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The study investigates the effect of different parameters for the removal of SO 2 and NO x through a wet process concurrently. Two separate processes have been compared for the removal of flue gases, that is, Ozone/UV and H 2 O 2 /UV. The research aims to develop a comparative study for the removal of SO 2 and NO x simultaneously using Ozone/H 2 O 2 and UV light and find the energy consumption (also known as E EO ) for each process. Combining UV with O 3 and H 2 O 2 play a crucial role in generating hydroxyl radicals. Different combinations of Ozone/H 2 O 2 , flue gas, and UV intensity were studied at different pH and temperatures of the solution to achieve maximum removal of the flue gases. For, the ozonation process it was observed that the removal% of flue gases increases with increasing UV intensity, and at higher UV intensity (250 W), the removal% for NO x is 92% and SO 2 is 95% simultaneously at optimum temperature 308 K. For H 2 O 2 /UV process (250 W UV intensity), removal% for NO x is 95% and SO 2 is 100% at 313 K, 0.3 LPM flow rate of flue gases. The E EO values obtained for both processes were less than 1 for 95% NO x /SO 2 removal efficiency.

This article reports an alternative method for preparing nitrones using a tetrahedral capsule as a nanoreactor in water. Using the hydrophobic cavity of the capsule allowed us to reduce the reaction times and easily separate the nitrones from the reaction mixture, obtaining reaction yields equal or comparable to those obtained with the methods already reported. Furthermore, at the basis of this methodology, there is an eco-friendly approach carried out that can certainly be extended to other synthesis methods for the preparation of other substrates by exploiting various types of macrocyclic hosts, suitably designed and widely used in supramolecular chemistry.

As one of the main air pollutants, nitrogen oxides (NOx) have serious effects on human health and the environment. In our previous study, we found that Mn-MOF-74 shows excellent catalytic performance for the selective catalytic reduction (SCR) reaction with NH3 being the reductant (NH3-SCR) at low temperature. To obtain a further understanding of the NH3-SCR mechanism in Mn-MOF-74, in this paper, we investigated two important parts of the NH3-SCR process in Mn-MOF-74 using the density functional theory (DFT) method. On the one hand, the structural characteristics of two types of oxygen vacancies of Mn-MOF-74, namely carboxyl oxygen vacancies and hydroxyl oxygen vacancies, and their adsorption properties to reaction species were calculated. It was found that the oxygen vacancies not only activate the reaction species, but also promote the desorption of NO2 molecules from metal sites for the subsequent rapid SCR reactions. On the other hand, we studied the effect of H2O on the structural stability and catalytic performance of Mn-MOF-74. It was found that the interaction of Mn-O bonds was weakened by H2O. Therefore, the influence of H2O should be considered for the future design of MOF-based catalysts for the SCR process.

This paper reports on dihydroxycoumarins as fluorescent probes suitable for the detection and determination of the nitroxide radical, namely 4-amino-TEMPO. Since 4-amino-TEMPO is used as a spin label for the detection of various radicals and damage caused by these species, its determination under physiological conditions might help us to understand the mechanism of the oxidative stress. Among different coumarins studied, only dihydroxy-substituted derivatives show high sensitivity, specificity, and selectivity for the nitroxide radical. In this assay, dihydroxy-substituted coumarins under the action of 4-amino-TEMPO show a very fast and significant increase in fluorescence intensity and lifetime. Among them 6,7-dihydroxycoumarin (esculetin) exhibits the strongest fluorescence enhancement (up to 40 times), with an estimated limit of detection equal to 16.7 nM-a significantly lower value when compared with UV-Vis or electron paramagnetic resonance (EPR) spectroscopy. The method is characterized by an easy procedure of sample preparation and very short time of analysis. The mechanism of the interaction between 6,7-dihydroxycoumarin and 4-amino-TEMPO has been examined with the use of a series of complementary techniques, such as steady-state and time-resolved fluorescence spectroscopy, UV-Vis spectroscopy, electron paramagnetic resonance spectroscopy, potentiometric titration, and high-performance liquid chromatography. It has been proven that the only route of the reaction in the system studied is a proton transfer from the molecule of esculetin to the amino group of the nitroxide. Biological studies performed on prostate cancer cells, breast cancer cells, and normal skin fibroblasts revealed significant anticancer properties of 6,7-dihydroxycoumarin, which caused a considerable decrease in the viability and number of cancer cells, and affected their morphology, contrary to normal fibroblasts. Furthermore, the experiment performed on prostate cancer cells showed that fluorescence emission of esculetin is closely related to intracellular pH-the higher pH, the higher observed fluorescence intensity (in accordance with a chemical experiment). On the other hand, the studies performed in different pH levels revealed that when pH of the solution increases, the observed fluorescence intensity enhancement under the action of 4-amino-TEMPO decreases (better sensing properties of esculetin towards the nitroxide in lower pH).

The emission of nitrogen oxides has caused severe harm to the ecosystem; thus, the development of low-cost and high-efficiency denitrification catalysts and new methods are of great significance. In this work, a co-precipitation method was employed to prepare Pr-doped CeO 2 /attapulgite (CeO 2 /Pr 3+ /ATP) nanocomposites. X-ray diffraction (XRD), photoluminance spectroscopy (PL), ultraviolet-visible diffuse reflectance (UV-Vis), Fourier transform infrared (FT-IR), and high-resolution transmission electron microscopy (HRTEM) were utilized to characterize the products. Results showed that the CeO 2 /Pr 3+ nanoparticles were uniformly coated on the surface of ATP and demonstrated outstanding upconversion effect which converted the visible light to ultraviolet light. The upconversion luminescence of CeO 2 /Pr 3+ /ATP was strongest when the molar doping amount of Pr was 1 mol%, and the photo-SCR denitrification achieved the highest of 90% conversion and 95% selectivity when the loading amount of CeO 2 /Pr 3+ was 40 wt%. The ATP and CeO 2 /Pr 3+ constructed an indirect Z-type heterojunction structure mediated by oxygen vacancy which benefited the separation of charge carriers and enhanced the reduction-oxidation potentials, both are responsible for the remarkable denitrification performance.

The efficacy of advanced treatment of swine wastewater using thermally polymerized, modified amorphous silica and hydrated lime (M-CSH-lime) for color and phosphorus removal and sulfur for nitrogen removal was examined with a demonstration-scale treatment plant. The color removal rate was approximately 78% at M-CSH-lime addition rates of > 0.055 wt/v%. The PO43--P removal rate exceeded 99.9% with > 0.023 wt/v%. pH of the effluent from the M-CSH-lime reactor increased with the addition rate till a maximum value of 12.7, which was effective in disinfection. The recovered M-CSH-lime would be suitable as a phosphorus fertilizer because the total P 2 O 5 content was approximately 10%. The nitrogen oxide (NOx-N) removal rate by sulfur denitrification increased to approximately 80% when the NOx-N loading rate was around 0.1 kg-N/ton-S/day. It was suggested that the combination of the two processes would be effective in the advanced treatment of swine wastewater., (© 2017 Japanese Society of Animal Science.)

