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1.
Sci Rep ; 14(1): 9089, 2024 04 20.
Article in English | MEDLINE | ID: mdl-38643225

ABSTRACT

Patients in intensive care are exposed to the risk of microparticle infusion via extracorporeal lines and the resulting complications. A possible source of microparticle release could be the extracorporeal circuit used in blood purification techniques, such as continuous renal replacement therapy (CRRT). Disposable components of CRRT circuits, such as replacement bags and circuit tubing, might release microparticles such as salt crystals produced by precipitation in replacement bags and plastic microparticles produced by spallation. In-line filtration has proven effective in retaining microparticles both in in-vitro and in-vivo studies. In our study, we performed an in-vitro model of CRRT-treatment with the aim of detecting the microparticles produced and released into the circuit by means of a qualitative and quantitative analysis, after sampling the replacement and patient lines straddling a series of in-line filters. Working pressures and flows were monitored during the experiment. This study showed that microparticles are indeed produced and released into the CRRT circuit. The inclusion of in-line filters in the replacement lines allows to reduce the burden of microparticles infused into the bloodstream during extracorporeal treatments, reducing the concentration of microparticles from 14 mg/mL pre in-line filter to 11 mg/mL post in-line filter. Particle infusion and related damage must be counted among the pathophysiological mechanisms supporting iatrogenic damage due to artificial cross-talk between organs during CRRT applied to critically ill patients. This damage can be reduced by using in-line filters in the extracorporeal circuit.


Subject(s)
Continuous Renal Replacement Therapy , Extracorporeal Membrane Oxygenation , Humans , Extracorporeal Membrane Oxygenation/methods , Filtration , Pressure
2.
Water Sci Technol ; 89(7): 1630-1646, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38619894

ABSTRACT

Due to the colloidal stability, the high compressibility and the high hydration of extracellular polymeric substances (EPS), it is difficult to efficiently dehydrate sludge. In order to enhance sludge dewatering, the process of ultrasonic (US) cracking, chitosan (CTS) re-flocculation and sludge-based biochar (SBB) skeleton adsorption of water-holding substances to regulate sludge dewaterability was proposed. Based on the response surface method, the prediction model of the specific resistance to filtration (SRF) and sludge cake moisture content (MC) was established. The US cracking time and the dosage of CTS and SBB were optimized. The results showed that the optimal parameters of the three were 5.08 s, 10.1 mg/g dry solids (DS) and 0.477 g/g DS, respectively. Meantime, the SRF and MC were 5.4125 × 1011 m/kg and 76.8123%, which significantly improved the sludge dewaterability. According to the variance analysis, it is found that the fitting degree of SRF and MC model is good, which also confirms that there is significant interaction and synergy between US, CTS and SBB, and the contribution of CTS and SBB is greater. Moreover, the process significantly improves the sludge's calorific value and makes its combustion more durable.


Subject(s)
Chitosan , Sewage , Ultrasonics , Charcoal , Filtration , Water , Waste Disposal, Fluid/methods
3.
Environ Monit Assess ; 196(5): 476, 2024 Apr 25.
Article in English | MEDLINE | ID: mdl-38662019

ABSTRACT

The ingestion of Ti-containing nanoparticles from drinking water has emerged as a concern in recent years. This study therefore aimed to characterize Ti-containing nanoparticles in water samples collected from four water treatment plants in Taiwan and to explore the challenges associated with measuring them at low levels using single particle-inductively coupled plasma mass spectrometry. Additionally, the study sought to identify the most effective processes for the removal of Ti-containing nanoparticles. For each water treatment plant, two water samples were collected from raw water, sedimentation effluent, filtration effluent, and finished water, respectively. Results revealed that Ti-containing nanoparticles in raw water, with levels at 8.69 µg/L and 296.8 × 103 particles/L, were removed by approximately 35% and 98%, respectively, in terms of mass concentration and particle number concentration, primarily through flocculation and sedimentation processes. The largest most frequent nanoparticle size in raw water (112.0 ± 2.8 nm) was effectively reduced to 62.0 ± 0.7 nm in finished water, while nanoparticles in the size range of 50-70 nm showed limited changes. Anthracite was identified as a necessary component in the filter beds to further improve removal efficiency at the filtration unit. Moreover, the most frequent sizes of Ti-containing nanoparticles were found to be influenced by salinity. Insights into the challenges associated with measuring low-level Ti-containing nanoparticles in aqueous samples provide valuable information for future research and management of water treatment processes, thereby safeguarding human health.


