Polyester Filter Research Articles

Enhancement of the degradation capacity of IsPETase by acidic amino acids insertion and carbohydrate-binding module fusion.

The biocatalytic degradation of poly(ethylene terephthalate) (PET) through enzymatic methods has garnered considerable attention due to its environmentally friendly and non-polluting nature, as well as its high specificity. While previous efforts in enhancing IsPETase performance have focused on amino acid substitutions in protein engineering, we introduced an amino acid insertion strategy in this work. By inserting a negatively charged acidic amino acid, Glu, at the right-angle bend of IsPETase, the binding capability between the enzyme's active pocket and PET was improved. The resulted mutant IsPETase9394insE exhibited enhanced hydrolytic activity towards PET at various temperatures ranging from 30 to 45 ℃ compared with the wild-type IsPETase. Notably, a 10.04-fold increase was observed at 45 ℃. To further enhance PET hydrolysis, different carbohydrate-binding modules (CBMs) were incorporated at the C-terminus of IsPETase9394insE. Among these, the fusion of CBM from Verrucosispora sioxanthis exhibited the highest enhancement, resulting in a 1.82-fold increase in PET hydrolytic activity at 37 ℃ compared with the IsPETase9394insE. Finally, the engineered variant was successfully employed for the degradation of polyester filter cloth, demonstrating its promising hydrolytic capacity. In conclusion, this research presents an alternative enzyme engineering strategy for modifying PETases and enriches the pool of potential candidates for industrial PET degradation.

Electric-field activating on-surface tailored (OST) coarse polyester fibers for efficient airborne particle removal: Interfacial morphologies and electrical response

Fibrous filtration is the most-used method for indoor particulate matter (PM) removal. The filtration performances are governed by filters’ intrinsic geometries, displaying the tradeoff among efficiency, resistance, and lifespan. In this contribution, we provided a chemically-synthesized strategy to improve the performance of coarse filters while preserving their ultralow initial resistances. After elucidating PM-fiber interactions, the fibrous interfacial nano-morphologies were tailored by different dielectric coatings based on commercially-available substrates. Activated by fiber polarizing, the tuned morphologies with ∼100 nm surface roughness and enhanced electrostatic potential are considered the drivers of boosted filtration efficiency. In practice, a 10-mm-thick polydopamine (PDA)-MnOx coated polyester filter possessed an improved efficiency of 97.7 % for 300–500 nm particles, and the ultralow resistance of 11.2 Pa at 0.5 m/s filtration velocity. The strong surface adhesion facilitated long-term efficiency of 95.6 % in a continuous 25-day period without any decay. The nanoscale coatings, which were just one-thousandth in thickness of the fiber gaps, enabled more than 50-fold improvement of the filters’ quality factor. We further established dimensionless factors to evaluate the cost-performance effect. We expect the strategy and techniques can pave the way to better understand electrostatic air filtration, being competitive candidates in the air filtration community.

Integrated surface microstructure and enhanced dielectric constant for constructing simple, low-cost, and high-performance flexible capacitive pressure sensor

Designing microstructure surface or enhancing the dielectric constant of functional layer is a common useful strategy to improve the pressure sensing performances of flexible capacitive pressure sensors, but it usually involves complex preparation processes (such as artificial microstructure and preparation of composite materials). Considering the limitations of a single strategy in improving the pressure sensing performance of capacitive pressure sensor, herein, we propose a simple strategy that integrates surface microstructure and enhanced dielectric constant of functional layer for constructing a high-performance flexible capacitive pressure sensor. Specifically, the polyester fiber conductive tape and filter paper with intrinsic rough surfaces are selected as microstructure electrodes and dielectric layer, respectively. Meanwhile, by introducing the daily carbon ink into filter paper, the moderate conductivity of the carbon ink is utilized to enhance the dielectric constant of the filter paper dielectric layer. The results show that the proposed the pressure sensor has wide pressure detection range of 0.1−100 kPa, high sensitivity (1.47 kPa−1, 0.1−10 kPa) and good durability (4000 cycles at 20 kPa). Taking the pressure range of 10−100 kPa as an example, the sensitivity of carbon ink paper-based sensor is 60 times higher than that of sensor without carbon ink. The enhanced working mechanism of the sensor is clarified by combining testing and characterization. In addition, the proposed pressure sensor has potential applications in wrist pulse, respiratory rate, walking record, morse code transmission，and stoma bag detection. This work provides a useful reference for constructing simple, low-cost and high-performance flexible capacitive pressure sensor.

