The reduction of NO by the CO produced by incomplete combustion in the flue gas can remove CO and NO simultaneously and economically. However, there are some problems and challenges in the industrial ...application which limit the application of this process. In this work, noble metal catalysts and transition metal catalysts used in the reduction of NO by CO in recent years are systematically reviewed, emphasizing the research progress on Ir-based catalysts and Cu-based catalysts with prospective applications. The effects of catalyst support, additives, pretreatment methods, and physicochemical properties of catalysts on catalytic activity are summarized. In addition, the effects of atmosphere conditions on the catalytic activity are discussed. Several kinds of reaction mechanisms are proposed for noble metal catalysts and transition metal catalysts. Ir-based catalysts have an excellent activity for NO reduction by CO in the presence of O
2
. Cu-based bimetallic catalysts show better catalytic performance in the absence of O
2
, in that the adsorption and dissociation of NO can occur on both oxygen vacancies and metal sites. Finally, the potential problems existing in the application of the reduction of NO by CO in industrial flue gas are analyzed and some promising solutions are put forward through this review.
Carbon consumption of activated carbon varies with sulfur-containing products. In this work, differential thermogravimetric (DTG), electron paramagnetic resonance (ESR), X-ray photoelectron ...spectroscopy (XPS), and temperature programmed desorption (TPD) we re used to reveal the adsorption-regeneration process of H
2
S and the effect of adsorption products on carbon consumption. The results show that H
2
S reacts with the C=C bond to form the C-S bond as an intermediate state, followed by the formation of elemental sulfur. It directly sublimates at approximately 380 °C, about 30 °C higher than the decomposition temperature of H
2
SO
4
. In the thermal regeneration process, the elemental sulfur in the form of monoclinic sulfur (S
8
) first breaks into infinitely long chain molecules (S
∞
) and then into small molecules, finally into sulfur vapor. The desorption of elemental sulfur consumes less oxygen and carbon functional groups, reducing the chemical carbon consumption by 59.8% than H
2
SO
4
; moreover, the compressive strength reduces less due to its slight effect on the disordered graphitic structure. H
2
S also reacts with the C=O bond to form H
2
SO
3
or H
2
SO
4
. The desorption of H
2
SO
3
does not require carbon consumption. The decomposition of H
2
SO
4
needs to react with the C=C bond to release SO
2
, CO
2
, and CO, and the compressive strength of activated carbon significantly decreases. The carbon consumption originates from two aspects; the one from the regeneration of sulfur-containing products is more than twice the other one from the decomposition of oxygen-containing functional groups.
High carbon consumption is an important factor restricting the wide application of activated carbon technology for flue gas purification. A fixed-bed reactor combined with a Fourier transform ...infrared (FTIR) spectrometer was used to explore the source of carbon consumption at various SO
2
concentrations and cyclic adsorption–regeneration times. The results demonstrate that carbon consumption originates from two sources and is mainly determined by the reaction of H
2
SO
4
and C at high SO
2
concentrations and by the thermal decomposition of oxygen-containing functional groups at low SO
2
concentrations. An interesting observed phenomenon is that carbon consumption does not increase as the SO
2
concentration increases. The conversion mechanism reveals that carboxylic and anhydride groups are converted to phenol and quinone groups, which do not easily decompose with increasing SO
2
concentration. In the process of cyclic adsorption–regeneration, it is discovered that the carbon consumption in the first cycle is several times higher than that in the following cycles due to the decomposition of functional groups from the activated carbon itself. The regeneration mechanism of functional groups has been elucidated. The carboxylic acid and the phenolic hydroxyl on the surface of activated carbon are consumed in the regeneration process and formed again from the conversion of carbonyl groups in the next adsorption process under the roles of O
2
and H
2
O. It is proposed that the functional groups are regenerated in the adsorption process rather than in the regeneration process.
