Diagnostics and applications of dielectric barrier discharge in contact with water.

Ova doktorska disertacija posvećena je istraţivanju dielektričnog barijernog praţnjenja u kontaktu sa vodom i njegovim primenama. U dielektričnom barijernom praţnjenju (DBP) sa padajućim vodenim filmom ispitana je interakcija plazme i tečnosti sa karakterizacijom fizičkih i hemijskih osobina gasne i tečne faze. Osnovni doprinos ovog istraţivanja je unapreĎenje razumevanja hemijskih procesa koje neravnoteţna plazma na atmosferskom pritisku indukuje u tečnostima. Plazma u DBP reaktoru ispitivana je uz pomoć emisione spektroskopije i električnih merenja. Ispitano je formiranje hidroksil radikala (˙OH) i dugoţivećih hemijskih vrsta (H2O2, O3, NO3 i NO2 ) u vodi i dimetil sulfoksidu koji su izloţeni delovanju neravnoteţne plazme u DBP reaktoru sa vodenim filmom u zavisnosti od gasne atmosfere (vazduh, azot, kiseonik, argon i helijum). U fokusu ovog istraţivanja bilo je formiranje hidroksil radikala i mogući uticaj njegovog zahvatanja hemijskom sondom (dimetil sulfoksid) na formiranje dugoţivećih vrsta. UtvrĎeno je da reakcija rekombinacije hidroksil radikala suštinski odreĎuje formiranje vodonik-peroksida u praţnjenjima u vazduhu, azotu i argonu. Za prostorno- vremensko istraţivanje interakcije plazme sa vodom korišćen je helijumov plazmeni mlaz u kontaktu sa vodom. Snimci razvoja praţnjenja dobijeni iCCD kamerom otkrivaju da interakcija praţnjenja sa tečnom metom moţe biti produţena nekoliko puta u zavisnosti od radnih parametara. Merene su raspodele emisije nekoliko ekscitovanih hemijskih vrsta da bi se identifikovao glavni mehanizam ekscitacije. Korišćenjem metoda Štarkove polarizacione spektroskopije, izmerena je raspodela jačine električnog polja u plazmenom mlazu koji interaguje sa tečnom metom. Ova merenja podrţana su Šlirenovom vizuelizacijom plazmenog mlaza i vodene mete. Pokazano je da neznatne promene neelektričnih parametara, kao što je udaljenost mete i brzina protoka gasa, mogu u potpunosti da promene prirodu praţnjenja. Merene vrednosti električnog polja su u opsegu 8-30 kV/cm, i zavise samo od protoka gasa i rastojanja mete, i saglasne su sa rezultatima modelovanja. Šlirenovom vizuelizacijom demonstrirana je interakcija izmeĎu protoka gasa i same plazme. Poseban doprinos ove studije je dokumentovan uticaj plazmenog mlaza na mešanje tečnosti. U okviru istraţivanja primena DBP sa vodenim filom ispitano je uklanjanje isparljivih ugljovodonika u gasnoj fazi. Demonstrirana je degradacija undekana i toluena sa smanjenom emisijom nusproizvoda kao i konverzija nerastvorljivih jedinjenja u rastvorljiva. Ispitana je inaktivacija različitih vrsta mikroorganizama u tečnostima. Pri uklanjanju zagaĎujućih supstanci u tečnoj fazi ispitan je uticaj različitih homogenih katalizatora i njihove doze na proces degradacije herbicida mezotriona, farmaceutskog jedinjenja ibuprofena i nikotina u DBP sa vodenim filmom i pokazana je visoka (do 99 %) efikasnost degradacije.The subject of the presented thesis is the study of dielectric barrier discharge in contact with water and its applications. In water falling film dielectric barrier discharge (DBD) plasma- liquid interaction has been studied, with characterization of physical and chemical properties of the gas phase and the liquid phase. The main contribution of this research is improvement of understanding of chemical processes induced in liquids by nonthermal atmospheric/pressure plasmas. Plasma in DBD reactor has been studied by optical emission spectroscopy and electrical measurements. The formation of hydroxyl radical (˙OH) and long-living chemical species (H2O2, O3, NO3 and NO2 ) generated in water and in dimethyl sulfoxide in water falling film DBD in dependence on the gas atmosphere (air, nitrogen, oxygen, argon and helium) was studied. The focus of this study was the formation of hydroxyl radical and the influence of ˙OH scavenging by dimethyl sulfoxide on the formation of long-living species. It was found that formation of hydrogen peroxide in air, nitrogen and argon discharges is determined by recombination reaction of hydroxyl radicals. For spatio-temporally resolved study of plasma-liquid interaction helium plasma jet with liquid target was used. ICCD recordings of the discharge development revealed that discharge interaction with the target can be elongated several times, depending on the operating parameters. Distributions of the emissions of several excited chemical species are measured in order to identify the main excitation mechanisms. Utilizing the method of Stark polarization spectroscopy, the electric field strength distribution measurements in helium plasma jet interacting with a liquid target are also obtained. Measurements are supported by simultaneous Schlieren imaging of both the effluent of plasma jet and water target. It was shown that the slight change of the non-electrical parameters, such as target distance and the gas flow rate can completely change the nature of the discharge. Measured electric field values are in range of 8-30 kV/cm, and depend only on the gas flow and the target distance, and they are in reasonable agreement with the modeling outcomes. Schlieren imaging demonstrated strong interaction between the gas flow and the plasma itself. Special outcome of this article is documented influence of the plasma jet discharge on the mixing of the liquid. As part of the research on the applications of water falling film DBD, the removal of volatile hydrocarbons in the gas phase was investigated. Degradation of undecane and toluene with reduced emission of by-products as well as conversion of insoluble compounds to soluble was demonstrated. Inactivation of different types of microorganisms in liquids was investigated. The influence of various homogeneous catalysts and their dosage on the degradation process of the mesotrione herbicide, the pharmaceutical compound ibuprofen and nicotine in water falling film DBD was examined and high degradation efficiency (up to 99%) was demonstrated

