Double Solvent Research Articles

Enhanced compatibility and selectivity in mixed matrix membranes for propylene/propane separation

AbstractMixed matrix membranes (MMMs) based on metal–organic framework (MOF) have great promising application in separation of gas mixtures. However, achieving a good interfacial compatibility between polymer and MOF is not straightforward. In this work, focusing on one of the most challenging olefin/paraffin separations: propylene/propane (C3H6/C3H8), we demonstrate that modification of the MOF filler via dopamine polymerization using a double solvent approach strongly improves interfacial compatibility. The resulting membranes show an outstanding separation performance and long‐term stability with propylene permeability nearly 90 Barrer and propylene/propane selectivity close to 75. We anticipate that similar MOF modification strategies may help solve the problem of interface defects in the manufacture of MMMs and be extended to other porous fillers.

Effect of concentration of nickel precursor on the synthesis of Ni phyllosilicate for CO2 methanation: The promotion of supersaturation

In order to facilitate the synthesis of nickel phyllosilicate through hydrothermal method, the effect of different concentration of Ni(NO3)2 aqueous solutions on nickel phyllosilicate synthesis was investigated in this work. It was found that Ni-phyllosilicate could hardly been formed at the low concentration of the Ni(NO3)2 aqueous solution (0.05 mol･L−1), and a small amount of Ni-phyllosilicate was formed when the concentration increased to 0.10 mol･L−1. The double solvent system of H2O and cyclohexane could further enhance the formation of Ni-phyllosilicate due to the promotion of supersaturation. Furthermore, the N/M-D-A-120 catalyst prepared in the presence of double solvent and the accelerators of NH4F and urea exhibited high Ni content and small Ni crystal size, leading to the high catalytic activity and long-term stability for CO2 methanation. In short, the concentration of Ni(NO3)2 aqueous solution was an important factor for the efficient formation of Ni-phyllosilicate, and the construction of double solvent of H2O and cyclohexane could further increase the supersaturation and enhance the Ni-phyllosilicate synthesis.

Synergistic effect of double solvent and accelerator on efficient synthesis of nickel phyllosilicate for CO2 methanation

In order to facilitate the synthesis of nickel phyllosilicate through the hydrothermal method, different process parameters including high or low hydrothermal temperature, single or double solvent, and with or without accelerator were investigated in this work. The Ni/DA-150-6 catalyst prepared in the presence of double solvent and the accelerator exhibited high Ni content, small Ni crystal size, and large H2 and CO2 chemisorption capacity, leading to the highest catalytic activity for CO2 methanation. Meanwhile, Ni/S-200-12 synthesized by the high-temperature (200 °C) hydrothermal method or Ni/D-150-12 prepared at 150 °C in the presence of double solvent displayed low catalytic activity owing to the low Ni content. In short, the synergistic effect of double solvent and accelerator is the most significant strategy for the efficient synthesis of Ni-phyllosilicate.

Removal of persistent acetophenone from industrial waste-water via bismuth ferrite nanostructures.

Increasing water pollution is a severe problem in densely industrialized countries. Nanomaterials provide strong potentials for the efficient elimination of organic pollutants due to their beneficial properties. Advancement in water purification is required to more efficiently remove the emerging organic contaminants, especially in pharmaceuticals wastes such as acetophenone, which shows high solubility in industrial wastewaters. Bismuth ferrite-based nanostructures were fabricated using a novel double solvent sol-gel method. The phase purity and crystallinity of bismuth ferrite were confirmed using XRD and further endorsed by TEM analysis. The SEM and XPS were used to study the particle sizes and presence of co-dopants on the Bi and Fe-sites of bismuth ferrite. After co-doping, the band-gap engineering of pure bismuth ferrites was accomplished by reducing it from 2.06eV to 1.45eV, likely attributing to the creation of shallow traps for the incoming photo-generated charge carriers. In particular, the Bi0.90Gd0.10Fe0.95Sn0.05 and Bi0.95Sm0.05Fe0.75Mn0.25 successfully eliminated up to 98% of acetophenone from polluted water in 3h by irradiation of visible-light. These results reveal the suitability of the co-doped bismuth ferrites photocatalysts for the practical removal of pharmaceutical contaminants in hazardous industrial wastewater. The photodegradation of acetophenone by bismuth ferrite nanostructures with potentially long-lasting reusability demonstrate its potential as an advanced photocatalyst for wastewater treatment.

