Cu-SSZ-13 has been commercially utilized as NH3-SCR catalyst for diesel vehicles, yet its performance is hindered at low-temperatures and further inhibited by NO2. These issues could be mitigated by MnOx-CeO2 modification, but the specific roles of MnOx and CeO2 remained unclear. Through a combination of characterization methods, TPD/TPSR and DRIFTS, a promotional mechanism was proposed. In the standard SCR reaction, MnOx and CeO2 modification facilitated NO oxidative activation by reducible Mn species and active oxygen species, promoting the L-H pathway by nitrite/nitrate species reacting with adsorbed NH3 species. MnOx modification proved particularly effective for NO oxidative activation, generating monodentate nitrate and nitrite as active intermediates, thereby contributing to the superior low-temperature activity. Although the MnOx and CeO2 modification also reduced high-temperature activity of Cu-SSZ-13, the MnOx-CeO2 modification maintained high-temperature activity of Cu-SSZ-13 owing to the synergistic interaction between MnOx and CeO2 on Cu-SSZ-13. In the fast SCR reaction, MnOx modification promoted the reduction of NH4NO3 and inhibited N2O release by producing bidentate nitrate and monodentate nitrate, and CeO2 modification enhanced the reactivity and instability of NH4NO3, mitigating NH4NO3 inhibition on NO reduction. This work provided an improved understanding of the standard SCR and fast SCR reactions of Cu-SSZ-13-based catalysts at low temperatures.

The utilization of sodium bicarbonate (NaHCO3) as a solid reactant for the mitigation of acidic pollutants from industrial flue gas streams represents a straightforward and efficient process solution. The paper addresses the problem of medium-to high-temperature flue gas dechlorination by investigating the effects of base particle size, temperature, water vapour and different flue gas fractions on the removal of HCl from simulated flue gases by NaHCO3 in a fixed-bed reactor, and the effects of the presence of SO2 and H2O on the chlorination reactivity of NaHCO3 are also investigated by density functional theory (DFT) calculations. The adsorption results implied that 300 degrees C was the optimum temperature for HCl removal by NaHCO3 in a reaction system not affected by SO2 or H2O; The higher the HCl concentration, the greater the HCl capture, but when the concentration is too high, due to the dense product layer makes the HCl gas molecules to the internal diffusion is blocked, the dechlori-nation effect becomes poor. The smaller the particle size of NaHCO3, the better the removal of HCl. In the system containing SO2, theoretical calculations based on density functional theory show that the presence of SO2 affects the exchange of electrons between the Cl atoms in HCl and Na2CO3, and the bonding ability of the Na-Cl bond is weakened, thus weakening the dechlorination ability of Na2CO3; However, SO2 has little effect on HCl removal at the same concentration, due to the fact that HCl rapidly consumes the easily accessible surface of the absorber and SO2 must diffuse deeper into the particles for the reaction to occur, suggesting a preferred reaction between HCl and NaHCO3. After the addition of H2O, the adsorption energy of HCl on the surface of Na2CO3(2 0 0) was greater than the adsorption energy of SO2 on the surface of Na2CO3(2 0 0), and HCl was preferentially adsorbed on the surface of Na2CO3(2 0 0), which preferentially reacted with the absorber. These findings help to elucidate the principle of HCl absorption by NaHCO3 and the competition mechanism between HCl and SO2, and improve the theoretical knowledge of acid gas absorption by NaHCO3.

Achieving decarbonization in the steel industry is of paramount importance for global carbon neutrality. Given the unavoidable generation of calcium -containing steel slag and carbon -rich flue gas emissions in the steelmaking process, steel slag carbonation is considered a CCUS technology capable of achieving pollution and carbon reduction in the steel industry. This study conducts a life cycle assessment (LCA) of the environmental impacts generated within the system boundaries of mainstream hot braising steel slag treatment and a novel carbonation steel slag approach. Results of the research demonstrate that the carbonation route based on carbon capture, utilization, and storage (CCUS) technology reduces the global warming potential (GWP) by 480% compared to the mainstream hot braising route, yielding -76.78 kg CO2 eq./t steel slag. The carbonation route also mitigates the environmental impact of pollutant emissions; however, it introduces a burden shifting associated with energy and resource consumption. Furthermore, to tackle the challenges of industrial application of steel slag carbonation, this study has explored upgrading schemes and proposed a future carbonation steel slag route that achieves process upgrades. By enabling carbonation of flue gas and improving carbonation efficiency, this route is forecasted to elevate the potential of carbon footprint reduction from 5% to 15% throughout the entire life cycle of steelmaking process. The study confirms that steel slag carbonation is a viable carbon -negative technology, delivering a substantiated CCUS solution for achieving co -benefits of pollution and carbon reduction in the steel industry.

