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[Display omitted] • The guest exchange in the sII (CH 4 + C 3 H 8) hydrate – (CO 2 + N 2) replacement was investigated. • CO 2 + N 2 mixtures with varying compositions and partial pressures of CO 2 were injected. • The extent of replacement and structural transition increased as the CO 2 composition and partial pressure increased. • The newly formed sI hydrates mainly consisted of CO 2 and N 2. • The guest exchange behavior in the sII small cages significantly affected the CO 2 /N 2 ratio in the replaced hydrates. In this study, the guest exchange behavior in the sII (CH 4 + C 3 H 8) hydrate – (CO 2 + N 2) replacement at various CO 2 concentrations was experimentally investigated to elucidate the influence of the structural transformation of the initial sII hydrate on the replacement efficiency at different feed gas compositions and injecting pressures. The extent of replacement, structural identification, and cage occupancy of guest molecules in the replaced hydrates were determined by a combination of gas chromatography (GC), powder X-ray diffraction (PXRD), and 13C NMR spectroscopy. The experimental results demonstrated that injecting feed gas with higher CO 2 concentrations (% CO2) at a higher partial pressure of CO 2 (P CO2) resulted in a higher weight fraction of sI hydrates (a greater degree of structural transformation from sII to sI) after replacement and consequently, higher replacement efficiency. The newly formed sI hydrates after replacement were primarily composed of CO 2 and N 2. The guest-inclusion behavior in the small (512) cages of the sII hydrates after replacement, as revealed by Rietveld refinement of the PXRD patterns, had a dominant influence on the total CO 2 /N 2 ratios in the replaced hydrates. The findings of this study offer valuable insights into the guest exchange mechanism occurring in sII hydrates during flue gas injection and can aid in estimating the optimal compositions of flue gas for energy recovery and CO 2 sequestration through guest replacement in natural gas hydrates. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effects of NaCl on thermodynamic and kinetic CO 2 selectivity were investigated. • The presence of NaCl enhanced thermodynamic CO 2 selectivity in CO 2 + N 2 hydrate. • The conversion into CO 2 + N 2 hydrate was lower in the NaCl solution system. • The kinetic CO 2 selectivity in the hydrate phase was more pronounced in the NaCl solution system. The importance of carbon capture and storage (CCS) has recently been emphasized owing to the ever-increasing global warming. Direct CO 2 sequestration in marine sediments is an attractive option for CO 2 storage, and some amount of injected CO 2 can be stored in the form of solid gas hydrates. In this study, the effects of NaCl on the hydrate phase equilibria, thermodynamic and kinetic CO 2 selectivity, and time-dependent growth behaviors of CO 2 + N 2 hydrates were experimentally investigated to elucidate their implications for hydrate-based CO 2 sequestration. The presence of NaCl shifted the equilibrium conditions of CO 2 + N 2 hydrates to the higher-pressure or lower-temperature region, whereas it increased thermodynamic CO 2 selectivity at a specified temperature and pressure, which was also confirmed by the pressure-composition diagram. As revealed by powder X-ray diffraction analysis, the conversion into CO 2 + N 2 hydrate was lower in the saline water system because of the lower initial driving force and gradual salt enrichment in the residual solution during hydrate growth. In situ Raman spectroscopic measurements demonstrated that CO 2 was kinetically selective at the early stage of CO 2 + N 2 hydrate formation and that kinetic CO 2 selectivity was more noticeable in the saline water system. The overall results provide an in-depth understanding of the role of salts in CO 2 + N 2 hydrate formation and thus offer valuable insights into hydrate-based CO 2 storage and geological CO 2 sequestration. [ABSTRACT FROM AUTHOR]

The aim of this study is to synthesize the three different hybrid materials precursor to natural biopolymer chitosan. The silanes viz., 3-mercaptopropyl trimethoxysilane, trimethoxy(octyl) silane and 3-aminopropyl triethoxysilane were grafted with the chitosan network and were named as CHMS, CHTS and CHAS, respectively. The materials were characterized by the FT-IR spectrometry, SEM–EDX and XPS analyses. These solids were then employed in the efficient removal of Cr(VI) from aqueous solutions using batch and column reactor operations. The functionalized biomaterials possessed extremely high percent removal of Cr(VI) compared to bare chitosan at wide pH range i.e., pH ∼3.0 to 8.0. A fast uptake of Cr(VI) was occurred and high percentage removal was obtained at wide range of Cr(VI) initial concentrations (7.7–100.58 mg/L). The equilibrium state sorption data were utilized for the Langmuir and Freundlich adsorption isotherm studies. Similarly, an increase in background electrolyte concentrations from 0.0001 to 0.05 mol/L NaNO 3 was assessed for the uptake of Cr(VI) by these hybrid materials. Relatively a fast uptake of Cr(VI) by these hybrid materials were obtained and further the time dependence data were fitted well to the pseudo-second-order and fractal-like pseudo-second-order kinetic models rather a pseudo-first-order kinetic model. Furthermore, a detailed sorption mechanism was included with the help of FT-IR, TOC and XPS analyses. In addition, CHMS and CHTS were used for dynamic studies under column reactor operations. The breakthrough curves were then used for the non-linear fitting of the Thomas equation and the loading capacity of the column for Cr(VI) were estimated. [ABSTRACT FROM AUTHOR]

The aim of this study is to synthesize novel hybrid porous materials using locally available clay and commercial bentonite and to assess their suitability in the attenuation of arsenic from ground water. Therefore, the clay samples are modified with hexadecylammonium bromide (HDTMA) or pillared with aluminium and then modified with HDTMA. The hybrid materials are characterized by the FT-IR, XRD and SEM analytical methods. Moreover, the BET (Brunauer–Emmett–Teller) specific surface area along with the pore diameter was obtained for these solids. Hybrid materials are then assessed in an effective and efficient remediation of aquatic environment contaminated with arsenic. Various physico-chemical parametric studies enable to deduce plausible mechanism involved at solid/solution interface. The sorptive pH (pH 2.0–10.0), concentrations (1.0–20.0 mg/L) and background electrolyte concentrations (0.001–0.1 mg L −1 NaNO 3 ) dependence sorption of As(III) and As(V) is studied by these solids. The sorption of As(III) or As(V) by these hybrid materials are further illustrated with the FT-IR analysis conducted for the arsenic loaded solids. Further, the simultaneous removal of phenol and arsenic is assessed and results show that the hybrid materials are useful in simultaneous remediation of water contaminated with phenol and, at least, As(V). The removal of arsenic is assessed separately in presence of several cations (Cd(II), Cu(II) and Mn(II)) and anions (glycine, iminodiacetic acid, ethylene diamine tetra acetic acid disodium salt, oxalic acid, phosphate and sulfate). [ABSTRACT FROM AUTHOR]

