorine in tap water. It is recommended to use the calibration schedule to determine the preliminary content, and to establish a more accurate concentration, use the method of additives.

Characterization and properties of polyethersulfone/ modified cellulose nanocrystals nanocomposite membranes

The aim of this study was to develop a novel nanocomposite membranes based on polyethersulfone (PES) and modified cellulose nanocrystals (CNCs) for removal of impurities from wastewater of licorice processing. The surface modification of CNCs was conducted by using (3-aminopropyl) triethoxysilane (APTES) to produce nanocomposite membrane with high efficiency. The chemical modification of CNCs was confirmed by Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and contact angle measurement. Later on, the mixed matrix nanocomposite membranes were prepared using polyethersulfone (PES) and various contents of modified CNCs (MCNC) (0.1, 0.5, and 1 wt%) as nanoparticles additives. The results showed that the nanocomposite membranes at 1 wt% MCNC concentration had the best efficiency of color removal (94%) and the chemical oxygen demand (COD) reduction (88%) from industrial waste water. The outcomes of this study demonstrated that the silylation of CNC can improve the efficacy of nanocomposite membranes to remove the water impurities, which may be suggested as simple technique for water filtration.

A Bifunctional Electrolyte Additive for High-Voltage LiNi0.5Mn1.5O4 Positive Electrodes.

4-(Trimethylsiloxy)-3-pentene-2-one (TMSPO) is tested as an electrolyte additive to enhance Coulombic efficiency and cycle retention for the Li/LiNi0.5Mn1.5O4 (LNMO) half-cell and graphite/LNMO full-cell. TMSPO carries two functional groups, siloxane (-Si-O-) and carbon-carbon (C═C) double bonds. It is found that the siloxane group reacts with hydrogen fluoride (HF), which is generated by hydrolysis of lithium hexafluorophosphate (LiPF6) by impure water in the electrolyte solution, to produce 4-hydroxypent-3-ene-2-one (HPO). The as-generated HPO, as well as TMSPO itself, is electrochemically oxidized to form a protective surface film on the LNMO electrode, in which it is inferred that the carbon-carbon (C═C) double bond initiates radical polymerization. The surface film derived from the TMSPO-added electrolyte shows a superior passivating ability to that generated from the pristine (TMSPO-free) electrolyte. The suppression of electrolyte oxidation enabled by the superior passivating ability offers two beneficial features to the half-cells and full-cells: the suppression of both HF generation and deposition of the resistive surface film on LNMO. As a result, the metal dissolution by HF attack on LNMO appears to be smaller by the addition of TMSPO. The cell polarization is also less significant because of the latter beneficial feature. In short, the bifunctional activity of TMSPO (HF scavenger and protective film former) allows an enhanced Coulombic efficiency and cycle retention to the half-cell and full-cell.

Improved sample treatment for the determination of flavonoids and polyphenols in sweet potato leaves by ultra performance convergence chromatography-tandem mass spectrometry

This work reports the development and application of a multi-compound analysis method for the determination of 17 flavonoids and polyphenols in sweet potato leaves. Samples were processed by microwave-enhanced accelerated solvent extraction under low pressure at 120 °C for 10 min. Salting-out homogeneous liquid-liquid extraction was used to remove water and water-soluble impurities from the extract before ultra performance convergence chromatography-tandem mass spectrometry analysis. By using the supercritical fluid (CO2 and methanol) as the mobile phase, the 17 components and the internal standard were well separated in 10 min without obvious matrix effect. Method validation was performed and good accuracy (relative error in the range of ±3.6%) and precision (inter- and intra-day relative standard deviations<10.9%) were obtained. The limits of detection were in the range of 0.1–0.6 ng ∙ mL−1. Recoveries were assessed at three concentration levels and acceptable mean values (76.1–101.5%) were found. This method has also been used to analyze ten different samples, and the average concentrations of components were determined in the range of 4.9–218.6 mg/100 g dry weight. The results showed the method could be helpful for the analysis of flavonoids and polyphenols in plant leaves.

Ester-Based Battery Solvents in Contact with Metallic Lithium: Effect of Water and Alcohol Impurities

Organic ester-based battery solvents were examined with respect to their reactivity with water and alcohols in contact with metallic lithium. The investigation was focused on monohydric esters (n-propyl acetate, isopropyl acetate), dihydric esters (trimethylene diacetate, 1,2-propylene glycol diacetate), and trihydric esters (triacetin). Experiments with lithium metal, the respective ester and water, and the matching alcohol were done. The resulting reaction solutions were analyzed with 1H NMR spectroscopy and compared to spectra recorded with the anticipated reaction products that were synthesized separately. The study reveals a tandem reaction from ester saponification to a catalytic Claisen condensation. Thus, the products formed during the reaction showed early degradation in cyclic voltammetry measurements in both the anodic and cathodic regions. A reactivity trend could be examined whereupon the trihydric esters were the least reactive followed by the dihydric and monohydric esters. In the absence o...

Determination of multi-class antibiotic residues in compost by microwave-enhanced accelerated solvent extraction and ultra performance convergence chromatography with tandem mass spectrometry.

This work reports the development and application of a multi-class compound analysis method for the determination of 20 antibiotic residues in compost. Samples were processed by microwave-enhanced accelerated solvent extraction at 120°C for 7.5min. Salting-out homogeneous liquid-liquid extraction was used to remove water and water-soluble impurities from the extract before ultra performance convergence chromatography with tandem mass spectrometry analysis. By using the supercritical fluid (carbon dioxide) and organic solvent (methanol) as the mobile phase, the 20 antibiotics and the internal standard were well separated in 8.2 min without obvious matrix effect. Method validation was performed and good trueness (relative error in the range of ±5.0%) and precision (inter- and intraday relative standard deviations<10.8%) were obtained. Method detection and quantitation limits were 0.8-1.9 and 2.7-7.1ng/g, respectively. Recoveries were assessed at three concentration levels (10, 60, and 400ng/g) and acceptable mean values (70.4-111.9%) were found. This method has also been used to analyze real samples, and the average concentrations of antibiotics (excepting the concentrations<method quantitation limits) were determined up to 123.6ng/g. The results showed the method could be helpful for the analysis of multi-class antibiotics in environmental samples.

