Impact of UVA pre-radiation on UVC disinfection performance: Inactivation, repair and mechanism study

Xiao, Yao; Chu, Xiaona; He, Minghao; Liu, X.C.; Hu, Jiye

doi:10.1016/j.watres.2018.05.021

Cited by 72 publications

(42 citation statements)

References 40 publications

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“…While, 310 nm is still found to produce lesions in DNA that damage microorganisms. These findings are consistent with the other studies in literature [71,73]. Just open this same document with Adobe Reader.…”

Section: E Coli Inactivation Efficiencysupporting

confidence: 92%

“…Similarly, lower log inactivation of 0.92, 0.90 and 0.63 was also obtained in sequential irradiation of 267, 275 and 310 nm followed by the 370 nm UV-LED, respectively ( Figure 5). These results indicate that the 370 nm UV-LED irradiation could have functioned in repairing the already UV damaged DNA, rather than further damaging it [70,71]. This assumption could be possible since the 370 nm is within the range of photo-repair light, 300-480 nm [13,14].…”

Section: E Coli Inactivation Efficiencymentioning

confidence: 82%

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Effects of UV-LED Irradiation on E. coli in Water Disinfection

Nyangaresi¹,

Zhang²,

Shen³

2020

E. Coli Infections - Importance of Early Diagnosis and Efficient Treatment

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Ultraviolet light-emitting diode (UV-LED) is a newly emerging UV light source with a potential of replacing the conventional chemical methods, mercury UV lamps and xenon lamps in water disinfection applications. In this chapter, we will first give a general description on the status of E. coli disinfection in water by UV-LEDs. Then the main text will concentrate on our experimental studies. We will discuss the effects of single and combined UV-LED irradiation on E. coli in water, including the inactivation efficiency, the recover percentage after the UV-LED irradiation, the optimal wavelength for low energy consumption, differences in pulsed and continuous operations of UV-LEDs, effect of UVA-LED followed by UVC-LED irradiation and vice versa, and finally the effect of TiO 2-assisted photocatalytic disinfection.

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Section: E Coli Inactivation Efficiencysupporting

confidence: 92%

Section: E Coli Inactivation Efficiencymentioning

confidence: 82%

Effects of UV-LED Irradiation on E. coli in Water Disinfection

Nyangaresi¹,

Zhang²,

Shen³

2020

E. Coli Infections - Importance of Early Diagnosis and Efficient Treatment

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“…[29]. Our previous data were supported by Xiao Y., et al [30] and Song K., et al [31] who showed some synergistic inactivation effects on E. coli by the suppression of DNA repair using combined 265/365 nm UV-LED irradiations. However, some reports showed that the combination of 265/280 nm UV-LEDs had no synergistic effect on E. coli [17,31].…”

Section: Discussionsupporting

confidence: 63%

Irradiation by a Combination of Different Peak-Wavelength Ultraviolet-Light Emitting Diodes Enhances the Inactivation of Influenza A Viruses

Kojima

Mawatari

Emoto³

et al. 2020

Microorganisms

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Influenza A viruses (IAVs) pose a serious global threat to humans and their livestock. This study aimed to determine the ideal irradiation by ultraviolet-light emitting diodes (UV-LEDs) for IAV disinfection. We irradiated the IAV H1N1 subtype with 4.8 mJ/cm2 UV using eight UV-LEDs [peak wavelengths (WL) = 365, 310, 300, 290, 280, 270, and 260 nm)] or a mercury low pressure (LP)-UV lamp (Peak WL = 254 nm). Inactivation was evaluated by the infection ratio of Madin–Darby canine kidney (MDCK) cells or chicken embryonated eggs. Irradiation by the 260 nm UV-LED showed the highest inactivation among all treatments. Because the irradiation-induced inactivation effects strongly correlated with damage to viral RNA, we calculated the correlation coefficient (RAE) between the irradiant spectrum and absorption of viral RNA. The RAE scores strongly correlated with the inactivation by the UV-LEDs and LP-UV lamp. To increase the RAE score, we combined three different peak WL UV-LEDs (hybrid UV-LED). The hybrid UV-LED (RAE = 86.3) significantly inactivated both H1N1 and H6N2 subtypes to a greater extent than 260 nm (RAE = 68.6) or 270 nm (RAE = 42.2) UV-LEDs. The RAE score is an important factor for increasing the virucidal effects of UV-LED irradiation.

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“…It is difficult to precisely compare UV disinfection constants because the strains of E. coli, the source of the UV lamps (low-pressure or medium-pressure mercury lamps or UV-LED), and the irradiation apparatus are different among reports. The DUV-LED WW disinfection method described here offers a unique apparatus configuration, and this apparatus is different from other previously reported UV disinfection procedures, in which contaminated suspensions were placed in Petri dishes containing magnetic spin bars and rotated during UV exposure [18][19][20][21][22][23]32,33]. However, the disinfection constant obtained in this study, K EC = 0.37 (cm 2 /mJ), almost coincides with the most frequently reported values, such as 0.29 cm 2 /mJ by using a 260 nm LED [20], 0.37 cm 2 /mJ by using a 265 nm LED [34], and 0.303 cm 2 /mJ by using a 253.7 nm mercury vapor lamp [35].…”

Section: Theoretical Analysis Of the Disinfection Ratesmentioning

confidence: 99%

Instantaneous Water Purification by Deep Ultraviolet Light in Water Waveguide: Escherichia Coli Bacteria Disinfection

Matsumoto

Tatsuno

Hasegawa

2019

Water

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The necessity of small water purification equipment has been increasing in recent years as a result of frequent natural disasters. Ultraviolet (UV) radiation treatment is an effective method for the disinfection of bacterial contaminants in water. As an emerging technology, disinfection by deep-ultraviolet light-emitting diodes (DUV-LEDs) is promising. Few studies have used the point-source characteristics of LEDs and have instead replaced mercury vapor lamps with LEDs. Here, we demonstrate the instantaneous purification of contaminated water by combining the point source characteristics of DUV-LEDs with a water waveguide (WW). The principle is based on the WW region acting as an effective DUV disinfector, whereby a high UV dose in a confined WW region can be applied to bacterial contaminants in a short period of time (around one second). We demonstrate the effect of this DUV-LED WW disinfection technique by showing the results of 3-log disinfection levels of water contaminated with Escherichia coli bacteria after a short treatment time. We believe that the combination of the point-source nature of DUV-LED emission, the water-waveguide effect, and a small photovoltaic cell paves the way toward environmentally friendly and emergency preparedness portable water purification equipment that instantaneously supplies clean water just before drinking.

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Impact of UVA pre-radiation on UVC disinfection performance: Inactivation, repair and mechanism study

Cited by 72 publications

References 40 publications

Effects of UV-LED Irradiation on E. coli in Water Disinfection

Effects of UV-LED Irradiation on E. coli in Water Disinfection

Irradiation by a Combination of Different Peak-Wavelength Ultraviolet-Light Emitting Diodes Enhances the Inactivation of Influenza A Viruses

Instantaneous Water Purification by Deep Ultraviolet Light in Water Waveguide: Escherichia Coli Bacteria Disinfection

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