Pub Date : 2025-09-01DOI: 10.1016/j.elstat.2025.104075
Alex Martynenko
Electrohydrodynamics (EHD) is an interdisciplinary field that combines electrodynamics and fluid dynamics, primarily studying fluid motion driven by electric fields. The mechanisms of EHD arise from the interaction between the electric fields, charged particles and polarization effects within the fluid. This review extends the boundaries of our knowledge about mechanisms of EHD-induced mass transfer. The impact of EHD flow on convective and diffusive mass transfer in gaseous and liquid phases of capillary-porous materials is thoroughly discussed. The review covers the gap between electrohydrodynamics and thermodynamics, serving as a reference for future EHD applications in mass transfer processes.
{"title":"EHD-induced mass transfer from wet materials","authors":"Alex Martynenko","doi":"10.1016/j.elstat.2025.104075","DOIUrl":"10.1016/j.elstat.2025.104075","url":null,"abstract":"<div><div>Electrohydrodynamics (EHD) is an interdisciplinary field that combines electrodynamics and fluid dynamics, primarily studying fluid motion driven by electric fields. The mechanisms of EHD arise from the interaction between the electric fields, charged particles and polarization effects within the fluid. This review extends the boundaries of our knowledge about mechanisms of EHD-induced mass transfer. The impact of EHD flow on convective and diffusive mass transfer in gaseous and liquid phases of capillary-porous materials is thoroughly discussed. The review covers the gap between electrohydrodynamics and thermodynamics, serving as a reference for future EHD applications in mass transfer processes.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"137 ","pages":"Article 104075"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrohydrodynamics (EHD) explores the interactions between electric fields and various fluid media. The core principle of electrically driven fluid motion lies in the direct conversion of electrical energy into fluid kinetic energy, forming the basis for efficient and intelligent energy utilization. Among the fundamental topics in EHD, Coulomb-force-driven electro-convection (EC) plays a crucial role in understanding the interaction mechanisms between flow fields and electric fields, as well as charge transport processes. Building upon EC, electro–thermo-convection (ETC) introduces additional complexity by incorporating nonlinear interactions among the temperature field, electric field, flow field, and charge density field. This leads to rich nonlinear bifurcation phenomena and provides new theoretical insights for applications such as heat transfer enhancement and intelligent thermal management. This study systematically examines the behavior and underlying mechanisms of EC and ETC in square cavities, parallel plates, and annular geometries. It focuses on charge generation mechanisms, the dimensionless formulation of governing equations, and key control parameters, while also analyzing the nonlinear interactions in EC and ETC and their impact on flow stability and heat transfer efficiency.
{"title":"Review on electro-convection and electro–thermo-convection in dielectric liquids within different geometrical models","authors":"Guangze Liu, Yu Zhang, Dian Li, Yuxing Peng, Jian Wu","doi":"10.1016/j.elstat.2025.104089","DOIUrl":"10.1016/j.elstat.2025.104089","url":null,"abstract":"<div><div>Electrohydrodynamics (EHD) explores the interactions between electric fields and various fluid media. The core principle of electrically driven fluid motion lies in the direct conversion of electrical energy into fluid kinetic energy, forming the basis for efficient and intelligent energy utilization. Among the fundamental topics in EHD, Coulomb-force-driven electro-convection (EC) plays a crucial role in understanding the interaction mechanisms between flow fields and electric fields, as well as charge transport processes. Building upon EC, electro–thermo-convection (ETC) introduces additional complexity by incorporating nonlinear interactions among the temperature field, electric field, flow field, and charge density field. This leads to rich nonlinear bifurcation phenomena and provides new theoretical insights for applications such as heat transfer enhancement and intelligent thermal management. This study systematically examines the behavior and underlying mechanisms of EC and ETC in square cavities, parallel plates, and annular geometries. It focuses on charge generation mechanisms, the dimensionless formulation of governing equations, and key control parameters, while also analyzing the nonlinear interactions in EC and ETC and their impact on flow stability and heat transfer efficiency.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"137 ","pages":"Article 104089"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrohydrodynamic flow, recognized as a promising active method with a wide range of applications, has been identified as a potential candidate for thermal management and the heat transfer enhancement. This review provides a comprehensive analysis of recent advancements in the EHD technique and its efficacy in enhancing convective heat transfer. Related literature published that examines the interaction between EHD flow and the convection heat transfer has been systematically classified and discussed. The conclusions of the studies indicate that EHD technology has the potential to serve as an effective approach to thermal management, particularly in terms of enhancing heat transfer efficiency and reducing power consumption. The impact of effective operational and geometric parameters on the EHD-enhancing heat transfer has been highlighted. In a word, this review aims to elucidate the opportunities arising from research on EHD heat transfer enhancement and to explore its future development trends.