#2490 Analyzing the morphology of mesothelial cells when exposed to peritoneal dialysis solutions

Abstract Background and Aims Glucose remains the predominant osmotic agent in peritoneal dialysis (PD), yet its prolonged use is associated with an inevitable decline in peritoneal filtration capacity. Persistent contact with glucose during dialysis can induce significant morphological and functional changes in the peritoneum. In this study, we explore the morphological alterations in mesothelial cells exposed to both conventional glucose-based PD solutions and an innovative biocompatible PD solution (XyloCore) containing L-carnitine and Xylitol. Method Met5A mesothelial cells were seeded and cultured on a polyester filter (with a pore size of 0.4 micrometers, Transwell, 12 well type, Millipore) utilizing a full medium. The impact of PD solutions, differentiating between glucose-based and XyloCore, was assessed on cells cultivated on transwells. These cells were exposed to PD solutions on the apical side and to culture medium on the basal side. The cells were then employed for proteomic and metabolomic assessments and were also fixed and scrutinized through scanning electron microscopy (SEM). Results Through unsupervised hierarchical clustering analysis, discernable proteomic distinctions emerged between wild-type (WT) cells (control) and cells exposed to either glucose-based PD solution or XyloCore. In SEM analysis, control cells exhibited a distinct flat epithelial appearance. Contrastingly, subjecting WT cells to treatment with a glucose-based PD solution induced significant alterations in cellular morphology. Notably, cells displayed elongated shapes, loosening of cell-cell contacts, and a consistent denuding of the culture surface. In contrast, XyloCore maintained a better cellular morphology and mitigated cell detachment. Conclusion Preserving the integrity of the mesothelial barrier is crucial for maintaining peritoneal ultrafiltration capacity. The findings suggest that glucose-based PD solutions trigger early morphological changes in cell shape and cell-cell contacts, likely stemming from alterations in cytoskeleton or adhesion molecules. The exploration of new osmotic agents in clinical practice holds paramount significance for the future of peritoneal dialysis.

One-step fabrication of Nafion-TiO2 composite immobilized on polyester filters for efficient photocatalytic applications

One-step fabrication of Nafion-TiO2 composite immobilized on polyester filters for efficient photocatalytic applications

Impact of progressive pulse cleaning pressure on polyester filter media performance using pulse jet filtration test rig

Impact of progressive pulse cleaning pressure on polyester filter media performance using pulse jet filtration test rig

Performance of surface finished polyester filter media exposed to different dust types with the variation of dust concentration

Emissions of dust from industrial plants pose the greatest threat to environment and human health. Pulse-jet cleaning is the most efficient system to control industrial emissions. The present study consisted of four surface-treated filter media exposed to two dust types at three dust concentrations. The filtration performance in terms of filter efficiency is determined by the PM emissions, number concentration and gravimetric mass emissions of particles. Additionally, the filter performance is assessed by residual pressure drop and depth of dust penetration. The dust emissions, residual pressure drop, and depth of dust penetration are found to be lowest for needle-punched membrane (NPM) media. Apart from NPM, the needle-punched spun-laced water-repellent finished media showed better results than the other two surface filters used conventionally. For residual pressure drop, dust type contributes more at lower dust concentration levels. However, media (surface finish) surpasses the effect of dust type at higher dust concentration levels.

