UV-LEDs will become more efficient and will have a longer lifetime
[9] than low pressure mercury lamps which are currently widely
used in water treatment technologies. Typical low pressure mercury
lamps have a wall plug efficiency of 33–37%, depending on the
power of the lamps, and a lifetime of 12,000 h [10]. When these UVLEDs
can be integrated with wireless power transfer via inductive
coupling, an extensive variety of reactor designs for UV irradiation
can be imagined, even to the point of having autonomous free
moving UV-LEDs as in a fluidized bed. Hayashi et al. [11] showed
that LEDs dispersed in a reactor resulted in a higher photocatalytic
degradation rate compared to the LEDs that were fixed to
the wall of the reactor. The LEDs in the experiment of Hayashi
et al. [11] were powered with the piezoelectric effect by ultrasonic
waves