CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Jiangtao Meng,Jing Wang,Fengling Yang,Fangqin Cheng
This study proposed a novel strategy to control nitrogen oxides (NOx) precursors by directing nitrogen to adhere to the fuel-N→NH 3 →N 2 pathway. The research aimed to illuminate the regulatory effects of CaO, Fe 2 O 3 , and their mixtures on NO and N 2 O precursors (NH 3 , HCN, and HNCO) during sludge pyrolysis, further sought to establish scientific correlations with varying temperatures and differentiate their impact. The findings indicated that unlike NH 3 , HNCO is generated from the cleavage of amides, sharing its origin with HCN. Notably, the sensitivities of three conditioners to different functional groups result in distinct impacts on precursor emissions. CaO interacted with –OH and N-H functional groups, releasing NH 3 . Fe 2 O 3 , being more responsive to C-H and C-C groups, contributed to HNCO emission. At 750 °C, a CaO-Fe 2 O 3 mixture created Ca x Fe y O z , which selectively reacted with N-H and C≡N, facilitating the conversion of HNCO and HCN to NH 3 . While temperature is a crucial factor in the performance of CaO, its impact on Fe 2 O 3 is primarily confined to transformation of heterocyclic and nitrile . Below 350 °C, Fe 2 O 3 favored the evolution of nitrogen into heterocyclic compounds within tar. Conversely, above 490 °C, it inhibited the formation of nitrile in char, promoting the dehydrogenation of tar into unsaturated aromatic structures. The CaO-Fe 2 O 3 mixtures exhibited a superposition of individual effects from CaO and Fe 2 O 3 , with Ca x Fe y O z stimulating N 2 emission. Importantly, among three conditioners, Fe 2 O 3 showed the most significant abatement effect on NOx precursors, primarily through nitrogen fixation in char, nitrogen enrichment in tar, and precursor oxidation. This research contributes innovative perspectives on nitrogen regulation in nitrogen-rich fuels, the utilization of NH 3 , and effective NO and N 2 O control.
研究领域:
环境科学
·
能源工程
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产品关联
DOI
高影响因子
Thermal Science and Engineering Progress
·
2023
·
IF 4.8
Shuai Guo,Guoliang Qi,Jialiang Gao,Deng Zhao,Kaixin Chen,Chenchen Zhao,Xingcan Li,Guangyu Li
Pyrolysis is an effective method for safely disposing of sewage sludge via conversion into a usable energy source. However, municipal sludge has a high protein content, which is a major source of NO x precursors. This study investigated the effect of CaO on NO x precursor formation during glutamate pyrolysis and demonstrated that CaO occupies the carbo x yl site of glutamic acid at 320 °C, which delays its decomposition and promotes the conversion of glutamic acid from a five- to a si x -membered ring. At 400 °C, heterocyclic nitrogen in the tar peaked from 4.87 to 53.87% after adding CaO. As the temperature increases to 480 °C, CaO might promote the conversion of heterocyclic nitrogen into tricyclic piperazine dione in the tar, which subsequently decomposed to produce HCN in large quantities. At 480 °C, CaO contributed to the decrease in pyrrole, pyridine, and quaternary nitrogen in the semi-coke from 24.81%, 12.93%, and 7.43% to 1.91%, 5.97%, and 1.43%, respectively and promoted HCN hydrolysis to form NH 3 . At 480–680 °C, CaO interacted with NH 3 to form CaCN 2 . The product of CaC x N y decomposition—CaC x —captured NH 3 . At high temperatures, CaO inhibited HCN release, which might be related to the reaction between CaO and HCN to form CaC x N y , subsequently reconverted into CaO at temperatures above 680 °C. These findings provide novel insights into the influence of CaO on amino acid pyrolysis to produce NO x precursors and the regulation of NO x precursor production.
研究领域:
环境科学
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能源与燃料
✓ 已验证
产品关联
DOI
高影响因子
Chem Catalysis
·
2022
·
IF 0
Xianhao Zhang,Huijuan Jing,Shiming Chen,Bing Liu,Liang Yu,Jianping Xiao,Dehui Deng
Summary Cyclohexanone oxime (CHO), a key C=N organic compound in the manufacture of nylon 6, is conventionally synthesized via a multistep process that consumes expensive NH 3 and H 2 under harsh conditions. Herein, we report the direct electro-synthesis of CHO from low-cost NO, H 2 O, and cyclohexanone over a carbon catalyst under ambient conditions. A high Faradaic efficiency of 44.8% and a formation rate of 10.7 mg cm −2 h −1 for CHO were achieved at −0.4 V versus the reversible hydrogen electrode through optimizing the surface hydrophobicity of the catalyst to facilitate diffusion of reactants. Controlled experiments and 15 N-labeling tests verified that the nitrogen in the CHO product originates from NO. Density functional theory calculations showed that the armchair edge of carbon could be the active site with a reaction mechanism following NO → NO∗ → HNO∗ → HNOH∗ → NH 2 OH → CHO. This work suggests a direct, green, and low-cost synthesis strategy for high-value CHO from pollutant NO.
