Increase In Mass Transfer Rate Research Articles

A novel leaf bionic flow field with structured multi-level channel based on Murray's law in proton exchange membrane fuel cell for enhanced mass transfer

The design of flow field has a significant impact on the performance of proton exchange membrane fuel cells (PEMFCs). In this study, a novel leaf bionic flow field is designed and optimized based on Murray's law. The power consumption ratio is first used in the bionic PEMFC. Additionally, an evaluation criterion, the mass transfer efficiency evaluation criterion (MTEEC), is proposed to characterize mass transfer efficiency, and field synergy theory is used to analyze performance differences in mass transfer among various flow fields. The results demonstrate that adding multi-level channel and obstacles in the flow field significantly enhances cell output performance and reduces voltage losses in mass transfer regions. Applying Murray's law to distribute multi-level channel improves the uniformity of oxygen concentration distribution in the flow field and alleviates under-rib water accumulation. Compared to the secondary stream flow field (SSFF), the structure mesh of leaf bionic flow field (SMLBFF) demonstrates a nearly 19% increase in current density output at 0.45 V. SMLBFF exhibits an 81.51% increase in convective mass transfer rate compared to SSFF at 0.4 V. Moreover, the MTEEC of SMLBFF shows improvements of 179.68% at 0.5 A/cm2 and 135.43% at 1.0 A/cm2, compared to SSFF.

Three-dimensional porous SiC/BDD electrode with long-term robustness and enhanced electrochemical degradation performance for refractory organic pollutants

Boron-doped diamond (BDD) electrodes with a three-dimensional (3D) porous network structure can overcome the mass transfer limitations and increase substantially the utilization rate of active oxygen species. Nonetheless, the 3D porous network structure was invariably built using metallic substrates, which inherently have inferior stability because of their non-corrosion resistance and the severe thermal mismatch between BDD films and substrates. Herein, we reported, for the first time, the use of a commercially porous silicon carbide (SiC) as the substrate to construct a 3D SiC/BDD electrode to simultaneously alleviate the problematics of substrate corrosion and thermal mismatch. This novel electrode exhibited a long-term service lifetime of 800 h in 3 M H2SO4 under the current density of 50 mA cm−2, over 500 times longer than the conventional metallic substrate-based BDD electrodes. The optimum p-SiC/BDD electrode exhibited a high oxygen evolution potential of 2.04 V vs. SHE, a low charge transfer resistance of 18.4 Ω, a high mass transfer coefficient of 2.78 × 10−5 m s−1, and a thin diffusion layer thickness of 25.2 μm. The proposed electrode had a threefold larger pseudo-first-order reaction rate constant than a flat BDD electrode, although it consumed just a fourth of the latter’s electric energy. The superior performance was attributable to an increased mass transfer rate confirmed by computational fluid dynamics (CFD) simulations as well as a high yield of reactive oxygen species verified by electron spin resonance (ESR). Furthermore, the proposed SiC/BDD electrode could work effectively under different water matrices in the presence of diverse salt electrolytes, thus paving a new avenue for the structure design of robust non-active anode materials.

Ancient Nova Shells of RX Pup Indicate Evolution of Mass Transfer Rate

RX Pup is a symbiotic binary that experienced a nova outburst in the 1970s. Here we report a discovery of a ∼1300 yr old nova shell around the system and a possible detection of a ∼7000 yr old nova shell. Together with the nova shell ejected in the 1970s, this makes RX Pup the first system with three nova shells observed. This triad of eruptions suggests a change in the nova recurrence time. The most likely explanation is an alteration in the mass transfer rate attributed to evolutionary changes of the mass donor in the system. Notably, comparative analyses with theoretical models indicate an increase in the average mass transfer rate by a factor of 3 over the past 10,000 yr. This makes RX Pup a unique system, which allows us to probe millennium-scale evolution of mass transfer rates in binary systems.

