Aqueous Solutions Of Blends Research Articles

Flexible Humidity Sensor Based on a Graphene Oxide-Carbon Nanotube-Modified Co3O4 Nanoparticle-Embedded Laser-Induced Graphene Electrode.

To meet evolving humidity monitoring needs, the development of flexible, high-performance humidity sensors is crucial. This study introduces an innovative flexible humidity sensor using a single-step laser scribing technique to fabricate a flexible in situ Co3O4 nanoparticle-embedded laser-induced graphene (Co3O4-LIG) composite electrode. Compared to conventional LIG electrodes, the Co3O4-LIG electrode exhibits improved conductivity and hydrophilicity, enhancing charge transfer and water molecule affinity. The unique two-dimensional structure and exceptional water permeability of graphene oxide (GO) combine with the rapid water response and high specific surface area of carboxylated multiwalled carbon nanotubes (MWCNTs), thereby assuming a crucial function in the modification and optimization of the performance of humidity sensors. Through the application of a homogenously blended aqueous solution comprising GO and MWCNTs in precise proportions onto the Co3O4-LIG composite electrode, an excellent humidity-responsive layer is established, culminating in the realization of a cutting-edge GO-MWCNTs@Co3O4-LIG flexible humidity sensor. Noteworthy attributes of this sensor include a heightened sensitivity [959.1% (ΔR/R0)], rapid response and recovery times (within 5 and 26 s, respectively), and a noteworthy linearity (R2 = 0.994) across a relative humidity range of 14 to 95%. The findings presented herein offer valuable insights and a practical blueprint for the design and production of flexible humidity sensors.

Carbon dioxide capture in a HiGee reactor with packing featuring controllable cross-sectional area

A rotating packed bed (RPB), as one of the typical HiGee reactors, has achieved extensive praise in CO2 capture fields. In this work, the novel mesh packings with controllable cross-sectional areas (CSAs) were applied to intensify the CO2 absorption process in an RPB, as well as combining with the blended aqueous amine solutions including diethylenetriamine (DETA) and piperazine (PZ). The gas pressure drop and CO2 absorption performance of various packings were investigated. Different operating conditions including rotational speed (400–2400 r/min), liquid flow rate (10–35 L/h), gas flow rate (900–2400 L/h), and CO2 molar fraction in gas inlet (2–12%) were considered. The results exhibited that the rise in gas pressure drop of concentric packing with constant CSA (CONC-9) relative to conventional coiled packing with increasing CSA (COII-9) was less than 10% on average. Meanwhile, the CO2 absorption efficiency of CONC-9 exceeded 17.1% on average than that of COII-9. For further comparison, the ratio of mass transfer coefficient to gas pressure drop in the wet RPB (KGa/△PW) was analyzed. The KGa/△PW of CONC-9 was 48.6% larger on average than that of COII-9. The average mass transfer coefficient and height of mass transfer unit of CONC-9 reached up to 16.7 kmol∙kPa−1∙m−3∙h−1 and 0.013 m, respectively. Overall, it is a viable way to adopt the packing with constant CSA to intensify the CO2 absorption in RPBs.

Synthesis and Characterization of a Conductive Polymer Blend Based on PEDOT:PSS and Its Electromagnetic Applications.

The purpose of this study is to prepare a resistive lossy material using conducting polymers for electromagnetic wave absorbers. This paper presents a conductive paste largely composed of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) with a polyurethane binder. The various secondary compounds are added in small amounts to an aqueous blended solution in order to enhance the electrical and mechanical properties of the conductive thin film. The synthesized conductive paste is characterized through electrical, chemical, and morphological analyses. The electrical conductivity of the thin film is measured using a four-point probe and surface profiler. The chemical and morphological changes are studied in various experiments using a Raman microscope, X-ray photoelectron spectroscopy, a scanning electron microscope, and an atomic force microscope. In order to verify the applicability of the synthesized conductive paste, which is composed of 70 wt% PEDOT:PSS, 30 wt% polyurethane, and secondary additives (DMAE 0.4 wt%, A-187 0.5 wt%, DMSO 7 wt%, Dynol 604 0.1 wt%, PUR 40 2.5 wt%), the Salisbury screen absorber is fabricated and evaluated in the X-band. According to the results, the absorber resonates at 9.7 GHz, the reflection loss is −38.6 dB, and the 90% absorption bandwidth is 3.4 GHz (8.2 to 11.6 GHz). Through this experiment, the applicability of the PEDOT:PSS-based conductive paste is sufficiently verified and it is found that excellent radar-absorbing performance can be realized.