Highlights: [•] Tandem plasma-catalytic reactor with monolithic ceramic-supported catalysts. [•] Enhanced decomposition of acetone with moderate energy consumption. [•] Generation of far more reactive oxidant than ozone itself on MnO2 catalyst. [Copyright &y& Elsevier]

Highlights: [•] Atmospheric pressure plasma technique for RuO2 nanomaterials synthesis. [•] Substrate induced morphological variations. [•] Visible light photo-catalysis. [•] Shape dependent catalytic properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] Green treatment proposed using Ferrate(VI) in the remediation of Cu(II)-IDA and Zn(II)-IDA contaminated water. [•] Mineralization of IDA along with M(II) was removed simultaneously. [•] Kinetics of degradation was proposed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Novel manganese dioxide nano-particles immobilized on activated carbons. [•] Morphology of materials was obtained by SEM images. [•] Materials showed enhanced capacity in Cd(II) and Pb(II) removal. [•] Column reactor operations conducted for remediation. [Copyright &y& Elsevier]

Abstract: Natural mica type of clay mineral sericite was modified to obtain the materials viz., Al-HDTMA-sericite (AH) and Al-AMBA-sericite (AA) which was characterized by the FT-IR and XRD data and morphologically analyzed by the SEM images. Further, the simulated batch reactor data indicated that increase in sorptive concentration enhanced the uptake of these pollutants and the 1000 times increase in ionic strength i.e., background electrolyte concentration (NaNO3) caused an insignificant decrease in As(V) removal, which inferred that As(V) was adsorbed specifically onto the solid surface. However, it was affected greatly with As(III) pointed that As(III) was sorbed mainly through electrostatic or even with van der Waals attraction. pH dependence data showed that arsenic removal was greatly affected with change in solution pH. Simultaneous presence of phenol in the removal of As(III) or As(V) showed insignificant change in arsenic removal by these materials pointed that different sorption sites available for these two different contaminants. Results obtained under dynamic conditions inferred that materials were reasonably useful in the speciation/attenuation of these two metal ions from water bodies. The breakthrough data was fitted well to the Thomas equation and hence, the maximum amount of the As(III) or As(V) to be loaded was found to be 0.338 and 0.433mg/g respectively for AA and AH for As(III) and 0.541 and 0.852mg/g respectively for AA and AH for As(V) under the specified column reactor conditions. Comparing these two materials AH possessed with higher removal capacity than AA, at least, for these two contaminants. [Copyright &y& Elsevier]

Abstract: The aim of this investigation was to obtain iron-oxide nano-particles-immobilized sand (INS) by simple impregnation process. For the purpose, locally available sand was used with prior acid activation. The INS sample was characterized by XRD and SEM/EDX analytical methods. Further, the solid was employed for its possible implication in the removal of several toxic heavy metal ions viz., Cu(II), Cd(II) and Pb(II) from aqueous solutions under the static and dynamic experimental conditions. Batch experiments were carried out analyzing various physico-chemical parametric studies viz., effect of solution pH, ionic strength and sorptive concentration. The equilibrium state data obtained by concentration dependence study was utilized to obtain the Langmuir and Freundlich adsorption modeling. INS sample was also employed to assess the suitability of material in the removal of these heavy metal toxic ions under the dynamic conditions i.e., in column studies. The breakthrough data obtained by column studies were then utilized to model it with Thomas equation and hence, estimated the loading capacity of Cu(II)/or Cd(II)/or Pb(II) under the specified column conditions. Results obtained showed that INS is found to be one of promising and effective solid material and could be used in several wastewater treatment strategies in particular the treatment wastewaters contaminated with these heavy metal toxic ions. [Copyright &y& Elsevier]

Abstract: A dielectric barrier discharge (DBD) system employing wastewater as one of the electrodes was applied to the degradation of an azo dye, Orange II. The main advantage of this system is that reactive species like ozone and ultraviolet (UV) light produced by the DBD can be utilized for the treatment of wastewater. This system was able to remove the chromaticity and destroy the benzene and naphthalene rings in the dye molecule effectively. The results obtained under several conditions revealed that the UV emission from the DBD reactor could enhance the degradation of the dye, particularly in the presence of titanium oxide photocatalyst. The products resulting from the destruction of the rings in the dye molecule were found to be highly recalcitrant against further oxidation to smaller molecules. The change in the initial dye concentration showed that the reaction order was around 0.8 with respect to the dye concentration. The reduction in the concentration of total organic carbon was much more efficient with oxygen than with air. [Copyright &y& Elsevier]

Abstract: A two-stage process consisting of an ozonizing chamber and an absorber containing a reducing agent solution was proposed to remove nitrogen oxides (NO x ) from exhaust gas. In the ozonizing chamber where the exhaust gas is treated by ozone, NO (the main component of NO x ) was oxidized to NO2, and in the next step, NO2 was reduced to N2 by sodium sulfide (Na2S) used as the reducing agent. The NO x removal efficiency obtained by this two-stage process was higher than 95%. It was found that about three fourth of sodium sulfide was consumed without reacting with NO x , and accordingly the amount of sodium sulfide required should be four times that of NO x to be removed. The problem regarding the emission of H2S from Na2S was deeply related to the pH of the reducing agent solution, which could be solved by adjusting the pH using a basic reagent (NaOH). The concentrations of NO2 − and NO3 − in the reducing agent solution after processing were analyzed, which showed that about 25% of the NO x removed from the exhaust gas was simply dissolved in the reducing agent solution, i.e., about 75% of the NO x removed was reduced to N2. [Copyright &y& Elsevier]

