Solvent Flow Rate Research Articles

Assessment of mass transfer performance using the two-film theory and surrogate models for intensified CO2 capture process by amine solutions in rotating packed beds

CO2 capture is a crucial aspect of attempts to mitigate climate change. The purpose of this study is to investigate the impacts of essential operating parameters on the mass transfer performance of absorbing CO2 in rotating packed beds (RPBs). A multilayer perceptron neural network (MLPNN) model with the Levenberg-Marquardt learning algorithm, a mass transfer model using the two-film theory, and an empirical correlation model were developed to predict the overall gas-phase volumetric mass-transfer coefficient (KGaV) for RPB-based CO2 absorption. The developed MLPNN model showed excellent agreement with the actual data, with an MSE of 0.0357, an AARD of 7.4%, and an R2 of 0.9839. A sensitivity analysis was conducted using Taguchi orthogonal array design on distinct mass transfer correlations. The results of the two-film theory and surrogate models for the diethylenetriamine (DETA) solvent were compared. The MLPNN model provided better predictions than other developed models with an AARD of 13% for CO2H2O-DETA system. Therefore, the effects of operating parameters such as concentration, temperature, solvent flow rate, and rotational speed on KGaVand CO2 removal efficiency were evaluated using the MLPNN model. Finally, an empirical correlation was proposed to predict KGaVas a function of operational parameters.

Modeling the Production Process of Lignin Nanoparticles Through Anti-Solvent Precipitation for Properties Prediction.

Global warming has recently intensified research interest in renewable polymer chemistry, with significant attention directed towards lignin nanoparticle (LNP) synthesis. Despite progress, LNP industrial application faces challenges: (1) reliance on kraft lignin from declining raw biomass processes, (2) sulfur-rich and condensed lignin use, (3) complex lignin macroparticles to LNP conversion, using harmful and toxic solvents, and, above all, (4) lack of control over the LNP production process (i.e., anti-solvent precipitation parameters), resulting in excessive variability in properties. In this work, eco-friendly LNPs with tailored properties were produced from a semi-industrial organosolv process by studying anti-solvent precipitation variables. Using first a parametric and then a Fractional Factorial Design, predictions of LNP sizes and size distribution, as well as zeta-potential, were derived from a model over beech by-products organosolv lignin, depending on initial lignin concentration (x1, g/L), solvent flow rate (x2, mL/min), antisolvent composition (x3, H2O/EtOH v/v), antisolvent ratio (x4, solvent/antisolvent v/v), and antisolvent stirring speed (x5, rpm). This novel chemical engineering approach holds promise for overcoming the challenges inherent in industrial lignin nanoparticle production, thereby accelerating the valorization of lignin biopolymers for high value-added applications such as cosmetics (sunscreen or emulsion) and medicine (encapsulation, nanocarriers), a process currently constrained by significant limitations.

High‐Throughput Electrospinning of Unmodified and Aminated Poly(Pentafluorostyrene) for Fiber‐Reinforced Proton Exchange Membranes

AbstractThis study demonstrates a high‐throughput fabrication of fiber interlayers for proton exchange membranes based on poly(pentafluorostyrene) (PPFSt) and its aminated derivatives. The fibers are produced by electrospinning, where the parameters are carefully screened. The controlled parameters are solvent composition, weight percentage, voltage, flow rate, and temperature, controlled with a self‐designed heating jacket. The parameters are iterated toward optimized fiber structure and maximum output. The yielded fibers are infiltrated with Nafion and sulfonated polymer from bisphenol AF and decafluorobiphenyl (SFS001) by spray‐coating and doctor blading to obtain the fiber‐reinforced proton exchange membranes. Tensile tests reveal a higher Young's modulus and yield stress than pure Nafion. Here, the basicity of the aminated PPFSt fibers correlates with the Young's modulus due to improved acid‐base interactions between amine groups and sulfonic acid. The acid‐base interactions influence the composite membrane's proton conductivity, varying from 23 mS cm−1 for strongly alkaline fibers to 69 mS cm−1 for non‐basic fibers. These findings can be transferred to fabricating fiber reinforcements beyond routinely used poly(benzimidazoles).

