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Synthesis, characterization and bactericidal assessment of MgO polymeric fiber nanocomposites for water disinfection
Vega Avila, Ana Lucia
Vega Avila, Ana Lucia
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Abstract
Este trabajo describe la sÃntesis, caracterización y evaluación de las propiedades
bactericidas de las nanopartÃculas de óxido de magnesio (MgO NP). Las propiedades
bactericidas del MgO NP se evaluaron contra tres cepas de bacterias diferentes teniendo en
cuenta los efectos de la concentración, el tiempo de tratamiento y el tipo de precursor.
Las nanopartÃculas de óxido de magnesio se sintetizaron a partir de hidróxido de magnesio
y de hidromagnesita. La formación del MgO NP y sus precursores fue confirmada por
difracción de rayos X y espectroscopÃa de rayos X de energÃa dispersiva. El análisis de
espectroscopÃa infrarroja por transformada de Fourier evidenció quimisorción de CO2 y
H2O en la superficie del MgO NP, mientras que la generación de especies reactivas de
oxÃgeno (ROS) se confirmó mediante la degradación de azul de metileno en presencia del
MgO NP.
Las nanopartÃculas de óxido de magnesio exhibieron un efecto bactericida contra
Salmonella entérica ATCC 14020, E. coli ATCC 25922 y Estafilococos aureus ATCC
25923. Este efecto bactericida fue dependiente de la concentración del MgO NP y del
tiempo de tratamiento, pero independiente del tipo de precursor. Adicionalmente, el efecto
bactericida del MgO NP se asoció con el incremento en el pH observado en los medios de
cultivo durante el tratamiento.
Por otro lado, el MgO NP se inmovilizó en membranas electrohiladas de
poliacrilonitrilo (PAN) para proporcionarles control de permeabilidad y propiedades
bactericidas. Las pruebas bactericidas realizadas a las membranas electrohiladas
confirmaron que las membranas de PAN-20% MgO inhibieron completamente el
crecimiento de E. coli a una dosis de 0.100 g de membrana / 10 ml del medio tratado
después de 24 horas. Las membranas electrohiladas también fueron efectivas para eliminar
E. coli y S. thyphimurium de medios acuosos por filtración; se requirieron dos capas
superpuestas de membranas de PAN y cuatro capas de PAN-10% MgO para eliminar los
microorganismos del medio acuoso. Finalmente, las membranas electrohiladas se usaron para desinfectar muestras de
aguas residuales de la Autoridad de Acueductos y Alcantarillados de Puerto Rico en Lajas.
Se encontró que las membranas de PAN-10% MgO dosificadas en una concentración de
0.150g / 10 mL de agua inhibieron completamente el crecimiento de las bacterias Gramnegativas
y de Estreptococos después de dos horas de tratamiento.
Los resultados obtenidos apuntan a la generación de ROS asistida por el efecto
alcalino como el mecanismo responsable del efecto antimicrobiano mostrado por el MgO
NP. Además, se confirmó la viabilidad de emplear membranas electrohiladas de PANMgO
como compuesto antimicrobiano para posibles aplicaciones de purificación de agua.
The synthesis, characterization, and assessment of the bactericidal properties of magnesium oxide nanoparticles ( MgO NP) are described in this work. The effects of MgO NP concentration, treatment time, and precursor type on MgO NP bactericidal behavior were evaluated against three different bacteria strains. MgO NP were synthesized from Magnesium hydroxide and hydromagnesite. The formation of MgO NP and its precursors was confirmed by X-Ray Diffraction and Energy Dispersive X-Ray Spectroscopy. Fourier Transform Infrared Spectroscopy analysis evidenced CO2 and H2O chemisorption onto MgO NP surface, and the generation of reactive oxygen species (ROS) was confirmed by methylene blue degradation in the presence of MgO NP. MgO NP exhibited a complete bactericidal effect against Salmonella typhimurium ATCC 14020, E. coli ATCC 25922, and Staphylococcus aureus ATCC 25923. This bactericidal effect was dependent on MgO NP concentration and treatment time but not on the precursor type. Additionally, the bactericidal effect of MgO NP was associated with the increment in the pH of the culture media observed during treatment. Additionally, MgO NP were immobilized into Polyacrylonitrile (PAN) electrospun nanofibers to provide them with permeability control, fouling resistance, and antibacterial properties. Antibacterial tests conducted to electrospun membranes confirm that PAN-20% MgO completely inhibited E. coli growth at a dose of 0.100 g membrane/10 mL of the treated medium after 24 hours. Electrospun membranes were also effective in removing E. coli and S. thyphimurium from aqueous media by membrane filtration. Stacks of two layers of PAN and four layers of PAN-10% MgO were sufficient to eliminate the microorganisms. Finally, electrospun membranes were used to disinfect wastewater samples from the Puerto Rico Aqueduct and Sewer Authority at Lajas. It was found that PAN- 10% MgO dosed in a concentration of 0.1500g/10 mL of water completely inhibited the growth of the Gramnegative bacteria and Streptococcus after two hours of treatment. The results hint at ROS generation assisted by the alkaline effect as the mechanism responsible for the antimicrobial effect displayed by MgO NP. Furthermore, the viability of employing PAN-MgO electrospun composite membranes as an antimicrobial compound for potential water purification applications was also confirmed.
The synthesis, characterization, and assessment of the bactericidal properties of magnesium oxide nanoparticles ( MgO NP) are described in this work. The effects of MgO NP concentration, treatment time, and precursor type on MgO NP bactericidal behavior were evaluated against three different bacteria strains. MgO NP were synthesized from Magnesium hydroxide and hydromagnesite. The formation of MgO NP and its precursors was confirmed by X-Ray Diffraction and Energy Dispersive X-Ray Spectroscopy. Fourier Transform Infrared Spectroscopy analysis evidenced CO2 and H2O chemisorption onto MgO NP surface, and the generation of reactive oxygen species (ROS) was confirmed by methylene blue degradation in the presence of MgO NP. MgO NP exhibited a complete bactericidal effect against Salmonella typhimurium ATCC 14020, E. coli ATCC 25922, and Staphylococcus aureus ATCC 25923. This bactericidal effect was dependent on MgO NP concentration and treatment time but not on the precursor type. Additionally, the bactericidal effect of MgO NP was associated with the increment in the pH of the culture media observed during treatment. Additionally, MgO NP were immobilized into Polyacrylonitrile (PAN) electrospun nanofibers to provide them with permeability control, fouling resistance, and antibacterial properties. Antibacterial tests conducted to electrospun membranes confirm that PAN-20% MgO completely inhibited E. coli growth at a dose of 0.100 g membrane/10 mL of the treated medium after 24 hours. Electrospun membranes were also effective in removing E. coli and S. thyphimurium from aqueous media by membrane filtration. Stacks of two layers of PAN and four layers of PAN-10% MgO were sufficient to eliminate the microorganisms. Finally, electrospun membranes were used to disinfect wastewater samples from the Puerto Rico Aqueduct and Sewer Authority at Lajas. It was found that PAN- 10% MgO dosed in a concentration of 0.1500g/10 mL of water completely inhibited the growth of the Gramnegative bacteria and Streptococcus after two hours of treatment. The results hint at ROS generation assisted by the alkaline effect as the mechanism responsible for the antimicrobial effect displayed by MgO NP. Furthermore, the viability of employing PAN-MgO electrospun composite membranes as an antimicrobial compound for potential water purification applications was also confirmed.
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Date
2022-12-12
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Keywords
Electrospinning, water disinfection, MgO nanoparticles, Composite nanofibers, Antibacterial properties