Isopropanol Solution Research Articles

Quantitative surface and Hirshfeld surface analysis of nicorandil molecule and further insight into its solubility in several aqueous protic and aprotic cosolvent solutions

The quantum-chemical quantities of highest negative surface electrostatic potential and lowest surface average local ionization energy as well as Hirshfeld surface were used herein to explain the electrostatic features of both basicity and acidity of nicorandil molecule. The primary electrophilic and nucleophilic sites are the -Nand > NH groups, respectively. According to the nicorandil solubility in solutions of isopropanol (1) + water (2), ethanol (1) + water (2), DMF (1) + water (2), and methanol (1) + water (2), preferential solvation of nicorandil was investigated using the famous inverse Kirkwood-Buff integrals approach. In poor water composition areas, nicorandil was surrounded preferentially by organic solvent, showing the selective solvation of nicorandil by methanol/DMF/ethanol/isopropanol. This performance was due to high basicity of organic solvents compared with water, which favors interactions with nicorandil's acidic groups. The Hansen solubility parameter was used to evaluate the performance of nicorandil solubility in depth. The derived dissolution Gibbs energy change, enthalpy and entropy indicated that the solubilization capacity improved with increasing methanol/DMF/ethanol/isopropanol compositions. As the proportions of methanol/DMF/ethanol/isopropanol rose, analysis of enthalpy–entropy compensation revealed a shift in main dissolving mechanism from enthalpy-driven to entropy-driven (alcohol solutions) or from entropy-driven to enthalpy-driven (DMF solutions).

Inter-/intra-molecular interactions, preferential solvation, and dissolution and transfer property for tirofiban in aqueous co-solvent mixtures

Using Hirshfeld surface, interaction region indicator and quantitative molecular surface analysis, the microscopic electrostatic features of basicity and acidity of the tirofiban molecule were clearly demonstrated. Both the O atoms in >SO2 and H atom in –COOH serve as primary electrophilic site and nucleophilic site, respectively. Utilizing solubility data for tirofiban in four different water-based co-solvent mixtures {isopropanol/ethylene glycol (EG)/methanol/ethanol (1) + water (2)}, the inverse Kirkwood–Buff integral method was utilized to determine the preferred solvent for the tirofiban solvation according to the results of preferential solvation analysis. In water-rich composition ranges, the drug is surrounded by water, whereas in isopropanol/methanol/ethanol-intermediate and -rich composition ranges, the drug is surrounded by ethanol/methanol/isopropanol. Isopropanol solutions had the largest magnitude of preferential solvation. Alcohols may have a greater basicity that enhances interactions with the Lewis acidic function groups of tirofiban, giving rise to selective solvation of this drug. The linear solvation energy relationships were used to determine the relative impact of solvent-solvent and solvent-solute interactions in determining the variation of solubility magnitudes. The properties of dissolution and transfer, such as entropy, enthalpy and Gibbs energy change were computed. Entropy-driven and enthalpy-driven mechanisms were shown to be responsible for the change in tirofiban solubility in the four aqueous solutions, according to the enthalpy–entropy compensation analysis.

Enhancing Performance of Thin-Film Nanocomposite Membranes by Embedding in Situ Silica Nanoparticles.

In this work, silica nanoparticles were produced in situ, to be embedded eventually in the polyamide layer formed during interfacial polymerization for fabricating thin-film nanocomposite membranes with enhanced performance for dehydrating isopropanol solution. The nanoparticles were synthesized through a sol-gel reaction between 3-aminopropyltrimethoxysilane (APTMOS) and 1,3-cyclohexanediamine (CHDA). Two monomers—CHDA (with APTMOS) and trimesoyl chloride—were reacted on a hydrolyzed polyacrylonitrile (hPAN) support. To obtain optimum fabricating conditions, the ratio of APTMOS to CHDA and reaction time were varied. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to illustrate the change in morphology as a result of embedding silica nanoparticles. The optimal conditions for preparing the nanocomposite membrane turned out to be 0.15 (g/g) APTMOS/CHDA and 60 min mixing of APTMOS and CHDA, leading to the following membrane performance: flux = 1071 ± 79 g∙m−2∙h−1, water concentration in permeate = 97.34 ± 0.61%, and separation factor = 85.39. A stable performance was shown by the membrane under different operating conditions, where the water concentration in permeate was more than 90 wt%. Therefore, the embedment of silica nanoparticles generated in situ enhanced the separation efficiency of the membrane.

