Aqueous Solutions Of 1-butanol Research Articles

Photocatalytic hydrogen production from butanol-water mixture over noble-metal free CuO/NiO/NiFe2O4 heterostructure

The photocatalytic hydrogen (H2) production has gained much interest in the past decades. Alcohol was typically used as a sacrificial reagent for the H2 evolution reaction. In the present work, the effect of primary alcohol on the photocatalytic H2 production over the CuO/NiO/NiFe2O4 composite was investigated. The composite was derived by calcining a CuO/NiFe-layered double hydroxide mixture at 973 K for 4 h. Through the synergistic effect of three components, the composite exhibited higher photocatalytic activity than the pristine CuO and NiO/NiFe2O4 under UV-visible light. The H2 production over CuO/NiO/NiFe2O4 increased from 50.3 μmol to 265.3 μmol upon the changing of sacrificial reagent from methanol to butanol as supported by the increase of the cathodic photocurrent in butanol aqueous solution. The insight mechanism was detailed by theoretical calculation. The co-adsorption of butanol on the catalyst surface resulted in a decrease in hydrogen atom adsorption-desorption free energy, which consisted of the higher H2 evolution activity compared to that of methanol system.

Effect of the self-rewetting fluids on heat transfer performance of gravity heat pipes with sintered porous wick

The distribution of the working fluid in a heat pipe directly affects the phase change heat transfer process. This paper explores how self-rewetting fluids (SRWF) and porous wicks affect the distribution of working fluids and heat transfer efficiency in gravity heat pipe (GHP). We sintered a porous wick onto the evaporator section and tested two working fluids: water and SRWF (3 % butanol aqueous solution). The filling ratio of the working fluid φ was varied from 11.5 % to 46 %. We found that at large filling ratios, porous wick surface will immerse in liquid, and at small filling ratios the heating surface will lack of liquid. Consequently, the GHP operates at a lower temperature at a filling ratio of 23 % compared to 11.5 % and 46 %. The type of working fluid significantly impacts the operating temperature and temperature uniformity. The Marangoni effect of the SRWF enhances the rewetting of the fluid in the porous wick, but this effect is only observed after the temperature reaches the inflection point (where the SRWF exhibits minimum surface tension). Before this point, the GHP operating temperature with SRWF is relatively higher than with water. Correspondingly, the temperature uniformity on the evaporator section is better when using SRWF. At φ = 23 %, Q = 500 W the temperature uniformity improved by 66 %. At Q = 660 W the evaporator heat transfer coefficient increased from 3991.6 W/m2K to 6130.5 W/m2K which is a 53.6 % improvement over water. We used an infrared camera to visualize the rewetting phenomenon of SRWF in the heated porous wick, confirming that SRWF can rewet the dry-out area, thus validating our hypothesis.

Transmission of butanol isomers in pervaporation based on series resistance model

Pervaporation (PV) has shown great potential in the separation of butanol aqueous solutions due to their economic and environmental benefits. This work applies polydimethylsiloxane (PDMS) composite membrane to separate four butanol isomers (n-butanol, isobutanol, sec-butanol and tert-butanol) in aqueous solution. Based on physical and chemical properties of butanol isomers, such as solubility, polarity and interaction parameter, we systematically study the transmission difference in the pervaporation process. The influence of feed concentration, temperature and permeate pressure on membrane performance of PDMS composite membrane are investigated. The results show that the contact angles of butanol isomers on the PDMS layer are 51°, 42.7°, 37.7°, 29.1° and the fluxes at 40 °C are 237.6 g m-2 h-1, 245.4 g m-2 h-1, 224.1 g m-2 h-1, 169.4 g m-2 h-1 for n-butanol, isobutanol, sec-butanol, and tert-butanol, respectively. Moreover, the similar compatibility principle is introduced to the series resistance model so the process simulation matches well with the antagonistic effect of water molecules on mass transfer of butanol isomers. The permeation activation energy is negative, indicating that the dissolution dominates the dissolution and diffusion process. In addition, low vacuum is not conducive to the separation of n-butanol from water. The research on isomers separation through pervaporation may pave a way to separate other solvents of similar properties.

