Sodium borohydride has significant potential for chemical hydrogen storage, and developing efficient catalysts to improve its hydrolytic hydrogen production is crucial for advancing practical applications. In this work, a cobalt-nickel bimetallic metal-organic framework (MOF) catalyst was synthesized using a simple, one-step solvothermal method. A high-performance bimetallic MOF catalyst (Co3Ni2-MOF) for sodium borohydride hydrolysis was created by adjusting the Co-to-Ni metal ratio. Multiple characterization techniques confirmed that the combined charge-transfer synergy and geometric effects between Co and Ni ions enhance both catalytic activity and structural stability. Performance tests showed that the hydrogen generation rate of Co3Ni2-MOF was significantly higher than that of monometallic MOFs, being 1.6 and 5.2 times higher than those of Co-MOF and Ni-MOF, respectively. Under optimized conditions, the rate increased further to 3147.7 mL center dot min- 1 center dot g- 1, surpassing similar catalysts reported in the literature. Additionally, the catalyst displayed exceptional cyclic stability, maintaining 88.9 % of its catalytic efficiency after five cycles, and exhibited a low activation energy of 36.9 kJ center dot mol- 1, which was 15-24 % lower than that of other published Co-based catalysts. This study offers new insights into designing efficient bimetallic MOF catalysts, particularly by addressing challenges in one-step synthesis and non-noble-metal synergy for sodium borohydride hydrolysis. It provides a strong foundation for future industrial applications.

Discrepancies among established measurement methods currently hinder reliable comparisons of adsorbent performance across different studies. In this research, we systematically examined the CO2 adsorption behavior of five adsorbents (NbOFFIVE-1-Ni, 13X zeolite, ZTC, ZTC-K+, and MOF-199) using three standard test methods: thermogravimetric analysis (TGA), a fixed-bed reactor coupled with mass spectrometry (FB/MS), and a static volumetric approach under both pure CO2 (100%) and ultra-dilute CO2 (400 ppm) conditions. For pure CO2, the TGA and static volumetric methods yielded accurate and consistent adsorption capacities for all adsorbents. However, at 400 ppm CO2, the static method under default conditions (sample mass = 200 mg, equilibration time = 6 min) significantly underestimated CO2 uptake compared to TGA and FB/MS, except for NbOFFIVE-1-Ni. This discrepancy mainly arose because CO2 adsorption at 400 ppm was dominated by adsorption sites, leading to notable differences in mechanisms and saturation times among the adsorbents. By evaluating CO2/N2 selectivity, adsorption heat, physical structure, bed packing depth, and kinetic factors, the study identified mass-transfer limitations as the primary cause of inconsistent results across methods. As a result, the testing conditions for the static, TGA, and FB/MS methods were adjusted to ensure that ZTC-K+ approached saturation during measurement. Under these improved conditions, all three methods produced accurate and consistent CO2 adsorption capacities. This work provides practical guidance for designing and optimizing testing parameters to evaluate adsorbents in ultra-dilute CO2 environments.

Direct air capture (DAC) of CO2 is essential for achieving negative emissions, but conventional adsorbents suffer from low capacity at CO2 concentrations below 400 ppm, high regeneration energy requirements, and humidity-induced deactivation. In this study, an electrochemically charged zeolite-templated carbon (ZTC-Charged) was developed via a rational electrical double-layer design. At 30 degrees C and below 400 ppm CO2, ZTC-Charged achieved a remarkable adsorption capacity of 0.82 mmol/g, more than 400 times higher than that of pristine ZTC (0.0018 mmol/g), while exhibiting superior humidity stability. Comprehensive mechanistic analyses (DSC, XPS, and the Stern model) revealed a synergistic capture mechanism: (i) weak chemisorption via OH--driven bicarbonate formation; (ii) electrostatic polarization generated by K +; and (iii) enhanced physisorption within ultramicropores (0.33-0.38 nm and 0.5-0.7 nm). Crucially, dynamic ion evolution within the electrical double layer under humid cycling produced a unique effect: mobile K + and OH-in the diffusion layer were preferentially consumed in early cycles, while K + anchored in the inner Helmholtz plane and residual OH-in the outer Helmholtz plane acted as a stable reservoir. This allowed ZTC-Charged to retain approximately 60% of its initial capacity after 10 cycles at 75% RH. With low cost, kilogram-scale synthesis, and extremely low regeneration energy, this ZTC-Charged platform established a new mechanistic paradigm for high-capacity, energy-efficient, and humidity-stable DAC adsorbents.

