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1.
BMC Nephrol ; 25(1): 314, 2024 Sep 20.
Article in English | MEDLINE | ID: mdl-39304801

ABSTRACT

We are writing to you in response to the article published in BMC Nephrology titled "Dose of nafamostat mesylate during continuous kidney replacement therapy in critically ill patients: a two-centre observational study". The study provided valuable information on the use of nafamostat mesylate (NM) during continuous renal replacement therapy (CRRT) in critically ill patients. We noticed in this study that a higher dose of NM resulted in a decrease in ICU and hospital mortality. However, the underlying mechanism behind this phenomenon remains unclear. We believe exploring this further is warranted.


Subject(s)
Benzamidines , Critical Illness , Guanidines , Humans , Critical Illness/therapy , Guanidines/therapeutic use , Continuous Renal Replacement Therapy , Membranes, Artificial , Adsorption , Acute Kidney Injury/therapy , Renal Replacement Therapy
2.
Infect Dis (Lond) ; : 1-9, 2024 Aug 16.
Article in English | MEDLINE | ID: mdl-39150281

ABSTRACT

BACKGROUND: India relies primarily on direct smear microscopy for tuberculosis (TB) diagnosis. However, the low sensitivity of smear microscopy emphasizes the need to improve its performance. We recently described the development of 'TBDetect' kit which showed improved performance over direct smear microscopy at National Reference Laboratories (NRLs) in India. METHODS: The present study was aimed to assess the operational feasibility of 'TBDetect' microscopy in field settings. This was evaluated by (i) assessing the performance of 'TBDetect' microscopy vs. LED-fluorescence microscopy (LED-FM) on consecutive presumptive pulmonary TB patients (n = 5300) who attended Designated Microscopy Centres (DMCs, n = 13) under 4 NRLs at Bhubaneswar, Bhopal, Chennai, and New Delhi, and (ii) obtaining feedback from Scientists (n = 10) and laboratory technicians (n = 42) using semi-structured questionnaires under the following parameters: feasibility of initiation of 'TBDetect' microscopy in DMCs, sample preparation and testing, training, time-to-result, logistics, and troubleshooting. A scoring questionnaire was also used to assess 'TBDetect' microscopy vs. LED-FM and statistical significance of the scores was calculated using paired t-test. RESULTS: The overall positivity of 'TBDetect' microscopy was 10.32% (547/5300) vs. 8.96% (475/5300) of LED-FM at all sites and the increment in positivity was significant (p = 0.019). In addition, 'TBDetect' microscopy yielded an increment in smear grade status over LED-FM (p = 0.043). The feedback from the study-in-charge and kit users indicated that 'TBDetect' microscopy was easily adapted in point-of-care settings. An analysis of scoring feedback suggested that it was easy to perform and observe in comparison to LED-FM (p < 0.005). CONCLUSIONS: This study established the feasibility of 'TBDetect' microscopy in field settings.

3.
Front Microbiol ; 15: 1339844, 2024.
Article in English | MEDLINE | ID: mdl-38855767

ABSTRACT

DNA extraction yield from drinking water distribution systems and premise plumbing is a key metric for any downstream analysis such as 16S amplicon or metagenomics sequencing. This research aimed to optimize DNA yield from low-biomass (chlorinated) reverse osmosis-produced tap water by evaluating the impact of different factors during the DNA extraction procedure. The factors examined are (1) the impact of membrane materials and their pore sizes; (2) the impact of different cell densities; and (3) an alternative method for enhancing DNA yield via incubation (no nutrient spiking). DNA from a one-liter sampling volume of RO tap water with varying bacterial cell densities was extracted with five different filter membranes (mixed ester cellulose 0.2 µm, polycarbonate 0.2 µm, polyethersulfone 0.2 and 0.1 µm, polyvinylidene fluoride 0.1 µm) for biomass filtration. Our results show that (i) smaller membrane pore size solely did not increase the DNA yield of low-biomass RO tap water; (ii) the DNA yield was proportional to the cell density and substantially dependent on the filter membrane properties (i.e., the membrane materials and their pore sizes); (iii) by using our optimized DNA extraction protocol, we found that polycarbonate filter membrane with 0.2 µm pore size markedly outperformed in terms of quantity (DNA yield) and quality (background level of 16S gene copy number) of recovered microbial DNA; and finally, (iv) for one-liter sampling volume, incubation strategy enhanced the DNA yield and enabled accurate identification of the core members (i.e., Porphyrobacter and Blastomonas as the most abundant indicator taxa) of the bacterial community in low-biomass RO tap water. Importantly, incorporating multiple controls is crucial to distinguish between contaminant/artefactual and true taxa in amplicon sequencing studies of low-biomass RO tap water.

