Influence of environmental parameters on the photocatalytic oxidation efficiency of acrylonitrile and isoflurane; two operating room pollutants

International audienceIn hospitals, operating rooms (ORs) are very demanding in terms of the indoor air quality (IAQ) and require systems that minimize the concentrations of pollutants (microorganisms, chemical and particulate matter). Air treatment devices that use photocatalytic oxidation (PCO) could potentially be used in the OR to improve IAQ. In this work, the fate of two OR pollutants acrylonitrile (chemical found in surgical smoke) and isoflurane (an-esthetic gas) when they go through a PCO device was investigated. The experiments were conducted in a laboratory closed loop multi-pass reactor. A mathematical model was utilized to enable the calculation of one indicator (single-pass removal efficiency) for acrylonitrile and two indicators (induction period and single-pass removal efficiency) for isoflurane. The degradation efficiency was then accessed by studying the influence of environmental parameters on these indicators. The parameters that were studied are the relative humidity, presence of co-pollutants and presence of particles. The parameters were observed to have similar effects on the degradation of both compounds. Increasing relative humidity inhibited the degradation probably due to competitive adsorption. The presence of co-pollutants like nitrous oxide and acetic acid caused a possible competition for adsorption unto active sites thus decreased the degradation efficiency of acrylonitrile and isoflurane. The increase in the concentration of the co-pollutants enhances the competitive effect and further decreases the degradation efficiency of the target pollutants. Finally the presence of particles on the photocatalytic media could block active sites thereby inhibiting the degradation of acrylonitrile and isoflurane