Dielectric Barrier Discharge Plasma Technology Research Articles

Mechanistic study on 4, 4'-sulfonylbis removal with CO2/Ar gas-liquid DBD plasma

Abstract In this study, a single dielectric barrier discharge (DBD) coaxial reactor was used to degrade 4, 4'-sulfonylbis (TBBPS) in water using greenhouse gas (CO2) and argon as the carrier gases. The investigation focused on CO2 conversion, reactive species formation, gas-liquid mass transfer mechanism, and degradation mechanism of TBBPS during the discharge plasma process. With the decrease of CO2/Ar ratio in the process of plasma discharge, the emission spectrum intensity of Ar, CO2 and excited reactive species was enhanced. This increase promoted collision and dissociation of CO2, resulting in a series of chemical reactions that improved the production of reactive species such as ·OH, 1O2, H2O2 and O3. These reactive species initiated a sequence of reactions with TBBPS. Results indicated that at a gas flow rate of 240 mL/min with a CO2/Ar ratio of 1:5, both the highest CO2 conversion rate (17.76%) and TBBPS degradation rate (94.24%) were achieved. The degradation mechanism was elucidated by determining types and contents of reactive species present in treatment liquid along with analysis of intermediate products using liquid chromatography-mass spectrometry techniques. This research provides novel insights into carbon dioxide utilization and water pollution control through dielectric barrier discharge plasma technology.

Degradation performance and mechanism of microcystins in aquaculture water using low-temperature plasma technology

The eutrophication of aquaculture water bodies seriously restricts the healthy development of the aquaculture industry. Among them, microcystins are particularly harmful. Therefore, the development of technologies for degrading microcystins is of great significance for maintaining the healthy development of the aquaculture industry. The feasibility and mechanism of removing microcystins-LR by dielectric barrier discharge (DBD) plasma were studied. DBD discharge power of 49.6 W and a treatment time of 40 min were selected as the more suitable DBD parameters, resulting in microcystin-LR removal efficiency of 90.4%. Meanwhile, the effects of initial microcystin-LR concentration, initial pH value, turbidity, anions on the degradation effect of microcystin-LR were investigated. The removal efficiency of microcystin-LR decreased with the increase of initial microcystin-LR concentration and turbidity. The degradation efficiency of microcystin-LR at pH 4.5 and 6.5 is significantly higher than that at pH 8.5 and 3.5. HCO3− can inhibit the removal efficiency of microcystin-LR. Furthermore, five intermediates products (m/z = 1029.5, 835.3, 829.3, 815.4, 642.1) were identified in this study, and the toxicity analysis of these degradation intermediates indicated that DBD treatment can reduce the toxicity of microcystin-LR. e－aq, •OH, H2O2, and O3 have been shown to play a major role in the degradation of microcystin-LR, and the contribution ranking of these active species is e－aq > •OH > H2O2 > O3. The application of DBD plasma technology in microcystin-LR removal and detoxification has certain development potential.

Feasibility and mechanism of removing Microcystis aeruginosa and degrading microcystin-LR by dielectric barrier discharge plasma

Harmful cyanobacterial bloom is one of the serious environmental problems worldwide. Microcystis aeruginosa is a representative harmful alga in cyanobacteria bloom. It is of great significance to develop new technologies for the removal of Microcystis aeruginosa and microcystins. The feasibility and mechanism of removing microcystis aeruginosa and degrading microcystins by dielectric barrier discharge (DBD) plasma were studied. The suitable DBD parameters obtained in this study are DBD (41.5 W, 40 min) and DBD (41.5 W, 50 min), resulting in algae removal efficiency of 77.4% and 80.4%, respectively; scanning electron microscope and LIVE-DEATH analysis demonstrate that DBD treatment can disrupt cell structure and lead to cell death; analysis of elemental composition and chemical state indicated that there are traces of oxidation of organic nitrogen and organic carbon in microcystis aeruginosa; further intracellular ROS concentration and antioxidant enzyme activity analysis confirm that DBD damage microcystis aeruginosa through oxidation. Meanwhile, DBD can effectively degrade the microcystin-LR released after cell lysis, the extracellular microcystin-LR concentration in the DBD (41.5 W) group decreased by 88.7% at 60 min compared to the highest concentration at 20 min; further toxicity analysis of degradation intermediates indicated that DBD can reduce the toxicity of microcystin-LR. The contribution of active substances to the inactivation of microcystis aeruginosa is eaq− >•OH > H2O2 > O3 > 1O2 >•O2− >ONOO−, while on the degradation of microcystin-LR is eaq− >•OH > H2O2 > O3 >•O2− >1O2 > ONOO−. The application of DBD plasma technology in microcystis aeruginosa algae removal and detoxification has certain prospects for promotion and application.

