In this work, we investigated the impacts of atmospheric pressure dielectric barrier discharge (DBD), i.e., plasma treatment, on pearl millet seeds germination and plant growth. The effect of plasma ...discharge on water activation, by introducing the reactive species, was explored. We evidenced that about 30 min plasma treated pearl millet seeds exhibited 20% higher germination rate than the control seed watered with tap water. The HR-SEM study revealed that the plasma treatment increased the roughness and FTIR study showed that new oxygen functional groups were introduced on the seed surface. Moreover, it was observed that the water contact angle decreased for plasma treated seeds (50%) and the water uptake also increased considerably as compared to control seeds. These findings indicate that the seed surface has turned more hydrophilic after plasma treatment. A cylindrical double dielectric barrier discharge (D-DBD) reactor was employed for water activation, and 30 min of treatment under air has decreased the pH of deionized water from 7.4 to 4.5 and produced about 1.78 ppm of nitrate (NO
3
−
) and 4.2 ppm of hydrogen peroxide (H
2
O
2
). Interestingly, the plasma activated water (PAW) improved the pearl millet seed germination by 30% (after 24 h of sowing) and plant growth as compared to tap water and deionized water. Remarkably, when PAW and plasma-treated seeds were combined, a beneficial impact in seed germination (95 ± 2%) and seedling growth have been evidenced owing to synergistic effect. We evidenced that among the long-lived species in PAW, NO
3
−
enhanced the seed germination and plant growth under similar conditions. These findings demonstrate that the proposed cold plasma reactors could be utilized to boost seed germination and plant growth.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 4 Given name: Amine Aymen Last name Assadi. Also, kindly confirm the details in the metadata are correct.Yes, all author names are correctly editted.
The combined effect of non-thermal plasma treatment of water and seeds on the rate of germination and plants growth of radish (
Raphanus sativus
), tomato (
Solanum lycopersicum
), and sweet pepper (
...Capsicum annum
) have been investigated using dielectric barrier discharges in air under atmospheric pressure and room temperature. A cylindrical double dielectric barrier discharge reactor is used for water activation and a plate-to-plate double DBD reactor is employed for seed treatment. The activation of water, for 15 and 30 min, lead to acidic solutions (pH 3) with moderate concentrations of nitrate (NO
3
−
) and hydrogen peroxide (H
2
O
2
). Plasma activated water (PAW) has shown a significant impact on germination as well as plant growth for the three types of seeds used. Interestingly, the positive effect, in seed germination and seedling growth, has been observed when the PAW and plasma-treated seeds (10 and 20 min) were combined. In one hand, when the seeds were (tomato and pepper) exposed to 10 min plasma and watered with PAW-15 for first 9 days followed by tap water for 51 days, the stem length is increased about 60% as compared to control sample. On the second hand, for longer exposures of seeds and water to plasma discharges, a negative effect is observed. For instance, plasma-treated seeds watered with PAW-30, the plant growth and vitality were decreased as compared to control sample. These results revealed that the developed cold plasma reactors could be used to significantly improve the seed germination as well as plant growth, nevertheless, the plasma treatment time has to be optimized for each seeds.
Seed germination and plants growth are significantly improvement by combining plasma activated water and plasma treated seeds.
Mineralization of gaseous chlorobenzene (major VOC from cement plants) was studied in a continuous reactor using three advanced oxidation processes: (i) photocatalysis, (ii) Dielectric Barrier ...Discharge (DBD) plasma and (iii) DBD/TiO2-UV coupling. The work showed an overproduction of OH * and O * radicals in the reaction medium due to the interaction of Cl * and O3. A parametric study was carried out in order to determine the evolution of the removal efficiency as a function of the concentration, the flow rate and the applied voltage. Indeed, a variation of the flow rate from 0.25 to 1 m3/h resulted in a decrease in the degradation rate from 18 to 9%. Similarly, an increase in concentration from 13 to 100 mg/m3 resulted in a change in degradation rate from 18 to 4%. When the voltage was doubled from 6 to 12 kV, the degradation rate varied from 22 to 29 % (plasma) and from 53 to 75% (coupling) at 13 mg/m3. The evolution of COX and O3 was monitored during the experiments. When the voltage was doubled, the selectivity increased from 28 to 37% in the plasma alone and from 48 to 62 % in the coupled process. In addition, at this same voltage range, the amount of ozone formed varied from 10 to 66 ppm in plasma and 3 to 29 ppm in coupling. This degradation performance can be linked to a synergistic effect, which resulted in an increase in the intensity of the electric field of plasma by the TiO2 and the improvement in the performance of the catalyst following the bombardment of various high-energy particles of the plasma.
