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The introduction of enlarged and interconnected nanochannels into metal–organic frameworks (MOFs) overcome their micropore size restriction, enhances mass transportation, and improves the accessibility of anchored metal clusters. Herein, foamed Ce‐MOF single crystals (F‐Ce‐MOF‐SC‐x) designed from a multiscale co‐assembly is reported in the presence of a copolymer template and 1,3,5‐trimethylbenzene as a structural regulator. The resultant F‐Ce‐MOF‐SC‐x possessed well‐defined microporous tandem‐ordered meso‐macroporous foams with superior connectivity and versatile Ce‐defective unsaturated sites (Ce‐DUS). F‐Ce‐MOF‐SC‐x is applied as a stable carrier for anchoring polytertiary amines (PA) via coordination interactions with Ce‐DUS. Owing to the superior ability of PA to recognize SO2, the resultant F‐Ce‐MOF‐SC‐x@yPA delivers exceptional performance in terms of the high‐temperature reversible adsorption and separation of SO2, including a remarkable capacity for SO2, spectacular selectivity for SO2/CO2/N2, an ultrafast adsorption equilibrium rate, and stability for 50 cycles. These characteristics are outstanding among those of MOFs and superior to those of many reported SO2 adsorbents. [ABSTRACT FROM AUTHOR]

The design of novel materials for sulfur dioxide (SO2) capture and conversion with considerable efficiency under mild conditions is of great significance for human health and environmental protection yet highly challenging. Herein, we report a series of triazine‐based multicomponent metallacages via coordination‐driven self‐assembly of 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine, cis‐Pt(PEt3)2(OTf)2 and different tetracarboxylic ligands. As the increase of the length of the tetracarboxylates, the structures of the metallacages change from pyramids to extended octahedrons. Owing to their N‐rich structure, these metallacages are further used for selective SO2 capture, showing good adsorption capacity and remarkable SO2/CO2 selectivity in ambient conditions, suggesting their potential applications toward real flue gas desulfurization. The metallacages are further employed for the conversion of SO2 into value‐added compounds, showing exceptional efficiency even dilute SO2 is used as the reactant. This study represents a type of structure‐tunable triazine‐based metallacages for SO2 capture and conversion, which will pave the way on the applications of metal‐organic complexes for gas adsorption. [ABSTRACT FROM AUTHOR]

SO2 (sulfur dioxide) is a toxic substance emitted into the environment due to burning sulfur-containing fossil fuels in cars, factories, power plants, and homes. This issue is of grave concern because of its negative effects on the environment and human health. Therefore, the search for a material capable of interacting to detect SO2 and the research on developing effective materials for gas detection holds significant importance in the realm of environmental and health applications. It is well known that one of the effective methods for predicting the structure and electronic properties of systems capable of interacting with a molecule is a method based on quantum mechanical approaches. In this work, the DFT (Density Functional Theory) program DMol3 in Materials Studio was used to study the interactions between the SO2 molecule and four systems. The adsorption energy, bond lengths, bond angle, charge transfer, and density of states of SO2 molecule on pristine graphene, N-doped graphene, Ga-doped graphene, and -Ga-N- co-doped graphene were investigated using DFT calculations. The obtained data indicate that the bonding between the SO2 molecule and pristine graphene is relatively weak, with a binding energy of −0.32 eV and a bond length of 3.06 Å, indicating physical adsorption. Next, the adsorption of the molecule on an N-doped graphene system was considered. The adsorption of SO2 molecules on N-doped graphene is negligible; generally, the interaction of SO2 molecules with this system does not significantly change the electronic properties. However, the adsorption energy of the gas molecule on Ga-doped graphene relative to pristine graphene increased significantly. The evidence of chemisorption is increased adsorption energy and decreased adsorption distance between SO2 and Ga-doped graphene. In addition, our results show that introducing -Ga-N- co-dopants of an "ortho" configuration into pristine graphene significantly affects the adsorption between the gas molecule and graphene. Thus, this approach is significantly practical in the adsorption of SO2 molecules. [ABSTRACT FROM AUTHOR]

Abstract The design of novel materials for sulfur dioxide (SO2) capture and conversion with considerable efficiency under mild conditions is of great significance for human health and environmental protection yet highly challenging. Herein, we report a series of triazine‐based multicomponent metallacages via coordination‐driven self‐assembly of 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine, cis‐Pt(PEt3)2(OTf)2 and different tetracarboxylic ligands. As the increase of the length of the tetracarboxylates, the structures of the metallacages change from pyramids to extended octahedrons. Owing to their N‐rich structure, these metallacages are further used for selective SO2 capture, showing good adsorption capacity and remarkable SO2/CO2 selectivity in ambient conditions, suggesting their potential applications toward real flue gas desulfurization. The metallacages are further employed for the conversion of SO2 into value‐added compounds, showing exceptional efficiency even dilute SO2 is used as the reactant. This study represents a type of structure‐tunable triazine‐based metallacages for SO2 capture and conversion, which will pave the way on the applications of metal‐organic complexes for gas adsorption.

In this study, fly ash was modified with NaOH and Ca(OH)2 and discussed the feasibility of its adsorption of SO2 from flue gas in electrostatic precipitator (ESP). The optimal modification conditions were determined by comparing the changes of SO2 adsorption performance of different modified fly ashes in flue gas. The effect of modification and adsorption of SO2 before and after on the electrical conductivity of fly ash was investigated by testing the specific resistance characteristics. The results showed that when the solid–liquid ratio was 1:5 and the modification time was 90 min, the Ca(OH)2 modified fly ash has the best adsorption capacity for SO2 in flue gas, and the adsorption capacity of SO2 was 31.44 mg/g. Compared with the raw fly ash, the adsorption capacity increased by 141.85%. The modified fly ash has better conductivity than that before modification, and the peak-specific resistance can be reduced by two orders of magnitude. After SO2 adsorption, the specific resistance of alkali modified fly ash was increased, but it was still lower than that of the raw fly ash, which was favorable to be removed in the dust removal stage. [ABSTRACT FROM AUTHOR]

SO2 (sulfur dioxide) is a toxic substance emitted into the environment due to burning sulfur-containing fossil fuels in cars, factories, power plants, and homes. This issue is of grave concern because of its negative effects on the environment and human health. Therefore, the search for a material capable of interacting to detect SO2 and the research on developing effective materials for gas detection holds significant importance in the realm of environmental and health applications. It is well known that one of the effective methods for predicting the structure and electronic properties of systems capable of interacting with a molecule is a method based on quantum mechanical approaches. In this work, the DFT (Density Functional Theory) program DMol3 in Materials Studio was used to study the interactions between the SO2 molecule and four systems. The adsorption energy, bond lengths, bond angle, charge transfer, and density of states of SO2 molecule on pristine graphene, N-doped graphene, Ga-doped graphene, and -Ga-N- co-doped graphene were investigated using DFT calculations. The obtained data indicate that the bonding between the SO2 molecule and pristine graphene is relatively weak, with a binding energy of −0.32 eV and a bond length of 3.06 Å, indicating physical adsorption. Next, the adsorption of the molecule on an N-doped graphene system was considered. The adsorption of SO2 molecules on N-doped graphene is negligible; generally, the interaction of SO2 molecules with this system does not significantly change the electronic properties. However, the adsorption energy of the gas molecule on Ga-doped graphene relative to pristine graphene increased significantly. The evidence of chemisorption is increased adsorption energy and decreased adsorption distance between SO2 and Ga-doped graphene. In addition, our results show that introducing -Ga-N- co-dopants of an “ortho” configuration into pristine graphene significantly affects the adsorption between the gas molecule and graphene. Thus, this approach is significantly practical in the adsorption of SO2 molecules.