Improving Electrical Conductivity of LiFePO4 through Advanced Synthesis and Multidoping Techniques

Extensive research has been conducted to enhance the electrical conductivity of LiFePO4. Several techniques, including doping with metal cations, synthesizing nanocrystalline grains, and carbon coating, have been employed [1]. Recent advances in material synthesis have revolutionized LiFePO4, such as depositing conductive carbon coatings on active material particles and exploring surface doping techniques. These advanced approaches have significantly improved the mass transfer rate [2]. High-capacity LiFePO4 materials close to the theoretical specific capacitance have been obtained.Efforts are currently underway to improve the electronic and ionic conductivity of LiFePO4 to enhance its efficiency. However, before it can be widely used, the material's low electronic conductivity and suboptimal performance in high-speed regimes must be overcome. Doping with supervalent cations is an effective method for narrowing the energy gap and increasing the electrical conductivity of LiFePO4 [3]. Additionally, the synthesis of nanocrystalline grains and the deposition of conductive carbon coatings on the particle surface contribute to an increase in mass transfer rate, removing critical performance limitations of LiFePO4. Reducing the size of LiFePO4 to the nanoscale has been identified as a strategic method to shorten the diffusion length of Li-ions and accelerate electron-conducting pathways during charging and discharging cycles, ultimately improving the overall performance of the material.This work compares the doping process of LiFePO4 cathode material using two methods: solid-phase synthesis in a planetary ball mill and spray pyrolysis in an inert gas atmosphere. The studies on the synthesis and modification of LiFePO4 have significant potential to overcome existing limitations and unlock its full potential for integration into high energy density batteries. The above multidoping methods enable the production of doped LiFePO4 materials with specific capacitance approaching theoretical values. Acknowledgments This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP19677233).

Experimental study of solute diffusion in oscillating flow in a rectangular cell

Abstract The mass transfer of a passive substance dissolved in a fluid in a rectangular Hele–Shaw cell is experimentally studied. We consider mass transfer when the fluid is (i) at rest and (ii) oscillates. In the first case, mass transfer is carried out due to molecular diffusion. The results of measuring the molecular diffusion coefficient of the fluorescent dye Rhodamine B in water are in good agreement with the data obtained by other methods. In the presence of oscillations, the mass transfer rate increases. The comparison of the obtained experimental results with theoretical predictions reveals that the mass transfer is enhanced due to the Taylor dispersion.

CFD–PBM coupled modeling of liquid–liquid interphase mass transfer behaviors inside the Kenics static mixer

Kenics static mixers (KSM) are commonly used in various industries for its excellent mass transfer performance. It is essential to systematically analyze the relationship between fluid parameters and mass transfer parameters to better understand the mass transfer behaviors between liquid–liquid phases and optimize the mass transfer efficiency of the KSM. In this work, a computational fluid dynamic–population balance model coupled method is utilized and three mass transfer models are compared and analyzed. Further simulations investigate the mass transfer behaviors inside the KSM under different superficial velocities, dispersed phase volume fractions, and aspect ratios. The results show that the increase of superficial velocity leads to the 2.23–14.15–fold increase of volumetric mass transfer coefficient and the 1.71–4.56–fold increase of mass transfer rate. What's more, increasing the dispersed phase volume fraction leads to the significant increase of 15.51 times in volumetric mass transfer coefficient and 34.92 times in mass transfer rate. Moreover, the increase of aspect ratio could result in the reduction of 4.19–1.72 times in volumetric mass transfer coefficient and 1.81–1.17 times in mass transfer rate. This work provides valuable theoretical insights for the optimal design of the KSM and the enhancement of mass transfer performance.

