Particle Capture Research Articles

The Deep Removal of Mercury in Contaminated Acid by Colloidal Agglomeration Materials M201

The high-temperature roasting/smelting process of copper and zinc concentrates will cause the mercury in the concentrate to evaporate into the flue gas, and most of the mercury in the flue gas will eventually enter the waste acid in its ionic form. A highly efficient mercury removal agent M201 with long carbon chains and loaded active functional groups can adsorb and disperse fine particles for mercury removal in the system. Through bridging, the linear structure is woven into a network to achieve large-scale capture and dispersion of fine particles and colloidal substances. The recommended operating conditions for developing mercury deep purification technology are as follows: M201 reagent concentration of 50 g/L, 6 mL/L added acid solution, room temperature, mixing time of 5 min, air flotation time of 10 min, ventilation rate of 0.1 L/min, H2SO4 concentration of 33.67 g/L, and the residual mercury content of 2 mg/L (the mercury content reaches 0.01 mg/L after two-stage mercury removal treatment). Meanwhile, the residual arsenic content is 21.9 mg/L. This study shows a better separation of arsenic and mercury and achieves one-step mercury removal.

Biodegradable Biconstituent Melt-Blown Nonwovens for Air Filtration: Fabrication and Characterization

Melt-blown polypropylene (PP) is extensively used in air filtration due to its low cost, low weight, and easy processing, but there are increasing environmental concerns due to its non-degradability. On the other side biodegradable polymers such as polylactic acid (PLA) present insufficient strength and limited toughness. Polymer blending is a well-known approach to reach optimum properties from at least two polymers. This study aims to produce biodegradable PP-PLA-based filter materials that possess enhanced elasticity and superior filtration performance. The addition of PLA raises the average fiber diameter (AFD), causing the PP-PLA filters to have AFD ranging from 0.73 to 0.91 μm. However, the incorporation of zinc stearate (ZnSt) decreased the melt viscosity, resulting in thinner fiber formations with AFD ranging from 0.6 to 0.75 μm for PP-PLA-ZnSt. The efficiency of the corona-charged optimized sample (double-layer 75PP-25PLA-ZnSt) showed 97.42% particle capture efficiency and filtration performance of 0.12 mmH2O−1. Despite the presence of hydrophobic surfaces in all filter materials, the addition of ZnSt further improves the resistance to surface wettability. 75PP-25PLA-ZnSt filter material exhibits high stretchability, with a maximum tensile strength of 380 ± 70 kPa. The proposed tricomponent (PP-PLA-ZnSt) approach would be used to reduce the environmental impact of non-degrading polymers.Graphical abstract

Numerical study on Fe3O4 nanoparticle separation from water flow using magnetic field: A 3D simulation

The development of magnetic separation technology using magnetic nanoparticles offers a promising avenue for targeted drug delivery and dealing with the upcoming water crises, environmental pollution and the gradual mineral resource depletion. In this study, a three-dimensional Lagrangian Discrete Phase Model (DPM) is carried out to simulate the performance of Fe3O4 nanoparticles to improve the separation process under the influence of an external magnetic field within a horizontal pipe. The crucial role of the drag force in capture efficiency (CE) prompted its examination, simulating various drag models for groups of particles. The Stokes-Cunningham model, showing a 3.59% average error is a suitable choice compared to experimental results. The research examines the impact of effective parameters, including flow velocity, magnetic field intensity, wire location, particle size and mass flow rate, and pipe diameter on CE and flow pattern. The results show that increasing nanoparticle concentration reshapes the flow pattern due to secondary flows without significantly changing separation efficiency. Moreover, decreasing flow velocity, diminishes drag force and enhances magnetic force impact. Specifically, reducing the velocity to a third increases CE by 37%. Furthermore, capture capacity varies approximately linearly with electric current. Due to the magnetic force’s role as a volumetric force in interphase momentum transfer, the increase in particle size from 200 to 500 nm at 3 × 105 A enhances CE by nearly 50%. However, increasing the pipe diameter diminishes particle capture, attributed to higher Reynolds numbers. According to the results, the impact of increasing magnetic field intensity and particle size on CE improvement is notably more pronounced compared to the effect of flow velocity reduction. A comparative analysis of three injection types reveals that using the group injection type helps to select an appropriate injection location to increase CE and identify the final positions of nanoparticles.