Immersion cooling effect of dielectric liquid and self-rewetting fluid on smooth and porous surface

Dielectric liquid Novec 7300 and 5% 1-butanol aqueous solution are applied for immersion cooling of heater in order to investigate effect of nucleate boiling and self-rewetting on heat transfer. Experimental results are compared with water as common liquid for immersion cooling. In first part of study, bare heater is heated until temperature arrives at certain levels (from 100 °C to 500 °C), and then immersed in liquid for observing rapid cooling performance of these three solutions. In 5% 1-butanol binary solution, heater temperature decreases the fastest and stabilizes at the lowest level. Inversed thermal Marangoni flow induced by vertical temperature difference along heat surface is supposed to assist vapor bubbles separation and improve convective heat dissipation. From 200 °C, vapor film appears on the surface of heater immersed in Novec 7300 and water, whose thickness is dependent of surface temperature but independent of heat flux. In second part of study, immersion cooling performances of three testing liquids on heater with or without porous shells of different porosity are explored with increasing heating power. At different heat flux input, shell porosity, capillary effect, inverse thermal Marangoni effect and pool boiling stages influence heat transfer efficiency of each fluid-heater combination. A curve of optimal heat transfer coefficient is established, which is beneficial for selection of suitable fluid-heater combination.

Mechanism for sonochemical reduction of Au(III) in aqueous butanol solution under Ar based on the analysis of gaseous and water-soluble products

When an aqueous Au(III) solution containing 1-butanol was sonicated under Ar, Au(III) was reduced to Au(0) to form Au particles. This is because various reducing species are formed during sonication, but the reactivity of these species has not yet been evaluated in detail. Therefore, in this study, we analyzed the effects of Au(III) on the rates of the formation of gaseous and water-soluble compounds (CH4, C2H6, C2H4, C2H2, CO, CO2, H2, H2O2, and aldehydes), and the rate of Au(III) reduction as a function of 1-butanol concentration. The following facts were recognized: 1) for Au(III) reduction, the contribution of the radicals formed by the pyrolysis of 1-butanol was higher than that of the secondary radicals formed by the abstraction reactions of 1-butanol with ·OH, 2) ·CH3 and CO acted as reductants, 3) the contribution of ·H to Au(III) reduction was small in the presence of 1-butanol, 4) aldehydes and H2 did not act as reductants, and 5) the types of species that reduced Au(III) changed with 1-butanol concentration.

Fundamental Study on Heat Transport Device for Effective Utilization of Unused Heat

Recently, many countries have become increasingly interested in unused but possibly useful energy resources. Among these unused resources, the thermal energy produced around us can be used as a potential energy source for heating, cooling and power generation. This thermal energy is relatively stable on the supply side as waste heat in the industrial field. Heat transport devices are one of the important technology for the effective use of unused heat energy. This paper conducts basic research on devices that effectively transport heat below 200ºC. A pulsating heat pipe (PHP) is an excellent heat transport device based on the phase change of a working fluid. Experiments are performed to investigate the thermal performance of a PHP using different working fluids. The PHP consists of 20 parallel channels made of a copper capillary tube with an internal diameter of 1.8 mm. The PHP is filled with deionized water and an aqueous solution of 1-butanol as working fluids, with different filling ratios (FRs) in the range 50-60 vol.%. The 1-butanol aqueous solution is known as a self-rewetting fluid. The experimental results indicate that, in the case of self-rewetting fluid, stable oscillating motion in the PHP arises at the heat load regime lower than that with water. In addition, the effective thermal conductivity of the PHP with the highest concentration of self-rewetting fluid is higher than that with other fluids in the high heat load regime.