Optimization of operating conditions for anisole hydrodeoxygenation reaction over Zr-based metal–organic framework supported Pt catalyst

To optimize the operating conditions for catalytic hydrodeoxygenation (HDO) of anisole in a continuous fixed-bed reactor, the response surface methodology combined with the central composite design was used to maximize the conversion by tuning the molar ratio of H2 to anisole, temperature, and pressure, which are considered key parameters on catalytic reaction. Analysis of variance was used to determine the regression model's compatibility. The catalyst was prepared using a Zr-based metal–organic framework, UiO-67, as a support, which was synthesized under microwave-assisted solvothermal reaction, followed by loading Pt nanoparticles on its surface via a double solvent method. The results demonstrated that the obtained mathematical model accurately predicted the conversion, which was more greatly influenced by temperature in comparison with the H2/anisole molar ratio and pressure in HDO reaction over the 3 wt% Pt/UiO-67 catalyst. Concurrently, the highest conversion of 92.5% was obtained under the optimum conditions: H2/anisole molar ratio of 35.2, reaction temperature of 297.6 °C, and a reaction pressure of 12.8 bar. The relative error was only 1.08% when compared with experimental values obtained under near-optimum conditions. Furthermore, at high temperatures, the reaction pathway followed the demethoxylation trend, yielding cyclohexane and benzene as the main products.

The Evaluation of Bone Regeneration Following Socket Preservation with Concentrated Growth Factor (CGF) and Poly Lactic-Co-Glycolic Acid (PLGA) Scaffold in Rabbits

Various grafting materials are utilised to facilitate regeneration. There is currently a paradigm shift towards applying poly lactic-co-glycolic acid (PLGA), which is regarded as an excellent scaffold for tissue engineering. Concentrated growth factor (CGF) has also been reported to promote wound healing. Nevertheless, the role of PLGA microspheres as a substitute for bone graft material with CGF in bone regeneration remains unclear. This study was designed to evaluate the effect of CGF with PLGA on bone formation and the expression of alkaline phosphatase (ALP) following socket preservation. PLGA microspheres were prepared using double solvent evaporation method and observed under scanning electron microscopy (SEM). A 6 mL of rabbit’s blood was collected from the marginal ear vein and centrifuged to obtain CGF. Blood was also collected for ALP assessment from 24 New Zealand White (NZW) male rabbits subjected to the first upper left premolar extraction. Sockets were filled with CGF, PLGA, CGF+PLGA or left empty and observed with microscopic computed tomography (micro-CT) at four weeks and eight weeks. The SEM image revealed a spherical shape with interconnected pores on the surface of the PLGA particles. Repeated measures ANOVA were used to evaluate the effect of time and treatment (p < 0.05) with significant differences in bone width, height, volume, volume fraction and expression of ALP was observed with CGF+PLGA. Both CGF and PLGA have the potential as the alternative grafting materials and this study could serve as an ideal benchmark for future investigations on the role of CGF+PLGA in bone regeneration enhancement.

Screening of Double Solvents Based on Multi-Index Evaluation Method for the Selective Separation m-Cresol from Model Oil.