Removal kinetics for NO and SO 2 by NaClO 2 solution mist were investigated in a wet electrostatic precipitator. By varying the molar concentrations of NO, SO 2 , and NaClO 2 , the removal rates of NO and SO 2 confirmed to range from 34.8 to 72.9 mmol/m 3  s and 36.6 to 84.7 mmol/m 3  s, respectively, at a fixed gas residence time of 0.25 s. The rate coefficients of NO and SO 2 were calculated to be 0.679 (mmol/m 3 ) -0.33  s -1 and 1.401 (mmol/m 3 ) -0.1  s -1 based on the rates of the individual removal of NO and SO 2 . Simultaneous removal of NO and SO 2 investigated after the evaluation of removal rates for their individual treatment was performed. At a short gas residence time, SO 2 gas removed more quickly by a mist of NaClO 2 solution than NO gas in simultaneous removal experiments. This is because SO 2 gas, which has a relatively high solubility in solution, was absorbed more rapidly at the gas-liquid interface than NO gas. NO and SO 2 gases were absorbed as nitrite [Formula: see text] and sulfite [Formula: see text] ions, respectively, by the NaClO 2 solution mist at the gas-liquid interface. Then, [Formula: see text] and [Formula: see text] were oxidized to nitrate [Formula: see text] and sulfate [Formula: see text], respectively, by reactions with [Formula: see text], ClO 2 , HClO, and ClO in the liquid phase.

Free radicals, particularly reactive oxygen species (ROS), are involved in various pathologies, injuries related to radiation, ischemia-reperfusion or ageing. Unfortunately, it is virtually impossible to directly detect free radicals in vivo, but the redox status of the whole organism or particular organ can be studied in vivo by using magnetic resonance techniques (EPR and MRI) and paramagnetic stable free radicals - nitroxides. Here we review results obtained in vivo following the pharmacokinetics of nitroxides on experimental animals (and a few in humans) under various conditions. The focus was on conditions where the redox status has been altered by induced diseases or harmful agents, clearly demonstrating that various EPR/MRI/nitroxide combinations can reliably detect metabolically induced changes in the redox status of organs. These findings can improve our understanding of oxidative stress and provide a basis for studying the effectiveness of interventions aimed to modulate oxidative stress. Also, we anticipate that the in vivo EPR/MRI approach in studying the redox status can play a vital role in the clinical management of various pathologies in the years to come providing the development of adequate equipment and probes., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)

A novel chemical absorption-biological reduction (CABR) integrated process, employing ferrous ethylenediaminetetraacetate (Fe(II)EDTA) as a solvent, is deemed as a potential option for NOx removal from the flue gas. Previous work showed that the Fe(II)EDTA concentration was critical for the NOx removal in the CABR process. In this work, the pathway of FeEDTA (Fe(III)/Fe(II)-EDTA) transformation was investigated to assess its impact on the NOx removal in a biofilter. Experimental results revealed that the FeEDTA transformation involved iron precipitation and EDTA degradation. X-ray photoelectron spectroscopy analysis confirmed the iron was precipitated in the form of Fe(OH)3. The iron mass balance analysis showed 44.2% of the added iron was precipitated. The EDTA degradation facilitated the iron precipitation. Besides chemical oxidation, EDTA biodegradation occurred in the biofilter. The addition of extra EDTA helped recover the iron from the precipitation. The transformation of FeEDTA did not retard the NO removal. In addition, EDTA rather than the iron concentration determined the NO removal efficiency.

Non-thermal plasma (NTP) has been introduced over the last few years as a promising after- treatment system for nitrogen oxides and particulate matter removal from diesel exhaust. NTP technology has not been commercialised as yet, due to its high rate of energy consumption. Therefore, it is important to seek out new methods to improve NTP performance. Residence time is a crucial parameter in engine exhaust emissions treatment. In this paper, different electrode shapes are analysed and the corresponding residence time and NOx removal efficiency are studied. An axisymmetric laminar model is used for obtaining residence time distribution numerically using FLUENT software. If the mean residence time in a NTP plasma reactor increases, there will be a corresponding increase in the reaction time and consequently the pollutant removal efficiency increases. Three different screw thread electrodes and a rod electrode are examined. The results show the advantage of screw thread electrodes in comparison with the rod electrode. Furthermore, between the screw thread electrodes, the electrode with the thread width of 1 mm has the highest NOx removal due to higher residence time and a greater number of micro-discharges. The results show that the residence time of the screw thread electrode with a thread width of 1 mm is 21% more than for the rod electrode.

The presence of NO9x) gases (NO+NO2) in the atmosphere is a major concern of society because of their associated adverse and harmful effects. In order to remove the NO(x) gases from the air, photocatalysis arises as an innovative and promising technique. Through the use of photochemical oxidation processes the NO and NO2 gases are oxidised to NO3- form and thus removed from the air. In recent years new nanomaterials are being developed by researchers with the aim to enhance their photocatalytic activity to combat the NO(x) pollution. The main focus is devoted to preparing new TiO2 based compounds with the highest specific surface area (SSA), different morphology and chemical modifications. In order to increase the SSA, different substrates were used to disperse the TiO2 nanoparticles: organic and carbon fibres, mesoporous materials, clays composites and nanoporous microparticles. In the other hand, high photocatalytic performances were obtained with nanotubes, self-orderer nano-tubular films and nanoparticles with the lowest size. Conversely, when TiO2 is doped with ions the oxide exhibited a better photocatalytic performance under visible light, which is related to the creation of intermediate energy states between the conduction band and the valence band. Alternatively, visible light photocatalysts different from titanium oxide have been studied, which exhibit a good De-NO(x) efficiency working under λ > 400 nm visible light irradiation.

