Efficiency Of NO Research Articles

Simultaneous removal of SO2, NOx and Hg0 by O3 oxidation integrated with bio-charcoal adsorption

Simultaneous removal of SO2, NOx and Hg0 using O3 and corn stalk bio-charcoal (CR)/coconut shell activated carbon (CS) was compared in a fixed bed. The effects of temperature, adsorption time and ratio of O3/NO on the removal efficiency of NO, Hg0 and SO2 by CR/CS were studied, and the CR and CS was characterized and analyzed. The results indicated that the oxidation rate of NO and Hg0 increased with the increase of O3/NO ratio, while the oxidation rate of SO2 first increased and then decreased slightly. The increase of temperature inhibits the oxidation of NO but promotes the oxidation of Hg0 and SO2. At 140°C and O3/NO ratio was 1.4, the oxidation rate of NO, Hg0 and SO2 is 99%, 78.6% and 3.5%, respectively. As O3/NO ratio increased from 0.4 to 1.4, the removal efficiency of CR for NOx increased from 4.6% to 93%, and CS increases from 4.5% to 79%. CR and CS can reduce part of NO2 and increase NO concentration at the outlet. NOx adsorption performance on CR is relatively better, while those of Hg0 and SO2 on CS are relatively stronger. CS has stronger physical adsorption capacity than CR. The relative content of oxygen-containing functional groups C-O and C=O on the surface of CR is higher than that of CS, while its relative content of COOH and O=C-O is lower.

Pore Structure Analysis to Adsorb NOx Gas based on Porous Materials

We studied the adsorption of nitrogen oxides according to various porous materials room temperature, which can effectively to adsorb the nitrogen oxides. Based on results of measuring NOx concentration, the activated carbon materials have been shown to adsorb NOx well, and they have been shown to more efficiently removing NO2, which is very harmful to the environment. In particular, in the case of the coconut activated carbon, the removal efficiency of NO and NO2 was very excellent, and the removal rate of was 30% for 100 minutes and 19.5% for 840 minutes. Our measurement results confirmed that the activated carbon materials have a very large specific surface area and pore volume. In addition, the coconut activated carbon appears to have a large specific surface area and pore volume to remove NOx over a long period of time. Based on the experimental results, it is expected to be used as a material that efficiently removes nitrogen oxides at room temperature.

Highly efficient MnOx/biochar catalysts obtained by air oxidation for low-temperature NH3-SCR of NO

In this study, a novel air oxidation treatment strategy was proposed to modify Mn-doped biochar catalysts for enhanced removal of NO at low temperature. The pre-oxidation at 400 °C and post-oxidation at 250 °C under air atmosphere was applied respectively before and after impregnating biochar with Mn-containing solution (BC-OMO). The results showed that, after pre-oxidation the specific surface area and total pore volume of the sample increased to 734 m2/g and 0.440 cm3/g respectively in comparison with those without pre-oxidation (557 m2/g and 0.353 cm3/g). After further post-oxidation, the contents of Mn4+ and chemisorbed oxygen (Oα) in BC-OMO increased to 36.2% and 49.8% respectively from those without air oxidation (25.4% and 38.7%), which could enhance the surface acidity and redox capabilities of the catalysts. The denitration results showed that the conversion efficiency of NO for BC-OMO catalyst reached as high as 97.0% at 150 °C, which was significantly higher than that without air oxidation (61.8%). The mechanisms for improving denitration efficiency of MnOx/biochar catalysts by pre- and post-air oxidation were also discussed.

Effects of system parameters and residual ions on the oxidation removal of NO by Fenton method.

In the present work, the effects of relevant system parameters on the oxidation removal of NO using the Fenton method were discussed in detail. Moreover, the impacts of ions remaining in the coal-fired process on the NO oxidation efficiency were investigated specifically. The experimental results showed that the oxidation efficiency of NO decreased with the increase of gas flow rate, reagent temperature, and CO2 volume fraction in the evaluated range, while it increased first and then decreased with the increase of gas temperature, NO initial concentration, O2 volume fraction, initial pH of reagent, and Fe2+/H2O2 molar ratio. In addition, the corresponding impact mechanism of the system parameters was discussed respectively. Although the SO2 showed a competitive effect on the utilization of oxidative radicals, the Fenton system also showed an ability for simultaneous removal of NO and SO2. Furthermore, the results indicated that the NO oxidation efficiency would be influenced by the residual ions, such as Ca2+, Mg2+, Na+, SO42-, and Cl-. The presence of the mentioned ions showed an inhibiting effect on the oxidation removal of NO in the first few minutes, while the NO oxidation efficiency would be enhanced in the bulk stage of the tests. The positive effect trended to be more obvious with the decline of the ion dosage. Subsequently, the influence mechanism of the aforesaid residual cations and anions was supposed and proposed preliminarily.