Optimization and modeling of carbon dioxide absorption into blended sulfolane and piperazine aqueous solution in a stirrer reactor

Optimization and modeling of carbon dioxide absorption into blended sulfolane and piperazine aqueous solution in a stirrer reactor

Carbon dioxide absorption with aqueous amine solutions promoted by piperazine and 1-methylpiperazine in a rotating zigzag bed

In order to overcome the drawback of short liquid resistance time in rotating packed bed (RPB), a multi-stage rotating zigzag bed (RZB) was employed to enhance carbon dioxide (CO2) absorption process with blended aqueous amine solutions containing diethylenetriamine (DETA) + piperazine (PZ) or DETA + 1-methylpiperazine (1-MPZ) as absorbents. The effects of different operating parameters on the CO2 absorption efficiency, overall gas-phase volumetric mass transfer coefficient (KGa) and height of mass transfer unit in the RZB were investigated. Experimental results indicated that increase of the promoter concentration, lean solution flow rate and rotational speed were conducive to gas–liquid mass transfer and CO2 absorption. It was found that both PZ and 1-MPZ were effective promoters, while PZ exhibited better performance. Meanwhile, comparison of CO2 absorption performance between one stage and two stages revealed that two stages had higher CO2 absorption efficiency due to extended residence time of absorbents and CO2 in the RZB. A comparison with RPB demonstrated that the RZB could achieve higher mass transfer and CO2 absorption efficiencies with smaller rotor volume and less absorbent consumption. The maximum CO2 absorption efficiency and KGa reached 99.3% at a gas flow rate of 1.5 m3/h and 7.43 kmol/kPa m3 h at an inlet gas CO2 concentration of 2% respectively in the RZB with DETA + PZ system, suggesting that RZB may be an effective device for CO2 absorption.

Amine blending optimization for maximizing CO2 absorption capacity in a diisopropanolamine – methyldiethanolamine – H2O system using the electrolyte UNIQUAC model

Experimental data on CO2 solubility in diisopropanolamine (DIPA) and methyldiethanolamine (MDEA) blended aqueous solutions were measured at different amine blending ratios and working temperatures. The successive (iterative) substitution method was implemented to calculate the molar fractions of all chemical species, including molecules and electrolytes, from equilibrium along with four material balances and one electroneutrality equation. The electrolyte universal quasi-chemical (electrolyte UNIQUAC) model was used to consider the nonideality in the liquid phase. The partial pressures of CO2 in the gas phase and molar fractions of all components in the liquid phase were recalculated using thermodynamic models. In addition, the effect of the blending ratio of DIPA, MDEA, and H2O was investigated and expressed using the newly applied triangular diagrams of pH, heat of absorption, and cyclic capacity of CO2 according to the absorption and stripping conditions.

Effect of Blending Ratio and Temperature on CO2 Solubility in Blended Aqueous Solution of Monoethanolamine and 2-Amino-2-methyl-propanol: Experimental and Modeling Study Using the Electrolyte Nonrandom Two-Liquid Model.

This paper reports the newly measured experimental data for CO2 solubility in a blended aqueous solution of monoethanolamine (MEA) and 2-amino-2-methyl-propanol (AMP) at different amine mixing ratios (MEA/AMP/H2O = 9:21:70, 15:15:70, and 21:9:70 wt %) and working temperatures (323.15, 373.15, and 383.15 K). The successive substitution method was used for calculating the mole fractions of all molecules (four molecules) and electrolytes (three cations and four anions) from the equilibrium along with the material and charge balance equations (11 equations). The electrolyte nonrandom two-liquid (e-NRTL) model was used to investigate nonideality in the liquid phase. Using the abovementioned thermodynamic models, the partial pressures of CO2 in the gas phase, mole fractions of all components in the liquid phase, pH variations, heats of absorption, and cyclic capacities of CO2 according to the absorption/desorption temperature and the blending ratio of MEA/AMP were estimated.