The pilot-scale plant on the simultaneous removal of PCDD/Fs and NOx from the flue gas of a municipal solid waste incinerator is presented. In order to research the influence of temperature on the catalytic decomposition of PCDD/Fs and the selective catalytic reduction of NOx, the experiments were performed at 220 °C, 260 °C, and 300 °C, and the congener profiles of PCDD/Fs for the samples collected at the inlet and outlet were illustrated. Noteworthy, the detailed congener distributions of PCDD/Fs in the gas-phase and particle-phase of the inlet and 300-outlet (decomposition temperature = 300 °C) samples are presented, and the removal efficiencies η(g-I-TEQ) and η(p-I-TEQ) reached to 94.94% and 99.67%, respectively. The effect of the SCR process on the removal of PCDD/Fs was also studied at a relatively low temperature of 220 °C. Additionally, the NOx emissions and the SCR efficiencies were investigated., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

SOx and NOx are emissions resulting from combustion processes and are the main agents that contribute to the formation of acid rain, which causes harm to humans and the environment. Several techniques for removing these pollutants are applied in i.e. oil refineries, thermoelectric that use petroleum oils and vehicular pollution. Among these, highlight the adsorption of contaminants by the usage of activated carbon fibers and activated carbon, which are characterized by high surface area and uniform distribution of pores, providing appropriate conditions for application in processes of removing environmental contaminants. In the present work, activated viscose fibers (AVF) were prepared and applied in adsorption experiments of NO and SO2. The materials produced showed high values of surface area, with a predominance of micro pores with diameters in the range of 1.0 nm. The AVF had satisfactory performance in the removal of contaminants and are compatible with other synthetic fibers. Thus, the formation of active sites of carbon provides contaminants adsorption, demonstrating that carbon fibers cloth can be applied for the removal of pollutants.

NOx, a significant portion of fossil fuel flue gases, are among the most serious environmental issues in the world and must be removed in an additional costly gas treatment step. This study evaluated the growth of the green alga Chlorella sp. C2 under a nitrite-simulated NOx environment and the removal rates of actual flue gas fixed salts (FGFSs) from Sinopec's Shijiazhuang refinery along with lipid production. The results showed that nitrite levels lower than 176.5 mM had no significant adverse effects on the cell growth and photosynthesis of Chlorella sp. C2, demonstrating that this green alga could utilize nitrite and NOx as a nitrogen source. High concentrations of nitrite (88.25-176.5 mM) also resulted in the accumulation of neutral lipids. A 60% nitrite removal efficiency was obtained together with the production of 33% algae lipids when cultured with FGFS. Notably, the presence of nitrate in the FGFS medium significantly enhanced the nitrite removal capability, biomass and lipid production. Thus, this study may provide a new insight into the economically viable application of microalgae in the synergistic combination of biological DeNOx of industrial flue gases and biodiesel production.

Nitrogen monoxide (NO) and nitrogen dioxide referred as NOx are one of the most important air pollutants in the atmosphere. Biological NOx removal technologies have been developing to reach a cost-effective control method for upcoming stringent NOx emission standards. The BioDeNOx system was seen as a promising biological NOx control technology which is composed of two reactors, one for absorbing of NO in an aqueous Fe(II)EDTA2- solution and the other for subsequent reduction to N2 gas in a biological reactor by the denitrification process. In this study, instead of two discrete reactors, only one jet-loop bioreactor (JLBR) was utilized as both absorption and denitrification unit and no chelate-forming chemicals were added. In other words, the advantage of better mass transfer conditions of jet bioreactor was used instead of Fe(II)EDTA2-. The process was named as Jet-BioDeNOx. The JLBR was operated for the removal of NOx from air streams containing 500-3000 ppm NOx and the results showed that the removal efficiency was between 81% and 94%. The air to liquid flow ratio (Q(G)/Q(RAS)) varied in the range of 0.07-0.12. Mathematical modelling of the system demonstrated that the removal efficiency strongly depends on this ratio. The high mass transfer conditions prevailed in the reactor provided a competitive advantage on removing NO gas without any requirement of chelating chemicals.

Mn-based catalysts enable high NO x conversion in the selective catalytic reduction of NO x with NH3. Three catalyst-production methods, namely, co-precipitation, impregnation, and sol-gel, were used in this study to determine the optimum method and parameters. The maximum catalytic activity was found for the catalyst prepared by sol-gel with a 0.5 Mn/Ti ratio. The denitrification efficiency using this catalyst was >90%, which was higher than those of catalysts prepared by the two other methods. The critical temperature of catalytic activity was 353 K. The optimum manganese acetate concentration and weathering time were 0.10 mol and 24 h, respectively. The gas hourly space velocity and O2 concentration were determined to be 12000 h(-1) and 3%, respectively.

This work developed an electrochemical reduction system which can effectively scrub NO× from flue gas by using aqueous solution of Fe(II)(EDTA) (ethylenediaminetetraacetate) as absorbent and electrolyte. This new system features (a) complete decomposition of NOX to harmless N2; and (b) fast regeneration of Fe(II)(EDTA) through electrochemical reaction. The Fe(II)(EDTA) solution was recycled and reused continuously during entire process, and no harmful waste was generated. The reaction mechanism was thoroughly investigated by using voltammetric, chromatographic and spectroscopic approaches. The operating conditions of the system were optimized based on NOX removal efficiency. Approximately 98% NO removal was obtained at the optimal condition. The interference of SO2 in flue gas and the system operating stability was also evaluated.

A photocatalytic HC/SCR system has been developed and its high deNOx performance (54.0-98.6% NOx conversion) at low temperatures (150-250 °C) demonstrated by using a representative diesel fuel hydrocarbon (dodecane) as the reductant over a hybrid SCR system of a photocatalytic reactor (PCR) and a dual-bed HC/SCR reactor. The PCR generates highly active oxidants such as O3 and NO2 from O2 and NO in the feed stream, followed by the subsequent formation of highly efficient reductants such as oxygenated hydrocarbon (OHC), NH3, and organo-nitrogen compounds. These reductants are the key components for enhancing the low temperature deNOx performance of the dual-bed HC/SCR system containing Ag/Al2O3 and CuCoY in the front and rear bed of the reactor, respectively. The OHCs are particularly effective for both NOx reduction and NH3 formation over the Ag/Al2O3 catalyst, while NH3 and organo-nitrogen compounds are effective for NOx reduction over the CuCoY catalyst. The hybrid HC/SCR system assisted by photocatalysis has shown an overall deNOx performance comparable to that of the NH3/SCR, demonstrating its potential as a promising alternative to the current urea/SCR and LNT technologies. Superior durability of HC/SCR catalysts against coking by HCs has also been demonstrated by a PCR-assisted regeneration scheme for deactivating catalysts.