Effects of monomer rigidity on microstructures and properties of novel polyamide thin-film composite membranes prepared through interfacial polymerization for pervaporation dehydration

In this study, thin-film composite (TFC) membranes were produced through interfacial polymerization between diamine and trimesoyl chloride on a polyetherimide (PEI) support. The TFC membranes with different diamines, 4,4′-((propane-2,2-diylbis(4,1-phenylene))bis(oxy))dianiline (BAPP), 4,4′-((methylene bis(4,1-phenylene))bis(oxy))dianiline (MPDA), and 6,6′-bis(4-aminopheoxy)-4,4,4′,4′,7,7′-hexamethyl-2,2′-spirobichroman (SBC), were denoted as TFCPEI/B, TFCPEI/M, and TFCPEI/S, respectively. These three aromatic diamines have different central moieties that affect reactivity during the interfacial polymerization reaction. The crosslinking degree of the TFC membranes increased in the following order: TFCPEI/S < TFCPEI/M < TFCPEI/B. Positron annihilation lifetime spectroscopy analysis also unveils that TFCPEI/B had the lowest free volume. These results reveal that the appropriate steric structure of the diamine molecules can create less compact structure without impeding the formation of the crosslinked polyamide selective layer. Moreover, the TFCPEI/B membrane had a flux of approximately 705 ± 46 g∙m−2 h−1, and the water concentration in the permeate was maintained at approximately 99.8 wt% at 25°C during the 70 wt% isopropanol solution dehydration. Furthermore, the TFCPEI/B membrane can be operated under broad operating conditions and possesses high long-term stability.

Sub-Nanosecond Digital Signal Processing of Photomultiplier Tube Response Enabling Multiphoton Counting in Raman Spectroscopy.

This paper introduces a novel approach to achieve multiple photon counting for Raman spectroscopy. The multiphoton counting process is made possible by recording and analyzing the photomultiplier tube response to each pulse of a pulsed laser in a time-resolved Raman spectroscopy system. Conventional Raman spectroscopy typically considers photon arrivals as binary events assessed by a single threshold. Hence, the conventional algorithm ignores the fact that multiple photons could arrive within the same response, sacrificing potential signal gain. In this work, a high-speed data acquisition system and multiple threshold digital signal processing counting algorithm are employed to facilitate multiphoton counting, a data processing approach that differentiates photon arrival events by amplitude and time and contributes to improved Raman detection sensitivity. The multiphoton counting algorithm enables lower concentration detection, greater sensitivity, shortens experiment duration, and improves noise rejection. Results from analyses of aqueous solutions of nitrate, isopropanol, and rhodamine 6G demonstrate the versatility and effectiveness of this algorithm. The algorithm increased system sensitivity by ∼ 2.0-, 2.0-, and 3.1-fold, compared to traditional single-threshold analyses of the same data for tests performed on nitrate, isopropanol, and rhodamine 6G, respectively. Results also demonstrated that the multiphoton counting algorithm increases the upper analysis limit for high Raman-yield compounds, shifting the saturation threshold to a higher concentration in typical concentration versus intensity calibration curves.

Vacuum-Assisted Interfacial Polymerization Technique for Enhanced Pervaporation Separation Performance of Thin-Film Composite Membranes.