Deep trapped bipolar heterocharges enable electret nanofibrous membranes for high-efficiency PM0.3 filtration

Recently frequent global pandemic outbreak triggers the demand of high-efficiency aerosol filtration materials. Most of traditional electret air filters can hardly achieve high efficiency (>99.99 %) due to limited charge density and inappropriate charge distribution. The influence mechanism of nanofibers bipolar heterocharge configuration on electrostatic capture of airborne particles is still confusing. Herein, a novel strategy to create high-efficiency air filters based on electret nanofibrous membranes with deep trapped heterocharge is reported. Space charges and dipole charges with opposite polarity are formed in electrospun membranes composed of different polymers under in-situ charge injection and electric poling during electrospinning. Nanoscale spatial surface potential mapping on individual nanofiber characterized by Kelvin probe force microscopy demonstrates bipolar heterocharge distribution. Numerical simulation shows that fiber heterocharge distribution endows the electret membrane with greater electrostatic field intensity gradient, resulting in stronger electrostatic force between nanofibers and airborne particles. With bipolar heterocharge configuration and bimodal fiber diameter distribution, the nanofibrous membranes exhibit high-efficiency low-resistance filtration property against 0.3 μm NaCl particles (99.994 %, 97.4 Pa) at 5.3 cm s−1. Furthermore, benefiting from charges with deep trap energy of 1.12 eV, the membranes still maintain 99.972 % filtration efficiency after 40 h exposure in 95 % relatively humidity. The prepared membranes brings new insight in the design of high-efficiency and long-term stability air filtration materials for public health precaution. This study not only reveals influence mechanism of nanofibers heterocharge distribution on electrostatic attraction, but also provides useful guidance for fiber charge configuration design to improve aerosol filtration performance of electret filters.

Coupled photothermal vortices for capture, sorting, and transportation of particles.

Optofluidic techniques have evolved as a prospering strategy for microparticle manipulation via fluid. Unfortunately, there is still a lack of manipulation with simple preparation, easy operation, and multifunctional integration. In this Letter, we present an optofluidic device based on a graphite oxide (GO)-coated dual-fiber structure for multifunctional particle manipulation. By changing the optical power and the relative distance of the fibers, the system can excite thermal fluidic vortices with three inter-coupled states, namely uncoupled, partially coupled and completely coupled states, and therefore can realize capture, sorting, and transportation of the target particles. We conduct a numerical analysis of the whole system, and the results are consistent with the experimental phenomena. This versatile device can be utilized to manipulate target particles in complex microscopic material populations with the advantages of flexible operation, user-friendly control, and low cost.

Study on the application of atomized corona discharge combined with screen electrode in dust collection

This paper presents the design of a novel atomized corona discharge coupled screen electrode dust collector, which integrates electrostatic capture and wet electrostatic dust removal technologies. The upper part of the dust collector features an atomized corona discharge electrode utilizing a threaded-wire hole design with uniform water distribution. This design effectively addresses the issue of electrode fatness that may arise from uneven distribution of the discharge electrode. In contrast, the lower part of the collector is equipped with four side-by-side silk screen electrodes, which serve to expand the dust collection area, facilitate secondary particle capture, and consequently enhance dust removal efficiency. The study delves into a detailed analysis of the impact of various parameters on discharge characteristics and dust removal efficiency, culminating in the identification of optimal parameters.