The rapid and low-cost preparation of powder activated coke (PAC) is very important for the promotion of fluidized dry desulfurization technology of activated coke. In order to explore the effect of rapid pyrolysis process on SO2 adsorption capacity of PAC, the fractal analysis of PAC prepared under different atmospheres was carried out. The Frenkel–Halsey–Hill (FHH) method was used to determine two fractal dimensions D1 and D2, under relative pressures of 0–0.5 and 0.5–1, respectively. The results indicate that the fractal dimensions were influenced by the concentrations of activation agents with D1 ranging from 2.1838 to 2.8643 and D2 ranging from 2.7485 to 2.9257. The effect of steam on the fractal dimension of PAC sample is small, but oxygen has a great promotion effect on the fractal dimension. An n-shaped curve-based relationship between fractal dimensions and coke yields is observed with a peak values of fractal dimensions appearing around 64% yield. The SO2 adsorption capacity shows a consecutively positive linear correlation with D2, while it illustrates distinctly different linear rates with D1 in intervals of 2–2.6 and 2.6–3, respectively. Taking advantage of fractal analysis as research method, this paper clarified the influence of activation atmosphere and ablative degree on the SO2 adsorption capacity of PAC, and the research conclusion provided a basis for the PAC preparation with high SO2 capacity. [ABSTRACT FROM AUTHOR]

In this study, the corrosion mechanism in different regions of the welded joints in CO 2 /SO 2 saturated aqueous solution was investigated by electrochemistry and morphological analysis. The results demonstrated that SO 2 and its hydrolysis have some adsorption properties and tend to adsorb in the region of the base metal and generated FeS product. A dense corrosion product film could form on this region, effectively reducing the corrosion rate. Due to the selective adsorption which increases the potential difference between different regions of the welded joint, further intensifying the galvanic corrosion and ultimately leading to the failure of the welded joint. • SO2 reduces the corrosion rate in welded joints under saturated CO2 conditions. • The corrosion rate of base mental reduces but accelerates localized corrosion. • Corrosion rate of base mental decreases rapidly after the addition of SO2. • The galvanic corrosion of welded joints is accelerated by SO2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porous modified biochar was prepared by ZIF-8-assisted pyrolysis of bamboo. • The surface area enhanced from 49.6 to 557.4 m2/g after ZIF-8-assisted pyrolysis. • The SO 2 adsorption capacity of modified biochar can reach 166 mg/g at 30 °C. • Polar ZnO on the carbon surface promotes the conversion of SO 2 to SO 3 2−. Structural modification is a necessary means to improve the adsorption performance of biochar. A simple, efficient, and well-applicable modification method is often expected. In this study, zeolitic imidazolate framework (ZIF-8)-assisted pyrolysis of bamboo was employed to prepare modified biochar for improving its SO 2 adsorption performance. The physicochemical characteristics of biochars before and after modification were investigated and their SO 2 adsorption behaviors were examined using a fixed bed adsorption system. The results showed that the surface heteroatoms and pore structure parameters of biochar modified by ZIF-8-assisted pyrolysis were significantly improved, with nitrogen content and surface area increasing from 1.3 wt% and 49.6 m2/g to 4.2 wt% and 557.4 m2/g, respectively. Among all tested conditions, the modified biochar obtained through ZIF-8-assisted pyrolysis at 700 °C exhibited not only the highest SO 2 adsorption capacity (166 mg/g) but also a remarkable increase (up to 121 %) compared with pristine biochar under identical pyrolysis temperature conditions. Moreover, it exhibited good regeneration performance, with an adsorption efficiency of over 93 % after 8 cycles of SO 2 adsorption and desorption. Combined with characterization results regarding physical and chemical properties before and after SO 2 adsorption, it can be concluded that improved pore structure and the presence of polar ZnO on the surface are primarily responsible for promoting SO 2 adsorption onto modified biochar, resulting in the final existence as SO 3 2− rather that SO 4 2−. [ABSTRACT FROM AUTHOR]

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We systematically investigate the combined effect of both the defects, including single vacancy defects (SV) and Stone‐Wales defects (SW), and the decoration of Pt atom on the structural, electronic, and adsorption properties of graphene for SO2 molecule using the density functional theory (DFT). The calculations reveal that Pt atom can be stably combined on both SV defected graphene (SVG) and SW defected graphene (SWG) with the high‐binding energy of −7.03 and −2.61 eV, respectively. In addition, the SO2 molecule is chemically adsorbed on Pt‐decorated graphene with SV defects and SW defects, their adsorption energies are −1.402 and −1.891 eV, respectively. The adsorption of SO2 can significantly change the conductivity of the adsorbed system, which shows that Pt decorated SVG and SWG have good sensitivity to SO2. Moreover, compared with Pt decorated SVG, Pt decorated SWG has better adsorption ability for SO2 gas molecules, which corresponds to larger adsorption energy, strong orbital hybridization, and the obvious increase of conductivity. These results indicate that the combination of defects and Pt atom decoration can tune the electronic and adsorption properties of graphene, and provide insight into the application of graphene‐based gas sensors for SO2 gas molecules. [ABSTRACT FROM AUTHOR]

We systematically investigate the combined effect of both the defects, including single vacancy defects (SV) and Stone‐Wales defects (SW), and the decoration of Pt atom on the structural, electronic, and adsorption properties of graphene for SO2 molecule using the density functional theory (DFT). The calculations reveal that Pt atom can be stably combined on both SV defected graphene (SVG) and SW defected graphene (SWG) with the high‐binding energy of −7.03 and −2.61 eV, respectively. In addition, the SO2 molecule is chemically adsorbed on Pt‐decorated graphene with SV defects and SW defects, their adsorption energies are −1.402 and −1.891 eV, respectively. The adsorption of SO2 can significantly change the conductivity of the adsorbed system, which shows that Pt decorated SVG and SWG have good sensitivity to SO2. Moreover, compared with Pt decorated SVG, Pt decorated SWG has better adsorption ability for SO2 gas molecules, which corresponds to larger adsorption energy, strong orbital hybridization, and the obvious increase of conductivity. These results indicate that the combination of defects and Pt atom decoration can tune the electronic and adsorption properties of graphene, and provide insight into the application of graphene‐based gas sensors for SO2 gas molecules. [ABSTRACT FROM AUTHOR]