Structuring powdered adsorbents is crucial for the scalable deployment of direct air capture (DAC), yet conventional shaping strategies often compromise low-concentration CO2 capture by increasing mass-transfer resistance. Here, charged zeolite-templated carbon (ZTC-K+) powders are engineered into transport-optimized monolithic architectures to enhance mass transfer and increase effective diffusion coefficients. Conventional densification typically limits DAC performance, whereas a nickel-foam-supported thin-sheet design preserves the intrinsic adsorption capacity of ZTC-K+ by improving interfacial accessibility and shortening diffusion pathways. The nickel foam scaffold also provides mechanical robustness and structural integrity, allowing the adsorbent to maintain its macroscopic shape and retain 82.8% of its initial CO2 capacity after 20 adsorption-desorption cycles. When further assembled into ordered honeycomb and tile architectures and evaluated in a fixed-bed reactor, the structured adsorbents exhibit high selectivities for CO2/N2 and CO2/H2O of 1525.0 and 2.1, respectively. The enhanced CO2 adsorption of ZTC-K+ can be attributed to the synergistic contribution of OH--related chemisorption, K+-induced electrostatic adsorption, and van der Waals physisorption within the microporous structure. Density functional theory calculations reveal that ZTC-K+ exhibits stronger electrostatic interactions with CO2 than with N2, thereby accounting for its high CO2 selectivity. Fluent simulation at 7 m/s showed that the tile-shaped ZTC-K+ delivered the most uniform flow field and the lowest pressure drop, indicating its superior potential for practical CO2 capture. Together, these results show that transport-oriented structural design can bridge the gap between high-performance powdered sorbents and application-ready DAC adsorbents.

This study evaluated zeolite-templated carbon (ZTC) and soft-templated carbon (STC) for direct air capture (DAC) of CO2, examining their synthesis, structural features, adsorption performance, and potential for industrial use. ZTC was produced through chemical vapor deposition using 13 & times; zeolite, revealing a microporous structure (0.72-1.41 nm) and a specific surface area of 2815 m2/g. Conversely, STC prepared via a dual-template glucose system demonstrated a hierarchical pore structure (0.69 nm ultra-micropores and 3.05 nm mesopores) with a surface area of 838 m2/g. Under pure CO2 conditions, both materials had similar adsorption capacities (2.16 mmol/g and 2.09 mmol/g, respectively). However, at 400 ppm CO2, STC outperformed ZTC (0.013 mmol/g vs. 0.0107 mmol/g) due to its radially oriented pores and hollow cavities, which created an "adsorption-enrichment" pathway, thereby improving low-concentration CO2 uptake. Under humid conditions (RH = 75%), both materials exhibited two-stage adsorption kinetics, starting with rapid physical adsorption of CO2, followed by a water-driven carbonation reaction. Water blocking the hierarchical pores and cavities reduced the adsorption efficiency of STC due to its hydrophilic surface. In contrast, ZTC maintained strong physical adsorption and carbonation reactions in humid environments. Additionally, ZTC's lower cost ($29.60/kg vs. $44.36/kg for STC), scalability, and humidity tolerance make it more suitable for industrial CO2 capture.