An experimental and modeling approach to investigate CO2 solubility in blended aqueous solutions of 2-amino-2-hydroxymethyl-1, 3-propanediol (AHPD) and piperazine (PZ)

In this work, CO 2 solubility was investigated in a blended aqueous solution of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) and piperazine (PZ). Concentration of AHPD was varied from ( w ​= ​0.13, 0.19, and 0.25), while concentration of PZ was varied from ( w ​= ​0, 0.0174, 0.0688, and 0.1035). All experiments were performed at temperatures of 303.15, 313.15, and 333.15 ​K and over a CO 2 pressure range of (5–60) bar. CO 2 solubility was calculated in terms of CO 2 loading (mole of CO 2 /mole of amine absorbed). Effect of temperature, equilibrium CO 2 pressure, and PZ concentration on CO 2 loading was examined. Artificial neural network (ANN) model was developed to correlate CO 2 solubility data. It was found that correlated CO 2 solubility data from ANN model were in good agreement with experimental CO 2 solubility data. • Solubility of CO 2 in PZ Activated aqueous solution of AHPD was measured. • Effect of Temperature, Pressure and Concentration on CO 2 solubility was studied. • Solubility was measured up to the pressure of 60 ​bar. • ANN model was developed to correlate the measured data.

Rheological behavior of regenerated silk fibroin/polyvinyl alcohol blended solutions in steady and dynamic state and the effect of temperature

Since the silk fibroin is a precious material widely used in various fields, the discarded silk textile is a profound waste in resource-constrained settings. In this paper, with recyclability in mind, we selected waste silk from discarded silk quilt to make the regenerated silk fibroin (RSF) aqueous solutions. Mixing with water-soluble polyvinyl alcohol (PVA), the RSF/PVA blended solutions were made as a spinning dope for preparing the regenerated fibers. To optimize the parameters during the spinning process, we used the rheological measurement firstly to investigate the fundamental characters of solutions with various blending ratios and the effect of temperature on solutions. The results showed the RSF/PVA blended aqueous solutions were non-Newtonian fluids, and the apparent viscosity rose with the increasing PVA contents in co-solutions and decreased with the growth of the shear rate. The blending ratio had a certain influence on the viscoelasticity of co-solutions, the more the percentage of PVA, the higher the value of the viscoelasticity of co-solutions would be, and the co-solution with blending ratio of 6:4 (RSF:PVA) showed the greatest influence on storage modulus, while the solutions with more RSF exhibited more effect on loss modulus. Too much PVA content or too high RSF proportion in solutions was unfavorable to spinning. What’s more, the co-solutions with RSF content less than 40% had the most similar morphological structural systems, and the co-solutions containing more than 20% PVA had narrow distribution, linear and high molecular weight. For preventing protein denaturation, the temperature should not be higher than around 30 °C.

Investigation of overall mass transfer coefficient of CO2 absorption in to aqueous blended Monoethanolamine (MEA), Diethanolamine (DEA) and Triethanolamine (TEA) measured in Bubble column Reactor solution