Bioaugmentation of two-stage aerobic sequencing batch reactor with mixed strains for high nitrate nitrogen wastewater treatment

Mixed strains Delftia sp.YH01 and Acidovorax sp.YH02, with capability of heterotrophic nitrification-aerobic denitrification, were introduced into a two-stage aerobic sequencing batch reactor to enhance NO 3 − -N removal. With optimal C/N of 8, efficient NO 3 − -N removal was achieved at initial NO 3 − -N concentration of 2000 mg·L −1 . Meanwhile, the massive accumulation of NO 2 − -N was avoided during the long operation. Compared to the one-stage aerobic sequencing batch reactor, the removal efficiency of NO 3 − -N and TN in the two-stage aerobic sequencing batch reactor was increased by 36.5% and 42.7%, which respectively was 93.8% and 88.4%. Microbial community study showed that the mixed strains have the stronger viability and can synergistically denitrify with the indigenous microorganisms in system, such as Azoarcus, Uncultured Saprospiraceae, Thauera, Paracocccus , which could be major contributors for aerobic denitrification. The proposed technology was shown to achieve high-efficiency treatment of high NO 3 − -N wastewater through aerobic denitrification.

NO Separation Characteristics in Integrated Electromigration Membrane Reactor

An integrated electromigration membrane absorption method has been proposed for the separation of NO from simulated mixed gas. The experiments were conducted to investigate the effect of discharge voltage, gas flow rate, inlet concentrations, and absorbents on the NO separation efficiency and total mass transfer coefficient in the integrated electromigration membrane reactor. The experimental results demonstrated that the NO separation efficiency and total mass transfer coefficient increased with the increase in the applied discharge voltage of the integrated electromigration membrane reactor. Regardless of discharge or not, the separation efficiency of NO continuously decreased with the increase in the gas flow rate and inlet concentration of NO in the experimental process. The total mass transfer coefficient of NO increased first and then decreased with an increase in the gas flow rate, while it decreased with an increase in NO inlet concentration. Compared with the membrane absorption without discharge voltage under the condition tested, at a discharge voltage of 18kV, the NO separation efficiency and the total mass transfer coefficient increased by 48.7% and 9.7 times, respectively.

A novel combined system using Na2S2O8/urea to simultaneously remove SO2 and NO in marine diesel engine exhaust

The novel combined system using Na2S2O8/urea was used to simultaneously absorb nitric oxide and sulfur dioxide emissions from marine diesel engines as well as inhibit the formation of nitrate in cleaning wastewater to meet the increasingly stringent requirements of regulations. The influences of reaction temperature, Na2S2O8 concentration, urea concentration, SO2 concentration, NO concentration and pH value on SO2 removal efficiency, NO removal efficiency and nitrate concentration were investigated. The experimental results showed that different reaction temperatures had different influences on SO2 removal efficiency, NO removal efficiency and nitrate concentration. An increase in Na2S2O8 could improve the absorption of NO. The addition of urea could effectively improve the removal efficiency of NO and reduce the nitrate concentration. The removal efficiencies of 1000 ppm NO and 1000 ppm SO2 achieved 100 % with 0.2 mol/L Na2S2O8 and 2 mol/L urea at 70℃, and the nitrate content was 8.56 mg/L which was far lower than the regulatory requirement of 60 mg/L. The acidic condition (pH ≤ 5.5) not only facilitated the absorption of NO but also reduced the generation of nitrate. According to the experimental results, the novel combined system was promising to be applied to the control technology of marine diesel engine exhaust.