{"title":"A review of recent advancements in electrohydrodynamic heat transfer enhancement","authors":"Nima Amanifard , Hesam Moayedi , Farid Dolati , Hamed Mohaddes Deylami","doi":"10.1016/j.elstat.2025.104151","DOIUrl":"10.1016/j.elstat.2025.104151","url":null,"abstract":"<div><div>Electrohydrodynamic flow, recognized as a promising active method with a wide range of applications, has been identified as a potential candidate for thermal management and the heat transfer enhancement. This review provides a comprehensive analysis of recent advancements in the EHD technique and its efficacy in enhancing convective heat transfer. Related literature published that examines the interaction between EHD flow and the convection heat transfer has been systematically classified and discussed. The conclusions of the studies indicate that EHD technology has the potential to serve as an effective approach to thermal management, particularly in terms of enhancing heat transfer efficiency and reducing power consumption. The impact of effective operational and geometric parameters on the EHD-enhancing heat transfer has been highlighted. In a word, this review aims to elucidate the opportunities arising from research on EHD heat transfer enhancement and to explore its future development trends.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"137 ","pages":"Article 104151"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.elstat.2025.104153
Alex Destrieux, Ramavtar Jangra, Karol Hensel, Zdenko Machala
According to World Health Organization, urban populations spend 90 % of their time in indoor environments. Accentuated by the recent COVID-19 pandemic, this raises important concerns about the quality of the indoor air, which often contains various types of contaminants within three main categories: biological, volatile organic compounds, and particulate matter. Several technologies already exist for removing contaminants from indoor air, such as electrostatic based methods or filtration. Although these technologies are well established, they often target only one or two groups of contaminants. This review focuses on a promising technology: nonthermal plasma combined with catalysts. After an overview of indoor air contaminants, their sources, and the typical methods used for their removal, a highlight is put on the available commercial indoor air purification devices. The latter are rarely described in literature, and the comparison with lab-scale experiments are difficult due to the lack of information and available data from the manufacturers. The limitations of those systems are also discussed. As most of these commercial devices use combinations of various conventional technologies, the last part focuses on the ongoing research on plasma-catalytic systems. The main mechanisms are presented along with recent literature. Finally, some perspectives for its future development are proposed.
{"title":"Review on scientific studies and commercial indoor air purification devices: Focus on plasma-catalytic technology","authors":"Alex Destrieux, Ramavtar Jangra, Karol Hensel, Zdenko Machala","doi":"10.1016/j.elstat.2025.104153","DOIUrl":"10.1016/j.elstat.2025.104153","url":null,"abstract":"<div><div>According to World Health Organization, urban populations spend 90 % of their time in indoor environments. Accentuated by the recent COVID-19 pandemic, this raises important concerns about the quality of the indoor air, which often contains various types of contaminants within three main categories: biological, volatile organic compounds, and particulate matter. Several technologies already exist for removing contaminants from indoor air, such as electrostatic based methods or filtration. Although these technologies are well established, they often target only one or two groups of contaminants. This review focuses on a promising technology: nonthermal plasma combined with catalysts. After an overview of indoor air contaminants, their sources, and the typical methods used for their removal, a highlight is put on the available commercial indoor air purification devices. The latter are rarely described in literature, and the comparison with lab-scale experiments are difficult due to the lack of information and available data from the manufacturers. The limitations of those systems are also discussed. As most of these commercial devices use combinations of various conventional technologies, the last part focuses on the ongoing research on plasma-catalytic systems. The main mechanisms are presented along with recent literature. Finally, some perspectives for its future development are proposed.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"137 ","pages":"Article 104153"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-28DOI: 10.1016/j.elstat.2025.104159
M.A. Sayoud, N. Zouzou
The effectiveness of filter media technique for air purification is no longer a matter of debate. However, the challenge now is to determine ways of optimizing particle-fiber interactions in order to achieve the optimal balance between particles collection efficiency and pressure drop across the filter. In this paper, we are particularly interested in interactions of an electrical nature, governed essentially by Coulomb, dielectrophoretic (DEP) and image forces. At first, we developed a special experimental protocol that enabled us to focus mainly on these interactions. Then, by controlling particle charge levels, we were able to dissociate the contribution of each force on collection efficiency and to explore parameters influencing them, such as particle and wire diameters, mesh size, inter-grid distance and electric field intensity within an Electric Metal Mesh Filter (EMMF). The results revealed that the contribution of Coulomb force to collection efficiency is the most important, particularly in the case of strong field and high charge level. The efficiency by DEP force increases with field intensity, particle diameter and decreasing fiber diameter, whereas the effect of inter-grid distance and mesh size were limited. As for image force, its impact on collection efficiency increases with particle charge, although it remains marginal.