Mixtures of different types of amine solution (primary Monoethanolamine (MEA), secondary : diethanolamine (DEA) and tertiary: triethanolamine (TEA) were experimentally used to investigation the overall mass transfer coefficient (KGa ) at different operating parameters. The experiments were made in a bubble column reactor (BCR) with 1.5 m in high and 0.1 m inside diameter as a gas-liquid contactor at 25°C and atmospheric pressure, using a simulation gaseous mixture (air, carbon dioxide) with recycle stream (circulation process). For efficient experimentation, the Taguchi method was applied for experimental design. A four factor and three levels was chosen for this study and it was exploded using L9 (34) orthogonal array design. These parameters for circulation process were namely: gas flow rate 10,15, and 20L/min, air flow rate100,150, and 200 L/h, liquid flow rate 5,10, and 15 L/min and time absorption time 30,60, and 90min. To understand the effectiveness order of different operating parameters, two factors namely, overall mass transfer coefficient (KGa ), and CO 2 loading (α) are to be exploded. A Shimadzu GC-8A Gas Chromatograph with thermal conductivity detector was used to measure the CO 2 concentration absorbed in aqueous blended solution. As per Taguchi analysis the significance sequence influencing the parameter and optimum condition can be determined. The maximum value for CO 2 loading was 3.439 (mol CO2/mol amine) at 20 L/min gas flow and 15 L/min liquid flow, and 200 L/h air flow for 60 min from absorption time. The performance was evaluated in terms of the overall mass transfer coefficient, KGav , the results show that max value of KGa was 0.08 S −1

Investigation of overall mass transfer coefficient of CO2 absorption in packed Column

Mixtures of different types of amine solution Monoethanolamine, Diethanolamine, and Triethanolamine were experimentally used to investigate the overall mass transfer coefficient (KGa) at different operating parameters. The experiments were made in a packed bed reactor (PBR) with 75 cm in high and10 cm inside diameter as a gas-liquid contactor at 25℃ and atmospheric pressure, using a simulation gaseous mixture (air, carbon dioxide) with recycle stream (semi-continuous process). Experimental design process Taguchi was employed. Four factors and three levels were chosen and exploded using L9 (3 ^4) orthogonal array design. These parameters for semi-continuous process were namely: gas flow rate 5,10,and 15 L/min ,airflow rate80,90,and 100 L/h, liquid flow rate 400,450,and 500 mL/min and time absorption time 30,45,and 60min . A Shimadzu GC-8A Gas Chromatograph with a thermal conductivity detector was used to measure the CO2 concentration absorbed in aqueous blended solution. The maximum value for CO2 loading was 8.622 (mol CO2/mol amine) at 15 L/min gas flow and 450 mL/min liquid flow and 100 L/h airflow for 60 min from absorption time. The results showed that the max value of KGa is 0.048 S-1.

Study on CO2 capture by AAILs-MDEA aqueous solution in packed tower

This study mainly uses N-methyldiethanolamine (MDEA) as the main body of absorption, and uses three kinds of AAILs(AAILs), 1-butyl-3-methylimidazolium lysinate ([Bmim][Lys]), tetramethylammonium glycinate ([N1111][Gly]) and 1-butyl-3-methylimidazolium glycinate ([Bmim][Gly]) as accelerator, respectively. That forms a new blended aqueous solution for CO2 removal. The new AAILs-MDEA aqueous solution absorbent has stronger ability to absorb CO2, faster absorption rate and lower equipment corrosion. When the gas flow rate is 500ml/min and the liquid flow rate is 150ml/min, the best removal efficiency is achieved. At 313.2K, the removal efficiency of MDEA-[N1111] [Gly] absorbent can reach 100%; the effect of the three new alkanolamine aqueous solutions on CO2 absorption is: MDEA-[N1111][Gly]>MDEA-[Bmim] [Gly]>MDEA-[Bmim][Lys].

Thermal Degradation Rate and Kinetic Modeling of CO2-Loaded Amine Solvent Blends of 2-Amino-2-methyl-1-propanol and 1-Amino-2-propanol

Employing experimental kinetics data collected in this study, a power law rate equation for the thermal degradation of 1-amino-2-propanol (A2P) and 2-amino-2-methyl-1-propanol (AMP) in CO2-loaded blended solutions are investigated. The rate experiments were carried out at 120, 135 and 150 °C to accelerate thermal degradation. Kinetic data was collected to extract the initial rate equation from aqueous blended solutions of 0.0, 0.5, 1.5, 2.0, 2.5, and 3.5 M, AMP and A2P with CO2 loadings from 0.1 to 0.6, molCO2/molAMP+A2P. The power law rate equations for each amine in the solutions, along with pre-exponential factors and activation energies for each reaction are provided. For both AMP and A2P degradation, the activation energies for the reaction between AMP, A2P and CO2 presented lower values, while the pre-exponential factors were orders of magnitude higher. The presence of the second amine in these solutions has little impact on the degradation rate of the individual amines.