Ionic liquid modified graphene oxide-PEBA mixed matrix membrane for pervaporation of butanol aqueous solutions

This work explored a novel way to modify graphene oxide (GO) with ionic liquid (IL) and incorporate the modified GO into polyether block amide (PEBA) membrane for pervaporation of butanol aqueous solutions. The adsorption properties of GO and ionic liquid N-octylpyridiniunm bis (trifluoromethyl) sulfonyl imide [OPY][Tf2N] modified graphene oxide (IL-GO) for butanol and water were investigated via molecular simulation. Because ionic liquid [OPY][Tf2N] has good butanol affinity and hydrophobicity, the adsorption selectivity of butanol over water by the IL-modified GO increased by about 4 times compared with the pristine GO. Then IL-GO was incorporated into PEBA to fabricate mixed matrix membrane. The membrane was characterized, and the pervaporation performance of the membrane was evaluated. Pervaporation experiments showed that the incorporation of IL-GO is in favour of enhancing the membrane performance. Compared with pristine PEBA membrane, at 35 °C, for 2.5 wt% butanol aqueous solutions, the separation factor and permeation flux of the mixed matrix membrane with 1 wt% content of IL-GO were increased by 31.5% and 18.2%, respectively. Meanwhile, connecting ionic liquid to GO can effectively improve the membrane stability by preventing the loss of ionic liquid in the pervaporation process.

Effect of self-rewetting fluids on the liquid/vapor phase change in a porous media of two-phase heat transfer devices

This paper presents an experimental study of the phase change phenomenon in a porous medium. The tested working fluids are pure water and butanol aqueous solutions with different concentrations. In contrast to ordinary fluids, the surface tension of self-rewetting fluids exhibits a positive gradient beyond a certain temperature value. The experimental results indicate that the use of self-rewetting fluids (water/butanol) as working fluid significantly improves the performance of the capillary evaporator by decreasing the casing temperature. To explain the heat transfer enhancement mechanism, the phase change phenomenon is visualized for the two working fluids. It is shown that as the applied power increases, the shape of the vapor pocket that developed within the porous wick also increases for pure water until it reaches a stable shape. With respect to self-rewetting fluids, the shape of the vapor pocket decreases with increasing applied power allowing more efficient mass and heat transfers. Wettability, capillary pressure and Marangoni forces are the factors related to surface tension and contact angle that seem to be responsible for this heat transfer improvement for self-rewetting fluids.

Research on Heat Transfer Performance of the Open-Loop Micro Pulsating Heat Pipe with Self-Rewetting Fluids

As technology becomes increasingly miniaturized, extremely localized heat dissipation leads to the challenge of how to keep these devices from overheating. A pulsating heat pipe (PHP) is an excellent cooling device based on the phase change of a working fluid. Experiments are performed to investigate the thermal performances of a Micro Pulsating Heat Pipe (MPHP) using different working fluids. The MPHP consists of 20 parallel channels made of a copper capillary tube with an internal diameter of 0.8 mm. The MPHP is filled with ethanol, deionized water and an aqueous solution of 1-butanol as working fluids, with different filling ratios (FRs) in the range 40–70 vol.%. The 1-butanol aqueous solution is known as a self-rewetting fluid, i.e. a dilute aqueous solution of alcohols with a number of carbon atoms higher than four (such as 1-butanol and pentanol). The surface tension of self-rewetting fluids decreases gradually with an increase in temperature, reaching a minimum around 60 °C, and subsequently increases gradually at higher temperatures. Therefore, at relatively high temperature self-rewetting fluids flow towards the regions at higher temperature due to the Marangoni effect. This flow should improve the boiling phenomenon, which is very important in the heat transfer mechanism of the MPHP. The experimental results indicate that, in the case of self-rewetting fluid, the stable oscillating motion in the MPHP arises at the heat load regime lower than that with water. In addition, the effective thermal conductivity of the MPHP with the highest concentration of self-rewetting fluid is higher than that with other fluids in the high heat load regime.

Marangoni effect on pool boiling heat transfer enhancement of self-rewetting fluid

To clarify the Marangoni effect on nucleate pool boiling with different working fluids, a serial boiling experiments with the monocomponent fluid (water), the tradition binary fluid (5 wt% ethanol aqueous solution) and self-rewetting fluid (5 wt% butanol aqueous solution) have been comparatively carried out. During the pool boiling experiments, a boiling system using a horizontal heated wire was employed. The experimental results show that, due to Marangoni convection induced by the surface tension gradient, the critical heat flux (CHF) of the binary fluid (5 wt% ethanol aqueous solution) increased up to 1.52 times that of water, and the CHF of the self-rewetting fluid (5 wt% butanol aqueous solution) increased up to 1.91 times that of water. Utilizing dimensionless parameters with thermal Marangoni number (MaT) and solutal Marangoni number (MaS), the Marangoni effect have been quantitatively analyzed. It can be concluded that the Marangoni convection should be the key factors causing the pool boiling heat transfer enhancement.