Abstract: The behavior of the selective catalytic reduction of nitrogen oxides (NO x ) assisted by a dielectric barrier discharge was investigated. The principal function of the dielectric barrier discharge in the present system is to generate ozone, which is continuously fed to a chamber where the ozone and NO-rich exhaust gas (NO forms the large majority of NO x ) are mixed. In the ozonization chamber, a part of NO contained in the exhaust gas is oxidized to NO2, and then the mixture of NO and NO2 enters the catalytic reactor. The ozonization method proposed in this study was found to be more energy-efficient for the oxidation of NO to NO2 than the typical nonthermal plasma process. The degree of NO oxidation was approximately equal to the amount of ozone added to the exhaust gas, implying that the decomposition of ozone into molecular oxygen was relatively slow, compared to its reaction with NO. When the exhaust gas was first treated by ozone to produce a mixture of NO and NO2, a remarkable enhancement in the catalytic reduction of nitrogen oxides was observed. Neither NO3 nor N2O5 was formed in the present system, but small amounts of ozone and N2O (less than 5ppm) were detected in the outlet gas. [Copyright &y& Elsevier]

A positive pulsed corona discharge process was applied to the removal of sulfur dioxide and nitric oxide from a simulated flue gas stream, and a mathematical model was proposed to describe this process theoretically. The proposed model takes into account generation of radicals by pulsed corona discharge, followed by radical utilization for the removal of the pollutants. Radicals such as O, OH, N, H, etc. may be concerned in the removal of the pollutants. Their concentrations were derived by considering direct electron impact on the dissociation of gaseous molecules (O2, N2, H2O) and subsequent excitation transfer reactions of excited oxygen atoms to produce O and OH radicals. The effects of various operating parameters such as feed gas flow rate, initial concentration, oxygen content, humidity, peak voltage and pulse repetition rate on the removal were examined. So as to establish the validity of the model, the calculated results were compared with the experimental data. Although some discrepancy between the calculated and experimental results was observed at high pulse repetition rate, the proposed model was found to properly predict the experimental data on the whole. [Copyright &y& Elsevier]

• A cage-specific guest exchange during the CH 4 –CO 2 replacement was quantitatively observed. • A multi-methodological method was used to examine the time-dependent guest exchange behaviors. • The guest exchange in the large cages had a greater effect on the extent of replacement. • The replacement kinetics was faster at a higher PCO 2 because of the higher CO 2 occupancy in the large cages. CH 4 –CO 2 replacement in naturally occurring gas hydrates has been considered a promising method for both energy recovery and CO 2 sequestration. In this study, the time-dependent guest exchange behaviors and guest distributions during CH 4 –CO 2 replacement were closely examined at two different CO 2 injecting pressures (2.2 and 3.5 MPa) using nuclear magnetic resonance (NMR), in-situ Raman spectroscopy, powder X-ray diffraction (PXRD), and gas chromatography. The 13C NMR spectra confirmed that the cage occupancy ratio of the CH 4 molecules in the large 51262 and small 512 cages (θ L /θ S,CH4) after the replacement was significantly smaller than that before the replacement because of the preferential occupation of CO 2 in the large 51262 cages. The time-dependent Raman spectra revealed that the rate of CO 2 inclusion and the resultant CH 4 depletion in the hydrate phase during the replacement was faster at a higher CO 2 injecting pressure. The Rietveld refinement of the PXRD patterns offered a quantitative cage occupancy of CH 4 and CO 2 molecules before and after the replacement. The time-dependent cage occupancy values of CH 4 and CO 2 during the replacement obtained from a multi-methodological approach, which is a combination of PXRD analysis and in-situ Raman measurement, demonstrated that a significant guest exchange in the large 51262 cages had a greater effect on the extent of replacement and that the kinetics of the CH 4 –CO 2 replacement was accelerated at a higher CO 2 injecting pressure. The results provide a better understanding of the kinetics and mechanism of the cage-specific CH 4 –CO 2 replacement occurring in the sI hydrates for CH 4 recovery and CO 2 sequestration. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Clathrate growth kinetics and time-dependent CO 2 selectivity were investigated. • At the early stage of clathrate formation in pure water, CO 2 selectivity was higher. • Clathrate CO 2 composition was not changed during THF and TBAC clathrate formation. • CO 2 selectivity was dependent on both the kinetics and equilibrium of clathrates. Abstract Upgrading CO 2 -rich natural gas or biogas through CO 2 capture is essential to reduce greenhouse gas emissions and to increase its energy density. In this study, clathrate-based CO 2 capture from CO 2 -rich natural gas or biogas was investigated with a primary focus on kinetic CO 2 selectivity. The time-dependent CO 2 selectivity during clathrate formation for pure water, tetrahydrofuran (THF, 5.6 mol%) solution, and tetra-n-butylammonium chloride (TBAC, 3.3 mol%) solution was examined through direct composition analysis and in situ Raman spectroscopy. In pure water, the CO 2 composition in the clathrate phase was much higher at the early stage of clathrate formation than that at equilibrium, indicating that CO 2 is kinetically and thermodynamically selective. For both the THF (5.6 mol%) and TBAC (3.3 mol%) solutions, the CO 2 composition in the clathrate phase was almost constant during clathrate formation. However, the TBAC (3.3 mol%) solution showed significantly higher CO 2 composition (∼74%) throughout the reaction, whereas the THF (5.6 mol%) solution exhibited enrichment of CH 4 in the clathrate phase. The experimental results clearly demonstrate that CO 2 selectivity is dependent on both kinetics and equilibrium of clathrate hydrates and that the addition of thermodynamic promoters, such as THF and TBAC, can affect kinetic CO 2 selectivity as well as equilibrium CO 2 selectivity in the clathrate phase. [ABSTRACT FROM AUTHOR]