Effect of varying cycle time interval and aerosol pre-charge on filtration performance of polyester media

Present study embodies filtration characterization of two nonwoven needle-felt polyester filter materials, viz. PTFE coated and without coated media. The materials have been assessed using flyash aerosol under varying time intervals (6, 9 and 12 min) at different inlet dust densities (50, 90 and 150 g/m3). The flyash particles are charged prior to their deposition over the filter media using a three phase parallel plate box pre-charger at two different levels of pre-charge, viz. 4 kV and 8 kV along with 0 kV. Results reveal that the filtration performance for PTFE coated material is better under all conditions. However, an enhanced filtration performance in terms of particle emission and pressure drop is noted at increased pre-charge level and higher cyclic interval. It may also be noted that the level of improvement in filtration behavior for both the materials has been better at initial level of pre-charge from 0 kV to 4 kV. However, the cumulative behavior of all the factors is also found significant.

A two-stage cascaded ionizer for boosting PM charging in electrostatic filtration: Principles, design, and long-term performance

In fibrous filtration for airborne particulate matter (PM), the triple wins among efficiency, resistance, and lifetime are hard to achieve owing to the filters’ intrinsic geometry. Although charging the PM has been extensively exploited, it is still far from satisfactory for practice, with drawbacks including electrode fouling, ozone, and durability. Herein, based on low-efficiency coarse filters with ultralow pressure drop and potential large dust holding capacity, we bridge this divide by introducing two-stage cascaded ionizers to boost their performance. Enabled by the separated structure for successive ion generation and transport, theoretical design and experimental results demonstrated that the ionizers could efficiently charge the PM and promote filtration efficiencies. The lab-scale prototype composed of the prepared ionizer arrays and polyester (PET) filters stably performed in 25 days, with average daily efficiency of 95.4% for 0.3–0.5 μm particles, 77.0 g/m2 PM10 accumulating amounts with 4.9 Pa pressure drop, and 56.2 W/m2 power consumption at 1.4 m/s filtration velocity. As the “efficiency boosters” for filters, the ionizers are meanwhile free of PM contamination and possess ultralow ozone generation. We anticipate that our approach will be an efficient, durable, and energy-effective solution in the air filtration community in ventilation systems for clean and sustainable built environments.

Modifying the Fiber Structure and Filtration Performance of Polyester Materials Based on Two Different Preparation Methods.

How to build a satisfactory indoor environment has become increasingly important. In this paper, the synthesis and improvement of the most widely used polyester materials in China were carried out based on two different preparation methods, and the structures and filtration performances were tested and analyzed. The results showed that a carbon black coating was wrapped on the surfaces of the new synthetic polyester filter fibers. Compared with the original materials, the filtration efficiencies of PM10, PM2.5, and PM1 were increased by 0.88-6.26, 1.68-8.78, and 0.42-4.84%, respectively. The best filtration velocity was 1.1 m/s, and the new synthetic polyester materials with direct impregnation demonstrated superior filtration performance. The filtration efficiency of the new synthetic polyester materials was improved on the particulates with sizes of 1.0-5.0 μm. The filtration performance of G4 was better than that of G3. The filtration efficiencies of PM10, PM2.5, and PM1 were improved by 4.89, 4.20, and 11.69%, respectively. The quality factor value can be used to assess the comprehensive filtration performance of air filters in practical applications. It could provide reference values for the selection of synthetic methods of new filter materials.

