•Simple synthesis procedure with good reproducibility.•Preparation of spherical, rice grain-like, needle-like and plate-like CuO NMs.•Antimicrobial activity and mechanism.•Shape dependent ...performance.
Present study deals with the preparation of differently shaped copper oxide nanomaterials (CuO NMs) using simple, reproducible wet chemical and hydrothermal approach. The influence of polyethylene glycol on the morphological control was also studied. The prepared nanomaterials exhibited new types of surface morphologies such as rice grain-like, needle-like and plate-like. The Fourier transform infrared spectra and the X-ray photoelectron spectra of all the samples showed identical chemical functional groups and did not exhibit the presence of any impurities. They exhibited good stability in the aqueous environment with the zeta potential values between −25 and −27mV. The shape dependent anti-bacterial property of the prepared CuO NMs was evaluated against two Gram-positive bacteria namely Streptococcus iniae and Streptococcus parauberis and two Gram-negative bacteria such as Escherichia coli and Vibrio anguillarum. Among three CuO NMs, the plate-like CuO NMs displayed more powerful antibacterial activity than grain or needle shaped CuO NMs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•The degradation behavior of several sulfonamide antibiotics were characterized.•The intermediates and byproducts formed during the plasma treatment were identified.•The degradation pathways of the ...antibiotics were proposed.
The degradation of sulfonamide antibiotics, such as sulfathiazole (STZ), sulfamethazine (SMT) and sulfamethoxazole (SMZ) in water was carried out with a nonthermal dielectric barrier discharge plasma reactor operating under dry air or oxygen. In order to understand the degradation pathways of the antibiotics, the plasma-treated aqueous antibiotic solutions were characterized by various techniques such as UV–visible spectroscopy, ion chromatography, liquid chromatography coupled to a tandem mass spectrometer (LC–MS/MS), pH and electrical conductivity measurements, and total organic carbon analysis. The degradation rates of the antibiotics investigated were found to be higher with pure oxygen than with dry air, and decreased in the order: SMT>STZ>SMZ. As the degradation proceeded, the characteristic absorption peaks gradually decreased and the solution pH and conductivity increased, indicating that the antibiotics were being mineralized. The ion chromatography identified both inorganic (SO42−, NO3− and NH4+) and organic ions (acetate, formate and oxalate) as the stable degradation products. After 60-min plasma treatment with oxygen, the percentage of the S atoms transformed into SO42− was in the range of 66.9–86.4%, depending upon the type of antibiotics, while of the percentage of the N atoms transformed into NH4+ and NO3− was in the range of 15.7–33.2%. The possible degradation pathways of the antibiotics were proposed from the identified intermediate products formed during the degradation, which elucidates that the hydroxylation of the ring structures in the antibiotic molecules initiates the degradation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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•Energy-efficient VOC abatement by cyclic adsorption/plasma-catalytic treatment.•13X zeolite-supported Ag and metal oxides as dual functional adsorbent/catalyst.•Adsorption ...enhancement by the co-incorporation of Ag and metal oxide into 13X zeolite.•Bimetallic Ag–Fe2O3 capable of effectively reducing O3 and increasing VOC oxidation.
Dynamic adsorption of ethylene on 13X zeolite-supported Ag and Ag–MxOy (M: Co, Cu, Mn, and Fe), and plasma-catalytic oxidation of the adsorbed ethylene were investigated. The experimental results showed that the incorporation of Ag into zeolite afforded a marked enhancement in the adsorptivity for ethylene. The addition of transition metal oxides was found to have a positive influence on the ethylene adsorption, except FexOy. The presence of the additional metal oxides, however, appeared to somewhat interrupt the diffusion of ozone into the zeolite micro-pores, leading to a decrease in the plasma-catalytic oxidation efficiency of the ethylene adsorbed there. Among the second additional metal oxides, FexOy was able to reduce the emission of ozone during the plasma-catalytic oxidation stage while keeping a high effectiveness for the oxidative removal of the adsorbed ethylene. The periodical treatment consisting of adsorption followed by plasma-catalytic oxidation may be a promising energy-efficient ethylene abatement method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•High ethylene adsorption capacity of Ag ion-exchanged 13X zeolite.•Oxidative transformation of adsorbed ethylene to CO2 by ozone-induced atomic oxygen.•Fast oxidation of adsorbed ethylene by ...short-lived oxidizing species.•High performance of the hybrid reactor for oxidative removal of adsorbed ethylene.