Subject(s)
Titanium , Water Pollutants, Chemical , Water Purification , Taiwan , Water Purification/methods , Water Pollutants, Chemical/analysis , Environmental Monitoring , Metal Nanoparticles , Filtration , Drinking Water/chemistry
4.
J Exp Biol ; 227(8)2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38629316

ABSTRACT

Filter-feeding demosponges are modular organisms that consist of modules each with one water-exit osculum. Once a mature module has been formed, the weight-specific filtration and respiration rates do not change. Sponge modules only grow to a certain size and for a sponge to increase in size, new modules must be formed. However, the growth characteristics of a small single-osculum module sponge are fundamentally different from those of multi-modular sponges, and a theoretically derived volume-specific filtration rate scales as F/V=V-1/3, indicating a decrease with increasing total module volume (V, cm3). Here, we studied filtration rate (F, l h-1), respiration rate (R, ml O2 h-1), volume-specific (F/V) and weight-specific (F/W) filtration rates, and the ratios F/R and F/W along with growth rates of small single-osculum demosponge Halichondria panicea explants of various sizes exposed to various concentrations of algal cells. The following relationships were found: F/V=7.08V-0.24, F=a1W1.05, and R=a2W0.68 where W is the dry weight (mg). The F/R and F/W ratios were constant and essentially independent of W, and other data indicate exponential growth. It is concluded that the experimental data support the theoretical F/V∝V-1/3.


Subject(s)
Porifera , Water , Animals , Respiration , Filtration , Respiratory Rate
5.
Sci Rep ; 14(1): 8830, 2024 04 17.
Article in English | MEDLINE | ID: mdl-38632265

ABSTRACT

Face masks are essential in reducing the transmission of respiratory infections and bacterial filtration efficiency, a key parameter of mask performances, requires the use of Staphylococcus aureus and specialised staff. This study aims to develop a novel method for a preliminary screening of masks or materials filtration efficiency by a green, easy and rapid setup based on the use of a riboflavin solution, a safe autofluorescent biomolecule. The proposed setup is composed of a commercial aerosol generator commonly used for aerosol therapy, custom 3D printed aerosol chamber and sample holder, a filter for downstream riboflavin detection and a vacuum pump. The filtration efficiency of four different masks was assessed using the riboflavin-based setup and the bacterial filtration efficiency (BFE). The averaged filtration efficiency values, measured with both methods, were similar but were higher for the riboflavin-based setup (about 2% for all tested samples) than bacterial filtration efficiency. Considering the good correlation, the riboflavin-based setup can be considered validated as an alternative method to bacterial filtration efficiency for masks and related materials fabrics filtration efficiency screening but This study aims to develop a novel method for a preliminary screening of masks or materials filtration efficiency by a green, easy and rapid setup based on the use of a riboflavin solution, a safe autofluorescent biomolecule, but not to replace regulation approaches. The proposed setup can be easily implemented at low price, is more rapid and eco-friendly and can be performed in chemical-physical laboratories without the needing of biosafety laboratory and specialised operators.


Subject(s)
Masks , Respiratory Protective Devices , Humans , Respiratory Aerosols and Droplets , Filtration , Aerosols
6.
Bioinspir Biomim ; 19(3)2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38579733

ABSTRACT

African shrimp (Atya gabonensis) inhabit clear freshwaters, where the notably low concentration of food may pose a challenge to the efficacy of filter fibers on the chela for filter-feeding. Here, we investigate how the distinctive cross-sectional characteristics and spatial arrangement of the African shrimp's non-circular fibers contribute to the enhanced filtration performance of these specialized fibers. The unilateral thickening of the wall along the long axis of the elliptical cross-section of African shrimp fibers markedly enhances the filtration performance. The staggered and twisted arrangement of the fibers optimizes the surrounding flow field, achieving a favorable balance between pressure drop and collection efficiency, consequently improving their filtration performance in collecting fine particles (diameter: 2-10µm). Moreover, the arrangement of the fibers substantially increases the effective flow-facing filtering area of the fiber bundles, thus facilitating their efficiency in collecting larger particles (diameter > 10µm). The unique fiber properties of the African shrimp offer novel insights for the design and optimization of new fiber-filtering robots, presenting a wide range of potential applications, such as marine in-situ resource extraction, medical filtration, and industrial filtration.


