A hybrid system combining plasma with photocatalysis for treatment of refrigerated food chambers.
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•A possible way to treat the air in refrigerated food chambers is ...proposed.•Non-thermal plasma was coupled to photocatalysis for indoor air treatment.•The impact of the operating parameters on performance of the process are tested.•The removal of propionic acid and benzene each alone and in mixture are studied.•Poisoning and catalyst regeneration capacity with non-thermal plasma is studied.
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 TiO2-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 CO2 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.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
An hybrid system of combined plasma with photocatalysis for treatment of hospital indoor air.
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•A possible way for treatment of air from hospitals and swimming pools is proposed.•The ...destruction of CVOC in air by photocatalysis and plasma and coupling is studied.•The synergistic effect of the combined system is observed.•The effects of operating parameters on the performance of each process are tested.•TiO2 + UV showed high performance in the mineralization and ozone elimination.
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 (CHCl3) 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 (2–8 m3 h−1), relative humidity of the effluent (5, 30, 50 and 90%) as well as input of the plasma discharge (9–21 kV) on the photodegradation of trichloromethane is investigated.
Our findings show that the increase of flow rate leads to a reduction of degradation efficiency, while the humidity promotes the degradation in the case of photocatalysis process due to the formation of OH radicals.
Moreover, the addition of a photocatalyst under UV radiation in the discharge zone enhances the reduction of ozone and CO gases compared to plasma process alone.
The combination of plasma DBD and photocatalysis enhances the removal efficiency with a synergetic effect, leading to removal efficiency higher than 10% if we consider the sum of the contribution of each process separately.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This article reports a study of the thermo-oxidation and biodegradation in the soil of low-density polyethylene/starch films (LDPE/starch) by infrared spectroscopy: Films of LDPE/Starch blends of ...different composition (starch content range from 0 to 15% w/w),were prepared and exposed to thermo-oxidation at different temperatures at 80, 90 and 100°C,and buried in the soil of public dump during 300 days. The oxidation, for films subjected to thermal oxidation, was revealed by the appearance of absorption bands of carbonyl groups centered at 1715 cm-1. After the induction period, which varies from 12 to 14 days according to the concentration of starch incorporated in the films, the indication of carbonyl croup increases with time and temperature of exposition. During the first 30 days, the rate of oxidization is the weaker, the larger percentage of starch in the film of LDPE. The biodegradation of films buried in the soil for 300 days, was followed by infrared spectroscopy. The carbonyl index calculated at 1715 cm-1 and at 1744 cm-1 showed the oxidation of films LDPE/starch. This index increases with time of burial and starch percentage incorporated into LDPE films during the first 180 days in soil burial, then decreases.
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