Liquid-phase Media Research Articles

Effect and optimization parameters of phenol removal in emulsion liquid membrane process via fractional-factorial design

Phenol removal from wastewater was investigated and optimized using formulated blended surfactant ionic liquid emulsion liquid membrane. In this research, a mixture of kerosene and palm oil was chosen as a liquid membrane phase medium. The components utilized in the emulsion formulation are palm oil to kerosene (7:3 ratio) as diluent, blended surfactant of Span 80 and Tween 80 as surfactants, ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM]+[NTf2]−) as a stabilizer, and sodium hydroxide (NaOH) as a stripping agent. The experimental of extraction process was designed and optimized using fractional-factorial design and response surface methodology (RSM) respectively. In this study, the optimum process conditions were obtained at an agitation speed of 267 rpm, 5 min of extraction time, 0.107% (w/v) of the concentration of ionic liquid and treat ratio of 1:7.3 where 83% of phenol was extracted in stable duration process without emulsion breakage. Meanwhile, about 11 times enrichment ratio of phenol was recovered as concentrated phenolate solution in the stripping phase. In conclusion, emulsion stability, phenol extraction and recovery could be increased using blended surfactant ionic liquid.

Experimental Studies of Process of Hydrogen Synthesis in Plasma Discharge in a Liquid-Phase Stream

In this work, experimental studies of the process of obtaining hydrogen in a plasma discharge initiated in a liquid stream of different chemical composition were carried out. A two-phase flow was created when a liquid medium under high pressure passed through a hydrodynamic irradiator. A supersonic two-phase vapor-liquid flow under reduced pressure is formed in the fluid due to the pressure drop and decrease in the enthalpy of the flow. The plasma discharge was initiated by an external power source, which creates an electric field inside the reaction chamber. Several shapes and sizes of reaction chambers with different electrode arrangements were tested. Pure water as well as alcohols, esters, and their mixtures with water were used as starting liquids. As a result of experimental studies, it was shown that a low-temperature plasma initiated under the conditions of a flow of a liquid-phase medium in the discharge gap between the electrodes can effectively decompose hydrogen-containing molecules of organic compounds in a liquid to form gaseous products with a significant proportion of hydrogen. It is shown that the highest efficiency of the process is when using mixtures of alcohols and water as a raw material. This opens the possibility of using this process in the processing of crude ethanol and other products of the fermentation of cheap plant materials. The decomposition of organic compounds in plasma also produces insignificant amounts of carbon nanoparticles and oxide nanoparticles of discharge electrode materials.

SYNTHESIS OF HYDROGEN IN ACOUSTOPLASMA DISCHARGE IN A LIQUID-PHASE STREAM

In this paper, the plasma discharge in a high-pressure fluid stream in order to produce gaseous hydrogen was studied. Methods and equipment have been developed for the excitation of a plasma discharge in a stream of liquid medium. The fluid flow under excessive pressure is directed to a hydrodynamic emitter located at the reactor inlet where a supersonic two-phase vapor-liquid flow under reduced pressure is formed in the liquid due to the pressure drop and decrease in the flow enthalpy. Electrodes are located in the reactor where an electric field is created using an external power source (the strength of the field exceeds the breakdown threshold of this two-phase medium) leading to theinitiation of a low-temperature glow quasi-stationary plasma discharge.A theoretical estimation of the parameters of this type of discharge has been carried out. It is shown that the lowtemperature plasma initiated under the flow conditions of a liquid-phase medium in the discharge gap between the electrodes can effectively decompose the hydrogen-containing molecules of organic compounds in a liquid with the formation of gaseous products where the content of hydrogen is more than 90%. In the process simulation, theoretical calculations of the voltage and discharge current were also made which are in good agreement with the experimental data. The reaction unit used in the experiments was of a volume of 50 ml and reaction capacity appeared to be about 1.5 liters of hydrogen per minute when using a mixture of oxygen-containing organic compounds as a raw material. During their decomposition in plasma, solid-phase products are also formed in insignificant amounts: carbon nanoparticles and oxide nanoparticles of discharge electrode materials.

