scholarly journals Preparation of Ag/HBP/PAN Nanofiber Web and Its Antimicrobial and Filtration Property

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Li-Rong Yao ◽  
Xiao-Mo Song ◽  
Guang-Yu Zhang ◽  
Shan-Qing Xu ◽  
Ye-Qun Jiang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ag Nanoparticles ◽  
High Porosity ◽  
Filtration Property ◽  
Bacterial Reduction ◽  
Cooperative Effects ◽  
E Coli ◽  
Nanofiber Web ◽  
Dispersion Solution ◽  
Pan Nanofiber

To widen the application of nanofibers web in the field of medical health materials, a new Ag/amino-terminated hyperbranched polymer (HBP)/polyacrylonitrile (PAN) nanofiber web with excellent antimicrobial activity and filtration property was produced with Ag/HBP dispersion solution and PAN nanofiber. Ag/HBP dispersion solution was prepared with HBP as reducer and stabilizer, and Ag/HBP/PAN nanofiber was prepared by modifying electrospun PAN nanofiber with Ag/HBP aqueous solution. The characterization results showed that spherical Ag nanoparticles were prepared and they had a narrow distribution in HBP aqueous solution. The results of Ag/HBP/PAN nanofiber characterized with SEM and EDS showed that the content of silver nanoparticles on the surface of PAN nanofiber was on the increase when the treating temperature rose. The bacterial reduction rates of HBP-treated PAN nanofiber againstS. aureusandE. coliwere about 89%, while those of the Ag/HBP/PAN nanofiber againstS. aureusandE. coliwere 99.9% and 99.96%, respectively, due to the cooperative effects from the amino groups in HBP and Ag nanoparticles. Moreover, the small pores and high porosity in Ag/HBP/PAN nanofiber web resulted in high filtration efficiency (99.9%) for removing smaller particles (0.1 μm~0.7 μm), which was much higher than that of the gauze mask.

scholarly journals ᶫ-Leucine Loading and Release in MIL-100 Nanoparticles

2020 ◽  
Vol 21 (24) ◽  
pp. 9758
Author(s):  
Ivan E. Gorban ◽  
Mikhail A. Soldatov ◽  
Vera V. Butova ◽  
Pavel V. Medvedev ◽  
Olga A. Burachevskaya ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrothermal Synthesis ◽  
Cell Model ◽  
Metal Organic Framework ◽  
Acetic Acid Solution ◽  
Sorption Isotherms ◽  
Microwave Assisted Synthesis ◽  
High Porosity ◽  
Cytotoxicity Studies ◽  
Vis Spectroscopy

Synthesis of the MIL-100 metal-organic framework particles was carried out by hydrothermal (HT) and microwave (MW)-assisted methods. Transmission electron microscopy showed formation of microparticles in the course of hydrothermal synthesis and nanoparticles for microwave-assisted synthesis. Powder X-ray diffraction confirmed formation of larger crystallites for hydrothermal synthesis. Particle aggregation in aqueous solution was observed by dynamic light scattering. However, the stability of both samples could be improved in acetic acid solution. Nitrogen sorption isotherms showed high porosity of the particles. ᶫ-leucine molecule was used as a model molecule for loading in the porous micro- and nanoparticles. Loading was estimated by FTIR spectroscopy and thermogravimetric analysis. UV-VIS spectroscopy quantified ᶫ-leucine release from the particles in aqueous solution. Cytotoxicity studies using the HeLa cell model showed that the original particles were somewhat toxic, but ᶫ-leucine loading ameliorated the toxic effects, likely due to signaling properties of the amino acid.

scholarly journals Photodegradation of fluoroquinolones in aqueous solution under light conditions relevant to surface waters, toxicity assessment of photoproduct mixtures.

2021 ◽  
Author(s):  
Sarka Klementova ◽  
Martina Poncarová ◽  
Helena Langhansová ◽  
Jaroslava Lieskovská ◽  
David Kahoun ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Antibacterial Activity ◽  
Surface Waters ◽  
Ph Value ◽  
Reaction System ◽  
Photochemical Degradation ◽  
Alkaline Ph ◽  
Light Conditions ◽  
E Coli ◽  
Neutral Ph

Abstract Photochemical degradation of fluoroquinolones ciprofloxacin, enrofloxacin and norfloxacin in aqueous solution under light conditions relevant to surface waters at neutral and alkaline pH was found to proceed readily with half-lives between 0.9 and 2.7 min. The products of photochemical degradation identified by HPLC-MS included defluorinated, hydroxylated, and decarboxylated structures as well as structures with opened cyclic structures. For all of the studied substances, the reaction pathways were influenced significantly by the pH of the reaction system, with more products formed at alkaline pH than at neutral pH: the ratios of products in neutral and alkaline pH were 16/26, 9/19, 15/23 for ciprofloxacin, enrofloxacin, and norfloxacin, respectively. The structures of photoproducts and pathways of photochemical degradation are proposed. The antibacterial activities of photoproduct mixtures tested on E. coli and S. epidermidis were significantly higher in comparison to parental antibiotics in the case of both ciprofloxacin and enrofloxacin with p-values less than 0.0001 in most cases. The effect of the photoproducts was shown to be dependent on the pH value of the original antibiotic solutions before photodegradation: for ciprofloxacin, antibacterial activity against E. coli was more notably pronounced with regard to neutral pH photoproducts, while a less significant, or in one case not significant, effect of pH was observed against S. epidermidis ; for norfloxacin, antibacterial activity against both E. coli and S. epidermidis were especially high with regard to alkaline pH photoproducts