The present study combines nonthermal plasma (NTP) and thermal catalysis to exploit the synergism for direct conversion of CO2 to CH3OH using H2. Series of catalyst, that is, CuO/QW, NiO/QW, ...Fe2O3/QW, NiO/Fe2O3/QW, CuO/Fe2O3/QW have been tested for CO2 conversion and CH3OH selectivity. And it was observed that 5 wt% CuO/Fe2O3/QW exhibited better CO2 conversion and CH3OH selectivity as compared to other catalysts. With 5 wt% CuO/Fe2O3/QW, at 200°C and 2‐W NTP input power (100 ml/min feed flow and 1:3 ratio of CO2 and H2) about 16.7% CO2 conversion and 32.7% CH3OH selectivity have been reached. Indeed, the highest of 9.32 mmol h−1 gcat−1 of CH3OH space‐time yield is obtained over CuO/Fe2O3/QW, which is about two times higher than the reported value in the literature (4.41 mmol h−1 gcat−1 of CH3OH using Cu/ZnO/Al2O3, 30°C, feed flow 40 ml/min, and 30‐W input power).
The direct conversion of CO2 to CH3OH using H2 on a bifunctional catalytic system (CuO/Fe2O3/QW and NiO/Fe2O3/QW) has been explored. A synergistic effect is observed between the plasma and thermal catalytic process. About 16.7% CO2 conversion and 32% of CH3OH selectivity have been reached with 2‐W input power at 200°C. Indeed, the highest of 9.32 mmol h−1 gcat−1 of CH3OH space‐time yield is obtained over CuO/Fe2O3/QW, which is about two times higher than the reported value in the literature.
Abstract
The present study combines nonthermal plasma (NTP) and thermal catalysis to exploit the synergism for direct conversion of CO
2
to CH
3
OH using H
2
. Series of catalyst, that is, CuO/QW, ...NiO/QW, Fe
2
O
3
/QW, NiO/Fe
2
O
3
/QW, CuO/Fe
2
O
3
/QW have been tested for CO
2
conversion and CH
3
OH selectivity. And it was observed that 5 wt% CuO/Fe
2
O
3
/QW exhibited better CO
2
conversion and CH
3
OH selectivity as compared to other catalysts. With 5 wt% CuO/Fe
2
O
3
/QW, at 200°C and 2‐W NTP input power (100 ml/min feed flow and 1:3 ratio of CO
2
and H
2
) about 16.7% CO
2
conversion and 32.7% CH
3
OH selectivity have been reached. Indeed, the highest of 9.32 mmol h
−1
gcat
−1
of CH
3
OH space‐time yield is obtained over CuO/Fe
2
O
3
/QW, which is about two times higher than the reported value in the literature (4.41 mmol h
−1
gcat
−1
of CH
3
OH using Cu/ZnO/Al
2
O
3
, 30°C, feed flow 40 ml/min, and 30‐W input power).
The hydrogenation of CO2 to CH3OH on the binary mixed metal oxides of CuO–Fe2O3 under nonthermal plasma discharge has been reported in this study. The catalysts are synthesized using the sol–gel ...route and characterized by XRD, FTIR, SEM, and XPS techniques. The impact of CuO mixing with Fe2O3 on CO2 conversion and CH3OH yield has been investigated. Herein, we have compared two distinct techniques, namely thermal and plasma catalytic processes. The overall outcome shows that the CO2 conversion and CH3OH production increase with an increase in CuO mixing with Fe2O3. The synthesized catalyst does not show significant CO2 conversion and CH3OH formation in the thermal catalytic process (100–250 °C). Interestingly, when plasma discharge is combined with thermal heating, CO2 conversion and CH3OH production significantly improve. The plasma discharges in the CO2/H2 gas stream, at low temperatures (<200 °C), reduce Cu+2 to Cu+1 and Fe+3 to Fe+2, which could probably enhance the CO2 conversion and CH3OH production. Among the catalysts prepared, 15% CuO–Fe2O3 exhibited the best catalytic activity with 13.2% CO2 conversion, 7.3% CH3OH yield, and a space–time yield of 13 mmolCH3OH/h gcat, with 4.67 kJ/L of specific input energy (SIE). The CH3OH space–time yield is 2.9-fold higher than that of the commercial catalyst Cu/ZnO/Al2O3, which is operated at 30 °C with 45.45 kJ/L SIE.
The hydrogenation of CO
to CH
OH on the binary mixed metal oxides of CuO-Fe
O
under nonthermal plasma discharge has been reported in this study. The catalysts are synthesized using the sol-gel route ...and characterized by XRD, FTIR, SEM, and XPS techniques. The impact of CuO mixing with Fe
O
on CO
conversion and CH
OH yield has been investigated. Herein, we have compared two distinct techniques, namely thermal and plasma catalytic processes. The overall outcome shows that the CO
conversion and CH
OH production increase with an increase in CuO mixing with Fe
O
. The synthesized catalyst does not show significant CO
conversion and CH
OH formation in the thermal catalytic process (100-250 °C). Interestingly, when plasma discharge is combined with thermal heating, CO
conversion and CH
OH production significantly improve. The plasma discharges in the CO
/H
gas stream, at low temperatures (<200 °C), reduce Cu
to Cu
and Fe
to Fe
, which could probably enhance the CO
conversion and CH
OH production. Among the catalysts prepared, 15% CuO-Fe
O
exhibited the best catalytic activity with 13.2% CO
conversion, 7.3% CH
OH yield, and a space-time yield of 13 mmol
/h g
, with 4.67 kJ/L of specific input energy (SIE). The CH
OH space-time yield is 2.9-fold higher than that of the commercial catalyst Cu/ZnO/Al
O
, which is operated at 30 °C with 45.45 kJ/L SIE.
