scholarly journals Photocatalytic Bactericidal Performance of LaFeO3 under Solar Light: Kinetics, Spectroscopic and Mechanistic Evaluation

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1135
Author(s):  
Nazmiye Cemre Birben ◽  
Ezgi Lale ◽  
Renato Pelosato ◽  
Ceyda Senem Uyguner Demirel ◽  
Isabella Natali Sora ◽  
...  
Keyword(s):  
Reaction Medium ◽  
Solar Irradiation ◽  
Spectroscopic Techniques ◽  
Ultrapure Water ◽  
Contributing Factors ◽  
Experimental Conditions ◽  
E Coli ◽  
Almost All ◽  
Simulated Solar Irradiation

Lanthanum orthoferrites are a versatile class of catalysts. Here, the photocatalytic bactericidal performance of LaFeO3 (LF) to inactivate pathogenic microorganisms, i.e., Escherichia coli (E. coli), in water under simulated solar irradiation conditions was investigated. Various competing and contributing factors were covered to visualize the reaction medium consisting of E. coli K12 cells, organic sub-fractions formed by cell destruction, and LF surface. LF solar photocatalytic inactivation (SPCI) kinetics revealed the highest inactivation rate in ultrapure water as expected, followed by distilled water (DW), aqueous solution containing anions and cations (WM) and saline solution (SS). Characterization of the released organic matter was achieved by UV-vis and fluorescence spectroscopic techniques as well as organic carbon contents (DOC). Upon SPCI, significant amounts of K+ along with released protein contents were detected expressing cell wall destruction and lysis. Under the specified experimental conditions, in the presence of released intracellular organic and inorganic components via cell lysis, a significant count of E. coli was still present in SS, whereas almost all bacteria were removed in other matrices due to various challenging reasons. Based on the presented data, SPCI of E. coli using LF as a novel photocatalyst was successfully demonstrated as an alternative and promising method for disinfection purposes.

The critical role of light in moderating microbial stress due to mixtures of engineered nanomaterials

2018 ◽  
Vol 5 (1) ◽  
pp. 96-102 ◽  
Author(s):  
Carolyn M. Wilke ◽  
Jean-François Gaillard ◽  
Kimberly A. Gray
Keyword(s):  
Critical Role ◽  
Engineered Nanomaterials ◽  
Metal Nanoparticle ◽  
Toxic Effects ◽  
Solar Irradiation ◽  
Localized Surface Plasmon ◽  
E Coli ◽  
Simulated Solar Irradiation ◽  
Role Of Light

Light influences chemical interactions of engineered nanomaterials and their toxic effects. Under simulated solar irradiation, we observed that binary mixtures of n-Ag, n-Au, or n-Pt with n-TiO2cause synergistic toxic effects inE. colidue to photochemical interactions governed by metal nanoparticle stability and localized surface plasmon resonance.

scholarly journals GREEN SYNTHESIS AND SPECTROSCOPIC CHARACTERIZATION OF IRON (III) COMPLEX OF UREA FROM HUMAN URINE AND IRON RUST

2020 ◽  
Vol 45 (5) ◽  
Author(s):  
V.O. Uduah ◽  
J.J. Gongden ◽  
M.L. Kagoro ◽  
K.K. Gurumyen ◽  
Y.N. Lohdip ◽  
...  
Keyword(s):  
Human Urine ◽  
Synthesis Method ◽  
Reaction Medium ◽  
Spectroscopic Characterization ◽  
Waste Materials ◽  
Spectroscopic Techniques ◽  
Distilled Water ◽  
Oxide Composition ◽  
Ft Ir

This work presents a dry synthesis of Iron (III) complex with urea isolated from human urine and Fe (III) obtained from iron rust particles. Iron (III), PI (Purified iron rust), was isolated from iron rust in 10% hydrochloric acid, HCl and distilled water respectively. The complex was synthesized via dry-synthesis method using the melted urea as reaction medium. The isolated Fe (III) was characterized by elemental analysis which was done using XRF Cu-Zn method. The complex was prepared in a 1:4 metal to ligand (M-L) ratio. The stoichiometry of reaction indicate a 1:3 ratio of M-L (Fe-U). The complex was characterized by FT-IR, UV-vis, XRF and XRD spectroscopic techniques. The Fe (III) isolate and Fe-U complex shows percentage yields of 35.7% and ~92% respectively. The elemental and oxide composition of Fe and Fe2O3 (i.e., PI) were 40.387% and 57.753% respectively. The results obtained from the characterization of the iron-urea complex, IUC, indicate FT-IR result as symmetric and asymmetric frequencies with peaks of a combination band of Vs (NH) and Vas (NH), C=O and V (C-N) all stretched, XRD showed the crystal to be amorphous. The elemental and oxide composition of the Fe and Fe2O3 in IUC were 40.007 and 44.201 respectively. The results obtained revealed that useful complexes can be synthesized easily from waste materials, such as urine and iron rust particles, which complement Green chemistry.