Biological reduction of Fe(III) to Fe(II) is a key step in nitrogen oxides (NOx) removal by the integrated chemical absorption-biological reduction method, which determines the concentration of Fe(II) in the scrubbing liquid. A new Fe(III)EDTA reduction strain, named as FD-3, was isolated from mixed cultures used in the integrated NOx removal process and identified as Klebsiella sp. by 16S rDNA sequence analysis. The reduction abilities of FD-3 and the influence of nitrogen-containing compounds (Fe(II)EDTA-NO, NO3(-) and NO2(-)) and sulfur-containing compounds (SO4(2-), SO3(2-)) on the Fe(III)EDTA reduction were investigated. The results indicated that strain FD-3 could reduce Fe(III)EDTA efficiently. NO3(-), NO2(-) and Fe(II)EDTA-NO inhibit the reduction of Fe(III)EDTA and could also serve as electron acceptor for strain FD-3. SO3(2-) inhibited Fe(III)EDTA reduction while SO4(2-) had no obviously effect on Fe(III)EDTA reduction. The relationship between cell growth and Fe(III)EDTA reduction could be described by the models based on Logistic equation., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The effects of NO(x) oxidation ratio, O2 and SO2 concentrations in simulated flue gas as well as addition of S(IV) oxidation inhibitor NaS2O3 on the simultaneous removal of SO2 and NO(x) by ammonia absorption were investigated under the conditions of pH 5.9-6.1 and aqueous S(IV) concentration > or = 1.0 mol x L(-1). The research results showed that NO2 could be effectively absorbed by ammonium sulfite, but the NO absorption was negligible. Therefore, NO oxidation is the premise of NO(x) removal. Aqueous S(IV) concentration is a key factor affecting NO2 absorption removal, the higher the O2 concentration or the lower the SO2 concentration, the faster the aaqueous S(IV) concentration decreased, which resulted in a faster decrease of NO2 removal efficiency. S(IV) oxidation was inhibited to some extent by the addition of oxidation inhibitor S2O3(2-) into the absorption solution. As a result, the decrease of NO2 removal efficiency became slower.

Unlabelled: Experimental studies on desulfurization and denitrification were carried out using activated carbon irradiated by microwave. The influences of the concentrations of nitric oxide (NO) and sulfur dioxide (SO2), the flue gas coexisting compositions, on adsorption properties of activated carbon and efficiencies of desulfurization and denitrification were investigated. The results show that adsorption capacity and removal efficiency of NO decrease with the increasing of SO2 concentrations in flue gas; adsorption capacity of NO increases slightly first and drops to 12.79 mg/g, and desulfurization efficiency descends with the increasing SO2 concentrations. Adsorption capacity of SO2 declines with the increasing of O2 content in flue gas, but adsorption capacity of NO increases, and removal efficiencies of NO and SO2 could be larger than 99%. Adsorption capacity of NO declines with the increase of moisture in the flue gas, but adsorption capacity of SO2 increases and removal efficiencies of NO and SO2 would be relatively stable. Adsorption capacities of both NO and SO2 decrease with the increasing of CO2 content; efficiencies of desulfurization and denitrification augment at the beginning stage, then start to fall when CO2 content exceeds 12.4%. The mechanisms of this process are also discussed., Implications: The prominent SO2 and NOx treatment techniques in power plants are wet flue gas desulfurization (FGD) and the catalytic decomposition method like selective catalytic reduction (SCR) or nonselective catalytic reduction (NSCR). However, these processes would have some difficulties in commercial application due to their high investment, requirement of expensive catalysts and large-scale equipment, and so on. A simple SO2 and NOx reduction utilizing decomposition by microwave energy method can be used. The pollutants control of flue gas in the power plants by the method of microwave-induced decomposition using adsorption of activated carbon/microwave desorption can meet the requirements of environmental protection, which will be stricter in the future.

The kinetic mechanism of NOx reduction with hydrazine hydrate in selective non-catalytic reduction (SNCR) process was studied and verified by the experimental results, the dominant radicals and reactions were confirmed through sensitivity analysis and key parameters in SNCR process have been obtained. The results of numerical simulation based on the proposed mechanism showed that the effective temperatures for SNCR de-NOx process were bimodal distribution with the optimum temperatures being 650 degrees C and 975 degrees C respectively and the lower temperature window fell in the range of 597-747 degrees C; while the experimental results proved the bimodal distribution of effective temperature with peak values being 653 degrees C and 968 degrees C respectively and the lower temperature window was within the range of 587-707 degrees C for hydrazine-based SNCR process, Simulation results and experimental results matched well with respect to reaction behaviors versus temperature. Through sensitivity analysis it had been found that the most effective reaction to reduce NO was the decomposition reaction of N2H4 to NH2 and the most helpful radical was NH2. Compared to ammonia the temperature window of hydrazine-based SNCR process on the lower temperature side is more flexible for application. Decreased O2 concentration would move the temperature window to the right side, which was contrary to that of ammonia; while increased n(N2H4)/n(NO) moved the temperature window to the left side and NO, reduction efficiency was also improved. All of these results showed that hydrazine has lower temperature window than those traditional de-NOx reagents and it will be widely used in application of SNCR as a potential reductant for NOx reduction.

TiO(2) hybridized with HZSM-5 zeolites photocatalysts were prepared by a simple solid state dispersion method. The physicochemical properties of the catalysts were characterized by X-ray diffraction, UV-vis diffuse reflectance and FT-IR spectroscopy. The photocatalytic oxidation of NO(x) over TiO(2)/HZSM-5 having different Si/Al ratios was carried out under various levels of humidity and different pre-adsorption times in dark. The TiO(2)/HZSM-5 composite catalysts exhibited higher NO conversion and lower NO(2) formation than pure TiO(2). Pre-adsorption with water vapor and the high humidity during the photoreaction were harmful to the reactivity of TiO(2) hybridized with hydrophilic HZSM-5 zeolite. However, the photocatalytic reactivity of TiO(2) hybridized with hydrophobic zeolite varied little with increase in humidity. The results indicated that the high photocatalytic reactivity of TiO(2)/HZSM-5 catalysts is largely depended on the hydrophobicity of the zeolites., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Experimental studies were carried out on flue gas denitrification using activated carbon irradiated by microwave. The effects of microwave irradiation power (reaction temperature), the flow rate of flue gas, the concentration of NO and the flue gas coexisting compositions on the adsorption property of activated carbon and denitrification efficiency were investigated. The results show that: the higher of microwave power, the higher of denitrification efficiency; denitrification efficiency would be greater than 99% and adsorption capacity of NO is relatively stable after seven times regeneration if the microwave power is more than 420 W; adsorption capacity of NO in activated carbon bed is 33.24 mg/g when the space velocity reaches 980 per hour; adsorption capacity declines with increasing of the flow rate of flue gas; the change in denitrification efficiency is not obvious with increasing oxygen content in the flue gas; and the maximum adsorption capacity of NO was observed when moisture in flue gas was about 5.88%. However, the removal efficiency of NO reduces with increasing moisture, and adsorption capacity and removal efficiency of NO reduce with increasing of SO2 concentration in the flue gas.

Fe-MnOx-CeO2/ZrO2 catalysts were prepared through impregnation method with nanometer ZrO2 as a carrier and used in selective catalytic reduction of NO with NH3 at low temperature. Effects of active component ratio and loading of promoter on the catalyst activity were investigated. The catalysts were characterized by means of XRD, SEM, EDS and BET. The effects of temperature, SO2 and H2O on NO conversion were studied and the results showed that in the absence of SO2 and H2O, the catalyst of 8% Fe-10% MnOx-CeO2/ZrO2 had good activity and stability as well as the NOx removal efficiency reached 85.23% at 120 degrees C and 92.0% at 180 degrees C. The presence of SO2 and H2O results in the catalyst deactivated. Properties of the catalyst on different reaction stages were characterized by FT-IR to study the inactivation mechanism of the catalyst. The results showed that the catalyst deactivation was due to the deposition of ammonium sulfate on the catalyst and the sulphation of the catalyst.