Simulation of a system to simultaneously recover CO2 and sweet carbon-neutral natural gas from wet natural gas: A delve into process inputs and units performances

The growing need for carbon-neutral energy solutions necessitates the development of efficient systems for carbon dioxide (CO2) recovery and the production of sweet carbon-neutral natural gas (CNNG) from wet natural gas. Despite existing approaches, limitations in process optimization, solvent efficiency, and output purity persist. This study aims to address these gaps by simulating a system for simultaneous recovery of CO2 and CNNG using an integrated three-stage process, modeled in Aspen Plus V8.8. The unique aspect of this work lies in employing the ENRTL-RK base model, coupled with sensitivity analyses to optimize input parameters across 13 interconnected process units, including compressors, heat exchangers, and extraction columns. Key innovations include the novel configuration of units, yielding a recovery efficiency of 95.94% for CNNG and a CO2 purity of 93.185% at optimal conditions, surpassing conventional methods. The performance of the monoethanolamine (MEA) solvent was enhanced by careful adjustment of input parameters, improving its absorption efficiency by 12% compared to standard operational settings. Sensitivity analysis revealed critical parameters such as feed pressure and solvent flow rate as primary drivers for maximizing output efficiency. This study also provides a detailed quantitative assessment of power requirements, with a compressor brake horsepower (BHP) of 18,2605 watts at 110 bar discharge pressure. It addresses the existing research gap by introducing a systematic approach to process optimization, significantly improving the purity and recovery of CNNG and CO2 while minimizing energy consumption. The results not only demonstrate the viability of this process but also provide a foundation for further refinement in sustainable gas processing technologies.

Green Technology for Baru Oil Extraction Using Solar Energy: Assessing Extraction Efficiency and Process Parameters.

This study explores the application of solar concentrator technology for Baru oil extraction, a crucial resource in various industries. Through systematic experimental investigations, the effects of particle size and solvent flow rate on extraction efficiency were evaluated. Results demonstrate that smaller particle sizes (1.01 mm) significantly enhance extraction efficiency, achieving yields up to 89.25%, compared to larger particles (2.18 mm) with yields averaging 54.32% (±3.2%). Additionally, the solvent flow rate of 25 mL/min maximized extraction efficiency. These findings highlight the critical influence of particle size and solvent flow rate on extraction performance and underline the potential of solar-assisted leaching as a sustainable and environmentally friendly alternative to conventional extraction methods. The research provides a novel contribution to the field by advancing sustainable oil extraction practices and offering a viable solution for small-scale producers to increase the value of their agricultural products.

Elucidating flow-directed 98% CO2 absorption using millimeter-sized coiled flow inverters: Nanocellulose-aided sustainable scope

The Sustainable Development Goals (SDGs) adopted by the United Nations drive the global efforts to discover a sustainable carbon capture method for the reduction of anthropogenic CO2 emissions. Concentrated alkanolamine solutions are being used as CO2 capture mediums for batch processes amid several disadvantages, such as energy intensiveness and poor efficiency. In this work, millimeter-sized coiled flow inverters (CFI) have been explored as a point-source CO2 capture tool for highly efficient, continuous operations. Solvent and CO2 gas flow rates are found to dictate the slug flow regime and, more specfically, slug lengths. High interfacial area and residence time remain the driving factors for enhanced CO2 capture using CFI. About 98% CO2 absorption efficiency has been achieved for 3% aqueous diethanolamine solution in CFI . The efficacy of nanocellulose, a sustainable nanomaterial has been unearthed for CO2 capture at low flow rate.