Unsteady MHD‐radiative thin film flow with heat transfer over a stretching surface in porous media

AbstractThis study conducts a computational analysis to explore how magnetic fields, radiation, heat, and mass transfer collectively influence a horizontal stretching sheet within a porous medium. The research focuses on elucidating the dynamics of thin film flow through the formulation of time‐dependent equations and subsequent transformation of fluid flow equations into ordinary differential equations via similarity transformation. The numerical solution is attained employing the Runge–Kutta fourth‐order method coupled with a shooting technique. MATLAB software is utilized to generate graphs and numerical values, offering a detailed representation of engineering‐relevant physical quantities in tabular form. The investigation revealed notable trends associated with varying parameters. Increasing unsteadiness parameters lead to a reduction in velocity, temperature, and concentration fields, while the temperature distribution demonstrates a positive correlation with radiation parameters. Moreover, elevated Prandtl numbers and unsteadiness parameters correspond to augmented heat and mass flux, respectively. Of particular significance is the observed heightened heat transfer rate during the transition from a Prandtl number of 1 (representing air) to 2 (representing oil), alongside an increased mass transfer rate with the escalation in Schmidt number from 0.62 (representing hydrogen) to 0.78 (representing ammonia). A comparative analysis of the numerical findings with existing literature demonstrates excellent agreement, affirming the validity and relevance of the present study. These insights offer valuable implications for understanding and optimizing heat and mass transfer processes in porous media, with potential applications in various engineering and scientific domains.

Preparation of porous materials by ultrasound-intensified acid leaching of high-carbon component in coal gasification fine slag

Coal gasification fine slag is one of the by-products from clean and efficient utilization of coal, and its resource utilization is extremely urgent. In this work, a high carbon fraction with a fixed carbon content higher than 60% was obtained by simple sieving of gasification fine slag, from which a porous material was prepared by ultrasonic acid leaching method. The adsorption performance of porous materials, being used as treatment of radioactive iodine in nuclear wastewater, is characterized by iodine adsorption value. The effects of ultrasound time, ultrasound power, acid concentration, and temperature on the iodine adsorption performance and compositional structure of the porous materials were systematically investigated by combining the results of SEM, BET, XRD, and FT-IR. The mechanisms of ultrasound-enhanced acid leaching on compositional structure of residual carbon and migration and transformation laws of the ash constituents were explored and summarized. The results show that the porous material prepared under conditions of acid concentration of 4 mol/L, acid immersion temperature of 50 °C, ultrasonic power of 210 W, and ultrasonic time of 1.5 h has the best iodine adsorption performance of 468.53 mg/g, with a specific surface area of 474.97 m2/g, and possesses a rich pore structure with predominant mesopores. The order of each factor on the iodine adsorption performance is: sonication time > acid concentration > sonication power > acid immersion temperature. The mechanism of ultrasonic enhanced acid leaching is that ultrasonic cavitation and mechanical wave action firstly enhance dissociation of carbon-ash adherent particles, thus making desorption of ash particles blocked in pore channels of the gasification slag to increase its connectivity; secondly, lead to generation of cracks on surface of the carbon and ash particles to enhance accessibility of inorganic components inside the carbon particles; and thirdly, enhance the acid leaching process by increasing mass transfer rate to strengthen leaching effect of inorganic components in the gasification slag.

Enhanced treatment of p-nitrophenol and coking wastewater through electrochemical and electrochemical-ozonation coupling process utilizing a novel Ti4O7 reactive electrochemical membrane anode

Organic pollutants in water could be removed by electrochemical treatment using a reactive electrochemical membrane (REM) with Magnéli phase Ti4O7, yet it is challenging to design suitable porosity to realize effective mass transfer and enhance the reactivity. Here, a novel Ti4O7 REM was prepared by a spark plasma sintering (SPS) method, which showed excellent electrochemical reactivity and mass transfer rate for organic pollutants in water. Compared to other Ti4O7 REMs, the novel Ti4O7 REM achieved a 140–9000-fold decrease in charge transfer resistance and a 5–110-fold increase in mass transfer rate. The p-nitrophenol in water can be completely removed in the REM system, with a maximum total organic carbon (TOC) removal rate of 85%. Then the REM system obtained an amazing removal rate of TOC (50.1%) and UV254 (89.6%) in the electrochemical treatment of real coking wastewater. In addition, to further enhance the removal efficiency, a coupled oxidation process with the novel Ti4O7 REM and O3 aeration was investigated. The TOC removal rate and energy consumption were 57.1% and 165.2 kWh (kg TOC)−1 at the optimal conditions within a short treating time. Our findings highlighted an innovative REM for a broad range of potential environmental applications.