Direct conversion of NO and SO2 in flue gas into fertilizer using ammonia and ozone

This study focused on the simultaneous removal of NO and SO2 from an industrial flue gas stream. To evaluate the removal efficiency of NO and SO2 using O3 and NH3, the consumption of two reactants (O3 and NH3) in line with the conversion of NO and SO2 was quantified experimentally. In addition, NO and SO2 were converted to valuable fertilizers, NH4NO3 and (NH4)2SO4. To identify a principle strategy to enhance the generation of fertilizer, Fourier transform infrared spectroscopy was used to examine the reaction mechanisms for the formation of NH4NO3 and (NH4)2SO4. Acceleration of SO2 oxidation could be achieved effectively by adding NO to a gas mixture of SO2, NH3, and O3. The formation of HNO3 might be enhanced by the simultaneous feeding of NO and SO2. Particle generation was also 10 times higher for NH3/(NO + SO2) than for NH3/NO and for NH3/SO2, which is a prominent feature of this study. Moreover, the introduction of steam had a positive influence on particle generation. This method offers dual applications for NO and SO2 removal from a flue gas stream and direct fertilizer generation.

Study on the Performance of NTP with Wood Fiber in NO Removal

The increase of diesel vehicle leads to a large amount of NO emissions, and non-thermal plasma (NTP) combined with wood fiber is a new method in the field of exhaust gas purification. In this paper, the effects of NTP combined with different kinds of wood fibers and without wood fibers on the removal of NO were compared, and the optimal purification efficiency of NO was determined by experiments under different application conditions. The experimental results show that the NO conversion efficiency of NTP combined with wood fiber is better than that of NTP or wood fiber alone, among which NTP combined with scotch pine has the highest conversion efficiency. Through the analysis of the mechanism of NO conversion by wood and NTP, the effects of different conditions on NO conversion were obtained. The trend of NO removal with voltage/frequency indicates that the increase of voltage and frequency can promote the removal of NO. The increase of humidity also promoted the removal of NO, but when the humidity exceeded 25%, the conversion of NO decreased slightly. And the filling rate of 0.3 is the best value for NO conversion. Although NO cannot be completely purified by this method, there is still a higher conversion efficiency under the condition of low temperature and no catalyst. It can be proved that NTP bonded wood fiber is a new way to remove NO.

NOx removal efficiency of urban photocatalytic pavements at pilot scale

Photocatalytic technology implemented in construction materials is a promising solution to contribute to alleviate air quality issues found in big cities. Photocatalysis has been proved able to mineralise most harmful contaminants. However, important problems associated with monitoring the efficiency of these solutions under real conditions still remain, including the lack of affordable analytical tools to measure NOx concentrations with enough accuracy. In this work, two pilot scale demonstration platforms were built at two different locations to assess the photocatalytic NOX removal efficiency of ten selected materials exposed outdoors for AQmesh low-cost sensor PODs were used to measure ground-level to measure NO and NO2 concentrations during nearly one year. The pollutant removal efficiency of the materials was then calculated based on a comparison with simultaneously concentration measurements carried-out on reference, non-active materials. It was found that the NO2 removal efficiency presented large variations across the seasons, with maxima during the warmer months, while NO efficiencies were comparatively steadier. Statistical analysis delivered evidence that the efficiencies significantly depend on different meteorological variables (irradiance and relative humidity) besides NO, NO2 ambient concentrations. Lower efficiencies were observed for higher concentration levels and vice versa. The influence of water vapour could be related to two different effects: a short-term contribution by the instantaneous air humidity and a long-term component associated with the hygroscopic state of the material. The contribution of wind to the pollutant removal efficiencies was principally related to the humidity of air masses moving above the location and to the advection of pollutants from specific emission sources.

Interaction between SO2 and NO in their adsorption and photocatalytic conversion on TiO2

The simultaneous adsorption and photocatalytic conversion of SO2 and NO on P25–TiO2 were studied. In particular, the interaction of SO2 and NO on each other’s adsorption and photocatalytic oxidation was discussed. The adsorption of NO on P25 was negligible when comparing to that of SO2, while with the coexistence of NO and SO2 in flue gas, both the adsorption of SO2 and NO were improved. In the presence of water and oxygen, the photocatalytic oxidation efficiency of NO with an efficiency of >69% was observed on irradiated TiO2 surface, which lasted for at least 1000 min. Oxygen was found to have much more important effect than water on the photocatalytic oxidation of NO. In the presence of SO2 however, the photocatalytic process of NO was largely reshaped. The whole process was controlled by the photocatalytic oxidation of SO2. A dramatic efficiency decease (breakthrough of the catalyst bed) was observed for both NO and SO2 due to the catalyst deactivation caused by the poisoning of SO2 oxidation products. Before the breakthrough, the photocatalytic conversion efficiency of NO increased with increasing the SO2 concentration, which was mainly due to the improved NO adsorption in the presence of SO2.