{"title":"Effect of particle electrostatic charge level on collection efficiency of an electric metal mesh filter","authors":"M.A. Sayoud, N. Zouzou","doi":"10.1016/j.elstat.2025.104159","DOIUrl":"10.1016/j.elstat.2025.104159","url":null,"abstract":"<div><div>The effectiveness of filter media technique for air purification is no longer a matter of debate. However, the challenge now is to determine ways of optimizing particle-fiber interactions in order to achieve the optimal balance between particles collection efficiency and pressure drop across the filter. In this paper, we are particularly interested in interactions of an electrical nature, governed essentially by Coulomb, dielectrophoretic (DEP) and image forces. At first, we developed a special experimental protocol that enabled us to focus mainly on these interactions. Then, by controlling particle charge levels, we were able to dissociate the contribution of each force on collection efficiency and to explore parameters influencing them, such as particle and wire diameters, mesh size, inter-grid distance and electric field intensity within an Electric Metal Mesh Filter (EMMF). The results revealed that the contribution of Coulomb force to collection efficiency is the most important, particularly in the case of strong field and high charge level. The efficiency by DEP force increases with field intensity, particle diameter and decreasing fiber diameter, whereas the effect of inter-grid distance and mesh size were limited. As for image force, its impact on collection efficiency increases with particle charge, although it remains marginal.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"138 ","pages":"Article 104159"},"PeriodicalIF":2.1,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-28DOI: 10.1016/j.elstat.2025.104160
Thomas Vazquez , Aleksandra Lavrikova , Dalimír Wiedermann , Jan Babic , Miroslav Palko , Maroš Palko , Zdenko Machala
Advanced technology combining non-thermal plasma (NTP) with photocatalytic oxidation (PCO) for indoor air purification at high flow rates is tested on formaldehyde and bio-aerosol with E. coli bacteria. Two reactors were examined, both using TiO2 photocatalyst: reactor 1 with dielectric barrier discharge (DBD) tubes and UV-C, and reactor 2 with a DBD module and UV-A LEDs. The NTP-PCO significantly reduced formaldehyde using a single pass method with high 250 L/min air flow rate. The bioaerosol decontamination achieved 3 log reduction up to total bacteria inactivation. This proof-of-concept demonstrates a promising approach of the combined NTP-PCO for scalable indoor air purification.
{"title":"Non-thermal plasma coupled with photocatalysis for indoor air treatment at high air flow rates: effects on VOCs and bio-aerosols","authors":"Thomas Vazquez , Aleksandra Lavrikova , Dalimír Wiedermann , Jan Babic , Miroslav Palko , Maroš Palko , Zdenko Machala","doi":"10.1016/j.elstat.2025.104160","DOIUrl":"10.1016/j.elstat.2025.104160","url":null,"abstract":"<div><div>Advanced technology combining non-thermal plasma (NTP) with photocatalytic oxidation (PCO) for indoor air purification at high flow rates is tested on formaldehyde and bio-aerosol with <em>E. coli</em> bacteria. Two reactors were examined, both using TiO<sub>2</sub> photocatalyst: reactor 1 with dielectric barrier discharge (DBD) tubes and UV-C, and reactor 2 with a DBD module and UV-A LEDs. The NTP-PCO significantly reduced formaldehyde using a single pass method with high 250 L/min air flow rate. The bioaerosol decontamination achieved 3 log reduction up to total bacteria inactivation. This proof-of-concept demonstrates a promising approach of the combined NTP-PCO for scalable indoor air purification.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"138 ","pages":"Article 104160"},"PeriodicalIF":2.1,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Measuring the distribution of the electrical charges in various materials is of great importance for numerous industrial applications. The development of measurement method has been widely studied in the case of dielectric solids. However, for liquids, the development of measurement techniques is not as much established. Liquid materials, as for solid, are used in wide range of industrial applications, such as transformers or electrochemical energy storage. In order to determine the charge distribution within liquid materials, measurement technique used for solids have been adapt to be apply to liquids. The pulsed electro-acoustic (PEA) method has recently been adapted to liquids. It has been applied to various liquids under electrical constraints. Its application to liquids without electrical constraint, with the aim of measuring the natural distribution of electric charges (electrical double layer), is not widely done. This work proposes to apply the PEA method to various liquids without subjecting it to an electrical constraint, in order to assess its capability to measure the electrical double layer. The influence of different parameters on the response is presented and the trends obtained are compared with the trends expected from a theoretical model.
