Solvent Blends Research Articles

Experimental studies on CO2 absorption and solvent recovery in aqueous blends of monoethanolamine and tetrabutylammonium hydroxide

Solvent-based post-combustion CO2 capture process is recently carried out using chemical absorption with aqueous blends of Monoethanolamine (MEA) and Ionic Liquids (IL) as promising solvents. In the present work, the blends of MEA and TetraButylAmmonium Hydroxide [TBA][OH] have been used for CO2 absorption and desorption process. The solubility of CO2 is investigated with aqueous mixtures for various carbon loading time by varying compositions of MEA and [TBA][OH] as 30 wt%, 28 wt%, 25 wt%, 20 wt% and 0 wt%, 2 wt%, 5 wt%, 10 wt% respectively. It increases with increasing IL concentration for all the aqueous mixtures. The solvent regeneration was also studied at different temperatures in order to recover and reuse the solvent for cyclic absorption. The slight decrease in CO2 solubility was noted for 20 wt% MEA +10 wt% [TBA][OH] mixture. However, this mixture exhibits higher absorption/desorption rate and regeneration efficiency than other mixtures. The regeneration energy of this mixture was also calculated as 28.6 kJ/mol of CO2, which is 32% less than that of baseline 30 wt% MEA. Furthermore, the physicochemical properties such as density, viscosity and surface tension for all the solvent blends were studied experimentally.

Interfacial properties between ionic‐liquid‐based electrolytes and lithium‐ion‐battery separator

AbstractFor lithium salts, ionic liquids (ILs) are promising alternatives to conventional solvents in lithium‐ion batteries (LIBs) due to a more favorable high‐voltage operating window, and due to improved safety through reduction of flammability. Toward better understanding of wetting properties of IL‐based electrolytes on a LIB separator, wetting properties affect electrochemical performance, experimental studies were made to determine the influence of solvent, lithium‐salt type and salt concentration. Surface tensions and advancing contact angles were measured for two pure ILs ([C4C1im][BF4] and [C4C1im][OTf]) and for four IL/alkylcarbonate solvent blends (1:1 mass ratio, [C4C1im][BF4]/PC, [C4C1im][BF4]/DMC, [C4C1im][OTf]/PC, and [C4C1im][OTf]/ DMC) with several concentrations of a lithium salt (LiClO4, LiPF6, and LiTFSI). A significant improvement of wettability of pure ILs was observed by adding DMC, while adding PC with surface tension higher than that of pure ILs is detrimental to wetting behavior. Contact angles decrease by adding LiTFSI but show almost no change upon addition of LiPF6 or LiClO4. Surface tensions follow the same trend as that for contact angles. Incorporation of TFSI− anion gives favorable separator wettability. Estimates were made for interfacial properties of the separator (dispersive and polar components of the surface free energy for solid‐vapor, for liquid–vapor, and for solid–liquid interfacial free energy).

Investigation of CO2 Solubility in Blends of AMP and HMDA Solvents: Thermodynamic Modeling Based on the Deshmukh-Mather Model

Among the various methods for CO2 removal from the atmosphere, CO2 absorption is considered as the most applicable one. Although several studies have been performed on CO2 absorption by using chemical solvents, there are not many studies on using improved absorbents. Therefore, the aim of this study was to measure the solubility of CO2 in utilized aqueous blends of 2-amino-2-methyl-1-propanol (AMP) and hexamethylenediamine (HMDA). In the present research, the equilibrium set up for measuring CO2 solubility in aqueous solvents was assembled. CO2 solubility experiments were carried out over a various range of CO2 partial pressures (8.44, 25.33, and 42.22 kPa) temperatures (303, 313, and 323 K) and solvent concentration (0.4, 1.8, 2, and 3 M). The results showed that increasing CO2 partial pressure or decreasing the temperature would lead to an increase in CO2 loading. Furthermore, with increasing HMDA concentration, CO2 loading reached a maximum value before it followed a slight decrease. The experimental results were fitted to the thermodynamic Deshmukh Mather model and the required parameters in this model were generated. The results showed that there is a good agreement between theoretical and experimental results of CO2 loading.

