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The potential of decayed wood was investigated as a raw material to produce activated carbon. Both sound and decayed beech wood specimens were subjected to chemical activation with ZnCl2 at a carbonization temperature of 400 °C and 75% impregnation ratio to produce activated carbon. The produced activated carbon was tested using Brunauer--Emmett--Teller, Fourier transform infrared, scanning electron microscopy, and thermogravimetric analyses to investigate its properties. The activated carbon was used to adsorb rhodamine B dye in an aqueous solution. Additionally, to investigate the impact of activated carbon surface modification on the adsorption of rhodamine B dye, both kinds of activated carbon underwent surface modification using dielectricbarrier discharge (DBD) plasma at a high frequency of 20 kHz in the air atmosphere for 20 min at a voltage level of 10 kV. The modification of the activated carbon substantially improved its characteristics, resulting in a 20% increase in rhodamine B removal for the activated carbon derived from sound wood and a 12% increase for the activated carbon derived from decayed wood. The utilization of DBD air plasma in this method is suitable because of its simplicity, cost-effectiveness, and improved adsorption capacity in activated carbon. [ABSTRACT FROM AUTHOR]

The potential of decayed wood was investigated as a raw material to produce activated carbon. Both sound and decayed beech wood specimens were subjected to chemical activation with ZnCl2 at a carbonization temperature of 400 °C and 75% impregnation ratio to produce activated carbon. The produced activated carbon was tested using Brunauer–Emmett–Teller, Fourier transform infrared, scanning electron microscopy, and thermogravimetric analyses to investigate its properties. The activated carbon was used to adsorb rhodamine B dye in an aqueous solution. Additionally, to investigate the impact of activated carbon surface modification on the adsorption of rhodamine B dye, both kinds of activated carbon underwent surface modification using dielectric-barrier discharge (DBD) plasma at a high frequency of 20 kHz in the air atmosphere for 20 min at a voltage level of 10 kV. The modification of the activated carbon substantially improved its characteristics, resulting in a 20% increase in rhodamine B removal for the activated carbon derived from sound wood and a 12% increase for the activated carbon derived from decayed wood. The utilization of DBD air plasma in this method is suitable because of its simplicity, cost-effectiveness, and improved adsorption capacity in activated carbon.

The effect of non-thermal discharge plasma (DBD) on the inhibition of both gram-positive and gram-negative biofilms bacteria was examined at different plasma exposure times and gas flow. This effect induces damage to aqueous plasmid DNA. It reveals inactivation in bacterial biofilms for both types of bacteria with an increase in time of direct exposure to plasma and an increase in gas flow. The presence of positive bacteria outweighs the negative bacteria in susceptibility to inhibition. The resulting fractions of the DNA indicate whole DNA double-strand breaks and were determined using agarose gel electrophoresis. The damage level induced in the plasmid DNA is also enhanced with increased plasma irradiation time.

While methane-powered vehicles produce fewer greenhouse gas emissions in comparison to conventional fuel vehicles, there is a significant amount of methane slip in their exhaust that needs to be treated. This study investigates non-thermal plasma (NTP) assisted catalytic methane oxidation as an alternative method for the low temperature methane slip abatement applicable to the exhaust of biogas methane-powered vehicles. It is concluded that high CH4 conversion and CO2 selectivity can be obtained using NTP-catalysis at low temperature with Pd/Al2O3 found to be the most promising candidate among all catalysts tested. In addition, it was found that CH4 conversion efficiency was dependent on the feed gas components and gas hourly space velocity as well as how the activation energy is introduced. For example, a combination of plasma and external heat supply provides advantages in terms of CH4 conversion along with lower plasma energy consumption. The presence of N2 and O2 in the feed gas during NTP-catalytic methane oxidation results in unfavourable NOX formation which linearly increases with CH4 conversion. These results conclude that the most suitable aftertreatment option involves the combination of an oxidation catalyst with plasma to target the hydrocarbon and CH4 oxidation, followed by an ammonia-SCR system to convert the NOX formed in plasma assisted zone. [ABSTRACT FROM AUTHOR]

The effect of non-thermal discharge plasma (DBD) on the inhibition of both gram-positive and gram-negative biofilms bacteria was examined at different plasma exposure times and gas flow. This effect induces damage to aqueous plasmid DNA. It reveals inactivation in bacterial biofilms for both types of bacteria with an increase in time of direct exposure to plasma and an increase in gas flow. The presence of positive bacteria outweighs the negative bacteria in susceptibility to inhibition. The result fractions of the DNA are indicate the whole DNA double-strand breaks and were determined using agarose gel electrophoresis. The damage level induced in the plasmid DNA is also enhanced with increased plasma irradiation time. [ABSTRACT FROM AUTHOR]