{"title":"Preliminary analysis of the electrical charge distribution within liquids using PEA","authors":"Matéo Dautremont , Paul Leblanc , Laurent Berquez , Thierry Paillat","doi":"10.1016/j.elstat.2025.104161","DOIUrl":"10.1016/j.elstat.2025.104161","url":null,"abstract":"<div><div>Measuring the distribution of the electrical charges in various materials is of great importance for numerous industrial applications. The development of measurement method has been widely studied in the case of dielectric solids. However, for liquids, the development of measurement techniques is not as much established. Liquid materials, as for solid, are used in wide range of industrial applications, such as transformers or electrochemical energy storage. In order to determine the charge distribution within liquid materials, measurement technique used for solids have been adapt to be apply to liquids. The pulsed electro-acoustic (PEA) method has recently been adapted to liquids. It has been applied to various liquids under electrical constraints. Its application to liquids without electrical constraint, with the aim of measuring the natural distribution of electric charges (electrical double layer), is not widely done. This work proposes to apply the PEA method to various liquids without subjecting it to an electrical constraint, in order to assess its capability to measure the electrical double layer. The influence of different parameters on the response is presented and the trends obtained are compared with the trends expected from a theoretical model.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"138 ","pages":"Article 104161"},"PeriodicalIF":2.1,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-28DOI: 10.1016/j.elstat.2025.104154
Giuseppe Andriani , Gianmaria Pio , Chiara Vianello , Paolo Mocellin , Ernesto Salzano
Early Warning Detection Systems (EWDS) are essential for preventing runaway reactions in chemical reactors by providing timely alerts before uncontrolled exothermic events. Conventional EWDS rely predominantly on temperature monitoring; however, industrial temperature sensors often suffer from delayed response and are highly dependent on sensor positioning, limiting their effectiveness during rapid or localized thermal excursions.
This study introduces an alternative detection strategy based on electrical conductivity monitoring, which offers faster response times and higher sensitivity—especially in reactions where ionic or charged species are released at the onset of runaway. A theoretical framework is presented to demonstrate how this method can overcome key limitations of temperature-based systems, enabling more accurate and responsive detection.
Compared to the benchmark divergence method, the conductivity-based approach detects runaway onset within 2 °C of the true temperature (vs. 3 °C deviation with temperature sensors), and anticipates the event 200–300 s before peak temperature. This allows earlier intervention and significantly reduces the maximum temperature rise at onset (by 30%–40% compared to temperature-based detection). Integrating advanced conductivity sensors into existing EWDS infrastructures could markedly improve reactor safety and control. This work lays the foundation for future experimental validation and broader adoption in chemical reaction engineering safety systems.