Evaluation of microbial proliferation on cementitious materials exposed to biogas systems

ABSTRACT Understanding the interactions between biofilm and cementitious materials in biogas production systems is an essential step toward the development of durable concrete for this expanding sector. Although the action of the liquid phase medium on the material has been the subject of several research studies, the possible impact of the material’s properties on biofilm formation and composition has been little investigated, if at all. The aim of this paper is to evaluate the characteristics of the biofilm according to the surface properties of the materials. Four cementitious materials with different chemical and mineralogical compositions, and various topological surface characteristics (pastes of CEM I, CEM III/C and CAC, and CEM I paste treated with oxalic acid) were exposed to the liquid phase of a fermenting biowaste for 10 weeks. The steps of biofilm formation were observed using SEM. Even though all the cementitious material surfaces were intensely colonized at the end of the experiments, the establishment of the biofilm seems to have been delayed on the oxalate-treated CEM I and on CAC coupons. Roughness and surface pH effects were not of prime importance for the biofilm development. The analysis of bacterial population diversity using 16S rDNA sequencing showed a less diversified microbial flora in the biofilm than in the reaction medium.

Plasma Discharge in Liquid Phase Media under Ultrasonic Cavitation as a Technique for Synthesizing Gaseous Hydrogen

It is shown that low-temperature plasma initiated in liquid-phase media in the discharge gap between electrodes can efficiently decompose hydrogen-containing molecules of organic compounds with the formation of gaseous products in which the hydrogen fraction is more than 90% (according to gas chromatography data). Preliminary estimations of the energy efficiency calculated taking into account the hydrogen and source material combustion heat and electric power expenditures showed the efficiency of the order of 60–70% depending on the source mixture composition. The discharge voltage and current were theoretically calculated in the process simulation whose data are in agreement with experimental results.

Amine functionalized AFI type microporous SAPO-5 materials: preparation, unique method on template extraction, characterization and its catalytic application on epoxide ring opening

Microporous AFI type silicoaluminophosphate (SAPO-5) having aminosilane functionality in the framework was prepared by in-situ (direct co-condensation) approach under hydrothermal conditions. The template (structure directing agent) presents within the channels of synthesized aminosilane modified SAPO-5 framework was selectively removed by a unique method using acidic ethanol extraction. Before and after the template extraction, presence of AFI type phase of SAPO-5 was confirmed through powder XRD pattern. The complete removal of template from the channels of framework was confirmed through FT-IR, 13C MAS NMR and N2 sorption studies. The covalent bonding of aminosilane functionality within the organic–inorganic hybrid SAPO-5 framework was evident through 29Si MAS NMR and 13C MAS NMR studies. The final material was utilized for selective synthesis of 1-phenoxy-2-propanol (99%) via propylene oxide ring opening with phenol under solvent free conditions in liquid phase medium.

Preparation of cyclic carbonate via cycloaddition of CO2 on epoxide using amine-functionalized SAPO-34 as catalyst

Amine-functionalized chabazite (CHA) type silicoaluminophosphate (SAPO-34) materials were prepared under hydrothermal conditions by a direct co-condensation method. Different concentrations of an organo-amine (3-aminopropyltrimethoxysilane) were incorporated into the CHA-type framework under hydrothermal conditions. The crystalline structures of the organoamine modified SAPO-34 materials with different concentrations of amine functionalities were confirmed by powder XRD. The morphology of the materials was confirmed by SEM, FE-SEM, and TEM analysis. The successful incorporation of amine-functionalities into the wall of SAPO-34 framework was confirmed by 29Si and 13C magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The acidity and basicity of the materials was studied by NH3 and CO2 temperature programmed desorption (TPD). The resultant amine-functionalized SAPO-34 materials were utilized for the cyclo-addition of CO2 to epoxide in liquid phase medium. The organoamine-modified SAPO-34 acted as a bi-functional (acidic and basic) catalyst. The incorporated amine sites played a crucial role in CO2 activation on the surface, while the acidic sites of the SAPO-34 framework accelerated the epoxide ring opening. Thus, the amine-functionalized SAPO-34 prepared as described in this work can be an effective catalyst for the activation and utilization of CO2 in cyclic carbonate synthesis from epoxides (98%) conversion of epichlorohydrin with 96% selectivity toward cyclic carbonate.

Production testing of refractometric device for control over liquid-phase media

Production testing of refractometric device for control over liquid-phase media

Laser beam-induced bistability of concentration in nanofluids

We conduct a theoretical study ofthe dynamics of the concentration of nanoparticles in liquid-phase media under the influence of a laser light field. An exact solution of the nonlinear diffusion equation in the form of switching wavesis found. It is shown that, in the conditions of a fixed temperature and a nonlinear medium thermal conductivity, nanofluid becomes bistable.

