查看更多>>摘要：Glabridin has important bioactivities in anti-cellular aging, anti-atherosclerosis, protecting the nervous system and inhibiting melanin. There is currently no efficient separation method for the large-scale production of high-purity glabridin due to its insolubility in water. This paper presents hydrophilic β-cyclodextrin derivatives for the reactive extraction of hydrophobic glabridin from organic phase to aqueous phase in a quaternary solvent extraction system. The variables that affect extraction efficiency were studied, including solvent type, extractant type and concentration, extraction time and temperature. The optimal extraction conditions were achieved, involving extractant of SBE-β-CD, water-ethanol (5:5, v:v)/n-octanol-n-hexane (3:7, v-v) as extraction system and temperature of 5 degree. The results show that SBE-β-CD has a strong inclusion capacity for glabridin with inclusion constants of 85.95 L/mol. The reactive extraction reaches equilibrium in five minutes, which is convinced to fractional extraction. It is a promising method for the large-scale selective separation of high-purity glabridin from crude extract of Glycyrrhiza glabra.
查看更多>>摘要：The Indigenous bio-bed technology with electrical cells were designed to evaluate the Nitrogen removal performance and other pollutants from the river water. The designed Indigenous bio-bed technology were taken an influent levels of CODcr at 250 mg/L, MH4-N and, NO3-N concentrations at 7.5 mg/L for the experiment. The device ran for 48 h for nitrogen remediation of the river water, thus, achieving removal efficiency of 85 %, 97 %, 98 %, 95 % and 92 % for CODcr, NH4-N, NO2-N, NO3-N and TIN, respectively. The highest power and current density generated were 486.86 mWm~(-3) and 4807.02 mA/m~3, respectively. The correlation of both the values of Voltage production and TIN removal performance is shown to be statistically as, R~2 of 0.9861 and 0.9999 of both open and close circuit mode of operation, respectively. The dominant phylum relative abundance deduced the close circuit mode of operation: higher relative abundance than the open circuit.
Jahaziel A. Sanchez-GomezJulian Cabrera-RuizSalvador Hernandez
11页
查看更多>>摘要：Crude glycerol has become very competitive due to its low price and its use as a platform molecule for the generation of high value-added chemical products. This work proposes a new process to produce acrylic acid from crude glycerol using intensified processes (reactive distillation schemes). An economic analysis was also carried out in relation to the total annual cost to determine the costs associated to each reactive scheme. It was determined that the proposed schemes are economically viable and represent considerable benefits such as the clear reduction in the number of processes equipment. At the same time, it has been determined that these processes can use crude glycerol as raw material to obtain acrylic acid with a purity greater than 90 % in mol. Likewise, the proposed schemes show a significant reduction in energy consumption, up to 74 %, to produce acrylic acid in contrast to previous reported works.
查看更多>>摘要：This study concerns the dynamic of particle-particle collision characteristics in a three-dimensional gas-solid tapered fluidized bed. To this aim, a two-way coupled discrete element method and computational fluid dynamics is used to obtain the position and velocity of particles in the bed. By post-processing of data, the collision characteristics such as the collision frequency, relative collision velocity, and contact time of colliding particles are calculated. Next, the effect of inlet air velocity (ν_(inlet)) on the particulate flow dynamics and collision characteristics is studied statistically. Predictive equations for collision parameters are obtained in terms of the dimensionless ν_(inlet) using the regression analysis. Furthermore, it is shown that the relative collision velocity has a Log-normal distribution and its parameters are computed in time. Additionally, the collision characteristics are calculated and analyzed in the different zones of the bed. The results indicate that no collision occurs at heights upper than 350mm for ν_(inlet) up to 6.8 times the minimum fluidization velocity. Finally, the particle-particle collision frequencies are compared with the Martin and Gidaspow models where, on average, the minimum differences at ν_(inlet) = 2.2m/s as 29.7 and 22.6s~(-1) and the maximum ones at ν_(inlet) = 0.7m/s as 48.1 and 29s~(-1), respectively.
查看更多>>摘要：Separation of oil-in-water emulsion is a formidable challenge for a large variety of aca-demia and industries involved in the fields of materials, environment, chemistry and resources. Here, microfiltration carbon membranes (MFCMs) were fabricated by the blending of polyacrylonitrile fibers (PANf) and phenolic resin as starting materials through the processes of shaping and pyrolysis. The functional groups, thermal stability, porous structure, microstructure, mechanical strength, morphology and hydrophilicity of the MFCMs were characterized by Fourier transform infrared spectrometer, thermogravimetric analyzer, bubble pressure method, X-ray diffraction, electronic universal tester, scanning electron microscope and water contact angle tester, respectively. The separation performance of MFCMs with respect to the removal of emulsified oil from wastewater was investigated by varying the PANf amount, reusability and antifouling ability. The results showed that the incorporation of PANf enhanced the thermal stability of the precursor membranes. As the PANf amount increases in precursor membranes, the average pore size and mechanical strength of MFCMs gradually decrease, together with the increment of porosity and hydrophilicity. The optimal oil rejection reaches to 94.2 %, along with the permeation flux of 15000 kg·m~(-2)·h~(-1)·MPa~(-1) for MFCMs made by PANf in a content of 3 %.