In this work, thin-film composite polyamide membranes were fabricated using triethylenetetramine (TETA) and trimesoyl chloride (TMC) following the vacuum-assisted interfacial polymerization (VAIP) method for the pervaporation (PV) dehydration of aqueous isopropanol (IPA) solution. The physical and chemical properties as well as separation performance of the TFCVAIP membranes were compared with the membrane prepared using the traditional interfacial polymerization (TIP) technique (TFCTIP). Characterization results showed that the TFCVAIP membrane had a higher crosslinking degree, higher surface roughness, and denser structure than the TFCTIP membrane. As a result, the TFCVAIP membrane exhibited a higher separation performance in 70 wt.% aqueous IPA solution at 25 °C with permeation flux of 1504 ± 169 g∙m−2∙h−1, water concentration in permeate of 99.26 ± 0.53 wt%, and separation factor of 314 (five times higher than TFCTIP). Moreover, the optimization of IP parameters, such as variation of TETA and TMC concentrations as well as polymerization time for the TFCVAIP membrane, was carried out. The optimum condition in fabricating the TFCVAIP membrane was 0.05 wt.% TETA, 0.1 wt% TMC, and 60 s polymerization time.

PYROLYTIC MASS-SPECTROMETRY OF THE OLIGOISOPRENE WITH OF TERMINAL HYDROXYL GROUPS

Pyrolytic mass spectrometry was used to evaluate the effect of terminal hydroxyl groups on the composition of thermal degradation products of oligoisoprene obtained using hydrogen peroxide as an initiator in the isopropyl alcohol solution. To interpret the mass spectra of the oligomer, the mass spectra of some low molecular weight alcohols were used. Oxygen-containing groups were found in the mass spectrum of the oligomer, confirming the presence of two types of hydroxyl groups. Peak m/z = 85 corresponds to the fragment from the terminal unit of isoprene directly connected with the primary hydroxyl group, and peak m/z = 127 does the same unit with the terminal fragment of isopropyl alcohol with the tertiary hydroxyl group. This conclusion is confirmed by the presence of peaks resulting from the transformations of the end groups of atoms in the oligomer, which are modeled by the corresponding low molecular weight alcohols.

Characterization and Crystal Nucleation Kinetics of a New Metastable Polymorph of Piracetam in Alcoholic Solvents.

A new polymorph of the drug active pharmaceutical ingredient piracetam (Form VI) has been discovered and characterized by X-ray powder diffraction (PXRD), solid-state Raman, attenuated total reflectance infrared spectroscopy, and differential scanning calorimetry. The PXRD diffractogram of Form VI shows a distinct peak at 24.2° (2θ) that distinguishes it from the previously known polymorphs and solvates. Form VI is metastable with respect to the previously known polymorphs Form II and Form III; in ethanol solution at 288 K, Form VI transforms into Form II within 15 min, while in isopropanol solution Form VI is kinetically stable for at least 6 h. A total of 1200 crystal nucleation induction time experiments of piracetam in ethanol and isopropanol solutions have been conducted, in sets of 40–80 repeat experiments carried out at different temperatures and solute concentrations. Each solution nucleated as a single polymorph, and each set of repeat experiments resulted in different proportions of Form II, Form III, and Form VI, with Form VI dominating at low nucleation temperatures and Form II at higher nucleation temperatures. The induction time data for Form VI at 288 K have been evaluated within the framework of the classical nucleation theory. At equal driving force, nucleation of Form VI is less obstructed in ethanol than in isopropanol, as captured by a lower interfacial energy and higher pre-exponential factor in ethanol. The proportion of Form VI obtained at a comparable driving force increases in the order ethanol < isopropanol.

Hybridization of supercritical water oxidation and gasification processes at pilot plant scale

The combination of SCWO with SCWG forms a unique system that has been tested in the present study at pilot plant scale using a single reactor with a flowrate of up to 150 kg/h. SCWO of a highly concentrated ethanol solution takes place in the first section of the tubular reactor, rising temperature. Then, an isopropanol solution is gasified into the second section to prevent any further increments of the temperature and producing hydrogen. The effect of different flowrates, the addition of different oxidant amounts and the preheating temperature of the gasification feed have been evaluated obtaining a gas effluent containing 10.7% H2 and 17.2% CH4 in the best conditions that have could tested, although better results would be obtained if processes could be carried out at more extreme conditions based on literature evidences.