Toluene, a typical volatile organic compounds (VOCs), poses significant environmental and health risks due to its recalcitrant nature, necessitating the development of efficient low-temperature catalytic oxidation technologies. In this study, stable Sc/Cr bimetallic MIL-101 crystals and their calcined derivatives (Sc/C-Cr2O3) were synthesized via a one-pot hydrothermal strategy. The impact of Sc doping on the physicochemical properties and catalytic performance of the materials was systematically investigated. Incorporating Sc transformed the morphology of MIL-101 from regular octahedrons to irregular shapes with interpenetrating structures and significantly enhanced thermal stability (decomposition temperature increased from 330 degrees C to 450 degrees C). The calcined Sc-doped Cr2O3 derivatives exhibited superior low-temperature catalytic activity; specifically, the 20% Sc-doped catalyst achieved 20%, 50%, and 90% toluene conversion at 127 degrees C, 173 degrees C, and 207 degrees C, respectively. Characterization results (XRD, SEM, BET, XPS, Raman, and H2-TPR) revealed that Sc doping preserved the mesoporous structure and enriched surface adsorbed oxygen species. The strong interaction between Sc and Cr facilitated electron transfer, lowering the apparent activation energy from 88.9 to 51.6 kJ & sdot;mol-1 and thereby boosting catalytic efficiency. This work provides new insights into the design of bimetallic MOF-derived catalysts for VOCs elimination.

Sodium borohydride (NaBH4) is a promising hydrogen storage material, and the development of low-cost and high-efficiency catalysts is critical. In this work, a magnetic Co2-Cu1/Fe3O4@C composite catalyst was successfully prepared via an in situ chemical reduction method, using carbon-coated Fe3O4 (Fe3O4@C) as the support. The results show that the Co2-Cu1/Fe3O4@C catalyst exhibits excellent catalytic activity and recyclability for NaBH4 hydrolysis. At 303 K, the hydrogen generation rate of the reaction reaches 1099.3 mL g-1 min-1, with a turnover frequency value of 16.4. After 8 consecutive catalytic cycles, the catalyst still retains excess 80% of initial catalytic activity. Kinetic studies reveal that the activation energy of NaBH4 hydrolysis over the Co2-Cu1/Fe3O4@C catalyst is 47.81 kJ mol-1. The superior catalytic performance is mainly attributed to the strong synergistic electronic interaction between Co and Cu bimetals, the high dispersion of active components on the support, and the stable core-shell structure of Fe3O4@C. In addition, the magnetic property of Fe3O4 enables the convenient recovery and reuse of the catalyst by an external magnetic field, effectively solving the problems of difficult separation and low recyclability of traditional catalysts and providing a feasible approach for the development of low-cost and high-performance catalysts for NaBH4 hydrolysis hydrogen production.

This study investigated the CO2 adsorption performance of seven adsorbent materials with diverse pore structures and chemical compositions over 213 K to 423 K. For zeolite-templated carbon (ZTC), coconut shell activated carbon (CSAC), MOF-199, and MIL-101, the CO2 uptake increased rapidly in an exponential manner as the temperature decreased. In contrast, coal-based activated carbon (CBAC), 13x, and 5 A zeolite exhibited a slower, linear increase in adsorption capacity. Linear regression and statistical analyses revealed that this difference in temperature sensitivity was likely associated with a shift in the dominant CO2 adsorption mechanism: from adsorption heat-driven interactions at above-ambient temperatures (303-343 K) to a pore-filling mechanism at sub-zero temperature conditions (213-243 K). Further analysis revealed that at 213 K, micropores with diameters up to 2.00 nm contributed to CO2 adsorption, whereas at 243 K, only pores smaller than 1.15 nm remained effective. This indicated that as the temperature increases, the effective pore size for pore filling narrows, and above 273 K, pores larger than 0.85 nm no longer contribute to this mechanism. Moreover, density functional theory (DFT), molecular dynamics (MD) and Grand Canonical Monte Carlo (GCMC) calculations supported that the pore-filling mechanism of ZTC became significant only at relatively low temperatures (< 277 K). Nevertheless, owing to its large nonpolar carbon surface and micropore volume, ZTC exhibited a rapid increase in CO2 uptake once the pore-filling mechanism was activated. This study quantitatively delineated the temperature-dependent transition in CO2 adsorption mechanisms and provided quantitative guidance for selecting and designing CO2 adsorbents optimized for different operating temperatures, particularly for sub-ambient applications such as direct air capture in cold climates.

