Adsorption using activated carbon (AC) and catalytic oxidation are two of the most common methods employed in controlling VOC emission. The combination of these two abatement techniques proves to be advantageous, especially for low-temperature VOC oxidation.
Four catalysts were prepared using two types of activated carbon, namely, a commercially available activated carbon (AC1) and ITDI-manufactured activated carbon (AC2). The catalysts, namely, CeO2/AC1, CeO2/AC2, CoO/AC1, and CoO/AC2, were prepared using the incipient-wetness method. The ignition temperatures of the ACs were determined and a representative of the four catalysts was used.
The activity of each of the catalyst was assessed in the oxidation of a representative VOC, which is xylene, using a flow reactor system equipped with a gas chromatography apparatus. The activity was measured in terms of the percentage conversion of xylene, selectivity to CO2 over CO, and yield of CO2.
The catalysts were found to have activity even at relatively low temperatures of 200-250°C. It was found out that the ranking of the catalysts tested for xylene oxidation at 200oC, in terms of xylene conversion and yield of CO2, was as follows: CeO2/AC1> CoO/ AC1> CeO2/AC2> CoO/ AC2. For all the catalysts tested, the selectivity to CO2 over CO was found to be 100% at 200°C.
The results of the study may be vital for the development of a catalytic oxidizer with an efficient catalyst for the reduction or elimination of minute concentrations of VOCs in the air.