Sunlight and red to far-red ratio impact germination of tropical montane cloud forest species

Context Australia’s tropical montane cloud forests (TMCF) exhibit exceptional species richness and endemism. Determinants of regeneration via seed of these species are next to unknown, limiting our ability to quantify and project their vulnerability to climate change. The ratio of red to far-red light (R:FR) has been shown to influence seed germination of many tropical species. Aims We investigated germination of six previously unstudied TMCF species in relation to the presence or absence of light (light/dark) and light quality (R:FR). We hypothesised that increased R:FR would lead to increased germination and that small-seeded species would be more likely to have a light requirement and be less sensitive to R:FR compared to larger-seeded species. Methods Sunlight and polyester filters were used to create a gradient of R:FR ranging from 0.1 to 1.14. Seeds were also sown in constant darkness. Key results Across species we saw varying germination responses. Three of the four smallest-seeded species exhibited an absolute light requirement for germination and did not discriminate between different R:FR. Germination of the small-seeded TMCF endemic Dracophyllum increased exponentially with increasing R:FR. Germination of the largest-seeded species was inhibited by both low and high R:FR, and germination was higher in constant darkness than diurnal light/dark. All six species were able to germinate at remarkably low R:FR values. Conclusions Light affects seed germination of Australia’s TMCF plant species in a variety of ways. Implications The findings of this study provide insights into plant recruitment in situ, and the acclimation potential of these species under reduced R:FR predicted for the future.

Calcium stearate nanoparticles as building blocks for mechanically durable superhydrophobic coatings

Mechanical durability and cost-efficiency are two main concerns in moving superhydrophobic coatings toward real-life applications. However, the development of inexpensive, simple, and large-scale strategies for preparing superhydrophobic coatings that are simultaneously mechanically durable and low-cost is still challenging. Herein, we proposed a one-step dip-coating approach for in situ growing calcium stearate nanoparticles on the desired substrates simply by using commercially available calcium stearate and a suitable selection of solvents. The resulting superhydrophobic calcium stearate nanoparticle coatings show excellent mechanical durability under 100 cycles of sandpaper abrasion and 300 cycles of tape peeling, good stability towards UV light irradiation, thermal treatment and organic solvents. Furthermore, the as-prepared calcium stearate nanoparticle-coated polyester filter cloth was successfully demonstrated for oil/water separation. It is believed that such simple, rapid and cost-efficient approach provide a valid strategy and promising applications for large-scale fabrication of mechanically durable superhydrophobic coatings.

Discovering of the photocatalytic performance of BiFeO3/BNQDs immobilized polyester filters for efficient continuous-flow elimination of recalcitrant antibiotic via PMS activated process

Finding effective and practical elimination systems for harmful contaminants is a challenging issue and thereby, construction of scalable materials has gained attention in advanced oxidation processes. Herein, BiFeO3 (BFO) perovskites were first incorporated with boron nitride quantum dots (BNQDs) via impregnation technique and then the BFO/BNQDs catalysts were immobilized on commercial polyester (PE) filters via dip-coating method (BFO/BNQDs@PE). It was aimed to enhance the photocatalytic performance of perovskite catalyst via incorporation of BNQDs and restrict the disadvantages of powder form of catalysts via immobilization on filter. SEM images revealed that the BFO/BNQDs particles were uniformly coated on the polyester fiber. The XRD pattern demonstrated that the immobilization process did not alter the crystal structure of perovskite. The catalytic performance of the system was investigated via degradation of tetracycline-hydrochloride (TC-HCl) in batch as well as continuous flow conditions and the dual-effect catalytic system was generated by introducing peroxymonosulfate (PMS) agent to the antibiotic solution. The TC-HCl degradation efficiencies under PMS-activated system were calculated as 49.3% and 70% for BFO@PE and BFO/BNQDs@PE, respectively. The high-efficiency removal was assigned to the hindered recombination rate owing to electron capturing ability of PMS and quantum confinement effect of BNQDs. In addition, the immobilization of BFO/BNQDs particles on PE filter enabled more active surface sites for the target TC-HCl molecules, resulting enhanced photodegradation efficiency. The photocatalytic degradation mechanism was explained in detail and the reusability of catalytic filters was investigated. Under flow conditions, 91.3% removal was still achieved by BFO/BNQDs@PE catalytic filter until 7 h of visible light irradiation, verifying successful immobilization of BFO/BNQDs particles as well as its high reusability. This study contributes to the hybridization of quantum dots with scalable materials for treatment of recalcitrant pollutants with industrial interest.