Experimental study on the effect of H2O and O2 on the degradation of SF6 by pulsed dielectric barrier discharge

SF6 has excellent insulation performance and arc extinguishing ability, and is widely used in the power industry. However, its global warming potential is about 23,500 times that of CO2, it can exist stably in the atmosphere, it is not easily degradable and is of great potential harm to the environment. Based on pulsed dielectric barrier discharge plasma technology, the effects of H2O and O2 on the degradation of SF6 were studied. Studies have shown that H2O can effectively promote the decomposition of SF6 and improve its degradation rate and energy efficiency of degradation. Under the action of a pulse input voltage and input frequency of 15 kV and 15 kHz, respectively, when H2O is added alone the effect of 1% H2O is the best, and the rate and energy efficiency of degradation of SF6 reach their maximum values, which are 91.9% and 8.25 g kWh−1, respectively. The synergistic effect of H2O and O2 on the degradation of SF6 was similar to that of H2O. When the concentration of H2O and O2 was 1%, the system obtained the best rate and energy efficiency of degradation, namely 89.7% and 8.05 g kWh−1, respectively. At the same time, different external gases exhibit different capabilities to regulate decomposition products. The addition of H2O can effectively improve the selectivity of SO2. Under the synergistic effect of H2O and O2, with increase in O2 concentration the degradation products gradually transformed into SO2F2. From the perspective of harmless treatment of the degradation products of SF6, the addition of O2 during the SF6 degradation process should be avoided.

Research progress and the prospect of CO2 hydrogenation with dielectric barrier discharge plasma technology

Research progress and the prospect of CO2 hydrogenation with dielectric barrier discharge plasma technology

Green Chemistry Applied to Ground Coffee Volatile Compounds Modification Aiming Coffee Aroma Improvement

Aroma has a major role in coffee acceptance by consumers. This work has assessed the application of cold plasma technology to induce modifications in ground coffee beans without resorting to solvents or additives, thus applying a green chemistry approach. Cold plasma improved and modulated coffee aroma, increasing desirable and decreasing undesirable aroma notes. Ground coffee beans were subjected to dielectric-barrier discharge (DBD) plasma at different excitation frequencies. Its volatile chemical profile was determined by GC-MS. The odor activity value technique was used to evaluate the aroma profile. Extensive chemical changes occurred with aldehydes, furans, and pyrazine compounds. This work showed that setting proper excitation frequency enables modulating changes toward oxidation and C-C bond scission. Chemical reaction pathways were postulated and discussed. DBD plasma technology enhanced the importance of the desirable cocoa note from 74.4 to 88.6% and decreased the significance of the green and fruity notes from 8.5 to 3.2% and 2.7 to 1.9%, respectively. Plasma-induced reactions can help mitigating aroma defects.

Synthesis of Fe3O4/CuO/ZnO/RGO and its catalytic degradation of dye wastewater using dielectric barrier discharge plasma

The design of an efficient and green dye degradation technology is of great significance to mitigate water pollution as well as ecological damage. Fe3O4/CuO/ZnO/RGO was prepared by solvothermal synthesis and homogeneous precipitation. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), and vibrating-sample magnetometry (VSM) were used to characterize the samples, to explore the morphology and structural composition of the composites. To enhance the degradation efficiency, a dielectric barrier discharge (DBD)–Fe3O4/CuO/ZnO/RGO co-catalytic system was created based on the DBD plasma technology. Response surface methodology analysis results demonstrate that the degradation effect of DBD–Fe3O4/CuO/ZnO/RGO is optimal and the decolorization rate is 95.06 % when the solution pH is 3, conductivity is 0.5 mS/cm, the input voltage is 90 V, and Fe3O4/CuO/ZnO/RGO concentration is 0.18 g/L. Therefore, this study offers a novel method for dye degradation and confirms the viability of a DBD–Fe3O4/CuO/ZnO/RGO synergistic catalytic system.