Characterization of eosin red and hibiscus sabdariffa-based dye-sensitized solar cells

The fabrication of dye-sensitized solar cell (DSSC) using Eosin red and Hibiscus sabdariffa has been conducted in this study. Eosin red and Hibiscus sabdariffa dyes were used as photosensitizers. The dyes were prepared by dissolving 1 g each of Eosin red and Hibiscus sabdariffa in 30 ml of isopropyl alcohol (IPA) solution. A semiconductor TiO2 paste was deposited on FTO glass using doctor blade technique and its films were dipped in the dye solutions for 10 h. This DSSC consists of working electrode and counter electrode sandwiched together. The TiO2 powder used was identified using X-Ray diffractometer. The optical and functional groups of the dyes were characterized using UV–Visible Spectrophotometer and FTIR Spectrometer respectively. The electrical characterization was carried out using solar simulator under AM 1.5 and Keithley Multimeter. The results of the current-voltage measurements of Eosin red-based DSSC had short circuit current of 0.035 mA and an open circuit voltage of 0.34 V with maximum current of 0.025 mA and a maximum voltage (Vmax) of 0.20 V. Hibiscus Sabdariffa-based DSSC has short circuit current (Jsc) of 0.075 mA and an open circuit voltage (Voc) of 0.38 V with maximum current (Imax) of 0.06 mA and Vmax of 0.20 V. The efficiencies of the two cells were estimated to be 1×10−6 % and 5×10−7 % for Hibiscus sabdariffa and Eosin red-based DSSCs respectively. This supports that natural sensitizer that is available; ecofriendly and affordable can favorably replace the synthetic dye under good conditions.

Development and Evaluation of Ceftazidime Loaded Microemulsion for Parenteral Drug Delivery System

The goal of this study was to develop a parenteral microemulsion formulation of Ceftazidime antibiotics. The ceftazidime sparingly soluble in organic solvent like ethanol, DMSO, and dimethyl formamide were determined. For biological experiment, organic solvent- free aqueous solutions of ceftazidime (hydrate) are prepared by directly dissolving the crystalline compound in aqueous buffer. The peudo ternary phase diagrams of oil, surfactant, cosurfactants (Butanol/ Isopropyl alcohol mixture) and water were constructed to identify boundaries for microemulsion existence. Ceftazidime microemulsion particle size, solution viscosity and conductivity were evaluated. The microemulsion stability and haemolytic activity were examined after dilution in 5% dextrose solution for injection to 1 mg/mL ceftazidime. In vitro haemolysis studies indicated that Ceftazidime microemulsions were well tolerated by erythrocytes. The novel microemulsion formulation of Ceftazidime was developed that is suitable for parenteral administration. This new formulation could potentially have less vehicle-associated side effects that current commercial formulation of Ceftazidime based on Cremophor® EL and isopropyl alcohol solution.

Highly efficient doping of carbon nanotube films with chloroauric acid by dip-coating

Single-walled carbon nanotube (SWCNT) based transparent and conductive films (TCFs) are one of the most prospective materials for novel flexible and stretchable electronic devices. Development of reproducible and scalable doping procedure is the key step towards the widespread implementation of SWCNT TCFs. Here, we thoroughly investigate a dip-coating technique for SWCNT doping as a promising approach for the practical manufacturing of SWCNT films with high performance. We examine the effect of dip-coating parameters on optical and electrical properties of the films using HAuCl4 solution in isopropyl alcohol (IPA) and in situ investigate doping effects. This method appeared to easily fine-tune the optoelectronic parameters of SWCNT films and achieve a record sheet resistance value of 36 Ohm/sq. at the 90% transmittance in the middle of visible spectral range by increasing a work function value from 4.8 (for pristine SWCNTs) to 6.0 eV. The proposed approach allows efficient, uniform, and reproducible fabrication of highly conductive and transparent SWCNT films and opens an avenue for precise tailoring of SWCNT Fermi level for optoelectronic devices.

