Journal: Separation and Purification Technology

Abbreviation

Publisher

Elsevier

Journal Volumes

ISSN

1383-5866

Description

Filters

2010 - 2019112020 - 202521
Reset filters

Search Results

Publications 1 - 10 of 32
  • Combination of genetic algorithm and CFD modelling to develop a new model for reliable prediction of normal shock wave in supersonic flows contributing to carbon capture
    Item type: Journal Article
    Shooshtari, Seyed Heydar Rajaee; Walther, Jens Honoré; Wen, Chuang (2023)
    Separation and Purification Technology
    Carbon dioxide separation and capture using green and efficient methods is an important issue in studies related to climate change. The supersonic separator is one of the efficient and reliable methods that can be used to separate impurities, including carbon dioxide, from gas streams. Reliable estimation of normal shock wave position plays a vital role in the proper design and simulation of supersonic separators. Many studies have used a one-dimensional theoretical (ideal) model of a normal shock wave for the estimation of the shock position and pressure recovery, but the accuracy of the ideal model of normal shock may be insufficient in some situations, as reported in the literature. A novel approach is presented in this paper to provide new equations for normal shock waves by the combination of computational fluid dynamics (CFD) and genetic algorithm. The comparison of the proposed model with several experimental data and the ideal model of a normal shock wave indicate that the present model provides more accurate predictions than the traditional model of a normal shock wave. The present model showed an average absolute relative deviation (AARD) of 1.80%, which is about six times less than AARD of the ideal model, indicating the robustness of the proposed model. Consequently, the present model can be employed as an accurate and efficient tool for the prediction of shock position and design of converging–diverging nozzles.
  • Aerodynamic property and filtration evaluation of airborne graphene nanoplatelets with plate-like shape and folded structure
    Item type: Journal Article
    Gao, Hanchao; He, Weidong; Yu, Ranxue; et al. (2020)
    Separation and Purification Technology
    With the wide applications of graphene nanoplatelets (GNPs) in the industries, more concerns are raised about the effectiveness of filtration technology to control GNPs release during manufacturing and handling processes. Accurate prediction of the capture efficiency of airborne GNPs is significant to avoid occupational exposure. Herein, the aerodynamic property and filtration mechanisms of airborne GNPs with plate-like shape and folded structure were studied. Different equivalent diameters of GNPs (aerodynamic diameter da, mobility diameter dm) were derived and used to describe diverse mechanisms in the filtration model. The capture efficiency of plate-like GNPs and sphere-like NaCl particles was measured with Nuclepore membranes and nanofibrous membranes to assess the particle shape effect during filtration. The plate-like GNPs showed higher capture efficiency due to the larger interception length. SEM measurement showed that not only planar GNPs, GNPs with folded structure also occurred due to the large lateral size to thickness ratio and strong mechanical stimulation in the atomization process. For GNPs with aerodynamic diameter of 0.5 – 0.9 μm, the capture efficiency for folded GNPs decreased by 20 – 30% according to the analytical calculation. In addition, the effects of membrane structural parameters (Nuclepore membrane pore radius, fiber diameter, solidity) on the quality factor (Qf) were systematically analyzed to evaluate the overall filtration performance. This study not only elucidates the effect of plate-like shape and folded structure on the aerodynamics of airborne GNPs, but also contributes to better design of Nuclepore and nanofibrous membranes to improve the filtration performance of plate-like particles.
  • Modeling, evaluation, and optimization of a self-bearing spinfilter for bioseparations
    Item type: Journal Article
    Beglinger, Lars; Steinert, Daniel; Nussbaumer, Thomas; et al. (2025)
    Separation and Purification Technology