Study of ship-based carbon capture optimization considering multiple evaluation factors and main engine loads

Ship-Based Carbon Capture (SBCC) technology presents a promising approach to reduce greenhouse gas emissions in the marine transportation. Solvent-based carbon capture has emerged as a leading technology for SBCC, primarily due to its low retrofit costs and effectiveness in treating flue gas with low carbon content. However, challenges remain in optimizing system operation efficiency under the variable conditions of ship main engine loads and in understanding the mechanisms by which process parameters influence key evaluation factors. Consequently, this study established a pilot-scale experimental platform for solvent-based SBCC and developed a carbon capture model based on it. The influence of process parameters, such as main engine exhaust flow rate and liquid/gas ratio (L/G), on the evaluation factors was thoroughly explored. With the utilization of Shapley Additive Explanations (SHAP) analysis to quantify the influence of process parameters on the evaluation factors, a multi-objective optimization equation is proposed. The combination of machine learning and optimization algorithms offers an efficient approach for determining the optimal process of the SBCC system under different main engine loads. The research results show that the main engine exhaust flow rate is the most important process parameter affecting the carbon capture rate (CR), with an influence ratio as high as 64.33%. As the main engine exhaust flow rate increases, the maximum CR decreases from 97.84% to 61.13%. Although the extreme value of the regeneration energy consumption (REC) also decreases from 6.66 to 4.42 GJ/t CO2, the solvent flow rate's influence on REC is also significant, with influence ratios of 38.49% and 35.53%, respectively. A data-driven approach examined the optimal operating conditions at eight main engine loads, achieving a carbon capture rate prediction error of only 1.42% and a maximum REC error of only 0.55 GJ/t CO2. This study provides essential guidance for assessing the suitability of SBCC systems.

Lignocellulose Treatment Using a Flow-Through Variant of OrganoCat Process.

This study adapts the biphasic OrganoCat system into a flow-through (FT) reactor, using a heated tubular setup where a mixture of oxalic acid and 2-methyltetrahydrofuran (2-MTHF) is pumped through beech wood biomass. This method minimizes solvent-biomass contact time, facilitating rapid product removal and reducing the risk of secondary reactions. A comparative analysis with traditional batch processes reveals that the FT system, especially under severe conditions, significantly enhances extraction efficiency, yielding higher amounts of lignin and sugars with reduced solid residue. Notably, the FT system shows partial hydrolysis of the cellulose, which increases with temperature while not producing significant amounts of furfural or 5-HMF, indicating more efficient depolymerization of polysaccharides without substantial sugar degradation. A statistical design of experiments (DOE) using a Box-Behnken design elucidates the influence of process variables (time, solvent flow rate, temperature) on the yield. Key findings highlight reactor temperature as the dominant factor affecting yields, with process time showing a significant but less pronounced impact. This study demonstrates the potential of the FT OrganoCat system for efficient lignocellulosic biomass fractionation and represents an advancement towards continuous lignocellulose processing, contributing to our knowledge of process optimization for improved biorefinery applications.

Heat-integrated process improvement of petroleum refinery FCC light-ends separation

This research presents a methodology for investigating and proposing operational changes that can improve product recovery, heat recovery, and economics of a gas concentration unit of a FCC plant. The methodology starts by collecting relevant information from an existing plant, followed by development of a simulation model of a gas concentration unit in Aspen HYSYS. Next, the developed model is used to conduct optimisation studies to identify process changes (solvent temperature, operating pressure, solvent flow rate, solvent composition and inter-stage cooling) that improves product recovery, heat recovery, and economics. Key findings from this research includes the following trade-offs: increasing operating pressure from 1300 kPa to 1700 kPa increases gasoline and LPG recovery by 1% and 0.4% respectively whilst heat recovery and cooling water demand increases by 0.5% and 0.1%, leading to total benefit increase of 1%; increase in recycled gasoline flow rate by 9628 kmol/h (20% of initial flow rate) improves recovery of gasoline and LPG by 0.1% and 0.3% and heat recovery and cooling water demand by 18% and 77%, but steam generation decreases by 35%, which results to decrease in benefit of 1%; increasing C6 content of solvent (unstabilized naphtha) by 50 kmol/h increase in gasoline recovery 7.5% and heat recovery and cooling water demand increases by 0.1% and 1%, and benefit increases by 5%; for ambient cooling medium, varying solvent temperature and pumparound return temperature (inter-stage cooling) does not improve product recovery and heat recovery. Analysis of results indicate that high C6 composition in solvent has the highest impact on product recovery, heat recovery, and process economics compared with other degrees of freedom.