Influence of Joule heating and magneto-hydrodynamic on double diffusion mixed convection in a cavity with liquid sodium-potassium alloy and discrete thermosolutal source

Researchers in the biomedical field have focused more on the application of magneto-hydrodynamics in recent years. This study examines the steady double-diffusive mixed convection characteristics in a double-sided cavity with liquid potassium alloy that exhibits a magnetic effect and Joule heating. The investigation analyzes the impact of various parameters, including Hartmann number (0 ≤ Ha ≤ 50), Joule Heating (0 ≤ J ≤ 10.0), Reynolds number (102 ≤ Re ≤ 103), Lewis number (1.0 ≤ Le ≤ 10.0), Buoyancy ratio (−4.0 ≤ N ≤ 4.0), Prandtl number (Pr = 0.054), and Richardson Number (Ri = 1.0). The results are obtained using finite volume-based numerical codes. The findings suggest that the heat and mass transfer rates increase as Re and J increase and decrease when there is an increase in Ha and N. There is a significant effect on both the Joule parameter and magnetic field on fluid and heat flow. When Joule heating is present, increasing the Le results in a 0.627 times increase in heat transfer rate and a 1.722 times increase in mass transfer rate. When Re increases, the average Nusselt number (Nuavg) and average Sherwood number (Shavg) increase 0.81 and 0.11 times, respectively.

Mechanism of pH Effect on Mass Transfer During Bubble Evolution on Photoelectrode Surfaces

This study conducted in-depth research on the limitation problem of mass transfer of gas molecules on the surface of the photoelectrode to the efficiency of photoelectrochemical water splitting. Experimental results reveal significant differences in the dynamic characteristics of bubbles and mass transfer mechanisms during bubble growth under different pH conditions. As the pH deviates from 7.0 (vs RHE), the reaction rate increases, the bubble nucleation voltage decreases, and the terminal rising velocity increases significantly. During the rapid growth phase of bubbles, the mass transfer coefficient reaches its peak, accounting for only 1% of the entire evolution cycle. In a neutral environment (pH = 7.0), the transient mass transfer coefficient reaches a maximum at approximately 1 s of bubble growth, while in an alkaline environment (pH = 12.0), it reaches a maximum at around 0.1 s. In strongly alkaline environments (pH = 13.0), the PEC reaction rate and mass transfer rate increase, resulting in the highest gas production efficiency. The mass transfer coefficients were improved by about 72.4% and 42.8% (vs Ag/AgCl) and by about 22.2% and 33.3% (vs RHE) in the strong alkaline environment relative to the strong acid environment (pH = 1.0) and the neutral environment, respectively.

Electrochemical detoxification of tetrabromobisphenol A-contaminated water using Ti/SnO2-Sb/PbO2-Ce anodic membrane