Removal of reactive dyes from aqueous solution by different bacterial genera

1996 ◽  
Vol 34 (10) ◽  
pp. 89-95 ◽  
Author(s):  
Hu Tai-Lee
Keyword(s):  
Aqueous Solution ◽  
Reactive Dyes ◽  
Bacterial Biomass ◽  
Gram Negative Bacteria ◽  
Adsorption Parameters ◽  
Gram Negative ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Mixed Biomass ◽  
Decreasing Ph

The use of biomass for the removal of reactive dyes from an aqueous solution with different bacterial genera has been investigated. Three Gram-negative bacteria: Aeromonas sp., P. luteola and E. coli, and two Gram-positive bacteria: B. subtilis and S. aureus and a mixed biomass of activated sludge are the tested biosorbents. Dead cells of Gram-negative bacteria have a higher specific adsorption capacity than the living cells. The dye removal is in the order of Aeromonoas sp. > P. luteola > E. coli. The adsorption equilibrium can be reached within one hour. Due to the positively charged cells at acidic pH, the removal of reactive dyes increases with decreasing pH. Evaluating the adsorption parameters, bacterial biomass exhibits stable adsorption characteristics, which makes it a suitable adsorbent for different dye compounds.

scholarly journals Emergence of Macrolide Resistance Gene mph(B) in Streptococcus uberis and Cooperative Effects with rdmC-Like Gene

2008 ◽  
Vol 52 (8) ◽  
pp. 2767-2770 ◽  
Author(s):  
Adeline Achard ◽  
Véronique Guérin-Faublée ◽  
Vianney Pichereau ◽  
Corinne Villers ◽  
Roland Leclercq
Keyword(s):  
Resistance Mechanism ◽  
Hindiii Fragment ◽  
Cooperative Effects ◽  
E Coli ◽  
Streptococcus Uberis ◽  
Macrolide Resistance Gene ◽  
Alpha Beta ◽  
Low Levels ◽  
Plasmid Puc18 ◽  
Hydrolase Family

ABSTRACT Streptococcus uberis UCN60 was resistant to spiramycin (MIC = 8 μg/ml) but susceptible to erythromycin (MIC = 0.06 μg/ml), azithromycin (MIC = 0.12 μg/ml), josamycin (MIC = 0.25 μg/ml), and tylosin (MIC = 0.5 μg/ml). A 2.5-kb HindIII fragment was cloned from S. uberis UCN60 DNA on plasmid pUC18 and introduced into Escherichia coli AG100A, where it conferred resistance to spiramycin by inactivation. The sequence analysis of the fragment showed the presence of an rdmC-like gene that putatively encoded a protein belonging to the alpha/beta hydrolase family and of the first 196 nucleotides of the mph(B) gene putatively encoding a phosphotransferase known to inactivate 14-, 15-, and 16-membered macrolides in E. coli. The entire mph(B) gene was then identified in S. uberis UCN60. The two genes were expressed alone or in combination in E. coli, Staphylococcus aureus, and Enterococcus faecalis. Analysis of MICs revealed that rdmC-like alone did not confer resistance to erythromycin, tylosin, and josamycin in those three hosts. It conferred resistance to spiramycin in E. coli and E. faecalis but not in S. aureus. mph(B) conferred resistance in E. coli to erythromycin, tylosin, josamycin, and spiramycin but only low levels of resistance in E. faecalis and S. aureus to spiramycin (MIC = 8 μg/ml). The combination of mph(B) and rdmC-like genes resulted in a resistance to spiramycin and tylosin in the three hosts that significantly exceeded the mere addition of the resistance levels conferred by each resistance mechanism alone.

scholarly journals Highly Porous and Nutrients-Rich Biochar Derived from Dairy Cattle Manure and Its Potential for Removal of Cationic Compound from Water

Agriculture ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 114 ◽  
Author(s):  
Wen-Tien Tsai ◽  
Chien-Hung Hsu ◽  
Yu-Quan Lin
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Low Cost ◽  
Total Pore Volume ◽  
Dairy Manure ◽  
Bet Surface Area ◽  
High Porosity ◽  
Crop Fields ◽  
Effective Removal ◽  
Highly Porous