Experiment and model for the viscosity of carbonated 3-(dimethylamino)propan-1-ol and 2-(ethylamino)ethanol blended aqueous solutions

The viscosities (η) of CO2-loaded 3-(dimethylamino)propan-1-ol (3DMA1P) aqueous solutions, CO2-unloaded and CO2-loaded 2-(ethylamino)ethanol (EAE)- 3DMA1P aqueous solutions were measured by using the NDJ-5S rotational viscometer. The temperature ranged from 303.2 K to 323.2 K. The mass fractions of 3DMA1P and EAE ranged from 0.3 to 0.5 and 0.01 to 0.03 respectively. The Weiland equation was used to model the viscosity and the calculated results agreed well with the experimental results. The effects of mass fractions of amines (w), temperature (T) and CO2 loading (α) on viscosity were demonstrated on the basis of experiments and calculations.

Screening tests of aqueous alkanolamine solutions based on primary, secondary, and tertiary structure for blended aqueous amine solution selection in post combustion CO2 capture

In this work, hindered primary, secondary and tertiary aqueous alkanolamine solutions with different numbers of hydroxyl groups were investigated for their initial rates of absorption and desorption which show how fast the amine solution will reach equilibrium and will be regenerated, respectively, and also investigated pKa, equilibrium solubility of CO2, heat duty (Qreg) for solvent regeneration, and heat of CO2 absorption (ΔHabs). These experimental data were used as a screening tool to enable the selection of the best amine components for designing an optimal blended aqueous amine solution system. The absorption experiments were performed at 313K and atmospheric pressure using 15% CO2 (in N2 balance) as feed gas whereas desorption experiments were performed at 363K and atmospheric pressure. Alkanolamines with a larger number of hydroxyl groups exhibited lower performance in all the CO2 capture activities because of the negative electron withdrawing effect of the hydroxyl group. Consequently, based on the results of individual primary, secondary, and tertiary aqueous alkanolamine solutions, the ones with only one hydroxyl group (2-amino-2-methyl-1-propanol (AMP), 2-(ethylamino) ethanol (EAE), and 2-(dimethylaminoethanol) (DMAE)) were selected for formulation into aqueous amine blends. Two binary aqueous amine blends of AMP/DMAE and EAE/DMAE and one ternary aqueous amine blend of AMP/EAE/DMAE at various molar ratios were tested. All solvent combinations showed better performance than 5M MEA, especially in the initial desorption rate and energy efficiency. Of these aqueous amine blends, the 2.5M AMP/2.5M DMAE exhibited the best performance with an equilibrium CO2 solubility of 0.56mol CO2/mol amine, initial absorption rate of 0.26×10−2mol CO2/min, initial desorption rate of 2.62×10−2mol CO2/min, and heat duty of 53.81kJ/mol.

Experimental and correlation study of selected physical properties of aqueous blends of potassium sarcosinate and 2-piperidineethanol as a solvent for CO2 capture

In this work, physical properties such as density, refractive index, and viscosity of aqueous blends of potassium sarcosinate (K-Sar) and 2-piperidineethanol (2-PE) were measured at temperatures ranging from 298.15 to 333.15K. Several concentrations of K-Sar and 2-PE blends were prepared in terms of mass fraction (0.04+0.16, 0.08+0.12, 0.12+0.08, 0.16+0.04, and 0.20+0), respectively. From the results, it was observed that all physical properties data decreases with the rise in temperature of the solution. While, density increases with increase in concentration of K-Sar in the aqueous blended solution, and refractive index and viscosity decrease with increase in K-Sar concentration in the solution. Both density and refractive data were correlated as a function of concentration and temperature using modified form of Graber’s equation. However, a modified Vogel–Tamman–Fulcher equation was utilized for correlating the experimental viscosity data of aqueous blend. Experimental density data were used to calculate the coefficient of thermal expansion. It increases marginally with increase in concentration and temperature. Moreover, ANOVA analysis was performed for all the physical properties data.