Enhanced interfacial capture with an elliptical cylinder

Interfacial capture of particles and droplets is important in practical applications. Interfacial capture owing to the surface tension force occurs only when the target (particle or droplet) is close to the collector, leading to low efficiency with collector or collector arrays. An elliptical cylinder instead of a common circular cylinder is a method to enhance capture efficiency. We theoretically investigate this situation by modelling the motion of floating particles around a surface-piercing elliptical cylindrical collector at Reynolds numbers of 1–10. Results indicate that, despite a smaller capture width, elliptical cross-sections, especially with smaller aspect ratios, are more efficient in capturing owing to a much smaller contact line perimeter compared with circular cross-sections. The aligned orientation (the major axis is parallel to the flow) is better than the orthogonal orientation (the major axis is perpendicular to the flow) owing to a larger capture width. A larger collector is beneficial to capillary capture but a very large size is adverse. Smaller but heavier floating particles for smaller capillary numbers can be easily captured at lower Reynolds numbers. The aligned orientation has a greater advantage over the circular cross-section and the orthogonal orientation in the capillary capture. This provides a good method for enhancing the capture efficiency of floating particles in applications.

Evaluation of microplastic particle transmission in a microfiltration process using fluorescence measurements: Effect of pore size and flux

Microplastic (MP) pollution in the aquatic environment is widespread, with a significant fraction of these particles originating from municipal wastewater treatment plant (WWTP) effluents. Whereas membrane filtration processes are touted as an effective MP removal strategy, the rejection of irregularly-shaped plastic particles, similar to those found in WWTPs, is poorly understood. Here, we characterize the filtration of irregularly-shaped MP particles (∼10 μm) through Durapore® microfiltration membranes (0.45 and 5 μm pore sizes). These particles were produced via ball-milling/sieving processes from a fluorescent polyethylene feedstock, enabling particle concentrations to be quantified using a standard fluorometric plate reader. Permeate samples from the 0.45 μm membrane exhibited low fluorescent intensities relative to feed samples, implying minimal MP transmission. Conversely, appreciable MP transmission through the 5 μm membrane was noted, with sizable MPs (∼2–7 μm) found in the permeate. This transmission was exacerbated at higher fluxes which emphasizes how operating conditions can govern MP retention. Post-filtration analyses demonstrated that particle capture occurred largely at the feed-membrane interface, where greater MP intrusion into the membrane was seen at the larger pore size. These results reaffirm the importance of choosing an appropriate membrane/membrane pore size and operating conditions to maximize MP retention in WWTPs.

Design and Analysis of Gas Cyclone with Arc-Shaped Cone Using Bézier Curve for Improved Performance

Abstract The research investigates novel gas cyclone separators with curved conical sections, comparing eight configurations with varying curvature sizes. Gas cyclones are traditionally used as particle separators to remove dust from gas streams, aiming to achieve a dust-free gas flow at the exit pipe while recovering particles to the dust outlet. Computational fluid dynamics (CFD) was employed to model the gas cyclone using the Reynolds stress turbulence model (RSM); the study examines flow fields and pressure losses. It finds that increased curvature correlates with reduced pressure drop. The curved profile is derived from the Bézier curve, characterized by a set of control points determining its shape. This study examines eight cyclone configurations with the intermediate point placed at varying fractions of the main radius: 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, and the main radius itself. The investigation focuses on the impact of different conical segment shapes on cyclone performance, highlighting how convex variants outperform others at higher flow rates while concave variants exhibit higher pressure drop. The pressure drop in the convex variant with an intermediate point position equal to the main radius decreased by 50%. These findings suggest the potential of the convex variant in certain operating conditions over traditional designs with improved particle capture efficiency.