scholarly journals Synergistic effect of heat and solar UV on DNA damage and water disinfection of E. coli and bacteriophage MS2

2012 ◽  
Vol 10 (4) ◽  
pp. 605-618 ◽  
Author(s):  
Dana Jennifer Theitler ◽  
Abid Nasser ◽  
Yoram Gerchman ◽  
Abraham Kribus ◽  
Hadas Mamane
Keyword(s):  
Dna Damage ◽  
Synergistic Effect ◽  
Water Disinfection ◽  
Solar Irradiation ◽  
Solar Simulator ◽  
E Coli ◽  
Bacteriophage Ms2 ◽  
Sensitive Site ◽  
Solar Uv ◽  
Simulated Solar Irradiation

The response of a representative virus and indicator bacteria to heating, solar irradiation, or their combination, was investigated in a controlled solar simulator and under real sun conditions. Heating showed higher inactivation of Escherichia coli compared to the bacteriophage MS2. Heating combined with natural or simulated solar irradiation demonstrated a synergistic effect on the inactivation of E. coli, with up to 3-log difference for 50 °C and natural sun insolation of 2,000 kJ m−2 (compared to the sum of the separate treatments). Similar synergistic effect was also evident when solar-UV induced DNA damage to E. coli was assessed using the endonuclease sensitive site assay (ESS). MS2 was found to be highly resistant to irradiation and heat, with a slightly synergistic effect observed only at 59 °C and natural sun insolation of 5,580 kJ m−2. Heat treatment also hindered light-dependent recovery of E. coli making the treatment much more effective.

Colicinogeny among Escherichia coli Serotypes, Including O157:H7, Representing Four Closely Related Diarrheagenic Clones

1998 ◽  
Vol 61 (11) ◽  
pp. 1431-1438 ◽  
Author(s):  
SHELTON E. MURINDA ◽  
SHU-MIN LIU ◽  
ROBERT F. ROBERTS ◽  
RICHARD A. WILSON
Keyword(s):  
Escherichia Coli ◽  
Toxin Production ◽  
Coli Strain ◽  
The Other ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Reference Set ◽  
Almost All ◽  
Luria Agar

Twenty-seven diarrheagenic Escherichia coli (DEC) strains from five closely related, genetically distinct clones (DEC 3, 4, 8, 9, and 10), representing serotypes commonly associated with Shiga-like toxin production, i.e., 015:H−, 026:(H11, H−), 0111:(H8, H11, H−), and O157:H7, were evaluated for colicinogeny on Luria agar or Luria agar containing 0.25 μg/ml mitomycin C to induce colicin production. Ten (37%) of the DEC strains tested were colicinogenic. One of 11 serotype O157:H7 strains, DEC strain 4E, produced a colicin identified as Col D. DEC strains 8B, 9D, and 10B produced Col E1, whereas DEC strain 10A produced Col E2. DEC strains 8A, 8E, 10C, 10E, and 10F produced “untypable” colicins that killed almost all Pugsley Colicin Reference Set strains and the other DEC strains tested. To aid with further characterization of the colicins, plasmids extracted from each colicin-producing (Col+) DEC strain were used to transform E. coli strain DH5α. All Col+ DH5α transformants contained one plasmid ranging in size from 1.3 to 10 kb. Some transformants were stable colicin producers whereas others were unstable. The inhibitory activity and colicin sensitivity and insensitivity profiles of the Col+ transformants were similar to those of the corresponding Col+ donor DEC strains. It appears that the untypable colicins are novel and, thus, warrant further study. Colicin production by some of the DEC strains evaluated partly explains why they were insensitive to standard colicins in a previous study.

scholarly journals Resistance and induction of viable but non culturable states (VBNC) during inactivation of E. coli and Klebsiella pneumoniae by addition of H2O2 to natural well water under simulated solar irradiation

2021 ◽  
Vol 188 ◽  
pp. 116499 ◽  
Author(s):  
John J. Alvear-Daza ◽  
Alejandra García-Barco ◽  
Paula Osorio-Vargas ◽  
Héctor M. Gutiérrez-Zapata ◽  
Janeth Sanabria ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Solar Irradiation ◽  
Well Water ◽  
E Coli ◽  
Simulated Solar Irradiation

scholarly journals Molecular Characterization of OXA-48-Like-Producing Enterobacteriaceae in the Czech Republic and Evidence for Horizontal Transfer of pOXA-48-Like Plasmids

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Anna Skalova ◽  
Katerina Chudejova ◽  
Veronika Rotova ◽  
Matej Medvecky ◽  
Vendula Studentova ◽  
...  
Keyword(s):  
Czech Republic ◽  
Horizontal Transfer ◽  
Sequencing Data ◽  
S1 Nuclease ◽  
The Czech Republic ◽  
Content Type ◽  
E Coli ◽  
Almost All ◽  
Sequence Types