Solubility, solvation analysis and enthalpy–entropy compensation of musk ketone in some cosolvent solutions

The present work was mainly devoted to the solubility and modeling, intra- and inter-molecular interactions and solvation behavior for musk ketone dissolved in aqueous solutions of ethanol, N,N-dimethylformamide (DMF), methanol and isopropanol accompanied by various computational methodology. Solubility experiments were conducted by means of the common shake-flask technique under local pressure of p = 101.2 kPa at elevated temperatures from 278.15 to 318.15 K. For each aqueous cosolvent solution, the highest solubility magnitude of musk ketone appeared in neat cosolvent (ethanol, DMF, methanol or isopropanol) at T = 318.15 K; and the lowest one, in water at 278.15 K. The solubility behavior was studied by means of the Hansen solubility parameter. The mixture response surface model, Jouyban–Acree model, modified Wilson model and Jouyban–Acree–van’t Hoff model correlated satisfactorily the solubility magnitudes in mole fraction with relative average deviations of <4.15%. The relative contributions of solute–solvent and solvent–solvent molecular interactions to variation of musk ketone solubility at 298.15 K was quantitatively investigated through the linear solvation energy relationships, demonstrating that the dipolarity-polarizability along with solubility parameter of aqueous solvent systems were chiefly responsible for musk ketone solubility. The solvation performance was studied by an extended Hildebrand solubility approach applied to the solubility in four aqueous solutions and in ethyl acetate + methanol/isopropanol/ethanol solutions at 298.15 K, acquiring RAD of <4.05%. In addition, the preferential solvation of musk ketone was investigated quantitatively by means of the inverse Kirkwood–Buff integrals method in the four aqueous and three non-aqueous solutions. Musk ketone was preferentially solvated by ethanol/DMF/methanol/isopropanol (1) in aqueous solutions within middle and rich ethanol/DMF/methanol/isopropanol (1) compositions, and by ethyl acetate (1) in non-aqueous solutions within middle and rich ethyl acetate (1) compositions. Furthermore, the dissolution and transfer properties as well as enthalpy–entropy compensation were discussed in detail.

Nisoldipine in Several Aqueous and Non-Aqueous Cosolvent Solutions: Solubility Modeling and Preferential Solvation Research

The study mainly reported the equilibrated solubilities of nisoldipine in aqueous solutions of n-propanol/acetonitrile + water and non-aqueous solutions of ethyl acetate + ethanol/isopropanol by dint of experimentation and model correlations. Solubility was experimented via the shake-flask method under 101.2 kPa from 278.15 to 318.15 K. The maximum of nisoldipine solubility (in mole fraction unit) was found in neat n-propanol/acetonitrile/ethyl acetate at 318.15 K, and the minimum was found in neat water/isopropanol/ethanol. The total and three-dimensional Hansen solubility parameters were employed herein to explain the solubility behavior of nisoldipine. Modeling solubility through mixture response surface, Jouyban–Acree, and Jouyban–Acree–van’t Hoff models resulted in relative average deviations of <10.3%. Quantitative research upon preferential solvation was carried out by applying the approach of inverse Kirkwood–Buff integrals for the four solution systems considered in the present study and two aqueous solutions of ethanol/isopropanol reported in the literature. The local fractions of n-propanol/acetonitrile/ethanol/isopropanol for the four aqueous solutions as well as ethyl acetate for non-aqueous solution of ethyl acetate + isopropanol were greater than that of bulk ones in n-propanol/acetonitrile/ethanol/isopropanol/ethyl acetate-rich and middle composition proportions, demonstrating that the solvation of nisoldipine was preferred by cosolvents (n-propanol/acetonitrile/ethanol/isopropanol/ethyl acetate). It is able to speculate that nisoldipine displays Lewis acid behavior in these regions with the cosolvent molecules in aqueous solution systems and with the ethyl acetate molecules or isopropanol in the ethyl acetate + isopropanol solution system.

A Hierarchical Structure of Flower-Like Zinc Oxide and Poly(Vinyl Alcohol-co-Ethylene) Nanofiber Hybrid Membranes for High-Performance Air Filters.

