The ammonia selective catalytic reduction (NH3-SCR) and CO oxidation provides a promising route for the simultaneous removal of NOx and CO emitted from steel industry. However, the majority of catalysts suffer from poor performance and SO2 resistance at low temperature (<= 260 degrees C), which limit their practical application. To this end, an efficient catalyst of Pt and V species decorated WO3-TiO2 (Pt-V/WTi) material is synthesized. By providing dual active sites to synergistically accelerate the adsorption of NO and CO, the Pt-V/WTi catalyst can achieve a maximum NOx conversion of 92 %, while achieve 93 % CO conversion at 260 degrees C and a GHSV of 120 000 h- 1. Results from in situ Diffuse Reflectance Infrared Fourier Transform spectroscopy of CO (CO-DRIFTs), Xray photoelectron spectroscopy (XPS), temperature programmed reduction (H2-TPR) and Raman spectroscopy illustrate Pt acts as an electron donor to V to strengthen the interaction between Pt and V over Pt-V/WTi, facilitating the NH3-SCR and CO redox cycles Additionally, the formation of Pt-O-V species regulates the surface electronic state of the catalyst and creates an optimal interface for the adsorption of reactant molecules. Furthermore, we studied the mechanisms of CO oxidation and NH3-SCR. In situ DRIFTs analysis shows that NH3- SCR over Pt-V/WTi follows the Eley-Rideal mechanism, while CO oxidation adheres to the Mars-van Krevelen mechanism. The overall results can guide the simultaneous control strategy of CO and NOx in the sintering process of steel.

Identification of active sites governing the performance of indoor formaldehyde (HCHO) oxidation at ambient temperature and low humidity is crucial for developing improved catalysts, but remains challenging. It has recently been discovered that the effective dissociation of water is of importance for HCHO oxidation at low humidity. Here, we have elaborately designed a Pt supported on three-dimensionally ordered mesoporous CeO2 catalyst (Pt/kit-CeO2). The Pt/kit-CeO2 catalyst achieves similar to 95 % CO2 yield for a long time. The results indicate that the abundant oxygen vacancies and single coordination-unsaturated Ce sites on mesoporous CeO2 enhance H2O dissociation, leading to the generation of a substantial amount of terminal hydroxyl groups (OHt). These OHt groups promote the oxidation of intermediate dioxymethylene (DOM) and formate species, thereby regulating the catalytic activity. Additionally, the dispersed Pt facilitates the activation of O-2, generating active oxygen species (O*) that work synergistically with OHt groups to promote the conversion of formates into CO2. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) further elucidated the mechanism of catalyst promoting HCHO oxidation: HCHO (+O*) -> DOM (+OHt) -> HCOO-/HCOOH (+OHt/O*) -> CO32--> CO2. We anticipate that this knowledge will inspire the development of Pt-based catalysts specifically tailored for low humidity.

Efficient formaldehyde (HCHO) removal at low humidity is currently challenging due to hardly water dissociation. The strong metal-support interaction (SMSI) between Pt and CeO2 would facilitate the dissociation of water efficiently. Here, we designed Pt/CeO2-UiO catalyst, where CeO2-UiO has abundant oxygen vacancy (O-v) defects. Pt/CeO2-UiO had achieved superior formaldehyde oxidation and CO2 yield of similar to 95 % under low humidity conditions (relative humidity = 30 %). The abundance of O-v defects endowed the material with a highly dispersed distribution of Pt on CeO2-UiO, thus creating much more Pt-O-Ce interfaces than Pt/CeO2. The increase of the Pt-O-Ce interface induced SMSI, boosting the O-2 activation capacity and, more importantly, promoting the production of terminal hydroxyl groups (OHt). In situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) showed that the activated oxygen promoted the production of OHt and was cooperatively involved in the degradation of HCHO. Effective generation of OHt endowed Pt/CeO2-UiO with excellent activity for HCHO elimination at ambient temperature and low humidity. Synopsis: Formaldehyde degradation under low-humidity conditions is limited. In this study, SMSI was used to enhance the ability of Pt/CeO2 catalysts to utilize water, thereby improving the efficiency of formaldehyde degradation under low-humidity conditions.