The removal of NO(X) at high temperature by Chelatococcus daeguensis TAD1 in a biotrickling filter was studied. Media components of the recycling liquid were screened using Plackett-Burman design and then were optimized using response surface methodology, which enhanced the efficiency of nitrate removal by TAD1. The optimal medium was used to perform long-term experiments of NO(X) removal in a biotrickling filter under high concentrations of O(2) and NO in simulated flue gas. Results showed that the biotrickling filter was able to consistently remove 80.2-92.3% NO(X) when the inlet NO concentration was 600ppm under the conditions of oxygen concentration ranging between 2% and 20% and empty bed residence time (EBRT) being 112.5s. Analyses by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) indicated that TAD1 was always predominant in the biofilm under a flue gas environment. Overall, the present study demonstrated that utilizing a biotrickling filter inoculated with the aerobic denitrifier TAD1 to remove NO(X) at high temperature was practically feasible., (Copyright © 2011 Elsevier B.V. All rights reserved.)

This paper presents a study on the simultaneous removal of SO2, NO(x) and Hg (both Hg0 and Hg2+) from a simulated flue gas by oxidant injection in a bench-simulated wet limestone scrubber for a wide range of slurry pH. The slurry pH strongly influenced the chemical mechanism in the scrubber and, therefore, affected pollutant removal. This paper also examines the potential ClO2(gas) reemission from a developed multipollutant scrubber at different slurry pHs. To better understand the chemical mechanisms at each slurry pH and to apply a mass balance to the process, detailed product ion analyses were performed for all experiments. Ion analysis covered three different chlorine species (chlorite, chloride, chlorate), sulfate, nitrite and nitrate. Different NO(x) removal efficiencies and mechanisms were found in acidic and alkaline pHs in the multipollutant scrubber. The acidic solution was favorable for NO and Hg0 oxidation, but increasing the slurry pH above 7.0 was disadvantageous for NO and Hg oxidation/removal. However the rate of NO(x) absorption (by percentage) was higher for the alkaline solution.

A mixed absorbent had been proposed to enhance the chemical absorption-biological reduction process for NO(x) removal from flue gas. The mole ratio of the absorbent of Fe(II)Cit to Fe(II)EDTA was selected to be 3. After the biofilm was formed adequately, some influential factors, such as the concentration of NO, O(2), SO(2) and EBRT were investigated. During the long-term running, the system could keep on a steady NO removal efficiency (up to 90%) and had a flexibility in the sudden changes of operating conditions when the simulated flue gas contained 100-500 ppm NO, 100-800 ppm SO(2), 1-5% (v/v) O(2), and 15% (v/v) CO(2). However, high NO concentration (>800 ppm) and relative short EBRT (<100s) had significant negative effect on NO removal. The results indicate that the new system by using mixed-absorbent can reduce operating costs in comparison with the single Fe(II)EDTA system and possesses great potential for scale-up to industrial applications., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Experimental researches were carried out on the inhibition effects of carbohydrazide (CHZ) on NO(x) and dioxin emissions under moderate to high temperatures, namely De-NO(x) effect of CHZ was investigated in the temperature range of 450-1 050 degrees C with the O2 concentration between 10.1% and 16.7%; and its suppression effect on dioxin emissions was studied both by spraying CHZ solution into incineration flue gases and by mixing CHZ in iron ore in the sintering pot. It was proved that CHZ could reduce NO(x) with dual temperature-linked peaks, i. e. the De-NO(x) efficiency peaks appeared both around 600 degrees C and 967 degrees C, with a vale around 850 degrees C. The results also indicated that CHZ had good suppression effect on dioxin synthesis in the fly ash precipitated in the temperature range of 250-450 degrees C when CHZ solution was sprayed into flue gases at proper temperatures; comparably, for dioxin emissions from the iron ore sintering pot, the more CHZ mixed into iron ore, the less dioxin emissions took place; when the mixture proportion of CHZ (mass fraction) was up to 0.1%, the concentration of PCDD/Fs in TEQ in sintering flue gases was decreased by 78.8% compared to the scenario without CHZ mixing, showing that CHZ is an effective inhibitors for reducing dioxin emissions in the iron ore sintering furnace. All of these results showed that CHZ is a potential inhibitor for dioxin emissions from incinerators and iron ore sintering furnaces as well as a reduction agent for NO(x).

A series of V(2)O(5)/TiO(2)-carbon nanotube (CNT) catalysts were synthesized by sol-gel method, and their activities for NO(X) removal were compared. A catalytic promotional effect was observed by adding CNTs to V(2)O(5)/TiO(2). The catalyst V(2)O(5)/TiO(2)-CNTs (10wt.%) showed an NO(X) removal efficiency of 89% at 300°C under a GHSV of 22,500h(-1). Based on X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, NH(3)-temperature-programmed desorption, temperature-programmed reduction, Brunauer-Emmett-Teller surface area measurements, differential scanning calorimetry, and thermogravimetric analysis, the increased acidity and reducibility, which could promote NH(3) adsorption and oxidation of NO to NO(2), respectively, contributed to this promotion., (Copyright © 2011 Elsevier B.V. All rights reserved.)

An optimized aerobic denitrifying bacteria was applied to a biofilter for the removal of NO(x). The removal process of NO(x) was investigated, and the relationship between environmental factors and NO(x) removal efficiency as well as the NO(x) transfermechanism under aerobic conditions are discussed. The results show that the biofilter finished start-up after 26 days and the presence of oxygen has no evident negative effect on the efficiency of NO(x) removal. Mainly happening at the middle and under part of the biofiltration system, the removal of NO(x) get a high efficiency of 93.6% at the EBRT of 59s and the inlet NO(x) concentration of 286.4 mg/m3 with 10% O2. A special biomembrane system was formulated by nitrobacteria, facultative denitrifying bacteria and aerobic denitrifying bacteria in the biofiltration system.

An innovative semidry process has been developed to simultaneously remove NO and SO₂ from flue gas. According to the conditions of the flue gas circulating fluidized bed (CFB) system, ferrate(VI) absorbent was prepared and added to humidified water, and the effects of the various influencing factors, such as ferrate(VI) concentration, humidified water pH, inlet flue gas temperature, residence time, molar ratio of Ca/(S+N), and concentrations of SO₂ and NO on removal efficiencies of SO₂ and NO were studied experimentally. Removal efficiencies of 96.1% for SO₂ and 67.2% for NO were obtained, respectively, under the optimal experimental conditions, in which the concentration of ferrate(VI) was 0.03 M, the humidified water pH was 9.32, the inlet flue gas temperature was 130 °C, the residence time was 2.2 s, and the molar ratio of Ca/(S+N) was 1.2. In addition, the reaction mechanism of simultaneous desulfurization and denitrification using ferrate(VI) was proposed.