Subject(s)
Filtration , Cross-Sectional Studies
7.
J Environ Manage ; 357: 120824, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38583379

ABSTRACT

Extending the solids retention time (SRT) has been demonstrated to mitigate membrane biofouling. Nevertheless, it remains an intriguing question whether the compact and water flushing resistant mesh biofilms developed at short SRT can undergo biodegradation and be removed with extended SRT. In present study, the bio-fouled mesh filter in the 10d-SRT dynamic membrane bioreactor (DMBR), with mesh surfaces and pores covered by compact and water flushing resistant biofilms exhibiting low water permeability, was reused in the 40d-SRT DMBR without any cleanings. After being reused at 40d-SRT, its flux driven by gravity occurred from the 10th day and recovered to a regular level of 36.7 L m-2·h-1 on the 27th day. Both scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) analyses indicated that the compact mesh biofilms formed at10d-SRT biodegraded and were removed at 40d-SRT, with the residual biofilms becoming removable by water flushing. As a result, the hydraulic resistance of the bio-fouled mesh filter decreased from 4.36 × 108 to 6.97 × 107 m-1, and its flux fully recovered. The protein and polysaccharides densities in mesh-biofilms decreased from 24.4 to 9.7 mg/cm2 and from 10.7 to 0.10 mg/cm2, respectively, which probably have contributed to the disappearance of compact biofilms and the decrease in adhesion. Furthermore, the sludge and mesh-biofilms in the 40d-SRT reactor contained a higher relative abundance of dominant quorum quenching bacteria, such as Rhizobium (3.52% and 1.35%), compared to those in the 10d-SRT sludge (0.096%) and mesh biofilms (0.79%), which might have been linked to a decline in extracellular polymeric substances and, consequently, the biodegradation and disappearance of compact biofilms.


Subject(s)
Biofouling , Sewage , Biofilms , Biofouling/prevention & control , Filtration , Bioreactors/microbiology , Membranes, Artificial
8.
Int J Pharm Compd ; 28(2): 120-127, 2024.
Article in English | MEDLINE | ID: mdl-38604149

ABSTRACT

The great majority of sterile products commercially available as well as prepared in compounding pharmacies are sterilized by sterile filtration during aseptic processing. This brief and basic review will highlight the nature, action, and use of sterilizing filters. Special emphasis is given to how filters are validated in producing a sterile filtrate while being compatible with the filtered solution, as well as how filters are integrity tested during aseptic processing.


Subject(s)
Filtration , Pharmacies , Sterilization
9.
PDA J Pharm Sci Technol ; 78(2): 196-205, 2024.
Article in English | MEDLINE | ID: mdl-38609151

ABSTRACT

Session 7 of the 2023 Viral Clearance Symposium reviewed progresses in virus retentive filtrations applied to both upstream and downstream processing. Upstream topics included investigations and applications of media viral filtration for upstream cell culture viral risk mitigation. Downstream topics included evaluation of viral breakthrough in continuous processing using surrogate particles and demonstration of extensive viral filtration cycling with flow interruptions and long duration in connected process. Reuse of viral filters with proposed procedures was successfully demonstrated amid the supply chain challenge encountered during the pandemic. Discussions and additional considerations for the topics were also provided.


Subject(s)
Cell Culture Techniques , Filtration , Kinetics , Pandemics
10.
PDA J Pharm Sci Technol ; 78(2): 141-143, 2024.
Article in English | MEDLINE | ID: mdl-38609152