Influence of Dielectric Barrier Discharge Cold Plasma Treatment on Starch, Gelatin, and Bacterial Cellulose Biodegradable Polymeric Films

The environmental damage caused by plastic packaging and the need to reduce pollution requires actions to substitute plastic materials for more sustainable and biodegradable materials. Starch, gelatin, and bacterial cellulose films are three potential biodegradable polymeric films for use in packaging. However, these materials need improvements in their physical, chemical, and mechanical properties to be used in packaging. In this work, these films were treated with cold plasma to evaluate the effects of treatment conditions on several physical, chemical, and mechanical properties. The dielectric barrier discharge plasma technology was applied with varying treatment times (0 to 20 min) and excitation frequencies (50 to 900 Hz) at 20 kV. The optimal excitation frequency for starch films (50 Hz) was different from the optimal frequency for gelatin and bacterial cellulose films (900 Hz), indicating a high dependency on the treatment in this variable that is often neglected. Plasma treatment improved the hydrophobicity, surface morphology, water resistance, and mechanical properties of all three films, with the advantage of not recurring to chemical or biological additives.

Changing Ready-to-Drink Coffee Aroma Using Dielectric Barrier Discharge Plasma

Coffee is one of the world’s most consumed beverages, and its aroma plays an essential role in consumer acceptance. Ready-to-drink coffee is popular in many countries and can be bought with different flavoring agents. In this work, we evaluated the changes that can be made to ready-to-drink coffee by applying cold plasma to convert coffee volatiles, modulating its aroma chemically. To achieve this goal, dielectric-barrier discharge (DBD) plasma was applied to ready-to-drink coffee at different excitation frequencies and processing times. Several chemical reactions were observed, and their routes were proposed. DBD plasma technology increased the relevance of the desirable nutty descriptor from 2.9 to 27.7%. The technology can also increase the significance of the fruity and green descriptors, which can be modulated to produce specialty or gourmet ready-to-drink coffees.

Inactivation kinetics of polyphenol oxidase and peroxidase in pineapple juice by dielectric barrier discharge plasma technology

The non-thermal plasma technique is an innovative non-thermal approach for food preservation and decontamination. Polyphenol oxidase (PPO) and peroxidase (POD), the principal food degrading enzymes in pineapple juice, were inactivated by the Dielectric Barrier Discharge (DBD) plasma. The inactivation kinetics of PPO and POD in pineapple juice were examined at three different voltages 25, 35, and 45 kV for up to 10 min of plasma treatment. The present study's findings revealed that plasma parameters such as voltage and treatment time substantially reduced enzyme activity of both enzymes, with the former parameter having a more pronounced influence on enzyme inactivity. To mathematically represent the model parameters, established kinetic models viz. log-linear, Weibull, and logistic were fitted to observe experimental data. The Weibull model was discovered to be the best fit for the enzyme inactivation kinetics. The scale factor for PPO was 15.95, 10.87, and 5.73 min at 25, 35, and 45 kV, respectively which was lower than POD with scale factor 40.74, 19.76, and 7.28, respectively. This shows that POD was more resistant to inactivation by DBD plasma than PPO.

Mechanism of dielectric barrier discharge plasma technology to improve the quantity of short-chain fatty acids in anaerobic fermentation of waste active sludge.