Modification of polyester filters with synthesized copper nanoparticles for use as biocide in a real environment.

Antimicrobial air filtration techniques have recently been widely studied to enhance indoor air quality and mitigate hazardous airborne microorganisms. Here, CuNPs were incorporated into a commercial polyester fiber surface and Scanning Mobility Particle Sizer was used to measure the adherence between fibers and nanoparticles. An acid pretreatment previous CuNP incorporation was effective against the particle release and enhanced the adhesion between particle and fiber. CuNP was a mixture of Cu0 and Cu2O with a diameter size of 90 nm (SEM micrographs). The permeability of the filter was low, in order of 10–9 m2. The activity against pathogens was tested in loco in a real environment using a filtration prototype apparatus. It was observed that the presence of CuNP mitigated the fungi and bacteria growth not only on the surface but also reduced microbe concentrations after passing through the filter. These results show that CuNP can be used as an inhibitor of various microorganisms, making them a good alternative for indoor environments to control indoor air quality.

CuO-Coated Antibacterial and Antiviral Car Air-Conditioning Filters.

The demand for improved indoor air quality, especially during the pandemic of Covid-19, has led to renewed interest in antiviral and antibacterial air-conditioning systems. Here, air filters of vehicles made of nonwoven polyester filter media were sonochemically coated with CuO nanoparticles by a roll-to-roll coating method. The product, aimed at providing commuters with high air quality, showed good stability and mechanical properties and potent activity against Escherichia coli and Staphylococcus aureus bacteria, H1N1 influenza, and two SARS-CoV-2 variants. The filtering properties of a coated filter were tested, and they were similar to those of the uncoated filter. Leaching tests as a function of airflow were conducted, and the main outcome was that the coating was stable and particles were not detached from the coated media. Extension to other air-conditioning systems was straightforward.

Modification of the commercial polyester filter media support with electrospun polyethylene terephthalate fibers and its application for air purification

In this study, the electrospinning process modifies the commercial polyester filter media to increase filtration efficiency. The polyethylene terephthalate (PET) solution produces electrospun fiber on commercial polyester filter media at various rotation speeds and durations. The PET concentration and electrospinning applied voltage were adjusted accordingly to obtain bead-free electrospun fibers. As a result, the modified filter media’s filtration efficiency is approximately two times higher than the commercial polyester filter media at 300 rpm and 5 hours of electrospinning duration. Furthermore, the efficiency of the single unit modified filter media is 53.76% with an airflow resistance of 39.2 Pa and quality factor of 0.01968 Pa−1 which are comparable to the combination of two units’ air filters. Thus, replacing two units’ air filters having a primary and secondary filter with a single unit modified filter media is justifiable.

Relationship between intake and faecal excretion of indigestible fractions in trials with sheep: impact of the method of analysis, diet and trial

AbstractA data set of individual observations was compiled from 17 digestibility trials with sheep with the aim of evaluating the impact of the method of analysis and, within each method, the effect of dietary fibre content and trial on the faecal recovery rate (RR) of indigestible dry matter (iDM) and indigestible neutral detergent fibre (iNDF). Markers concentration in samples of diet and faeces were determined either in polyester filter bags of 40 μm of porosity incubated in situ for 144 h (method A; n = 257) or in bags of 16 μm of porosity incubated in situ for 288 h (method B; n = 321). Regardless of the incubation method, the intake of either iDM or iNDF was linearly (P < 0.05) related to the amount excreted in faeces and, for all linear relationships, the slopes were lower than 1 (i.e. between 0.53 and 0.71). Within both methods, the RR of both markers linearly decreased at increased NDF content in diet (P < 0.05). The root mean square error of the linear relationships varied from 0.147 to 0.189 which represented from 19% to 24% of the respective average RR of markers. In conclusion, regardless of the incubation method, the RR of both markers showed high individual variability and, thus, the use of average RR values obtained in controlled digestibility trials as an index to correct the individual digestibility values obtained with either marker in field trials has the potential to improve the accuracy but not the precision of the digestibility estimates.