13X zeolite-supported Ag was employed as the dual-functional adsorbent/catalyst for the plasma-catalytic abatement of dilute ethylene. The adsorbent/catalyst prepared by ion exchange (Ag-EX/13X) exhibited better adsorption capability than the parent 13X and Ag-IM/13X prepared by the impregnation method. The oxidative transformation of the adsorbed ethylene was then performed by using three different reactor configurations such as one-stage (i.e., adsorbent/catalyst in direct contact with plasma), two-stage (i.e., adsorbent/catalyst located downstream of the plasma region), and the combination of the two (hybrid). The oxidation of the adsorbed ethylene to CO2 in the two-stage configuration can be explained by the diffusion of ozone into zeolite micro-pores, which was, however, much slower than in the one-stage and hybrid configurations. When compared at an identical applied voltage of 20kV (inlet ethylene: 200ppm; adsorption time: 100min; plasma oxidation time: 20min), the mineralization efficiency of the hybrid reactor was greater than the sum of those of one- and two-stage reactors, i.e., 63, 42, and 10%, respectively. Using the hybrid configuration, ozone and other reactive species were more effectively produced, thereby shortening the oxidation time of ethylene and therefore achieving a higher energy efficiency which was evaluated to be ca. 2.4g (kWh)−1.
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•The methane conversion shows its maximum in terms of particle size.•The concept of microelectrodes explains the existence of maximum conversion.•By adjusting particle size, ...selectivity can be controlled without catalyst.•In terms of coke formation, non-porous silica particles are favored.•Coke is more produced when large particles are used.
A dielectric barrier discharge (DBD) plasma reactor was employed for non-oxidative coupling of methane. The coupling reaction in the DBD plasma bed was conducted near atmospheric pressure and room temperature. In the bed, dielectric materials such as ordered mesoporous silica (KIT-6), sea sand silica, and α-Al2O3 were employed. This non-catalytic reaction system could successfully activate CH bond to produce methyl radicals and light hydrocarbons without additional thermal energy and oxidant molecules. The gap distance between dielectric particles was determined by their sizes, which was experimentally shown. The effects of gap distance were found significant on the conversion and the selectivity. The existence of maximum conversion at a specific gap distance was experimentally observed and could be described successfully by using a newly developed concept of micro-electrodes. Based on the concept, the minimum threshold electric potential difference between the dielectric particles could be successfully estimated, where the conversion was shown to be maximized. Furthermore, it seemed quite possible to control the compositions of ethane, ethylene, and acetylene by properly adjusting the size or the gap distance of particles.
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We report on the fabrication of hybrid composite poly 4-vinlyphenol (PVPh)/graphene thin film via cost-effective electrospray atomization deposition technique. Thin films fabricated through ...manipulating deposition technique in two different ways which are blending and layer by layer (LBL). For investigation of PVPh/graphene hybrid composite dielectric behavior in comparison to PVPh; three asymmetric MIS thin film capacitors were fabricated, where dielectric thin films (i) PVPh and (ii & iii) hybrid composite thin films PVPh/graphene (blended and LBL) were sandwiched between electrodes i.e. indium tin oxide (ITO) and p-type semiconductor poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The dielectric properties of the thin films were characterized for frequencies 1 to 100 kHz while utilizing the MIS thin film capacitors. The capacitance obtained at 1 kHz frequency for PVPh/graphene (LBL) dielectric layer at the voltage range ±10 volts was 8.5 mF cm −2 while for blended PVPh/graphene thin film the capacitance at the voltage range ±3 volts was 0.40 μF cm −2 and for pristine PVPh as dielectric layer the capacitance at voltage range ±1 volts was 1.45 μF cm −2 . Similarly, even at higher frequencies up to 100 kHz, the PVPh/graphene (LBL) showed stable behavior. Thus, the composite PVPh/graphene (LBL) thin film has a better dielectric nature compared to the composite PVPh/graphene (blended) thin film, even at higher frequencies with larger operational voltage window. This distinguishing nature of the composite PVP/graphene (LBL) is attributed to increase in dielectric constant due to graphene flakes in between PVPh. For the thin films LBL and blended PVPh/graphene, the calculated dielectric constant at 10 kHz is 6.7 and 0.023 while at 100 kHz it is 2 and 0.0167, respectively.