Removal of high concentration of nitrate and phosphate from aqueous mixotrophic solution by Chlorella vulgaris

Microalgae exhibit large potential as an alternative to advanced biological nutrient removal in wastewater or simulated wastewater at laboratory conditions. Therefore, it is necessary to determine the optimum conditions for nutrient removal. This study investigated the total carbohydrate, chlorophyll-a, -b, carotenoid and lipid production and nutrient removal of mixotrophic microalgae ( C. vulgaris ) cultured in different nitrate/phosphate rich modified BG-11 medium (0-200 mg L -1 ) at longer growth periods (10 days). The mean removal efficiency of NO 3 -N (in nitrate source), and PO 4 -P (in phosphate source) (88.29 ±0.12 and 31.06 ±0.22%, respectively) was reached in the mixotrophic culture. Under the optimum conditions (200 µmol photon m⁻ 2 s⁻ 1 16 h photoperiod and 28% inoculum size), 63.61-99.05% of NO 3 - and 13.97-63.77% of PO₄ 3 ⁻were successfully removed. The lipid and carbohydrate productivities were 27.95 and 29.53 g L −1 d −1 , 0.2869 and 0.2435 g L -1 d -1 respectively, which were approximately 9-12 times higher than those in photoautotrophic condition. The BG-11 growth media containing 10 g L −1 glucose and excessive amount of nutrient effect results indicate that the Chl-a, -b and carotenoid contents of C. vulgaris is higher at 100 mg L -1 N and 50 mg L -1 P growth media composition compared to 100% growth media composition. Thereby, the findings of this study provided an insight into the role of algal uptake of nutrients under the nutrient rich mixotrophic medium for the future algae-based treatment application.

Simultaneous Removal of NOx and SO2 by MgO Combined with O3 Oxidation: The Influencing Factors and O3 Consumption Distributions

Simultaneous removal of NOx and SO2 by MgO combined with O3 oxidation was studied. The effects of the O3/NO molar ratio, oxidation temperature, and oxidation residence time on N2O5 decomposition and O3 consumption distributions were systematically illustrated, which is of great significance for improving NOx removal efficiency and reducing O3 consumption in practical application. When the O3/NO molar ratio was greater than 1.0, the highest N2O5 yield was achieved at 90 °C. The NOx removal efficiency reached 96.5% at an O3/NO molar ratio of 1.8. The oxidation temperature increased from 90 to 130 °C, resulting in the decrease of N2O5 yield, the improvement of O3-ICC (O3 invalid cycle consumption) caused by N2O5 decomposition, and the decrease of NOx removal efficiency from 96.5 to 76%. Besides, the effects of pH, SO2 concentration, and MgSO3 addition on NOx removal efficiency were also investigated. The results showed that the removal efficiency of NOx decreased with the increase of SO2 concentration, while MgSO3 addition into MgO slurry could promote the absorption of NO2 due to the reaction between NO2 and SO32–.

Effect of critical dual-carrier structure parameters on performance enhancement of a dual-carrier catalytic converter and the gasoline engine system

The high NO2 concentrations in the gasoline engine exhaust gas are beneficial to improve the regenerative equilibrium performance of the catalytic particulate filter regeneration system. In this work, the effect of critical dual-carrier structure parameters on NO conversion efficiency of the dual-carrier catalytic converter is explored by using the numerical simulation method. The reliable operating temperature range of the dual-carrier catalytic converter under critical dual-carrier structure parameters and the distribution of NO and NO2 mass fraction under the equilibrium state of the catalytic reaction are analyzed. Based on GT-Power software, the variation law of the brake specific fuel consumption (BSFC) and power is studied. The main results are presented as follows: The maximum conversion efficiency of NO is increased from 63% to 67% when the dual-carrier cell density ratios are increased from 300 cpsi/400 cpsi to 500 cpsi/400 cpsi. The maximum NO conversion efficiency of NO is increased from 64% to 66% when the dual-carrier wall thickness ratios are decreased from 0.24 mm/0.17 mm to 0.10 mm/0.17 mm. The maximum conversion efficiency of NO remains about 65% when the dual-carrier length ratios are increased from 30 mm/70 mm to 70 mm/30 mm. The maximum conversion efficiency of NO is increased from 58.5% to 74% when the carrier diameter is increased from 80 mm to 120 mm. And after optimization, the BSFC of the gasoline engine system is reduced by 2% while the power is increased by 7.2%. Finally, some guidelines are proposed to reduce the BSFC and increase the power of the gasoline engine system, while improving the NO conversion efficiency of the dual-carrier catalytic converter.