Ionic liquid (IL) as an extractant is an effective method for separating oil–phenol mixtures. However, relatively high neutral oil entrainment can lead to oil loss and a remarkable reduction in phenol purity. To reduce the entrainment of neutral oil in the extraction process, a double-solvent extraction system composed of IL 1-ethyl-3-methyl imidazolium acetate ([C2mim][Ac]) and an organic solvent was investigated. The multi-index evaluation method was used to screen the conventional organic solvent. The double-solvent extraction experiments were employed to verify the accuracy of the COSMO-RS prediction. Eighteen organic solvents, the interaction energy with m-cresol and cumene (neutral oil), their extraction ability, and mutual solubility with [C2mim][Ac], were calculated by COSMO-RS. Alkane and cycloalkane were screened due to their strong interaction and low distribution coefficient with cumene, as well as the low mutual solubility with [C2mim][Ac]. The experimental results were in good agreement with the COSMO-RS prediction, and cyclopentane as an organic solvent had the lowest distribution coefficient and entrainment of cumene because of its strong nonpolarity and hydrogen-bond repulsive interaction, which was explained by the σ-profile and σ-potential analysis. When the cyclopentane-to-[C2mim][Ac] mass ratio increased from 0.0 to 3.0, the entrainment of cumene was evidently declined from 39.5 to 5.8% and the selectivity to m-cresol was improved from 378.0 to 1058.5.

Dried Blood Spots as Matrix for Evaluation of Valproate Levels and the Immediate and Delayed Metabolomic Changes Induced by Single Valproate Dose Treatment

The immediate and delayed metabolic changes in rats treated with valproate (VPA), a drug used for the treatment of epilepsy, were profiled. An established approach using dried blood spots (DBS) as sample matrices for gas chromatography/mass spectrometry-based metabolomics profiling was modified using double solvents in the extraction of analytes. With the modified method, some of the previously undetectable metabolites were recovered and subtle differences in the metabolic changes upon exposure to a single dose of VPA between males and female rats were identified. In male rats, changes in 2-hydroxybutyric acid, pipecolic acid, tetratriacontane and stearic acid were found between the control and treatment groups at various time points from 2.5 h up to 24 h. In contrast, such differences were not observed in female rats, which could be caused by the vast inter-individual variations in metabolite levels within the female group. Based on the measured DBS drug concentrations, clearance and apparent volume of distribution of VPA were estimated and the values were found to be comparable to those estimated previously from full blood drug concentrations. The current study indicated that DBS is a powerful tool to monitor drug levels and metabolic changes in response to drug treatment.

PH-Responsive Regulation of a Surfactant-Free Microemulsion Based on Hydrophobic Deep Eutectic Solvents.

Microemulsions containing a responsive hydrophobic deep eutectic solvent (HDES) as the oil phase that can replace conventional organic solvents are considered to be a green strategy. It is anticipated that a pH-responsive HDES is synthesized to prepare rapid responsive surfactant-free microemulsions (SFMEs), which enable the transition from SFMEs to nanoemulsions. Menthol and n-octanoic acid (OA) were assembled into HDES by hydrogen bonding at a molar ratio of 1:2. The pH-responsive HDES as the oil phase and isopropyl alcohol (IPA) as the double solvent could form HDES/IPA/water SFMEs, which have unique responsiveness. Specifically, from the nuclear magnetic resonance hydrogen spectrum, pH, thermogravimetry, and Fourier transform infrared spectroscopy investigations, the excellent switchability and stability of menthol-OA were demonstrated. On the basis of these complexes, microemulsions were successfully prepared. Electrical conductivity and pH measurements were used to determine the structures of microemulsions and the phase inversion process. The effects of the contents of water and HDES, NaCl concentration, and pH of the system were investigated. Nanoemulsions were successfully prepared on the basis of the pH response of the microemulsions. In addition, the prepared nanoemulsion has a unique pH-responsive behavior that can be controllably regulated among nanoemulsions, microemulsions, and phase separation systems.

Morphology manipulation of NaYbF4:Er3+ nano/microstructures by hydrothermal synthesis and enhanced upconversion red emission for bioimaging

The synthesis of NaYbF4 crystals was successfully accomplished by a facile hydrothermal method. The phase and the morphology of the products were governed by reaction times, tuning the PH values and double solvents co-doping. The products with diverse morphologies, including quasi-spherical nanoparticles, hollow microtubes, microrods, nanorods, flower-like microprisms, and branch-like irregular shapes, were prepared under different external parameters. The experimental results demonstrate that the reaction time, PH value and organic additives play vital roles in the phase and morphology of the products. Photoluminescence measurements demonstrate that the relative upconversion (UC) photoluminescence intensity of as-prepared products strongly depends on the crystal phase, morphology, size, crystallinity, surface organic group, as well as surface defects. Impressively, the energy transfer mechanisms are systematically clarified, and the enhancement of red emission is ascribed to the high Yb3+ concentration. The emission colors might be finely tuned from green to orange-red. Furthermore, the luminescence decay lifetime is related to morphologies, sizes, defects, emission intensity, and Red/Green (R/G) ratio. Particularly, through simple cytotoxicity test and in vivo bioimaging, the synthesized UC red emission nanospheres have broad application prospects in the field of biochemistry.