An updated version of the Statewide Air Pollution Research Center (SAPRC) chemical mechanism (SAPRC07C) was implemented into the Community Multiscale Air Quality (CMAQ) version 4.6. CMAQ simulations using SAPRC07C and the previously released version, SAPRC99, were performed and compared for an episode during July-August, 2000. Ozone (O3) predictions of the SAPRC07C simulation are generally lower than those of the SAPRC99 simulation in the key areas of central and southern California, especially in areas where modeled concentrations are greater than the federal 8-hr O3 standard of 75 parts per billion (ppb) and/or when the volatile organic compound (VOC)/nitrogen oxides (NOx) ratio is less than 13. The relative changes of ozone production efficiency (OPE) against the VOC/NOx ratio at 46 sites indicate that the OPE is reduced in SAPRC07C compared with SAPRC99 at most sites by as much as approximately 22%. The SAPRC99 and SAPRC07C mechanisms respond similarly to 20% reductions in anthropogenic VOC emissions. The response of the mechanisms to 20% NOx emissions reductions can be grouped into three cases. In case 1, in which both mechanisms show a decrease in daily maximum 8-hr O3 concentration with decreasing NOx emissions, the O3 decrease in SAPRC07C is smaller. In case 2, in which both mechanisms show an increase in O3 with decreasing NOx emissions, the O3 increase is larger in SAPRC07C. In case 3, SAPRC07C simulates an increase in O3 in response to reduced NOx emissions whereas SAPRC99 simulates a decrease in O3 for the same region. As a result, the areas where NOx controls would be disbeneficial are spatially expanded in SAPRC07C. Although the results presented here are valuable for understanding differences in predictions and model response for SAPRC99 and SAPRC07C, the study did not evaluate the impact of mechanism differences in the context of the U.S. Environmental Protection Agency's guidance for using numerical models in demonstrating air quality attainment. Therefore, additional study is required to evaluate the full regulatory implications of upgrading air quality models to SAPRC07.

To conduct low oxides of nitrogen (NOx) chamber experiments with modern diesel emissions (DE), a high-capacity NO, denuder was developed and used at the European Photoreactor (EUPHORE) outdoor simulation chamber. The denuder displayed a sufficient NOx storage capacity for use with DE, and efficient removal of NO, during injections of DE was achieved (>98%). Degradation of the denuder performance after repeated regeneration by heating (400 degrees C) and flushing with an air/oxygen ratio of 2:1 was not observed for a total of nine experiments. Evaluation of dark (with chamber cover closed) experiments (four in total) with and without the denuder in-line revealed some reduction (22%) of diesel particulate matter (DPM) with use of the denuder, most likely a result of impaction or settling of DPM during DE transit. However, DPM reduction may have also been a result of reductions in effective load of the engine-dyno system during the DE injections. Extensive chemical characterization of DPM revealed no significant perturbation of major compound groups associated with denuder use, except for nitrated polyaromatic hydrocarbon (NPAH) concentrations. The implications of high-NOx experiments without the use of a NOx denuder are discussed.

Simultaneous removal of NO(x) and SO2 from exhausted gas were investigated by studying co-culture of sulfate reducing bacteria and anaerobic denitrifying bacteria, separated from landfill leachate. When H2S, generated by sulfate reducing bacteria was chosen as the sole electron donor for anaerobic denitrifying bacteria, the co-culture system demonstrated a faster NO removal rate, higher stability and better permanence. When the feed gas flow rates of N2 and SO2 were maintained constant at 0.1 m3/h and 16 ml/min respectively, the maximum NO-removal rate could be achieved at over 92% with NO feed gas kept between 2-6 ml/min, while the SO2 removal rate was always above 95%. Long-term continuous removal of NO exhibited an evident periodicity of five days, however, the fluctuation range of NO-removal was decreasing. Moreover, the decrease of the gas flow rate and the increase in NO inlet concentration could contribute to a higher NO- removal rate.

Nitric oxide, NO, the diatomic hybrid of dinitrogen and dioxygen, has extensive biochemical, industrial and atmospheric chemistry. The unpaired electron on NO makes it highly reactive and its facile oxidation and reduction to make (NO)(1+) and (NO)(1-), respectively, have been heavily studied. Now the (NO)(2-) dianion has been isolated for the first time from the two-electron reduction of NO by the recently discovered (N(2))(3-) yttrium complex {[(Me(3)Si)(2)N](2)(THF)Y}(2)(micro(3)-eta(2):eta(2):eta(2)-N(2))K. NO reacts with this complex to form {[(Me(3)Si)(2)N](2)(THF)Y}(2)(micro-eta(2):eta(2)-NO), a paramagnetic complex that has an electron paramagnetic resonance spectrum definitive for the (NO)(2-) radical. Density functional theory reveals that a metal d(pi) to ligand pi* interaction is crucial for the stability of this complex, which reacts with additional NO to generate the diamagnetic (ON=NO)(2-) product, {[(Me(3)Si)(2)N](2)Y}(4)(micro(3)-ON=NO)(2)(THF)(2).

A multi-level assessment index system was established to quantitatively and comprehensively evaluate the performance of typical nitrogen oxide control technologies for coal-fired power plants. Comprehensive fuzzy evaluation was conducted to assess six NO, control technologies, including low NO, burner (LNB), over the fire (OFA), flue gas reburning (Reburning), selective catalyst reduction (SCR), selective non-catalyst reduction (SNCR) and hybrid SCR/SNCR. Case studies indicated that combination of SCR and LNB are the optimal choice for wall-fired boilers combusting anthracite coal which requires NO, removal efficiency to be over 70%, however, for W-flame or tangential boilers combusting bituminous and sub-bituminous coal which requires 30% NO, removal, LNB and reburning are better choices. Therefore, we recommend that in the developed and ecological frangible regions, large units burning anthracite or meager coal should install LNB and SCR and other units should install LNB and SNCR. In the regions with environmental capacity, units burning anthracite or meager coal shall install LNB and SNCR, and other units shall apply LNB to reduce NO, emissions.

