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The formation rates and energy yields of H2 and H2O2 from pure water exposed to a nonthermal pulsed plasma-gliding arc reactor equipped with a spray nozzle were determined. Both H2 and H2O2 formation rates were the highest with the argon carrier where the maximum energy yields were 13 and 81 g/kWh, respectively. Both H2O2 and H2 were suppressed with carrier gases (air and nitrogen) where significant amounts of nitrates are formed. The energy yields of H2 and H2O2 with the argon carrier gas in the present work are higher than previously reported microwave plasma, corona, and AC gliding arc. The results for H2 are very close to an ideal quenching limit of 45% of thermodynamic limitations, thereby suggesting that the presence of water droplets in the plasma enhance energy yield through enhanced quenching of radicals and reactions that destroy the desired molecular products.

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Low temperature atmospheric pressure plasma (produced by a 250 mW pulsed gliding arc discharge) with water spray was utilized to inactivate bacteria colonies of Escherichia coli grown on the surface of an agar substrate. The pH, solution conductivity, H2O2, and nitrate concentrations were determined for air and argon carrier gases and different water flow rates. Control experiments conducted by spraying solutions of H2O2 in the absence of the discharge demonstrated that this chemical and its delivery by spraying account for approximately two to three orders of magnitude (depending upon bacterial loading) of the bacterial colony decontamination process for both carrier gases when bacteria are allowed to grow on the agar plate to form a biofilm. Reactive species or other factors arising from the gas flow from the plasma with the water spray caused bacteria inactivation of one to two orders of magnitude beyond those of spraying H2O2 alone.magnified image

The formation rates and energy yields of H2 formed from methanol, propanol, and ethanol solutions exposed to a nonthermal pulsed plasma-gliding arc reactor equipped with a spray nozzle were determined. The H2 energy yield formation was the highest with Ar carrier and pure methanol giving 176 ± 25% kW h at the highest liquid flow rate. This value is higher than other reported plasma technologies and within error of the energy yields for more conventional thermal reforming. Liquid droplets can enhance energy yield; however, the low chemical yields of H2 suggest the need for reactor operation with a recycle stream.

Plasma activated water (PAW) can represent an alternative to chemical fertilizers in agriculture. The effects of PAW treatment applied in two concentrations (1.5 or 3.0 mg L−1 NO3−) on some morphological, physiological, biochemical parameters and yield of Lactuca sativa L. grown in two different pot volumes (400 or 3200 cm3) were investigated in this study. The results showed that both PAW concentrations did not influence the germination, once the process was initiated. Positive effects of the treatments were registered on the length of radicle and hypocotyls of lettuce at a concentration of 1.5 mg L−1 NO3− (PAW I), the chlorophyll content was significantly increased at a concentration of 3.0 mg L−1 NO3− (PAW II) and bigger pot volume, also the foliar weight and area. No significant differences between the treated and untreated plants were recorded for the root weight, leaf length and width. The dry weight was significantly higher for the lettuce treated with PAW I and II grown in big volume pots at 57 days after transplanting (DAT) and small volume pots at 64 DAT. The nitrites content of the lettuce grown in big pots was lower than of the lettuce grown in small pots, regardless of the PAW treatment. Contrary, the nitrates content was higher in the lettuce grown in big pots (up to 36.4 mg KNO3/g DW), compared to small pots (under 0.3 mg KNO3/g DW).

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