In this article, we reported a hierarchical structure of flower-like zinc oxide (ZnO) and poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofiber (ZnO@NF) hybrid membranes for high-performance air filters. Monodispersed flower-like ZnO superstructures were fabricated using a template-free and surfactant-free hydrothermal method, and PVA-co-PE nanofiber yarns were prepared using a melt extrusion phase separation approach. The PVA-co-PE nanofiber yarns were subjected to high-speed shearing in a mixed aqueous solution of isopropanol and water to obtain a stably dispersed nanofiber suspension. The ZnO@NF hybrid air filter was obtained by coating the mixture of flower-like ZnO superstructures and the PVA-co-PE nanofiber suspension on the surface of the polypropylene (PP) meltblown nonwoven with the electret charge eliminated. The filtration efficiency of the ZnO@NF hybrid air filter increases with increasing loading amount of the flower-like ZnO superstructures, while the pressure drop decreases. The flower-like ZnO superstructures were incorporated into the nanofiber-interconnected networks, which significantly reduces the pressure drop of the pure PVA-co-PE nanofiber air filter. The filtration efficiency of the ZnO@NF hybrid air filter is much higher than that of PP meltblown nonwoven with eliminated electret charge, solving the hidden problem of electret charge dissipation during the protection process. It is demonstrated that these nanofiber hybrid air filters have great application potential in some special areas such as high-temperature and high-humidity environments.

MECHANICAL RECLAMATION OF WASTE SAND PRODUCED BY ADDITIVE MANUFACTURING PROCESSES

Metal casting manufacturers are increasingly adopting three-dimensional printing in their workflows as a way to remain competitive. Despite all the innovative development, strict environmental regulations and the intrinsic value of sand still make the recycling of waste sand an essential matter to consider when implementing the rapid sand-casting process. During the printing of the furan-bonded sand cores using binder jetting processes, waste sand is produced. This paper investigates the possibility of mechanically reclaiming the waste sand generated during the printing of sand cores. In this study, waste furan-bonded sand that was generated by three-dimensional printing using the Voxeljet VX 1000 printer was collected from the Vaal University of Technology. The collected waste sand was first characterised before being mechanically reclaimed using dry attrition, followed by dry screening and wet attrition, which involved washing the waste sand in a liquid solution of water and isopropyl alcohol. The results showed that mechanical reclamation using wet attrition is more effective in removing the residual binder in the sand than mechanical reclamation using dry attrition.

An experimental study on effect of titanium oxide coated heater substrate on pool boiling enhancement

The present experimental study indicates the effect of coating on the enhancement of heat transfer during pool boiling. For this, the aluminium heater substrate of 22 mm * 20 mm was coated with titanium oxide using high velocity oxy fuel (HVOF) method. The coated surface was then used to heat aqueous solutions of acetone, isopropanol, ethanol and distilled water respectively. Simultaneously, heat transfer coefficient (HTC) and excess temperature (dT) were also obtained using aluminium heater substrate without coating. The boiling parameters during coating and non-coating were kept same so that the HTC and dT obtained can be used for comparative study. The heat transfer parametric study was then conducted and the results were presented in graphical form.

Fully Automated Electrically Controlled Tunable Broadband Interferometric Dielectric Spectroscopy for Aqueous Solutions

A fully automated electrically controlled tunable interference-based microwave sensor is demonstrated with broadband complex permittivity measurements of aqueous solutions within the frequency range of 12–18 GHz. To construct deep destructive interference over the above-mentioned bandwidth, two quadrature hybrids (QHs or 90° coupler) split and combine the signals of material-under-test (MUT) channel and reference liquid (REF) channel with 180° phase shift. Together with voltage variable phase shifters (PSs) and attenuators in both channels, the destructive interference nulls of the desired frequency can be easily tuned having a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -factor of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.67\times {10}^{3}$ </tex-math></inline-formula> . A coplanar waveguide (CPW) sensor design was used as the microwave sensing structure and closed microfluidic channel was designed and manufactured with polydimethylsiloxane (PDMS) to facilitate the alteration of MUT, REF, and calibration liquids. Benefiting from electrically controlled PS and attenuator, the measurement system is fully automated for accurate and fast broadband microwave liquid characterization. Measurement of 2-propanol-water solutions (isopropyl alcohol (IPA) solutions) with volume concentration of 1% is performed to illustrate automation processes and its high sensitivity. A mathematical model improved from those in the literature by taking conductor loss and mismatch effects into consideration was applied to extract MUT permittivity, generalizing the calibration procedure with the air and deionized (DI) water as calibration materials, which results in improvements in accuracy, sensitivity, and effective MUT volume. Comparing to state-of-the-art sensors, the proposed setup has an average relative error (ARE) of 1.443% for the effective volume of 5.18 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{L}$ </tex-math></inline-formula> . The complex permittivity of 2-propanol-water solutions with different mole fractions were obtained and confirmed with current literature data.