4.
Nanomaterials (Basel) ; 14(11)2024 May 22.
Article in English | MEDLINE | ID: mdl-38869536

ABSTRACT

With the intensification of global climate problems, electric heating has recently attracted much attention as a clean and low-carbon heating method. Carbon nanotubes (CNTs) are an ideal medium for electric heating applications due to their excellent mechanical, electrical, and thermal properties. The preparation of electrothermal films based on an aqueous CNT dispersion as a raw material is environmentally friendly. However, in the traditional one-step filtration method, the residual excess dispersant and the small aspect ratio of the CNTs in the preparation process limit the performance of electrothermal CNT films. In this paper, we report a two-step filtration method that removes the free dispersant and small CNTs in the first filtration step and obtains denser CNT films by controlling the pores of the filter membrane in the second filtration step. The results suggest that, compared to the CNT1 film obtained from one-step filtration, the CNT1-0.22 film, obtained from two-step filtration using 1 and 0.22 µm membranes, has a smoother and flatter surface, and the surface resistance is 80.0 Ω sq-1, which is 29.4% lower. The convective radiation conversion efficiency of the CNT1-0.22 film is 3.36 mW/°C, which is 36.1% lower. We anticipate that such CNT films could be widely applied in building thermal insulation and underfloor heating.

5.
Polymers (Basel) ; 16(9)2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38732709

ABSTRACT

This paper reports the successful fabrication of a new nanofibrous membrane, F-PI/PAN, through electrospinning of polyacrylonitrile (PAN) and fluorinated polyimide (F-PI). The nanofibrous membrane exhibits comprehensive properties for high-temperature filtration and robust PM2.5 (particulate matter with an aerodynamic equivalent diameter of 2.5 microns or less) removal. The introduction of F enhances the hydrophobicity of the PI. The relationship between the hydrophobic performance and the filtration performance of particles is investigated. The chemical group of the composite membrane was demonstrated using FITR, while the surface morphology was investigated using field emission scanning electron microscopy. The TGA results indicated good thermal stability at 300 °C. Various ratios of F-PI membranes were prepared to characterize the change in properties, with the optimal mass ratio of F-PI being 20 wt%. As the proportion of F-PI increases, its mechanical and filtration efficiency properties and hydrophobicity become stronger. The contact angle reaches its maximum of 128 ± 5.2° when PAN:F-PI = 6:4. Meanwhile, when PAN:F-PI = 8:2, the filtration efficiency reaches 99.4 ± 0.3%, and the elongation at break can reach 76%. The fracture strength can also reach 7.1 MPa, 1.63 times that of the pure PAN membrane.