Highlights • Thermodynamic and kinetic influences of NaCl on HFC-125a hydrate were investigated. • NaCl enrichment in the unconverted solution resulted in a lower conversion. • The presence of NaCl had little effect on the Δ H of HFC-125a hydrate. • The hydrate dissociation was retarded due to the formation of NaCl⋅2H 2 O. Abstract In this study, HFC-125a was selected as a hydrate-forming guest for gas hydrate-based desalination. The thermodynamic and kinetic effects of NaCl on HFC-125a hydrates were investigated with a primary focus on phase equilibria, gas uptake, dissociation enthalpy, and dissociation behavior. The equilibrium curve of HFC-125a hydrate shifted to higher pressure regions at any given temperature depending on the concentration of NaCl. The presence of NaCl also reduced the gas uptake and conversion to hydrates, because of the enrichment of NaCl in the solution during gas-hydrate formation. Even though NaCl did not affect the dissociation enthalpy of the HFC-125a hydrate, the thermograms obtained using a high-pressure micro-differential scanning calorimeter (HP μ-DSC) demonstrated that HFC-125a + NaCl hydrates started to dissociate at lower temperatures due to NaCl in unconverted solutions. Rietveld refinement of powder X-ray diffraction (PXRD) patterns indicated that the HFC-125a hydrate (sII) was transformed into Ih as it dissociated. The dissociation of HFC-125a + NaCl hydrates was retarded and completely ended at higher temperatures compared to the pure HFC-125a hydrate by the sodium chloride dihydrate (NaCl⋅2H 2 O). Overall, these results could facilitate a better understanding of HFC-125a hydrates in the presence of NaCl; further, they might also be useful in the design and operation of hydrate-based desalination plants using HFC-125a. [ABSTRACT FROM AUTHOR]

Removal of dilute N 2 O from gas streams by a cyclic adsorption–decomposition using Ca13X (Ca 2+ exchanged 13X) in combination with N 2 nonthermal plasma was studied in this work. Zeolite 13X was found to be the best for N 2 O uptake among tested commercial zeolites including 4A, H-β and 13X. By modifying 13X with Ca 2+ cation using ion-exchange method, the N 2 O adsorption capacity was greatly enhanced from ca. 3.5 × 10 −6 to 80 × 10 −6 mol g zeolite - 1 due to the stronger interaction of N 2 O with Ca 2+ cation than that with Na + cation. Ca. 96% of N 2 O removal efficiency at a SIE eq (equivalent specific input energy) of 1116 J L −1 was obtained under the cyclic operation of 60-min N 2 O adsorption (initial concentration: 510 ppm, gas flow rate: 0.5 L min −1 ) over Ca13X followed by 20-min plasma decomposition of adsorbed N 2 O in stationary N 2 atmosphere. In comparison, a similar performance was reached at a relatively high SIE of 1700 J L −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 N 2 gas in the reactor. Also, SIE eq was found to decrease with increasing the adsorption time, whereby ca. 95% of N 2 O removal efficiency could be achieved at a SIE eq of 298 J L −1 as the adsorption time was 180 min. The regeneration of N 2 O-adsorbed Ca13X by N 2 plasma was initiated by plasma-induced desorption of adsorbed N 2 O followed by decomposing the desorbed N 2 O in plasma gas phase. [ABSTRACT FROM AUTHOR]

The present communication addresses the development of a novel hybrid material precursor to natural sericite. The hybrid material is then successfully utilized for efficient removal of cadmium and phenol from aqueous solutions. Initially, sericite was annealed and activated with hydrochloric acid. The activation caused a significant increase in specific surface area of sericite, thereby provided a suitable surface structure for grafting of organosilanes. The activated sericite (AS) was functionalized with 3-aminopropyltriethoxysilane (APTES), and the resultant AS-APTES along with pristine sericite and AS were characterized using SEM–EDX, BET, XRD and FT-IR analyses. Batch reactor studies showed that increase in sorptive pH, contact time, initial concentration and temperature significantly favored the sorption of Cd(II), and a 100-fold increase in background electrolyte concentration did not significantly affect the uptake of Cd(II) or phenol from aqueous solutions. Cd(II) removal was found to be spontaneous and the uptake process was endothermic in nature. Further, the intra-particle diffusion was found to be the rate-limiting step in the sorption of Cd(II). Various physico-chemical parametric studies enabled to discuss the sorption mechanism of these contaminants at the solid/solution interface. In a single pollutant sorption studies, it was deduced that the Cd(II) was forming an inner-sphere complexes, whereas phenol was sorbed through the hydrogen bonding with the amino groups or partitioned within the interspace region. Simultaneous sorption studies suggested that these two pollutants were possibly removed simultaneously by the prevailing hydrophilic and hydrophobic groups. Furthermore, desorption and reusability studies as well as the applicability of the material for real wastewater treatment demonstrated that AS-APTES is a promising solid material for the efficient removal of two important water pollutants i.e., Cd(II) and phenol from aqueous waste. [ABSTRACT FROM AUTHOR]

[Display omitted] • EMCH-TFA additive improves the film morphology and passivates defects. • The addition of EMCH-TFA suppresses the formation of the small n phase. • The quasi-2D PeLED yields an EQE of 19.77 % and a current efficiency of 66.7 cd/A. • EMCH-TFA-treated MAPbI 3 -based PeSCs exhibits improved performance. Due to their unique quantum confinement, dielectric coupling, and tunable high-efficiency electroluminescence, quasi-two-dimensional (quasi-2D) perovskite light-emitting diodes (PeLEDs) have attracted considerable attention. However, imperfections in perovskite thin films introduced during the solution-based fabrication process lead to significant non-radiative recombination, hindering device performance. Addressing this challenge is crucial for realizing high-performance quasi-2D PeLEDs. In this study, we introduce an ion-pairing-type additive, 6-maleimidohexanehydrazide trifluoroacetate (EMCH-TFA), designed to cooperatively passivate defects in quasi-2D perovskites. The diverse functional groups (–COOH, –NH 2 , -CF 3) on EMCH-TFA could provide disparate modification to perovskite, among which the C O group tends to coordinate with the uncoordinated Pb2+ ions, thereby passivating the defects in the perovskite crystal. Additionally, the –NH 2 and -CF 3 groups establish hydrogen bonds with Br- ions and BA+ spacer cations, respectively. This multifaceted approach suppresses the formation of the small n phase and induces alterations in the crystalline state by interacting with numerous sites in perovskites, including A', B, and X sites. Consequently, the quasi-2D PeLED based on BA 2 Cs n-1 Pb n Br 3n+1 exhibits enhanced brightness, achieving a current efficiency of 66.7 cd/A and an impressive external quantum efficiency of 19.77 %. [ABSTRACT FROM AUTHOR]

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 (SO 4 2 − , NO 3 − and NH 4 + ) 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 SO 4 2 − 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 NH 4 + and NO 3 − 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. [ABSTRACT FROM AUTHOR]