A series of bi-metallic layered double hydroxide derived materials, containing a fixed amount of Ni promoted with various amounts of Fe were obtained by co-precipitation. The synthesized materials were characterized by X-ray diffraction (XRD), temperature-programmed reduction (H 2 -TPR), temperature-programmed desorption of CO 2 (CO 2 -TPD), elemental analysis and low temperature N 2 sorption and tested as catalysts in CO 2 methanation at atmospheric pressure. The obtained results confirmed the formation of mixed nano-oxides after thermal decomposition of the precursor and suggest successful introduction of both nickel and iron into the layers of Layered Double Hydroxides (LDHs). The introduction of Fe into the layered double hydroxides changed the interaction between Ni and supports matrix as proven by temperature programmed reduction (H 2 -TPR). The introduction of low amount of iron influenced positively the catalytic activity in CO 2 methanation at 250 °C, with CO 2 conversion increasing from 21% to 72% with CH 4 selectivity ranging from 97 to 99% at 250 °C. No other products, except CH 4 and CO were registered during the experiments. In order to enhance the catalytic activity a non-thermal plasma created by dielectric barrier discharge was applied. The obtained results prove that plasma could replace the need of heating the reactor in a dynamic system working temporarily when excess energy is available. • Ni-containing Fe-promoted hydrotalcite-derived catalysts for CO 2 methanation. • Both nickel and iron were successfully introduced into hydrotalcites structure. • Fe addition increased the reducibility and changed the distribution of basic sites. • Fe influenced positively the catalytic activity in thermal and plasma CO 2 methanation. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to study the butyraldehyde (Buty) conversion using dielectric barrier discharge (DBD) in a continuous reactor at pilot scale. One of the focused-on parameters in this study is relative humidity, which effect on (i) butyraldehyde removal (ii) selectivity of CO 2 and CO, and (iii) intermediate byproducts and ozone formation was investigated using a DBD reactor with planar configuration. The results showed that at pilot scale, adding a small amount of water vapor in air enhances the processes performance and 10% increase in Buty removal efficiency was observed. A kinetic degradation model was also proposed, which takes into account the relative humidity influence. Active species due to water dissociation are integrated in the model. To represent the chemical degradation pathway, we supposed, in a first step, that an equivalent intermediate compound (EI) is formed directly from Buty. Then, in a second step, this EI is oxidized by active species into CO 2 and CO in the discharge zone. This approach that also considers the competition effect between actives species improved the concordance between simulated results and experiments with a satisfactory overall description of the degradation and byproducts formation. [ABSTRACT FROM AUTHOR]

Banana-plantain pseudo-stem fibers (BPF) were modified using epichlorohydrin (EP), acetic anhydride (AA), and a combination of the two (AA_EP), and three dielectric barrier discharge (DBD), plasma treatments, at 1, 3, and 6 kW min-1 m-2. Untreated and treated BPF samples were characterized via Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), mechanical tensile and wettability tests. The FT-IR spectrum, the SEM images, and the TGA suggest a loss of lignin, hemicellulose, impurities, and waxes. These effects together with the modification of the OH and C-C groups, respectively by the chemical and plasma treatments, increased the hydrophobicity of the treated BPF. The chemical treatments promoted the esterification and crosslinking of the free OH groups in BPF, leading the BPF treated chemically to be more rigid than plasma-treated BPF. SEM images show that plasma-treated BPF have a rougher, more irregular surface than chemical treated BPF. The fiber wettability, measured by the contact angle assay, decreased after both treatments, which is an important characteristic for a filler material in composites. [ABSTRACT FROM AUTHOR]

Despite numerous publications about the versatility of the technique by dielectric barrier discharge (DBD), especially in emerging applications such as biological and chemical decontamination, little is presented on the influence of process parameters. In this paper we analyzed the influence of process parameters on the active species of the plasma formed when air is used as the atmosphere. We analyzed the influence of the distance between electrodes and applied voltage, and the pulse rate applied. The analyzes were performed species diagnosing the plasma by optical emission spectroscopy (OES). These results were correlated with data from the power consumed in the production process of plasma obtained from the Lissajous figures. The equipment used has a maximum DBD production efficiency of atmospheric plasma with the distance between electrodes 0.5 mm set at 15 kV and voltage frequency of 500 or 600 Hz depending on the species one wishes active in greater quantity N2 357nm or N2 337nm respectively. [ABSTRACT FROM AUTHOR]