Efficient capture of structurally diverse chlorinated organic compounds (COCs) from mixed aqueous matrices requires adsorbents that combine accessible porosity with chemically differentiated binding environments. Here, we report an imine-linked covalent organic framework, COF-V, that integrates a conjugated pore surface, imine-rich polar sites and hierarchical micro-/mesoporosity, with a Brunauer-Emmett-Teller surface area of 752.73 m2∙g−1 and dominant pore sizes of 1.92 and 3.78 nm. COF-V rapidly adsorbed 2,4-dichlorophenol (2,4-DCP), chloramphenicol (CAP) and diclofenac sodium (DCF-Na), reaching equilibrium within 30 min and exhibiting Langmuir capacities of 680.84, 773.65 and 665.54 mg∙g−1 at 293 K, respectively. In binary mixtures, competition depended strongly on molecular size and functional-group complementarity. In the ternary system, however, the observed adsorption-retention ratios of 77.15 %, 94.66 % and 83.43 % exceeded those predicted from independent superposition of the corresponding binary inhibition effects, giving compensation coefficients of 1.021, 1.014 and 1.072. This non-additive synergistic compensation arises from complementary occupation of confined and wider pore domains and differentiated use of aromatic and polar binding sites, rather than from adsorption exceeding the corresponding single-solute capacities. X-ray photoelectron spectroscopy and density functional theory calculations reveal a cooperative mechanism involving pore confinement, π-π and n-π interactions, hydrophobic association, hydrogen and halogen bonding, and speciation-dependent electrostatics. COF-V preserved its characteristic framework structure after acid and alkali exposure and retained cycle stability factors above 0.85 after five regeneration cycles. These results identify pore-molecule complementarity and spatially differentiated interfacial interactions as design principles for mitigating competitive adsorption in multicomponent aqueous systems.

This study performed defect engineering on zeolite-templated carbon (ZTC) via different KOH activation methods and quantified the evolution of multiscale defect characteristics and their impact on CO2 capture capacity. Two methods-solution impregnation and ultrasound-assisted KOH activation-were employed to introduce varying degrees of defect structures in ZTC, with performance evaluated through multiscale physical characterization techniques and CO2 adsorption experiments. Results showed that ultrasound-assisted KOH activation effectively generated defect-rich ZTC, enhancing CO2 capture capacity by approximately 35 % compared to unmodified ZTC under dry conditions at 30 degrees C, and by about 22 % under humid industrial flue gas conditions at 75 degrees C. We found that several key factors, i.e., framework defects, curvature changes, and ultramicroporous structures, are linearly correlated with the CO2 adsorption capacity of different activated ZTCs, forming a hierarchical "defect-curvature-porosity" network. On the other hand, no direct correlation was found between overall specific surface area and CO2 adsorption capacity of the ZTCs examined, highlighting the critical role of defect engineering. Kinetic fitting and diffusion models revealed that CO2 adsorption involves a complex multistep nucleation process and surface-to-particle diffusion. This work provides a quantitative framework for defect-mediated CO2 adsorption and lays the foundation for developing tailored carbon materials for efficient CO2 capture.

Condensable particulate matter (CPM) is one of the major emissions of primary particles in coal combustion. The removal efficiency of CPM using the temperature control device (TCD) based on the concept of a heat exchanger application with lower capital cost was investigated in an industrial heating plant. TCD operates without water and flue gas interactions and ensures efficient control of CPM emissions, and it also minimizes the potential ion accumulation in recycled WESP water, which could otherwise hinder the removal of CPM. The total mass and chemical speciation were determined by EPA method 202. The total mass of CPM was removed by 25.7-60.6% after the TCD. The CPM captured by CPM filters (CPMspa) was down to around 15-21% and the FPM also was reduced by around 11-26%. The occurrence of vapor gradient forces and thermophoresis forces could enhance the contact between CPM and water film, which was built up on the surface of the cooling tubes during the process of TCD. Then, part of the CPM was removed with a water film. The low capital and operating cost of TCD can be installed in the industrial heating plant or be set up after the WESP in the coal-fired power plant to enhance the CPM removal efficiency.