Biogas upgrading through blends of deep eutectic solvents and monoethanol amine: 4 E analysis (energy, exergy, environmental, and economic)

Blends of monoethanol amine (MEA) with an aqueous deep eutectic solvent (DES), with MEA present in various proportions of 5, 10, and 15 wt%, are used in process design for biogas upgrading.

PVDF/CNF/IL composite film for shielding of microwave radiation

In this work materials have been used in the form of conducting polymer composite film for covering of different electrical and electronic equipment to provide effective electromagnetic interference (EMI) shielding. Pre localized CNF (CNF) powder will be mixed with Poly (vinylidene fluoride) (PVDF) and Ionic Liquid (IL) using solvent blending method to form a series of PVDF/CNF/IL composite films with different concentration of CNF and IL. Obtained composite films were characterized with Scanning Electron Microscopy (SEM) and Differential scanning calorimetry (DSC) for surface morphology and thermal analysis. Fabricated films were also examined for their mechanical properties. The dielectric properties of the film were measured with the help of impedance analyser. After this using dielectric properties of the films shielding effectiveness are calculated in the range of 100 KHz to 10 MHz. The fabricated film with composition of 60/10/30 exhibits the shielding effectiveness of 32 dB to 40 dB in entire frequency range and also has the elongation of 31%. The key advantage of obtained composite films is there light weight and flexibility can be used to shield small electronic equipment.

Flexible composite film for shielding of microwave radiation

Electromagnetic interference (EMI) disrupts the working of electronic devices and circuits. In this work materials have been exploited in the form of conducting polymer composite film to give effective EMI shielding properties. Pre localized Graphite(Gr) powder will be mixed with Poly vinylidene fluoride (PVDF) and Ionic Liquid (IL) using solvent blending method to form a series of PVDF/Gr/IL composite films with different concentration of Gr and IL. Obtained films were characterized with Scanning Electron Microscopy (SEM) and Differential scanning calorimetry (DSC) for surface morphology and thermal analysis. The dielectric properties of the film were measured through which shielding effectiveness of the film is calculated for both near field and far field region in the frequency range of 100 KHz to 10 MHz. The composition with 70/10/20 exhibits maximum shielding effectiveness of 35 dB, 120 dB and 40 dB for plane wave, electric field and magnetic field respectively. The fabricated films exhibit excellent EMI Shielding properties with extra advantage of low cost and flexibility.

Experimental and artificial neural network based analysis of solvent blends for dewaxing of crude oil

Sustainability in flow condition by maintaining the pour point and cloud point in storage and transportation of crude oil is always a challengeable task for petroleum industry. Thus solvent dewaxing is an effective process used in oil refinery for monitoring before the transportation of crude oil in pipelines with an efficient and selective blended chemical. The present work describes the solvent dewaxing process through by analysis of basic fundamental interactions with computations of different acoustic parameters in presence of a high frequency ultrasonic wave. Experiments were performed to investigate the molecular interaction in rheological properties of waxy crude oil by blended solvent over a temperature range of 293 K to 323 K. The wax yield efficiency in the crude oil indicates that the performance of solvents blends depends on its mole fraction, compatibility of blends and on temperature of treatment. Addition of sonicated solvent blends in the ratio of 10:1, 15:1 and 20:1 improves flow conditions in crude oil pipe lines and increases its pour point. The sonication study was also designed by artificial neural network (ANN) model using R-Software which has been developed for ultrasonic velocity and other related parameters. The proposed ANN model for dewaxing of crude oil with blended solvent in different operating conditions provides comparable results with average absolute deviation (AAD) less than 0.5%.

Surfactant for petroleum demulsification, structure, classification, and properties. A review

Crude oil as a complex fluid often consists of colloidal particles. These colloidal particles are made up of asphaltenes and resins diffused in a blend of aliphatic and aromatic solvents. At various stages of crude oil production, there is usually an occurrence a water-in-oil emulsion. The stability of the emulsion formed is dependent on the occurrence of the interfacial barrier which prevents the coalescence of the dispersed water droplets. Several operational difficulties are often encountered during crude oil processing as a result of the presence of water. These difficulties range from corrosion in equipment and pipelines as well as an increase in the production cost. Hence, to mitigate these economic and operational challenges, it is crucial to ensure that the water is separated from the crude oil prior to transporting or refining the oil. Demulsification using surfactant is one of the effective techniques used for the separation of crude oil from water. This paper presents a short review of the various application of surfactants for demulsification, their structure, classification as well as their properties. In addition, the mechanism and techniques for demulsification of crude oil were also presented.

