Effect of visible light exposure on E. Coli treated with pulsed UV-rich light

Author(s):  
S. J. MacGregor Y. Lamont
Keyword(s):  
2020 ◽  
Vol 10 (2) ◽  
Author(s):  
Ameer Baig Ali Baig ◽  
Vadamalar Rathinam ◽  
Jayanthi Palaninathan

AbstractZr-doped SnO2 (Zr:SnO2) nanostructures (NSs) were produced by simplistic and low-cost co-precipitation route. The FTIR spectra of bands on 523 and 583 cm−1 were witnessed though indorsed as the features of (Sn–OH) term which approves the incident of Sn–O in the synthesized samples. The Zr:SnO2 NSs were spherical-like and composed of numerous agglomerated particles. The decreased crystallite sizes of the pristine and Zr-doped SnO2 NPs were 41.9, 38.9 and 35.8 nm individually. Moreover, the achievable growth manner of acquired samples was deliberated through the source of the customs of nucleation and crystal growth. The photocatalytic performances of 4% of Zr-doped SnO2 nanoparticles (NPs) were thoroughly explored in the photodegradation of methyl orange (MO) dye, thus revealing higher photocatalytic activity in the degradation of MO than pristine and 2% of Zr-doped SnO2 under via visible-light exposure. Related to pristine SnO2, the 4% Zr-doped SnO2 NPs are accessible to greater photocatalytic capability, which could be essentially accredited to existing in the nominal defects of oxygen vacancies by the produced NPs. Eventually, founded on the self-assembly progression the possible development of photocatalytic mechanism was projected by means of reactive species in trapping tests as well. Also, the antibacterial action was attained against E. coli and S. aureus bacteria through agar well diffusion system.


2019 ◽  
Vol 8 (1) ◽  
pp. 56-61
Author(s):  
Aneeya K. Samantara ◽  
Debasrita Dash ◽  
Dipti L. Bhuyan ◽  
Namita Dalai ◽  
Bijayalaxmi Jena

: In this article, we explored the possibility of controlling the reactivity of ZnO nanostructures by modifying its surface with gold nanoparticles (Au NPs). By varying the concentration of Au with different wt% (x = 0.01, 0.05, 0.08, 1 and 2), we have synthesized a series of (ZnO/Aux) nanocomposites (NCs). A thorough investigation of the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface has been carried out. It was observed that ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity among all concentrations of Au on the ZnO surface, which degrades the dye concentration within 2 minutes of visible light exposure. It was further revealed that with an increase in the size of plasmonic nanoparticles beyond 0.08%, the accessible surface area of the Au nanoparticle decreases. The photon absorption capacity of Au nanoparticle decreases beyond 0.08% resulting in a decrease in electron transfer rate from Au to ZnO and a decrease of photocatalytic activity. Background: Due to the industrialization process, most of the toxic materials go into the water bodies, affecting the water and our ecological system. The conventional techniques to remove dyes are expensive and inefficient. Recently, heterogeneous semiconductor materials like TiO2 and ZnO have been regarded as potential candidates for the removal of dye from the water system. Objective: To investigate the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface and the effect of the size of Au NPs for photocatalytic performance in the degradation process. Methods: A facile microwave method has been adopted for the synthesis of ZnO nanostructure followed by a reduction of gold salt in the presence of ZnO nanostructure to form the composite. Results: ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity which degrades the dye concentration within 2 minutes of visible light exposure. The schematic mechanism of electron transfer rate was discussed. Conclusion: Raspberry shaped ZnO nanoparticles modified with different percentages of Au NPs showed good photocatalytic behavior in the degradation of dye molecules. The synergetic effect of unique morphology of ZnO and well anchored Au nanostructures plays a crucial role.


ChemCatChem ◽  
2019 ◽  
Vol 11 (14) ◽  
pp. 3307-3317
Author(s):  
Andreea L. Chibac ◽  
Violeta Melinte ◽  
Vlasta Brezová ◽  
Estelle Renard ◽  
Arnaud Brosseau ◽  
...  