Existing studies lack systematic evaluations of how the dry impact and dilution cooling methods influence the finest particle size distribution (0.006-2.5 mu m) of condensable particulate matter (CPM) and its toxic inorganic components (NH4+, SO42-, NO3-, Cl-, Hg, and Se). Thus, the size-resolved formation mechanisms of CPM under both methods in an entrained flow reactor were investigated, the condensation behavior and pollutant distribution differences between surface-aggregated (CPMsur) and spatially suspended (CPMspa) states was quantified, and the mechanisms driving toxic element (TEs) and water-soluble ion partitioning across particle sizes was elucidated. The dry impact method overestimated ultra-fine CPMspa (0.006 mu m) concentrations by 265-fold compared to dilution cooling, primarily due to water-soluble gas absorption and suppressed heterogeneous condensation. These disparities diminish with increasing particle size, and the differences become the same order of magnitude in the ultra-micron range. Dilution cooling redistributed water-soluble ions (e.g., NH4 & thorn; surface aggregation decreased from 90.46 % to 78.16 %) and TEs (e.g., Se spatial suspension increased from 66.2 % to 87.2 %), amplifying their environmental mobility. The dilution cooling method showed peak concentrations of Hg (0.0134 mu m) and Se (0.0212 mu m) in a smaller particle size region. Mechanistically, the dilution cooling method promoted heterogeneous condensation of semi-volatile species into ultra-fine and sub-micron CPMspa, while the dry impact method favored surface adsorption and retention of water-soluble ions and TEs in larger aggregated particles. These findings resolved the long-overlooked methodological biases in CPM measurement and demonstrate that sampling techniques directly dictated the accuracy of pollution assessments by influencing water-soluble gas absorption and particle redistribution mechanisms. This work established a framework for selecting context-appropriate methods to refine emission control strategies and regulatory policies.

This study investigates the CO2 capture capacity and mechanisms for three physical adsorbents in dry and humid conditions with a comprehensive experimental and analytical approach. Zeolite templated carbon (ZTC) with a high specific surface area and an ordered structure was synthesized and used, and MOF-199 and commercial 13X zeolite were also selected for comparison purposes. The combined thermogravimetric analysis (TGA) and fixed- bed reactor (FBR) test methods demonstrated that ZTC exhibited the most rapid CO2 adsorption rate and the slowest H2O adsorption rate compared with MOF-199 and 13X zeolite. In a humid environment, the ZTC increased its CO2 adsorption by 19.7 % compared to dry conditions, while the CO2 adsorption capacity for MOF199 and 13X zeolite decreased by 16.7 % and 15.4 %, respectively. In-situ infrared spectroscopy revealed the formation of multiple distinct carbonate species at 1685, 1619, 1436, 1385, and 1060 cm-1, which increased the CO2 adsorption capacity for ZTC. The density functional theory (DFT) results also supported the formation of carbonate species on the surface of ZTC under humid conditions. Meanwhile, the lowest desorption temperature was exhibited by ZTC under humid conditions, occurring at 101 degrees C after reaching CO2 and H2O co-adsorption saturation. While DSC results show a higher desorption temperature, approximately 200 degrees C, for MOF-199 and 13X zeolite. After ten adsorption/desorption cycles, the CO2 adsorption capacity of ZTC remained constant. The results here demonstrate that ZTC has the potential to be an effective adsorbent material for CO2 capture in humid environments.

To enhance the elimination of trace elemental mercury (Hg-0) from coal-fired flue gas, silver nanoparticles (AgNPs) were directionally anchored into the pores of MIL-101(Cr) using the double-solvent method (DSM) to achieve a highly dispersed fixed-bed adsorbent Ag@MIL-101 at room temperature. Various experimental characterizations were conducted to verify the Physical and chemical properties of the adsorbent, and fixed bed adsorption experiments evaluated the Hg-0 removal efficiency. Within the temperature range of 30-70 degrees C, Ag@MIL-101(Cr) achieved nearly 100 % Hg-0 removal efficiency, maintaining stability even at high concentrations of SO2 (1500 ppm) and H2O (9 %). Density functional theory (DFT) revealed that the introduction of AgNPs greatly enhanced the adsorption capacity of MIL-101(Cr) for Hg-0, with an evident electron exchange between Ag and Hg, and the adsorption energy changed from -36.91 kJ/mol to -68.59 kJ/mol. The interaction between Ag and Hg was a relatively strong weak interaction, which allowed for easy desorption at moderate temperatures (similar to 200 degrees C), significantly saving energy. Tests conducted with flue gas from an actual coal-fired power plant demonstrated that 2Ag@MIL-101(Cr) exhibited superior Hg-0 removal efficiency compared to activated carbon at the WESP outlet under low-temperature (about 50 degrees C) and high-humidity conditions, providing an efficient and economical solution for flue gas purification.