    Rotating filters promise many advantages for long-term separation processes of complex media such as cell cultures, but have never been commercialized on a large scale due to practical challenges and limited scalability. A bearingless spinfilter circumvents many of the drawbacks, yet additional considerations must be taken into account. Thus, an existing particle-force based model for cross-flow filtration, dependent on the membrane shear rate and the transmembrane pressure, is adapted to the spinfilter and predicts the behavior of retained particles at the membrane. Computational fluid dynamics simulations allow to calculate the shear rate at the membrane for the model. Additionally, with the simulated distribution of the shear rate and the energy dissipation rate within the spinfilter, a prediction of the hydrodynamic stress on cell cultures can be made. The model is verified with a spinfilter prototype on a yeast cell culture and is in good agreement with experimental results. Additional separation experiments with bovine blood serve to indicate the extent of cell damage induced by hydrodynamic stress within the spinfilter. The results demonstrate that operating the spinfilter at the optimum operation point leads to a faster separation process at a lower level of cell damage per volume of filtrate in comparison to a passive tangential flow filtration in hollow fibers.
  • Scaling up magnetic filtration and extraction to the ton per hour scale using carbon coated metal nanoparticles
    Item type: Journal Article
    Rossier, Michael; Schreier, Marcel; Krebs, Urs; et al. (2012)
    Separation and Purification Technology
  • Application of microfibrillated fibers in robust and reusable air filters with long service time in the ambient with high oily aerosols concentration
    Item type: Journal Article
    Hu, Jian; Yao, Yunzhen; Liu, Sihan; et al. (2022)
    Separation and Purification Technology
    There are two challenges in the application of dual-layer structured nanofibers composite filters (1) they tend to deteriorate easily during the air cleaning process for reuse; (2) their service time under the condition with high oily aerosol concentration is only half of that under the condition with pure solid particles. In this study, fibrillated fibers are used to fabricate robust dual-layer structured air filters. The influence of the content of fibrillated fibers in the filters on their performance is studied. Their performance is compared with a kind of commercial electrospinning nanofibers composite filters that had similar initial filtration efficiency. They have longer service time than the commercial filters contributing to their longer duration and lower residual pressure drop of the cleaning cycles. They are more robust than the commercial filters. Their dust holding capacity against the diisooctyl sebacate (DEHS)-A2 dust mixture with different DEHS content is 1.6 to 5.1 times that of the commercial filters. This study indicates that fibrillated fibers can be utilized to develop robust and reusable filters with a long service time, especially in harsh conditions with abundant oily aerosols.
  • Insights into ultrasound-enhanced methyl orange decolorization using transition metal dichalcogenides nanoflowers
    Item type: Journal Article
    Veciana, Andrea; Wu, Jiang; Qin, Ni; et al. (2025)
    Separation and Purification Technology
    Ultrasound-assisted dye removal using transition metal dichalcogenide (TMD) nanostructures is frequently attributed to piezocatalysis; however, the actual mechanisms involved remain poorly understood. In this study, we investigate the role of physical adsorption in the rapid decolorization of methyl orange (MO) using few-layered MoS₂ and MoSe₂ nanoflowers (NFs) under ultrasonic treatment. Remarkably, complete decolorization was observed within 10 s. Through systematic desorption experiments in ethanol, combined with UV-Vis spectroscopy and Raman analysis, we demonstrate that this rapid removal is dominated by strong electrostatic adsorption rather than catalytic degradation. Quantitative analysis revealed recovery rates of 98.8 % for MoS₂ and 88.8 % for MoSe₂, confirming the molecular integrity of MO post-desorption. Density functional theory (DFT) calculations highlight the contribution of interfacial charge transfer to the adsorption process. Our findings underscore that sono-adsorption, rather than piezocatalysis alone, plays a predominant role in dye removal using TMDs and call for a more rigorous mechanistic distinction in future ultrasound-driven piezocatalytic studies.
  • A comparison study of the filtration behavior of air filtering materials of masks against inert and biological particles
    Item type: Journal Article
    He, Weidong; Yue, Yang; Guo, Yinghe; et al. (2023)
    Separation and Purification Technology