查看更多>>摘要：The suitability of marble waste (MARWAS) slurry as an alternative sorbent to limestone for wet flue gas desulfurization (WFGD) was studied by absorbing SO2 from air-SO2 mixtures in a semi-batch bubble column reactor. The concentration of SO2 at the inlet to- and exit from the reactor was measured using an infrared SO2 analyser (ZJRFAY36, Fuji, Japan). Percent removal efficiency (PRE) of SO2 and slurry saturation time (SST) were determined as functions of pertinent process variables. The maximum values of PRE and SST obtained were 99.8% and 40.83 min, respectively, for a slurry depth of only 3 x 10~(-2) m. Product gypsum was calcined to Plaster of Paris (PoP) using a modified electric furnace and characterized using XRD, TGA, and SEM analyses. A design criterion for the continuous absorption of SO2 using two semi-batch absorbers have been proposed that allows complete conversion of MARWAS and more than 99% PRE of SO2. The synthesized gypsum can be used to adjust the desired properties of cement products while the PoP as a construction material. A comparison of PRE of SO2 using MARWAS and limestone slurries showed its maximum value to differ by approximately ± 1%. MARWAS slurry can, therefore, be favorably employed for the WFGD.
查看更多>>摘要：Based on the fundamentals of microfluidics, a novel approach for the determination of liquid-liquid equilibria (LLE) of ternary systems was proposed. The system studied here consists of the compounds water, acetone, and toluene. This method was realized in a microfluidic set-up that consists of a microchannel, a camera for the determination of the position of the phase interface, and a micro density meter for measuring the densities of the conjugated phases at the outlet of the microchip. To determine the equilibrium phase compositions, an optimization problem was defined that minimized the difference between the experimentally determined and calculated ratio of the volumetric flow rates of the conjugated phases. The developed procedure uses information on the position of the phase interface in the microchannel and the phase densities, and requires previous knowledge of the binodal curve, which as shown in our previous work (Hiibner and Minceva, 2019) can be also determined using the same set-up. The obtained equilibrium phase compositions were in good agreement with literature data. Eventually, once the procedure is automatized to reduce the required measuring time and achieve full user independency, the proposed approach poses a cheap and fast alternative to conventional methods for measuring LLE.
查看更多>>摘要：This work addresses the influence of partially hydrophobic aluminum particles on the interfacial properties of o/w and w/o dispersions. For this purpose, drop size distributions are determined in an agitated tank followed by batch settling experiments after stirrer stop. In presence of hydrophobized aluminum particles, the type of dispersion (o/w or w/o) has an unexpected influence on coalescence behavior. Particles accelerate the coalescence for o/w dispersions (low oil fraction) but hinder the coalescence for w/o dispersions (high oil fraction). For a deeper understanding of this effect, an in-depth characterization and comparison of the drop size distributions of the two dispersion types was performed.
Zeeshan Ul HaqHafeez UllahMuhammad Nouman Aslam Khan
13页
查看更多>>摘要：Hydrogen production from the supercritical water gasification (SCWG) of sewage sludge (SS) is a sustainable and efficient process. However, the challenging and intricate task for the experimental technique is to find out the correlation between proximate, ultimate analysis and gasification conditions with H2 production. This process is complicated, expensive and requires many experimental techniques. To accurately predict and analyze the effect of input parameters on SCWG of SS process economically, an efficient model must be developed. The novelty of this study includes the consideration of four different machine learning (ML) methods integrated with Genetic Algorithm for the prediction, analysis, and evaluation of Hydrogen yield from the supercritical water gasification of sewage sludge. The ML methods included Support Vector Machine, Ensembled Tree, Gaussian Process Regression, and Artificial Neural Network. The results suggests that GPR is favored for predicting Hydrogen yield (Coefficient of determination (R~2) = 0.997, Root Mean Square Error (RMSE) = 0.093, and is highly recommended for dealing with complex variable-target correlation. On the other hand, the performance of Support Vector Machine (SVM) was poor with R~2 = 0.761 and RMSE = 2.479. The R~2 and RMSE for Ensembled Tree (ET) and Artificial Neural Network (ANN) was 0.994, 0.560 and 0.943, 1.521 respectively. The partial dependence plot shows that temperature, moisture content and pressure are among the effective parameters of SCWG. Furthermore, optimization techniques such as genetic algorithms are incorporated to optimize H2 production by tuning the ML hyperparameters. Additionally, a Graphical User Interface was developed by utilizing the optimized GPR model for ease in computing H2 yield.The optimum ML method integrated with GA will be beneficial for researcher to predict the H2 yield for the experimental work.
查看更多>>摘要：A one dimensional (1D) model accounting for the charge and mass transfer, biofilm formation and the electrochemical reactions that occur in a single chamber microbial fuel cell (SCMFC) operated at batch mode was developed. As the authors are aware, this simplified and easy to implement model for this design and operating mode is unique. The assumptions performed on the model development and the set of parameters used in the model predictions were carefully considered and chosen based on the operating and design conditions and following recommendations from literature. Despite the simplifications and assumptions performed, the model predictions are in good agreement with the experimental data, with a maximum power density of 36.7 mW/cm~2. The model predictions concerning the effect of the substrate concentration at the biofilm, anode and cathode overpotentials, cell voltage, current density and power density were also studied. The substrate concentration showed a higher impact on the anode overpotential for the medium to high current density values and predicted well the decrease in substrate availability for increasing current densities and higher anodic reaction rates. The model is rapidly implemented using simple numerical tools (like Excel and Matlab) being, therefore, suitable to seek for possibilities of optimizing the performance of a SCMFC by studying the impact of variations on the design parameters (such as membrane thickness, catalyst loading, electrodes type and thicknesses) and operating conditions (such as substrate concentration). This work demonstrated the value of the developed model in understanding the phenomena behind the MFC systems and on developing more efficient systems, towards an increase of their power output.
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