Description of butanol aqueous solution transport through commercial PDMS pervaporation membrane using extended Maxwell–Stefan model

ABSTRACTThe mass transport of components during the pervaporation of binary butanol aqueous solutions using commercial PDMS membranes has been investigated. A simplified approach of the Maxwell–Stefan model was extended to include the effect of membrane swelling and temperature on the diffusion coefficients and sorption properties. Partial permeate fluxes obtained at different temperatures and concentrations have been fitted to determine the extended model parameters. The sorption properties and diffusion coefficients of components have been estimated using fitted parameters. Predicted values of the solubility and diffusivity were used to calculate and compare the permeability of the components under different operating conditions.Abbreviations: HPLC - High performance liquid chromatography; MS - Maxwell–Stefan; PDMS - Polydimethylsiloxane; SEM - Scanning electron microscope

Selective adsorption of water from aqueous butanol solution using canola-meal-based biosorbents

In the present paper, the capabilities of canola meal (CM)-based biosorbents for the selective water removal from aqueous solution of butanol were investigated for purifying butanol. The raw canola meal (RCM) after protein extraction was pretreated using 5% (v/v) sulfuric acid to enhance the water adsorption characteristics of CM. This pretreated canola meal (PCM) was used as an adsorbent along with the RCM adsorbent for selective water removal. Biosorbents were characterized by Fourier transform infrared, carbon hydrogen nitrogen sulfur (CHNS), Brunauer, Emmett, and Teller surface area, and X-ray diffraction. The surface area and micropore volume were increased in PCM. In addition, crystallinity index and CHNS content in PCM were also increased. Both the adsorbents were able to selectively adsorb water from the aqueous solutions of butanol. PCM demonstrated a higher water uptake and a higher final butanol concentration than RCM. The adsorption diffusion model better fits the kinetic data of water adsorption by PCM in a butanol solution containing 95.3 wt% water. The adsorption isotherm was also investigated. The mean free energy per molecule of adsorbate () based on Dubinin–Radushkevich theory indicated that water adsorption is favorable and water or butanol adsorption was physical in nature.

Marangoni Flow Induced Evaporation Enhancement on Binary Sessile Drops.

The evaporation processes of pure water, pure 1-butanol, and 5% 1-butanol aqueous solution drops on heated hydrophobic substrates are investigated to determine the effect of temperature on the drop evaporation behavior. The evolution of the parameters (contact angle, diameter, and volume) during evaporation measured using a drop shape analyzer and the infrared thermal mapping of the drop surface recorded by an infrared camera were used in investigating the evaporation process. The pure 1-butanol drop does not show any thermal instability at different substrate temperatures, while the convection cells created by the thermal Marangoni effect appear on the surface of the pure water drop from 50 °C. Because 1-butanol and water have different surface tensions, the infrared video of the 5% 1-butanol aqueous solution drop shows that the convection cells are generated by the solutal Marangoni effect at any substrate temperature. Furthermore, when the substrate temperature exceeds 50 °C, coexistence of the thermal and solutal Marangoni flows is observed. By analyzing the relation between the ratio of the evaporation rate of pure water and 1-butanol aqueous solution drops and the Marangoni number, a series of empirical equations for predicting the evaporation rates of pure water and 1-butanol aqueous solution drops at the initial time as well as the equations for the evaporation rate of 1-butanol aqueous solution drop before the depletion of alcohol are derived. The results of these equations correspond fairly well to the experimental data.