Dynamical characteristics of tightly focused flat-topped double vortex beam for enhanced optical manipulation

The Flat-topped Vortex (FTV) beam has shown remarkable utility in a diverse range of industrial procedures, primarily attributed to its central intensity plateau. Nevertheless, the substantial potential of the FTV beam in particle trapping and manipulation has been largely underappreciated. In this work, we conducted the first study on the focusing properties and dynamic characteristics of the Flat-topped double vortex (FTDV) beam under different polarization for the absorption of Rayleigh particles. Through superimposing linearly two FTV beams with equal but opposite topological charges, the FTDV beam emerged naturally. Moreover, a comprehensive numerical analysis was subsequently performed to decode the interactions between the focusing field of the FTDV beam and Rayleigh particles. The analysis demonstrated that the focusing field of FTDV beam can perform multi-particle capture and effectively manipulate particles by modulating the topological charge |m|, the flatness order n, and the polarization state of the FTDV. Furthermore, a comparison between the focusing field of FTDV beam with that of vector vortex (VV) beam revealed that the FTDV beam was capable to generate spin angular momentum (SAM) density and spin torque at least an order of magnitude higher. These findings highlight the superior capabilities of FTDV beam in optical manipulation, and provide essential theoretical support for its utilization in particle capture and management.

Quantification of full and empty particles of adeno-associated virus vectors via a novel dual fluorescence-linked immunosorbent assay

The adeno-associated virus (AAV) vector is one of the most advanced platforms for gene therapy because of its low immunogenicity and non-pathogenicity. The concentrations of both AAV vector empty particles (EPs), which do not contain DNA and do not show any efficacy, and AAV vector full particles (FPs), which contain DNA, are important quality attributes. In this study, a dual fluorescence-linked immunosorbent assay (dFLISA), which uses two fluorescent dyes to quantify capsid and genome titers in a single analysis, was established. In dFLISA, capture of AAV particles, detection of capsid proteins, and release and detection of the viral genome are performed in the same well. We demonstrated that the capsid and genomic titers determined by dFLISA were comparable to those of analytical ultracentrifugation. The FP ratios determined by dFLISA were in good agreement with the expected values. In addition, we showed that dFLISA can quantify the genomic and capsid titers of crude samples. dFLISA can be easily modified for measuring other AAV vector serotypes and AAV vectors with different genome lengths. These features make dFLISA a valuable tool for the future development of AAV-based gene therapies.

Random walk characteristics of particles in slurry pipeline transportation

During the pumping of wet shotcrete in a pipe, the aggregate migrates under various forces. In order to investigate the random walking characteristics of particles in slurry pipeline transportation, particle tracking platform for half-open tubes was constructed. Cement-like slurry colloids were prepared. The particle capture function of high-speed camera was utilized to track the particle movement. Random walk theory was used to analyze the transport trajectories of aggregates with different particle sizes. The transport properties of the particles were quantitatively analyzed. The experimental results showed that cement-like slurry colloids were obtained by using a mixture of powder of xanthan gum, carbomer, polyacrylamide and water mixed in a certain proportion. The trajectory of particle transportation in the slurry pipe had a large correlation with the particle size. In a straight pipe, the smoothest particle trajectories were found in the range of 4.17–6.25 % of the pipe diameter. The spectral dimension was positively correlated with tortuosity and more highly correlated with particle size in pipeline transport. The number of spectral dimensions and tortuosity were negatively correlated with axial walking steps of the particles. This paper provided a new way of thinking to study the particle transportation law in concrete pipeline.

Non-uniform magnetic particle capture based on single-fiber optical tweezers

In this study, single-fiber optical tweezers are used to capture polystyrene magnetic particles with non-uniform surfaces. By preparing the tip of the optical fiber probe in the shape of a protruding cone, the laser beam is highly converged at the tip of the fiber to form a strong focused light field, and the laser beam can pass through the gap between the inorganic magnetic particles on the surface of the magnetic particles and enter into the internal polystyrene to generate a gradient force and realize the stable capture of the magnetic particles. This method provides a feasible and effective solution for the capture of non-uniform polystyrene magnetic particles using optical fiber and opens up new possibilities for research in related fields.