•NTP discharge initiates the CO2 dissociation to CO.•NiO nano catalyst assist the hydrogenation of CO on the catalyst surface.•NTP discharge enhances the CO2 to CH4 formation at 250 °C.•High ...operating temperature assist the water gas shift reaction and partial oxidation of CH4 to CO.•Several hours of plasma discharge does not change the catalyst morphology.
Modernization, deforestation and overwhelmingly growing world population are significantly increasing the atmosphere CO2 level. The conversion of CO2 to other products has attracted much more attention, especially atmospheric pressure cold plasma for CO2 conversion to CH4. In this study the hydrogenation of CO2 to CH4 was carried out using Ni/γ-Al2O3 nanocatalyst coupled non-thermal plasma dielectric barrier discharge reactor (NTP-DBD). The effect of temperature, plasma input power on CO2 conversion rate and CH4 selectivity have been studied. It was evidenced that, compared to conventional thermal catalysis (300 °C), plasma-catalysis has shown temperature shift (T shift) of 50 °C (250 °C). Furthermore, at 250 °C, 10wt.%Ni/γ-Al2O3 nanocatalyst has shown about 40% CO2 conversion and 70% CH4 selectivity with 340 J.L−1 specific input energy (SIE). At low operating temperature, increase in SIE increases the CO2 conversion and CH4 selectivity by about 10%. The SEM and EDX analysis evidenced that NiO is homogeneously dispersed on the alumina beads surface. The TEM analysis before and after catalytic experiments showed that the average “NiO” particle size is 10–12 nm and 12–15 nm, respectively. The plasma discharge slightly increases the Ni particle size, however, it does not affect neither CO2 conversion and nor CH4 selectivity.
•Characterization of VOC non-thermal plasma treatment under typical indoor air conditions.•Comparison of continuous and sequential processes with the same packed bed reactor.•Assessment of side ...product generation by both processes at ppb-levels.•Experimental evidence of the lower energy demand of the sequential process.
MnXOY coated glass beads packed bed non-thermal plasma (NTP) reactor has been designed and operated for isopropanol (IPA) removal close to indoor air conditions. The IPA removal efficiency of continuous NTP treatment is compared with the sequential approach, i.e. adsorption of IPA on MnXOY and subsequent regeneration of the saturated MnXOY surface by non-thermal plasma. The comparison between both approaches has been achieved with the same packed bed reactor and model VOC under equivalent indoor air conditions. Firstly, based on carbon mass balance calculations, the continuous treatment has shown better performances from an IPA abatement point of view, as well as from a mineralization point of view. However, the characterization of ppb level side-products evidenced that the continuous treatment leads to a more significant release of organic side products which may impact indoor air quality. Secondly, both processes have been compared in terms of energetic costs regarding (i) IPA removal, and (ii) CO2 formation. Interestingly, it is evidenced that, to treat the same amount of IPA, the sequential approach requires 14.5 times less energy than the continuous NTP treatment process. Similarly, to produce the same amount of CO2, the sequential approach consumes 10 times less energy. This comparison evidences the interest of adsorption combined with subsequent non-thermal plasma regeneration for indoor air effluent treatment.
A nonthermal plasma surface discharge (NPSD) coupled with photocatalysis.
Display omitted
•Removal of pollutant in air mixture by photocatalysis and plasma is investigated.•Synergetic effect of ...combined system is explored.•The by-products of each binary mixture were identified and evaluated.•Monitoring of mineralization and ozone has been done at pilot scale.
This paper mainly deals with the isovaleraldehyde degradation with the help of a nonthermal plasma surface discharge (NPSD) coupled with photocatalysis. The efficiency of NPSD reactor, for gas treatment, was studied for different binary mixtures: (1) mixture of aldehydes (Isovaleraldehyde and Butyraldehyde) and (2) mixture of aldehyde and amine (Isovaleraldehyde and Trimethylamine). A planar continuous reactor is used to investigate the effect of addition of another pollutant on the performance of oxidation process.
A synergetic effect was observed by combining NPSD and photocatalysis for the degradation of mixture of pollutants. In addition, combined NPSD/photocatalysis has significantly enhanced the CO2 selectivity, as compared to NPSD alone. This is attributed to the formation of more reactive species due to the presence of TiO2 in the plasma discharge zone. Moreover, ozone and UV light on TiO2, produced by plasma, have activated the surface leading to enhanced mineralization. In addition, the byproducts of each binary mixture were identified and evaluated.
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