Flexibility analysis on absorption-based carbon capture integrated with energy storage

Post-combustion carbon capture in power plants is essential in reducing greenhouse gas emission. As the available heat in the plant is instable in time, it becomes a challenge to maintain the efficient operation of capture system. The lean/rich solvent storage proves to be a potential way for the capture system to keep high CO2 capture rate. However, the performance of the integrated system under different operating conditions is not fully evaluated, especially for the match criterion of lean/rich solvent process. The impact factors of single and coupled operating conditions of solvent storage still remain unclear. In this work, system performance during peak/off-peak period is first evaluated. Results indicates that heat duty, split ratio, solution concentration and absorption solvent flow rate are key factors for CO2 capture rate. Then, system performance under continuous operation is explored at the global CO2 capture rate from 0.918 to 0.978. It demonstrates that maintaining a relatively equal CO2 capture rate during peak/off-peak period efficiently improves the global CO2 capture rate, which can be achieved by adjusting flow rate and split ratio of solvent. Finally, volume and cost of integrated CO2 capture with solvent storage are compared with that of CO2 capture with heat storage. The volume of solvent storage decreases by over 69% and the cost of solvent storage decreases by over 84%, which indicates a promising application in terms of technical and economic aspects.

Direct air capture with amino acid solvent: Operational optimization using a crossflow air‐liquid contactor

AbstractDirect air capture (DAC) is a negative emission technology for removing CO2 from the atmosphere to maintain the CO2 level within a reasonable range so as to address greenhouse effects. In this study, the operational optimization of lab‐scale DAC has been investigated using a crossflow air‐liquid contactor loaded with a three dimensionally printed Gyroid packing structure and a potassium sarcosinate solvent. The effects of various parameters, including feed air flow rate, liquid solvent flow rate, contactor geometry, and ambient temperature, are examined. The results demonstrate that the Gyroid packing design achieves comparable CO2 capture performance to conventional packed beds but with a significantly lower pressure drop of up to 77.8%, suggesting its potential as an efficient and cost‐effective solution for gas–liquid contactors in DAC. Additionally, the study explores the climate impact on CO2 capture performance and finds that as the air temperature increases from 35 to 95°F at a fixed relative humidity of 80%, the CO2 capture rate increased from 23.2% to 46.8% with better stability. The research highlights the importance of optimizing contactor design and operational conditions to improve the CO2 capture rate and feasibility of DAC systems as a negative emission technology for addressing greenhouse effects.

Scaling the electrophoretic separation of rapeseed proteins and oleosomes

Gentle extraction of ingredients from raw materials is essential for high-quality food ingredients and can lead to reducing the use of water, chemicals, and energy in the extraction. For example, a simple aqueous extraction can yield a mixture of oil, in the form of a natural oil-in-water oleosome emulsion, and proteins. The oleosomes and proteins can then be further separated in a next step. We explored a continuous counter-current electrophoretic process that separates oleosomes and proteins based on their electrophoretic mobility by balancing an electric field with an opposing solvent flow. The separation is accomplished through the retention of the component with the higher electrophoretic mobility, the oleosomes, and the passage of the proteins, having lower mobility. The fluxes of oleosomes and proteins from rapeseed, after aqueous extraction, were analyzed as a function of the electric field (0–75 Vcm−1) and 1.2 ± 0.1 mLmin-1 solvent flow rate. At 50 Vcm−1, the permeation flux of proteins was 10-fold higher than that of oleosomes, as shown by the selectivity increasing to 9.84 from 1.90 at 25 Vcm−1. The difference in their flux promises to become more pronounced under an increasing treatment duration, but two main technical limitations, electrolysis-based pH alteration and membrane fouling, restrict further separation. We expect the listed challenges can be mitigated with the addition of electrode rinse chambers and the use of larger pore size membranes.

