Spectrochemical Analysis of Ozone Density for Pulsed Plasma Discharge in Oxygen–Water Mixture

Oxidizing species generated during the plasma discharges in gas–water mixture are well reported for their potential applications in water disinfection. Ozone is an important oxidizing agent produced in these non-thermal plasmas. Present paper reports the spectrochemical analysis of ozone generated during pulsed plasma discharge in oxygen–water mixture. Ozone density in the plasma discharge channel was estimated by using absorption of incident ultraviolet radiation of a light emitting diode at 253.6 nm in the Hartley band of ozone. Based on UV absorption, the peak ozone density noted in the discharge channel was $$(1.764 \pm 0.11) \times {10}^{16}/{\text{cm}}^{3}$$ . While the post plasma ozone density in the effluent water samples was determined through indigo method. The peak ozone density obtained by using this chemical probe was $$(1.209 \pm 0.052) \times {10}^{16}/{\text{cm}}^{3}$$ , showing post plasma ozone depletion along the water flow. Moreover, ozone concentration was highly influenced by average discharge power and gas temperature and showed a decreasing trend with increase in these parameters. Presently, plasma discharge was also generated in aqueous solution of indigo trisulfonate and the resultant decolorization of known concentration of this dye was used to estimate the density of different oxidants in the discharge channel. Results showed that the estimated peak oxidant density in the discharge channel was $$(3.818 \pm 0.087) \times 1{0}^{16}/{\text{cm}}^{3}$$ . While the energy yield of the plasma discharge for decolorization of indigo trisulfonate was $$(148.905 \pm 16.314)\text{ g}/\text{kWh}$$ with indigo decolorization efficiency of 79.261 ± 1.842%.