ABSTRACT

The 2023 Viral Clearance Symposium (VCS) was hosted by Takeda on 24 and 25 May 2023 in Vienna, Austria. The present conference extended the structure of the previous biennial symposia held between 2009 and 2019. As recapitulated in the introductory session, the genesis of the VCS, as described in the Proceedings of the 2009 VCS was "the worldwide regulatory and industry recognition that challenges, gaps, and opportunities exist, that it formally addressed could benefit the field as whole." This report provides a synopsis of the progress achieved at the conference resulting from detailed technical discussions and the pending questions that still require attention to address. The 2023 VCS was composed of nine individual sessions of short presentations followed by in-depth panel discussions from the presenters. Sessions included Regulatory Updates (with a focus on ICH Q5A(R2) efforts), including a summary of lessons learned from the 2019 VCS, and progress on these key areas mapped into 2023 VCS topics: Viral Clearance Strategy and Case Studies, New Modalities in Chromatography and Adsorptive Filters, Continuous Processing, Viral Clearance Strategy and Process Understanding, Virus Inactivation, Upstream and Downstream Virus Retentive Filtration and Cell Banks, and Advanced Technologies (advanced therapy medicinal products, next-generation sequencing).


Subject(s)
Filtration , High-Throughput Nucleotide Sequencing , Adsorption , Industry , Kinetics
11.
Article in English | MEDLINE | ID: mdl-38571317

ABSTRACT

Two cost-effective packing materials were used for n-butyl acetate removal in lab-scale biofilters, namely waste spruce root wood chips and biochar obtained as a byproduct from a wood gasifier. Three biofilters packed with spruce root wood chips: without biochar (SRWC), a similar one with 10% of biochar (SRWC-B) and that with 10% of biochar impregnated with a nitrogen fertilizer (SRWC-IB) showed similar yet differing maximum elimination capacities of 206 ± 27, 275 ± 21 and 294 ± 20 g m-3 h-1, respectively, enabling high pollutant removal efficiency (>95% at moderate loads) and stable performance. The original biochar adsorption capacity was high (208 ± 6 mgtoluene g-1), but near 70% of it was lost after a 300-day biofilter operation. By contrast, the exposed impregnated biochar drastically increased its adsorption capacity in 300 days (149 ± 7 vs. 17 ± 5 mgtoluene g-1). Colony forming unit (CFU) and microscopic analyses revealed significant packing material colonization by microorganisms and grazing fauna in all three biofilters with an acceptable pressure drop, up to 1020 Pa m-1, at the end of biofilter operation. Despite a higher price (14 vs. 123 €m-3), the application of the best performing SRWC-IB packing can reduce the total investment costs by 9% due to biofilter volume reduction.


Subject(s)
Acetates , Charcoal , Filtration , Toluene , Biodegradation, Environmental
12.
Invest Ophthalmol Vis Sci ; 65(3): 6, 2024 Mar 05.
Article in English | MEDLINE | ID: mdl-38466285

ABSTRACT

Purpose: Isolating extracellular vesicles (EVs) with high yield, replicable purity, and characterization remains a bottleneck in the development of EV therapeutics. To address these challenges, the current study aims to establish the necessary framework for preclinical and clinical studies in the development of stem cell-derived intraocular EV therapeutics. Methods: Small EVs (sEVs) were separated from the conditioned cell culture medium (CCM) of the human embryogenic stem cell-derived fully polarized retinal pigment epithelium (hESC-RPE-sEV) by a commercially available microfluidic tangential flow filtration (TFF) device ExoDisc (ED) or differential ultracentrifugation (dUC). The scaling and concentration capabilities and purity of recovered sEVs were assessed. Size, number, and surface markers of sEVs were determined by orthogonal approaches using multiple devices. Results: ED yielded higher numbers of sEVs, ranging from three to eight times higher depending on the measurement device, compared to dUC using the same 5 mL of CCM input. Within the same setting, the purity of ED-recovered hESC-RPE-sEVs was higher than that for dUC-recovered sEVs. ED yielded a higher concentration of particles, which is strongly correlated with the input volume, up to 10 mL (r = 0.98, P = 0.016). Meanwhile, comprehensive characterization profiles of EV surface markers between ED- and dUC-recovered hESC-RPE-sEVs were compatible. Conclusions: Our study supports TFF as a valuable strategy for separating sEVs for the development of intraocular EV therapeutics. However, there is a growing need for diverse devices to optimize TFF for use in EV preparation. Using orthogonal approaches in EV characterization remains ideal for reliably characterizing heterogeneous EV.