6.
J Hazard Mater ; 474: 134740, 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-38805821

ABSTRACT

Construction of air filter membranes bearing prominent collecting and transferring capability is highly desirable for detecting airborne pathogens but remains challenging. Here, a hyaluronic acid air filter membrane (HAFM) with tunable heterogeneous micro-nano porous structures is straightforwardly constructed through the ethanol-induced phase separation strategy. Airborne pathogens can be trapped and collected by HAFM with high performance due to the ideal trade-off between removal efficiency and pressure drop. By exempting the sample elution and extraction processes, the HAFM after filtration sampling can not only directly disperse on the agar plate for colony culture but also turn to an aqueous solution for centrifugal enrichment, which significantly reduces the damage and losses of the captured microorganisms. The following combination with ATP bioluminescence endows the HAFM with a real-time quantitative detection function for the captured airborne pathogens. Benefiting from high-efficiency sampling and non-traumatic transfer of airborne pathogens, the real-world bioaerosol concentration can be facilely evaluated by the HAFM-based ATP assay. This work thus not only provides a feasible strategy to fabricate air filter membranes for efficient microbial collection and enrichment but also sheds light on designing advanced protocols for real-time detection of bioaerosols in the field.


Subject(s)
Air Filters , Air Microbiology , Membranes, Artificial , Air Filters/microbiology , Filtration/instrumentation , Aerosols/analysis , Environmental Monitoring/methods , Adenosine Triphosphate/analysis , Bacteria/isolation & purification
7.
Anal Chim Acta ; 1292: 342233, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38309850

ABSTRACT

BACKGROUND: Label-free surface-enhanced Raman spectroscopy (SERS)-based metabolic profiling has great potential for early cancer diagnosis, but further advancements in analytical methods and clinical evidence studies are required for clinical applications. To improve the cancer diagnostic accuracy of label-free SERS spectral analysis of complex biological fluids, it is necessary to obtain specifically enhanced SERS signals of cancer-related metabolites present at low concentrations. RESULTS: This study presents a novel 3D SERS sensor, comprising a surface-carbonized silver nanowire (AgNW)-stacked filter membrane, alongside an optimized urine/methanol/chloroform extraction technique, which specifically changes the molecular adsorption and orientation of aromatic metabolites onto SERS substrates. By analyzing the pretreated urine samples on the surface-carbonized AgNW 3D SERS sensor, distinct and highly enhanced SERS peaks derived from semi-polar aromatic metabolites were observed for pancreatic cancer and prostate cancer samples compared with normal controls. Urine metabolite analysis using SERS fingerprinting successfully differentiated pancreatic cancer and prostate cancer groups from normal control group: normal control (n = 56), pancreatic cancer (n = 40), and prostate cancer (n = 39). SIGNIFICANCE AND NOVELTY: We confirmed the clinical feasibility of performing fingerprint analysis of urinary metabolites based on the surface-carbonized AgNW 3D SERS sensor and methanol/chloroform extraction for noninvasive cancer screening. This technology holds potential for large-scale screening owing to its high accuracy, and cost effective, simple and rapid detection method.


Subject(s)
Metal Nanoparticles , Nanowires , Pancreatic Neoplasms , Prostatic Neoplasms , Male , Humans , Spectrum Analysis, Raman/methods , Early Detection of Cancer , Silver/chemistry , Chloroform , Methanol , Metal Nanoparticles/chemistry
8.
China Journal of Endoscopy ; (12): 41-46, 2024.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1024827

ABSTRACT

Objective To compare the application value of filter membrane method and smear method on the evaluation of disinfection effect of flexible endoscope.Methods 242 flexible endoscopes after cleaning and disinfection from January 2022 to November 2022 were collected as the study subjects,and the disinfection effect of all endoscopes was tested by filter membrane method and smear method.The qualified rate,pathogen detection rate,colony detection and use cost of the two detection methods were compared.Results Among the 242 flexible endoscopes,the total qualified rate of filter membrane method was lower than that of smear method while the total detection rate of pathogenic bacteria and the number of bacterial colony were significantly higher than those of smear method(P<0.05).In the two evaluation methods,the colony count detected by gastroscopy was mainly≤100 cfu/n,and the colony count detected by enteroscopy was mainly≥100 cfu/n(P>0.05).The economic cost and time cost of filter membrane method were higher than those of smear method(P<0.05),and filter membrane method increased the annual depreciation cost of the suction filtration system of 976 yuan.Conclusion Compared with smear method,filter membrane method is more effective in evaluating the disinfection of flexible endoscope,but its economic cost and time cost are also higher.However,in order to build a green environment-friendly hospital,it is necessary to increase the investment of endoscopy center,thus it is recommended to apply filter membrane method.