The mechanism of improving the anaerobic fermentation performance of waste active sludge by using dielectric barrier discharge (DBD) plasma pretreatment technology was investigated. The maximum accumulation of short-chain fatty acids (SCFAs) was observed on the 7th day of anaerobic fermentation when the DBD power was 76.50 W, which was 1726.70 mg COD/L, 1.50 times of the control group. The ratio of acetic acid in DBD group was 9.30% higher than that in the control. Further mechanism research indicated that DBD pretreatment can destroy the structure of extracellular polymer substances and release organic substances such as protein and polysaccharide. The dissolved organic matter analysis indicated that the DBD technique could increase the release of biodegradable organics (eg., tyrosine proteins, soluble microbial by-products), thus accelerate the biotransformation of organic substance. Bacterial community structure analysis showed that the increase in the abundance of Firmicutes and Bacteroidetes and the decrease in the abundance of Proteobacteria in DBD group were beneficial to the accumulation of SCFAs. Besides, further archaeal analysis indicated that the decrease of Methanosaeta sp. and Methanosarcina sp. abundance in the DBD group facilitate acetic acid accumulation. This study demonstrated that the DBD technique can be used as an effective and potential pretreatment method to improve sludge anaerobic fermentation performance.

Study of detoxification of methyl parathion by dielectric barrier discharge (DBD) non-thermal plasma at gas-liquid interface：mechanism and bio-toxicity evaluation

Methyl parathion (MP) as an organophosphorus pesticide has been used in the control of agricultural pests and diseases. Due to its high toxicity and persistence in the environment, MP may pose threat to human health when it is released into environmental water. For MP treatment, people have found that oxidative degradation of MP may generate some intermediates which are more toxic than MP itself, such as methyl paraoxon. Herein, we proposed a new method of applying dielectric barrier discharge (DBD) non-thermal plasma technology to treat MP in aqueous solution, and investigated the influences of different gases, pH value, discharge voltage/power, and main active species on the MP removal efficiency. In particular, the safety of DBD treatment was concerned with analysis of the biological toxicity of the byproducts from the DBD oxidation, and the DBD-induced degradation together with the involved mechanism was explored therein. The results showed that the production of toxic intermediates could be effectively suppressed or avoided under certain treatment conditions. As such, this work demonstrates that the proper application of DBD plasma technology with necessary caution can detoxify methyl parathion effectively, and also provides a practical guide for low-temperature plasma application in treatment of various organophosphorus pesticides in agricultural wastewater.

Comparative study of two cold plasma technologies on apple juice antioxidant capacity, phenolic contents, and enzymatic activity

Cold plasma technologies are being developed as an alternative to thermal processes aiming toward preservation while retaining or improving several quality parameters. This research evaluates the use of dielectric barrier discharge (DBD) plasma and glow discharge plasma on browning enzyme activity, antioxidant capacity, and total phenolic content of apple juice. This work evaluated the effects of the main DBD plasma operating conditions, such as excitation frequencies (50–900 Hz), and glow plasma discharge operating conditions, such as air plasma flow rates (10–30 ml/min) and processing time (10–30 min). Both plasma systems partially inactivated the enzymes polyphenol oxidase and peroxidase and consequently increased apple juice's total phenolic content and antioxidant activity. DBD plasma technology presented better efficacy in increasing apple juice's total phenolic content and antioxidant capacity. DBD plasma and glow discharge plasma have the same effectiveness in inactivating browning enzymes in apple juice. Novelty impact statement This work compares two cold plasma technologies for apple juice processing. The results showed that different plasma technologies lead to different outcomes and that the right choice of technology should be made for a given goal.

Catalysis of MnO2-cellulose acetate composite films in DBD plasma system and sulfamethoxazole degradation by the synergistic effect

Herein, dielectric barrier discharge (DBD) plasma and MnO2-cellulose acetate (MnO2/CA) composite films was coupled together to degrade sulfamethoxazole (SMX) in water. The MnO2/CA composite films were firstly prepared successfully though heating blending method in this study and then characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectra, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TG). Catalytic effect of the MnO2/CA films was investigated by comparing the removal percentages, the kinetic constants, the energy utilization efficiencies (G50) as well as the COD and TOC removal during the SMX degradation in the DBD plasma system with or without the MnO2/CA films addition under different reaction conditions. The optimal catalytic performance was obtained by adding the 3% MnO2/CA films into the DBD plasma system and the alkaline solution condition was favorable for the SMX degradation. After four times using, the MnO2/CA composite films still maintained the catalytic activity. Catalytic mechanism of the MnO2/CA films was speculated by analyzing the changes of solution pH and conductivity during the reaction, concentrations of the formed O3 and H2O2 in water and the generated active species (1O2 and ·OH) in both the DBD plasma system and the DBD-MnO2/CA films system. The quenching test was also carried out to figure out the important effect of the ·O2−, 1O2 and ·OH for the SMX degradation in the synergistic system. Finally, LC-MS was used to analyze the main intermediates generated during the SMX degradation and the possible degradation pathways were accordingly speculated. The research could provide a new direction for the development and application of the DBD plasma technology as well we the composite films catalyst.

