Dielectric barrier discharge in water solution treatment

Application of coaxial dielectric barrier discharge (DBD) reactor for treatment of different water solutions was studied. In this reactor the circulating liquid is a part of discharge electrode configuration. Thus liquid is directly exposed to UV radiation and reactive species like ozone, radicals, ions and electrons. This configuration of DBD also offers to operate the plasma with and without water falling film at one of the electrodes. Thus it can act as a plasma reactor for gas treatment and as a scrubber for soluble compounds in a gas phase, simultaneously. Here we present measurement of hydroxyl radical ("OH) in plasma treated distilled water as well as treatment of phenols, textile dyes, medicaments, herbicides and detergents

Decolorization of reactive black 5 using dielectric barrier discharge in the presence of inorganic salts

Inorganic salts improve the coloration of textiles, which increase pollution load on dyehouse effluent in general. Decolorization of reactive textile dye C.I. Reactive Black 5 was studied using Advanced Oxidation Processes (AOPs) in a non-thermal plasma reactor, based on coaxial water falling film Dielectric Barrier Discharge (DBD). Initial dye concentration in the solution was 40.0 mg L-1. The effects of addition of inorganic salt different high concentrations (NaCl, Na2SO4 and Na2CO3) on the degree of decolorization were studied. Recirculation of dye solution through the DBD reactor with applied energy density 45-315 kJ L-1 was used. The influence of residence time was investigated after 5 minutes and 24 hours of plasma treatment. Decolorization of the dyes was monitored by spectrophotometric measurement. Changes of pH values and the conductivity of dye solution after each recirculation were tested. The most effective decolorization of over 90% was obtained with the addition of NaCl (50 g L-1), applied energy density of 135 kJ L-1 and after residence time of 24 hours of plasma treatment. Decolorization of solutions containing inorganic salts Na2SO4 and Na2CO3 were lower than for the solution without salt

The effect of power on the degradation of propranolol by nonthermal plasma reactor

Propranolol (PRO) is a beta-blocker that is readily detected in surface water and hospital wastewater. This pharmaceutical poses a danger for aquatic animals because it is commonly prescribed for heart diseases and anxiety issues. Advanced oxidation processes are commonly tested for the decomposition of pharmaceuticals because they produce various reactive species at room conditions. A liquid-falling film dielectric barrier discharge (DBD) reactor was used for the treatment of a PRO solution, with no catalysts added. A coaxial construction, accompanied by a peristaltic pump, enables the recirculation of the treated liquid. Ambient air was selected as a feed-gas for nonthermal plasma generation under three levels of power dissipated in plasma. Direct contact of liquid film with plasma in this coaxial reactor enables the efficient transfer of reactive oxygen and nitrogen species generated in plasma to the liquid phase. The degradation rate of PRO, pH value, and conductivity were monitored after every cycle of treatment of PRO solution (100 mg/dm3), and in the presence of scavengers (t-butanol and p-benzoquinone). The PRO concentration was monitored by HPLC-DAD, at 213 nm. As expected, the highest applied power (60 W) contributed to the highest degradation rate (100%). At the same time, in these extreme conditions, pH values dropped from 6 to 2.5 and conductivity increased from 20 µS/cm to almost 1450 µS/cm in the tenth cycle of plasma treatment. Moreover, a high power yielded an excessive decontamination level, but also in the grand production of nitric acid. On the other hand, lower values of power lead to less successful endpoints, over 85% and less than 60% of degraded PRO when 35 W and 15 W were applied, respectively. Accordingly, under these conditions, the total production of ions was less intensive. The maximum conductivity value was less than 500 µS/cm for PRO treated with plasma generated by 35 W of power, and under 130 µS/cm for 15 W. To elude the exact role of reactive species, a pair of scavengers were added to a PRO solution. Both t-butanol and p-benzoquinone cut down the degradation efficiency to roughly 50%, which is 35% less than without scavengers. This result indicates an important role of hydroxyl radicals and superoxide anion radicals in air¬-generated nonthermal plasma. Advanced oxidation using this type of nonthermal plasma reactor enables the production of active species in situ while working in ambient conditions. The effectiveness of plasma treatment was confirmed with the degradation of propranolol, as a model compound for common waterborne pharmaceuticals.This conference paper was presented at the 21st European Meeting on Environmental Chemistry, held in Novi Sad, Serbia (30th of November - 3rd of December, 2021). https://emec21.rs