9.
Mikrochim Acta ; 190(12): 469, 2023 Nov 16.
Article in English | MEDLINE | ID: mdl-37971627

ABSTRACT

A novel, simple, and rapid method is demonstrated for measuring the pore size and pore size distribution of filtration membranes (FMs) used in aqueous applications with fluorescence probes. Because the selected fluorescent probes are mixable and have strong signals, combined with the operation of dead-end filtration, this method only requires small amounts of reagents; additionally, it is time-efficient by avoiding multiple rounds of filtration. This method detects the size of a FM pore throat (i.e., the narrowest position of a pore tunnel), which is more consistent with the actual filtration situation. The conditions, such as probe concentration, temperature, transmembrane pressure difference, and types of surfactants, have been optimized. The experimental results show that the fluorescence probe method has good accuracy and reproducibility for measuring the pore size and pore size distribution of both organic and inorganic FMs. The method is particularly suitable for rapid testing of the filtration performance (nominal pore size≥0.02 µm) of purchased or synthetic membranes in the laboratory.

10.
Molecules ; 28(19)2023 Sep 22.
Article in English | MEDLINE | ID: mdl-37836593

ABSTRACT

The accumulation of proteins in filter membranes limits the efficiency of filtering technologies for cleaning wastewater. Efforts are ongoing to coat commercial filters with different materials (such as titanium dioxide, TiO2) to reduce the fouling of the membrane. Beyond monitoring the desired effect of the retention of biomolecules, it is necessary to understand what the biophysical changes are in water-soluble proteins caused by their interaction with the new coated filter membranes, an aspect that has received little attention so far. Using spin-label electron paramagnetic resonance (EPR), aided with native fluorescence spectroscopy and dynamic light scattering (DLS), here, we report the changes in the structure and dynamics of bovine serum albumin (BSA) exposed to TiO2 (P25) nanoparticles or passing through commercial polyvinylidene fluoride (PVDF) membranes coated with the same nanoparticles. We have found that the filtering process and prolonged exposure to TiO2 nanoparticles had significant effects on different regions of BSA, and denaturation of the protein was not observed, neither with the TiO2 nanoparticles nor when passing through the TiO2-coated filter membranes.


Subject(s)
Nanoparticles , Wastewater , Serum Albumin, Bovine/chemistry , Electron Spin Resonance Spectroscopy , Spin Labels , Titanium/chemistry , Nanoparticles/chemistry
11.
Environ Res ; 231(Pt 2): 116144, 2023 08 15.
Article in English | MEDLINE | ID: mdl-37201705

ABSTRACT

PM2.5 (particulate matter with a size of <2.5 µm) pollution has become a critical issue owing to its adverse health effects, including bronchitis, pneumonopathy, and cardiovascular diseases. Globally, around 8.9 million premature casualties related to exposure to PM2.5 were reported. Face masks are the only option that may restrict exposure to PM2.5. In this study, a PM2.5 dust filter was developed via the electrospinning technique using the poly (3-hydroxybutyrate) (PHB) biopolymer. Smooth and continuous fibers without beads were formed. The PHB membrane was further characterized, and the effects of the polymer solution concentration, applied voltage, and needle-to-collector distance were analyzed via the design of experiments technique, with three factors and three levels. The concentration of the polymer solution had the most significant effect on the fiber size and the porosity. The fiber diameter increased with increasing concentration, but decreases the porosity. The sample with a fiber diameter of ∼600 nm exhibited a higher PM2.5 filtration efficiency than the samples with a diameter of 900 nm, according to an ASTM F2299-based test. The PHB fiber mats fabricated at a concentration of 10%w/v, applied voltage of 15 kV, and needle tip-to-collector distance of 20 cm exhibited a high filtration efficiency of 95% and a pressure drop of <5 mmH2O/cm2. The tensile strength of the developed membranes ranged from 2.4 to 5.01 MPa, higher than those of the mask filters available in the market. Therefore, the prepared electrospun PHB fiber mats have great potential for the manufacture of PM2.5 filtration membranes.