Hydrogen Peroxide Production in Water Treated by Non-Thermal Plasma in Different Atmospheres

Chemical properties of distilled water treated by non-thermal plasma reactor were studied. Hydrogen-peroxide production, pH value and conductivity in distilled water were measured after plasma-treatment in air, argon and argon-oxygen mixture as working gases. Water falling film dielectric barrier discharge (DBD) reactor 1 was used for water treatment. Direct contact of water film with plasma in this reactor enables efficient transfer of reactive species generated in plasma to liquid phase. For optimization of reactive species production frequency and amplitude of the applied voltage were varied. Chemical characterization of water treated by DBD generated in different gases shows that hydrogen peroxide production in argon reaches yield of 0.78 g/kWh, while in air it was 0.19 g/kWh. Both measurements were made with 35 W of power dissipated in plasma. Moreover, significant influence of gas atmosphere was observed in measurements of pH value and conductivity which imply that production of ions is about 15 times greater in water treated with plasma generated in air than in argon. Advanced oxidation using this type of non-thermal plasma reactor enables production of active species in situ, while working in ambient conditions.1 Effectiveness of plasma treatment was already confirmed with degradation of some waterborne pharmaceuticals.2 This opens opportunities for new studies of plasma oxidation of pharmaceuticals in aquatic environments

Hydrogen Peroxide Production in Water Treated by Non-Thermal Plasma in Different Atmospheres

Chemical properties of distilled water treated by non-thermal plasma reactor were studied. Hydrogen-peroxide production, pH value and conductivity in distilled water were measured after plasma-treatment in air, argon and argon-oxygen mixture as working gases. Water falling film dielectric barrier discharge (DBD) reactor 1 was used for water treatment. Direct contact of water film with plasma in this reactor enables efficient transfer of reactive species generated in plasma to liquid phase. For optimization of reactive species production frequency and amplitude of the applied voltage were varied. Chemical characterization of water treated by DBD generated in different gases shows that hydrogen peroxide production in argon reaches yield of 0.78 g/kWh, while in air it was 0.19 g/kWh. Both measurements were made with 35 W of power dissipated in plasma. Moreover, significant influence of gas atmosphere was observed in measurements of pH value and conductivity which imply that production of ions is about 15 times greater in water treated with plasma generated in air than in argon. Advanced oxidation using this type of non-thermal plasma reactor enables production of active species in situ, while working in ambient conditions.1 Effectiveness of plasma treatment was already confirmed with degradation of some waterborne pharmaceuticals.2 This opens opportunities for new studies of plasma oxidation of pharmaceuticals in aquatic environments