研究领域:
化学工程
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环境科学
✓ 已验证
DOI
ENERGY & FUELS
·
2017
·
IF 3.091
Linlin Yi,Huan Liu,Geng Lu,Qiang Zhang,Jiaxing Wang,Hongyun Hu,Hong Yao
Considerable amounts of NOx are generated from the thermal utilization of solid wastes. To control NOx emission, we investigated the influence of mixed Fe/Ca additives on the generation of NOx precursors (HCN and NH3) during pyrolysis at 873, 1073, and 1273 K. Protein, proline, and phenylalanine were selected as model compounds to represent the primary nitrogen forms in typical solid wastes, such as biomass and sludge. According to the results, the iron effect is a remarkable property that enables the obvious reduction of NH3. This was most likely because NH3 was consumed by iron compounds to generate FeNx. Iron compounds facilitated thermal cracking of heterocyclic N with the release of HCN. Ca(OH)2 promoted the conversion of HCN to NH3 and fixed HCN to form CaCxNy simultaneously. These intermediates (FeNx and CaCxNy) play important roles in the reduction of NOx precursors. A lower emission of NOx precursors was observed with mixed Fe/Ca additives than with either Fe or Ca individually. This is because the generation of Ca2Fe2O5 enhanced the tranformation of intermediates to N2. The transformation of intermediates to N2 was enhanced at elevated temperatures, which allows for the lowest emission of precursors (NH3 and HCN) at 1273 K, with a higher ratio of Ca2Fe2O5 in char.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Shaolong Yang,Zhitao Han,Xinxiang Pan,Bojun Liu,Dongsheng Zhao
UV/chlorine has attracted much attention in flue gas and water treatment fields in recent years. However, only a few studies highlighted gas pollutants removal performance of UV/chlorine method in real water. In this study, nitrogen oxide (NO x ) removal using UV-irradiated electrolyzed seawater (UV/electrolyzed seawater) was explored under simulated seawater environment in a semi-batch photochemical reactor. Comparison experiments between UV/H 2 O 2 and UV/chlorine in both freshwater and seawater systems were performed. Results showed that NO removal efficiency in UV/chlorine freshwater system was higher than those in UV/chlorine seawater system, due to radical scavenging effects of water matrices in seawater. Several strong reactive radicals (e.g., OH, Cl, OCl, ClOH − ) yielded from UV/chlorine system were considered to contribute to NO x removal, among which the role of OH radical was confirmed by radical-trapping experiments. The alkalinity of the seawater adversely impacted contributions of these reactive radicals to NO x removal, which caused a sharp drop in NO x removal efficiencies. Comparatively, the chloride ion in seawater had slight influences on NO x removal efficiencies of UV/electrolyzed seawater. Then, optimization of NO x removal efficiencies against three key variables (active chlorine concentration, UV irradiation dose, and initial pH) was investigated in simulated seawater using Design Expert Software. A regression model of NO x removal efficiency was obtained with satisfactory accuracy. Results indicated that active chlorine concentration and UV irradiation dose significantly influenced NO x removal efficiencies, compared with pH effects. Furthermore, NO x removal mechanisms involved in reactive radicals were discussed for UV/electrolyzed seawater method. Due to pH-dependent characteristics of both active chlorine species and carbonate species in electrolyzed seawater, NO x removal pathways by UV/electrolyzed seawater were different as the environment changed from acid to alkalinity.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Xuanhao Liang,Guangyuan Chen,Hao Zhang,Ling Zhang,Tao Duan,Lin Zhu
Ti-based MOFs exhibit ultra-high stability in radioactive waste gases containing nitrogen oxides (NO X ) and are effective in capturing radioactive iodine. In this study, NH 2 -MIL-125 was synthesized via a one-pot solvothermal method and its adsorption performance for iodine was investigated using batch adsorption experiments, the stability of materials was tested by simulating post-processing conditions. The results indicated that NH 2 -MIL-125 had a maximum iodine adsorption capacity of 1.61 g/g at 75 ℃ and reached adsorption equilibrium within 60 min, and the adsorption capacity of methyl iodine reached 776.9 mg/g. The material also exhibited excellent stability and iodine adsorption performance in the presence of NO X . After soaking in NO 2 for 24 h, its structure remained stable and the adsorption capacity for iodine remained at 231.5 mg/g. The excellent co-adsorption performance of NH 2 -MIL-125 on iodine and NO X was attributed to the synergistic effects of Ti-OH groups and amino functional groups. These findings provide a reference for the capture of radioactive iodine and also demonstrate the potential of NH 2 -MIL-125 for iodine capture during spent fuel reprocessing .