Construction of MoS2 hybrid membranes on ceramic hollow fibers for efficient dehydration of isopropanol solution via pervaporation

Due to environmental issues and intense competition in the marketplace, industries and governmental organizations invest in new technology research to improve productivity, environmental protection, and cost-efficiency. Pervaporation is a membrane-based separation technology, which is cost-effective, environmentally friendly, and efficient in the separation of azeotropic mixtures. Here, we report the fabrication of a hybrid membrane based on molybdenum disulfide (MoS2) material, which can be used to dehydrate alcohol through a pervaporation process. Ceramic hollow fiber (CHF) membrane was used as a substrate in MoS2hybrid membrane, and TiO2 intermediate layer was constructed to reduce the macropores on the CHF surface. Polyethyleneimine (PEI) was used as a binder in the fabrication of the MoS2 layer. MoS2-PEI layer was prepared by vacuum suction method and then crosslinked with trimesoyl chloride (TMC) to prevent the hybrid layer from swelling in an aqueous solution. We investigated the morphology and physicochemical characteristics of the hybrid membranes by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and water contact angle (WCA) measurements. The fabricated MoS2hybrid membrane possesses a permeation flux of 5697 g m-2h−1 and separation factor of 320 in a 90 wt% isopropanol aqueous solution at 343 K. In this study, we provide a comprehensive understanding of the fabrication of MoS2hybrid membrane on the CHF membrane for efficient dehydration of isopropanol via the pervaporation process.

Controlled organosilica networks via metal doping for improved dehydration membranes with layered hybrid structures

• bis(triethoxysilyl)ethane (BTESE)-derived sols were doped with metal ions (Al and Zr) • Metal doped BTESE sols were coated on polymer support forming layered-hybrid structure. • Metal doped BTESE layered hybrid membranes improved PV dehydration performance. • Zr-BTESE showed water permeance > 10 -6 mol/(m 2 s Pa) with H 2 O/IPA > 10,000. A layered hybrid membrane consisting of an organosilica top layer on a polymeric nanoporous substrate was successfully fabricated using bis(triethoxysilyl)ethane (BTESE)-derived organosilica sols doped with metal ions (Al and Zr). These membranes were applied to the dehydration of aqueous alcohol solutions including methanol (MeOH), ethanol (EtOH) and isopropanol (IPA). Metal-doped BTESE sols and gels were characterized via dynamic light scattering analysis (DLS), Fourier Transform Infrared spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), the isotherms of N 2 sorption, laser scanning confocal microscopy (LSM), and scanning electron microscopy (SEM). During the dehydration of an IPA solution at 105 °C, the separation factors for Al-BTESE- and Zr-BTESE-derived membranes reached 8,000 and 10,000, respectively, which exceeded the separation factor for undoped BTESE membranes and indicates that doping with metal ions improves the dehydration performance of layered-hybrid membranes. In addition, Zr-BTESE-derived membranes prepared via the rinse method showed water permeance of 1.8 × 10 -6 mol m −2 s −1 Pa −1 , which is sufficiently high and compares favorably to that of polymer substrates. These membranes also showed a separation factor that was higher than 10,000. Correlations among the permeance ratios for H 2 O/MeOH, H 2 O/EtOH, and H 2 O/IPA were successfully predicted using modified gas translation (mGT) and bimodal pore models.