Treatment of hospital indoor air by a hybrid system of combined plasma with photocatalysis: Case of trichloromethane

Abstract

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

Indoor air treatment of refrigerated food chambers with synergetic association between cold plasma and photocatalysis: Process performance and photocatalytic poisoning

“…A digital oscilloscope (Lecroy Wave Surfer 24 Xs, 200 MHz) allows visualizing the high voltage applied and the voltage across the capacity. The electrical system of the NTP reactor has been described in detail in our previous work[26]. Schematic view of the annular reactor coupling photocatalysis and NTP for the treatment of the air in a refrigerated room.…”

Integrated process for the removal of indoor VOCs from food industry manufacturing: Elimination of Butane-2,3-dione and Heptan-2-one by cold plasma-photocatalysis combination

“…Heptan-2-one presents a long molecular chain (C7H14O), harder to degrade using photocatalytic treatment, which explains the decreasing trend of the efficiency. [20], aromatics [27] and aldehydes [25], respectively. The effect of humidity on mixtures was also studied and the results are discussed below (see part 3.1.3., Figure 5).…”

“…The best improvement in this study is 5.7%, but this is simply because the energy applied to the plasma is low (only 4.5 JL −1 ). We have shown in our previous studies [12,18,20,21,29,30] that the COV removal efficiency is clearly improved by coupling plasma and photocatalysis when using higher energies, but the use of high energy generates a significant amount of ozone [25], which is not desired in our current case of indoor air treatment.…”

“…DBD plasma was created by applying high voltage power via a signal generator (BFi OPTILAS (SRS) reference DS 335/1). The applied voltage, as a sinusoidal waveform of 10V, was then amplified to 30 kV by an amplifier (TREK 30A/40) [20,[22][23][24][25]. This amplifier is connected to the reactor outer/inner electrodes, in a copper and Al grid form for the outer and inner electrodes, respectively.…”

“…However, each method used alone can present some limitations: (i) accumulation of residues on the catalyst surface leads to a gradual decrease in photocatalytic activity, which regularly requires a regeneration step [11][12][13] and (ii) a low CO2 selectivity was observed via plasma treatment and also (iii) undesirable by-product formation (carbon monoxide CO and ozone O3) [14,15], each of them constitutes significant limitations which limit single mode usage. Therefore, it is better to associate photocatalysis and plasma together to ensure (i) high treatment efficiency and (ii) overcome existing disadvantages [16][17][18][19][20][21][22]. In this context, several studies have focused on the oxidation of VOCs via photocatalysis-plasma technologies and reported that an enhancement of more than 10% was observed on removal efficiency of malodorous pollutant exhaust from animal quartering centers like ammonia (NH3), dimethyl disulfide (CH3SSCH3) and butyraldehyde (C4H8O) [12,18].…”