Simulation and experimental study of the NOx reduction by unburned H2 in TWC for a hydrogen engine

The unburned H2 can be used to reduce NO emission in conventional TWC (three-way catalyst) for a hydrogen internal combustion engine when it works at equivalence ratio marginally higher than the stoichiometric ratio. To explore the effects and feasibility of this reaction, a Perfectly Stirred Reactor simulation model of TWC has been built with simplified mechanisms. Experiments on a 2.3 L turbocharged hydrogen engine are used to verify the conclusion. It shows that rising initial temperature accelerates the reduction of NO and the maximum reaction rate occurs at 400 °C temperature. The conversion efficiency of NO remains approximately 0 when temperatures below 300 °C. The efficiency reaches a peak value of approximately 98% with 400 °C and declines gradually. The unburned H2 to NO mixing ratio greater than 1.5 in TWC guarantees 100% NO conversion efficiency. The experiments indicate that the NOx concentration decreases from 2056 ppm to 41 ppm at the stoichiometric ratio after the treatment of TWC and NOx reaches 0 ppm with a rich ratio. Results also demonstrate that the suitable reaction temperatures for TWC locate in the range of 400 °C–500 °C. Therefore, if the temperature and the mixing ratio are appropriate, it can achieve zero emissions with NOx reduction by unburned H2 in conventional TWC for a hydrogen engine.

Interaction among the simultaneous removal of SO2, NO and Hg0 by electrochemical catalysis in K2S2O8

Sulfur dioxide (SO2), nitrogen oxides (NOx) and mercury (Hg0) produced by coal combustion are still the main sources of atmospheric pollutants. To find out the interaction among the simultaneous removal of SO2, NO and Hg0, the method of electrochemical catalysis in K2S2O8 was used to oxidize and remove these three pollutants from the simulated flue gas. Results indicated that the presence of SO2 promoted the oxidative absorption of NO under the condition of sufficient oxidant, while NO showed a weak competitive oxidation relationship to SO2. SO2 promoted the oxidative absorption of Hg0 through the generated SO32−, and Hg0 had no obvious effect on the desulfurization process due to its low concentration. NO promoted the oxidative absorption of Hg0 by its oxidation product NO2, and Hg0 also had no significant effect on the denitrification process due to the low concentration. During the removal of SO2, NO and Hg0 by electrochemical catalysis in K2S2O8, the electrochemical method could not only promote the rapid decomposition of S2O82− to produce a large amount of SO4−, but also help the electrolysis of H2O into HO. The oxidation of the solution was enhanced by oxidative free radicals such as SO4− and HO. Thus, the removal efficiency of SO2 oxidized by electrochemically catalyzed K2S2O8 was as high as 96%, the removal efficiency of NO could reach 90%, and the Hg0 removal efficiency was up to 92%.

Promoting Effect of H+ and Other Factors on NO Removal by Using Acidic NaClO2 Solution

In this study, NaClO2 was selected as a denitration oxidant. In order to clarify the mechanism of NaClO2 as an oxidation agent for NO removal efficiency, the effects of H+ and other factors (NaClO2 concentration, temperature, and the other gas) on the NO removal efficiency were investigated. NaClO2 showed a promotional ability on NO removal, whose efficiency increased with the increase of NaClO2 concentration. One hundred percent removal efficiency of NO could be achieved when the NaClO2 concentration was 0.014 mol/L. Furthermore, raising the reaction temperature benefited the removal of NO. The lower the pH, the better the NO removal efficiency. The promoting effect of H+ on the NO removal was studied by the Nernst equation, ionic polarization, and the generation of ClO2. Under the optimal conditions, the best removal efficiency of NO was 100%. Based on the experimental results, the reaction mechanism was finally speculated.