Capture, storage and subsequent controlled release or transformation of sulfur dioxide (SO2) in mild conditions is still a challenge in the material science field. Recent advances in the use of porous materials have demonstrated good SO2 capture, particularly in metal‐organic frameworks (MOFs), metal‐organic cages (MOCs), and porous organic cages (POCs). The striking feature of these porous materials is the high SO2 uptake capacity in reversible settings. A partially fluorinated MIL‐101(Cr) is stand‐alone material with the highest SO2 uptake in chemically stable MOFs. Likewise, metal‐free adsorbents like POCs exhibits a reversible SO2 uptake behavior. The SO2 adsorption characteristics of these three structurally and functionally unique adsorbent systems are highly dependent on the binding sites and mode of binding of SO2 molecules. This Review has highlighted the preferential binding sites in these materials to give a full perspective on the field. We anticipate that it will offer valuable information on the progress made towards improving SO2 capture by hybrid systems. [ABSTRACT FROM AUTHOR]

The sensing properties of the paddlewheel-type metal dimer (M-BTC: M = Fe, Ni, Cu, Zn, and Pd) toward SO2 gas were theoretically investigated using density functional theory (DFT) at the M06-L level of theory. Single-point calculations were carried at the M06 functional to correct the energetic properties and HOMO–LUMO energy gap. The O-bound adsorption complex of SO2 on the metal center of paddlewheels is found to be thermodynamically favorable than the S-bound ones. The trend of adsorption energy of SO2 on the metal center is in the order Pd-BTC < Cu-BTC < Ni-BTC < Zn-BTC < Fe-BTC. Among these five paddlewheels, the Ni-BTC and Zn-BTC paddlewheels are highly sensitive toward SO2 gas as compared to the other systems. The density of states reveals that the adsorption process significantly reduces the LUMO of the system to lower energies, enhancing the conductivity of the system. From DFT results, the energy gap of Ni-BTC and Zn-BTC is significantly reduced by 18.0 and 41.0% after the adsorption of SO2 on the metal center. These results suggest the great potential of Ni-, and Zn-BTC paddlewheels as SO2 sensors. [ABSTRACT FROM AUTHOR]

The removal of sulfur dioxide from industrial flue gas through dry flue gas desulfurization method commonly involves the use of adsorption process with porous sorbent. The efficiency of this process is highly dependent on the adsorption capacity and the adsorption rate of SO2 onto the sorbent materials. The use of KCC-1 mesoporous silica modified with calcium metal additives (Ca/KCC-1) in SO2 adsorption is examined in a fixed bed reactor system. The adsorption capacity of Ca/KCC-1 is found to be critically governed by the reaction temperature and inlet SO2 concentration where low values of both parameters are favorable to achieve the highest adsorption capacity of 3241.94 mg SO2/g sorbent. SO2 molecules are adsorbed on the surface of Ca/KCC-1 by both physisorption and chemisorption processes as assumed by the Avrami kinetic model. Thermodynamic study shows that the process is exothermic and spontaneous in nature, and changes from an ordered stage on the surface of KCC-1 towards an increasingly random stage. The process is well explained by Freundlich isotherm model indicating a slightly heterogeneous process and moderate adsorption capacity. The adsorption stage is limited by film diffusion at the initial stage and by intraparticle diffusion during the transfer of SO2 into the network of pores before adsorption takes place on the active sites. [ABSTRACT FROM AUTHOR]

Obtaining suitable adsorbents for selective separation of SO 2 from flue gas still remains an important issue. A stable Zr(IV)-MOF (Zr-PTBA) can be conveniently synthesized through the self-assembly of a tetracarboxylic acid ligand (H 4 L = 4,4',4'',4'''-(1,4-phenylenebis(azanetriyl))tetrabenzoic acid) and ZrCl 4 in the presence of trace water. It exhibits a three-dimensional porous structure. The BET surface area is 1112.72 m2/g and the average pore size distribution focus on 5.9, 8.0 and 9.3 Å. Interestingly, Zr-PTBA shows selective adsorption of SO 2. The maximum uptake reaches 223.21 cm3/g at ambient condition. While it exhibits lower adsorption uptake of CO 2 (30.50 cm3/g) and hardly adsorbs O 2 (2.57 cm3/g) and N 2 (1.31 cm3/g). Higher IAST selectivities of SO 2 /CO 2 (21.9), SO 2 /N 2 (912.7), SO 2 /O 2 (2269.9) and SO 2 /CH 4 (85.0) have been obtained, which reveal its' excellent gas separation performance. Breakthrough experiment further confirms its application for flue gas deep desulfurization both in dry and humid conditions. Furthermore, the gas adsorption results and mechanisms have also been studied by theoretical calculations. [Display omitted] • A stable Zr(IV)-MOF (Zr-PTBA) was synthesized conveniently. • Zr-PTBA shows efficient capture of SO 2 from SO 2 /CO 2 /N 2 /O 2 mixtures. • GCMC simulations and DFT calculations strongly support the experimental results. • Gas breakthrough experiments evaluate the efficient desulfurization of flue gas under dry and humid conditions. [ABSTRACT FROM AUTHOR]

The nature of adsorption between MOF absorbent and SO 2 remains a challenging issue due to the difficulty in understanding their interaction force and dynamic behavior on molecular level. Herein, a new series of M-MOF-74 (M = Co, Ni, Zn) with high SO 2 adsorption performance were synthesized through an improved solvothermal method. The interaction between M-MOF-74 (M = Co, Ni, Zn) and SO 2 was revealed by combining in-situ infrared spectroscopy and density functional theory (DFT) calculations. It was found that Zn-MOF-74 shows excellent SO 2 uptakes (8.16 mmol g−1), significantly higher than that of Co-MOF (6.11 mmol/g) and Ni-MOF (6.36 mmol/g). These results were consistent with SO 2 binding energies calculated at optimal adsorption sites, which were −11.1 kcal/mol, −12.2 kcal/mol, −18.2 kcal/mol for M-MOF-74 (M = Co, Ni, Zn), respectively. The specific adsorption behavior of Zn-MOF-74 towards SO 2 is attributed to its higher negative attraction of electrostatic potential(∼48.2 kcal/mol)and van der Waals pulling forces (∼−2.6 kcal/mol). The higher interaction force between Zn-MOF-74 and SO 2 was elucidated not only by their strong dominant dispersion interactions, but also by the formation of hydrogen bonding between SO 2 and benzene ring, as demonstrated by independent gradient model (IGM) and infrared analysis. What's more, a unique radial SO 2 movement with high speed of 323 p.m.2/ps, which was much higher than that of traditional molecular sieve (∼240 p.m.2/ps) adsorbent, were observed towards Zn-MOF-74 framework wall. Then the pore size of MOF-74 and SO 2 motion trajectory was analyzed by Molecular Dynamics. This work gives insight into mechanisms on SO 2 adsorption in MOFs. [Display omitted] • Synthesis of M-MOF-74 (M = Co, Ni, Zn) with high SO 2 adsorption performance via an improved solvothermal method. • Zn-MOF-74 shows excellent SO 2 uptakes significantly higher than that of Co-MOF and Ni-MOF. • The adsorption results were consistent with SO 2 binding energies calculated at optimal adsorption sites. • The high interaction force was elucidated by strong dominant dispersion interactions and hydrogen bonding formation. • A unique radial SO 2 movement with high speed which was much higher than that of molecular sieve were observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Facilely tuning the morphologies of polytertiary amine-functionalized SBA-15. • Superior dispersion and exposure of tertiary amine are given on worm-like SBA-15. • The N base sites in amine-zeolite interact with SO 2 for enhanced adsorption. • The worm-like composite shows highly selectivity for separating SO 2 from CO 2 , N 2. • The worm-like composite exhibits good SO 2 capture with stability and anti-water. The amine-based materials pose high potential for the adsorption of sulfur dioxide (SO 2). This work is aimed at modulating the morphologies of SBA-15 adsorbents by controlling the precursor self-assembly processes, for the sake of optimizing the utilization efficiency of amine species in the polytertiary amine (PTA)-functionalized SBA-15. It results that worm-like SBA-15 (WLS) material shows a better particle aspect ratio and well-defined pore structure, which helps to optimize the adsorption sites invoked by the preferable dispersion and exposure of PTA, thus amplifying the chemisorption of SO 2 on the adsorbent. Consequently, the functionalized WLS-PTA adsorbent exhibits remarkable SO 2 adsorption performance (15.43 mmol/g), exceptionally high selectivities of SO 2 /N 2 (27522) and SO 2 /CO 2 (6 5 2). Surprisingly, the desulfurization capacity can be further enhanced by the positive effect of the water vapor co-fed. It is unveiled that the whole SO 2 adsorption process mainly follows the dual site Langmuir-Freundlich isotherm model and Bangham model. This work sheds light on the design of polymer-solid composite adsorbents for selective capture of SO 2. [ABSTRACT FROM AUTHOR]