{"title":"Electrical conductivity as an indicator for early warning detection systems in chemical reactors","authors":"Giuseppe Andriani , Gianmaria Pio , Chiara Vianello , Paolo Mocellin , Ernesto Salzano","doi":"10.1016/j.elstat.2025.104154","DOIUrl":"10.1016/j.elstat.2025.104154","url":null,"abstract":"<div><div>Early Warning Detection Systems (EWDS) are essential for preventing runaway reactions in chemical reactors by providing timely alerts before uncontrolled exothermic events. Conventional EWDS rely predominantly on temperature monitoring; however, industrial temperature sensors often suffer from delayed response and are highly dependent on sensor positioning, limiting their effectiveness during rapid or localized thermal excursions.</div><div>This study introduces an alternative detection strategy based on electrical conductivity monitoring, which offers faster response times and higher sensitivity—especially in reactions where ionic or charged species are released at the onset of runaway. A theoretical framework is presented to demonstrate how this method can overcome key limitations of temperature-based systems, enabling more accurate and responsive detection.</div><div>Compared to the benchmark divergence method, the conductivity-based approach detects runaway onset within 2 °C of the true temperature (vs. <span><math><mo>∼</mo></math></span> 3 °C deviation with temperature sensors), and anticipates the event 200–300 s before peak temperature. This allows earlier intervention and significantly reduces the maximum temperature rise at onset (by 30%–40% compared to temperature-based detection). Integrating advanced conductivity sensors into existing EWDS infrastructures could markedly improve reactor safety and control. This work lays the foundation for future experimental validation and broader adoption in chemical reaction engineering safety systems.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"138 ","pages":"Article 104154"},"PeriodicalIF":2.1,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tribo-electrostatic separation is a simple, cost-effective, and environmentally friendly method to sort the different plastics contained in the ever-increasing quantities of waste electrical and electronic equipment (WEEE) accumulated all over the world and needing recycling. Among the various plastics found in WEEE, Acrylonitrile Butadiene Styrene (ABS) and Polystyrene (PS) are the most prevalent due to their excellent insulating and mechanical properties, making them essential in the electrical and electronic equipment (EEE) industry. However, their similar surface properties and close mass density values significantly limit wet separation methods, such as froth flotation and sink-float methods. Tribo-electrostatic separation was chosen over wet methods because it is a dry process that requires no chemical pretreatment, no expensive wetting reagents, while also eliminating wastewater treatment issues. This method exploits the differences in triboelectric properties of ABS and PS, enabling their separation without altering their chemical structure, which is critical for preserving recyclability. The aim of the present study was to evaluate the effects of several factors (moisture content, particle size, triboelectric charging conditions) that affect the efficiency of a two-stage tribo-electrostatic process employed for processing a mixture consisting of roughly 55 % Acrylonitrile Butadiene Styrene (ABS), 38 % Polystyrene (PS), and 7 % of other granular waste plastics. Heating the mixture significantly reduced the moisture content of the particles, which not only enhances the triboelectric charging efficiency but also considerably improved the outcome of the free-fall electrostatic separation process. The duration of the triboelectric charging process in a rotating-cylinder type device and the configuration of the electrode system that generates the electric field of the electrostatic separator are two other factors that influence the efficiency of the process. After the first stage of electrostatic separation, 74 % of the ABS particles were recovered in a 94 % pure product. Using a two-stage separation scheme, it was possible to recover 82 % of the PS, with a purity of 88 %. A fluidized bed triboelectric charger was found to be more efficient than the rotating-cylinder-type device. Under optimal operating conditions, the purity and recovery of ABS product increased to 97 % and 95 %, respectively.
{"title":"Influence of moisture content and triboelectric charging conditions on the tribo-electrostatic separation of actual granular mixtures of waste plastics","authors":"Siham Labiod , Mohamed Sofiane Bendilmi , Khaled Daioui , Thami Zeghloul , Farida Tomasella , Lucian Dascalescu","doi":"10.1016/j.elstat.2025.104157","DOIUrl":"10.1016/j.elstat.2025.104157","url":null,"abstract":"<div><div>Tribo-electrostatic separation is a simple, cost-effective, and environmentally friendly method to sort the different plastics contained in the ever-increasing quantities of waste electrical and electronic equipment (WEEE) accumulated all over the world and needing recycling. Among the various plastics found in WEEE, Acrylonitrile Butadiene Styrene (ABS) and Polystyrene (PS) are the most prevalent due to their excellent insulating and mechanical properties, making them essential in the electrical and electronic equipment (EEE) industry. However, their similar surface properties and close mass density values significantly limit wet separation methods, such as froth flotation and sink-float methods. Tribo-electrostatic separation was chosen over wet methods because it is a dry process that requires no chemical pretreatment, no expensive wetting reagents, while also