Optical characterization of non-thermal plasma jet energy carriers for effective catalytic processing of industrial wastewaters

Abstract

An argon plasma jet was sustained in open air and characterized for its chemical composition. The optically characterized plasma jet was used to treat industrial wastewater containing mixed textile dyes and heavy metals. Since plasma jet produces UV-radiations, the photocatalytic TiO2 was used to enhance plasma treatment efficiency especially for degradation of dyes. Mixed anatase and rutile phases of TiO2 (5.2–8.5 nm) were produced through surfactant assisted sol–gel approach. The emission spectrum confirmed the presence of excited argon, OH, excited nitrogen, excited oxygen, ozone and nitric oxide in the plasma jet. The spectral lines of excited Ar, NO, O3, OH−, N2, $${\mathrm{N}}_{2}^{+}$$ N 2 + , O, $${\mathrm{O}}_{2}^{+}$$ O 2 + and O+ species were observed at wavelength of 695–740 nm, 254.3 nm, 307.9 nm, 302–310 nm, 330–380 nm, 390–415 nm, 715.6 nm, 500–600 nm and 400–500 nm. These reactive species decompose the organic pollutants and separate the heavy metals from the water samples. The conductivity of plasma exposed water samples increased while pH and hardness decreased. The atomic absorption spectrophotometry analysis confirmed the presence of heavy metals in the samples, which were effectively removed through plasma treatment. Finally, the effect of plasma treatment on Staphylococcus aureus strains was more pronounced than Escherichia coli strains.

Dielectric barrier plasma effect on surface functionality and coating properties of ultrasonically coated cotton with ZnO nanoparticles and Aloe vera extraction

“…The efficiency of chemical processes, involved in DBD discharge, is determined by their cross sections for electron collisions and the decreased field. The emission spectrum of DBD revealed the formation of OH − , N 2 , O, O 3 , NO, N + 2 , O + 2 and O + radicals (Naz et al 2021). A peak at 452 was also detected for CO due to splitting of CO 2 into oxygen and CO.…”

Concurrent Synthesis and Immobilization of Ag Nanoparticles over TiO2 via Plasma Reduction for Photocatalytic Treatment of Methyl Blue in Water

“…It was observed that the pH of the solution had a significant impact on the photocatalytic degradation of pollutants. To check the role of pH in dye degradation, tests were conducted with different pH values (3)(4)(5)(6)(7)(8)(9)(10)(11) in 1.0 g/L of Ag/TiO 2 and a 3 mM H 2 O 2 oxidant dose. The dye concentrations were 5 ppm, 10 ppm, and 15 ppm.…”

“…Among these, nanosized TiO 2 is the most frequently used photocatalyst due to its non-toxic nature, low-cost, high surface adsorption affinity, and distinctive chemical, physical, and optical properties. However, these benefits are only manifested when TiO 2 is applied under the ultraviolet region of the light spectrum, especially for photocatalytic dye degradation applications [5]. TiO 2 is only active under UV radiation due to its high band gap (3.2-3.3 eV), which accounts for just 5% of the solar spectrum, while visible light accounts for 45% of solar spectrum [6].…”

Plasma-assisted synthesis of noble nanoparticles coated with hyaluronan: chemico-physical characterization and safety assessment

“…Here we propose the use of atmospheric plasma as an environmentally sustainable, low energy consumption, affordable and highly efficient method to produce size-controlled and safe noble nanoparticles, which did not absorb toxic chemicals on their surface during the synthesis reaction [15][16][17][18][19]. Cold plasma obtained at atmospheric pressure and room temperature results as being rich with energetic electrons that are capable of dissociating, exciting and ionizing gas molecules [20][21][22]. Typical reactions include the formation of a…”