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Bench-scale evaluation of water disinfection by visible-to-UVC upconversion under high-intensity irradiation

Paper ID Volume ID Publish Year Pages File Format Full-Text
30147 44460 2015 7 PDF Available
Title
Bench-scale evaluation of water disinfection by visible-to-UVC upconversion under high-intensity irradiation
Abstract

•Visible-to-UVC upconversion ceramics were used to disinfect water for the first time•Under 840-mW laser excitation, E. coli showed ~ 4-log inactivation in 20 min•Photoreactivation caused by the laser slowed upconversion-induced UVC disinfection•Sunlight experiments showed that no additional inactivation was attributed to upconversion

The feasibility of applying visible-to-UVC upconversion (UC) luminescence to enhance the kinetics of solar water disinfection was evaluated using Lu7O5F9:Pr3 + ceramics incorporated into a solar reactor containing E. coli suspensions. Inactivation was assessed in batch conditions using both laser and lens-concentrated sunlight excitation conditions. Under 840-mW argon laser excitation, the UC efficiency was estimated to be 1 order of magnitude greater than previously reported under lamp excitation and UVC emitted by the reactors resulted in 3.6-log inactivation in 20 min. However, experiments using ~ 1500 mW of concentrated natural sunlight showed no additional inactivation that could be attributed to UC within the timescale studied. Due to the fundamental and practical limitations of solar focusing, the optical concentration ratio employed herein prevented the excitation beam from achieving the power densities required to attain UC efficiencies comparable to the laser experiments. We also observed that the high intensity of both the laser and sunlight induced rapid photoreactivation by the bacteria, which detracted from net disinfection performance. The results suggest that current UC materials perform inadequately for environmental application; nonetheless, valuable qualitative and quantitative insight was gained that more explicitly defines materials development goals and considerations for application of UC to environmental technology.

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Keywords
Ln3 +,  lanthanide; LOF, lutetium oxyfluoride (Lu7O6F9); PLS, photoluminescence spectroscopy; PMT, photomultiplier tube; SODIS, solar water disinfection; UC, upconversion luminescenceUpconversion; UVC; Solar; Disinfection; Praseodymium; Photoreactivation
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Bench-scale evaluation of water disinfection by visible-to-UVC upconversion under high-intensity irradiation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 153, December 2015, Pages 405–411
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us