Subject(s)
Extracellular Vesicles , Human Embryonic Stem Cells , Humans , Culture Media, Conditioned , Filtration , Retinal Pigment Epithelium
13.
Biotechnol J ; 19(3): e2300348, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38472091

ABSTRACT

The development and manufacture of biopharmaceuticals are subject to strict regulations that specify the required minimum quality of the products. A key measure to meet these quality requirements is the integration of a sterile filtration step into the commercial manufacturing process. Whereas common procedures for most biologics exist, this is challenging for lentiviral vector (LVV) production for ex vivo gene therapy. LVVs nominal size is more than half the pore size (0.2 µm) of filters used for sterile filtration. Hence, highly concentrated virus solutions are prone to filter clogging if aggregation of viruses occurs or impurities attach to the viruses. Several filters were screened aiming to identify those which allow filtering highly concentrated stocks of LVVs of up to 1E + 9 transducing units mL-1 , which corresponds to 4.5E + 12 particles mL-1 . In addition, the effect of endonuclease treatment upstream of the purification process on filter performance was studied. In summary, three suitable filters were identified in a small-scale study (<15 mL) with virus yields >80% and the process was successfully scaled-up to a final scale of 100 mL LVV stock solution.


Subject(s)
Lentivirus , Viruses , Lentivirus/genetics , Viruses/genetics , Filtration/methods , Genetic Therapy
14.
Electromagn Biol Med ; 43(1-2): 107-116, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38461462

ABSTRACT

Exposure to blue light at bedtime, suppresses melatonin secretion, postponing the sleep onset and interrupting the sleep process. Some smartphone manufacturers have introduced night-mode functions, which have been claimed to aid in improving sleep quality. In this study, we evaluate the impact of blue light filter application on decreasing blue light emissions and improving sleep quality. Participants in this study recorded the pattern of using their mobile phones through a questionnaire. In order to evaluate sleep quality, we used a PSQI questionnaire. Blue light filters were used by 9.7% of respondents, 9.7% occasionally, and 80% never. The mean score of PSQI was more than 5 in 54.10% of the participants and less than 5 in 45.90%. ANOVA test was performed to assess the relationship between using blue light filter applications and sleep quality (p-value = 0.925). The findings of this study indicate a connection between the use of blue light filter apps and habitual sleep efficiency in the 31-40 age group. However, our results align only to some extent with prior research, as we did not observe sustained positive effects on all parameters of sleep quality from the long-term use of blue light filtering apps. Several studies have found that blue light exposure can suppress melatonin secretion, exacerbating sleep problems. Some studies have reported that physical blue light filters, such as lenses, can affect melatonin secretion and improve sleep quality. However, the impact of blue light filtering applications remains unclear and debatable.


Using smartphones before bedtime and being exposed to its blue light can make it harder to fall asleep and disrupt your sleep. Some smartphone makers have introduced a night mode feature claiming it can help improve your sleep. In this study, we wanted to find out if using these blue light filters on smartphones really makes a difference. We asked people how often they used blue light filters on their phones and also had them fill out a questionnaire about their sleep quality. Only about 10% of people said they used blue light filters regularly, another 10% used them occasionally, and the majority, around 80%, never used them. When we looked at the results, more than half of the participants had sleep scores higher than 5, indicating they might have sleep problems. Less than half had sleep scores lower than 5, suggesting better sleep quality. We used some statistical tests to see if using blue light filters had any link to sleep quality, and the results showed that there was only a connection between the use of blue light filter apps and habitual sleep efficiency in the 31­40 age group. Our findings matched what other studies have found before, that using blue light filters on smartphones may not significantly help improve sleep. So, while it might be a good idea to limit smartphone use before bed, using a blue light filter app may not be the magic solution for better sleep.


Subject(s)
Light , Sleep Quality , Smartphone , Humans , Adult , Male , Female , Mobile Applications , Color , Surveys and Questionnaires , Sleep/physiology , Sleep/radiation effects , Filtration/instrumentation , 60440
15.
J Emerg Med ; 66(4): e477-e482, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38433037

