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Eliminating dye pollutants from water systems is essential to prevent long-term environmental damage, as these substances can hinder photosynthesis, reduce water quality, and introduce harmful chemicals into aquatic ecosystems. This study explores the potential of non-thermal plasma technology, specifically the Dielectric Barrier Discharge configuration, for the degradation of Methylene Blue dye in aqueous solutions. A systematic investigation was conducted to assess the influence of key operational parameters such as applied voltage, initial Methylene Blue concentration, treatment time, and pH on the removal efficiency of Methylene Blue. Using Response Surface Methodology in conjunction with Design Expert software, optimal conditions were identified, including a voltage of 15 kV, a Methylene Blue concentration of 20 mg/L, a treatment time of 42.6 min, and a pH of 9, achieving a removal efficiency of 67.54%. Additionally, under specific condition, a maximum RE of 91.7% was achieved. The study demonstrates the efficacy of the cold plasma process in efficiently degrading Methylene Blue dye, offering a scalable and environmentally friendly solution for treating dye-laden wastewater in industrial applications. [ABSTRACT FROM AUTHOR]

We propose a scheme for dynamically controlling the geometric configurations of honeycomb superlattice plasma photonic crystals (HsPPCs) in dielectric barrier discharge. A rapid transition from a simple honeycomb lattice to diverse HsPPCs has been achieved in ambient air. The HsPPCs exhibit substantial omnidirectional band gaps (OBGs), approximately three times larger than those of simple honeycomb lattices. An experimental verification of the OBGs as well as their frequency shifting with reconfiguration of different HsPPCs has been provided. A phenomenological reaction-diffusion system is developed to unravel the generation mechanism of HsPPCs. The experimental observations are consistent with the numerical simulations. Our approach provides a unique method for manufacturing tunable HsPPCs which significantly enhance the band gap size and improve the photonic properties. [ABSTRACT FROM AUTHOR]

Adapting green technologies to the leather industry plays a crucial role in environmental protection by reducing wastewater load, using fewer chemicals, minimizing waste, saving energy and water, reducing costs, and increasing productivity. Plasma treatment, accepted as a clean technology, is mostly used in textiles compared to limited studies in leather. Thus, this study will be the first in this respect. Crust leathers, treated with air and argon atmospheric plasma under the conditions of 130 W, 100 s, were dyed with acid and metal complex dyestuffs for 45 minutes at 20°C in different concentrations (1%–4%), and investigated in terms of dyeing properties, wastewater load, and the characterization of the leathers in terms of surface, mechanical and antimicrobial properties. The K/S results of 2% dyeing obtained after air and argon plasma treatment gave similar values with the untreated leathers dyed with a concentration of 4%. This result revealed that half amount of dyestuff is sufficient for the dyeing process to obtain the same dyeing characteristics with the maximum concentration of dyestuff (4%). In addition to improved dyeing efficacy, a reduction up to 35% in chemical oxygen demand value was achieved in addition to 2 and 3 mm inhibition zones without any negative effect to tensile and tear strength of leathers. Consequently, atmospheric plasma treatment is found to be effective and comprising as environment-friendly, and sustainable technique for the leather industry in terms of reduced dyestuff amount and wastewater load without altering the characteristics of the leathers. [ABSTRACT FROM AUTHOR]

The purpose of the paper is to convert coal-water-oil slurry (CWOS) into an alternative fuel (AF) for internal combustion engines by high-voltage discharge (HVD) and dielectric barrier discharge (DBD) plasmas. The CWOS is prepared through adding oil to coal-water mixture in a relevant ratio. And the CWOS was converted to AF by passing through high-voltage discharge and DBD plasma with gas emission and liquefaction reactions. It is found that after HVD and DBD plasma treatments, the CWOS has the average coal size reduced from 12.95 to 8.26μm, improved dispersibility, less deposits, and calorific value enhanced by 35%. The effects of some parameters are analyzed on the conversion of CWOS to AF, and the AF is characterized. The plasma-treated CWOS is similar to other liquid fuels in rheological property and calorific value. It is therefore concluded that it can be directly employed to internal combustion engines with a little design modification. The suggested method can be an alternative way of converting CWOS to AF without any dispersant and stabilizer. [ABSTRACT FROM AUTHOR]

Occurrence of acetaminophen in wastewater and surface waters is a worldwide concern. This study analyzes the application of a dielectric barrier discharge reactor for non-thermal plasma generated in Ar–O2 mixtures on a thin film of acetaminophen aqueous solution in order for this pharmaceutical compound to be oxidized. Solution samples collected during the process were analyzed with gas chromatography mass spectrometry technique. At the end of the process, the treated solution was filtered with a Solid Phase Extraction cartridge, and the by-products were recovered with methanol ACS and analyzed immediately. It can be seen from the results obtained that, firstly, the degradation efficiency largely dependents on the operating parameters; secondly, degradation efficiencies of up to 97% were obtained when O2 reached 20% in the gas phase; and finally, hydroquinone, acetamide and other aromatic products were identified as degradation by-products. The nature of the by-products detected indicates that the acetaminophen oxidation pathway occurred through •OH radical reaction instead of the direct O3 reaction. [ABSTRACT FROM AUTHOR]

Plasma–liquid reactions represent an emerging green chemical process for nitrogen fixation; however, these processes generally exhibit low selectivity for ammonium (NH4+). This limitation highlights the need to explore simple methods to increase NH4+; selectivity. In this study, a catalyst-free falling film dielectric barrier discharge plasma system was employed for the selective synthesis of NH4+. By manipulating the flow state of the discharge gas, NH4+ selectivity was found to increase by 138.4% in the sealed gas flow state compared to the flowing gas state. Furthermore, an increase in the discharge voltage positively influenced the NH4+ selectivity. This phenomenon can be attributed to higher energy input and longer reaction times, which facilitate the formation of nitrogen molecular ions, a critical intermediate in ammonia synthesis. The reaction products were analyzed by UV spectrophotometry and emission spectroscopy to investigate the underlying mechanisms of ammonia synthesis. This study reveals the highest reaction rate reported to date for ammonia synthesis via single-system plasma gas–liquid reactions and offers a novel way to improve both the yield and selectivity of ammonium synthesis via non-thermal plasma gas–liquid interactions. [ABSTRACT FROM AUTHOR]

In this work, a method for maximizing the efficacy of ozone production by dielectric barrier discharge (DBD) is presented. By developing an optimiser-based hardware-in-the-loop system, the effects of varying input waveform parameters and the flowrate of the input gas on the reactor conditions could be explored with greater fidelity than in previous literature. The waveform used is biharmonic, consisting of the sum of two sine waves and allowing a greater number of explorable parameters. The performance of the reactor, evaluated using the parametric sweep technique, is compared to that of a hybrid optimiser combining particle swarm optimisation and pattern search. Two metrics were targeted: ozone concentration-to-power ratio (ppm/W) and ozone quantity for a given energy (g/kWh). Thus, the characteristics of the input voltage waveform and flowrate were adjusted to target high ozone generation efficacy for the reactor used in the experiment. Results show that the optimiser achieves 343 ppm/W compared to 170 ppm/W for the parametric sweep, using a similar number of measurements. [ABSTRACT FROM AUTHOR]