Hybrid Advanced Control Strategy for Post-Combustion Carbon Capture Plant by Integrating PI and Model-Based Approaches

Even though the energy penalties and solvent regeneration costs associated with amine-based absorption/stripping systems are important challenges, this technology remains highly recommended for post-combustion decarbonization systems given its proven capture efficacy and technical maturity. This study introduces a novel centralized and decentralized hybrid control strategy for the post-combustion carbon capture plant, aimed at mitigating main disturbances and sustaining high system performance. The strategy is rooted in a comprehensive mathematical model encompassing absorption and desorption columns, heat exchangers and a buffer tank, ensuring smooth operation and energy efficiency. The buffer tank is equipped with three control loops to finely regulate absorber inlet solvent solution parameters, preventing disturbance recirculation from the desorber. Additionally, a model-based controller, utilizing the model predictive control (MPC) algorithm, maintains a carbon capture yield of 90% and stabilizes the reboiler liquid temperature at 394.5 K by manipulating the influent flue gas to the lean solvent flowrates ratio and the heat duty of the reboiler. The hybrid MPC approach reveals efficiency in simultaneously managing targeted variables and handling complex input–output interactions. It consistently maintains the controlled variables at desired setpoints despite CO2 flue gas flow disturbances, achieving reduced settling time and low overshoot results. The hybrid control strategy, benefitting from the constraint handling ability of MPC, succeeds in keeping the carbon capture yield above the preset minimum value of 86% at all times, while the energy performance index remains below the favorable value of 3.1 MJ/kgCO2.

Rapid purification and scale-up of tilianin using counter-current chromatography with rectangular horizontal tubing

In counter-current chromatography (CCC), linear scale-up is an ideal amplification strategy. However, when transferring from analytical to predictable preparative processes with high throughput, linear scale-up would be challenging due to limitations imposed by differences in instrument parameters, such as gravitational forces, tubing cross-section area, tubing length, column volume and flow rate. Some effective scale-up strategies have been studied for different instrument parameters, but so far, these scale-up works have only been tested on standard circular (SC) tubing.The previous research of our group found that rectangular horizontal (RH) tubing can double the separation efficiency compared with conventional SC tubing, and has industrial production potential. This paper used the separation of tilianin from Dracocephalum moldavica L. as an example to demonstrate how to scale up the optimized process from analytical SC tubing to preparative RH tubing. After systematic optimization of solvent systems, sample concentration and flow rate on the analytical CCC, the optimized parameters obtained were successfully transferred to the preparative CCC. The results showed that a crude sample of 2.07 g was successfully separated using a solvent system of n-hexane - ethyl acetate - ethanol - water (1:4:1:5, v/v/v/v) in reversed phase mode, and the three consecutive separations produced a total of 380 mg tilianin in 75 min with high purities of 98.3%, as analyzed by HPLC. The total throughput achieved from the analytical to semi-preparative scale was improved by 138 times (from 12 mg/h to 1.66 g/h), while the column volume was increased by only 46.5 times (from 15.5 mL to 720 mL). This is the successful application of CCC for the separation and purification of tilianin. Given that SC tubing is the traditional configuration for CCC columns, this study is a necessary step to prove the applicability of RH tubing columns for routine use and potential large-scale industrial applications.

Post-combustion carbon capture process modeling, simulation, and assessment of synergistic effect of solvents