A complex air pollution environment requires filters to be multifunctional. Nanofibrous materials with surface-loaded metal–organic frameworks (MOF-fibers) are reasonable structures for multifunctional air filtration. These materials can not only utilize the network structure of fibers to intercept particulate matter (PM) but also retain the porous structure of the MOFs to adsorb toxic gas. Epitaxial growth methods are commonly utilized to prepare MOF-fibers but are uneconomical and time-consuming. Herein, a facile self-assembly strategy is developed to prepare zeolitic imidazolate framework-polyimide (ZIF-PI) nanofibers with an interconnected network structure and high porosity for air filtration applications. Due to their unique structure, the ZIF-PI nanofibrous membrane exhibited high PM2.5 filtration efficiency and enhanced SO2 adsorption capacity. Moreover, by exploring the morphology evolution of the ZIF-PI nanofibrous membrane, a possible "synergistic effect of hydrophobic and electrostatic force" self-assembly mechanism was demonstrated. [ABSTRACT FROM AUTHOR]

To study the effect of different modification reagents on activated carbon (AC), HNO3, H2SO4, H2O2, H2C2O4, and H3PO4 were chosen to modify AC. Then a series of Mn/AC catalysts were prepared by impregnation method. The denitrification performance and SO2 adsorption activities of these catalysts were tested. The results indicated that the catalyst prepared by HNO3-modified AC has both the highest NO conversion and SO2 adsorption activity. The NO conversion can reach 80% at 180 °C and SO2 saturated adsorption time can reach 30 min. To investigate the enhanced modification mechanisms of HNO3, the various modified samples were characterized by SEM-EDS, XPS, FTIR, and NH3-TPD. And the results show HNO3 can effectively increase the amount of chemical adsorbed oxygen on the surface of AC. And on the other hand, the nitrogen-containing functional groups introduced by HNO3 can promote the adsorption of NO, thus improving the denitrification performance. As a result, HNO3 can play a better role in activating AC, and the catalyst modified by HNO3 is more conducive to be used as the carrier of SCR catalysts. [ABSTRACT FROM AUTHOR]

The amino group in the MOF NH2‐MIL‐101(Cr) was post‐synthetically converted into urea‐groups partially using either ethyl isocyanatoacetate, furfuryl isocyanate, p‐toluenesulfonyl isocyanate or 3‐(triethoxysilyl)propyl isocyanate in acetonitrile. The derived four novel urea‐MOFs exhibit the expected lower BET surface areas and pore volumes than MIL‐101(Cr) and NH2‐MIL‐101(Cr) MOFs but the partially p‐toluenesulfonyl‐urea‐modified MOF exhibits an outstanding SO2 adsorption capacity of 823 cm3 g−1 (corresponding to 36.7 mmol g−1 or 70 wt.% at T=0 °C and 0.9 bar), which is the second highest SO2 uptake of any known material today – surprisingly even better than for highly porous MIL‐101(Cr) with an uptake of 645 cm3 g−1 SO2 under the same conditions. The high uptake is linked to the favorable dipole interactions of SO2 with the sulfonyl group of the p‐toluenesulfonyl‐modified MOF. [ABSTRACT FROM AUTHOR]

[Display omitted] • MnO x -SiO 2 catalyst with good sulfur resistance and N 2 selectivity was prepared. • Doping of SiO 2 inhibited the adsorption of SO 2 and improved the sulfur resistance. • Doping of SiO 2 reduced the excessive oxidation of NH 3 and improved the N 2 selectivity. Manganese-based catalysts have excellent catalytic performance for the effective removal of NO x in low-temperature flue gas through selective catalytic reduction with NH 3 (NH 3 -SCR). However, the catalysts suffer from poor SO 2 resistance and N 2 selectivity in the actual process, which still need to be solved. In this study, MnO x -SiO 2 mixed oxide catalysts were designed and prepared by coprecipitation method to improve the SO 2 resistance and N 2 selectivity in NH 3 -SCR process. In the presence of 100 ppm SO 2 , MnO x -SiO 2 (0.72) catalyst showed excellent sulfur resistance with the conversion of NO x reached 95 % even after introducing SO 2 for 8 h. The doping of SiO 2 greatly improved the specific surface area and surface acidity of the catalyst, which was conducive to the adsorption of NH 3. Meanwhile, the redox performance of the catalyst was decreased, improving the N 2 selectivity. The study on the sulfur resistance mechanism revealed that the doping of SiO 2 reduced the adsorption of SO 2 on the surface of catalyst, protecting the active components and avoiding the accumulation of sulfates, thus achieving good sulfur resistance performance. This work provided an environmentally friendly NH 3 -SCR catalyst by inhibiting SO 2 adsorption to have good catalytic performance and SO 2 resistance. [ABSTRACT FROM AUTHOR]

Due to the impact of toxic gases on human health, considerable interest has been shown in detecting noxious air pollutants, particularly sulfur dioxide (SO2), both experimentally and theoretically. This work provides new insights into the adsorbing (SO2) molecules on the surface of metal-oxide graphitic structures, i.e., Beryllium-Oxide (BeO), Zinc-Oxide (ZnO), and Ni-decorated graphene applying a first-principles study. Computational analyses suggest that the type of binding of SO2 molecule on BeO and ZnO sheets is physisorption so that binding energies of −0.405 and −0.154 eV were assigned to ZnO and BeO nanosheets in that order. The adsorption energy of SO2 on metal oxide sheets was much higher than the pristine graphene. Taking pristine graphene as an adsorbent for SO2 molecule, it was found that such nanomaterial is not an efficient adsorbent due to the weak interactions (−0.157 eV) and low electron charge transfer (0.042 e) present in SO2/graphene complex. To overcome this issue, graphene nanosheets decorated with nickel atoms were studied for interaction with SO2 molecules; the results indicate that the SO2 molecules were chemisorbed on Ni-decorated graphene sheets with an adsorption energy of −2.297 eV. Chemisorption of SO2 molecules on Ni-decorated graphene sheets was proven by the strong orbital hybridization between Ni 3d and sulfur 3p orbitals in the Projected Density of States (PDOS) plot. This work provides useful information about SO2 adsorption on Ni-decorated graphene sheets in order to develop a new class of gas sensing devices. Superior chemisorption of SO2 on Ni-decorated graphene sheets compared to the physical adsorption on BeO and ZnO sheets makes Ni-decorated graphene a potential candidate for detecting SO2 molecules. [ABSTRACT FROM AUTHOR]