Medicinal Potential of Ocimum Gratissimum (Scent Leaf) and Vernonia Amygdalina Del (Bitter Leaf)

Fruits and vegetables are a great source of phytochemicals that play protective roles in many diseases. A comparative phytochemical composition of Ocimum Gratissimum L. (Scent leaf) and Vernonia Amygdalina Del (Bitter leaf) was carried out. The plant samples were washed thoroughly and sun dried till no moisture was felt and then each sample was blended into fine powder and stored in air tight container for analysis. The blended sample was placed in a soxhlet extractor. This was done differently for each of the test samples, using a thimble. The extraction was done using 250ml of ethanol for about four hours. After the extraction, the solvent used (ethanol) was recovered from the crude extract and the extract concentrated by distillation. Quantitative determination of flavonoid was done according to the method described by Harbone (1973). Saponin content of the sample was determined by double solvent extraction gravimetric method as described by Harbone (1973). The quantitative determination of alkaloid was carried out by alkaline precipitation, through gravimetric method described by Harbone (1973). Phenol content of sample was determined by the method described by Pearson (1976). The fallins-Denis spectrophotometric method as described by Harbone (1973) was used for the determination of tannin. The study revealed that Veronia Amygdalina yielded higher alkaloid, flavonoid and saponin (22.5%, 12% and 7.85% respectively) than Ocimum Gratissimum which yielded (alkaloid 7.5%, flavonoid 10%, and saponin 4.05%). On the contrary Ocimum Gratissimum had a higher yield of tannin and phenol (0.514% and 0.445% respectively) against Vernonia Amygdalina tannin 0.4145 and phenol 0.400%. These values showed that Ocimum Gratissimum protects more against bacterial, fungal and microbial infections compared to vernonia Amygdalina. Similarly, vernonia Amygdalina contains more antioxidant and hypolipidemic\hypocholesterolemic properties, than Ocimum Gratissimum hence could prevent diseases caused by oxidative stress, inhibit heart attack, cancerous cell growth and proliferation and is not likely to contribute to any disease associated with hyperlipidemia compared to Ocimum Gratissimum.

Effect of Co-Doping on Thermoelectric Properties of n-Type Bi2Te3 Nanostructures Fabricated Using a Low-Temperature Sol-Gel Method.

In this work, a novel low-temperature double solvent sol-gel method was used to fabricate (Sm, Ce, Gd) and (Sn, Se, I) co-doped at Bi and Te-sites, respectively, for Bi2Te3 nanostructures. The phase-purity and high crystallinity of as-synthesized nanostructures were confirmed using X-ray diffraction and high-resolution transmission electron microscopy. The nanopowders were hot-pressed by spark plasma sintering into bulk pellets for thermoelectric properties. The spark plasma sintering temperature significantly affects the Seebeck coefficient and electrical conductivity of bulk Bi2Te3 pellets. The electrical conductivities of co-doped samples decrease with an increase in the temperature, but conversely, the Seebeck coefficient is linearly increasing. The power factor showed that the co-dopants enhanced the thermoelectric properties of Bi2Te3 nanopowders.

Design, preparation and evaluation of nanoparticles of 5-Flurouracil for the targeted delivery to treat colon cancer

The objective of the study is to prepare the nano particles of 5-fluorouracil with targeted delivery to the colon with enhancement of bioavailability and decrease the side effects of the drug. 5-Fluorouracil-loaded PLGA nanoparticles were developed by double solvent evaporation technique method. Characterization was carried out by determination of encapsulation efficiency (%), loss on Drying. The in-vitro drug release of drug 5- Fluorouracil was carried out for formulations (F1-F4), it is concluded that F4 was the best formulation which shows the most desired rate drug release and concluded that the polymer PLGA have a capacity of protection the drug in the GI and small intestinal Fluid hence, the maximum release of drug in the colonic region of large intestine.