A small-scale field trial in Umeå, Sweden with Ogawa samplers and a chemiluminescence instrument indicated that the NO(2) concentration was underestimated with respect to the reference monitor, if calculated according to the manufacturer's Ogawa sampling protocol. By co-locating Ogawa samplers and reference monitors at six sites in two Swedish cities, uptake rates were determined for NO(2) and NO(x) better applicable to the Swedish conditions and climate. The concentrations of NO(2) and NO(x) calculated according to the instruction manual of the sampler and using the field-determined uptake rates were compared with values derived from chemiluminescence monitors for each week over which samples were taken. When calculated according to the manufacturer's suggested protocol, the Ogawa sampler underestimated the NO(2) concentrations by 9.1% on average for all samples (N = 53), with respect to the reference monitor. In contrast, NO(x) concentrations were overestimated by a mean value of 15% for all samples (N = 45). By using the field determined uptake rates for the calculation of NO(2) and NO(x) a better estimation of the concentrations was obtained. The ratio between concentrations determined with the Ogawa samplers and chemiluminescence monitors was then 1.02 for all measurements of NO(2) and 1.00 for NO(x). Precision, expressed as the mean coefficient of variation, was 6.4% for six, 6-replicate measurements of NO(2) and 3.7% for five, 6-replicate measurements of NO(x).

The successful in situ synthesis of platinum nanoparticles (PtNPs) on a microstructured paperlike matrix, comprising ceramic fibers as main framework and zinc oxide whiskers as selective support for the PtNPs, is reported. The as-prepared hybrid material (PtNPs@ZnO "paper") resembles ordinary paper products because it is flexible, lightweight, and easy to handle. In the catalytic reduction of nitrogen oxide (NO(x)) with propene for exhaust gas purification, the PtNPs@ZnO paper demonstrates a high catalytic performance at a low reaction temperature, with one-third the dosage of precious platinum compared to conventional platinum-loaded honeycomb catalysts. These results imply that the combination of easily synthesized PtNPs and a unique fiber-network microstructure can provide excellent performances, promoting the effective transport of heat and reactants to the active sites of the platinum nanocatalysts. Thus, PtNPs@ZnO materials with paperlike practical aspects are promising catalytic materials for efficient NO(x) gas purification.

This paper reported the potential of heterogeneous photocatalysis as an advanced oxidation technology for NO(x) removal from vehicle emissions by using TiO(2) as a photocatalyst immobilized on the surface of asphalt road. Based on asphalt road material porous characteristic, we utilized permeability technology to make asphalt nano-TiO(2) to be environmental protection materials. And then using scanning electron microscope, we observed the penetrating effect of TiO(2). The effect of surface friction, humidity and light intensity on NO(x) removal had been systematically investigated by the use of TiO(2) immobilized on the surface of asphalt road as photocatalytic environmental protection materials. In addition, the decontaminating effect was tested by contrast test in TiO(2) spraying section with non-spraying section, while the productions were used in road environment. Results of experiment revealed that decontaminating rate of the productions ranged from 6% to 12% this kind of photochemical catalysis environmental protection material has good environment purification function.

The main target of this work is to characterize the abatements of particulate matter (PM), hydrocarbons (HC) and nitrogen oxides (NO(x)) from an actual diesel exhaust using dielectric barrier discharge technology (DBD). The effects of several parameters, such as peak voltage, frequency and engine load, on the contaminant removals have been investigated intensively. The present study shows that for a given frequency, the removals of PM and HC are enhanced with the increase of peak voltage and level off at higher voltage, while in the range of higher voltages a decline of NO(x) removal efficiency is observed. For a given voltage, the maximums of specific energy density (SED) and removal efficiency are attained at resonance point. The increase of peak voltage will result in a significant decrease of energy utilization efficiency of DBD at most engine loads. Alkanes in soluble organic fraction (SOF) are more readily subjected to removals than polycyclic aromatic hydrocarbons (PAHs).

The objective of this work was to study the effect of some operating conditions on the simultaneous removal of NO(x) and SO2 from simulated NO-SO2-air flue-gas mixtures in a scrubber column. The gaseous components were absorbed into 6M HNO3 electrolyte in the scrubber in a counter-current mode, and were oxidatively removed by the Ag(II) mediator oxidant electrochemically generated in an electrochemical cell set-up. The integration of the electrochemical cell with the scrubber set-up ensured continuous regeneration of the Ag(II) mediator and its repeated reuse for NO(x) and SO2 removal purpose, thereby avoiding: (1) the usage of chemicals continuously for oxidation and (2) the production of secondary waste. The influences of packing material (raschig glass rings, raschig poly(vinylidene) fluoride rings, Jaeger tri-pack perfluoroalkoxy spheres), feed concentrations of NO and SO2 (100-400 ppm NO and 100-400 ppm SO2), superficial gas velocity (0.061-0.61ms(-1)) and liquid velocity (0.012-0.048 ms(-1)) were investigated. The raschig glass rings with high surface area provided highest NO removal efficiency. NO and NO(x) showed decreasing abatement at higher feed concentrations. The removal of nitrogen components was faster and also greater, when SO2 co-existed in the feed. Whereas the gas flow rate decreased the removal efficiency, the liquid flow rate increased it for NO and NOx. The flow rate effects were analyzed in terms of gas/liquid residence time and superficial liquid velocity/superficial gas velocity ratio. SO2 removal was total under all conditions.

Domestic wastewater is a significant source of nitrogen and phosphorus, which cause lake eutrophication. Among the wastewater treatment technologies, constructed wetlands are a promising low-cost means of treating point and diffuse sources of domestic wastewater in rural areas. However, the sustainable operation of constructed wetland treatment systems depends upon a high rate conversion of organic and nitrogenous loading into their metabolic gaseous end products, such as N2O and CH4. In this study, we examined and compared the performance of three typical types of constructed wetlands: Free Water Surface (FWS), Subsurface Flow (SF) and Vertical Flow (VF) wetlands. Pollutant removal efficiency and N2O and CH4 emissions were assessed as measures of performance. We found that the pollutant removal rates and gas emissions measured in the wetlands exhibited clear seasonal changes, and these changes were closely associated with plant growth. VF wetlands exhibited stable removal of organic pollutants and NH3-N throughout the experiment regardless of season and showed great potential for CH4 adsorption. SF wetlands showed preferable T-N removal performance and a lower risk of greenhouse gas emissions than FWS wetlands. Soil oxidation reduction potential (ORP) analysis revealed that water flow structure and plant growth influenced constructed wetland oxygen transfer, and these variations resulted in seasonal changes of ORP distribution inside wetlands that were accompanied by fluctuations in pollutant removal and greenhouse gas emissions.