Growing concerns over poor air quality, especially in urban and industrial regions, have led to increased global demands for advanced air-purification technologies. However, the stability and airborne pollutant control abilities of the available air-purification materials under diverse environmental conditions are limited. Thus, the advanced development of filtration materials that can effectively control different types of pollutants, such as particulate matter (PM) and gaseous pollutants, simultaneously has attracted attention. The zeolitic imidazolate framework (ZIF), a type of porous metal-organic framework (MOF), is a promising material for capturing weakly acidic toxic gases such as SO 2 owing to its excellent adsorption performance and high thermal and chemical stability. In this study, we successfully developed an ultrastable necklace-like multifunctional hybrid membrane via the cetyltrimethylammonium bromide-assisted in situ growth of zeolitic imidazolate framework (ZIF)-67 crystals on electrospun Co 2+ -doped poly(vinylidene fluoride) nanofibers (70 nm) that can be used in different moisture environments to achieve sustainable air-filtration performance. The hybrid nanocomposite membrane demonstrated excellent performance for the simultaneous control of intractable fine PM 0.3 (filtration efficiency, 99.461%) and SO 2 (adsorption capacity, 1476.5 mg g -1 ) under different humidity conditions. This study contributes to the optimal synergistic integration of the advanced metal-organic framework (MOF)-nanofiber nanocomposite membranes and can guide the rational design and conceptualization of a facile and novel membrane for various applications in the environmental science and energy fields.

[Display omitted] • One-step CO 2 -NH 3 modification promoted the SO 2 adsorption of biochar. • The SO 2 adsorption capacity of BCAN-800 can reach 201.89 mg/g at 30 °C. • Hydrogen bond plays an important role in SO 2 adsorption on N-doped biochars. • At medium–high temperatures, amino groups combined with SO 2 to form sulfamide. • SO 2 mainly existed in a form of SO 4 2−/R-O-SO 2 -OR′ as temperature exceeds 120 °C. Nitrogen-doped biochar is considered as a renewable, cost-effective, and promising SO 2 adsorbent. However, it is difficult to improve the physicochemical properties of biochar synergistically and clarify the adsorption mechanism. Therefore, in this study, a one-step high-temperature CO 2 -NH 3 modification method was proposed for biochar to improve its SO 2 adsorption, and the in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (in situ DRIFTS) was used to reveal the interface reaction mechanism between SO 2 and nitrogen-doped biochar. The results showed that when the modification temperature exceeded 700 °C, CO 2 and NH 3 exhibited significant thermal activation and nitrogen doping on biochar simultaneously. Under a modification temperature of 800 °C (BCAN-800), the microporous surface area and nitrogen content of modified biochar reached the highest value of 563.83 m2/g and 6.63 wt%. The SO 2 adsorption capacities of BCAN-800 were up to 201.89 mg/g and 145.68 mg/g at 30 °C and 120 °C, respectively. The results of in situ DRIFTS showed that dimeric and bridge hydrogen bonds were the main SO 2 adsorption sites on nitrogen-doped biochar at 30 °C. With the increase of adsorption temperature, nitrogen-containing groups as the main adsorption site could combine with SO 2 to form sulfamide (60 °C), which eventually existed in a more stable form of SO 4 2−/R-O-SO 2 -OR′ (120 °C). [ABSTRACT FROM AUTHOR]

One of the major challenges in environmental and atmospheric science is understanding the effects of mineral dust's surface physiochemical properties and pre-adsorbed volatile organic compounds on the conversion of atmospheric pollutants. However, the process of adsorption and conversion of polluting gases on typical mineral dust surface is not fully understood. In this study, we systematically investigated the impact of surficial hydroxyl groups on the α-quartz {001} surface, oxidizers, and adsorbed phenanthrene (Phe) on the adsorption and oxidation process of SO 2 by using density functional theory. Our findings indicate that the presence of hydroxyl groups on the α-quartz {001} surface increases SO 2 adsorption whereas the presence of Phe decreases the SO 2 capture capabilities. On pristine α-quartz {001} surfaces, SO 2 tends to form dissociative SO 4 2- groups and adsorb SO 3. While surficial hydroxylation of α-quartz {001} facilitates the desorption of SO 3 , resulting in fewer dissociative SO 4 2- groups and HSO 3 - salt. These results are consistent with our heterogeneous reaction of SO 2 and α-quartz. In addition, O 3 is more effective than O 2 in the oxidation of SO 2. Meanwhile, Phe inhibits the adsorption of HSO 3 - salt on hydroxylated α-quartz {001} surfaces. This study not only highlights the process surficial hydroxyl groups and adsorbed Phe regulate the evolution of adsorbed SO 2 on α-quartz {001}, but also revealed the formation mechanism of the sulfur-containing aerosols. [Display omitted] [ABSTRACT FROM AUTHOR]

• Preparation of activated carbons by chemical activation with CuCl 2. • In-situ impregnation of copper in one single step during activated carbon synthesis. • H 2 S and SO 2 breakthrough tests show the efficiency of the in-situ impregnation method. • Possible retention mechanisms of H 2 S and SO 2 on the prepared carbons are proposed. H 2 S and SO 2 are toxic compounds that are part of the main air pollutants. They can also induce corrosion and are responsible for acidic rain. Among the methods for their capture, adsorption on copper impregnated activated carbons is one of the most efficient. The latter are generally obtained in a two-step process, consisting of the preparation of the activated carbon and then its impregnation with copper. The aim of this work is to elaborate an efficient adsorbent of H 2 S and SO 2 in one single step. This goal is reached by an in-situ impregnation of copper using an original technique based on chemical activation using CuCl 2 as activating agent which, as far as we know, was not used before in this role, i.e. as the main activating agent. The carbonisation was carried out to 800 °C either in N 2 or CO 2. The obtained materials have a BET surface area of around 400 m2/g and a copper content by weight of about 20%. They were tested successfully against SO 2 and H 2 S by breakthrough measurements. In fact, they showed better results than an activated carbon prepared by chemical activation with ZnCl 2 (S BET 1600 m2/g). Thermogravimetric analysis before and after breakthrough tests allowed the proposition of possible mechanisms for the retention of H 2 S and SO 2 on the prepared materials. This new one step preparation method using CuCl 2 would permit a gain of time and energy for obtaining efficient activated carbons intended to capture SO 2 and H 2 S. [ABSTRACT FROM AUTHOR]