Design and application of environmentally friendly composite magnetic particles for microplastic extraction from water media

The widespread presence of microplastic particles in aquatic environments requires methods of their extraction from water for counting and analysis and for water purification technologies. In this study, new magnetic composite nanoparticles (FNP) were designed, characterized and explored to be used as magnetic seeds for extracting polyethylene terephthalate microparticles (MPET, 5–30 μm) from water by magnetic sedimentation. The engineered seeds have a complex morphology, with magnetic cores of Fe3O4 dispersed in an environmentally compatible polymer matrix of silicon dioxide, chitosan or gelatine. Mechanisms of the heteroaggregation of FNP and MPET are considered and the main influencing factors (particles concentrations, major ions, duration of the preliminary exposure and of the sedimentation) are studied. The heteroaggregates are removed from water using a gradient magnetic field (Bzmax = 0.44 T) generated by a system of permanent magnets. The mass concentration of magnetic nanoseeds for more than 98 % capture of PET particles in pure and in salted water after 0.5 hour of magnetic sedimentation was detected to be 0.002 g/L. It is two orders of magnitude lower than that reported for uncovered magnetite-based particles. Using magnetic composite seeds with ecofriendly coatings allows to perform a high efficient magnetic separation of microplastic particles from water both for analytical purpose and for potential water cleaning technologies, while strongly reducing the synthetic flocculant sludge volume.

Fine particle capture performance assessment in an electrostatic-fabric integrated precipitator

Electrostatic precipitators, which are more commonly referred to as precipitators, play a crucial role in the process of reducing the quantity of airborne contaminants that are present in both atmospheric and flue gas settings. This is because precipitators are able to lower the concentration of contaminants in the air. The fine particles, ash, and oil that make up these pollutants are included. With a special emphasis on a Cottrell-type electro-filter that makes use of the wire-cylinder arrangement, the goals of this study are to evaluate the practicability of various filtration systems for the purpose of air decontamination. Specifically, the study will focus on the Cottrell-type electro-filter. By conducting a thorough examination of the peculiarities of the electrical and physical parameters that regulate the mechanisms of particle aggregation, our major purpose is to achieve a comprehensive understanding of these parameters. Through the use of experimental design strategies, we will make an effort to construct and perfect the filtration process in the subsequent stage. In addition to that, the purpose of this inquiry is to explore the impact that high voltage levels and the diameter of the conductor wire that is incorporated into the prototype have. Especially notable is the fact that our prototype exhibits an incredible filtration efficiency, with rates reaching up to 98%. This performance is really remarkable. Its exceptional performance reveals that it has the potential to be suitable for a wide variety of contexts, including residential, commercial, healthcare, industrial, and workshop applications. This suggests that it has the potential to be suitable for a wide range of applications.

EchoGrid: High-Throughput Acoustic Trapping for Enrichment of Environmental Microplastics.

The health hazards of micro- and nanoplastic contaminants in drinking water has recently emerged as an area of concern to policy makers and industry. Plastic contaminants range in size from micro- (5 mm to 1 μm) to nanoplastics (<1 μm). Microfluidics provides many tools for particle manipulation at the microscale, particularly in diagnostics and biomedicine, but has in general a limited capacity to process large volumes. Drinking water and environmental samples with low-level contamination of microplastics require processing of deciliter to liter sample volumes to achieve statistically relevant particle counts. Here, we introduce the EchoGrid, an acoustofluidics device for high throughput continuous flow particle enrichment into a robust array of particle clusters. The EchoGrid takes advantage of highly efficient particle capture through the integration of a micropatterned transducer for surface displacement-based acoustic trapping in a glass and polymer microchannel. Silica seed particles were used as anchor particles to improve capture performance at low particle concentrations and high flow rates. The device was able to maintain the silica grids at a flow rate of 50 mL/min. In terms of enrichment, the device is able to double the final pellet's microplastic concentration every 78 s for 23 μm particles and every 51 s for 10 μm particles at a flow rate of 5 mL/min. In conclusion, we demonstrate the usefulness of the EchoGrid by capturing microplastics in challenging conditions, such as large sample volumes with low microparticle concentrations, without sacrificing the potential of integration with downstream analysis for environmental monitoring.

