The purpose of this study is to evaluate the efficiency of non-thermal plasma and heterogeneous photocatalysis processes for indoor air treatment using cylindrical continuous reactor at pilot scale and high flow rates. Trichloromethane (CHCl 3) also called chloroform was chosen as a model pollutant representing hospital indoor air. This pollutant is considered as carcinogenic, mutagenic and reprotoxic agent. The effect of several parameters such as inlet pollutant concentrations (25-300 mg m-3), flow rates (2 to 8 m 3 h-1
The purpose of this study is to evaluate the efficiency of non-thermal plasma (NTP) and heterogeneous photocatalytic processes for indoor air treatment of refrigerated food chambers. Propionic acid and benzene were chosen as target pollutants to simulate odors inside a fridge. Firstly, the microstructure of the used catalyst was investigated by transmission electron microscopy (TEM). The influence of operating parameters such as pollutant concentration, type of system (mono-compound or bi-compound system), duration of photocatalytic degradation and relative humidity in the indoor air were investigated. Our findings show a synergetic effect between NTP and photocatalysis for malodors removal. Additionally, the mineralization of pollutant is directly controlled by the amount of ozone produced by the plasma discharge then it decomposes on the TiO 2-based catalytic surface. Our results highlight also the key role of the generated reactive oxygen species (hydroxyl radials and atomic oxygen) in (i) propionic acid and benzene removal, (ii) selectivity of CO 2 and CO, (iii) by-products formation such as ozone formation. Moreover, the recovery of the initial photocatalytic activity was explored in details. A significant poisoning occurred when photocatalysis was carried out alone for the degradation of propionic acid and benzene. Results confirm that NTP plasma enhanced the photocatalytic activity. We also showed the effect of NTP plasma on the regeneration of the photocatalytic surface.
International audienceHydrogen sulfide (H2S) is currently removed from gaseous effluents by chemical scrubbing using water. Chlorine is a top-grade oxidant, reacting with H2S with a fast kinetic rate and enhancing its mass transfer rate. To design, optimize and scale-up scrubbers, knowledge of the reaction kinetics and mechanism is requested. This study investigates the H2S oxidation rate by reactive absorption in a mechanically agitated gas-liquid reactor. Mass transfer (gas and liquid sides mass transfer coefficients) and hydrodynamic (interfacial area) performances of the gas-liquid reactor were measured using appropriated physical or chemical absorption methods. The accuracy of these parameters was checked by modeling the H2S absorption in water without oxidant. A sensitivity analysis confirmed the robustness of the model. Finally, reactive absorption of H2S in chlorine solution for acidic or circumneutral pH allowed to investigate the kinetics of reaction. The overall oxidation mechanism could be described assuming that H2S is oxidized irreversibly by both hypochlorite anion ClO- (k = 6.75 106 L mol-1 s-1) and hypochlorous acid ClOH (k = 1.62 105 L mol-1 s-1)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.