Coal-based activated carbons (ACs) were prepared from Shenhua lignite by chemical activation of ZnCl2. The surface functional groups of ACs were modified by NaOH to study the adsorption of SO2 in flue gas. Scanning electron microscope (SEM) was used to observe the surface morphologies, N2 adsorption was used to characterize the pore structures, Fourier transform infrared spectroscopy (FTIR) and Boehm titration were used to investigate the functional groups. The preparation parameters of ACs were discussed based on the response surface methodology (RSM) method, and a prediction model for the surface area was established based on carbonization temperature, carbonization time and heating rate. The optimum conditions for preparation of ACs by RSM were as follows:carbonization temperature of 700 °C, heating rate of 15 °C/min, and carbonization time of 3 h. The BET surface area and microporous surface area of the obtained AC were 599 m2/g and 269 m2/g, respectively. The effects of NaOH concentration on the pore structures, surface functional groups and SO2 adsorption capacities of ACs were investigated. Results showed that the pore structures were severely damaged after NaOH modification, and the pores were mainly distributed in the range of 0.5-0.6 nm, 0.7-0.9 nm and 1. 0-4. 0 nm. Highest BET surface area (681 m2/g) and microporous surface area (292 m2/g) was reached with treatment by 20% NaOH. This illustrated that low concentration of alkali treatment could expand pores in ACs, while high concentration of alkali might destroy the pore structures, leading to the decrease in surface area and pore volume. The amount of acidic groups decreased with the increasing of alkali concentration, while the basic functional groups increased. AC treated with 30% NaOH exhibited the highest content of basic groups (0. 557 mmol/g). The correlations between the microporous surface area and the content of basic groups with the SO2 adsorption amount were further analyzed. The adsorption capacities of SO2 were positively linearly correlated with the amount of basic groups and microporous surface areas, and the correlation coefficient of basic groups was higher than the microporous surface area. Therefore, the surface basic functional groups and microporous structure were beneficial to the adsorption of SO2 on activated carbon. [ABSTRACT FROM AUTHOR]

Sulphur dioxide (SO2) is an important atmospheric pollutant, and capture of SO2 is of great importance for the environment, human health and market. Carbon based materials, especially activated carbon, are mostly used for adsorption purposes. However, there is a notable lack on adsorption of SO2 on graphene oxide (GO) fibers and fiber web surface. In this study, the effect of addition of activated carbon, pH of GO dispersions, hydrazine reduction and oxygen/argon plasma treatment on SO2 adsorption of GO fiber web surface were evaluated. It was seen that GO fiber web surface with activated carbon provides high SO2 adsorption (896 mg SO2/g) which is very higher than many of carbon based materials presented in the literatures. Single coagulation bath increases surface roughness of fiber and provides higher functional group than three coagulation baths leading to higher SO2 adsorption capacity. [ABSTRACT FROM AUTHOR]

Highlights • A new insight into SO 2 physisorption on N-doped carbon surface is revealed. • Quaternary N doping enhances SO 2 physisorption on the basal plane of carbon surface. • Pyridinic and pyrrolic N doping can enhance SO 2 physisorption at the carbon edge. • Noncovalent interactions and EDA analyses are conducted to reveal the interaction types. Abstract Nitrogen-containing functional groups in carbon surface have been demonstrated favorable for SO 2 adsorption. While previous literature suggested the SO 2 chemisorption nature due to N doping, this work highlights the enhanced physical adsorption interactions between SO 2 and nitrogen-containing groups, which are elucidated by density functional theory calculations with the analyses of electrostatic potential, noncovalent interactions, and energy decomposition. The results indicate that for pristine carbon surface, SO 2 physisorption mainly occurs on the basal plane due to van der Waals interactions. N doping changes the electron distribution of carbon surfaces, thus altering not only intensity but also types of involved interactions. The quaternary N atoms promote SO 2 physisorption mainly by enhancing the van der Waals interactions between the basal plane and SO 2 while the improvement of SO 2 physisorption by pyridinic and pyrrolic N species should be ascribed to the enhanced electrostatic interactions at edge sites. These results demonstrate that N doping could boost the effective surface for SO 2 adsorption by facilitating both van der Waals and electrostatic interactions. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Adsorbent CuO/g-Al2O3 for adsorption of SO2 were prepared by impregnating Cu(NO3)2.3H2O solution. Five types of adsorbent were obtained 5Cu (intended Cu concentration of 5%, actual of 4.92%), 8Cu (7.68%), 15Cu(14.13%), 22Cu (20.80%) and 27Cu (25.80%). For activity test, model gas containing SO2 with a concentration of about 0.755 mol/m3 were passed through the bed of 1 gram adsorbent at a flow rate in the range of 1.4-1.8 mL/s. Adsorption of SO2 were carried out at a constant temperature of 300, 350, 400 or 450 °C. Increasing sulfur loadings (gram of sulfur per gram of adsorbent) were observed with increasing adsorption temperatures, but not with increasing Cu content in the adsorbent. Among those types, adsorbent of 8Cu was considered as the best with respect to the sulfur loading (3 g of sulfur per 100 g of adsorbent). Adsorbent 5Cu had actually a better sulfur loading, but it was suspected being contributed also by adsorption of SO2 on Al2O3. The shrinking core model was used in the kinetic study of adsorption using 8Cu and with additional assumption of a spherical particle. Compared to film diffusion and pore diffusion controlling step models, the reaction rate limitation was the best to fit the experimental data. The reaction rate constant for this model at temperatures of 300, 350, 400 and 450 °C were 0.022, 0.038, 0.042, and 0.059 kg.m.mol-1.min-1, respectively. The activation energy was 21.25 kJ.mol-1 and the frequency factor was 2.02 min-1.

ZnO/AC composites，Fe2O3 / AC composites，ZnFe2O4/AC and AC blank materials，composites were prepared by In-situ hydro-thermal method using the activated carbons as supporter. The structure and properties of the obtained composite were characterized by scanning electron microscope (SEM)，X-ray spectrometer (EDS)，X-ray diffraction(XRD)，Fourier transform infrared spectroscopy (FT-IR)，physical adsorption instrument(BET) and X-ray photo-electron spectroscopy (XPS) analysis. In addition，the adsorptive property of AC was tested at 30 °C in simulated flue gas. The results showed that the metal oxide compound，as an active component 9 was successfully loaded on activated carbons. After introducing the metal oxide compound，the specific surface area pore volume decreased，while the pore diameter increased，and the SO2 adsorption can be improved significantly. It was confirmed that desulphurization efficiency by activated carbon loaded with ZnFe2O4 which processed a high specific surface area of 435.9 m²/g，entrance of 0.37 cm³/g，the desulfurization performance test sample breakdown in the time of 136.0 min，and the sulfur capacity of 168.3 mg/g，in comparison to the AC、ZnFe2O4 and other composite materials. [ABSTRACT FROM AUTHOR]

ZnSe nanotubes were constructed and optimized in order to analyze the adsorption behaviour of environmentally hazardous gases such as SO2 and CO2 by using density functional analysis. Different sites on the nanotubes, such as Zn and Se, were studied for adsorption energy, Mullikan population and the recovery time of the ZnSe nanotube during the adsorption process. The obtained results show that compared to SO2 molecules, the ZnSe nanotubes are more reactive to CO2 molecules. To study the electronic transport properties of the ZnSe nanotubes with and without gas molecules, a two-probe system was constructed and the transport properties were studied by implementing a non-equilibrium Green’s function. The transport properties were analyzed in terms of the device density of states, transmission curves and the V–I characteristics. The results confirm that the ZnSe nanotubes are more favourable for CO2 molecules compared to the SO2 molecules. [ABSTRACT FROM AUTHOR]