The removals of NO by a wire-in-tube nonthermal plasma reactor combined with catalysis or in situ chemical absorption were investigated. Experimental results show that the plasma reduction of NO was much enhanced by the CuO catalyst in the reactor. On the other hand, for the catalytic reduction of NO, the reaction temperature was effectively decreased by the pulsed corona discharge. A NO reduction of 100% by the plasma reactor combined with CuO catalyst was achieved under the operation condition of inlet NO concentration 719 mg/m3, 1% CO, pulse voltage 18 kV and reaction temperature 473 K. For plasma combined with in situ absorption, it was found that NO removal was much higher than by the reactor without Ca(OH)2 sorbent. It was demonstrated that in situ absorption of NO oxidation products of NO2 and/or NO3 by Ca(OH)2 was responsible for the promotion of NO removal. NO removal of 100% was achieved for 1050 mg/m3 NO in a gas mixture of 2% O2 and 98% N2 with a pulse voltage of 18 kV.

A novel and effective system was developed for the complete treatment of NOx from flue gases. The system consisted of photocatalytic or ozone oxidation of NOx, followed by scrubbing and biological denitrification. Maximum photocatalytic oxidation of NOx was achieved while using powdered TiO2 at a catalytic loading rate of 10 g/h, relative humidity of 50%, and a space time of 10 s. The used catalyst was regenerated and reused. A total of 72% of oxidized NO was recovered as HNO3/HNO2 in the regeneration process. Stoichiometrically, 10% excess ozone was able to affect 100% oxidation of NO to NO2. Presence of SO2 adversely influenced the oxidation of NO by ozone. The scrubbing of NO was effective with distilled water. Heterotrophic denitrifiers were able to denitrify the leachate with an efficiency of 90%, using sewage (COD 450 mg/L) as electron donor. The new integrated treatment system seems to be a promising alternative for complete treatment of NOx from flue gases.

The main aim of this study was to develop an appropriate system for the thermal treatment of landfill leachate. In the initial phase of this study, characterization studies were conducted both for the waste disposed and leachate generated. For the thermal treatment of the landfill leachate two different incineration systems, namely a double-phase liquid waste incineration system and a new pilot-scale incineration system, were tested. During the experimental study, the capability of the new pilot-scale incineration system was proven to treat the landfill leachate. However, high concentrations of NOx were recorded. On the other hand, the experimental data, obtained during the testing period of the double-phase liquid waste incineration system, indicated that the fluidized bed incinerator provided an extra unit sufficient to complete the oxidation of partial products of combustion and organics carried from the initial incinerator. Therefore, lower gaseous emissions were noted. However, an agglomeration problem has occurred, due to the high concentrations of Na, Ca and K. It was concluded that considering the flexibility of the thermal processes, thermal treatment of leachate could successfully be applied to Odayeri landfill, as well as to many landfills, if proper gas treatment systems are applied.

A plasma reactor with catalysts was used to treat exhaust gas from a gasoline engine in order to decrease particulate matter (PM) emissions. The effect of non-thermal plasma (NTP) of the dielectric discharges on the removal of PM from the exhaust gas was investigated experimentally. The removal efficiency of PM was based on the concentration difference in PM for particle diameters ranging from 0.3 to 5.0 microm as measured by a particle counter. Several factors affecting PM conversion, including the density of plasma energy, reaction temperature, flow rate of exhaust gas, were investigated in the experiment. The results indicate that PM removal efficiency ranged approximately from 25 to 57% and increased with increasing energy input in the reactor, reaction temperature and residence time of the exhaust gas in the reactor. Enhanced removal of the PM was achieved by filling the discharge gap of the reactor with Cu-ZSM-5 catalyst pellets. In addition, the removal of unburned hydrocarbons was studied. Finally, available approaches for PM conversion were analyzed involving the interactions between discharge and catalytic reactions.

Decomposition characteristics of two groups of representative mixed malodorants (1, ethanethiol + hydrogen sulfide; 2, ethanethiol + ammonia) in air were investigated employing a wire-plate pulse corona reactor. A new type of high-voltage pulse generator with a thyratron switch and a Blumlein pulse-forming network (BPFN) was used in our experiments. The experiments were conducted at a gas-flow rate of 13 m3/h. Important parameters, including peak voltage, chemical structures of malodorants, pulse frequency, and initial concentration, which influenced the removal efficiency, were investigated. The results showed that the mixed malodorants could be treated effectively by pulse corona. The removal efficiencies of 200 mg/m3 C2H5SH and 200 mg/m3 H2S for group 1 were 95.6% and 100%, respectively, which were almost equal to those of the two pollutants separately. The energy cost was about 65.1-81.4 J/L, which was 31.5-45.2% lower than for treating pollutants alone. The removal efficiencies of 105 mg/m3 C2HsSH and 40 mg/m3 NH3 for group 2 were 93.1% and almost 100%, and the energy cost was 65.1 J/L, 55.6% lower than that which was treated separately. In the case of two groups of mixed malodorants removal, NOx, 03, SO2, CO2, and CO were all observed. Moreover, some sulfur and white crystal ammonium nitrates were discovered adhering to the corona wires in the removal of groups 1 and 2, respectively. A dynamics model was developed to describe the relation of the removal efficiency with specific energy density and initial concentration. In the case of group 1 removal,the decomposition rate constants decreased as compared to the single treating. As for group 2 removal, the decomposition rate constants increased, especially for NH3. According to the results, the optimization design for the reactor and the matching of high pulse voltage source can be reckoned.

One of the major technological challenges for the transport sector is to cut emissions of particulate matter (PM) and nitrogen oxides (NOx) simultaneously from diesel vehicles to meet future emission standards and to reduce their contribution to the pollution of ambient air. Installation of particle filters in all existing diesel vehicles (for new vehicles, the feasibility is proven) is an efficient but expensive and complicated solution; thus other short-term alternatives have been proposed. It is well known that water/diesel (W/ D) emulsions with up to 20% water can reduce PM and NOx emissions in heavy-duty (HD) engines. The amount of water that can be used in emulsions for the technically more susceptible light-duty (LD) vehicles is much lower, due to risks of impairing engine performance and durability. The present study investigates the potential emission reductions of an experimental 6% W/D emulsion with EURO-3 LD diesel vehicles in comparison to a commercial 12% W/D emulsion with a EURO-3 HD engine and to a Cerium-based combustion improver additive. For PM, the emulsions reduced the emissions with -32% for LD vehicles (mass/km) and -59% for the HD engine (mass/ kWh). However, NOx emissions remained unchanged, and emissions of other pollutants were actually increased forthe LD vehicles with +26% for hydrocarbons (HC), +18% for CO, and +25% for PM-associated benzo[a]pyrene toxicity equivalents (TEQ). In contrast, CO (-32%), TEQ (-14%), and NOx (-6%) were reduced by the emulsion for the HD engine, and only hydrocarbons were slightly increased (+16%). Whereas the Cerium-based additive was inefficient in the HD engine for all emissions except for TEQ (-39%), it markedly reduced all emissions for the LD vehicles (PM -13%, CO -18%, HC -26%, TEQ -25%) except for NOx, which remained unchanged. The presented data indicate a strong potential for reductions in PM emissions from current diesel engines by optimizing the fuel composition.