Post-combustion carbon capture appears to be a promising solution to reduce the emission of carbon dioxide (CO2) from power plants that generate electricity using either coal or natural gas. In addition, carbon capture process efficiency, capacity, and energy consumption have become challenging against the performance of the capture process. However, synergistic effect due to solvents blend has gained attention to reduce the process energy consumption and enhance process efficiency. In this study, blends of methyldiethanolamine (MDEA) and piperazine (PZ) at different concentrations were investigated using a validated post-combustion capture process model using Aspen HYSYS. Results were compared with 30 wt% monoethanolamine (MEA) as reference case. The effective process variables are concentration of solvents, the amount of water and solvent in the makeup section, viscosity of solvent, energy consumed in different process stages, and the amount of lean solvent flow rate. These variables were studied against fixed process variables using rate-based model. The study shows that using (43 wt% MDEA/7 wt% PZ) for post-combustion carbon capture needs 2.53 MJ/kgCO2 regeneration energy for 88.5% process efficiency compared to 4.003 MJ/kgco2 for 30 wt% MEA without the need for any process modifications. In addition, it was found that solvents synergistic effect contributes to resolving the drawbacks of post-combustion capture that will enable the high utilization of the process and contribution to reduce the consequences effect of climate change. Therefore, the study will help policymakers, industries and encourage researchers towards the large-scale commissioning of blended solvent -based post-combustion capture process.

Modeling, Simulation, and Membrane Wetting Estimation in Gas-Liquid Contacting Processes Including Shell-Side Reaction: Biogas Upgrading Using DEA Solution.

The basic principles of a steady-state mass transfer model and the resistance-in-series film model are assessed with the aid of a series of experiments in a gas-liquid contact membrane mini-module (3 M Liqui-Cel MM-1.7 × 5.5) using an aqueous solution of diethanolamine (DEA) of 0.25 M (mol/L) for biogas upgrading. Experimental data show that CO2 removal may exceed 67% and reach 100% in combination with the highest possible recovery of CH4 when employing biogas flow rates in the range of 2.8 × 10-5 - 3.6 × 10-5 m3/s and solvent flow rates within 0.47 × 10-5 - 0.58 × 10-5 m3/s. For the experimental data set, a correlation has been developed, effectively interpolating CO2 removal with the gas and liquid flow rates. The wetting values calculated are concentrated close to each other for the same liquid flow rate without considerably depending on the gas flow rate, especially when applying the Hikita-Yun (reaction rate-shell-side correlation) compared with the Hikita-Costello pair. Furthermore, the calculated wetting diminishes with increasing liquid flow rate, a result that is consistent with previous modeling attempts and relevant literature indications. The assumption of enhanced mass transfer in the liquid-filled part of the membrane pores due to the reaction is scrutinized, leading to objectionable computational wetting values. It is shown that for a concentration of DEA equal to 0.25 M the Hatta numbers and the enhancement factors are not equal in the whole reaction path; thus, the choice of the shell-side correlation has an appreciable impact on the overall analysis, especially for the determination of the wetting values.

Tuning parameters of single quadrupole mass detector hyphenated to supercritical fluid chromatography for enantioseparation of synthetic cathinones

In our previous paper, we introduced a new method for the enantioseparation of cathinones on chiral zwitterion ion exchangers by SFC-ESI-MS with an inverse make-up solvent gradient. The inverse gradient enabled us to stabilize electrospray ionization while simultaneously increasing MS response. In this study, we fine-tuned our previously optimized SFC-ESI-MS method and compared its efficiency with that of the default ESI-MS method. To enhance analyte detection, we designed a complex series of experiments in which all combinations of the following three parameters were evaluated: cone voltage (5 to 27 V), probe temperature (250 to 550 °C) and capillary voltage for positive ionization (0.3 to 1.5 kV). After optimization, various ratios of the make-up solvent (methanol/water/formic acid) introduced before entering the ESI ion source were also tested. Despite this comprehensive testing regime, there were no significant differences between the results obtained for the tuned and default ESI-MS parameters. Similarly, the most suitable make-up solvent composition was the originally used ratio of 90/10/0.1 (v/v/v). These results reinforce the findings of our previous paper, in which we optimized the make-up solvent flow rate and showed its significant impact on ESI-MS response.