Activated carbons modified with ammonia were used as sorbents of SO2. The SO2 uptake was dependent on both texture and type of surface groups introduced onto the studied materials. The most important parameter was the size of micropores, which positively influenced the amount adsorbed. Differing chemical properties had a mixed influence. The oxygen-containing groups negatively affected SO2 amount adsorbed. N-containing moieties had a positive influence, while the amount of introduced nitrogen was not the major parameter where SO2 uptake was concerned, possibly due to the differences in the type of introduced surface species. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fibrous and porous carbon microspheres was used to load deep eutectic solvent. • NCMs-DESs can be used as a novel adsorbent for highly-efficient SO 2 capture. • NCMs-DESs showed excellent properties of selectivity and reuse for SO 2 adsorption. Deep eutectic solvents (DESs) are promising absorbents for SO 2 capture. However, the high viscosity of DESs limits their applications in the SO 2 separation industry. In this study, nanofibrous and porous carbon microspheres (NCMs) with a large surface area (344.5 m2·g−1) were prepared from chitin and used to load [emim]Cl + imidazole DESs for the first time using a physical dispersion process. The DESs were uniformly adsorbed onto the nanofibrous carbon surfaces, and a novel adsorbent (NCMs- x DESs) was formed with a three-dimensional hierarchical porous structure. NCMs showed high loading capacity for DESs (the ideal load ratio was 5:1) and exhibited an appropriate solid-state with significantly decreased DESs viscosity. NCMs- x DESs were used to capture SO 2 , and the results showed that NCMs-5DESs had the highest adsorption capability for SO 2 compared with other NCMs- x DESs. The adsorption capacity of NCMs-5DESs for pure SO 2 reached up to 14.66 mol/kg under 25 ℃ and 1 bar conditions. The adsorption capacity remained at 2.89 mol/kg even at low-content SO 2 (1,700 ppm) in the mixed gas, which was higher than most solid adsorbents reported in the literature. The excellent adsorption capability was due to the porous structure of the NCMs and the multiple interactions between DESs and SO 2. The DESs contained the strong electron-donating ability of Cl−1 and weakly basic tertiary N that can interact with SO 2 via electron deficiency and Lewis acids. H-bonding interactions also formed between the DESs and SO 2. Additionally, the NCMs-DESs absorbent exhibited excellent reversibility and selectivity for SO 2 adsorption after ten cycles. Therefore, the NCMs-DESs absorbent may be a promising candidate for SO 2 capture in polluted gas. [ABSTRACT FROM AUTHOR]

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To meet the requirements of efficient adsorption of the atmospheric pollutant SO 2 and low energy consumption regeneration of adsorbents, metal oxide-modified biomass carbon materials were prepared by microwave heating, and the effects of microwave power, iron oxide loading, and calcination time on the activated carbon load with iron oxides (ACIO) were investigated. The desulfurization mechanism of ACIO was characterized by multiple methods, and the process was simulated using density functional theory (DFT). The results indicated that the optimum preparation conditions were as follows: the loading amount of iron oxides was 10 wt%, the microwave power was 500 W, and the calcination time was 10 min. The adsorption capacity of ACIO corresponding to the optimum preparation conditions was 146.31 mg/g, and the thermal conductivity was 0.58 W/(m·K), which led to a reduction in the regeneration energy consumption by approximately 2800 J/g. Furthermore, ACIO exhibited good SO 2 cyclic adsorption-desorption performance, and the SO 2 adsorption capacity after five cycles of adsorption and desorption was maintained at 46.98 mg/g. The DFT calculation results indicate that chemical adsorption between SO 3 and Fe 2 O 3 under anhydrous conditions occurred during the desulfurization process and contributed to the sulfate formation reaction. [Display omitted] • Proposed an iron oxide modified biochar desulfurizer. • SO 2 adsorption capacity of the desulfurizer can reach 146.31 mg/g. • Chemisorption between Fe 2 O 3 and SO 3 exists under anhydrous conditions. • H 2 O alters the pathway of sulfate production. [ABSTRACT FROM AUTHOR]

The use of carbonaceous adsorbent to remove SO 2 from flue gas is regarded as the most environmentally friendly flue gas desulfurization technology presently known because of the extensive pores and rich functional groups characterizing the adsorbents. The main purpose of this work is to clarify the effects of the thermal regeneration temperature and cycle times on SO 2 adsorption performance by analyzing the physicochemical properties of carbon adsorbent and to reveal the synergistic relationship between adsorbent mass loss and gas release. Commercial powdered activated coke (PAC) prepared from coal was used. Experimental results show that the influence of the regeneration temperature on the physicochemical properties of the adsorbent leads to different variation trends in the circulating desulfurization performance. The regeneration rates of the regenerated PACs after 10 cycles at 250/450/650/850 °C were 37.71%, 72%, 118.66%, and 148.06%, respectively. Pore blockage and oxygen accumulation on the carbon surface are the reasons for the decline in the desulfurization performance of regenerated PAC at 250–450 °C. Pore development, primarily in the form of micropores, and the inhibition of surface oxidation cause the optimization of the desulfurization performance of regenerated PAC at 650–850 °C. The release of carbon atoms in CO 2 /CO gas during regeneration causes loss of PAC mass; meanwhile, oxygen atoms mainly originate from the adsorption process. This study systematically clarifies the relationship between the physicochemical properties of PAC and the evolution of SO 2 cyclic adsorption properties, which provides guidance for the design of regeneration parameters for desulfurization systems. • The increase of regeneration temperature promotes the sulfur capacity of PAC. • The release of CO 2 /CO gas during regeneration leads to PAC mass loss. • Temperature has a cumulative effect on the sulfur capacity during the cycle. • Micropores and defective active sites increase under high temperature regeneration. [ABSTRACT FROM AUTHOR]

Power plants emit sulfur dioxide (SO 2) during combustion, which is typically removed via wet flue gas desulfurization, but this process produces numerous secondary pollutants. Ionic liquids (ILs) can potentially be used to remove SO 2 , but they suffer from poor mass transfer rates. Hydroxyl ammonium ILs are classical cheap ILs that contain electron-rich O and N sites that favor high absorption capacities. To accelerate mass transfer, two hydroxyl ammonium ILs, triethanolamine citrate and triethanolamine lactate, were immobilized on activated carbon (SILs) and used to capture SO 2 from simulated flue gas. They exhibited excellent adsorption at low SO 2 partial pressures due to the presence of a large gas-liquid interface. The molar adsorption ratios reached 7.65 and 2.40 mol/mol at 10 kPa SO 2. The SILs possessed good SO 2 selectivity in SO 2 /CO 2 and SO 2 /O 2 mixtures, because of the only 8% reduction in the total adsorption of SILs at 60 °C. And they exhibited excellent reversibility in which their total adsorption capacities were unaffected after 5 adsorption-desorption cycles. The mechanism analysis revealed that chemical adsorption was the major adsorption route, although physical adsorption also occurred. The main reactive sites included C–O and N–H groups in the ionic liquid. These SILs may potentially replace traditional chemical absorption materials for the separation of SO 2 from flue gas. • SILs exhibits excellent adsorption in low SO 2 partial pressure. • Molar adsorption ratios of 7.65 and 2.40 mol/mol on TC-AC and TL-AC. • The total adsorption value in solution decreased by 5.3% after 4 cycles. • Good selectivity for SO 2 from SO 2 /CO 2 or SO 2 /O 2. • Combination of physical and chemical adsorption. [ABSTRACT FROM AUTHOR]