Flue gas desulfurization facilities produce flue gas desulfurization ash (FGDA), which has ecological and economic benefits. In this article, we explored the possibility and impact of using FGDA as the sole reinforcing filler to mechanically improve epoxidized natural rubber (ENR). The influence on the properties of the composites was examined. FGDA exhibits good interfacial interaction and compatibility with ENR, which improves the mechanical properties of ENR. When 15 phr FGDA was added, the tensile strength of the composites increased by approximately 41.4% compared with that of pure ENR. This work demonstrates the possibility of using FGDA as an effective and sole reinforcing material to enhance the properties of rubber materials.HighlightsFGDA improves the mechanical properties of ENR as a sole reinforcing filler.FGDA reacts with ENR during vulcanization, enhancing compatibility.Adding 15 phr FGDA to ENR increases the tensile strength by 41.4%. This article investigated the possibility of reinforcing polar rubber with flue gas desulfurization ash (FGDA) as the sole filler. The results show that FGDA effectively improves the mechanical properties and thermal stability of epoxidized natural rubber.image

以脱硫灰为补强填料,采用直接共混法制备天然橡胶(NR)/脱硫灰复合材料,研究了不同用量的脱硫灰对NR/脱硫灰复合材料性能的影响.结果表明,脱硫灰可以赋予NR复合材料良好的热稳定性,提高NR复合材料的力学性能,改善NR复合材料的综合性能.将脱硫灰作为一种新型补强填料,对实现脱硫灰的资源再利用具有积极意义.

将干法脱硫灰掺入轻质抹灰石膏砂浆中,探究了干法脱硫灰对石膏砂浆凝结时间、流动度和强度的影响及其与不同缓凝剂的适应性.结果表明,掺入干法脱硫灰后降低了缓凝剂XQ的缓凝效果和流动度.干法脱硫灰中含有的氢氧化钙是造成缓凝剂XQ缓凝效果降低的主要原因.当氢氧化钙掺量超过0.2％时,石膏砂浆的凝结时间明显缩短、流动度下降,选择耐碱性的缓凝剂SH可解决该问题.当干法脱硫灰占比为30％时,石膏砂浆的7 d抗压、抗折强度均得到提高,掺加缓凝剂SH可有效延长凝结时间、增大流动度.

《大气污染控制工程》是环境工程专业的核心课程,在新工科背景下培养高素质环保工程技术人才具有十分重要的作用.我们根据新工科人才培养精神,按照工程教育专业认证具体要求,结合"课程思政",明确了该课程的教学目标,开展了新工科背景下的课程教学改革实践,课程教学质量得到了巩固和保障,教学内容实行了模块化优化,教学组织形式以学生为中心,课程评价制度进一步完善,课程教学持续改进.

Flue gas desulfurization ash (FGD) is a byproduct of flue gas desulfurization facilities. Its comprehensive utilization has attracted increasing interest. In this work, FGD is used as the reinforcing filler to improve the mechanical properties of carboxylated styrene-butadiene rubber (XSBR). The effects of FGD on the curing characteristics, microtopography, and mechanical properties of the composites were studied. The results indicated that FGD can be uniformly dispersed in XSBR and effectively improve the mechanical properties of XSBR composites. The tensile strength of the XSBR/25FGD composite reaches 14.0 MPa, approximately 19.7% higher than that of pure XSBR. Even if the incorporation of FGD reaches 45 phr, the tensile strength is still higher than that of pure XSBR. The composites obtained a lower rate of thermal degradation than XSBR. The DMA properties of the composites may be improved by the appropriate amount of addition. This work provides a new method for making more effective use of FGD in the polymer field, which has significant economic and environmental benefits.

研究了氧化脱硫灰作为水泥缓凝剂的可行性.在分析了氧化脱硫灰理化性质的基础上,评估了氧化脱硫灰、氧化脱硫灰和脱硫石膏复配用作水泥缓凝剂对水泥细度、安定性、凝结时间和强度的影响.结果表明:氧化脱硫灰对水泥细度、安定性无不利影响;对水泥的缓凝作用与脱硫石膏相当;采用氧化脱硫灰、氧化脱硫灰和脱硫石膏复配作为水泥缓凝剂的3 d和28 d强度与脱硫石膏相当或优于控制配方.因此,氧化脱硫灰可用作水泥缓凝剂.

FeOx–CeO2–V2O5/TiO2 catalyst showed higher N2 selectivity and resistance to SO2 and H2O than MnOx–CeO2–V2O5/TiO2 catalyst due to their different physicochemical properties. The interaction of Fe, Ce and V oxides and reaction mechanism were explored.