Degradation of refractory organics has been limited by their low mass-transport rates in conventional flow-by operated electrochemical reactors. This study explores for the first time the development of porous titanium (Ti)-based metal oxide anodic membrane for efficient flow-through degradation of recalcitrant tetrabromobisphenol A (TBBPA). For this purpose, a duplexed Ti/SnO2-Sb/PbO2-Ce anodic membrane was successfully prepared by sol-gel and electrodeposition methods. Ti/SnO2-Sb/PbO2-Ce exhibited improved mechanical and electrochemical stability, larger electrochemical surface area, higher oxygen evolution potential and lower charge transfer resistance, as compared to its mono-layered rival (Ti/SnO2-Sb). The switching from flow-by to flow-through operation resulted in an increased mass transfer rate constant and narrowed diffusion layer thickness of Ti/SnO2-Sb/PbO2-Ce. In the flow-through mode, Ti/SnO2-Sb/PbO2-Ce enabled the complete TBBPA removal at a relatively low electric energy (0.11 kWh m−3). The TBBPA removal was ascribed to the direct anodic oxidation and indirect anodic oxidation incurred by absorbed HO, free HO and 1O2. The intermediate products, which were arisen from the attack of TBBPA by these reactive species, were identified. We further estimated their acute toxicities and bioaccumulation factors. This research proposed a robust electrochemical filtration approach for detoxification of TBBPA-contaminated water.

The Application of Microfibrous Entrapped Activated Carbon Composite Material for the Sarin Simulant Dimethyl Methylphosphonate Adsorption.

Granular activated carbon (GAC) has proven to be an effective adsorbent for removing the chemical warfare agent sarin (GB) and simulants like Dimethyl methylphosphonate (DMMP). However, it comes with certain limitations, including inadequate contact efficiency, notable mass transfer resistance, and lower bed utilization efficiency. This study synthesized steel fiber-entrapped activated carbon composites (SFEACs), which exhibited a maximum adsorption capacity of 285.3 mg/g at 303 K. Compared with the packed bed (PB) filled with GAC, while the adsorption capacity of SFEACS decreased, there was a substantial increase in the adsorption mass transfer rate. These SFEACs were combined with GAC to create a structural fixed bed (SFB), which demonstrated excellent performance in DMMP removal. Under identical experimental conditions, the DMMP breakthrough curve of SFB exhibited a steeper profile compared to the packed bed (PB) filled with GAC at the same bed height, and the breakthrough time against DMMP vapor could be extended by 13.8%. Furthermore, the adsorption rate constant of the Yoon-Nelson model increased by more than 17.6%, and the unused bed length, according to the Wheeler-Jonas model, decreased by more than 14%.

Mathematical modeling and simulation of oxygen mass transfer in rotating biological contactor (RBC) for bacterial cellulose production

The Rotary Biological Contact (RBC) reactor has a unique aeration system that provides a moving bed for easy and efficient oxygen transfer within the system to overcome the limitations of stationary culture in bacterial cellulose (BC) production. In most cases, oxygen mass transfer is the limiting factor of an aerobic process, hence the changes in the oxygen mass transfer coefficient within the system have been given special attention. In this study, the RBC bioreactor producing BC was modeled based on one-dimensional oxygen mass transfer in the direction perpendicular to the surface of the discs. The Monod kinetic model has been used to express cell growth. Simulation of the mathematical model was done based on the numerical solution with finite difference method in MATLAB software. Sensitivity analysis was performed to investigate the effect of changing different system parameters in RBC modeling. The simulation results showed that with the increase in angular velocity, the oxygen transfer coefficient and subsequently the mass transfer rate increase. Also, at a certain angular velocity, the oxygen mass transfer coefficient increases with the increase of immersion depth. The best disk rotation speed considering other parameters as well as the laboratory results was 13 rpm with a 45% indentation percentage and the optimal distance between the disks was 1.5 cm.

Enhancing the parboiling of pantanal rice with ultrasound-assisted hydration: Mass transfer kinetics and bioactive properties