Plasma assisted degradation of pharmaceutics in water: propranolol hydrochloride as a model compound

Propranolol hydrochloride (PRO, Fig. 1), beta-blocker, is poorly degradable in wastewater treatment plants. Because of its wide use, it could pose a threat to aquatic organisms and water users. [1] The non-thermal plasma reactor (Fig. 2) is tested for degradation of propranolol hydrochloride solution (100 ppm), using different gases under the same electrical conditions (35 W of power dissipated in plasma). The concentration of PRO in samples was quantified using HPLC-DAD (213 nm), with acetonitrile and water (70/30 V/V) as eluents. The retention time of PRO was 5.100 min. The most successful propranolol hydrochloride degradation was achieved using Ar with O2 (80/20 V/V), applying 35 W of power dissipated in plasma, almost 80 % in the 1stcycle of treatment (Fig. 3). The best results with air are slightly over 80 % but in the 10th cycle of plasma reactor treatment. The presence of N2 in the air decreases the availability of reactive oxygen species, as shown in [2]. This non-thermal plasma is successful at the degradation of organic pollutants in water, such as propranolol hydrochloride, under given conditions. The level of propranolol hydrochloride degradation can be increased modifying the composition of feed gas, with best results using Ar with O2.Poster presentation held at Japan-Serbia Environmental Exchange Symposium (21. 2. 2020.), Belgrade, Serbia. Japan and Serbia have an ongoing collaboration in the environmental field. More than half of the Serbian Ministry of Environmental Protection staff were trained in Japan through various JICA programs. Exchanges are also starting in the business fields such as waste power generation. SATREPS project, “Spatial Environment Analysis and Advanced Metal Recovery System for Sustainable Resource Development” which was developed as a Global Science and Technology Cooperation Program for Global Issues was conducted for five years since April 2015. JICA technical cooperation project at the grassroots level, the “Capacity Building for Analysis and Reduction Measures of Persistent Organic Pollutants in Serbia” has been held for three years since March 2014. A new JICA project, “Environmental Improvement in Pancevo, Serbia through the Collaborations among Academia, Government, Industry and Citizens” has the same framework and will last three years from February 2020. This project is not limited to the reduction of hazardous chemicals, but aims to create a healthy environment for both humans and animals, thus the project has a working name: “Stork Project”. In this symposium, both SATREPS and JICA Partnership, the environmental exchange projects between Japan and Serbia, will jointly hold lectures and poster displays with the aim of encouraging environmental exchange between Japan and Serbia. See more here: [http://chem.bg.ac.rs/pz/news1.py?q=2506&l=0

Dielectric barrier discharge in water solution treatment

Application of coaxial dielectric barrier discharge (DBD) reactor for treatment of different water solutions was studied. In this reactor the circulating liquid is a part of discharge electrode configuration. Thus liquid is directly exposed to UV radiation and reactive species like ozone, radicals, ions and electrons. This configuration of DBD also offers to operate the plasma with and without water falling film at one of the electrodes. Thus it can act as a plasma reactor for gas treatment and as a scrubber for soluble compounds in a gas phase, simultaneously. Here we present measurement of hydroxyl radical ("OH) in plasma treated distilled water as well as treatment of phenols, textile dyes, medicaments, herbicides and detergents

Supplementary material for the article: Aonyas, M. M.; Nešić, J.; Jović, M.; Marković, M.; Dojčinović, B.; Obradović, B.; Roglić, G. M. Degradation of Triton X-100 in Water Falling Film Dielectric Barrier Discharge Reactor. Clean - Soil, Air, Water 2016, 44 (4), 422–429. https://doi.org/10.1002/clen.201500501

Supplementary material for: [https://doi.org/10.1002/clen.201500501]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1920

Application of non-thermal plasma reactor for degradation and detoxification of high concentrations of dye Reactive Black 5 in water