Inhibitory effects of atmospheric dielectric barrier discharge plasma against Bacillus cereus and Staphylococcus aureus on Gwamegi (semi-dried Cololabis saira)

The current study was conducted to investigate the effects of atmospheric dielectric barrier discharge (DBD) plasma on the reduction of B. cereus and S. aureus, both potential hazardous bacteria on Gwamegi. DBD plasma devices (1.1kV, 43kHz, 5-60min, N2 : 1.5lpm for 5, 10, 20, 30 and 60min) were used to investigate the reduction effect. In the B. cereus by DBD plasma treatment, the 5-60min indicated a reduction of 0.2-1.2 log CFU/g. The reductions of S. aureus at the same duration time of DBD plasma were 0.1-1.1log CFU/g. The D-values for B. cereus and S. aureus were 49.0 (R2 =0.98) and 61.0 (R2 =0.94) min, respectively. The pH values for 0-30min (6.00-6.01) were not significantly different, but significant differences at 60min (6.09). There were no significant sensorial differences in colour (6.4-5.2) and flavour (6.2-5.3), but showing significant differences in appearance (6.6-5.2), texture (6.3-5.1) and overall acceptability (6.5-5.5). This study indicates that the 60min of DBD plasma treatment resulted in >1log CFU/g of B. cereus and S. aureus without concomitant adverse changes in pH and most sensory properties in semi-dried Gwamegi. This novel DBD plasma technology can be applied in semi-dried food production and distribution processes to enhance dried fishery food hygiene and safety.

Research on methylene blue degradation based on multineedle-to-plane liquid dielectric barrier discharge mode

Advanced oxidation processes (AOPs) focusing on non-thermal plasma induced by dielectric barrier discharge (DBD) are adequate sources of diverse reactive oxygen species beneficial for water and wastewater treatment. The degradation of methylene blue (MB) was investigated using plasma liquid dielectric barrier discharge with a multineedle-to-plane reactor. MB at 20 mg/L concentration was almost completely degraded after 40 min of treatment. In this study, several important parameters, such as input voltage, initial concentration, initial pH, discharge gap, tip radius of curvature, and presence of radical, were evaluated, and their effects on MB degradation rate were investigated. The degradation rate of MB increased with initial pH. By contrast, the degradation rate showed a downward trend with increasing initial concentration, discharge distance, and tip curvature radius. O3 and H2O2 produced during the degradation process considerably influenced the entire degradation process, especially when the quenching agents of HO⋅, O2·- and e− were added, and the degradation efficiency was obviously reduced. According to the measured spectrum, the possible process of the discharge process was analyzed, and the COMSOL finite element simulation is performed to obtain the visualization of the discharge model. This work can provide exploratory platforms for comprehensively understanding and enhancing MB degradation in DBD plasma technology.

Insights into water film DBD plasma driven by pulse power for ibuprofen elimination in water: performance, mechanism and degradation route