In this study, CeO2 as a carrier and Pd-loaded catalysts were prepared by mechanochemical with different treatment times, and monatomic catalysts (Pd1-CeO2-10 h) were prepared by ball milling for 10 h. The Pd1-CeO2-10 h single-atom catalyst had the highest catalytic activity by fixed-bed reaction tests on toluene, benzene, and chlorobenzene, reaching 90

Metal-organic frameworks (MOFs) are a novel class of porous materials characterized by high surface area, high porosity, and tunable structure, possessing immense application potential. Many synthesis methods have been developed for MOFs, such as chemical, hydrothermal, mechanochemical, and microwave-assisted methods. However, their commercialization faces significant hurdles due to the high synthesis costs that mainly include the material costs of organic ligands, metal precursors, solvents, and energy consumption during prolonged reaction times. The synthesis conditions and material selections also impact the MOF structural properties, such as specific surface area and porosity. Hence, in this paper, we propose a machine learning-based multiobjective framework to identify optimal MOF synthesis conditions while achieving desired structural properties. Leveraging synthesis data from the SynMOF database and large-scale commercial raw material cost data, we developed machine learning predictive models. Pareto-optimal synthesis routes maximizing SSA while minimizing cost were identified using the nondominated sorting genetic algorithm II (NSGA-II). Subsequently, k-Nearest Neighbors (k-NN) was employed to retrieve practical optimal synthesis conditions by matching the optimized abstract features with those of metal types, solvent types, and ligand descriptors. Finally, a Bagging-integrated positive-unlabeled learning model was employed to screen solutions with a production feasibility probability exceeding 0.7. This comprehensive framework provides a strategic pathway for synthesizing high-performance, low-cost MOFs.

This study examined volatile organic compound (VOC) emission characteristics in three supercritical coal-fired power plants (660 MW, 600 MW, and 330 MW units), with five tasks: the effect of load, excess air ratio, combustion flame location (adjust the burners), air pollution control device (APCD) operational scenarios, and co-firing with biomass (10 %) and sludge (10 %), all of which were carried out in situ. Each task included two similar setups on the boiler and APCDs for comparison. A 1.4 MW pilot scale was included to provide the most challenging tasks, which were difficult to conduct in the power plant. Around 60-70 % of VOC was reduced by optimizing the boiler combustion conditions, which was most influenced by increasing the flame center height and adjusting the secondary air ratio. The rest (30-40 %) of the VOC entered the APCD's system from the boiler, and the central portion of the VOC in the tail gas was effectively oxidized through the catalytic oxidation process in the SCR system. The ESP had negligible removal effects on VOC, and the high-voltage discharge enhanced the re-emission of VOCs from fly ash. Thus, combustion condition optimizations combined with APCDs could synergistically remove over 90 % of VOCs in most power plants. In addition, the blending of biomass and sludge will increase the production of VOCs. The study is crucial for achieving clean coal power production and significantly reducing VOC emissions.

Pelletized sorbent particles were preferred over powders in large-scale CO2 capture applications since pelletized adsorbents with high mechanical strength can improve bed stability, reduce reactor pressure drop, reduce adsorbent particle attrition, and reduce equipment clogging. This study examines the pelletization of zeolite templated carbon (ZTC) as a promising CO2 adsorbent with a comprehensive experimental and analytical approach. Four binders, namely CMC-NH4, CMC, SBR, and PTFE, were employed to pelletize ZTC, and it was found that the ZTC pelletized by the CMC-NH4 binder exhibited the highest mechanical strength and CO2 adsorption capacity. CMC-NH4 on the ZTC surface has the strongest binding energy (-48.52 kcal mol- 1) and it binds the ZTC particles together via a line-type connection, providing ZTC@CMC-NH4-10 wt% pellet the highest mechanical strength of 3.0 MPa. Meanwhile, the CMC-NH4 binder enhances ZTC surface polarity and provides new adsorption sites, increasing the pellet's CO2 adsorption capacity. This was particularly true at a low CO2 concentration of 400 ppm, where the adsorption capacity of the pellets was 6 times that of ZTC powder. A generalized computationally accelerated binder selection framework was then developed by correlating the binder selection criteria for CO2 capture with computationally attenable pellet characteristics for different binders.