In this study, Manganese oxide (MnOx) was supported on activated coke modified by (NH4)(2)S2O8 (ACs) to obtain novel MnOx/ACs catalysts with high NOx removal performance by excessive impregnation method. The influence of precursor and loading amount of MnOx on the catalytic efficiency were studied. The Mn3O4 supported on ACs samples prepared with manganese acetate tetrahydrate as precursor and the loading amount of 8% Mn is the most effective in NOx removal among modified samples and its removal efficiency is 97% at 180 degrees C. And the adsorption state and reaction behaviors of NH3, NO and O-2 on MnOx/ACs catalysts were measured by in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) in different conditions in order to study the effect of MnOx and the reaction mechanism. The results suggested that Eley-Rideal and Langmuir-Hinshelwood mechanism existed simultaneously for the selective catalytic reduction of NO over the MnOx/ACs catalyst. (C) 2020 Energy Institute. Published by Elsevier Ltd. All rights reserved.

将CaSO3加热氧化为CaSO4是提高半干法脱硫灰综合利用率的重要途径,而在众多热处理工艺中,回转窑因其能耗低、受热均匀、产品性能稳定等优势是最有望实现工业化的技术之一.本文模拟工业回转窑的工艺过程,对半干法脱硫灰在回转窑不同工况条件下CaSO3的氧化与分解特性进行了试验研究,分析了温度、停留时间、氧气浓度对CaSO3氧化与分解特性的影响.结果表明:随着煅烧温度的增加,CaSO3氧化率显著增大,当温度达到600℃时,CaSO3氧化率达到了60.48％,而CaSO3分解率随温度变化不大;降低回转窑转速有利于提高CaSO3的氧化率,但影响较小;回转窑内氧气浓度对CaSO3的氧化有显著影响,当温度为450℃,氧气浓度由14.0％ 增加至17.5％ 时,CaSO3氧化率由12.18％ 增加至71.95％.

CFB-FGD脱硫灰中CaSO3·0.5H2O含量可达60％以上,对水泥性能影响与石膏有较大不同.对比研究表明,CFB-FGD脱硫灰在适宜掺量时对水泥凝结时间、抗压强度的影响与石膏的影响相当,但超量时容易导致抗压强度显著降低;与适量的石膏复掺性能会得到改善;随脱硫灰掺量的增加,对水泥与减水剂的相容性以及对水泥的体积稳定性无明显不良影响.CaSO3·0.5H2O与C3A反应生成C3A·CaSO3·11H2O,与AFm相类似,呈板片状.CaSO3·0.5H2O与同量的C3A反应会生成较多量的类AFm物,而非柱状、针状的AFt,是导致CaSO3·0.5H2O具有延缓水泥水化的作用,但不如石膏,且超量掺加时易对强度造成不良影响的主要原因.

The poisoning effect of single elements on commercial V2O5-WO3/TiO2 catalysts has been studied in the past decades. In this study, the combined effects of two multi-element systems (phosphorus-potassium and phosphorus-lead) on V2O5-WO3/TiO2 catalysts were studied by diverse characterizations. The results show that potassium and lead can result in the deactivation of catalysts to different degrees by reacting with active acid sites and reducing the amount of V5+. However, phosphorus displays slight negative influence on the NOx conversion of the catalyst due to the comprehensive effect of reducing V5+ amount and generating new acid sites. The samples poisoned by phosphorus–potassium and phosphorus–lead have higher NOx conversion than that by potassium or lead, because doped potassium or lead atoms may react with new acid sites generated by phosphate, which liberates more V–OH on the surface of catalysts and reduces the poisoning effects of potassium or lead on vanadium species and active oxygen species.

Direct leaching with NaOH can be an economically acceptable method for vanadium (V) and tungsten (W) recovery from spent selective catalytic reduction (SCR) catalysts. However, different chemical-physical characteristics of catalysts would affect the V and W leaching. In this paper, the V and W leaching behavior of various sources of SCR catalysts with a local difference (yellow and gray color) were systematically investigated with alkali leaching solution under ambient pressure. Different leaching efficiencies from yellow and gray color areas were correlated with oxidation states and species of V and W on catalyst surfaces, as characterized by X-ray photoelectron spectroscopy (XPS), Raman, Fourier transform infrared spectroscopy (FTIR), and other analytic methods. For the V leaching efficiency, the samples from a gray area of catalysts (40.0–51.0%) were lower than that from the yellow area (66.8–69.8%). The higher molar ratio of V3+ and a lower molar ratio of V5+, and the lower total V content on the surface of the samples from the gray area could be the main reasons for the lower V leaching efficiency. As for the W leaching efficiency, the samples from the gray area (44.6–57.3%) were slightly higher than that from the yellow area (38.0–52.6%) of catalysts. The less total W content of surface species and stronger interaction among V–W–Ti of yellow area samples resulted in the lower leaching efficiency. These differential leaching efficiencies needed to be taken into consideration for recovering V and W from spent SCR catalysts.