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

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

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

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

Synthesis and in vitro antitumour activity of new goniofufurone mimics with thiophene ring at the C-7 position

Ostvarena je višefazna sinteza novih mimetika (+)-goniofufurona (1) sa tiofenskim prstenom umesto fenil grupe u položaju C-7 polazeći iz D-glukoze (Shema 1). Ispitana je in vitro citotoksična aktivnost novosintetizovanih mimetika prema odabranim tumorskim ćelijskim linijama, kao i prema jednoj normalnoj ćelijskoj liniji (fetalni fibroblasti pluća, MRC-5).Multiphase synthesis of (+)-goniofufurone (1) mimetics with thiofene ring instead of phenyl group at the C-7 position is completed using D-glucose as a starting compound (Scheme 1). In vitro cytotoxicity of newly synthetized analogues against eleven human tumour cell lines and against a single normal cell line (MRC-5) was evaluated

Immune response to gut escherichia coli and susceptibility to adjuvant arthritis in the rats

We have investigated the humoral immune response to antigens of predominant gut aerobic bacterial strains (i.e. Escherichia coli) over the course of adjuvant arthritis and oil-induced arthritis in two inbred rat strains: Dark Agouti (DA) and Albino Oxford (AO). We report the presence of antibodies specific to proteins of Escherichia coli in molecular weight range between 20-30 kDa in sera of diseased DA rats, and the absence of these antibodies in the sera of AO rats. In DA rats, CFA and IFA provoked a stronger antibody response to Escherichia coli, especially of the IgG2b antibody class. Intramuscular administration of Escherichia coli preceding the adjuvant arthritis induction had no effect on the development and course of disease, as well as on the activation of T cells in the draining inguinal lymph nodes. Higher serum levels of natural and induced IgA antibodies, combined with a higher CD3(+)CD26(+) cell percentage were found in AO rats. The observed correlation between the serologic response to commensal flora and rats' genetic background as a defining factor for arthritis susceptibility may contribute to the process of creating a favorable (or less favorable) milieu for arthritis development

Association of acute Babesia canis infection and serum lipid, lipoprotein, and apoprotein concentrations in dogs

Background: Babesia canis infection induces a marked acute phase response (APR) that might be associated with alteration in lipid and lipoprotein metabolism and disease prognosis. Hypothesis: Dogs with B. canis-induced APR develop dyslipidemia with altered lipoprotein concentration and morphology. Animals: Twenty-nine client-owned dogs with acute B. canis infection and 10 clinically healthy control dogs. Methods: Observational cross-sectional study. Serum amyloid A (SAA) was measured using ELISA. Cholesterol, phospholipids, and triglycerides were determined biochemically. Lipoproteins were separated using agarose gel electrophoresis. Lipoprotein diameter was assessed by polyacrylamide gradient gel electrophoresis; correlation with ApoA-1 (radioimmunoassay) and SAA was determined. Results: Dogs with B. canis infection had a marked APR (median SAA, 168.3 μg/mL; range, 98.1-716.2 μg/mL) compared with controls (3.2 μg/mL, 2.0-4.2 μg/mL) (P lt .001). Dogs with B. canis infection had significantly lower median cholesterol (4.79 mmol/L, 1.89-7.64 mmol/L versus 6.15 mmol/L, 4.2-7.4 mmol/L) (P =.02), phospholipid (4.64 mmol/L, 2.6-6.6 mmol/L versus 5.72 mmol/L, 4.68-7.0 mmol/L) (P =.02), and α-lipoproteins (77.5%, 27.7%-93.5% versus 89.2%, 75.1%-93.5%) (P =.04), and higher ApoA-1 (1.36 U, 0.8-2.56 U versus 0.95 U, 0.73-1.54 U) concentrations (P =.02). Serum amyloid A correlated with high-density lipoproteins (HDLs) diameter (rho =.43; P =.03) and ApoA-1 (rho =.63, P lt .001). Conclusions and Clinical Importance: Major changes associated with B. canis-induced APR in dogs are related to concentration, composition, and morphology of HDL particles pointing to an altered reverse cholesterol transport. Parallel ApoA-1 and SAA concentration increase is a unique still unexplained pathophysiological finding