Adsorbent CuO/γ-Al2O3 for adsorption of SO2 were prepared by impregnating Cu(NO3)2.3H2O solution. Five types of adsorbent were obtained 5Cu (intended Cu concentration of 5%, actual of 4.92%, 8Cu (7.68%), 15Cu(14.13%), 22Cu (20.80%) and 27Cu (25.80%). For activity test, model gas containing SO2 with a concentration of about 0.757 mol.m-3 were passed through the bed of 1 gram adsorbent at a flow rate in the range of 1.4-1.8 mL.s-1. Adsorption of SO2 were carried out at a constant temperature of 300, 350, 400 or 450 °C. Increasing sulfur loadings (gram of sulfur per gram of adsorbent) were observed with increasing adsorption temperatures, but not with increasing Cu content in the adsorbent. Among those types, adsorbent of 8Cu was considered as the best with respect to the sulfur loading (3.71 g of sulfur per 100 g of adsorbent). Adsorbent 5Cu had actually a better sulfur loading, but it was suspected being contributed also by adsorption of SO2 on γ-Al2O3. The shrinking core model was used in the kinetic study of adsorption using 8Cu and with additional assumption of a spherical particle. Compared to film diffusion and pore diffusion controlling step models, the reaction rate limitation was the best to fit the experimental data. The reaction rate constant for this model at temperatures of 300, 350, 400 and 450 °C were 0.015, 0.027, 0.030 and 0.042 kg⋅m⋅mol-1.min-1, respectively. The activation energy was 21.37 kJ.mol-1 and the frequency factor was 1.45 min-1. [ABSTRACT FROM AUTHOR]

Influence of the surficial physiochemical properties on the adsorption and conversion of SO 2 on calcite {1 0 4}. [Display omitted] • The adsorption of SO 2 can be enhanced by both the surface defects and the adsorbed H 2 O on the calcite {1 0 4}. • Oxidation of SO 2 with O 3 is proposed to occur by an Eley-Rideal mechanism. • For Mn-doped calcite {1 0 4}, SO 2 can be converted to adsorbed SO 3 by O 3. The presence of H 2 O is adverse to the conversion of SO 2. • For CO 3 2– vacancy defected calcite {1 0 4}, with the aid of dissociated H 2 O, SO 2 can be easily converted into sulfate. The role of mineral dust on atmospheric pollutions formation is one of the significant challenges in environmental and atmospheric science. The conversion of atmospheric pollutions on mineral dust depends largely on its surface physiochemical properties. However, the adsorption and conversion of polluting gases on typical mineral dust surface in China are still poorly understood. In this study, the impact of calcite surface defects, oxidizers and adsorbed H 2 O on the adsorption and oxidation process of SO 2 on calcite {1 0 4} surface is systematically studied by density functional theory (DFT) method. The results indicate that the surface defects enhance the adsorption of SO 2 on calcite {1 0 4} surface. Compared with O 2 , O 3 is more beneficial for the oxidation conversion of SO 2 on various calcite {1 0 4} surfaces. For pristine calcite {1 0 4} and Mn-doped calcite {1 0 4}, SO 2 can be converted to adsorbed SO 3 by O 3 , while adsorbed H 2 O inhibits this process. For CO 3 2– vacancy defected calcite {1 0 4} surface, with the aid of dissociated H 2 O, SO 2 can be easily converted to sulfate instead of adsorbed gaseous SO 3. Thus, the evolution of the adsorbed SO 2 on calcite {1 0 4} can be regulated by the surface physiochemical properties and the adsorbed H 2 O. [ABSTRACT FROM AUTHOR]

Material science, metal-organic cages, metal-organic frameworks, porous organic cages, SO2 adsorption Cover Feature: Sulfur Dioxide Capture in Metal-Organic Frameworks, Metal-Organic Cages, and Porous Organic Cages (ChemPlusChem 6/2022) Keywords: material science; metal-organic cages; metal-organic frameworks; porous organic cages; SO2 adsorption EN material science metal-organic cages metal-organic frameworks porous organic cages SO2 adsorption 1 1 1 07/04/22 20220601 NES 220601 B The cover feature image illustrates b sulphur dioxide adsorption on three types of porous material: metal organic frameworks (MOFs), metal organic cages (MOCs), and porous organic cages (POCs), represented by sky lanterns. [Extracted from the article]

[Display omitted] • Hierarchical porous nanowire aerogel catalysts with excellent NH 3 -SCR performance. • SO 2 promotes the adsorption activation of NH 3 on the MnCe-N catalyst. • The nanowire structure increases the specific surface area and the surface acidity. • Nanowire structure effectively inhibits SO 2 adsorption and sulfate generation. The presence of SO 2 in industrial flue gases will cause permanent deactivation of the catalyst active centre. Therefore, an effective method to improve the SO 2 resistance of manganese-based catalysts at low temperatures is urgently needed. In this work, a hierarchical porous nanowire structure catalyst was designed by the in situ self-assembly method to inhibit SO 2 adsorption. This hierarchical porous nanowire aerogel catalyst with great BET surface area and surface acidity exhibited NOx conversion above 90% at 100–400 °C. Notably, the NOx conversion of the MnCe-N catalyst was almost not inhibited by SO 2 (250 ppm) compared to the 33% decrease of the MnCe-P catalyst. On the MnCe-P catalyst, SO 2 has strong competitive adsorption with NH 3 and NO, and the stronger adsorption capacity of SO 2 inhibits the adsorption activation of the reaction gas and hinders the reaction proceeding through the L-H mechanism. Meanwhile, a large quantity of sulfate is formed on the catalyst surface, which prevents the active centre to participate in the redox reaction. The structure of nanowires enhances the number of acid sites, facilitates the adsorption and activation of NH 3 , and effectively inhibits the adsorption of SO 2 on the MnCe-N catalyst. Fewer sulfate species are generated and difficult to deposit and aggregate on the catalyst surface, as a result, the active centre is less affected by sulfate species. The stable adsorption of NH 3 -related species ensures reliable reaction on MnCe-N through the E-R mechanism. This work emphasizes the importance of hierarchically porous structures in improving the NH 3 -SCR performance and SO 2 resistance of monolithic catalysts, and provides new insights into the design of highly efficient and stable catalytic materials. [ABSTRACT FROM AUTHOR]

Highlights: [•] Tailoring a porous structure in activated carbon fibers enhances SO2 adsorption. [•] Cobalt naphthenate enhances spinnability and catalyzed the specific porous structure. [•] Combination of micropores and large mesopores yields the highest SO2 adsorption rates. [Copyright &y& Elsevier]