A calibrated UV-LED based light source for water purification and characterisation of photocatalysis

• DOI: 10.1039/c7pp00269f
• Publication Date: 2017-10-16T07:58:46Z
• Authors: A. Sergejevs; C. T. Clarke; D. W. E. Allsopp; J. Marugan; A. Jaroenworaluck; W. Singhapong; P. Manpetch; R. Timmers; C. Casado; C. R. Bowen
• Keywords: Ultraviolet; Light intensity; Titanium Dioxide; Ultraviolet light

Photocatalysis has a potential to become a cost effective industrial process for water cleaning. One of the most studied photocatalysts is titanium dioxide which, as a wide band gap semiconductor, requires ultraviolet (UV) light for its photoactivation. This is at the wavelengths where the efficiency of present-day light emitting diodes (LEDs) decreases rapidly, which presents a challenge in the use of UV-LEDs for commercially viable photocatalysis. There is also a need for accurate photocatalysis measurement of remediation rates of water-borne contaminants for determining optimum exposure doses in industrial applications. In response to these challenges, this paper describes a UV-LED based photocatalytic test reactor that provides a calibrated adjustable light source and pre-defined test conditions to remove as many sources of uncertainty in photocatalytic analysis as possible and thereby improve data reliability. The test reactor provides a selectable intensity of up to 1.9 kW m-2 at the photocatalyst surface. The comparability of the results is achieved through the use of pre-calibration and control electronics that minimize the largest sources of uncertainty; most notably variations in the intensity and directionality of the UV light emission of LEDs and in LED device heating.