To decrease the operating cost of flue gas purification technologies based on carbon-based materials, the adsorption and regeneration performance of low-price semi-coke and activated coke were ...compared for SO2 and NO removal in a simulated flue gas. The functional groups of the two adsorbents before and after regeneration were characterized by a Fourier transform infrared（FTIR） spectrometer, and were quantitatively assessed using temperature programmed desorption（TPD） coupled with FTIR and acid–base titration. The results show that semi-coke had higher adsorption capacity（16.2% for SO2 and 38.6% for NO） than activated coke because of its higher content of basic functional groups and lactones. After regeneration, the adsorption performance of semi-coke decreased because the number of active functional groups decreased and the micropores increased. Semi-coke had better regeneration performance than activated coke. Semi-coke had a larger SO2 recovery of 7.2% and smaller carbon consumption of 12% compared to activated coke. The semi-coke carbon-based adsorbent could be regenerated at lower temperatures to depress the carbon consumption, because the SO2 recovery was only reduced a small amount.
To reduce chemical carbon consumption in activated coke technology used for flue gas purification, the carbon consumption mechanism of commercial activated coke in the presence of water vapor was ...studied. A fixed-bed reactor and a Fourier transform infrared (FTIR) spectrometer were combined to study the amount of carbon consumption. Temperature-programmed desorption (TPD) coupled with in situ diffuse reflectance infrared Fourier transform (in situ DRIFT) spectra were used to investigate functional group changes of activated coke. The sources and factors influencing carbon consumption in various adsorption atmospheres and in the N
2
regeneration atmosphere were compared. Carbon consumption during the adsorption and regeneration process was mainly due to the release of C–O and C=C groups. The addition of H
2
O increased the formation of carbonates and carboxylic acids during the adsorption process, which decomposed during the regeneration process, thereby increasing carbon consumption. Carbon consumption was reduced during regeneration in an H
2
O-SO
2
adsorption atmosphere, mainly because of the formation of C–S bonds, which reduced the formation of CO
2
. The C–N bonds generated in an H
2
O-NO adsorption atmosphere were decomposed during the regeneration process, thereby increasing carbon consumption. In a complex atmosphere of SO
2
, NO, NH
3
, and H
2
O, SO
2
was absorbed by NH
3
, and the amount of carbon consumption was consistent with that in the NO atmosphere during the regeneration process. The total carbon consumption in various adsorption atmospheres ranged from 85.4 to 125.2 μmol/g. Compared with an anhydrous atmosphere, chemical carbon consumption increased by 6.5–14.3% in the presence of H
2
O. Chemical carbon consumption was reduced by decreasing the H
2
O concentrations, which provides a reference concept for reducing the operating cost of the activated coke process in industry.
Accurately estimating the reservoir evaporation loss is crucial for water resources management. The existing research on reservoir evaporation loss estimates primarily focuses on large spatiotemporal ...scales and neglects the rapid dynamic changes to reservoirs’ surface area. For reservoirs essential for frequent flood control and regular water supply, high spatiotemporal evaporation data are crucial. By integrating remote sensing and the evaporation model, this study proposes a new method for the high spatiotemporal estimation of the evaporation losses from reservoirs. The proposed method is applied to the largest artificial freshwater lake in Asia, i.e., Danjiangkou (DJK) Reservoir. The daily reservoir water surface area is extracted at a spatial resolution of 30 m during the period 2014–2018 based on the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM). The daily evaporation rate is estimated at a spatial resolution of 100 m using the generalized complementary relationship (GCR). The results show that the water surface area of the DJK Reservoir exhibits rapid and frequent fluctuations from 2015 to 2018, with a multi-year average area of 731.9 km2 and a maximum and minimum difference of 304 km2. Significant seasonal variations are observed in both the evaporation rate and volume, with a multi-year average evaporation rate of 806 mm and evaporation volume of 595 million m3. The estimated results align well with three other independent estimates, indicating that the GCR is capable of water surface evaporation estimation. Further analysis suggests that the data resolution has a great influence on the evaporative water loss from the reservoir. The estimated mean annual evaporation volume based on the 1000 m resolution water surface area data is 14% lower than that estimated using the 30 m resolution water surface area data. This study not only provides a new method for the high spatiotemporal estimation of reservoir evaporation by integrating remote-sensing data and the GCR method but also highlights that reservoir evaporation water loss should be quantified using the volume rather than the rate and that the estimated loss is noticeably affected by the estimation spatial resolution.