[Display omitted] • A practice-scale sandwich-type honeycomb catalyst discharge reactor was developed. • High-throughput without significant pressure drop condition was obtained. • 94.5 % IPA was removed using the honeycomb catalyst discharge reactor. • Uniform discharge was created using Pd/Al2O3/honeycomb combined with plasma. • Byproducts formation and IPA oxidation pathways were elucidated. A practical-scale sandwich-type honeycomb catalyst reactor incorporating non-thermal plasma was developed for the high-throughput removal of isopropanol (IPA) from air. The Pd/γ-Al 2 O 3 /honeycomb catalyst was fabricated by coating a cordierite monolith with γ-alumina powder on which to support the palladium (Pd). The supported catalyst showed good activity and the combination of the honeycomb structure with plasma produced a uniform plasma inside the catalyst chamber. The influence of different parameters, including the energy density (SIE), humidity, initial concentration, and flow rate, on the plasma characteristics and IPA removal efficiency was investigated. The results showed that the SIE has the strongest effect on the IPA removal efficiency. The efficiency of IPA removal was 94.5% and the CO2 selectivity was 85% for an SIE of 180 J/L. Using optical emission spectroscopy, we found that the increased formation of atomic oxygen and reactive species plays an essential role in the oxidation of IPA by plasma catalysis. The main byproducts were identified by GC-MS, which indicated that acetone is the major liquid product. A plausible reaction mechanism for the plasma-catalytic oxidation of IPA is proposed based on the intermediates and byproducts. [ABSTRACT FROM AUTHOR]

Abstract: This work investigated the degradation of antibiotics in synthetically prepared wastewater by using dielectric barrier discharge (DBD) plasma. The veterinary antibiotics investigated include lincomycin, ciprofloxacin, enrofloxacin, chlortetracycline, oxytetracycline, sulfathiazole, sulfamethoxazole, sulfamethazine and trimethoprim. The effect of discharge power, initial concentration, working gas type (air or O2) and working gas flow rate on the degradation was examined and discussed. The experimental results indicated that the antibiotics were easily degraded by the DBD plasma and the degradation rates were mainly governed by the amount of the delivered energy. The degradation of the antibiotics followed an exponential decay with respect to the delivered energy. Each antibiotic substance was found to show a different degradability. On the basis of an initial concentration of 5mgL−1, the energy requirements for 60% degradation efficiency were in the range of 0.26–1.49kJmg−1, depending on the type of antibiotic substance, while those for 90% degradation efficiency ranged from 0.39 to 2.06kJmg−1. The DBD process proposed in this work may be a promising method for effectively degrading veterinary antibiotics. [Copyright &y& Elsevier]

[Display omitted] • A dual-sensitive 1D PC was developed for use in encryptable anticounterfeiting films. • The PC showed humidity-sensitive color responses that can be tuned by UV irradiation. • The humidity sensitivity of the PC was decreased when exposed to aldehydes. • The aldehyde exposed PC could be recovered to its pristine by immersing it in HCl. • The prepared PC-based anticounterfeiting film was suitable for high-level security. Although considerable progress has been made in anticounterfeiting film technologies, developing difficult-to-imitate novel anticounterfeiting films is still challenging. Herein, we report novel photopatternable one-dimensional photonic crystal (1D PC)-based anticounterfeiting films, whose colors can be changed by human breath and which can be encrypted and decrypted using small aldehydes and hydrochloric acid, respectively. A photo-crosslinkable TiO 2 –copolymer hybrid (Ti70) and primary-amine-containing copolymer (P(AEMA 97 - co -BPA 3)–NH 2) were prepared and utilized to fabricate 11-layered 1D PC (TiNH 2 PC). In addition, using UV post-treatment with customized photomasks, TiNH 2 PCs with hidden photopatterns that showed tunable humidity-responsive bright color contrast could be fabricated. However, after exposure to aldehydes, the TiNH 2 PC showed reduced or no color shifts in response to further changes in the relative humidity. This is because the hydrophilicity of the P(AEMA 97 - co -BPA 3)–NH 2 layers decreased when they converted to P(AEMA 97 - co -BPA 3)-imine layers under aldehyde exposure. However, the aldehyde-exposed TiNH 2 PC could be reversibly recycled to its pristine state by simply immersing it in a hydrochloric acid solution (1 M) for 30 min. These findings provide insights into fabricating various colorimetric sensors as non-imitable anticounterfeiting films with selective encryption/decryption for achieving forensic-level security. [ABSTRACT FROM AUTHOR]