Study of self-rewetting fluid applied to loop heat pipe with PTFE wick

It’s the first using self-rewetting fluid with PTFE wick structure applied to Loop Heat Pipe System. PTFE wick structure has low thermal conductivity, low sintering temperature thus low cost and high anti-oxidation production for long term using which can also overcome heat leakage when operating. It effectively improves the performance of traditional metal wick structure. However, with the hydrophobic of PTFE material, we can’t directly use water as working fluid. Therefore, this paper adds butanol in water to form self-rewetting fluid which not only easily goes through PTFE wick structure but spontaneously supplements the heating surface, making system operates successfully.After testing the surface tension and heat-transfer performances of LHP system, it shows that LHP system begins to work by adding 3wt% butanol aqueous solution. It has the maximum heat capacity of 400W, the minimum thermal resistance 0.32°C/W and heat flux 20W/cm2 when increasing to 6wt% butanol aqueous solution. It’s also the first point making LHP system operate successfully. Compared to the water-nickel system, butanol-PTFE system halving the total thermal resistance, heat flux increases over 50%, and the lower operating temperature and pressure, thus it can have higher stability and security.

Energy saving potential of hybrid membrane and distillation process in butanol purification: Experiments, modelling and simulation

Pervaporation experiments of dilute aqueous butanol solutions were carried out with three PDMS [poly(dimethyl siloxane)] membranes. Based on the experimental results of the best performing membrane a regression for both butanol and water permeability was done in the software R and implemented in a user defined pervaporation unit operation in the software Aspen Custom Modeler. With the implementation of the pervaporation step in Aspen Plus the hybrid pervaporation and distillation purification chain can be simulated in consistent way.Calculation of pervaporation of a 0.5wt% BuOH-water solution with the experimentally investigated PDMS membrane results in a permeate stream with a concentration of 9wt% BuOH. Application of membrane distillation resulted in a permeate butanol concentration of only 3wt% and a considerable higher specific energy demand compared to pervaporation.For product purities of 99wt% of BuOH a hybrid pervaporation and distillation process saves around 50% of the energy demand compared to state of the art distillation. A sensitivity analysis of the pervaporation step reveals, that for the hybrid pervaporation and distillation process compared to state of the art distillation the energy demand decreases already exceeding 5wt% BuOH in the permeate stream.

ZIF-7/PDMS mixed matrix membranes for pervaporation recovery of butanol from aqueous solution

Abstract In this contribution, zeolitic imidazolate framework (ZIF-7)/polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) with uniformly dispersed ZIF-7 were fabricated. The homogeneous dispersion of ZIF-7 nanoparticles in PDMS matrix and better interface compatibility were characterized by SEM and EDS. PV performance reveals that the MMMs display increased total flux and the highest separation factor occurs at 20 wt% ZIF-7 loading, which were 1689 g m −2 h −1 and 66 respectively as compared to 1080 g m −2 h −1 and 51 for pure PDMS membrane when separating 1 wt% butanol aqueous solution at 60 °C. The total flux reaches 3496 g m −2 h −1 with 80 wt% butanol in permeate for the enrichment of 5 wt% butanol solution at 60 °C. The enhanced flux may result from enlarged free volume in the polymer matrix caused by the incorporation of ZIF-7 nanoparticles. Moreover, the super-hydrophobic ZIF-7 pore channels and butanol preferential permeation may contribute to the improvement of separation factor. The result also shows that there is a 21.1% reduction of energy barrier for penetrant transportation for 20 wt% ZIF-7 filled PDMS membrane as compared to pristine PDMS membrane. A long period of pervaporation experiment was also carried out to investigate the structure stability of the ZIF-7/PDMS membrane, and the MMM remains intact during the 240 h continuous operation, which is the key to industrial application for membrane-based separation process. All above indicated that ZIF-7 is a good filler to fabricate butanol permselective pervaporation membranes for butanol separation and enrichment.