Taguchi approach for assessing supercritical CO2 (sCO2) fluid extraction of polyhydroxyalkanoate (PHA) from Chlorella Vulgaris sp. microalgae

This research explicitly investigates the utilization of Chlorella Vulgaris sp. microalgae as a renewable source for lipid production, focusing on its application in bioplastic manufacturing. This study employed the supercritical fluid extraction technique employing supercritical CO2 (sCO2) as a green technology to selectively extract and produce PHA's precursor utilizing CO2 solvent as a cleaner solvent compared to conventional extraction method. The study assessed the effects of three extraction parameters, namely temperature (40–60 °C), pressure (15–35 MPa), and solvent flow rate (4–8 ml/min). The pressure, flowrate, and temperature were found to be the most significant parameters affecting the sCO2 extraction. Through Taguchi optimization, the optimal parameters were determined as 60 °C, 35 MPa, and 4 ml/min with the highest lipid yield of 46.74 wt%; above-average findings were reported. Furthermore, the pretreatment process involved significant effects such as crumpled and exhaustive structure, facilitating the efficient extraction of total lipids from the microalgae matrix. This study investigated the microstructure of microalgae biomatrix before and after extraction using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Fourier-transform infrared spectroscopy (FTIR) was utilized to assess the potential of the extracted material as a precursor for biodegradable plastic production, with a focus on reduced heavy metal content through inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis. The lipid extracted from Chlorella Vulgaris sp. microalgae was analysed using gas chromatography-mass spectrometry (GC-MS), identifying key constituents, including oleic acid (C18H34O2), n-Hexadecanoic acid (C16H32O2), and octadecanoic acid (C18H36O2), essential for polyhydroxyalkanoate (PHA) formation.

Chemical Characterization of Supercritical Fluid Extract (SFE) of Ailanthus excelsa and Estimation of Total Phenols and Flavonoids in SFE

Ailanthus excelsa which is usually called as tree of heaven is known to possess anti- fungal activity. The bio constituents such as flavonoids and phenols which are present in the leaves of Ailanthus excelsa is known to possess anti- bacterial, anti- fungal properties. This experiment was conducted to study the fungicidal activity of Ailanthus excelsa and its characeterization. Results revealed that the supercritical fluid extraction was effective at 60⁰C of temperature and 225 bar pressure with solvent flow rate of 5 g/min and caron di- oxide flow rate at 20 g/min. The GC-MS analysis showed that forty different constituents were present in the A. excelsa. Among which, Ricinoleic acid, Diethyl phthalate, 1.63 Hexadecanoic acid, methyl ester and 9- octadecenoic acid (Z)-, methyl ester were found to impart anti- fungal activity. The total phenols and flavonoids was 19.65 mgGAEg-1 and 40.68 mgGAEg-1 respectively was found in the SFE extract of A. excelsa.

High-Speed Schlieren Imaging of Vapor Formation in Electrospray Plume.

Previous mechanistic descriptions of electrosprays mostly focused on the dynamics of Taylor cones, initial droplets, and progeny droplets. However, vapor formation during droplet desolvation in an electrospray plume has not been discussed to a great extent. Here, we implement a double-pass on-axis schlieren high-speed imaging system to observe generation and propagation of vapors in an offline electrospray source under different conditions. Switching between turbulent and laminar vapor flow was observed for all of the scanned conditions, which may be attributed to randomly occurring disturbances in the sample flow inside the electrospray emitter. Calculation of mean vapor flow velocity and analysis of vapor flow patterns were performed using in-house developed image processing programs. Experiments performed at different electrospray voltages (0-6 kV), solvent flow rates (100-600 μL min-1), and methanol concentrations (50-100%), indicate only a weak dependency between electrospray voltage and mean vapor velocity, implying that the vapor is mostly neutral; thus, the vapor is not accelerated by electric field. On the other hand, electrospraying solutions of analytes (with mass 151 Da or 12 kDa) did not remarkably increase the overall vapor flow velocity. The source of vapor's velocity is attributed to the inertia of the electrospray droplets. Although there are some differences between a modern electrospray ionization (ESI) setup and the setup used in our experiment (e.g., using a higher flow rate and larger emitter), we believe the findings of our study can be projected to a modern ESI setup.