[Display omitted] • In-plasma is superior to injected-plasma catalysis for NO x removal at low temperatures. • Significant synergy between plasma and catalyst for NO x removal at low temperatures. • NO x removal efficiency up to 70% by assisting plasma at [200–250 °C] temperature. • Energy delivery through plasma is better than a thermal process for NO x removal. • Injected-plasma catalysis has potential applications in circumstantial high-throughput gas. Plasma-assisted hydrocarbon selective catalytic reduction (HC-SCR) of NO x was investigated by a packed Ag/γ-Al 2 O 3 catalyst in a dielectric barrier discharge reactor at low temperatures. The effect of plasma discharge on NO x removal was investigated with two methods for comparison, in- and injected-plasma catalysis systems. In-plasma catalysis comprised a plasma-catalytic discharge with the entire feed gas, and injected-plasma catalysis incorporated a part of feed gas consisting of dodecane pretreated with the plasma-catalytic discharge and mixed with the remaining gas before passing through the catalyst-alone stage. Here, using the surface response method with temperature and specific energy input (SEI) as independent variables, the results revealed that energy delivery through plasma gained more NO x removal efficiency than that by thermal catalyst process; a set of SEI and temperature is needed to obtain a similar level of NO x removal. There is a significant synergy between plasma and catalyst in in-plasma catalysis at low temperatures (≤250 °C) that increased NO x removal efficiency up to Δη = 50% (SEI = 137 J/L; T = 200 °C). In-plasma catalysis is superior to injected-plasma catalysis for enhancing the NO x removal and widening the temperature window of effective NO x removal owing to the plasma-catalytic interface in-plasma catalysis supplies. Interestingly, the results also revealed that the plasma in the catalyst for both methods did not always improve the NO x removal efficiency. The plasma had a negative effect on NO x removal at sufficient temperature and SEI. As a result, the in-plasma catalysis presented a high NO x removal efficiency; it can be higher than 70% at temperatures of 200–250 °C. However, injected-plasma catalysis has potential applications in circumstantial high-throughput gas due to low plasma energy consumption by adjusting the entire feed to plasma-treated gas ratio. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel copolymer–TiO 2 hybrid 1D PC sensor was developed for detection of adulterated diesel. • Multilayered hybrid 1D PC showed tunable reflection colors when immersed in C 6 –C 16 n-alkanes. • 1D PC exhibited excellent recyclability during repeated swelling/deswelling test. • Pure diesel and adulterated diesel were discriminated by reflection colors of 1D PC. Diesel fuel, which is widely used in engines, generators, and industrial equipment, is often adulterated with kerosene. The use of adulterated diesel fuel reduces the performance and durability of diesel–fuel-powered engines, causes environmental pollution, and promotes tax evasion. However, detecting kerosene in diesel using a high-precision instrumental technique such as gas chromatography with flame ionization detection is difficult because both diesel and kerosene contain C 6 –C 16 paraffins. In this study, we developed a simple and reliable colorimetric sensor to detect various volumetric fractions of kerosene in diesel. A novel 15-layered one-dimensional photonic crystal (1D PC) was prepared using a photo-crosslinked butyl acrylate (BA)–based copolymer [P(BA- co -BPA)] as the low-refractive-index material and a photo-crosslinked copolymer–TiO 2 hybrid (Ti70) as the high-refractive-index material. The P(BA- co -BPA) layers swelled to a greater extent in smaller-sized C 6 –C 16 n -alkanes than in the larger ones. Consequently, the reflection colors of P(BA-co-BPA)/Ti70 PC underwent a greater red shift from the sky-blue color of the pristine state as the swelling increased from the C 16 to the C 6 n -alkanes. When immersed in pure diesel, the 1D PC exhibited a green color, which underwent a greater red shift as the volume fraction of kerosene increased from 10% (∼limit of colorimetric detection) to 100% in the kerosene + diesel mixtures. The 1D PC reached saturation within 45 min and changed color from the sky-blue corresponding to the pristine state to greenish yellow, yellow, yellow-orange, orange, and reddish orange in 10%, 20%, 30%, 50–70%, and 100% kerosene, respectively. Moreover, it exhibited recyclability in five swelling/deswelling cycles in diesel and kerosene. We expect that these findings will promote the development of simple and state-of-the-art 1D PC sensors. [ABSTRACT FROM AUTHOR]

The aim of this study was to obtain indigenously the mesoporous silica (AMS) precursor to 3-aminopropyltriethoxysilane (APTES) and utilizing chitosan a templating natural biopolymer. The textural characteristics of AMS were obtained by the SEM (Scanning Electron Microscopy) and BET (Brunauer–Emmett–Teller) surface area measurements. AMS solid possessed specific surface area of 511.77 m 2 /g and having pore size and pore volume of 3.38 nm and 0.036 cm 3 /g, respectively. Further, the AMS was characterized by the XRD (X-ray Diffraction) and FT-IR (Fourier Transform- Infra Red) analyses. The mesoporous silica was employed for efficient removal of cadmium(II) and lead(II) from aqueous solutions. The influence of solution pH, initial cadmium(II)/or lead(II) concentrations, contact time, and background electrolyte concentrations were studied to deduce the mechanism involved at solid/solution interface. The equilibrium state adsorption data were utilized for the Langmuir and Freundlich adsorption isotherms and the Langmuir adsorption isotherm showed a good agreement with the experimental data. Uptake was found to be fairly fast and the kinetic modelling suggested that the adsorption of cadmium(II)/or lead(II) by AMS was occurred through fractal-like pseudo-second order kinetics. An increase in background electrolyte concentrations from 0.0001 to 0.01 mol/L NaNO 3 did not affect the removal of lead(II), whereas the cadmium(II) removal was slightly suppressed. The XPS (X-ray Photoelectron Spectroscopy) analysis indicated that removal of cadmium(II) or lead(II) occurred through the formation of a chemical bond with the oxygen atoms present with AMS solid. Furthermore, fixed-bed column adsorption was conducted and the loading capacity of cadmium(II) and lead(II) was found to be 11.54 and 8.59 mg/g, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Stable plasma generation in reactor configuration comprising multiple honeycomb monoliths. • Linear relationship between discharge power and increased number of monoliths. • High ethylene adsorption capacity in an open channeled monolith catalyst at humid conditions. • Higher ethylene removal efficiency with high energy yield at low energy requirement. • Simplified overall system and operation at atmospheric conditions. Dilute ethylene (C 2 H 4) was removed in a novel plasma reactor comprising multiple honeycomb monoliths consisting of up to four PdO/ZSM-5/monolith catalysts. These monoliths were packed in a tubular reactor separated by mesh electrodes alternatively grounded or connected to a high voltage (HV) power source. The effect of the number of monoliths on the discharge power, adsorption, and removal of C 2 H 4 was investigated. Additionally, the influence of the energy input, C 2 H 4 inlet concentration, and gas flow rate on the C 2 H 4 abatement was examined. The adsorption capacity, C 2 H 4 conversion, and energy efficiency were observed to increase as the number of monoliths increased. The effect of the palladium (Pd) loading technique, namely ion exchange (IE), incipient wetness impregnation (IM), and combined IE-IM, IE followed by IM, on the C 2 H 4 adsorption was also studied. The combined IE-IM method presented an exceptional adsorption capacity of ∼136 µmol/g catalyst under humid conditions despite nonpolar nature of C 2 H 4. C 2 H 4 removal was performed via both continuous and cycled storage-discharge (CSD) plasma-catalytic oxidation processes. The CSD process was conducted in two ways: with intermittent C 2 H 4 feed (CSD-IEF) and with maintained C 2 H 4 feed (CSD-MEF), both comprising intermittent plasma discharge. Intriguingly, the performance of the CSD-MEF process was superior (56 J/L, 1.61 g/kWh) to that of the CSD-IEF (119 J/L, 0.98 g/kWh), and continuous process (∼228 J/L, 0.53 g/kWh) in terms of energy efficiency as well as the overall simplicity of the system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Poly(iminoarylene)s through Buchwald-Hartwig reaction. • Hole injection polymers with thermally cross-linkable benzocyclobutene groups. • Excellent solvent resistance over 99 % after annealing at 150 °C for 40 min. • Better hole injection properties in the fabricated OLEDs than PEDOT:PSS. A cross-linkable poly(iminoarylene), poly[(9,9-dioctyl-N-(p-tolyl)-9H-fluoren-2-amine) –co- (9,9-bis(4-(bicyclo[4.2.0]octa-1(6),2,4-trien-7-yloxy)phenyl)-N-(p-tolyl)-9H-fluoren-2-amine)] [poly(FA -co- BFA)], was synthesized as a hole injection layer (HIL) for solution-processed organic light-emitting diodes (OLEDs). Poly(FA 90 - co -BFA 10) containing 10 mol% of benzocyclobutene (BCB) which is a thermally curable functional group was used in this study. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of poly(FA 90 -co- BFA 10) were measured to be −5.14 and −2.31 eV, respectively. After heating at 150 °C for 40 min, the spin-cast poly(FA 90 -co- BFA 10) film became completely crosslinked without requiring the use of additional initiators. The crosslinked thin film showed good film-forming properties and excellent solvent resistance (up to 99 %). A photo-crosslinked poly[bis(4-butypheny)-bis(phenyl)benzidine] (poly-TPD) was used as the hole-transporting layer (HTL) on top of the crosslinked poly(FA 90 -co- BFA 10). Finally, a solution-processed red phosphorescent OLED device with the structure of indium tin oxide/poly(FA 90 -co- BFA 10)/poly-TPD/emissive layer/TPBi/LiF/Al was fabricated and characterized. The device showed a low turn-on voltage (V on) of 3.5 V, a reasonably high current efficiency (CE) of 16.6 cd/A, and an external quantum efficiency (EQE) of 12.5 %, which are better than those of the corresponding reference device using PEDOT:PSS as the HIL. Moreover, the device fabricated using the poly(FA 90 -co- BFA 10) HIL demonstrated a longer lifetime than that fabricated using PEDOT:PSS. [ABSTRACT FROM AUTHOR]