Ultrafine PdRu Nanoparticles Immobilized in Metal–Organic Frameworks for Efficient Fluorophenol Hydrodefluorination under Mild Aqueous Conditions

Ultrafine PdRu Nanoparticles Immobilized in Metal–Organic Frameworks for Efficient Fluorophenol Hydrodefluorination under Mild Aqueous Conditions

Gellan Gum-Based Bilayer Mucoadhesive Films Loaded with Moxifloxacin Hydrochloride and Clove Oil for Possible Treatment of Periodontitis.

Background/ObjectivePeriodontitis is a widely spread oral infection and various antibiotics are utilized for its treatment, but high oral doses and development of antibiotic resistance limit their use. This study was aimed at development of natural polymer-based mucoadhesive bilayer films loaded with moxifloxacin hydrochloride (Mox) and clove essential oil (CEO) to potentially combat bacterial infection associated with periodontitis.MethodsFilms were synthesized by double solvent casting technique having an antibiotic in the gellan gum-based primary layer with clove oil in a hydroxyethyl cellulose-based secondary layer.ResultsPrepared films were transparent, flexible, and showed high antibacterial response against both gram-positive and gram-negative bacteria. The films showed excellent pharmaceutical attributes in terms of drug content, folding endurance, swelling index, and mucoadhesive strength. Solid state characterization of formulation showed successful incorporation of drug and oil in separate layers of hydrogel structure. An in-vitro release study showed an initial burst release of drug followed by sustained release for up to 48 hours.ConclusionThe prepared mucoadhesive bilayer buccal films could be used as a potential therapeutic option for the management of periodontitis.

Double-solvent-assisted synthesis of bimetallic CuFe-incorporated MIL-101(Cr) for improved CO-adsorption performance and oxygen-resistant stability

In this study, a bimetallic CuFe-incorporated MIL-101(Cr) adsorbent was developed with enhanced CO-adsorption capacity and oxygen resistance. Different compositions of bimetallic Cu(II)–Fe(II) were incorporated into the MIL-101(Cr) framework with ultrahigh porosity by the double-solvent (DS) method, followed by facile reduction at a low temperature of 250 °C. By employing formate (HCOO−), Cu(II) was selectively reduced to Cu(I) at 250 °C. Moreover, the presence of the reducing agent, Fe(II), enhanced the reduction of Cu(II) in the adsorbent. The obtained results indicated that the synergistic effect of utilizing Fe(II) and employing the DS method significantly enhanced the dispersion of the formed Cu(I) in the support. The DS-assisted CuFe (4 mmol g−1 of CuCl and 1.0 mmol g−1 FeCl2)-incorporated MIL-100(Fe) adsorbent exhibited a high CO-adsorption capacity of ca. 3.24 mmol g−1 and CO/N2 selectivity of 428 at 25 °C and 100 kPa, which were superior to those of the counterpart that was prepared by the wetness impregnation method. Additionally, the CO-adsorption capacity of the prepared CuFe-incorporated MIL-100(Fe) was still 90–65% after it was exposed to atmospheric humidity for 15–30 days, thereby demonstrating its superior oxygen-resistant stability compared to those of the benchmark π-complexation adsorbents containing Cu(I).