Effects of Impure Water Sources on the Early-Age Properties of Calcium Sulfoaluminate (CSA) Cement

Abstract One of the benefits of calcium sulfoaluminate (CSA) cements is that these materials gain strength rapidly, and strength development is often measured in hours instead of days. This property makes these materials desirable for use in temporary, nonreinforced repairs of roadways, airfields, and navigable locks. The rapid repair of these infrastructure elements is critical to transporting supplies into regions devastated by disaster. In these austere environments, potable water may not be available in sufficient quantities to make vital repairs, and the use of impure water in the production of CSA cement–based concrete would be advantageous. However, the hydration products formed by CSA cement are significantly different from those formed by portland cement and may react differently to alkalis, chlorides, sulfates, and other contaminates that these impure water sources may contain. This article investigates the impact of calcium, sodium, potassium, and magnesium chloride and calcium, sodium, and magnesium sulfate on the early-age unconfined compressive strength development of commercially available CSA cement–based concrete. Of these salts, calcium chloride had the greatest effect on early-age concrete properties, retarding unconfined compressive strength development. The strength results obtained from CSA cement–based concrete mixed with these saline solutions are compared with those obtained from potential real-world sources of mixing water, including seawater and greywater.

Ambient noise analysis in underwater wireless communication using laser diode

The proposed system of a 450 nm blue GaN (Gallium Nitride) laser diode directly modulated by pre-leveled 16 Quadrature Amplitude Modulation(QAM) Orthogonal Frequency Divisional Multiplexing (OFDM)data is implemented to achieve high transmission capacity upto 10.02 Gbits/sec. The simulation analysis will be done under sea water and tap water to enable underwater wireless optical communication(UOWC) over a distance of upto 12 m. The UWOC tap water provide an allowable bit rate decrease from 16.57 to 14.67 Gbps with the transmission distance significantly increased from 2 m to 6 m, exhibit bit/distance decay ratio of −0.236 Gbps/m. By performing Underwater Optical Wireless Communication (UOWC) in sea water, the impurities in sea water scattered the light causing attenuation of the blue laser power. This reduces the transmission capacity with a slightly higher decay ratio −0.410 Gbps/m. There are other noise sources in the sea produced by creatures or by natural and man made activities. All these noise are also taken into consideration so that the ambient noise are eliminated with the help of digital signal processing.

Study of the Formation of a Solid Electrolyte Interphase (SEI) on a Silicon Nanowire Anode in Liquid Disiloxane Electrolyte with Nitrile End Groups for Lithium‐Ion Batteries

AbstractThe chemical compatibility of the various compounds and elements used in lithium‐based batteries dictates their safe operation parameters and performance. The lithium salt Li‐bis(trifluoromethanesulfonyl)imide (LiTFSI) has many advantages over the common LiPF6 salt as it does not react with water impurities to form, for example, hydrofluoric acid. To further accommodate safe‐operation chemistry, we use a non‐volatile disiloxane‐based solvent 1,3‐bis(cyanopropyl)tetramethyldisiloxane (TmdSx‐CN). This is a liquid disiloxane functionalized with terminal nitrile groups. In this paper, we report on the electrochemical characterization and the composition of the solid electrolyte interphase (SEI) of 1 mol kg−1 LiTFSI dissolved in TmdSx‐CN in silicon‐lithium batteries. Specifically, we study the SEI formation on silicon nanowire anodes and its composition by several ex‐situ surface techniques (XPS, SEM), and in‐situ via polarization modulation infrared reflectance absorption spectroscopy (PM‐IRRAS). We evaluate the potential application of TmdSx‐CN to silicon‐lithium batteries and conclude that the addition of fluoroethylene carbonate (FEC) at low concentrations (10 wt %) is essential to the formation of an effective SEI. We anticipate that our study will encourage the investigation, design and use of siloxane‐based solvents as safer alternatives to common solvents used in Li‐ion batteries, and specifically as candidate solvents in Li‐metal and silicon‐anode based batteries.

Effect of washing with diluted acids on Enteromorpha clathrata pyrolysis products: Towards enhanced bio-oil from seaweeds

Nowadays, macroalgae are widely discussed as advantageous alternative feedstock for crude bio-oil production using pyrolysis. In the present work, pyrolysis products of Enteromorpha clathrata washed with 7% phosphoric acid, hydrochloric acid and sulfuric acid were studied. In general, washing with diluted acids resulted in significant increase in the yields of bio-oil and non-condensable gas over the control in favor of the bio-char. In addition, HCl pretreatment enhanced the relative contents of aliphatic hydrocarbons in the bio-oil by 1.5 times over the control. Furthermore, HCl pretreatment showed 37% and 52.6% reduction in acids and oxygen-containing compounds, respectively, with respect to the control. FTIR analysis showed that acid-washing led to reduction in OH stretching vibration, confirming that it can disrupt hydroxyl bonds reducing phenols, carboxylic acids and water impurities in the bio-oil. In conclusion, washing of biomass using diluted acids could play a key role to enhance the bio-oil yield and significantly influence products characteristics; particularly, HCl enhanced bio-oil yield with higher aliphatic hydrocarbons proportion.