Performance analysis of sheep wool fibres as a water filter medium for human enteric virus removal

Sheep wool is increasingly attracting interest for its applications in water and wastewater treatment because of its unique natural properties and superior environmental sustainability compared with non-renewable synthetic materials. While many studies' findings demonstrate wool's substantial capacity for absorbing heavy metals and organic contaminants from water and wastewater, little information is available describing its virus reduction capabilities during water filtration. This preliminary study examined scoured fine- and coarse- wool fibres regarding their abilities to remove human norovirus, adenovirus and rotavirus during water filtration. For each type of wool, 3 virus challenge experiments were conducted using wool-packed glass columns (30 cm long, 3.5 cm diameter) and bore water under a flow rate of 7.3–7.5 mL/s. The results from both wool types were very similar despite their different fibre sizes. The viruses showed greater reductions than the non-reactive water tracer, NaCl. The mass recovery ratios of the viruses to NaCl were 0.62–0.63 for norovirus, 0.64–0.65 for adenovirus and 0.40–0.42 for rotavirus. The log10 reduction values were 0.22–0.23, 0.21–0.22 and 0.45–0.52 for norovirus, adenovirus and rotavirus, respectively. Compared with previous studies' results, the virus reductions in wool appeared greater than those in polyester and polypropylene filters, and river sand. Our findings suggest that wool has some capacity to remove viruses during water filtration. With surface modifications to enhance its virus removal properties, wool has great potential as an alternative filter medium for treating point-of-use drinking water, especially in resourceless situations requiring practical solutions for accessing safe water.

Evaluation of a Polyester Filter and UV Light (PFUV) Dehumidifier to Improve Indoor Environmental Quality: Preliminary Results

Older residential dwellings in New Zealand frequently suffer from poor indoor environmental quality (IEQ) due to an ageing housing stock. Recent New Zealand surveys indicated around 50% of children live in houses that do not meet acceptable standards for thermal comfort. Children in these houses frequently experience respiratory conditions caused by dampness and mould during winter. New regulatory standards requiring a fixed heating source in the main living room of rental houses can increase rents and may result in the heating source not being utilized. This study evaluates an alternative low-cost portable air filter/sterilizer (PFUV) dehumidifier device for improving IEQ within the building envelope using Ultraviolet Germicidal Irradiation (UVGI) and a polyester filter (dual-10 30/30). This paper compares the effectiveness of the PFUV dehumidifier device and a conventional heat pump in terms of measured particulate matters as well as fungal profiles using Potato Dextrose Agar (PDA) plates. The PFUV dehumidifier successfully reduced the relative humidity to within a healthy range of (44–49%) compared to not running the device (54–60%), thereby reducing the suitability of the environment for mould growth. Additionally, the PFUV device achieved a reduction in average particulate matter (PM2.5) to within the range of 0.16 to 0.53 µg/m³ compared to the range of 1.06 to 2.42 µg/m³ before using the device.

Monitoring of Anaerobic Degradation in Batch Assays Using Fiber Bags

AbstractThe anaerobic batch digestion of freeze‐dried and ground (< 1.5 mm) maize silage, wheat straw, cattle manure, pig manure, and cellulose filter paper was investigated with substrates placed in polyester filter bags. Gas production dynamics of bagged and non‐bagged substrates were compared. By using batch bottles running in parallel with those used for gas measurement, substrates could be sampled over time and various parameters measured for both substrate and bulk liquid. The bags allowed an immediate mass loss into the bulk liquid with some substrates and a generally lower rate of gas production. This method requires refinement but has potential for the study of the dynamics of substrate degradation during anaerobic digestion.