To improve the denitrification efficiency for the selective catalytic reduction of NO with NH
3
in the flue gas purification process, a low-rank activated coke (AC) was treated with ammonia (NH
3
·H
...2
O) solution or nitric acid (HNO
3
) solution to increase the content and type of nitrogen-containing functional groups, and then the role of nitrogen-containing functional groups in the reduction of NO was analyzed. The modified AC samples were characterized by N
2
adsorption/desorption to determine the pore structures and by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy to detect the surface functional groups. After modification, the content of oxygen-containing functional groups on the AC surface increased, including quinone, lactone and carboxyl, which are favorable for SO
2
adsorption. Meanwhile, the type and content of nitrogen-containing functional groups on the AC surface changed; these groups fall into two categories: active groups and non-active groups. Before and after the denitrification process, the regular changes in the content of active and non-active groups showed that the active groups with pyrrole-like or pyridine-like structures can promote NO adsorption and then strengthen the denitrification. On the other hand, active groups may be reduced by NH
3
or oxidized by O
2
, referring to side reactions, to generate non-active groups such as nitro, nitrate, amine and imine. More importantly, the role of nitrogen-containing functional groups was identified in the denitrification process. This chemical modification method is effective for improving the performance of low-cost AC since the employed chemicals are commercially available.
Graphical Abstract
NOx, COx, and volatile organic compounds (VOCs) widely exist in motor vehicle exhaust, coke oven flue gas, sintering flue gas, and pelletizing flue gas. Potassium species have an excellent promotion ...effect on various catalytic reactions for the treatment of these pollutants. This work reviews the promotion effects of potassium species on the reaction processes, including adsorption, desorption, the pathway and selectivity of reaction, recovery of active center, and effects on the properties of catalysts, including basicity, electron donor characteristics, redox property, active center, stability, and strong metal-to support interaction. The suggestions about how to improve the promotion effects of potassium species in various catalytic reactions are put forward, which involve controlling carriers, content, preparation methods and reaction conditions. The promotion effects of different alkali metals are also compared. The article number about commonly used active metals and promotion ways are also analyzed by bibliometric on NOx, COx, and VOCs. The promotion mechanism of potassium species on various reactions is similar; therefore, the application prospect of potassium species for the coupling control of multi-pollutants in industrial flue gas at low-temperature is described.
A carbonyl sulfide (COS) hydrolysis catalyst can play an efficient role in blast furnace gas (BFG), but the life of the catalyst is greatly shortened due to the presence of O2 and H2S in the ...atmosphere, so improving the sulfur resistance of the catalyst is the key to application. In this work, alkali metals Na and K modified γ-Al2O3 catalysts to improve COS hydrolysis efficiency and sulfur resistance by adding an alkaline center. Compared with γ-Al2O3 catalysts, the COS hydrolysis efficiency of the modified catalysts in the experiment was improved by 12% in the presence of H2S and O2. The main cause of catalyst sulfur poisoning is the presence of O2, which intensifies both the total amount of sulfur deposition and the proportion of sulfate. It is found that the NaOH/Al2O3 catalyst shows better sulfur resistance than the KOH/Al2O3 catalyst for two reasons: first, the support of Na can significantly improve the medium-strong alkaline site, which is the adsorption site of H2S. This is equivalent to increasing the “sulfur capacity” of H2S adsorption and reducing the impact of sulfur deposition on the main reaction. Second, the elemental sulfur is more easily produced on the NaOH/Al2O3 catalyst, but the sulfur is further oxidized to sulfate and sulfite on the KOH/Al2O3 catalyst. The molecular diameter of elemental sulfur is smaller than that of sulfate. Therefore, the NaOH/Al2O3 catalyst has better sulfur resistance.
The complete chloroplast genome sequence of Artocarpus nanchuanensis was determined, an Endangered species of Artocarpus in the family Moraceae. The plastome is 160,752 bp in length, exhibiting a ...characteristic quadripartite structure with a pair of inverted repeat regions (IRs) of 25,693 bp, separated by a large single-copy region (LSC) and a small single-copy region (SSC) of 89,345 bp and 20,021 bp, respectively. Further, the maximum likelihood phylogenetic analysis was conducted using 24 complete plastomes of the Moraceae and Cannabaceae, which supports the close relationship between Artocarpus and Morus.
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