The brandon method in modelling the cavitation processing of aqueous media

A 4-factor multiplicative mathematical model was built in order to find the best mode of cavitation processing of aqueous media, in which the value of heat energy released during cavitation is maximal. The model links the heat energy value with technological (inlet pressure in the cavitator) and design (nozzle diametre, the number of nozzles, the angle of attack jets) parametres. The adequacy of the derived regression equation is confirmed by the Fisher criterion (F<F T =0.203<1.51). The accuracy of the model has been assessed by the coefficient of determination and the mean relative error of approximation (e MRE =5.85 %). The analysis of the 4-factor multiplicative model allowed finding the optimal conditions for cavitation processing of liquid-phase media; they are as follows: inlet pressure – 0.54–0.6 MPa, nozzle diametre – 1.6 mm, the number of nozzles – 4–5, and the angle of attack jets – 144–170 degrees. It is found that, in comparison with the absence of air, the content of air of 2±0.25 % by the volume of an aqueous medium greatly intensifies the formation of the “flotation” layer (its height, dispersibility of bubbles, and gas saturation). The derived multifunctional dependence allows controlling the effectiveness of cavitation processing of aqueous media by means of changing the design parametres of cavitating parts.

Optical properties of carbamide aqueous solutions

Subject of Research. The paper presents the results of measurements of refractometric properties (refractive index n, its temperature factor dn / dt ) and the ultraviolet spectral absorption in carbonic acid diamide aqueous solutions (carbamide) depending on solid residue mass fraction m d = 0-50 % and on temperature t = 10-70 °C. Method of Research. Laboratory methods of liquid-phase medium refractometry and ultraviolet spectrophotometry were applied for the research. We carried out computational modeling of electronic states spectrum for the carbonic acid diamide molecule and theoretical calculation of the fundamental electronic absorption of the molecule in the ultraviolet wavelenght region. Main Results. We have established that the solution concentration m d has a nonlinear character and may be represented by the quadratic polynomial with the error Δ n = ± 0,0005. We have shown the refractive index dependence on temperature n ( t ) changes in linear fashion at t = 10-70 °C. At that, the inclination of lines n ( t ) increases at the increase of m d; so, the temperature factor dn / dt may be approximated by the quadratic polynomial. Transmission spectra of solutions in the spectral region λ = 225-760 nm have no special features except for the sharp edge in the short-wavelength region; the fundamental electronic absorption is responsible for it. We have established that dispersion dependences of the refraction index n (λ; m d) in aqueous solutions of carbamide at λ = 360-760 nm and at m d = 0-50 % may be calculated with the satisfactory error without additional adjustable parameters from the ultraviolet absorption data in terms of the one-dimentional oscillator Lorentz model. Practical Relevance. Represented measurements of carbonic acid diamide aqueous solutions optical properties may be applied for the adjustment and calibration of commercial refractometers at processing lines of the AdBlue reagent manufacture for the selective catalytic reduction (SCR) of motor transport exhaust gases.

Biotransformation of β-Artemether by Aspergillus niger and Aspergillus flavus, and Antifungal Activity of Their Metabolites

β-Artemether (1) on fermentation with Aspergillus niger and Aspergillus flavus by liquid-phase medium yielded β-artemetherfurano acetate (2) and 3α-hydroxydeoxy-β-artemether (3), whereas with Aspergillus niger by solid-phase medium yielded β-artemetherfurano acetate (2) and deoxydihydroartemisinin (mixture of α and β isomers) (4 and 5). Their structures were elucidated by modern spectroscopic methods and reported data. β-Artemether (1) and both of its biotransformed products 2 and 3 were screened for their antifungal activity using the agar-well method.

Synthesis of 3,5-dimethyl-1-prop-2-enylpyrazole under solid–liquid phase transfer catalytic conditions assisted by ultrasonic irradiation—A kinetic study

The synthesis of 3,5-dimethyl-1-prop-2-enylpyrazole was successfully carried out by reacting the 3,5-di-methyl pyrazole with 3-bromoprop-1-ene in small amount of KOH and organic solvent solid–liquid phase medium under phase transfer catalysis (PTC) and almost anhydrous conditions assisted by the ultrasonic irradiation in the 5h at 50°C. The main target of this carried work was to provide evidence that the reaction conditions by investigation of the kinetic behaviour, activation energy, reaction mechanism and the related parameters in the solid–liquid PTC reaction besides on to reduce time and temperature of reaction. A rational mechanism for the reaction has been derived base on the experimental result. This kinetic reaction follows pseudo first order rate law. A rate expression had developed to explain the kinetic behaviours from which the apparent rate constant (kapp) of the organic-phase reaction was obtained via investigated data. Kinetics of the reaction, including the effects of agitation speed, quantity of potassium hydroxide, quantity of water, temperature, quantity of tetraoctylammonium bromide (TOAB), volume of cyclohexanone, quarternary ammonium salts and organic solvents on the conversion of RBr and the apparent rate constant (kapp) were investigated in full length. Rational explanations for the resulting phenomena are also provided.