This study examines the diffusion mechanisms and the enhanced CO2 adsorption capture capacity of hightemperature ammonia-treated zeolite-template carbon (ZTC), in both concentrated and diluted CO2 environments. The bare ZTC materials were synthesized with chemical vapor deposition (CVD) to achieve uniform microporous structures. The bare ZTC was doped with nitrogen atoms by high-temperature ammonia treatment. The experimental results showed that the ZTC-NH3 heat treated at 800 degrees C adsorbed 2.58 mmol/g of CO2 under the 100 % CO2 environment which was 22.2 % higher than that of ZTC-Bare. In 400 ppm CO2 atmosphere, the CO2 adsorption capacity of ZTC-800NH3 was 6 times that of ZTC-Bare. Through microscopic characterizations and theoretical calculations, the improved adsorption performance of ZTC-NH3 was attributed to its more developed microporous structure and the doping-induced polar functional groups. Different diffusion adsorption mechanisms for different ZTCs under pure and dilute CO2 environments are elucidated. Finally, the experiment results from multiple adsorption-desorption cycles demonstrate the good cyclability and stability of ZTC800NH3.

Organic pollutants are acknowledged as one of the primary environmental hazards in the atmosphere, posing a significant threat to human health and the environment. This work provides a critical review of the recent research on organic pollutants from stationary coal-burning sources, including an overview of the effect of coal composition and coal source, the types of organics material in coal, the generation of organic pollutants during coal combustion, emission of organic pollutants, co-removal by air pollution control devices (APCDs), and the technologies used to remove organic pollutants from coal-fired power plants (CFPPs). Field sampling and analysis showed that the organic pollutants produced from coal combustion processes are mainly composed of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and organic components in condensable particulate matter (CPM). The VOCs and CPM are mainly discharged into the atmosphere as part of the gas and particulate phases, respectively, whereas, PAHs are mainly concentrated in fly ash and bottom ash. The generation of organic pollutants during coal combustion is mainly affected by coal grade, temperature, heating rate, residence time, and pressure. Considering that the flue gas temperature and composition can vary from one CFPP location to another, the choice of the sampling methods is based on the specific needs of a CFPP. Because, the selection of a sampling method can significantly affect the final results and should be given special attention. Typical sampling methods for VOCs, PAHs, and CPM are summarized and their advantages and disadvantages are compared. The adsorption tube sampling method is more suitable for the sampling of VOCs because it is not limited by the volume and miscellaneous components of the flue gas. EPA Method 0010 and the dry impactor condensation method (EPA Method 202) are more suitable for sampling PAHs and CPM in flue gas due to their higher accuracy. The APCDs in CFPPs have organic pollutants co-removal abilities besides those for conventional pollutants. As a result, they can remove VOCs, PAHs, and CPM at efficiencies of 55.8–87.6 %, 74.7–89.8 %, and 36.3–81.5 %, respectively, with corresponding emission concentrations of 0.058–16.29 mg/m3, 0.42–43.3 μg/m3, and 5.9–65.1 mg/m3. Based on current publicly reported data, the VOCs, PAHs and CPM contents emitted by global coal-fired power plants are estimated to be 88.1 Gg, 6.76 Gg (2.22 Gg in flue gas and 4.54 Gg in fly ash), and 600 Gg (organic components: 328 Gg, inorganic components: 272 Gg), respectively. Among the many removal technologies reviewed: include improved selective catalytic reduction (SCR) catalysts; and an advanced oxidation process (AOP) combined with an SCR or with a wet flue gas desulphurization (WFGD) unit respectively are two potentially useful technologies for future use in CFPPs. The information collected and presented in this review will help in the formulation of air pollution control policies and the development and application of efficient removal technologies.