研究领域:
材料科学
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环境科学
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核能工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Senlin Tian,Shanshan Yang,Jianfei Wang,Qiuxian Li,Chen Li,Xiangfen Cui,Ping Ning
Nitrogen and sulfur oxides have been considered as major air pollutants , which has raised concerns. In this study, an integrated strategy is proposed for simultaneous desulfurization and denitrification of simulated flue gas and high value conversion of sulfur and nitrogen resources. The high oxidation capacity of the thermal-electric coactivated (NH 4 ) 2 S 2 O 8 made the process highly effective for SO 2 and NO removal, with efficiencies of 100 % and 98 %, respectively. Mechanistic studies have revealed that highly reactive free radicals were the major participants in promoting oxidation, among which 47.65 % and 27.75 % of NO were oxidized by SO 4 .- and ˙OH, respectively, and 14.3 % and 10.3 % removal were accounted for O 2 .- and 1 O 2 , respectively. The products of desulfurization and denitrification (SO 4 2- and NO 3 - ) were further converted into NH 4 + (maximum conversion efficiency of 83.80 %) and S 2 O 8 2- (maximum conversion efficiency of 70 %) in an electrolytic reactor, and the regenerated (NH 4 ) 2 S 2 O 8 could be recycled for gas purification to extend the service life of the oxidant. Consequently, a complete conversion cycle of S and N species was obtained, and its conversion pathways were proposed. After several cycles, the SO 4 2- and NO 3 - enriched in the solution were post-processed into a compound fertilizer, thereby partially recovering the economic cost.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
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2014
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IF 3.828
Huan Liu,Qiang Zhang,Hongyun Hu,Peng Liu,Xiaowei Hu,Aijun Li,Hong Yao
Thermal disposal of sewage sludge is likely to cause serious nitrogen related environmental pollution since it contains considerable amounts of nitrogen, the species of which are quite different from those in coal. Considering that lime (CaO) is a widely applied chemical conditioner for sewage sludge dewatering, this study investigated the catalytic role of conditioner CaO in nitrogen transformation during sewage sludge pyrolysis in a drop-tube/fixed-bed furnace at 873 K, 1073 K and 1273 K, respectively. Model compounds were also used to further clarify the mechanisms involved. According to the results, conditioner CaO increased the fraction of more stable protein-N as well as amine-N. The solid phase reactions produced CaC x N y , thus enhancing the nitrogen retention in char. Correspondingly, decreased relative ratio of nitrates-N/nitrites-N and oxygenated organics in sludge conditioning contributed to less NO emission. Meanwhile, conditioner CaO promoted the conversion of HCN to NH 3 , as well as the deamination of proteins, amine, and other N-containing compounds in tar and char, leading to increased NH 3 generation. Subsequently, CaC x , the decomposition product of CaC x N y , captured NH 3 , driving down the final production of NH 3 . In addition, Ca(OH) 2 hindered the transformation of nitrile-N in char to HCN, decreasing HCN generation. CaO reacted with HCN, further reducing its releasing amount. CaC x N y derived from different sources decomposed to produce a very large amount of N 2 . These indicate that reusing conditioner CaO is a promising strategy for reducing the productions of NO x precursors efficiently and increasing the formation of non-polluting N 2 dramatically.
研究领域:
环境科学
·
能源与燃料
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Yin Tang,Wen Cui,Songxia Wang,Yan Li,Jiaqi Wang
Photocatalytic technology has emerged as a promising solution for air purification of ppb-level nitrogen oxides (NO x ), but potential risk of secondary pollution should not be overlooked, which could be triggered by the production of toxic intermediate and the potential release of airborne catalyst particles during reaction processes. Herein, nickel foam (NF) has been introduced as not only carrier material but also performance promoter for zinc oxide (ZnO). The NF supported ZnO sample (Ni-ZnO/NF) demonstrates multifunctional superiority: 66.4 % nitric oxide (NO) removal efficiency, <1.7 % nitrogen dioxide (NO 2 ) byproduct generation, and ultralow photocatalyst loss (<1.2 % mass). Mechanistic investigations combining experimental characterization and theoretical simulations reveal atomic substitution processes where NF-derived Ni atoms replace Zn sites in the ZnO lattice, forming stable Ni-O interfacial bonds, which contributes to enhance interaction between ZnO and NF for firm immobilization and form electron localization zones around Ni-O bond for reactants activation and reactive oxygen species formation. The optimized reaction pathway (NO + e − → NO − , NO − + 1 O 2 → NO 3 − ) ensures complete oxidation while suppressing hazardous intermediates. This work blueprints next-generation supported photocatalysts through atomic-level interface engineering, advancing practical application of photocatalytic technology for sustainable air purification.