Subject(s)
Dust , Filtration , 3-Hydroxybutyric Acid , Particulate Matter , Polymers
12.
Int J Biol Macromol ; 234: 123676, 2023 Apr 15.
Article in English | MEDLINE | ID: mdl-36796561

ABSTRACT

The goal of this study is to isolate cellulose nanocrystals (CNC) from sugarcane leaves (SCL) and fabricate filter membranes. Filter membranes consisting of the CNC and varying amount graphene oxide (GO) were fabricated using vacuum filtration technique. The α-cellulose content increased from 53.56 ± 0.49 % in untreated SCL to 78.44 ± 0.56 % and 84.99 ± 0.44 % in steam-exploded and bleached fibers, respectively. Atomic force microscopy (AFM) and transmission electron microscope (TEM) of CNC isolated from SCL indicated nanosized particles in the range of 7.3 nm and 150 nm for diameter and length, respectively. Morphologies of the fiber and CNC/GO membranes were determined by scanning electron microscopy (SEM) and crystallinity by X-ray diffraction (XRD) analysis of crystal lattice. The crystallinity index of CNC decreased with the addition of GO into the membranes. The CNC/GO-2 recorded the highest tensile index of 3.001 MPa. The removal efficiency increases with increasing GO content. The highest removal efficiency of 98.08 % was recorded for CNC/GO-2. CNC/GO-2 membrane reduced growth of Escherichia coli to 65 CFU compared to >300 CFU of control sample. SCL is a potential bioresource for isolation of cellulose nanocrystals and fabrication of high-efficiency filter membrane for particulate matter removal and inhibition of bacteria.


Subject(s)
Nanoparticles , Saccharum , Cellulose/chemistry , Particulate Matter , Nanoparticles/chemistry
13.
China Occupational Medicine ; (6): 441-446, 2023.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-1003882

ABSTRACT

Objective To establish a high performance liquid chromatography (HPLC) method for simultaneous determination of six aniline compounds (ADs) in workplace air. Methods GDH-1 air sampling tube was used to collect six co-existing ADs such as aniline, o-toluidine, N-methylaniline, m-methylaniline, p-methylaniline and N,N-dimethylaniline in the vapor and aerosol of workplace air. The samples were desorbed and eluted using a methanol solution containing 1.00% ammonia water, followed by separation on a C18 chromatographic column and detection using a diode array detector. Results The quantification range of the method was 0.19 -253.50 mg/L, with the correlation coefficient of 0.999 9 for all six ADs. The minimum detection range was 0.02-0.06 mg/m3, and the minimum quantitation range was 0.04-0.19 mg/m3 [both calculated for a 15.0 L sample with a desorption (elution) solution volume of 3.00 mL]. The average desorption and elution efficiencies were 92.15%-104.41% (silica gel) and 94.29%-104.29% (filter membrane). The intra-assay relative standard deviation (RSD) ranged from 0.90%-9.72% (silica gel) and 0.57%-6.96% (filter membrane). The inter-assay RSD ranged from 2.03%-9.78% (silica gel) and 2.50%-8.62% (filter membrane). The samples were stable at room temperature for seven days. Conclusion This method can be used for the simultaneous determination of six ADs in workplace air.