RSC Advances ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 6383-6394 ◽  
Author(s):  
Haishuai Li ◽  
Linlin Cai ◽  
Xin Wang ◽  
Huixian Shi

A noval ternary nanocomposite AgCl/Ag3PO4/g-C3N4 was successfully synthesized for photocatalytic degradation of methylene blue, methylparaben and inactivation of E. coli under visible light irradiation, showing excellent photocatalytic degradation performance and stability.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoyu Zhao ◽  
Ye Zhao ◽  
Ming-De Li ◽  
Zhong’an Li ◽  
Haiyan Peng ◽  
...  

AbstractPhotopolymerization-based three-dimensional (3D) printing can enable customized manufacturing that is difficult to achieve through other traditional means. Nevertheless, it remains challenging to achieve efficient 3D printing due to the compromise between print speed and resolution. Herein, we report an efficient 3D printing approach based on the photooxidation of ketocoumarin that functions as the photosensitizer during photopolymerization, which can simultaneously deliver high print speed (5.1 cm h−1) and high print resolution (23 μm) on a common 3D printer. Mechanistically, the initiating radical and deethylated ketocoumarin are both generated upon visible light exposure, with the former giving rise to rapid photopolymerization and high print speed while the latter ensuring high print resolution by confining the light penetration. By comparison, the printed feature is hard to identify when the ketocoumarin encounters photoreduction due to the increased lateral photopolymerization. The proposed approach here provides a viable solution towards efficient additive manufacturing by controlling the photoreaction of photosensitizers during photopolymerization.


2017 ◽  
Vol 4 (11) ◽  
pp. 11671-11678
Author(s):  
M. Giridhar ◽  
H.S. BhojyaNaik ◽  
R. Vishwanath ◽  
C.N. Sudhamani ◽  
M.C. Prabakar ◽  
...  

2017 ◽  
Author(s):  
Tatyana Perlova ◽  
Martin Gruebele ◽  
Yann R. Chemla

AbstractBlue light has been shown to elicit a tumbling response inE. coli, a non-phototrophic bacterium. The exact mechanism of this phototactic response is still unknown, and its biological significance remains unclear. Here, we quantify phototaxis inE. coliby analyzing single-cell trajectories in populations of free-swimming bacteria before and after light exposure. Bacterial strains expressing only one type of chemoreceptor reveal that all fiveE. colireceptors - Aer, Tar, Tsr, Tap and Trg - are capable of mediating a response to light. In particular, light exposure elicits a running response in Tap-only strain, the opposite of the tumbling response observed for all other strains. Light therefore emerges as a universal stimulus for allE. colichemoreceptors. We also show that blue light exposure causes a reversible decrease in swimming velocity, a proxy for proton motive force. We hypothesize that rather than sensing light directly, chemoreceptors sense light-induced perturbations in proton motive force.ImportanceOur findings provide new insights on the mechanism ofE. coliphototaxis, showing that all five chemoreceptor types respond to light and that their interactions play an important role in cell behavior. Our results also open up new avenues for examining and manipulatingE. colitaxis. Since light is a universal stimulus, it may provide a way to quantify interactions between different types of receptors. Since light is easier to control spatially and temporally than chemicals, it may be used to study swimming behavior in complex environments. Since phototaxis can cause migration ofE. colibacteria in light gradients, light may be used to control bacterial density for studying density-dependent processes in bacteria.


2012 ◽  
Vol 03 (04) ◽  
pp. 421-430 ◽  
Author(s):  
Yanyan Yao ◽  
Kentaro Yamauchi ◽  
Goro Yamauchi ◽  
Tsuyoshi Ochiai ◽  
Taketoshi Murakami ◽  
...  

2018 ◽  
Vol 42 (17) ◽  
pp. 14229-14238 ◽  
Author(s):  
Joyee Mitra ◽  
Manav Saxena ◽  
Navendu Paul ◽  
Ekata Saha ◽  
Rudra Sarkar ◽  
...  

An easily separable graphene oxide–molybdenum oxo-bis(dithiolene) ([Ph4P]2[MoO(S2C2(CN)2)2]) composite degraded Rhodamine B and Rose Bengal dye upon visible light exposure.


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