We evaluated the effects of ultrasound-assisted hydration (UH) on process time and concentration of phenolic compounds during the parboiling of native Pantanal paddy rice (Oryza latifolia) in comparison to conventional hydration (CH). This rice variety is produced by indigenous and riverside communities in the Pantanal biome. The UH increased water absorption, with a 58% average reduction in process time. Irreversible changes in the physical structure of rice (visible to the naked eye and in electronic microscopy images) confirmed that the grains parboiled faster. The Peleg model satisfactorily predicted the moisture uptake experimental data (R2 > 0.94). The CH significantly reduced the concentration of total phenolic compounds (TPC) (16–19%), total flavonoids (TF) (30–40%), and antioxidant capacity (AA) (20–39%) of paddy rice hydrated at 65–75 °C. In turn, the UH caused minimal loss of TPC (<1%), lower reduction of TF (∼7%) and AA (4–12%). The results indicate that ultrasound enhances parboiling processes by increasing mass transfer rates during hydration, consequently shortening processing time, reducing the energy demand, and preserving the nutritional quality of rice. The preservation of phenolic compounds during parboiling via ultrasound-assisted hydration (UH) is notable because the significant loss of these compounds in conventional hydration (CH). Therefore, parboiled rice falls short of being classified as a functional food. By preserving the phytochemicals during parboiling, the proposed process here may contribute to classifying Pantanal rice as a functional food, enabling income generation for local communities through the commercialization of parboiled native rice.

Recent Progress and Application of Freeze Dryers for Agricultural Product Drying

AbstractThe impact of various freeze‐drying (FD) methods on the drying efficiency and quality of dried fruits and vegetables is reviewed. Additionally, a brief overview of recent advances in FD methods is provided. The FD technique is characterized by the following key properties: ability to maintain original texture and color, the highest nutritional value, and appropriate rehydration rate due to the porous tissue of the product. Recently, various combination methods have been tested to improve the drying speed and save energy when FD fruits and vegetables. This includes combining FD systems with other techniques such as ultrasound, microwave, vacuum, infrared radiation, pulsed electric field (PEF), and CO2 laser perforation. Combined benefits of these technologies include increased mass transfer rates, shorter dehydration time, energy savings, improved product quality, lower shrinkage, higher rehydration capacity, and flexibility to dry and manufacture the many types of dried fruits and vegetables pieces.

Zeolite-coated fin–coil heat exchanger for CO2 recovery from simulated dry flue gas via low-temperature-heat-driven TSA

Adsorbent-coated heat exchangers are expected to achieve not only high adsorption and desorption rates based on the rapid heat transfer in their adsorbent layers but also a low pressure drop owing to their structured adsorbent layers. In this study, a CaA-zeolite-coated adsorber was experimentally investigated to improve the CO2 capture performance of low-temperature-heat-driven temperature swing adsorption (TSA) from dry flue gas, a major source of greenhouse gas emissions. At a feed CO2 concentration of approximately 10 vol%, a flow rate of 1 L-STP/min, and a temperature swing range of 20 °C–80 °C, the performance of the coated adsorbent was first compared with that of a heat exchanger of a similar volume packed with CaA zeolite pellets. Due to the enhancement in heat transfer of the coated adsorbent, almost the same CO2 concentration and a higher CO2 recovery ratio as those of the packed adsorbent were obtained at an appropriate cycle time despite that the amount of coated adsorbent was only one-third that of the packed adsorbent. Therefore, the accelerated heat transfer in the adsorbent layer significantly affected the increased mass transfer rate in or around the coated adsorbent. Next, the effect of the space velocity (SV) was investigated using a coated heat exchanger that had a three-times-longer length in the gas flow direction and approximately the same thickness of the adsorbent coating layer as the above coated heat exchanger. Although a separate discussion on the larger adsorber size is necessary, the CO2 recovery concentration was over 50% and the recovery ratio exceeded 80% as the SV was reduced by one-third. Furthermore, the fin pitch of the heat exchanger was doubled and the thickness of the adsorbent coating was doubled while maintaining the same volume of the heat exchanger and the same amount of adsorbent coating. This was done to reduce the heat capacity of the heat exchanger, which is a factor in heat loss in TSA, by reducing the number of fins used. The doubled adsorbent coating layer thickness and halved contact area with the gas flow resulted in a decrease in CO2 capture. Thus, the effects of an increased adsorbent layer thickness and a reduced contact area should be determined to further increase the effectiveness of the adsorbent-coated heat exchangers.