14.
Talanta ; 251: 123760, 2023 Jan 01.
Article in English | MEDLINE | ID: mdl-35964515

ABSTRACT

The development and application of portable and user-friendly biosensing technology for rapid detection of pathogenic bacteria are essential for human and environmental care. In this work, based on the phenomenon that the filter membrane can selectively separate MnO2 nanosheets (MnO2 NSs) and Mn2+, a novel label-free sensing platform was developed to detect the Escherichia coli (E. coli) using ß-galactosidase (ß-Gal) as a marker. MnO2 NSs were utilized as a dual-mode signal molecule of smartphone-based colorimetric analysis and inductively coupled plasma mass spectrometry (ICP-MS). ß-Gal can catalyze the 4-Aminophenyl ß-D-galactopyranoside (PAPG) to produce p-aminophenol (PAP), which could reduce MnO2 NSs to Mn2+. After selective separation of MnO2 NSs and Mn2+ by the filter, colorimetric detection was achieved with a smartphone by identifying the RGB value of the MnO2 NSs coated membrane, while the Mn2+ in the filtrate was detected by ICP-MS. Under optimal conditions, the limits of detection (LODs) of E. coli by smartphone-based RGB analysis and ICP-MS were 5.6 × 103 CFU mL-1 and 35 CFU mL-1, respectively. This method was successfully used for E. coli assay in meat, vegetables, and fruit samples with the advantages of sensitivity, simplicity, and short incubation time (within 1 h).


Subject(s)
Colorimetry , Escherichia coli , Colorimetry/methods , Galactose , Humans , Manganese Compounds , Oxides , Smartphone , beta-Galactosidase
15.
Cellulose (Lond) ; 29(11): 6205-6218, 2022.
Article in English | MEDLINE | ID: mdl-35693912

ABSTRACT

Abstract: Particulate matter (PM) pollution and SARS-CoV-2 (COVID-19) have brought severe threats to public health. High level of PM serves as a carrier of COVID-19 which is a global pandemic. This study fabricated filter membrane for face mask using bacterial cellulose and fingerroot extract (BC-FT) via immersion technique. The surface area, pore volume and pore size of BC were analyzed by Brunauer-Emmett-Teller. The physiochemical properties of the membrane were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffractometer. The crystallinity decreased from 63.7% in pure BC to 52.4% in BC-FT filter membrane. Young's modulus increased from 1277.02 MPa in pure BC to 2251.17 MPa in BC-FT filter membrane. The filter membrane showed excellent PM 0.1 removal efficiency of 99.83% and antimicrobial activity against Staphylococcus aureus and Escherichia coli. The fabricated membrane is excellent to prevent inhalation of PM2.5 and COVID-19 respiratory droplet. Supplementary information: The online version contains supplementary material available at 10.1007/s10570-022-04641-3.

16.
Spectrochim Acta A Mol Biomol Spectrosc ; 267(Pt 2): 120456, 2022 Feb 15.
Article in English | MEDLINE | ID: mdl-34653807

ABSTRACT

The consumption of food infected with food-borne pathogens has become a global public health problem. Therefore, it is monitor food-borne infections to avoid health and financial consequences. The rapid detection and differentiation of bacteria for biomedical and food safety applications continues to be a significant challenge. Herein, we present a label-free surface-enhanced Raman scattering approach for separating harmful bacteria from food. The method relies on the ascorbic acid reduction method to synthesize silver nanoparticles (AgNPs) and a polydimethylsiloxane (PDMS) multi-hole filter membrane chip (AgNPs@PDMS multi-hole filter membrane chip). Surface-enhanced Raman spectroscopy (SERS) was used, followed by multivariate statistical analysis to differentiate five important food-borne pathogens, including Staphylococcus aureus, Salmonella typhimurium, Listeria monocytogenes, Clostridium difficiles and Clostridium perfringens. The results demonstrated that compared to normal Raman signals, the intensity of the SERS signal was greatly enhanced with an analytical enhancement factor of 5.2 × 103. The spectral ranges of 400-1800 cm-1 were analyzed using principal component analysis (PCA) and stepwise linear discriminant analysis (SWLDA) were used to determine the optimal parameters for the discrimination of food-borne pathogens. The first three principal components (PC1, PC2, and PC3) accounted for 87.3% of the total variance in the spectra. The established SWLDA model had 100% accuracy and cross-validation accuracy, which accurately distinguished the SERS spectra of the five species. In conclusion, the SERS technology based on the AgNPs@PDMS multi-hole filter membrane chip was useful for the rapid identification of food-borne pathogens and can be employed for food quality management.


