The use of light-emitting diode (LEDs) in water and wastewater treatment: A short review

Nowadays, the shortage of clean water cause to treat and reuse the polluted water for different purposes. Many approach for treatment of wastewater are available such as activated sludge, membrane, adsorption and advanced oxidation photocatalysis (AOPs). Photocatalysis is one the most efficient method for treatment of water and wastewater in which the polluted flow is passing under the UV-radiation. Today, the UV-Ray can be supplied from some sources such as Pulsed UV lamps (PUV), Excimer UV lamps, microwave electrodeless discharge lamps (EDL) and Ultraviolet light emitting diodes (LED). Mercury lamps as an early used energy-source have many damaging characteristic such as toxicity, limited lifetime, low flexibility and high energy consumption. However, because of a weak radiant flux, the time of irradiation for treatment should be increased. LEDs have no disadvantages that the other kind have. The advantages of LEDs such as non-toxic, long lifetime, flexibility and low energy consumption has made it an exclusive innovation. This technology has solved the environmental problems caused by the use of mercury bulbs. The recent studies have investigated the application of UV-LEDs in photocatalytic process, AOPs based on photo-Fenton and disinfection. All of the results have demonstrated that the degradation of pollutants under the UV-LEDs had a high efficiency. However, most of the studies have not investigated related to any weakness or limitations on using UV-LEDs in any photoreactor for wastewater treatment; therefore, the environmental researchers need to investigate the disadvantages and limitations of using LED in photoreactors and how to industrialize this technology

کلیدواژه ها:

UV- LED ، AOPs ، Water treatment ، Photocatalyst ، Photo-Fenton