Activated coke (AC) has been widely applied in air pollution control; however, improving its low -temperature NH 3 -SCR activity remained challenging. In this study, we modified AC with La-Mn-Fe oxides, of which the 6 %La 0.45 - Mn 0.15 - Fe 0.4 /AC catalyst exhibited the highest low -temperature activity. It exhibited more than 90 % NO x conversion at 150 -300 degrees C with high N 2 selectivity and good resistance to H 2 O and SO 2 . The large surface area and pore volume was maintained and the surface functional groups were increased by the interaction between the modified components and AC support. Mn addition could increase the Fe 3 + /Fe ratio and the amounts of acid sites. La addition could facilitate gaseous O 2 adsorption and modulate the intensity of Lewis acid sites, improving oxygen supplementing ability and N 2 selectivity. The enhancement of the redox properties, the amount of Lewis acid sites and the active adsorbed oxygen by the synergistic interaction among La, Fe and Mn oxides promoted the NH 3 adsorption and NO oxidation, thereby enhancing the low -temperature activity through both E -R and L -H reaction pathway. These findings provided an efficient strategy for designing AC catalysts for low -temperature NH 3 -SCR technology.

Developing efficient and stable catalysts for synergistic removal of NOx and dioxin has always been key for controlling air pollution.

涉及天然气、煤制气和石油裂解气等气体的生产过程会产生大量含硫酸气,其中硫化氢(H2S)既是一种剧毒气体,也是重要的硫资源.随着环保和减碳政策的实施,含硫酸气中的H2S脱除问题受到广泛关注,低共熔溶剂作为一种新兴的溶剂被应用到含硫酸气的净化中.分析、总结了低共熔溶剂的合成方法及性质,综述了低共熔溶剂在H2S脱除方面的机理研究及应用,讨论了H2S脱除技术所面临的问题,并对低共熔溶剂作为脱硫剂的发展趋势进行了展望.

In this paper, a Co–Fe LDO catalyst was prepared by combining K2Cr2O7 and Cr(NO3)3 to modify the LDH precursor.

Deep eutectic solvents (DESs) have properties that make them suitable candidates to be used as entrainers for extractive distillation. In the previous work, it was proven that DES(1:2) (tetrabutylammonium bromide: levulinic acid, 1:2, molar ratio) can break the cyclohexane-benzene azeotrope. In the present work, the HBA and HBD ratio and molar concentration of DES were optimized to obtain a better constitute and condition of DES to be utilized in cyclohexane and benzene extractive distillation. The physical properties and structure of the prepared DESs were characterized. Vapor–liquid equilibrium data of the ternary system (benzene + cyclohexane + DESs) were also measured at atmospheric pressure. All experimental equilibrium data were correlated with Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models, from which the coefficient of determination (R2) of the three pseudo-ternary systems fitting was calculated. From the obtained results, the best HBA and HBD ratio in the DESs is elucidated as 1:2, the best molar concentration of DES is 0.1, and the NRTL model predicts the experimental data more accurately than the Wilson and UNIQUAC models. From the derived mechanism, the formation of stronger hydrogen bond and π–π bond interactions between DES and benzene is obtained when HBA and HBD ratio in DES is 1:2. In other conditions, the azeotrope cannot be broken, or the efficiency is low. The present work provides an environmentally friendly method to separate aromatic/aliphatic mixtures and act as a guide for further study of DESs in extractive distillation.

Metal–organic frameworks (MOFs) have been widely used to remove organic/toxic compounds from waste water. Ciprofloxacin (CIP) has been detected in surface and waste water, which is harmful to aquatic organisms and human body. Herein, MIL-101(Cr)-HSO3 was synthesized by solvothermal method and its structural features were characterized by XRD, SEM, FTIR, N2 adsorption–desorption analysis at 77 K and zeta potential. Then, the CIP adsorption performance of MIL-101(Cr)-HSO3 was investigated, in which the effect of adsorbent dosage, contact time, pH and ionic strength were explored. MIL-101(Cr)-HSO3 showed the highest adsorption capacity when the adsorbent dosage was 0.1 g/L and the pH was 8.0. The observation from the effects of pH and ionic strength suggested a stronger electrostatic interactions between CIP and MIL-101(Cr)-HSO3. The pseudo-second-order model fitted the adsorption kinetics data of MIL-101(Cr)-HSO3 well. Moreover, the equilibrium adsorption data of MIL-101(Cr)-HSO3 followed the Langmuir model, indicating a mono-layer adsorption of CIP onto surface of MIL-101(Cr)-HSO3. The calculated maximum CIP adsorption capacity from Langmuir model was 564.9 mg/g, which was higher than the reported materials. Besides, the equilibrium adsorption data were fitted to the Tempkin model with r2 = 0.9880, which also suggested a stronger electrostatic interaction between CIP and MIL-101(Cr)-HSO3. Finally, the introduced sulfonic acid group made the material more negatively charged on the surface, which benefited the adoption of CIP via stronger electrostatic interactions resulting the enhanced adsorption capacity of CIP. The results show that the MIL-101(Cr)-HSO3 is a promising candidate for removal of CIP and introducing proper functional groups on organic linker is a convenient way to obtain MOFs with better performance for a specific application.