Combined removal of n-heptane and CO using a catalytic reactor coupled with dielectric barrier discharge plasma was investigated over several metal oxide catalysts including bare γ-Al 2 O 3 , Ag 2 O/γ-Al 2 O 3 , MnO/γ-Al 2 O 3 , RuO 2 /γ-Al 2 O 3 and PdO/γ-Al 2 O 3 . In order to effectively utilize the heat generated during plasma discharge for enhancing catalytic reactions, the plasma-catalytic reactor was thermally insulated by covering it with a glass wool jacket. Plasma propagated radially outward from the central high-voltage electrode with gradually increasing the applied voltage, and the temperature decreased with the radial distance due to the decreased plasma intensity, exhibiting a volcanic temperature distribution. The increased reactor temperature could improve the removal of CO and the selectivity toward CO 2 . The results obtained from separate experiments of n-heptane and CO removal showed that the PdO/γ-Al 2 O 3 was the best for the simultaneous removal purpose. The effects of specific input energy ( SIE ), oxygen content, reaction temperature and PdO loading on the simultaneous removal of n-heptane and CO and the formation of byproducts were examined. The removal efficiencies of n-heptane obtained with different catalysts were similar to one another, whereas the removal of CO strongly depended on the type of catalyst. The catalytic activity for the oxidation of CO followed the order: MnO/γ-Al 2 O 3 < Ag 2 O/γ-Al 2 O 3 < RuO 2 /γ-Al 2 O 3 < PdO/γ-Al 2 O 3 . In the present plasma-catalytic hybrid reactor, the mixture of n-heptane and CO was mainly converted into CO 2 , and under an optimized condition, the selectivity toward CO 2 reached 100%. [ABSTRACT FROM AUTHOR]

This paper presents a facile method to fabricate the hole injection layer (HIL) for organic photovoltaic cells (OPVs) and organic light-emitting diodes (OLEDs) using a thermally annealed (NH 4 ) 2 WS 4 precursor under air ambient. The thermal gravimetric analysis curve shows that WS 3 , WS 2 , and WO x are formed by the thermal decomposition of (NH 4 ) 2 WS 4 above 160 °C. The disappearance of the S 2p peak in the photoemission spectra and of the W–S peak in the Raman spectra as well as the decrease in the water contact angle after annealing at 250 °C suggest that (NH 4 ) 2 WS 4 decomposed into WO x . The power conversion efficiency (PCE) of the OPV improved from 1.51% to 3.14% after the insertion of 250 °C-annealed (NH 4 ) 2 WS 4 as the HIL, which is comparable to the PCE of the OPV based on poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) HIL (3.23%). Furthermore, the luminance efficiency of the OLED with 250 °C-annealed (NH 4 ) 2 WS 4 (15.76 cd/A) was higher than that of the device based on PEDOT:PSS (12.34 cd/A). The results of the in situ deposition experiments revealed that the improved device performance originates from the energy level alignment and electron–hole balance. These data demonstrate that 250 °C-annealed (NH 4 ) 2 WS 4 is a promising candidate for fabrication of the HIL in optoelectronic devices using a facile solution process under air ambient. [ABSTRACT FROM AUTHOR]

Nanopillars-TiO 2 was immobilized onto a borosilicate glass disk using sol–gel template method. The TiO 2 film was immobilized with and without polyethylene glycol as filler media and annealed at 500 °C. The prepared films were characterized by the IR, XRD, XRF and XPS analytical methods. The surface morphology was obtained using FE-SEM and AFM images of these thin films and the BET specific surface area was obtained. Further, the Nanopillars TiO 2 was employed in the photocatalytic degradation of micro-pollutants viz ., diclofenac sodium and tetracycline hydrochloride from aqueous solutions using UV-light under batch reactor operations. Various physico-chemical parametric studies viz ., effect of pH, pollutant concentration and interfering ions was studied to deduce the mechanism involved in photocatalytic degradation of these pollutants. The time dependence degradation of these pollutants provided kinetics of degradation of these pollutants from aqueous solutions. The studies were further extended with total organic carbon measurement using TOC analyser to demonstrate an apparent mineralization of these pollutants. The photocatalytic degradation was assessed in presence of scavengers and several co-existing ions to simulate the data for real wastewater matrix. The hydroxyl radical scavengers 2-propanol and sodium bicarbonate greatly suppressed the catalytic activity of the thin films. However, the singlet oxygen scavenger sodium azide could not affect significantly the catalytic activity of these thin films at least the degradation of diclofenac sodium and tetracycline from aqueous solutions. [ABSTRACT FROM AUTHOR]