The use of biochar in the horticulture and crop fields is a recent method to improve soil fertility due to its porous features and rich nutrients. In the present study, dairy manure (DM) was used as a biomass precursor in the preparation of highly porous biochar (DM-BC) produced at specific conditions. Based on N2 adsorption-desorption isotherms and scanning electron microscopy (SEM) observations, the resulting biochar featured its microporous/mesoporous textures with a BET surface area of about 300 m2/g and total pore volume of 0.185 cm3/g, which could be a low-cost biosorbent for the effective removal of methylene blue (MB) from the aqueous solution. As observed by the energy dispersive X-ray spectroscopy (EDS), the primary inorganic nutrients on the surface of DM-BC included calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), silicon (Si), sulfur (S), sodium (Na) and aluminum (Al). Furthermore, the resulting biochar was investigated in duplicate for its biosorption performance of cationic compound (i.e., methylene blue, MB) from the aqueous solution with various initial MB concentrations and DM-BC dosages at 25 °C. The findings showed that the biosorption kinetic parameters fitted by the pseudo-second order rate model with high correlations were consistent with its porous features. These experimental results suggested that the porous DM-based biochar could be reused as a biosorbent, biofertilizer, or soil amendments due to the high porosity and the abundance in nutrient minerals.

Supported silver catalysts prepared by deposition in aqueous solution of Ag nanoparticles obtained through a photochemical approach

2009 ◽  
Vol 367 (1-2) ◽  
pp. 138-145 ◽  
Author(s):  
S. Scirè ◽  
C. Crisafulli ◽  
S. Giuffrida ◽  
C. Mazza ◽  
P.M. Riccobene ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ag Nanoparticles ◽  
Silver Catalysts

Photocatalytic removal of nitrate using TiO2/polyacrylonitrile nanofiber membrane synthesized by co-electrospinning process

2014 ◽  
Vol 14 (4) ◽  
pp. 554-560 ◽  
Author(s):  
S. P. Suriyaraj ◽  
M. Benasir Begam ◽  
S. G. Deepika ◽  
P. Biji ◽  
R. Selvakumar
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Tio2 Nanoparticles ◽  
Nitrate Removal ◽  
Electrospinning Process ◽  
Order Kinetic ◽  
Nanofiber Membrane ◽  
Electrospinning Technique ◽  
X Ray ◽  
Pan Nanofiber

The present study investigates the development of titanium dioxide (TiO2)/polyacrylonitrile (PAN) nanofiber membrane for the removal of nitrate from aqueous solution by photocatalysis. The TiO2 nanoparticles were synthesized by conventional sol–gel method followed by blending them into PAN polymer. The blended solution was electrospun into nanofiber using the co-electrospinning technique. The nanoparticle, PAN nanofibers and the TiO2 impregnated nanofibers were characterized using suitable techniques like X-ray diffraction, high-resolution transmission electron microscopy and scanning electron microscopy attached with energy dispersive X-ray spectroscopy. The average size and the diameter of the TiO2 nanoparticles and TiO2/PAN nanofibers were found to be 22 ± 0.32 nm and 90 ± 15 nm respectively. TiO2 nanoparticles and TiO2/PAN nanofibers showed maximum nitrate removal of 74.67 and 39% respectively at 10 mg/L nitrate concentration at pH 4. However at higher concentration (50 mg/L), the nitrate removal was found to be only 16.87%. The experimental data were fitted onto pseudo second-order kinetic model. The impregnation of TiO2 nanoparticles into the PAN nanofibers by co-electrospinning techniques lead to higher removal of nitrate in aqueous solution at lower concentration (10 mg/L and below). However at higher concentration, the TiO2/PAN nanofiber membrane was inefficient to remove nitrate.

scholarly journals Antibacterial and UV protective properties of polyamide fabric impregnated with TiO2/Ag nanoparticles

2015 ◽  
Vol 80 (5) ◽  
pp. 705-715 ◽  
Author(s):  
Milica Milosevic ◽  
Ana Krkobabic ◽  
Marija Radoicic ◽  
Zoran Saponjic ◽  
Vesna Lazic ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Ag Nanoparticles ◽  
Uv Protection ◽  
Bacterial Reduction ◽  
Protective Properties ◽  
Polyamide Fabric ◽  
Uv Protective Properties

The possibility of in situ photoreduction of Ag+ ions using colloidal TiO2 nanoparticles deposited on the surface of polyamide fabric in the presence of amino acid alanine and methyl alcohol is discussed. The presence of TiO2/Ag nanoparticles on the polyamide fabric was confirmed by FESEM and ICP analyses. Antibacterial activity of the fabric was tested against Gram-negative bacterium Escherichia coli and Gram-positive bacterium Staphylococcus aureus. Fabricated TiO2/Ag nanoparticles on the surface of polyamide fabric provided maximum bacterial reduction and thus, excellent antibacterial activity. In spite of silver leaching from the fabric during washing, impregnated polyamide fabric preserved maximum reduction of Escherichia coli colonies. Antibacterial activity against Staphylococcus aureus slightly decreased after ten washing cycles, but still antibacterial activity can be considered as satisfactory. In addition, the presence of TiO2/Ag nanoparticles ensured better UV protection efficiency which belongs to very good UV protection category.

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