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•(84) Low- and middle-income countries (LMICs) have experienced a resurgence of pertussis.•(74) Maternal aP immunization could prevent pertussis among very young infants.•(84) A dynamic transmission ...model was used to evaluate maternal aP immunization in LMICs.•(82) Maternal aP is cost-effective when infant vaccination coverage is moderate or low.•(85) Maternal aP immunization is not cost-effective in LMICs with infant coverage 90-95%.
This study evaluates the cost-effectiveness of maternal acellular pertussis (aP) immunization in low- and middle-income countries using a dynamic transmission model.
We developed a dynamic transmission model to simulate the impact of infant vaccination with whole-cell pertussis (wP) vaccine with and without maternal aP immunization. The model was calibrated to Brazilian surveillance data and then used to project health outcomes and costs under alternative strategies in Brazil, and, after adjusting model parameter values to reflect their conditions, in Nigeria and Bangladesh. The primary measure of cost-effectiveness is incremental cost (2014 USD) per disability-adjusted life-year (DALY).
The dynamic model shows that maternal aP immunization would be cost-effective in Brazil, a middle-income country, under the base-case assumptions, but would be very expensive at infant vaccination coverage in and above the threshold range necessary to eliminate the disease (90–95%). At 2007 infant coverage (DTP1 90%, DTP3 61% at 1 year of age), maternal immunization would cost < $4,000 per DALY averted. At high infant coverage, such as Brazil in 1996 (DTP1 94%, DTP3 74% at 1 year), cost/DALY increases to $1.27 million. When the model’s time horizon was extended from 2030 to 2100, cost/DALY increased under both infant coverage levels, but more steeply with high coverage. The results were moderately sensitive to discount rate, maternal vaccine price, and maternal aP coverage and were robust using the 100 best-fitting parameter sets. Scenarios representing low-income countries showed that maternal aP immunization could be cost-saving in countries with low infant coverage, such as Nigeria, but very expensive in countries, such as Bangladesh, with high infant coverage.
A dynamic model, which captures the herd immunity benefits of pertussis vaccination, shows that, in low- and middle-income countries, maternal aP immunization is cost-effective when infant vaccination coverage is moderate, even cost-saving when it is low, but not cost-effective when coverage levels pass 90–95%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The dry reforming of methane (DRM) using CO
2
for the production of syngas (H
2
and CO) has received increasing attention for reducing global CO
2
emissions. The main drawback of DRM reactions is the ...limited reusability of the spent catalyst due to carbon deposition on its surface. Thus, designing an appropriate catalytic system is adequate to achieve increased syngas production with low carbon deposition, and developing smart strategies to reuse the carbon deposited spent catalyst is highly desirable. In this work, two dimensional siloxene sheet (silicon analog of graphene oxide) coated nickel foam is examined as a novel catalyst for the DRM reaction. The siloxene/Ni foam catalyst demonstrated superior catalytic performance in terms of conversion efficiencies (for CH
4
and CO
2
) and syngas production (H
2
and CO) with a high H
2
/CO ratio of 1.5. Further, the carbon deposited siloxene/Ni spent catalyst recovered after the DRM reaction was effectively re-utilized as electrodes for a symmetric supercapacitor (SSC) using an organic electrolyte. The fabricated SSC (using the spent catalyst as electrodes) delivered a high device capacitance (24.65 F g
−1
), high energy density (30.81 Wh kg
−1
), and high-power density (15 625 W kg
−1
) with a long cycle life. Considering that the estimated carbon cost for developing a supercapacitor electrode is about $15 per kilogram, our strategy to effectively reutilize the recovered carbon deposited spent catalyst for energy storage applications might be a promising and economical approach for utilization of the spent catalyst.