Association Constant And Free Energy Change Properties Of Sodium Salt Of 1-Butane Sulphonic Acid In Aqueous Meoh And Aqueous Dmso Composition

Various elements similar to density, viscosity, medium dielectric constant, ion-solvent relationships, and measurements of solvent-solvent, form properties of ion-conductance and ion solvation related to different solvent electrolytes. In solving it, ion-solvent relations pacify the ion. In the analysis of ion solvent associations and ion solvation activities, conductance data and association constant figures of distant electrolytes are used. Conductance and ion solving properties of 1-butane sulphonic acid sodium salt measured in aqueous methanol and aqueous DMSO of varying composition in the 298 K to 318 K-temperature range. Limiting molar conductance, ion pair interaction constants, KA using Shedlovsky limiting law to work out. With the percentage of water in the solvent mixture, ∧0 increases. In 80% aqueous-methanol mixture, KAvalue and free energy changes are maximum, indicating that ion-solvent interactions are maximum in this composition of solvent blend and ion conductance properties as a purpose of clear ion-solvent links, including structural influence.

Modified Lyocell process to improve dissolution of cellulosic pulp and pulp blends in NMMO solvent

Utilization of low-cost paper grade pulp is not feasible in Lyocell process due to presence of metallic and hemicellulose impurities that degrade cellulose and N-methyl-morpholine-N-oxide and lower the onset temperature of dope to initiate runway reaction. Conventional Lyocell process is restricted to use good quality dissolving grade pulp for safety reasons. To overcome this limitation, modified Lyocell process is demonstrated by pretreating pulps to remove metallic and hemicellulose impurities. Effectiveness of modified Lyocell process for faster dissolution and impurities removal for pulps/pulp blends is studied. Pretreatment of pulp blends significantly reduce impurities by 14–32% and improve swelling of pulp results in faster dissolution and safer process. Biopolymer prepared from modified process reduces undissolved particles by 50% and impurities by 30% thus improving overall quality and spinnability. This concept provides practical solution for using paper grade/impure pulps and making it more economical, faster dissolution and safe as compared to conventional process.

Comparative Extraction Performance of Solvent Systems in the Extraction and Characterization of Pectin from Prosopis Africana Seed Gum

Pectin was separately extracted in warm water bath from sun-dried and crushed Prosopis africana seed gum, using 0.05 M solutions of HCl, H2SO4, CH3COOH, C6H8O7 and a 3:2 blend of (H2SO4: C6H8O7). The physicochemical properties of pectin extracted from the Prosopis africana seed gum shows the following: colour varied from beige-brown to wheat brown, equivalent weight (1,818.18 mg/mol to 25,000 mg/mol), methoxyl content (0.124 % to 1.705 %), moisture content (12 % to 38 %) and ash content (2 %) for all the solvent system used. Also, the comparative solvent performance shows that the H2SO4:C6H8O7 solvent blend was the most effective for pectin extraction followed by the solvent HCl and H2SO4, while C6H8O7 was the least effective. The comparative pectin yield of Prosopis africana seed gum using selected acid solvent ranged from 6.94 % to 15.28 %. Among the solvents under study, the H2SO4:C6H8O7 solvent blend gave the highest pectin yield (15.28 %) with beige-brown, low methoxyl pectin of high purity and could be used as a functional food ingredient domestically and industrially

Improving superhydrophobicity of polydimethylsiloxanes using embedding fluorinated polyhedral oligomeric silsesquioxanes cages