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In the present work, the oxidation of isovaleraldehyde, a typical pollutant of indoor air, is investigated by using two different plasma DBD reactors: cylindrical and planar reactor. The study of the influence of the specific energy shows that its increment is accompanied by an increase of the removal efficiency. In fact, when specific energy extends three times, the removal efficiency is increased from 5 to 40 %. Moreover an increase of the specific energy induces a higher mineralization due to byproducts oxidation with reactive species production. The same behaviour is observed with ozone production. A generic mathematical model is developed to represent the experimental results obtained. This model is based on several mass transfer steps occurring in series between bulk and plasma phases. The degradation reaction mechanism is supposed to occur on two steps. Firstly, isovaleraldehyde leads to the formation of a fictitious equivalent intermediate (EI). In a second step, EI is transformed into CO and CO2. This approach gives a good agreement between modelling and experiments with a satisfactory overall description of byproducts formation. This original approach allows for the simulation of plasma oxidation kinetics process without knowing the complete chemical pathway. [ABSTRACT FROM AUTHOR]

Abstract: The methane oxidation reaction was studied as a function of temperature for a gas mixture representative of a combined heat power (CHP) within a dielectric barrier discharge (DBD) reactor. The effect of energy deposition was studied, with energy deposition ranging from 36 to 58JL−1, to maintain a low NO x formation at high temperature. In the current study, we also investigated the combined process of a dielectric barrier discharge and γ-alumina noble metal catalysts such as platinum and palladium. In order to separate the catalytic effects from the plasma activation, the work included both purely catalytic and plasma activation processes using a complete CHP mixture with 4% of water in the feed. It was found that the presence of water leads to increase the methane conversion in purely plasma activation processes. Moreover, a higher efficiency for methane oxidation in CHP conditions was observed with the plasma–Pd(X)/Al2O3 systems. [Copyright &y& Elsevier]

Abstract: The total oxidation of methane was carried out within a dielectric barrier discharge (DBD) reactor. The effect of energy deposition was studied, with energy deposition ranging from 36 to 100JL−1. In the current study, we also investigated the combined process of a dielectric barrier discharge and γ-alumina catalyst in the total oxidation of methane. In order to separate the catalytic effects from the plasma activation, the work included both purely catalytic and plasma activation processes. It was found that the catalytic activity depended on the energy deposition and the temperature. The plasma process leads to methane conversion in the temperature range of 300–500°C, whereas, methane conversion was only active above 425°C when only a catalyst was present. Moreover, the addition of NO x and CO2 in the feed was also studied. This addition does not affect the methane conversion in the absence or in the presence of catalyst. Finally, the presence of γ-alumina leads to CO+CO2 as products of the total oxidation of methane, whereas for the plasma-induced process, CO is the major product of the reaction. [Copyright &y& Elsevier]

O uso do plasma (DBD) surge como uma alternativa tecnológica promissora no tratamento pré-germinativo de sementes, principalmente quando apresentam dormência tegumentar. A leucena Leucaena leucocephala (Lam) de wit é uma espécie arbórea de importância singular para o semiárido brasileiro com potencial de uso variado. O objetivo da pesquisa foi avaliar o efeito da aplicação do plasma DBD na superação de dormência de sementes de leucena, sendo as mesmas submetidas aos tratamentos com e sem aplicação do plasma. O experimento foi conduzido no laboratório de Plasma do Departamento de Ciências Exatas. A semeadura foi realizada em bandejas plásticas 26 x 18 x 5,5 cm utilizando como substrato areia lavada previamente esterilizada. O delineamento adotado foi inteiramente casualizado, com 2 tratamentos com e sem aplicação do plasma, em 4 repetições, sendo a unidade experimental representada por uma bandeja contendo 25 sementes. Foram avaliadas as seguintes características de germinação e vigor: primeira contagem de germinação, índice de velocidade de emergência, tempo médio de germinação, percentagem de germinação e massa seca total. Fazendo um comparativo do tratamento com plasma e sem plasma, observou-se incremento em termos percentuais de 64% para primeira contagem, 42% para germinação, 59% para índice de velocidade de emergência e 51% para massa seca total. O tratamento de sementes a base de plasma DBD mostrou-se promissor na superação de dormência de sementes de leucena. [ABSTRACT FROM AUTHOR]