ABSTRACT

BACKGROUND: Medical equipment can become scarce in disaster scenarios. Prior work has reported that four sheep could be ventilated together on a single ventilator. Others found that this maneuver is possible when needed, but no one has yet investigated whether cross-contamination occurs in co-ventilated individuals. OBJECTIVE: Our goal was to investigate whether an infection could spread between co-ventilated individuals. METHODS: Four 2-L anesthesia bags were connected to a sterilized ventilator circuit that used heat and moisture exchange filters and bacterial and viral filters, as would be expected in this dire scenario. Serratia marcescens was inoculated into "lung" no. 1. After running for 24 h, each lung and three additional points in the circuit were cultured to see whether S. marcescens had spread. These cultures were examined at 24 and 48 h to assess for cross-contamination. This entire procedure was performed three times. RESULTS: S. marcescens was not found in lung no. 2, 3, or 4 or the three additional sites on the expiratory limb at 24 and 48 h in all three trials. CONCLUSIONS: Cross-contamination does not occur within 24 h using the described ventilator circuit configuration.


Subject(s)
Equipment Contamination , Ventilators, Mechanical , Humans , Bacteria , Filtration , Lung , Respiration, Artificial
16.
Chemosphere ; 355: 141818, 2024 May.
Article in English | MEDLINE | ID: mdl-38548085

ABSTRACT

Skeleton builders were normally deemed to improve the high porosity and newly-generated permeability of sludge cakes by building water transfer channel during high pressure filtration, thus enhancing sludge dewaterability. However, currently a direct visualization proof of water transfer channel was still lacking. This study provided the direct proof for visualizing water transfer channel in dewatered sludge cakes conditioned with a typical skeleton builder (i.e., phosphogypsum (PG)) by X-ray micro-computed tomography (micro-CT) for the first time. After the addition of PG, the pixel value and image luminance increased significantly, indicating the presence of high density substances from both two-dimensional (2D) cross section and three-dimensional (3D) reconstruction CT images. Moreover, the CT numbers showed strong and negative correlations with specific resistance to filtration (SRF) (R = - 0.99, p < 0.05), capillary suction time (CST) (regression coefficient (R) = - 0.87, probability (p) < 0.05), and water content of the dewatered sludge cake (R = - 0.99, p < 0.05), respectively. These results indicated that the X-ray micro-CT could be a potential technique for analyzing the water distribution in sludge samples conditioned with skeleton builders.


Subject(s)
Calcium Sulfate , Filtration , Phosphorus , Sewage , X-Ray Microtomography , Water , Skeleton , Waste Disposal, Fluid/methods
17.
Environ Sci Technol ; 58(14): 6181-6191, 2024 Apr 09.
Article in English | MEDLINE | ID: mdl-38536729

ABSTRACT

Flow-electrode capacitive deionization (FCDI) is a promising technology for sustainable water treatment. However, studies on the process have thus far been limited to lab-scale conditions and select fields of application. Such limitation is induced by several shortcomings, one of which is the absence of a comprehensive process model that accurately predicts the operational performance and the energy consumption of FCDI. In this study, a simulation model is newly proposed with initial validation based on experimental data and is then utilized to elucidate the performance and the specific energy consumption (SEC) of FCDI under multiple source water conditions ranging from near-groundwater to high salinity brine. Further, simulated pilot-scale FCDI system was compared with actual brackish water reverse osmosis (BWRO) and seawater reverse osmosis (SWRO) plant data with regard to SEC to determine the feasibility of FCDI as an alternative to the conventional membrane processes. Analysis showed that FCDI is competent for operation against brackish water solutions under all possible operational conditions with respect to the BWRO. Moreover, its distinction can be extended to the SWRO for seawater conditions through optimization of its total effective membrane area via scale-up. Accordingly, future directions for the advancement of FCDI was suggested to ultimately prompt the commercialization of the FCDI process.


Subject(s)
Sodium Chloride , Water Purification , Filtration , Electrodes , Seawater
18.
J Hazard Mater ; 469: 134064, 2024 May 05.
Article in English | MEDLINE | ID: mdl-38513444