• IBP elimination using water film DBD plasma by pulse power was investigated. • The impact of various parameters on IBP elimination was inspected. • OH, electron, 1 O 2 and · O 2 – participation in IBP decomposition. • The degradation route was proposed based on DFT calculation and LC-MS. • The toxicity of actual wastewater alleviated after water film DBD treatment. Development of efficient abatement technology for drugs and personal care products (PPCPs) has important scientific and practical significance to restrain its discharge to the natural water environment. This research aims to investigate ibuprofen (IBP) elimination in water film dielectric barrier discharge (DBD) plasma system driven by pulse power. With raising input power, the removal rate was improved. When input was 95 W, the removal rate and kinetic constant were up to 96.1% and 0.090 min −1 , respectively. Besides, heightening frequency, duty ratio and solution flowrate would promote the degradation of IBP. IBP were more favorably degraded at lower IBP concentration and neutral pH condition. Active species including ·OH, electron, 1 O 2 and · O 2 – dominated decomposition of IBP. The generation of O 3 , · OH and H 2 O 2 in deionized water and IBP solution was compared. UV–Vis spectrum and three dimensional fluorescence spectroscopy illustrated that IBP molecules could be decomposed effectively after DBD plasma treatment. During IBP degradation, COD and TOC was also relieved with extension of treatment time. The possible degradation routes of IBP in water film DBD plasma system were proposed based on LC-MS and Discrete Fourier transform (DFT) simulation. Based on the identified intermediates, their potential toxicity was evaluated with the help of US-EPA-TEST software. Water film DBD plasma technology was also suitable for actual wastewater treatment. The comparison of other technologies for IBP degradation was carried out finally. This work can provide exploratory platforms for comprehensively understanding and enhancing IBP degradation in DBD plasma technology.

Preparing potato starch nanocrystals assisted by dielectric barrier discharge plasma and its multiscale structure, physicochemical and rheological properties

Non-thermal plasma has increasingly been used for surface modification of various materials as a novel green technology. In this study, we prepared potato starch nanocrystals (SNCs) assisted by dielectric barrier discharge plasma technology and investigated its multiscale structure, physicochemical properties and rheology. Plasma treatment did not change the morphology and crystalline pattern of SNCs but reduced the crystallinity. The amylose content, swelling power, gelatinization temperature, and apparent viscosity of SNCs decreased after the plasma process by depolymerizing the amylopectin branch chains and degrading SNCs molecules. Besides, plasma increased the rapidly digestible starch and resistant starch content. Changes in rheological properties of plasma treated SNCs suggested that the plasma process increased the flowing capacity. The effective structural and functional changes of plasma treated SNCs confirm that plasma technology has great potential for modification of SNCs.

Antioxidant Effects of Anthocyanin-Rich Riceberry™ Rice Flour Prepared Using Dielectric Barrier Discharge Plasma Technology on Iron-Induced Oxidative Stress in Mice.

Redox-active iron generates reactive oxygen species that can cause oxidative organ dysfunction. Thus, the anti-oxidative systems in the body and certain dietary antioxidants, such as anthocyanins, are needed to control oxidative stress. We aimed to investigate the effects of dielectric barrier discharge (DBD) plasma technology in the preparation of Riceberry™ rice flour (PRBF) on iron-induced oxidative stress in mice. PRBF using plasma technology was rich in anthocyanins, mainly cyanidine-3-glucoside and peonidine-3-glucoside. PRBF (5 mg AE/mg) lowered WBC numbers in iron dextran (FeDex)-loaded mice and served as evidence of the reversal of erythrocyte superoxide dismutase activity, plasma total antioxidant capacity, and plasma and liver thiobarbituric acid-reactive substances in the loading mice. Consequently, the PRBF treatment was observed to be more effective than NAC treatment. PRBF would be a powerful supplementary and therapeutic antioxidant product that is understood to be more potent than NAC in ameliorating the effects of iron-induced oxidative stress.

Synergistic photocatalytic activity of a combination of carbon nanotubes-graphene-nickel foam nanocomposites enhanced by dielectric barrier discharge plasma technology for water purification.

Degradation activity of plasma catalysis between dielectric barrier discharge (DBD) and carbon nanotubes-graphene-nickel foam (CNTs-G-Nif) has been studied in treatment of dye wastewater. CNTs-G-Nif was prepared through a two-step chemical vapor deposition (CVD) approach. The composite has been characterized by different techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectroscopy. SEM results showed that the Nif as the growth substrate was evenly wrapped by G and then CNTs were successfully grown on G as the support. The growth mechanism of composite was proposed. The possible coupled catalytic mechanism between DBD and CNTs-G-Nif were addressed. In addition, the modification on G-Nif was found by SEM during the discharge process in liquid phase. And the modification mechanism of DBD plasma (DBDP) acting on composites was discussed. Finally, by means of analyses of ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), the general degradation pathway and stepwise degradation pathways of alizarin green (AG) were proposed in detail.