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1. Effects of Particles Diffusion on Membrane Filters Performance

   https://doi.org/10.3390/fluids5030121  

   Liu, Shi Yue ; Chen, Zhengyi ; Sanaei, Pejman ( September 2020 , Fluids)

   null (Ed.)

   Membrane filtration fouling is a very complex process and is determined by many properties such as the membrane internal morphology, membrane pore structure, flow rate and contaminant properties. In a very slow filtration process or during the late stage of filtration, when the flow rate is naturally low and Péclet number is small, particle diffusion is essential and cannot be neglected, while in typical filtration models, especially in moderate and fast filtration process, the main contribution stems from the particle advection. The objectives of this study is to formulate mathematical models that can (i) investigate how filtration process varies under possible effects of particles diffusion; and (ii) describe how membrane morphology evolves and investigate the filtration performance during the filtration process. We also compare the results with the case that diffusion is less important and make a prediction about what kind of membrane filter pore structure should be employed to achieve a particular optimum filtration performance. According to our results, the filtrate and efficiency of particle separation are found to be under the trade-off relationship, and the selection of the membrane properties depends on the requirement of the filtration. 

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2. The effects of buffer condition on the fouling behavior of MVM virus filtration of an Fc‐fusion protein

   https://doi.org/10.1002/bit.27085  

   Namila, FNU ; Zhang, Da ; Traylor, Steven ; Nguyen, Tung ; Singh, Nripen ; Wickramasinghe, Ranil ; Qian, Xianghong ( July 2019 , Biotechnology and Bioengineering)

   A combined pore blockage and cake filtration model was applied to the virus filtration of an Fc‐fusion protein using the three commercially available filters, F‐1, F‐2, and F‐3 in a range of buffer conditions including sodium‐phosphate and tris‐acetate buffers with and without 200 mM NaCl at pH 7.5. The fouling behaviors of the three filters for the feed solutions spiked with minute virus of mice were described well by this combined model for all the solution conditions. This suggests that fouling of the virus filters is dominated by the pore blockage mechanism during the initial stage of the filtration and transformed to the cake filtration mechanism during the later stage of the filtration. Both flux and transmembrane resistance can be described well by this model. The pore blockage rate and the rate of increase of protein layer resistance over blocked pores are found to be affected by membrane properties as well as the solution conditions resulting from the modulation of interactions between virus, protein, and membrane by the solution conditions.

    

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3. A bioinspired, passive microfluidic lobe filtration system

   https://doi.org/10.1039/D1LC00449B  

   Clark, Andrew S. ; San-Miguel, Adriana ( September 2021 , Lab on a Chip)

   Size-based microfluidic filtration systems can be affected by clogging, which prevents their use in high-throughput and continuous applications. To address these concerns, we have developed two microfluidic lobe filters bioinspired by the filtration mechanism of two species of manta ray. These chips enable filtration of particles around 10–30 μm with precise control and high throughput by using two arrays of equally spaced filter lobes. For each filter design, we investigated multiple inlet flow rates and particle sizes to identify successful operational parameters. Filtration efficiency increases with fluid flow rate, suggesting that particle inertial effects play a key role in lobe filter separation. Microparticle filtration efficiencies up to 99% were obtainable with inlet flow rates of 20 mL min −1 . Each filter design successfully increased microparticle concentrations by a factor of two or greater at different inlet flow rates ranging from 6–16 mL min −1 . At higher inlet flow rates, ANSYS Fluent simulations of each device revealed a complex velocity profile that contains three local maxima and two inflection points. Ultimately, we show that distances from the lobe array to the closest local maxima and inflection point of the velocity profile can be used to successfully estimate lobe filtration efficiency at each operational flow rate. 

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4. Seasonal Feeding Behavior of Aquaculture Eastern Oysters (Crassostrea virginica) in the Mid-Atlantic

   https://doi.org/10.1007/s12237-023-01293-9  

   Barr, Janine M. ; Munroe, Daphne ; Rose, Julie M. ; Calvo, Lisa ; Cheng, Kurt M. ; Bayer, Skylar ; Kreeger, Danielle ( November 2023 , Estuaries and Coasts)

   The Eastern Oyster (Crassostrea virginica) is a commercially important aquaculture species and food resource along the Atlantic and Gulf coasts of the USA. In addition to its economic value, oyster aquaculture provides ecological value such as water quality improvement. Oyster filtration is highly variable as filtration behavior is influenced by environmental conditions, oyster size, and oyster energetic demands. However, average rates generated in laboratory experiments are often used to estimate the ecological impact of oyster filtration, and there is a need for field-based, farm-specific estimates of filtration that account for this variation. In this study, field experiments were conducted between September 2020 and September 2021 to estimate seasonal oyster filtration physiology at oyster farms in three different bays in the Mid-Atlantic (Barnegat Bay and Delaware Bay in New Jersey and Rehoboth Bay in Delaware). The physiological activity of oysters at each farm varied such that oysters at Barnegat Bay were the most active and oysters at Rehoboth Bay were the least active. Seasonal physiological trends were observed such that filtration behavior generally increased in warmer months. An increase in physiological activity across all farms was associated with an increase in salinity and temperature, but physiological activity at each farm was associated with a different suite of environmental variables including total particulate matter and the organic content of seston. This study provides a robust dataset which can be incorporated into models estimating ecological filtration rates in the Mid-Atlantic and adds to the growing body of evidence supporting bivalve aquaculture as a nutrient reduction strategy.

    

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5. Structural and functional integrity of decontaminated N95 respirators: Experimental results

   https://doi.org/10.1177/15280837221082322  

   Sharma, Sumit ; Wang, Fang ; Kumar, Shubham ; Nawal, Ruchika_R ; Kumar, Priya ; Yadav, Sudha ; Szenti, Imre ; Kukovecz, Akos ; Schiller, Ulf_D ; Rawal, Amit ( April 2022 , Journal of Industrial Textiles)

   With the recent emergence of highly transmissible variants of the novel coronavirus SARS-CoV-2, the demand for N95 respirators is expected to remain high. The extensive use of N95 respirators by the public is susceptible to demand‐supply gaps and raises concern about their disposal, threatening the environment with a new kind of plastic pollution. Herein, we investigated the filtration performance of the N95 respirator by specifically analyzing the structure in the key filtration layers of meltblown nonwoven after decontamination with one and five cycles of liquid hydrogen peroxide, ultraviolet radiation, moist heat, and aqueous soap solution treatments. With the aid of X-ray microcomputed tomography (microCT) analysis, the local structural heterogeneity of the meltblown nonwoven has been unfolded and subsequently correlated with their filtration performance at a face velocity that matched with speaking conditions (∼3.89 m/s). The filtration efficiency results of the N95 respirator remain unaltered after performing one cycle of treatment modalities (except autoclave).

    

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