Improving the superhydrophobicity of polydimethylsiloxane (PDMS) is a current interest in a wide range of applications from biomedical to aerospace. Although many fabrication techniques are available to improve the superhydrophobicity of PDMS, a significant problem occurs when the fabrication technique applies as a scalable but simple one. Here, we have described simple methods to achieve superhydrophobicity of PDMS using short-chained fluorinated polyhedral oligomeric silsesquioxanes (FPOSS). Two species of FPOSS were incorporated into PDMS using four different methods; non-solvent blending, solvent blending, spraying FPOSS/PDMS solution onto a partially cured PDMS matrix and spraying only FPOSS solution onto partially cured PDMS surfaces. Among two FPOSS species, spraying FPOSS onto partially cured PDMS produced a superhydrophobic surface with a static water contact angle of 167° ± 1°. Trifluoropropylisobutyl POSS (TFP) resulted in a higher hydrophobicity than trifluoropropyl POSS cages (CM). The multi-scale structured surface morphology, compatibility of functional groups attached to FPOSS and the fluorine content have shown a significant contribution on the superhydrophobicity in FPOSS/PDMS systems. Amorphous nature of the PDMS has improved upon incorporating FPOSS. Hence, this work presents a detailed study on the effect of the preparation method of FPOSS/PDMS composite on its superhydrophobicity.

Propylene carbonate-nitrile solvent blends for thermally stable gel polymer lithium ion battery electrolytes

Gel polymer electrolytes (GPEs) based on poly (vinylidene difluoride-co-hexafluoropropylene) (PVdF-HFP) containing propylene carbonate (PC), isobutyronitrile (IBN) and trimethyl acetonitrile (TMAN) solvent blend electrolytes were developed to enhance high temperature electrochemical performance and to improve safety of LiNi3/5Mn1/5Co1/5O2 (NMC622)‖graphite lithium ion battery (LIB) cells. These liquid electrolytes (LE) consist of lithium bis(trifluoro-methane)sulfonimide (LiTFSI) as conducting lithium salt and PC/nitrile (1:1, v/v) solvent blends. Ethylene sulfite (ES) and vinylene carbonate (VC) were used as solid electrolyte interphase (SEI) forming additives and contributing to an excellent cycling stability of electrolytes comprising nitrile solvents in NMC622‖graphite cells. Electrochemical impedance spectroscopy (EIS), pulsed field gradient nuclear magnetic resonance spectroscopy (PFG NMR) and relative permittivity determination reveal remarkable ion conducting properties of IBN and TMAN solvents. Since their electrolytes are incompatible with lithium metal electrodes, their electrochemical stability window (ESW) was determined using lithiated lithium titanate (Li7Ti5O12) (LTO) as counter and reference electrodes and the obtained values were confirmed by quantum mechanical computation. Differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC) confirmed significantly improved safety of IBN and TMAN containing electrolytes. Therefore, PVdF-HFP-based GPEs containing PC/nitrile solvent blends are a promising alternative to SOTA electrolyte for battery cycling at elevated temperature (60 °C) in NMC622‖graphite cells.

Amphiphilic diblock copolymers inhibit the formation of encrustation on the surface of biodegradable ureteral stents in vitro and in vivo

Ureteral stents have been used to treat a variety of urinary diseases for decades. However, the complication of encrustation often impedes its therapeutic effectiveness and service after indwelling in human body. In the present study, in order to surmount this problem, amphiphilic block copolymer, methoxypoly (ethylene glycol)-b-poly (Ɛ-caprolactone) (mPEG-PCL), was used to endow poly (l-lactide-ran-Ɛ-caprolactone) (PLACL) with hydrophilicity by solvent blending. The hydrophilicity, degradability, anti-encrustation (both in vitro and in vivo) and biocompatibility of the developed ureteral stents were assessed using water contact angle, electronic universal material testing machine, SEM, EDS, ICP-OES, dynamic urinary circulation model and a rat model. A progressive increase in the water contact angle and degradation rate was observed with the increase in mPEG-PCL concentration from 1 % to 5 % w/w in the mPEG-PLACL blends. In addition, according to ICP-OES results, approximately 38.86 % Ca and 60.55 % Mg was inhibited after 7 days immersion in dynamic urinary circulation model. Also, in the seventh week of indwelling the developed ureteral stents in rat model, compared with the hydrophobic PLACL, 71 % Ca and 93 % Mg was inhibited. Moreover, histological evaluations showed that mPEG-PCL/PLACL blends decreased tissue inflammation with favorable biocompatibility. As a result, this developed hydrophilic ureteral stents had great potential to become an ideal urological medical device.