Influence of throat and diverging section on the performance of venturi scrubber by using computational fluid dynamics

Filtered Containment Venting System (FCVS) is a safety system of nuclear power plants whose primary objectives are control of over-pressurization and prevention of release of radioactivity in severe accidents. In a severe accident scenario, when pressure of containment exceeds a set limit, this system gets activated and part of containment steam/gases mixture is transferred to FCVS where removal of hazardous radioactive gases like iodine takes place via scrubbers and then cleaner air is vented out. Iodine removal is necessary because if discharged into environment, it can cause serious health concerns including thyroid cancer. Venturi scrubbers are a key component in FCVS for retention of iodine. Research on various parameters of venturi scrubbers is necessary in order to attain maximum removal efficiency. This research was carried out to investigate the effect of geometric parameters of venturi scrubber on iodine removal using Computational Fluid Dynamics. Parameters such as number of orifices, diameter and length of diverging section and length and diameter of throat section were studied. Influence of variation in above-mentioned geometric parameters on different operational parameters like pressure, volume fraction phase-1, velocity, mass transfer rate and iodine mass fraction was investigated. Order of effect of geometric parameters on iodine removal from lower to higher comes out to be diverging diameter, diverging length, throat length, number of orifices, and throat diameter. 5–68% increase in mass transfer rate was observed from variation in parameters. This research would be very helpful for researchers and designers in parametric optimization and design of an efficient venturi scrubber.

An optimization method for enhancement of gas–liquid mass transfer in a bubble column reactor based on the entropy generation extremum principle

In this study, an optimization method is proposed to enhance the gas–liquid mass transfer in bubble column reactor based on the entropy generation extremum principle. The mass transfer- induced entropy generation can be maximized with the increase of mass transfer rate, based on which the velocity field can be optimized. The oxygen gas–liquid mass transfer is the major rate-limiting step of the toluene emissions biodegradation process in bubble column reactor, so the entropy generation due to oxygen mass transfer is used as the objective function, and the conservation equations of the gas–liquid flow and species concentration are taken as constraints. This optimization problem is solved by the calculus of variations, the optimal liquid flow pattern is obtained and the relationship of the maximum mass transfer enhancement on viscous dissipation is revealed, which can be used to improve the design of internal structure of the bubble column reactor.

Testing of a new high voltage electrical discharge generator prototype at high frequencies to assist anthocyanin extraction from blueberries

Traditional extraction methods are based on high-temperature maceration with organic solvents, which are dangerous for human health. A viable alternative to overcome the issues associated with conventional extraction is to increase cell tissue permeability by applying high voltage electrical discharge (HVED) treatments. The objective of this work was to validate the electroporation of blueberry plant cells using a new HVED generator prototype at a high frequency, investigate the effect, intensity, and duration of the applied voltage, and recover anthocyanins from its electroporated cells. The electroporation level of the HVED-treated blueberries was measured qualitatively by transmission electron microscopy (TEM) analysis. Meanwhile, it was quantitatively measured by the cell permeabilization index (Zp) and anthocyanin extraction level. Results of the micrographs (TEM) showed electroporation in all treatments in which Zp was 0.24 when applying a 2 kV treatment for 2 s, whereas a 3-fold increase in tissue damage was revealed with the most powerful treatment (10 kV voltage, 30 s). In addition, anthocyanin values ranged from 83.09 ± 1.20 (control) to 136.82 ± 0.84 (HVED), which was 64.66% higher. The HVED treatment can increase mass transfer rates during conventional extraction processes. It should be noted that the validated prototype required a low specific energy requirement (31–204 kJ/kg) for proper tissue electropermeabilization. In conclusion, we demonstrated the capability of the developed HVED prototype to boost mass transfer phenomena and thus potentially increase its adaptability to assist dissimilar industrial processes or waste (e.g., peels and seeds) such as freeze-drying operations.