High Quality Bio-Oil Obtained from Catalyzed Pyrolysis of Olive Mill Solid Wastes in a Bi-Functional Reactor

Olive Mill Solid Wastes (OMSW) released in nature without any treatment is a major environmental problem in the Mediterranean region. In this work, the catalyzed pyrolysis of OMSW has been investigated. A catalyst based on SBA-15 mesoporous silica doped with chromium ferrite nanoparticles was prepared by the double solvent technique (DS). The prepared catalyst was characterized by scanning electron microscopy (SEM), Wide and Small Angle X-ray Scattering (WAXS, SAXS), Energy Dispersive X-ray (EDX) and FT-IR spectroscopies. Reverse spinel chromium ferrite nanoparticles were located inside the SBA-15 pores as confirmed by SEM images. The obtained catalyst was tested for pyrolysis reactions of OMSW. Several parameters were studied to optimize the conditions of the pyrolysis reaction in order to increase the bio-oil conversion yield. The GC-MS results demonstrated that the quality of the obtained bio-oil was improved by decreasing the quantity of phenolic and oxygenated components as well as the size of the obtained molecules. The produced bio-oil from pyrolysis of OMSW is identical to that obtained from the pyrolysis of commercial cellulose under the same conditions. A 37% conversion yield of bio-oil was obtained for the best conditions.

Cu/ZnOx@UiO-66 synthesized from a double solvent method as an efficient catalyst for CO2 hydrogenation to methanol

The Cu precursor diffused into UiO-66 by the double solvent method is reduced by NaBH4 to form Cu nanoparticles. After introducing Zn2+, Cu/ZnOx@UiO-66 reduced by H2 is synthesized, which catalyzes the hydrogenation of CO2 to methanol efficiently.

Bimetallic AgPd/UiO-66 Hybrid Catalysts for Propylene Glycol Oxidation into Lactic Acid.

Different methods (the wetness impregnation of Ag and Pd precursors dissolved in water or acetonitrile solution, and the double solvent impregnation technique) were employed to immobilize Ag–Pd nanoparticles (NPs) into the pores of the microporous zirconium-based metal-organic framework known as UiO-66. The obtained materials were characterized by using nitrogen adsorption-desorption at −196 °C, powder X-ray diffraction, UV-Vis diffusion reflectance spectroscopy, and transition electron microscopy measurements. Special attention was paid to the acid and redox properties of the obtained materials, which were studied by using temperature-programmed desorption of ammonia (TPD-NH3) and temperature-programmed reduction (TPR-H2) methods. The use of a drying procedure prior to reduction was found to result in metallic NPs which, most likely, formed on the external surface and were larger than corresponding voids of the metal-organic framework. The formation of Ag–Pd alloy or monometallic Ag and Pd depended on the nature of both metal precursors and the impregnation solvent used. Catalytic activity of the AgPd/UiO-66 materials in propylene glycol oxidation was found to be a result of synergistic interaction between the components in AgPd alloyed NPs immobilized in the pore space and on the external surface of UiO-66. The key factor for consistent transformation of propylene glycol into lactic acid was the proximity between redox and acid-base species.

Preparation and characterization of composite adsorbent LiCl/zeolite 13X for adsorption system

A novel composite adsorbent with high adsorption capacity, stable cycle performance and structure is developed. LiCl/zeolite 13X composite adsorbents with different LiCl content were synthesized by double solvents impregnation with alcohol and ethanol. The textural properties of composite adsorbents were characterized by nitrogen adsorption and scanning electron microscopy (SEM). The water adsorption performance of the composite adsorbents was tested, and the dynamic and equilibrium adsorption characteristics of the composite adsorbents were simulated by Polanyi potential theory and LDF model, respectively. Research on nitrogen adsorption suggested that because of the impregnated salt, composite adsorbents presented different pore structure pure. As the salt concentration of the LiCl solution increases, more salt is immersed into the pore channels of zeolite 13X, resulting in the LiCl content in the adsorbents increasing simultaneously. Water adsorption capacity of the composite adsorbent is not enhanced consistently with the increase in LiCl loading amount. After LiCl modification process, the water adsorption capacity increases little when the salt load is low, and then, the water adsorption capacity increases significantly with the increase in the salt load and finally decreases slightly. The sorption performance of CS30 with salt content of 16.7 wt% was optimal, and the maximum sorption capacity was 0.7 g/g, nearly 3.3 times than properties of zeolite 13X 0.21 g/g. As the number of cycles increases, the adsorption capacity of the composite adsorbent decreases slightly. The tenth cycle is only reduced by 8.67% compared to the first cycle.