Effect of post-treatment on the selective catalytic reduction of NO with NH3 over Mn3O4

The Mn3O4 nanocrystals were successfully prepared by rapid precipitation method at room temperature from MnSO4, H2SO4 and NH3•H2O, and the influences of post‒treatment temperatures at 200‒500 °C on texture, morphology, crystal face, redox and the selective catalytic reduction of NO with NH3 were investigated. The results show that a single tetragonal phase of Mn3O4 nanocrystals is obtained after dryness and it has a BET surface area of 112 m2/g and exposes the (101) plane. When the post‒treatment temperature increases from 200 to 400 °C, both crystal phase and crystallite sizes of Mn3O4 are almost unchanged, but their main exposed crystal faces change from (101) to (200) and (112). When the post‒treatment temperature increases to 500 °C, Mn2O3 is dissociated from Mn3O4. Mn3O4_300 possesses a developed pore structure with a SBET of 201 m2/g and a pore volume of 0.41 cm3/g. Mn3O4_400 has low reduction peaks at 210 and 467 °C and similar reduction properties after multi‒reaction of NH3‒SCR, but the peak temperature shifts to higher temperature compared to the fresh sample. When the post‒treated sample is applied to the NH3‒SCR reaction, Mn3O4_400 exhibits excellent NO removal efficiency at low temperatures, which may be related to the surface oxidation of Mn3O4 to promote the formation of NO2. Mn3O4_400 has good resistance of SO2 and has 92% removal efficiency of NO when only SO2 is induced in the simulated gas, but NO removal efficiency decreases to 63% in the presence of H2O and SO2 due to the generation of MnSO4•H2O.

Key role of NO + C3H8 reaction for the elimination of NO in automobile exhaust by three-way catalyst.

Pd-only three-way catalysts with improved catalytic activity for NO elimination were prepared. In order to explore the catalytic reaction rules of NO reduction under a three-way catalytic system, a series of single reactions related to NO reduction were evaluated. It was found that the reaction temperatures of NO + H2 or NO + CO or NO + C3H6 reactions were below 250°C, while that of NO + C3H8 was up to 350°C. Thus, the reaction NO + C3H8 served as the key reaction in determining the purification efficiency of NO at the high-temperature stage. By in situ FTIR, we proposed that three possible steps were involved in NO + C3H8 reaction. The first step was the oxidation of C3H8 and NO to acetone and nitrate species by active oxygen species, respectively (C3H8 + O* → C3H6O, NO + O* → NO3-). XPS results revealed that the amount of active oxygen species in Pd/CeO2-ZrO2-Al2O3 (Pd/CZA, 73.7%) was much higher than that in Pd/CexZr1-xO2+Al2O3 (Pd/CZ+A, 64.1%). This was in line with the higher reaction efficiency of the first step over Pd/CZA. Then the NO + C3H8 reaction was accelerated by the first step, which consequently contributed to the higher NO elimination efficiency of Pd/CZA.

Simultaneous removal of nitrogen oxides and sulfur dioxide using ultrasonically atomized hydrogen peroxide.

A new method was developed for denitrification and desulfurization using hydrogen peroxide with the aid of an ultrasonic nebulizer to obtain high removal efficiency of NOx and SO2. Comparing with the atomizing nozzles having the aperture size of 0.01~0.02mm, the droplets generated using the ultrasonic nebulizer show the smallest d50 value of 7.2μm, with 72% possessing the size less than 10μm. Based on the numerical simulation of the vaporization rate of droplets, it is indicated that the droplets with the size of 7.2μm can be vaporized totally at very short residence time (0.11s) under 130°C. Effects of influence factors including the reaction temperature, the initial H2O2 concentration, pH value, and the flue gas flow rate were studied on the removal efficiencies of NO and SO2. Using the in-series double-oxidation subsystems with H2O2 concentration of 6wt%, pH5.0, and the reaction temperature of 130°C, the removal efficiencies of SO2 and NO are respectively 100% and 89.3% at the short residence time of 1.8s, and the removal efficiency of NO can be increased to 100% as the residence time is longer than 3.7s. It is confirmed that the ultrasonically atomized H2O2 can indeed enhance the removal efficiencies of NO and SO2 at the optimal temperature, owing to the fast vaporization rate of fine droplets as well as the formation of more active radicals to be captured by NO and SO2 simultaneously. The results here provide a promising route to remove effectively the emissions of NO and SO2 simultaneously. Graphical abstract.