Influence of operating parameters on gas phase photocatalytic oxidation of methyl-ethyl-ketone in a light emitting diode (LED)-fluidized bed reactor

The effect of operating parameters on gas phase photocatalytic oxidation of methyl ethyl ketone (MEK) has been investigated over P25 and PC500 photocatalysts. The parameters were gas flow rate, relative humidity (RH), reaction temperature, and ultraviolet intensity. The photoreactor was composed of two LEDs matrices and a fluidized bed reactor (LED-FBR). No mass transfer limitation phenomena occurred at flow rates in the range 30–70 NL/h. The oxidation of MEK over the two photocatalysts did not highly depend on the presence or absence of humidity in the air stream. Temperature was determined as an important parameter in conversion of MEK over 60 to 120 °C, influencing also the selectivity to carbon dioxide and carbon monoxide. The simultaneous influence of RH and temperature was observed in the reaction at different temperatures and RHs, evidencing the decrease in the selectivity towards CO with increase of RH. With the increase of ultraviolet intensity, the rate of MEK oxidation increased over both catalysts, with the better activity of PC500 than P25 particularly at higher light intensities. The main effect of temperature was both to promote the MEK conversion and to limit the competitive water adsorption in the PCO reaction over the tested titanias.