Zinc-Modified MCM-22 as Potential Solid acid Catalyst for Friedel–Crafts Alkylation Reaction

Abstract In this paper, we report loading of ZnCl2 on microporous medium pore high surface area zeolite, which was achieved by incipient wetness method. The zinc-modified mobil composite material -22 (Zn-MCM-22) was systematically characterized by powder X-ray diffraction, N2 adsorption-desorption analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. The acidity of the materials was studied by temperature programmed desorption of ammonia analysis. The well-characterized Zn-MCM-22 catalyst was investigated for the Friedel–Crafts alkylation of benzene by benzyl chloride in liquid phase medium. A systematic investigation of various operating parameters like effect of different temperature, catalyst loading and reactant molar ratio was carried out. The Zn-MCM-22 found to be promising, further the catalytic activity remains stable over several recycles.

Carbon nanotube channels selectively filled with monodispersed Fe3−xO4 nanoparticles

Magnetic iron oxide (Fe3−xO4) nanoparticles (NPs) with high density and narrow size distribution were selectively cast inside or at the outer surface of the channels of carbon nanotubes (CNTs) by performing thermal decomposition of an organic iron precursor in liquid-phase medium in the presence of adequately pre-treated CNTs. The size of the Fe3−xO4 NPs generated by the synthesis is around 13 ± 3 nm and no agglomeration was observed thanks to the presence of oleic acid playing the role of surfactant in the synthesis medium. The selective filling of the Fe3−xO4 NPs inside the CNT channel was confirmed by X-ray diffraction, transmission electron microscopy (also in tomography mode) and X-ray photoelectron spectroscopy. Such NPs were found to be less sensitive towards oxidation compared to the same NPs synthesized without CNTs according to the powder X-ray diffraction and they display thus a higher saturation magnetization (65 emu g−1). Such a composite was found to be superparamagnetic at room temperature. Due to its new “magnetic state”, it could efficiently be employed in applications, which need both magnetic and electric properties, especially in catalysis in liquid-phase medium where the catalyst–product separation is facilitated by the magnetic properties of the catalyst.

Preparation and luminescence of (SBA-15)–Eu 2O 3 composite materials

In this study, (SBA-15)–Eu 2O 3 host-guest composites have been prepared with SBA-15 mesoporous sieve as host and Eu 2O 3 as guest via the solid-phase ultrasonic method and liquid-phase medium ultrasonic method. The host–guest composite materials showed the properties of luminescence. Four excitation peaks appeared in the excitation spectra of the samples. The excitation peaks are located at 397, 415, 466, 537 nm; 392, 408, 464, 532 nm and 393, 406, 465, 533 nm for the nano-Eu 2O 3, the liquid-phase medium ultrasonic method (LPMUM) and the solid-phase ultrasonic method (SPUM) samples, respectively. SBA-15 has the well-ordered hexagonal arrays of mesopores, which makes centrosymmetry of Eu 3+ higher in the prepared (SBA-15)–Eu 2O 3 samples. The intensity of 5D 0→ 7F 1 transition strengthens, and the intensity of 5D 0→ 7F 2 transition weakens.

Zinc Compounds Combined With Cyclodextrin Inhibit Growth of Helicobacter pylori In-vitro

Zinc compounds have anti-gastric ulcer activity in animal models and in man. Since Helicobacter pylori is a major aetiologic agent in peptic ulcer disease this raised the possibility that part of the anti-ulcer activity of zinc could be due to its effects on the growth of H. pylori. We therefore investigated the in-vitro effects of zinc sulphate and a slow-release zinc compound, zinc monoglycerolate (ZMG), on the growth of H. pylori cultured in either solid agar or liquid phase media (in microtiter plates). Growth media comprised buffered peptone adjusted to pH 5·1 and pH 7·2; the lower pH mimicks that in the stomach without unduly affecting the growth of H. pylori. A total of 26 strains comprising clinical isolates and standards were cultured with the zinc compounds for one to three days. The results showed that Zn2+ and ZMG alone had little effect on the growth of H. pylori in solid or liquid phase media at either pH. However, incorporating β-cyclodextrin (β-CyD, 1 mg mL−1) with both zinc compounds produced marked inhibition of growth in all strains at concentrations of 22·0–77·5 μg mL−1, with more pronounced inhibition at the lower pH. Zinc compounds inhibit growth of H. pylori when combined with β-CyD; the latter may aid penetrance of zinc compounds into the bacteria.