Carbon dioxide capture using liquid absorption methods: a review

Anthropogenic emissions of greenhouse gases into the atmosphere is inducing global warming, ocean acidification, polar ice melting, rise in sea level, droughts and hurricanes, thus threatening human health and the global economy. Therefore, there is a need to develop cost-effective technologies for CO2 capture. For instance, solution absorption is promising due to a large processing capacity, high flexibility and reliability, and rich experience in engineering applications. Nonetheless, actual commercial solutions, solvents and processes for CO2 capture suffer from slow reaction kinetics, low absorption capacity, high-energy consumption, susceptibility to corrosion, toxicity, low stability and high costs. Therefore, current research focuses on developing more economical, effective, green and sustainable technologies. Here we review 2015–2020 findings on CO2 capture using liquid absorption methods. Methods are based on various solutions, solvents and processes such as carbonate solution, ammonia solution, amine-based solution, ionic liquid, amino acid salt, phase changing absorbent, microcapsulated and membrane absorption, nanofluids and phenoxide salt solution. We discuss absorption performance, absorption mechanism, enhancement pathways and challenges. Amine- and NH3-based absorbents are widely used, yet they are limited by high regeneration energy, corrosiveness and degradation, reagent loss and secondary pollution caused by NH3 escape. Phase changing absorbents are getting more attention due to their lower cost and lower energy penalty. The incorporation of membrane and microencapsulation technologies to absorbing solvents could enhance CO2 absorption performance by reducing corrosion and increasing selectivity. Adding nanoparticles to solvents could improve CO2 absorption performance and reduce energy requirement. Besides, solvent blends and promoter-improved solvents performed better than single and non-promoted solvents because they combine the benefits of individual solvents and promoters.

Experimental results of amine emission from the CO2 capture process using 2-amino-2-methyl-1-propanol (AMP) with piperazine (PZ)

The use of amine scrubbing methods for reducing CO2 emission from burning fossil fuels is growing in popularity. A major challenge of carbon capture methods using amines is high energy consumption. Moreover, the emission of amines from the carbon capture plant gains increasing attention due to environmental concerns. The amines may evaporate from the solution or be released in the form of an aerosol and enter the atmosphere.In order to determine the amines emission, experimental research was conducted using a process development unit. The composition of the gases from the absorber and desorber were measured using a Fourier Transform Infrared (FTIR) gas analyser. A solvent blend of 2-amino-2-methyl-1-propanol (AMP) and piperazine was utilised. Synthetic flue gas containing 12.7–12.9 % vol. (dry basis) of CO2 was directed to the absorber with a flow rate of 100 m3/h. Fresh water was supplied to the top of the absorber to maintain the water balance. No other form of water wash was used.The major components that were emitted together with the treated gas were ammonia and AMP. The produced CO2 contained traces of amine, ammonia and formic acid. The concentration of other degradation products was below the limit of quantification. Increasing the lean solvent temperature by 15 °C resulted in an increase in AMP emission by over 50 ppm. By analysing the vapour pressure literature data with obtained results, the emission was considered mainly as vapour-based. Water dosing at the top of the absorber proved to be effective in reducing amine emissions.

Self-stratified bio-based coatings: Formulation and elucidation of critical parameters governing stratification

Self-stratification is an innovative one-step process used to design multi-functional coatings gathering simultaneously in a one-pot formulation the primer, the intermediate layer and the top coat properties. Many self-stratifying coatings contain oil-based epoxy resins but the literature is scarce in the development of “greener” solutions. In this work, silicone resins and bio-based epoxy resins were dissolved in various solvent blends, applied on a composite substrate and cured under different conditions to obtain stratified coatings. To reach a perfect stratification, the influence of various parameters including (i) the surface tension and the polarity of the resins, (ii) the solvents volatility, (iii) the curing temperature and (iv) the reactivity of the epoxy/amine reaction was studied by a systematic approach. In accordance with the literature, it was demonstrated that a large difference in surface energy and polarity favors resins separation. The volatility of the solvent blend was also shown to be a key factor in the stratification process. However, the predominant parameter, rarely taken into account, is the curing temperature, which impacts the cross-linking reaction of the epoxy resin. The increase in molecular weight (MW) of epoxy resins due to the cross-linking reaction favors the incompatibility between resins by increasing the difference in MW between epoxy and silicone resins. Thus, optimization of process conditions allowed the design of perfectly stratified bio-based epoxy/silicone coatings. The mechanism of film stratification was also elucidated thanks to in-situ analyses.