eliminating wastewater treatment issues. This method exploits the differences in triboelectric properties of ABS and PS, enabling their separation without altering their chemical structure, which is critical for preserving recyclability. The aim of the present study was to evaluate the effects of several factors (moisture content, particle size, triboelectric charging conditions) that affect the efficiency of a two-stage tribo-electrostatic process employed for processing a mixture consisting of roughly 55 % Acrylonitrile Butadiene Styrene (ABS), 38 % Polystyrene (PS), and 7 % of other granular waste plastics. Heating the mixture significantly reduced the moisture content of the particles, which not only enhances the triboelectric charging efficiency but also considerably improved the outcome of the free-fall electrostatic separation process. The duration of the triboelectric charging process in a rotating-cylinder type device and the configuration of the electrode system that generates the electric field of the electrostatic separator are two other factors that influence the efficiency of the process. After the first stage of electrostatic separation, 74 % of the ABS particles were recovered in a 94 % pure product. Using a two-stage separation scheme, it was possible to recover 82 % of the PS, with a purity of 88 %. A fluidized bed triboelectric charger was found to be more efficient than the rotating-cylinder-type device. Under optimal operating conditions, the purity and recovery of ABS product increased to 97 % and 95 %, respectively.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"138 ","pages":"Article 104157"},"PeriodicalIF":2.1,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-16DOI: 10.1016/j.elstat.2025.104156
Ali Khoshnejad, Sohrab Gholamhosein Pouryoussefi, Alireza Doostmahmudi, Reza Ebrahimi
This study experimentally investigates the effects of multiple parallel dielectric barrier discharge (DBD) plasma actuators on controlling the flow separation in an S-shaped duct with an elliptical inlet and circular outlet. An open-loop suction-type test rig composed of composite materials was designed for this purpose. The synergistic effects of multiple DBD plasma actuators (MDBD) were initially examined on a flat plate before being applied to the complex geometry of the S-shaped duct. Additionally, the impact of varying plasma applied voltages (6, 6.5, 7, 7.5, 8 kV) and S-duct inlet velocities (24, 35, and 47 m/s) on the performance of the plasma actuators were investigated. Also, the pressure coefficient distribution on the lower surface of the duct was measured under various conditions. The use of MDBD plasma actuators on a flat plate resulted in a significant increase in the maximum induced velocity, approximately 50 % higher than that achieved with a single actuator. This enhancement is attributed to the synergistic effects of the multiple actuators on the induced flow. The application of the MDBD plasma actuator configuration within the S-shaped duct effectively delayed flow separation across all tested inlet velocities (Reynolds numbers of 2.35 × 105, 3.51 × 105, and 4.75 × 105). However, actuator effectiveness decreased with increasing inlet velocity. Higher actuation voltages resulted in a more pronounced delay in separation. Also, at a Reynolds number of 2.35 × 105, the MDBD configuration with 8 kV and 15 Hz achieved a 35.9 % increase in the pressure coefficient compared to the no-plasma condition.
{"title":"Experimental investigation of flow separation delay in S-shaped duct using multiple dielectric barrier discharge plasma actuators","authors":"Ali Khoshnejad, Sohrab Gholamhosein Pouryoussefi, Alireza Doostmahmudi, Reza Ebrahimi","doi":"10.1016/j.elstat.2025.104156","DOIUrl":"10.1016/j.elstat.2025.104156","url":null,"abstract":"<div><div>This study experimentally investigates the effects of multiple parallel dielectric barrier discharge (DBD) plasma actuators on controlling the flow separation in an S-shaped duct with an elliptical inlet and circular outlet. An open-loop suction-type test rig composed of composite materials was designed for this purpose. The synergistic effects of multiple DBD plasma actuators (MDBD) were initially examined on a flat plate before being applied to the complex geometry of the S-shaped duct. Additionally, the impact of varying plasma applied voltages (6, 6.5, 7, 7.5, 8 kV) and S-duct inlet velocities (24, 35, and 47 m/s) on the performance of the plasma actuators were investigated. Also, the pressure coefficient distribution on the lower surface of the duct was measured under various conditions. The use of MDBD plasma actuators on a flat plate resulted in a significant increase in the maximum induced velocity, approximately 50 % higher than that achieved with a single actuator. This enhancement is attributed to the synergistic effects of the multiple actuators on the induced flow. The application of the MDBD plasma actuator configuration within the S-shaped duct effectively delayed flow separation across all tested inlet velocities (Reynolds numbers of 2.35 × 10<sup>5</sup>, 3.51 × 10<sup>5</sup>, and 4.75 × 10<sup>5</sup>). However, actuator effectiveness decreased with increasing inlet velocity. Higher actuation voltages resulted in a more pronounced delay in separation. Also, at a Reynolds number of 2.35 × 10<sup>5</sup>, the MDBD configuration with 8 kV and 15 Hz achieved a 35.9 % increase in the pressure coefficient compared to the no-plasma condition.</div></div>","PeriodicalId":54842,"journal":{"name":"Journal of Electrostatics","volume":"138 ","pages":"Article 104156"},"PeriodicalIF":2.1,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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