Polyvinyl alcohol/tannic acid hydrogel prepared by a freeze-thawing process for wound dressing applications

The objective of this study was to develop an effective, potential wound dressing consisting of a blended hydrogel of polyvinyl alcohol (PVA) and tannic acid (TA). PVA is known for its biocompatibility and hydrophilicity, and TA is known for being a natural compound which can serve as a cross-linking agent and a therapeutic agent. To prepare the PVA/TA hydrogel, a blended aqueous solution of PVA and TA was processed through three cycles of freezing at −20 ± 3 °C for 18 h followed by thawing at 25 °C for 6 h. Consequently, the PVA/TA hydrogel was successfully prepared through the freeze-thawing process. In an investigation of the hydrogel, it was found that the mechanical strength and hardness increased and that the moisture content decreased as the TA concentration was increased. Moreover, the PVA/TA hydrogel showed excellent antibacterial ability (>99.99%) and antioxidant ability (>92%).

Preparation and properties of polyvinyl alcohol/tannic acid composite film for topical treatment application

The purpose of this study was to develop an effective potential wound dressing material based on a polyvinyl alcohol (PVA) and tannic acid (TA) composite film. To prepare the PVA/TA films, PVA and TA blended aqueous solutions were cast into film form by spreading the solutions and drying them. Then the films were heat treated at 155 oC for 3 min to promote esterification between the PVA and TA. After removing un-crosslinked moieties from the films by rinsing and drying, the films were investigated by swelling behavior, FTIR spectroscopy, XRD and TGA. And, the antibacterial and antioxidant abilities of the films were also examined in this study. Through this investigation it was discovered that TA effectively acts as a functional antibacterial and antioxidant agent as well as crosslinker in the PVA/TA system. Thus, the PVA/TA composite films prepared by the casting and heat treatment method proposed in this study are expected to be used for topical medication, such as wound dressing material.

Influence of an Al-blended TiO2 photoanode on the photovoltaic properties of n-DSSCs

ABSTRACTThe performance of n-type dye-sensitized solar cells (n-DSSCs) based on a Co complex redox electrolyte were investigated with a photoanode composed with mixer consists of both TiO2 and AlCl3. The surface of TiO2 films coated on FTO glass substrates was amended by soaking them in a TiCl4:AlCl3 blended aqueous solution at different molar ratios, and calcining them to yield the surface-modified photoelectrodes (Ti:Al/TiO2). An enhancement in the power conversion efficiency 2.02% of the resulting n-DSSCs with Ti:Al (9:1)/TiO2 compared to the reference cell by the plain TiO2. The dark current measurements, incident photon-to-current conversion, and efficiency electrochemical impedance spectroscopy (EIS) revealed that the combination of a mixer onto the TiO2 film led to the delay of the charge recombination among the photo-injected electrons and Co complex redox electrolyte, resulting in an enhanced short-circuit current and open-circuit current, compared to device without surface modification.

Developing a feed forward multilayer neural network model for prediction of CO2 solubility in blended aqueous amine solutions

Absorption of carbon dioxide (CO2) in aqueous solutions can be improved by the addition of other compounds. However, this requires a large amount of equilibrium data for solubility estimation in a wide ranges of temperature, pressure and concentration. In this paper, a model based on an artificial neural network (ANN) was proposed and developed with mixtures containing monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), methanol, triethanolamine (TEA), piperazine (PZ), diisopropanolamine (DIPA) and tetramethylensulfone (TMS) to predict solubility of CO2 in mixed aqueous solution (especially in binary and ternary mixtures) over wide ranges of temperature (298.15–453.15 K), pressure (0.604–19,914 kPa), overall concentration (18.986–80 percent) and apparent molecular weight of the mixture (20.99–78.50 g/mol). The performance accuracy of the network was evaluated by regression analysis on estimated and experimental data, which were not used in network training. The optimal neural network was trained by the Levenberg–Marquardt back-propagation algorithm and the Gauss–Newton method with combination of a Bayesian regularization technique contains two hidden layers, having 8 and 4 neurons, respectively. Tan-sigmoid function was used as the transfer function of hidden and output layers.