    Inert particles are widely used as surrogates for biological particles in filtration tests. However, there is always a concern that the different physical properties between inert particles and biological particles may affect the filtration efficiencies of filter media. In the present study, the inert particles, e.g. NaCl and polystyrene latex (PSL), and biological particles, e.g. E.coli, B.sublitis, bovine serum albumin (BSA), and endotoxin, were used to evaluate the filtration efficiencies of the filtering materials of a surgical mask and a N95-rated respirator. The results showed that the difference in the filtration efficiencies of the N95-rated respirator for the tested inert particles and biological particles was smaller than 0.02%. The filtration efficiency of the surgical mask for PSL particles was lower than that for E.coli and B.subtilis particles with the same aerodynamic diameter because of the larger interception lengths of E.coli and B.subtilis particles. The average filtration efficiencies of the surgical mask for the tested NaCl particles and biological particles in the size range of 20–600 nm were similar. For the monodisperse particles, the filtration efficiency of the surgical mask for NaCl, BSA and endotoxin particles in the size range of 50–250 nm decreased in the above order due to the different shapes, dielectric properties, and multiply-charged fractions of the particles. The surgical mask presented the highest filtration efficiency for BSA particles and the lowest filtration efficiency for NaCl particles when the particle size was larger than 300 nm, which could be related to the difference in the electrostatic deposition and bounce probabilities. The present work revealed that the influence of several particle characteristics such as shape, dielectric property, and charge state on filtration efficiency should be considered when using common inert particles to replace biological particles to measure efficiencies of air filters.
  • Bacterial growth in batch-operated membrane filtration systems for drinking water treatment
    Item type: Journal Article
    Mimoso, Joao; Pronk, Wouter; Morgenroth, Eberhard; et al. (2015)
    Separation and Purification Technology
  • Filterability prediction of needle-like crystals based on particle size and shape distribution data
    Item type: Journal Article
    Perini, Giulio; Salvatori, Fabio; Ochsenbein, David R.; et al. (2019)
    Separation and Purification Technology
    The isolation and further treatment of particles generated in a crystallization process is dependent on their size and shape. The work presented here analyzes the filtration performance of needle-like particles, which often exhibit long filtration times or high retention of mother liquor. The size and shape of populations of l-Glutamic Acid and d-Mannitol particles are measured using an automated image analysis approach (as well as a standard light scattering method), and their associated cake resistance is determined in pressure filtration experiments. Using a partial least squares regression analysis we develop a model of the process and show that relative cake resistances can be predicted if the particle size distributions are accurately known. Furthermore, we show that the statistical model calibrated on a single compound (either of those used for this study), can be exploited to predict the relative cake resistances of another compound.
  • Charge characteristics of co-electrospun nanofiber membranes and their application in high-humidity environment
    Item type: Journal Article
    Guo, Yinghe; He, Weidong; Liu, Jingxian; et al. (2025)
    Separation and Purification Technology
    Enhancing the charge density and charge stability is an important approach to improve the filtration performance of electrospun nanofiber air filters. In the present study, the polymers with different electron transport capabilities were co-electrospun in pairs to prepare charge-enhanced nanofiber membranes. The results showed that the average surface potential of the interfacial regions of polyamide 6 (PA6) and polyvinyl chloride (PVC) nanofibers was 165 mV, which was substantially higher than the non-intersection area of nanofibers. The charges induced by the contact-induced electrification between nanofibers accumulated in the intersection area of the hybrid nanofibers, which contributed to the high surface potential of the nanofiber membranes. Moreover, the co-electrospinning of polymers allowed the positively charged PA 6 nanofibers and negatively charged PVC nanofibers to coexist in the nanofiber membranes. Benefiting from these charge characteristics, the co-electrospun PA 6/PVC nanofiber membranes exhibited an average filtration efficiency of 99.73 % for 50–500 nm particles at the face velocity of 5.3 cm/s, and the pressure drop was 130 Pa. A hydrophilic fiber layer was employed to mitigate the influence of humidity on the charge decay and pressure drop growth of the nanofiber membrane. The growth rate of pressure drop of the protected nanofiber membrane was as low as 0.95 Pa/min under the challenge of water droplets. In contrast, the growth rate of pressure drop for common membrane based filters was in the range of 5–120 Pa/min. Additionally, the color of the hydrophilic layer changed corresponding to the water content in the air filters, which could serve as an indicator for the filter service life visible to naked eyes. This study provides a new approach for charging nanofiber membranes and improving their filtration performance stability in practical applications.
Publications 1 - 10 of 32