Novel insights into the role of solvent environment in perovskite solar cells prepared by two-step sequential deposition

We use a two-step spin-coating method to construct efficient and non-hysteresis planar perovskite solar cells (PSCs). The influence of solvent environment on the precursor configuration, perovskite crystallization kinetics, and photoelectric properties of the PSCs are systematically studied, resulting in novel insights into the function of dimethyl sulfoxide/dimethylformamide (DMSO/DMF) blend solvent (BS). The DMSO/DMF BS promotes the construction of porous “rod-like” precursor film, which provides sufficient space for lattice expansion and orientation selection during perovskite growth, thus producing high-quality perovskite absorbers with high crystallinity. Moreover, DMSO/DMF BS also induces the formation of amorphous lead chloride (PbCl2) and stores it in the final perovskite film, effectively passivating perovskite defects, extending carrier lifetime, and significantly improving device performance. As a result, a DMSO/DMF-based planar PSC is prepared with reverse efficiency of 19.69% and forward efficiency of 19.54%. Moreover, devices show a good stability over 500 h and reproducibility in 20 pieces fabricated with the same procedure. This study provides a new concept for the preparation of high-quality perovskite absorbers and highly efficient planar PSCs, and represents an important contribution toward determining the potential influence of solvent engineering on perovskite crystallization kinetics.

Recycling of used polyethylene through solvent blending of plasticized polyhydroxybutyrate and its degradation potential

The use of plastics has increased in every aspect of our daily activities, they are cheap, durable, and resistant to corrosion, lightweight, degradation and can be readily moulded into various products. Solution to non-renewable source, management of plastics wastes and disposal has posed a great challenge to environments and the researchers on the alternative means. As such, biodegradable plastics come forth, as adequate substitute. The aim of this study is to blend degradable polymer, polyhydroxybutyrate (PHB) with used polyethylene (UPE) as a means of recycling. The PHB granules was weighed and UPE in percentages (5, 10, 15, 20 and 25 %). Solvent casting method (xylene) was used. The FTIR of the blends showed peaks at 2210.229 cm−1 which correspond to peak of commercial PHB used. X-ray diffraction (XRD) revealed peaks at 38° indicated C-H-O=C hydrogen bond between the C=O group and CH3. The proportion of PHB blended with used PE at 15 % (15 g U/PE, 3 g PHB, and 2 g plasticizer) in the blends gave the highest maximum tensile strength. The water absorption for all the U/PHB blends was higher compared to the UPE and PHB blended .It was observed that weight loss increased as the number of days increases from 30 days to 90 days in the soil degradation study while there was reduction in the sizes and weights of the composite at the end of 21 days degradation study in slurry.

Graphene/polyaniline nanocomposites: effect of in-situ polymerization and solvent blending methods with dodecylbenzene sulfonic acid surfactant

Polyaniline (PANI) has fascinated considerable interest from industrial and academic researchers due to their great potential in many electronic applications. The present study aims to enhance the electrical and thermal properties of the graphene/PANI nanocomposites using different fabrication methods and modifications in the nanocomposites formulation. Comparison on the properties of graphene/PANI nanocomposites produced by in-situ polymerization and solvent blending methods and also the effects of dodecylbenzene sulfonic acid (DBSA) surfactant are investigated. Electrical conductivity, thermal conductivity, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to characterize the sample. Results showed that graphene/PANI nanocomposites produced by the in-situ polymerization method have better electrical conductivity, thermal conductivity and thermal stability if compared to that of the solvent blending method. The in-situ polymerization method exhibits a smaller diameter size of PANI fiber and good dispersion of graphene filler. Furthermore, the addition of DBSA surfactant in the graphene/PANI nanocomposites developed homogeneity and uniform dispersion of the graphene filler within the PANI matrix. In conclusion, graphene/PANI with surfactant nanocomposites produced by the in-situ polymerization method showed higher electrical and thermal conductivity by 10% and 6%, respectively, if compared to the in-situ polymerization without surfactant. Thermal stability also showed improvement with the addition of surfactant.