An effective approach to reuse the carbon deposited spent catalyst (siloxene/Ni foam) after the methane dry reforming process is demonstrated by utilizing them as electrodes for supercapacitor devices.
Developing an energy storage electrocatalyst that excels in efficiency, cost-effectiveness, and long-term stability over numerous charge-discharge cycles is paramount for advancing energy storage ...technologies. In this work, we present a simple and environmentally friendly method to fabricate an asymmetric supercapacitor device (ASCD) as a viable energy storage system. The ASCD features binder-free, oxygen-nitrogen dual functionalized, and sulfurized iron-nickel hydroxysulfide (FNMOS) electrocatalysts, self-grown on nickel foam as a positive electrode, and waste biomass-derived activated carbon (CFAC) as a negative electrode. The FNMOS electrode in a 3-electrode configuration has the highest area-specific capacity of 1.6 mA h cm
−2
at 1 mA cm
2
, and even at a high current density of 10 mA cm
−2
, it maintained 0.94 mA h cm
−2
. The enhanced electrocatalytic activity is due to the synergistic contribution of the sulfurized NiFe composite along with the meticulous oxygen-nitrogen co-functionalization. Additionally, the ASCD with the FNMOS positive electrode and the CFAC negative electrode achieves maximum energy density (ED) and power density (PD) values of 350 μW h cm
−2
(825 μW per cm
2
PD) and 7960 μW cm
−2
(200 μW h per cm
2
ED). Furthermore, the device demonstrated exceptional rate capability by maintaining over 96% of its initial capacity even after 25 000 cycles of charge and discharge. The exceptional stability was further characterized by the
ex situ
post-mortem analysis of the FNMOS electrode after the stability test. These encouraging electrochemical results, paired with some practical use cases, demonstrate the applicability of FNMOS as a next-generation energy storage material.
This study showcases a supercapacitor device with oxygen-nitrogen dual functionalized and sulfurized iron-nickel hydroxysulfide, demonstrating high performance and stability for energy storage.
•Ca13X was effective for dilute N2O adsorption.•Ca13X packed-bed DBD reactor was developed for cyclic removal of dilute N2O.•Cyclic operation was more energy-efficient than continuous ...operation.•Plasma-induced heat desorbed the adsorbed N2O, which was decomposed in gas phase.
Removal of dilute N2O from gas streams by a cyclic adsorption–decomposition using Ca13X (Ca2+ exchanged 13X) in combination with N2 nonthermal plasma was studied in this work. Zeolite 13X was found to be the best for N2O uptake among tested commercial zeolites including 4A, H-β and 13X. By modifying 13X with Ca2+ cation using ion-exchange method, the N2O adsorption capacity was greatly enhanced from ca. 3.5×10−6 to 80×10−6molgzeolite-1 due to the stronger interaction of N2O with Ca2+ cation than that with Na+ cation. Ca. 96% of N2O removal efficiency at a SIEeq (equivalent specific input energy) of 1116JL−1 was obtained under the cyclic operation of 60-min N2O adsorption (initial concentration: 510ppm, gas flow rate: 0.5Lmin−1) over Ca13X followed by 20-min plasma decomposition of adsorbed N2O in stationary N2 atmosphere. In comparison, a similar performance was reached at a relatively high SIE of 1700JL−1 as the reactor was operated under continuous plasma condition. The time period of plasma step and therefore the energy consumption could be reduced by properly circulating N2 gas in the reactor. Also, SIEeq was found to decrease with increasing the adsorption time, whereby ca. 95% of N2O removal efficiency could be achieved at a SIEeq of 298JL−1 as the adsorption time was 180min. The regeneration of N2O-adsorbed Ca13X by N2 plasma was initiated by plasma-induced desorption of adsorbed N2O followed by decomposing the desorbed N2O in plasma gas phase.
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