Benzoylation of anisole catalyzed by Ga/SBA-15 supported on carbon nanofibers composite

Abstract Carbon nanofiber composite (C-NFC) shows several advantages compared to the conventional supports which are usually employed in catalysis such as alumina, silica or activated charcoal. In this present work we have developed a new hybrid catalyst consisting of SBA-15 supported on C-NFC for the benzoylation reaction. The structured materials allow an important improvement of the reaction hydrodynamics and favor the mass transfer between the active phase and the reactants, especially in the liquid-phase medium, thus improving the selectivity toward desired products and increase the catalyst stability. The Ga/SBA-15(10)/C-NFC composite was further used as catalyst for Friedel–Crafts acylation of anisole in slurry bed. Cycling tests confirm the fradual deactivation of the catalyst which could be attributed to the pore plugging by carbonaceous residue which render inaccessible the active site localized inside the mesoporous channel to the reactant. These active sites localized inside the mesoporous channel are expected to be responsible for the para product formation by shape selectivity and thus, only the ortho product, which is formed on the gallium sites localized on the pore mouth, is observed on the deactivated catalyst. Such hypothesis is confirmed by depositing gallium phase on the poreless carbon nanofiber.

Kinetic Study of Synthesizing 1-(3-Phenylpropyl)pyrrolidine-2,5-dione under Solid−Liquid Phase-Transfer Catalytic Conditions Assisted by Ultrasonic Irradiation

The synthesis of 1-(3-phenylpropyl)pyrrolidine-2,5-dione (SUC-R) (1) was successfully carried out by reacting succinimide (SUC-H) (2) with 1-bromo-3-phenylpropane (RBr) (3) in a small amount of KOH and organic solvent solid−liquid phase medium under phase-transfer catalysis (PTC) and almost anhydrous conditions assisted by ultrasonic irradiation. The main purpose of this work was to obtain the kinetic behavior, activation energy, and the related parameters in the solid−liquid PTC reaction combined with the ultrasonic irradiation. Based on the experimental data, a rational mechanism for the reaction is proposed. The reaction followed a pseudo-first-order rate law. A rate expression was developed to describe the kinetic behaviors from which the apparent rate constant (kapp) of the organic-phase solution was obtained via experimental data. Kinetics of the reaction, including the effects of agitation speed, ultrasonic energy, amount of water, amount of potassium hydroxide, temperature, amount of tetrabutylammonium bromide (TBAB), volume of cyclohexanone, amount of SUC-H, quarternary ammonium salts, and organic solvents on the conversion of RBr and the apparent rate constant (kapp) were investigated in detail. Rational explanations to account for the resulting phenomena were provided.

Positive Frequency Shifts Observed Upon Adsorbing Micron-Sized Solid Objects to a Quartz Crystal Microbalance from the Liquid Phase

By specifically binding derivatized colloidal particles and physisorbing nonderivatized particles to the surface of a quartz crystal microbalance (QCM), we have observed positive shifts of frequency, Deltaf, in contrast to the negative frequency shifts typically found in adsorption experiments. Evidently, the Sauerbrey relation does not apply to this situation. A comparison of frequencies shifts and bandwidths on different overtones reveals a coupled resonance: at low overtones, Deltaf is negative, whereas it is positive at high overtones, with maximal resonance bandwidth observed at the crossover point. As predicted by the Dybwad model, the spheres bound to the surface form resonating systems on their own. A composite resonator is formed, consisting of a large crystal with resonance frequency omega and the adsorbed spheres with resonance frequency omega(S). In the case in which the resonance frequency of the small spheres (firmly attached to crystal), omega(S), is higher than the resonance frequency of the crystal, omega, Deltaf of the composite system is negative (leading to the Sauerbrey limit). In the opposite limit (that is, in the case of large adsorbed particles bound to the sensor surface via a sufficiently weak bridge) Deltaf is positive. Such a behavior is known from sphere-plate contacts in the dry state. Finite element calculation demonstrates that this phenomena is also plausible in liquid phase media, with Deltaf critically dependent on the strength of the sphere-plate contact. Operated in this mode, the QCM most likely probes the contact strength, rather than the mass of the particle.