Subject(s)
Metal Nanoparticles , Spectrum Analysis, Raman , Dimethylpolysiloxanes , Discriminant Analysis , Silver
17.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-960431

ABSTRACT

Background Tin and its compounds can cause serious harm to human respiratory system and nervous system, but there is no corresponding national standard method for the determination of tin in PM2.5. Objective To establish a method for the determination of tin and its compounds in PM2.5 by atomic fluorescence spectrometry (AFS) after ultrasonic extraction with concentrated hydrochloric acid. Methods We extracted a fixed volume of air at a constant speed through a sampler with preset cutting characteristics to trap PM2.5 in the ambient air on quartz filter membranes. By selecting extraction solvent, comparing extraction temperature and time, and adjusting the acidity of solution to be measured, the sample pretreatment process was optimized, and a method for the determination of tin and its compounds in PM2.5 by AFS was proposed, and its performance indexes such as linearity, detection limit, and lower limit of quantification were obtained. The accuracy and precision of the method were evaluated by the standard addition recovery test with blank quartz filter membranes, and the interference test was carried out by adding standard urban particulate samples. The proposed method and the method recommended by the “Handbook on Monitoring and Protection of Air Pollution (Haze) Effects on Population Health (2020)” (the Handbook) were applied to actual samples, and the results were compared. Results This experiment used concentrated hydrochloric acid as the extraction solvent. The higher the reaction temperature and the longer the reaction time, the higher the recovery rate. Therefore, 70 ℃ water bath ultrasonic extraction for 3 h was selected. In terms of the proposed method, the linear range of detection was from 5.00 μg·L−1 to 50.00 μg·L−1, with a correlation coefficient ≥0.999 and a detection limit of 0.27 μg·L−1. When the quantitative detection of the lower limit was 0.90 μg·L−1,and the sampling volume was 144 m3, the limit of quantification was 1.25 ng·m−3. The recovery rate of standard addition of blank quartz filter membranes was 94.1%-97.5%, with a relative standard deviation ≤3.2%; the recovery rate of standard addition of standard urban particulate matter samples was 93.5%-103.0%, and the relative standard deviation was ≤2.1%, indicating that coexisting components in PM2.5 samples would not affect the determination of tin. For the 10 quartz filter membrane samples of PM2.5 monitoring, the results of tin by the established method (extraction with concentrated hydrochloric acid) were higher than those of the Handbook recommended method (extraction with nitric acid), and the difference is (3.61±0.54) ng·m−3(t=21.303, P<0.05). Conclusion The established method for the determination of tin and its compounds in PM2.5 by AFS after ultrasonic extraction with concentrated hydrochloric acid is simple, accurate, and suitable for laboratory determination of tin and its compounds in large quantities of PM2.5 samples.

