Synergistic effect of pulsed corona discharges and ozonation on decolourization of methylene blue in water

Abstract

The effect of O 2 and O 3 bubbling on decolourization of methylene blue by pulsed corona discharges in water was studied. The pulsed corona discharges were produced by charging an 80 pF capacitor with a 40 kV DC source, through a 100 M resistor, and discharging it into a needle-plate type reactor at 60 Hz through a rotating spark gap switch. A 20 ml sample of 13.25 mg l −1 methylene blue in distilled water was decolourized in 120 min.Bubbling O 2 at 10 ml min −1 through the discharge region reduced the decolourization time to 25 min. Bubbling O 2 containing 1500 µmol O 3 l −1 at 10 ml min −1 reduced the decolourization time to 8 min. The O 3 was produced by fractionating input energy between a water treatment reactor and a O 3 generator, i.e. no additional energy was consumed for O 3 production. Under the same experimental conditions methylene blue solution in tap water was decolourized in >210 min by corona discharge in solution, in 30 min by corona discharge with O 2 bubbling, and in 11 min by corona discharge with bubbling of O 2 containing 1500 µmol O 3 l −1 .

Enhanced degradation of organic pollutant 4-chlorophenol in water by non-thermal plasma process with TiO2

“…The gas sources, such as O 2 [5,7,23], air [6,15], N 2 [26], O 3 [2,[9][10][11][12], O 2 /N 2 mixture [27,28] and argon [7,24,28], present in aqueous pulsed discharge plasma process highly affected the formation of the active species and the removal of the organic pollutants, so O 2 , N 2 , and air (atmosphere) in our work were selected as the gas sources to be investigated. The initial experimental conditions were similar to those above optimum experimental conditions, except for gas source.…”

“…Recently, to enhance the degradation efficiency of organic contaminants and energy efficiency of power source, oxidants, such as ozone [2,5,[9][10][11][12], hydrogen peroxide [3,13] were tentatively introduced into pulsed discharge plasma process. Meantime the novel reactors [e.g., hybrid gas-liquid electrical discharge reactor [6,14] or with distinctive electrode configuration (made of porosity reticulated vitreous carbon (RVC) [6] or cylindrical wetted wall reactor using direct contact of gas corona discharge [15]] were designed to form more numerous reactive radicals.…”

Degradation of organic dyes in water by electrical discharges

“…Electrical discharges in water or at the water-gas interface have been investigated as well for the degradation of various organic compounds [2,[9][10][11][12][13][14][15][16][17][18]. Gas phase ozone concentrations up to 3000 ppmv and liquid phase hydrogen peroxide concentrations up to 2.5 mmol/l were reported [19,20].…”

Degradation of Organic Contaminants in Water by Pulsed Corona Discharge

“…(4,5) Recently, advanced oxidation method using pulsed corona discharges combined with ozone has been improved markedly for the remediation of waste water, which results in effective mineralization of aqueous phase wastes. (6,7) However, the efficiency of the mass transfer of gaseous ozone into the aqueous phase was low. An advanced oxidation processes (AOPs) employing pulsed corona discharge combined with hydrogen peroxide has been explored.…”