ABSTRACT The aim of this study was to characterize the first cases and outbreaks of OXA-48-like-producing Enterobacteriaceae recovered from hospital settings in the Czech Republic. From 2013 to 2015, 22 Klebsiella pneumoniae isolates, 3 Escherichia coli isolates, and 1 Enterobacter cloacae isolate producing OXA-48-like carbapenemases were isolated from 20 patients. Four of the patients were colonized or infected by two or three different OXA-48-like producers. The K. pneumoniae isolates were classified into nine sequence types (STs), with ST101 being predominant (n = 8). The E. coli isolates were of different STs, while the E. cloacae isolate belonged to ST109. Twenty-four isolates carried bla OXA-48, while two isolates carried bla OXA-181 or bla OXA-232. Almost all isolates (n = 22) carried bla OXA-48-positive plasmids of a similar size (∼60 kb), except the two isolates producing OXA-181 or OXA-232. In an ST45 K. pneumoniae isolate and an ST38 E. coli isolate, S1 nuclease profiling plus hybridization indicated a chromosomal location of bla OXA-48. Sequencing showed that the majority of bla OXA-48-carrying plasmids exhibited high degrees of identity with the pOXA-48-like plasmid pE71T. Additionally, two novel pE71T derivatives, pOXA-48_30715 and pOXA-48_30891, were observed. The bla OXA-181-carrying plasmid was identical to the IncX3 plasmid pOXA181_EC14828, while the bla OXA-232-carrying plasmid was a ColE2-type plasmid, being a novel derivative of pOXA-232. Finally, sequencing data showed that the ST45 K. pneumoniae and ST38 E. coli isolates harbored the IS1R-based composite transposon Tn6237 containing bla OXA-48 integrated into their chromosomes. These findings underlined that the horizontal transfer of pOXA-48-like plasmids has played a major role in the dissemination of bla OXA-48 in the Czech Republic. In combination with the difficulties with their detection, OXA-48 producers constitute an important public threat.

scholarly journals Synthesis and Characterization of Piperidin-4-one Derivatives Using Green Solvent

2020 ◽  
Vol 32 (4) ◽  
pp. 981-984 ◽  
Author(s):  
K. Hemalatha ◽  
D. Ilangeswaran
Keyword(s):  
Deep Eutectic Solvent ◽  
Reaction Medium ◽  
Synthesis And Characterization ◽  
Synthetic Method ◽  
Spectroscopic Techniques ◽  
Green Solvent ◽  
Environmentally Safe ◽  
Ft Ir ◽  
Effective Reaction

A deep eutectic solvent of glucose-urea was found to be an inexpensive and effective reaction medium in the synthesis of piperidin-4-one derivatives. In this work, 3-methyl-2,6-diphenyl piperidin-4-one (4a), 3,5-dimethyl-2,6-diphenylpiperidin-4-one (4b), 2,6-diphenylpiperidin-4-one (4c), piperidin-4- one (4d), 3,5-dimethylpiperidin-4-one (4e), 3-methyl-2,6-di(2-hydroxyphenyl)piperidin-4-one (4f), 3,5-dimethyl 2,6-di(2-hydroxyphenyl)piperidin-4one (4g) were synthesized using a deep eutectic solvent (DES) of glucose and urea with the percentage composition of 60:40. The yields of these products were 82, 78, 75, 68, 72, 70 and 70 %, respectively. The products obtained were characterized by FT-IR and 1H NMR spectroscopic techniques. A synthesis of piperidin-4-one derivatives by using this green solvent was considered to be new environmentally safe synthetic method.

Preparation and Characterization of Photocatalytic TiO2/CdS Nanocomposite Loaded on Multi-Walled Carbon Nanotues (MWCNTs)

2012 ◽  
Vol 184-185 ◽  
pp. 1114-1119
Author(s):  
Ou Yang Ke ◽  
Xie Shan ◽  
Xiao Ou Ma
Keyword(s):  
Sol Gel ◽  
Pure Tio2 ◽  
Anatase Tio2 ◽  
Solar Irradiation ◽  
Simulated Solar Light ◽  
Solar Light Irradiation ◽  
Cubic Phases ◽  
Composite Photocatalysts ◽  
Simulated Solar Irradiation

Multi-walled carbon nanotues (MWCNTs)/TiO2/CdS composite photocatalysts were prepared by sol–gel method in order to investigate its photocatalytic activity under simulated solar irradiation. MWCNTs/TiO2/CdS composite photocatalysts were characterized by the methods of SEM, XRD, TG and UV–vis. The results showed that MWCNTs/TiO2/CdS composites were mainly composed of anatase-TiO2 and little CdS cubic phases. the composite can cause an pronounced red shift of UV–vis spectra compared with pure TiO2. The degradation of MO by MWCNTs/TiO2/CdS composite photocatalysts under simulated solar light irradiation was studied. The results showd that the presence of MWCNTs and CdS can enhance the photoefficiency of TiO2.

Sign in / Sign up

Export Citation Format

Share Document