18.
Polymers (Basel) ; 13(13)2021 Jun 22.
Article in English | MEDLINE | ID: mdl-34206523

ABSTRACT

The adsorption of proteins on membranes has been used for simple, low-cost, and minimal sample handling of large volume, low protein abundance liquid samples. Syringe-push membrane absorption (SPMA) is an innovative way to process bio-fluid samples by combining a medical syringe and protein-absorbable membrane, which makes SPMA a simple, rapid protein and proteomic analysis method. However, the membrane used for SPMA is only limited to commercially available protein-absorbable membrane options. To raise the method's efficiency, higher protein binding capacity with a lower back pressure membrane is needed. In this research, we fabricated electrospun polybutylene succinate (PBS) membrane and compared it to electrospun polyvinylidene fluoride (PVDF). Rolling electrospinning (RE) and non-rolling electrospinning (NRE) were employed to synthesize polymer fibers, resulting in the different characteristics of mechanical and morphological properties. Adding graphene oxide (GO) composite does not affect their mechanical properties; however, electrospun PBS membrane can be applied as a filter membrane and has a higher pore area than electrospun PVDF membrane. Albumin solution filtration was performed using all the electrospun filter membranes by the SPMA technique to measure the protein capture efficiency and staining of the protein on the membranes, and these membranes were compared to the commercial filter membranes-PVDF, nitrocellulose, and Whatman no. 1. A combination of rolling electrospinning with graphene oxide composite and PBS resulted in two times more captured protein when compared to commercial membrane filtration and more than sixfold protein binding than non-composite polymer. The protein staining results further confirmed the enhancement of the protein binding property, showing more intense stained color in compositing polymer with GO.

19.
J Colloid Interface Sci ; 603: 582-593, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34216954

ABSTRACT

The development of recyclable photocatalyst with high adsorption and excellent photocatalytic performance has attracted considerable attention. Herein, we report a three-component photocatalyst by constructing porous amine functionalized zirconium metal organic framework (UiO-66-NH2) and broad photo-responsive AgI on flexible carbon fiber cloth (CFC). UiO-66-NH2 nanoparticles (200-400 nm) were in-situ grown on the surface of CFC (16.5 ± 0.5 µm, 4 × 4 cm2) by a solvothermal route, then AgI particles (50-100 nm) were synthesized on CFC/UiO-66-NH2 via a modified chemical bath deposition method. The obtained CFC/UiO-66-NH2/AgI can effectively adsorb 19.0% levofloxacin (LVFX) or 18.4% ciprofloxacin (CIP) in 60 min in the dark and degrade 84.5% LVFX or 79.6% CIP in 120 min under visible light irradiation. Furthermore, the filter-membrane-shaped CFC/UiO-66-NH2/AgI can be utilized to treat the flowing sewage (CIP, 10 mg/L, ~1 L/h), and the removing efficiency of CIP reached 71.0% after 10 grades. Therefore, this work demonstrates the huge application prospect of recyclable CFC/UiO-66-NH2/AgI with high adsorption and photocatalytic capacity in flowing sewage treatment under visible light illumination.


Subject(s)
Metal-Organic Frameworks , Amines , Anti-Bacterial Agents , Carbon Fiber , Catalysis , Iodides , Silver Compounds , Zirconium
20.
J Hazard Mater ; 412: 125181, 2021 Jun 15.
Article in English | MEDLINE | ID: mdl-33951858

ABSTRACT

The selective detection and classification of NH3 and H2S gases with H2S gas interference based on conventional SnO2 thin film sensors is still the main problem. In this work, three layers of SnO2/Pt/WO3 nanofilms with different WO3 thicknesses (50, 80, 140, and 260 nm) were fabricated using the sputtering technique. The WO3 top layer were used as a gas filter to further improve the selectivity of sensors. The effect of WO3 thickness on the (NH3, H2, and H2S) gas-sensing properties of the sensors was investigated. At the optimal WO3 thickness of 140 nm, the gas responses of SnO2/Pt/WO3 sensors toward NH3 and H2 gases were slightly lower than those of Pt/SnO2 sensor film, and the gas response of SnO2/Pt/WO3 sensor films to H2S gas was almost negligible. The calcification of NH3 and H2 gases was effectively conducted by machine learning algorithms. These evidences manifested that SnO2/Pt/WO3 sensor films are suitable for the actual NH3 detection of NH3 and H2S gases.

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