Degradation and detoxification efficiency of high concentrations of commercially available reactive textile dye Reactive Black 5 solution (40, 80, 200, 500, 1000 mg L-1), were studied. Advanced oxidation processes in water falling film based on dielectric barrier discharge in a non-thermal plasma reactor were used. For the first time, this reactor was used for the treatment of high concentrations of organic pollutants such as reactive textile dye Reactive Black 5 in water. Solution of the dye was plasma treated in a thin aqueous solution film that was constantly regenerated. The reactor works as a continuous flow reactor and the electrical discharge itself takes place at the gas-liquid interphase. The dye solution was recirculated through the reactor with an applied energy density of 0-374 kJ L-1. Decolorization efficiency (%) was monitored by UV-Vis spectrophotometry. Samples were taken after every recirculation (similar to 22 kJ L-1) and decolorization percentage was measured after 5 min and 24 h post plasma treatment. The efficiency of degradation (i.e., mineralization) and possible degradation products were also monitored by determination of the chemical oxygen demand (COD) and by ion chromatography (IC). Initial toxicity and toxicity of the solutions after the treatment were studied using Artemia salina test organisms. Efficiency of decolorization decreased with the increase of the dye concentration. Complete decolorization, high mineralization and non-toxicity of the solution ( lt 10 %) were acomplished after plasma treatment using energy density of 242 kJ L-1, while the initial concentrations of Reactive Black 5 were 40 and 80 mg L-1

Simultaneous influence of Stark effect and excessive line broadening on the H

The aim of this paper is to study the combined influence of the Stark effect and the excessive Doppler broadening on the Balmer alpha line in hydrogen discharges. Since this line is a good candidate for measuring electric field in various types of discharges with different gas compositions, a simple method for field measurement based on polarization spectroscopy is developed, that includes all the excitation mechanisms. To simultaneously test the flexibility of the fitting procedure and investigate the excessive broadening, we applied the fitting procedure on line profiles obtained at a range of conditions from two different discharges. The range of pressures and voltages was examined in an abnormal glow and in dielectric barrier discharge operating with hydrogen gas. The model fitting function was able to respond and follow the change in the line profile caused by the change of conditions. This procedure can therefore be recommended for electric field measurement

Electrical Resistivity of Plasma Treated Viscose and Cotton Fabrics with Incorporated Metal Ions

Cellulose fabrics (viscose and cotton) were treated with atmospheric pressure dielectric barrier discharge (DBD) in air. After DBD treatment, samples were characterized and volume electrical resistance was measured under different relative humidity conditions (phi=40-55 %). Results have shown that DBD treatment increases wettability and polar surface functional groups content, which consequently causes a decrease of volume electrical resistivity of cellulose fabrics in measured relative humidity range (phi=40-55 %). Metal ions (silver, copper, and zinc) were incorporated in untreated and plasma treated samples through sorption from aqueous solutions and incorporation of metal ions into plasma treated cellulose samples decreased electrical resistivity even further. Resistivity of cotton and viscose fabrics with incorporated metal ions followed the order Zn2+ gt Cu2+ gt Ag+. The most pronounced decrease, for entire order of a magnitude, was obtained by modification of cotton fabric with DBD and silver ions, where value of resistivity dropped from G Omega to a several dozens of M Omega

Surface cleaning of raw cotton fibers with atmospheric pressure air plasma

In this work, a possibility to use atmospheric pressure plasma treatment to clean cotton fibers surface was investigated. Dielectric barrier discharge (DBD) operating in air was used as plasma source. After plasma treatment, cotton fibers were characterized using several surface techniques: SEM, XPS, ATR-FTIR and zeta potential measurement; also wettability was evaluated using capillary height measurement. Results of investigation showed that plasma treatment primarily affects cuticle and primary wall of cotton which provides cleaning of the fibers surface. This caused increase of polar groups accessibility and better wettability of cotton samples. An attempt has been made to locate influence of plasma treatment on different structural layers of cotton fibers using different surface techniques. In addition, surface charge was investigated through measuring streaming potential and a connection was established between zeta potential and plasma treatment time. Furthermore, it was shown that measuring of zeta potential could be used as an additional technique to track changes and elucidate mechanisms of plasma treatment influence on cotton fibers