ABSTRACT

Water vapor from respiration can severely accelerate the charge dissipation of the face mask, reducing filtration efficiency. Moreover, the foul odor from prolonged mask wear tends to make people remove their masks, leading to the risk of infection. In this study, an electro-blown spinning electroactive nanofibrous membrane (Zn/CB@PAN) with antibacterial and deodorization properties was prepared by adding zinc (Zn) and carbon black (CB) nanoparticles to the polyacrylonitrile (PAN) nanofibers, respectively. The filtration efficiency of Zn/CB@PAN for PM0.3 was > 99% and could still maintain excellent durability within 4 h in a high-humidity environment (25 â„ƒ and RH = 95%). Moreover, the bacterial interception rate of the Zn/CB@PAN could reach 99.99%, and it can kill intercepted bacteria. In addition, the deodorization rate of Zn/CB@PAN in the moist state for acetic acid was 93.75% and ammonia was 95.23%, respectively. The excellent filtering, antibacterial, and deodorizing performance of Zn/CB@PAN can be attributed to the synergistic effect of breath-induced Zn/CB galvanic couples' electroactivity, released metal ions, and generated reactive oxygen species. The developed Zn/CB@PAN could capture and kill airborne environmental pathogens under humid environments and deodorize odors from prolonged wear, holding promise for broad applications as personal protective masks.


Subject(s)
Nanofibers , Humans , Anti-Bacterial Agents , Acetic Acid , Zinc , Ammonia , Filtration
19.
Water Res ; 254: 121383, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38432002

ABSTRACT

The gravity-driven membrane (GDM) system is desirable for energy-efficient water treatment. However, little is known about the influence of cations on biofilm properties and GDM performance. In this study, typical cations (Ca2+ and Na+) were used to reveal the combined fouling behavior and mechanisms. Results showed that Ca2+ improved the stable flux and pollutant removal efficiency, while Na+ adversely affected the flux. Compared with GDM control, the concentration of pollutants was lower in Ca-GDM, as indicated by the low biomass, proteins, and polysaccharides. A heterogeneous and loose biofilm was observed in the Ca-GDM system, with roughness and porosity increasing by 43.06 % and 32.60 %, respectively. However, Na+ induced a homogeneous and dense biofilm, with porosity and roughness respectively reduced by 17.48 % and 22.04 %. The richness of bacterial communities increased in Ca-GDM systems, while it decreased in Na-GDM systems. High adenosine triphosphate (ATP) concentration in Ca-GDM system was consistent with the abundant bacteria and their high biological activity, which was helpful for the efficient removal of pollutants. The abundance of Apicomplexa, Platyhelminthes, Annelida and Nematoda increased after adding Ca2+, which was related to the formation of loose biofilms. Computational simulations indicated that the free volumes of the biofilms in Ca-GDM and Na-GDM were 13.7 and 13.2 nm3, respectively. The addition of cations changed intermolecular forces, Ca2+ induced bridging effects led to large and loose floc particles, while the significant dehydration of hydrated molecules in the Na-GDM caused obvious aggregation. Overall, microbiological characteristics and contaminant molecular interactions were the main reasons for differences in GDM systems.


Subject(s)
Environmental Pollutants , Water Purification , Membranes, Artificial , Filtration/methods , Biofilms , Water Purification/methods , Cations
20.
Environ Sci Technol ; 58(13): 5878-5888, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38498471

ABSTRACT

Data-driven machine learning (ML) provides a promising approach to understanding and predicting the rejection of trace organic contaminants (TrOCs) by polyamide (PA). However, various confounding variables, coupled with data scarcity, restrict the direct application of data-driven ML. In this study, we developed a data-knowledge codriven ML model via domain-knowledge embedding and explored its application in comprehending TrOC rejection by PA membranes. Domain-knowledge embedding enhanced both the predictive performance and the interpretability of the ML model. The contribution of key mechanisms, including size exclusion, charge effect, hydrophobic interaction, etc., that dominate the rejections of the three TrOC categories (neutral hydrophilic, neutral hydrophobic, and charged TrOCs) was quantified. Log D and molecular charge emerge as key factors contributing to the discernible variations in the rejection among the three TrOC categories. Furthermore, we quantitatively compared the TrOC rejection mechanisms between nanofiltration (NF) and reverse osmosis (RO) PA membranes. The charge effect and hydrophobic interactions possessed higher weights for NF to reject TrOCs, while the size exclusion in RO played a more important role. This study demonstrated the effectiveness of the data-knowledge codriven ML method in understanding TrOC rejection by PA membranes, providing a methodology to formulate a strategy for targeted TrOC removal.


Subject(s)
Nylons , Water Purification , Osmosis , Water Purification/methods , Membranes, Artificial , Filtration
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