Structural adaptations of the beak and oropharyngeal cavity roof in migratory Anas crecca: Distinctive scanning electron microscopic pattern of its filter feeding apparatus

There is insufficient data about the migratory duck Anas crecca, especially the beak and oropharyngeal cavity roof. This study aimed to characterize the beak and palatine adaptations and relate the morphological features with the species-specific feeding behavior of A. crecca collected near Lake Nasser (Egypt). Our study was carried out with the help of gross, scanning electron microscopy (SEM), and morphometric analysis. The lower median papillary teeth-like region corresponded to the lower papillary region in terms of food particle capture. The serrated gnathotheca surface exhibited transverse, wedge-like, cap-like, and serrated border-like processes. The lower mandibular space had four spaces: the rostral smooth, the middle folded, the long sublingual, and the caudal sublaryngeal space. The palate showed two major regions, the rostral long beak (beak nail, middle part, and the caudal papillary part) and the connecting region. The choana consists of the rostral narrow part, which has rostral non-papillated and caudal papillated parts, and the caudal papillated wide part, which has three papillary rows. The infundibular plate had numerous small papillae and sphenopterygoid salivary gland openings. Functionally, the beak plays an important role in the sieving filter feeding mechanism, and the palate is involved in the fixation of the captured food particles inside the oral cavity. Consequently, beak and palate structures exhibit anatomical adaptations for efficiently filtering feeding mechanisms.

Plugging of pipes by cohesive particles. Computed tomography investigation and theoretical analysis

Flow regimes leading to clogging of pipes exist for most multiphase flows with cohesive particles. Although plugging is critical in many industrial and medical applications, there are few records describing the details of the process. To address the problem, we conduct a computed tomography (CT) study of plugging in a cohesive ice slurry. We run experiments for ice concentration of 15%, Re∼3500, particle size 0.2-0.4 mm, and their surface energy ∼150 mJ/m2. The CT scans, combined with experimental logs of the main flow parameters, revealed the formation of deposits around the orifice inserted into the pipe, with a complete blockage formed downflow the orifice. The deposition efficiency of ice was relatively low ∼ 10−3. Reproducing the experimental deposition efficiency with the Lagrangian CFD model, we extracted the probability of particle capture at the orifice, which was about 0.5%. The simulation results illustrated how inter-particle interactions hindered the plugging.

Double-Ring perfect vectorial vortex beams distribution regulation

Perfect vector beams with radius independent of topological charges have garnered significant interest owing to their unique capabilities in optical manipulation, microscopy imaging, and laser micro-machining. However, their polarization state is limited to four modes, restricting their information capacity and re-usability. To address this, we introduce double-ring perfect vectorial vortex beams that leverage the axicon phase to theoretically generate double-ring structures through a Fourier transform. By applying a transformation matrix and introducing a cross phase, we can manipulate the beam distribution. This approach is expected to enhance for development of particle capture and optical communications.

Impact of pH, ionic strength, and operating conditions on capture mechanisms in nanoparticle filtration

Filtration of biopharmaceutical streams can be complex due to the variety of components in the stream and their interactions among themselves and with the filter pore surfaces. This work used a variety of measurements to study the filtration of model silica nanoparticles through asymmetric hydrophilized polyethersulfone (mPES) membrane in solutions covering a range of pH and ionic strengths. Measurements included particle size, particle concentration, zeta potential, particle-particle and particle-membrane surface intermolecular forces. These measurements were used to rationalize observed particle capture behavior under various filtration conditions. We found that increasing ionic strength and decreasing pH resulted in higher particle aggregation and higher particle retention due to adsorption of model silica nanoparticles to the membrane and sieving of aggregates within the membrane. In addition, captured particles can be eluted from the membrane in some cases, depending on the operating conditions, extent of particle loading, buffer flush pressure, and buffer pH and conductivity conditions. These findings provide insight into methods to improve filtration performance and particle capture or release, including product recovery, in filtration processes.