Study of self-rewetting fluid applied to loop heat pipe

This study investigated the application of self-rewetting fluid to loop heat pipe (LHP) and its effect on the heat transfer performance of LHP, proposing a most suitable solute and concentration for LHP. At a certain temperature, a self-rewetting fluid, contrary to common newtonian fluids, has the ability to reverse its surface tension's trend, inducing colder fluid to flow to the heated surface and delaying the occurrence of dry-out in LHP during operation. The most important variables for a self-rewetting fluid are its concentration and solute. Thus, this study focused on a few self-rewetting fluids (including butanol, pentanol, and hexanol aqueous solutions); the surface tensions of these fluids at different concentrations were measured to find the best self-rewetting fluid, and then it was applied to LHP as working fluid to investigate its effect on the heat transfer performance.Results of surface tension measurement showed that, concerning the concentration of a self-rewetting fluid, the optimal concentration for a self-rewetting fluid was its saturation concentration; concerning the solute of a self-rewetting fluid, after comparing all the tested working fluids at the optimal concentration, 6% butanol aqueous solution was the best type of self-rewetting fluid. Results from applying 6% butanol to LHP as working fluid for performance testing showed that the critical heat load was 650 W and the total thermal resistance was 0.25 ° C/W. Compared with LHP with regular working fluid, the critical heat load was 2.5 times higher and total thermal resistance decreased by about 60%, indicating high potential for self-rewetting fluids to enhance the heat transfer performance of LHPs.

Hollow fiber modules with ceramic-supported PDMS composite membranes for pervaporation recovery of bio-butanol

The practical application of hollow fiber membranes for pervaporation technology has been received growing attention in recent years. This work reports the development of hollow fiber modules of ceramic-supported polydimethylsiloxane (PDMS) composite membranes applied for pervaporation process. Computational fluid dynamics (CFD) technique was used to simulate and optimize the flow field distribution in the modules with different packing density and cross-section layout. The hollow fiber modules with proposed configurations were fabricated in our lab and evaluated by pervaporation measurement in model butanol aqueous solution and real fermentation broth. The results suggested that the design of packing density and cross-section layout could realize the optimization of module configuration. The optimized module filled with 7 bundles of hollow fiber membranes at a high packing density of 560m2/m3 exhibits a high and stable performance in the real ABE fermentation broth during 120h continuous operation at 40°C. The average total flux was 1000g/m2h and separation factor were 6.4 for ethanol, 22.2 for butanol and 28.6 for acetone, respectively. Our results demonstrated that the hollow fiber modules developed in this work could be competitive candidates for the practical application in pervaporation recovery of bio-butanol.

Investigation of sorption characteristics of polymeric membranes containing ionic liquids for n-butanol recovery from aqueous streams

Ionic liquid–polydimethylsiloxane (IL–PDMS) blending membranes were prepared to separate n-butanol from aqueous mixtures. The ionic liquids (ILs) used were [hmim][PF6] (1-hexyl-3-methylimidazolium hexafluorophosphate), [bmim][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate), and [bmim][TF2N] (1-Butyl-3-methylimidazolium bistrifluoromethylsulfonylimide). Sorption experiments were carried out to define the sorption and separation capacity of the blending membranes using aqueous butanol solutions in the range of 1–5% (wt), and also sole solvents of butanol and water. The desorption experiments allowed to determine the selectivity of the membranes as the liquid composition inside the membrane could be obtained with the desorption step. The results obtained by IL–PDMS blends were compared with the results obtained by unblended PDMS membranes to show the effect of the IL in the PDMS matrix. [Hmim][PF6]–PDMS-blended membranes showed lower selectivity. The addition of [bmim][PF6] to PDMS enhanced the selectivity and sorption amounts mildly. [Bmim][TF2N]–PDMS-blended membranes presented the best sorption and selectivity results showing a great affinity to butanol and a reasonable rejection to water.

302 1-ブタノール水溶液のプール沸騰熱伝達特性に関する研究(OS3-(1),OS3 オーガナイズドセッション≪熱・流体・エネルギー変換工学の進展≫)

This study is concerned about the pool boiling heat transfer characteristic of 1-butanol aqueous solution. Two different concentrations of 1-butanol 1.0wt% 5.0wt% dissolve in water were prepared and used 0.3mm line of platinum at heating test section. The test results show that Critical heat flux of the 1-butanol aqueous solution is increase with increase in density. And as a result of having compared the existing correlations with the experimental data, it showed good correspondence.