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 −27 mV. 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. [ABSTRACT FROM AUTHOR]

Highlights: [•] Large gas–liquid interfacial area and instant transfer of reactive species to water. [•] Effective decomposition of taste-and-odor compounds and cyanobacteria algae. [•] Good correlation of the decomposition efficiency to the specific energy input. [Copyright &y& Elsevier]

Highlights: [•] Attainment of spherical and sheet like RuO2 nanomaterials. [•] Physical and chemical characterization. [•] Shape dependent antibacterial activity. [Copyright &y& Elsevier]

Abstract: A highly porous SIMFUEL particle is prepared here for use as a feed material for electrochemical reduction. The prepared particles were found to have highly porous and sintered structure. The particles were electrolyzed in a LiCl-1wt.% Li2O melt at 650°C. A steel basket containing the particles and a platinum plate were used as a cathode and an anode, respectively. The analysis result reveals the reduction extent of uranium oxide to be in excess of 99%. The rare earth oxides were reduced to their metallic form in the range of 46–78%. The highly porous structure of the SIMFUEL particles is advantageous to speed up the electrochemical reduction process for pyroprocessing. [Copyright &y& Elsevier]

Abstract: The present communication aims towards the possible exploitation of modified natural sand materials in the remediation of the heavy metal toxic ions contaminated aquatic environment. The surface of the sand was modified as depositing the nano-particles of manganese (i.e., manganese-modified natural sand: MMNS) and the mineral phase of manganese was perhaps depicted to be pyrolusite as indicated by the XRD analytical data. The d-spacings of quartz was significantly enhanced with the manganese modification indicated the manganese caused an apparent increase in basal spacing of sand structure. SEM images and the EDX analysis showed that manganese nano-particles are evenly distributed onto the surface of sand. The BET surface area of the MMNS was increased significantly. The amount of manganese aggregated was found to be 1002.6mg/Kg of sand and the stability tests suggested that the nano-particles aggregated onto the sand surface are fairly stable within the pH region 3–10. Further, the removal behavior of this MMNS was employed for the attenuation of two important heavy metal toxic ions i.e., Pb(II) and Cu(II) in aqueous medium. The uptake of these two metal ions followed the Freundlich adsorption isotherm. The removal capacity of MMNS estimated with the Freundlich approximation was found to be 0.4596mg/g for Cu(II) and 2.996mg/g for Pb(II). Further, the 1000 times increase in ionic strength caused for relatively insignificant change in uptake of these two ions onto the solid surface points it a predominant strong chemical binding involved at the solid/solution interface. The column experiments and the breakthrough curves suggested that material possessed significantly high removal capacity i.e., 0.190 and 0.895mg/g, respectively, for Cu(II) and Pb(II) even under the dynamic conditions. [Copyright &y& Elsevier]

[Display omitted] • Kinetic guest exchange in sII hydrate-flue gas replacement was investigated. • The sII hydrate-flue gas replacement occurred iso-structurally. • The higher pressure enhanced guest exchange with CO 2 in both small and large cages. • The competitive inclusion of CO 2 and N 2 in the small (512) cages was observed. • The size and dispersive movement of the guest molecules affected the lattice parameter. In this study, the kinetics of guest exchange in sII (CH 4 (90%) + C 3 H 8 (10%)) hydrate – flue gas (CO 2 (20%) + N 2 (80%)) replacement was investigated to elucidate the replacement mechanism and guest exchange characteristics for hydrocarbon recovery and CO 2 sequestration. The Rietveld refinement of Powder X-ray diffraction (PXRD) patterns of the replaced hydrates at two pressures (11.0 MPa and 17.0 MPa) demonstrated that sII hydrate – flue gas replacement occurred iso-structurally. The time-dependent guest compositions in the hydrate phase and the cage occupancy of guest molecules were examined to understand the effect of pressure on guest exchange behaviors. The increased CO 2 inclusion in both the small (512) and large (51264) cages at a higher pressure resulted in the larger production of CH 4 and C 3 H 8 and a lower N 2 /CO 2 ratio in the hydrate phase. The slower inclusion rate and lower N 2 occupancy in the small (512) cages at a higher pressure during replacement were observed due to the competitive inclusion of CO 2 and N 2 in the small (512) cages. The molecular dynamics (MD) simulation demonstrated that the expansion or shrinkage of hydrate cages caused by guest exchange has a significant impact on the lattice parameter of the replaced hydrates and it was influenced by not only the average molecular size of guest molecules in each cage but also the dispersive movement of the guest molecules in each cage. [ABSTRACT FROM AUTHOR]

• A plasma reactor for practical-scale environmental plasma applications. • Successful plasma generation in a commercial honeycomb monolith. • Increased volume of plasma discharge with humidified air at high flow rates. Large-volume atmospheric-pressure plasma based on corona discharge was successfully generated in a sandwich-type plasma reactor by controlling the humidity of the feed gas. The reactor comprised a 5-cm-high and 9-cm-wide commercial honeycomb monolith and two perforated stainless-steel disk electrodes with 3-mm holes, which covered up both sides of the monolith. The high-voltage applied disk electrode was placed 2 ~ 6 mm away from the monolith, whereas the counter ground electrode typically touched it. The characteristics of air plasma such as power delivery, breakdown voltage, current, and impedance were found to strongly depend on the water vapor content in the feed gas as well as in the monolith, exhibiting an exponential increase of discharge power with increasing the humidity. The discharge characteristics also depended on the gas flow rate and the electrode-monolith distance. Better discharge performance was observed as the electrode was closer to the monolith, and as the air flow rate was higher. Discharge power above 30 W was achieved under the condition of gas flow rate 75 L/min, applied voltage 25 kV, and humidity 2.1%(v/v) when the high-voltage electrode was 2 mm away from the monolith, and the ground electrode kept up against it. The air plasma produced reactive species, being demonstrated by the formation of ozone at several tens of ppm, depending on specific energy input. The plasma source has potential applications in the abatements of odor, organic compounds, and NO x with high throughputs. [ABSTRACT FROM AUTHOR]

• 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-Al 2 O 3 were employed. This non-catalytic reaction system could successfully activate C H 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. [ABSTRACT FROM AUTHOR]