研究了循环流化床锅炉配套干法脱硫装置再脱硫所产生的脱硫灰作为水泥掺合料的可行性.评估了干式和湿式球磨对脱硫灰的细度、成分和活性的影响.结果表明:湿磨对脱硫灰磨细更有效,磨细90 min后中位粒径约3μm,磨细对脱硫灰的成分影响不大;磨细可有效提高脱硫灰的活性,并实现超细脱硫灰替代20％波特兰水泥的胶砂早期强度与控制配方相当,28 d后胶砂强度优于控制配方,水泥混凝土在7 d后抗压强度高于控制配方,28 d抗压强度达到控制配方的120％;磨细对胶砂尺寸稳定性影响较小.

以来自国内不同地区51个循环流化床干法脱硫工艺所产生的不同时间段的120个干法脱硫灰的元素组成分析结果为研究对象,利用SPSS软件对数据进行主成分分析评价.通过评价可知,干法脱硫灰中的SiO2、CaO、Al2O3、SO3和LOI的波动性最大,Fe2O3、Na2O、MgO、K2O和Cl的波动性较小,但有些干法脱硫灰由于使用工业盐水,可能会导致Cl含量很高.通过主成分分析可知,SiO2、Al2O3和Fe2O3三个指标之间的关联性较大;CaO、SO3和LOI三个指标之间的关联性较大.当来自钢铁厂的脱硫灰综合得分小于0.6时,则表明其取样、运行参数、工况或吸收剂品质可能存在问题;当燃煤锅炉脱硫灰所产生脱硫灰的综合得分大于0.6时,则表明其运行情况可能存在不经济.

以脱硫灰、环氧树脂为原料通过"脱硫灰浆复合法"制备了一系列新型脱硫灰/环氧树脂复合材料,探讨了环氧树脂稀释液中稀释剂用量、环氧树脂胶液与脱硫灰的配比、环氧树脂稀释液与固化剂的配比对新型脱硫灰/环氧树脂复合材料拉伸强度、断裂伸长率、冲击强度等力学性能的影响.结果表明:当环氧树脂中稀释剂用量在25％,环氧树脂胶液/脱硫灰质量比1:1.5,环氧树脂稀释液/固化剂质量比在1:0.24时,脱硫灰/环氧树脂复合材料的综合性能及性价比较高.

The accumulation of NH4HSO4 leads to the deactivation of commercial V2O5-WO3/TiO2 catalyst (VWTi) in practical application. The commercial catalyst is modified with 0.3 wt. % Ce and 0.05 wt. % Cu (donated as VWCeCuTi), and its sulfur resistance is noticeably improved. After loading 20 wt. % NH4HSO4, the NOx conversion of VWCeCuTi-S remains 40% at 250 °C, higher than that of VWTi-S (25%). Through a series of characterization analyses, it was found that the damaged surface areas and acid sites are the key factors for the deactivation of S-poisoned samples. However, surface-active oxygen and NO adsorption are increased by NH4HSO4 deposition, and the L–H mechanism is promoted over S-poisoned samples. Due to the interaction between V, Ce and Cu, the surface-active oxygen over VWCeCuTi-S is increased, and then NO adsorption is promoted. In addition, VWCeCuTi-S obtains a higher V5+ ratio and a better redox property than VWTi-S, which in turn accelerates the NH3-SCR reaction. More NO adsorption and encouraged reaction contribute to the better sulfur resistance of VWCeCuTi.

In this study, the deactivation of commercial V2O5-WO3/TiO2 selective catalytic reduction catalysts by Pb was discussed primarily, and the combined promotive effects of SO2 and HCl on Pb-poisoned V2O5-WO3/TiO2 catalysts were studied. The results show that the treatment with SO2 and HCl markedly improves the NOx conversion of Pb-poisoned catalysts. SO2 and HCl react with Pb chemisorbed on V2O5, which increases effectively the ratio of V5+ and active oxygen species and the amount of acid sites.