研究领域:
环境科学
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
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2025
·
IF 7.3
Bowen Duan,Senchao Lai,Qiaoze Zhu,Zhiwei Pan,Yingyi Zhang
Proteins in aerosols can undergo multiphase reactions when exposed to air pollutants like ozone (O 3 ) and nitrogen dioxide (NO 2 ), posing adverse impacts on the environment and human health. The influence of radiation on the reactions has not been thoroughly studied and the reaction mechanism remains unclear. We coated bovine serum albumin exposed (BSA) in a flow tube and exposed it to different combinations of O 3 and NO 2 under dark and ultraviolet (UV) radiation conditions. The results showed that O 3 could significantly promote the degradation, nitration and oligomerization of BSA, indicating that O 3 is the primary driver of the multiphase reactions. We found that UV enhanced protein degradation after exposure to NO 2 and O 3 . Meanwhile, UV also enhanced the nitration and oligomerization of protein by NO 2 . When exposed to NO 2 and O 3 , the effects of nitration and oligomerization on tyrosine residue of BSA was also investigated. Nitrated tyrosine (NTyr) levels were always higher than that of cross-linked tyrosine (DiTyr), highlighting the dominance of nitration in modification reactions. However, the negative influence of UV radiation on protein nitration and oligomerization of BSA was observed in our exposure experiment. We propose that UV radiation induced degradation may be an important factor to suppress nitration and oligomerization via the breakage of nitrated and oligomerized protein products. This work provides the dataset and knowledge by laboratory exposure to emphasize the possible role of radiation in the multiphase reactions of proteins in the atmosphere, which will help to gain a better understanding of reaction mechanisms.
研究领域:
环境科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
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IF 4.939
Shaolong Yang,Jinxin An,Xianbo Xiang,Zhitao Han,Xinxiang Pan
Seawater electrolysis is an attractive way to generate hydrogen energy . However, to commercialize this technology, it has been focused on developing chlorine-less oxygen generating electrodes for decades. Here, different from common ideas of minimizing chlorine formation at the anode, we aimed at reusing the waste chlorine from seawater electrolysis to mitigate nitrogen oxide (NOx) emissions. NOx removal performance of electrolyzed seawater containing chlorine was investigated under 254 nm ultraviolet (UV) irradiation in a semi-continuous bubbling reactor. Comparative parametric experiments were conducted for each factor with and without UV irradiation. Significant contributions of UV irradiation on denitrification performance of chlorine were observed under all investigated conditions. A ten-folder improvement in denitrification efficiency by the UV irradiated electrolyzed seawater was achieved under optimal conditions. Possible free radicals’ reaction mechanisms were discussed preliminarily. Results reveal that UV irradiated electrolyzed seawater is a promising way to reuse electrolyzed chlorine and mitigate acid gas emissions.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 102
·期 10
·6194-6201
·
IF 3.094
Shunhang Wei,Shu Jin,Guoxiang Pan,Zuxin Li,Gang Liu,Xiaoxiang Xu
Although BaNbO 2 N has visible light absorption as far as 740 nm, its photocatalytic activity is generally very poor under ordinary conditions, being incommensurate to its light absorption properties. In this work, we introduce Ca into the B site of BaNbO 2 N to form a complex perovskite BaNb 1− x /3 Ca x /3 O 2+ y N 1− y (0 ≤ x , y ≤ 1). The presence of Ca in BaNbO 2 N has great impact on a number of important properties such as band gap value, nitrogen content, surface hydrophilicity, and defects levels. In particular, defects such as Nb 4+ species are effectively suppressed in Ca-modified BaNbO 2 N. More importantly, photocatalytic activity of BaNbO 2 N for water oxidation reactions is substantially improved after Ca modifications. Compared with pristine BaNbO 2 N, more than twofold enhancement in photocatalytic oxygen evolution is observed for BaNb 0.8 Ca 0.2 O 2+ y N 1− y ( x = 0.6). Such improvements probably stem from the suppression of Nb 4+ species in the structure as well as enhanced surface hydrophilicity after Ca modification. The facile approach by incorporating alkaline earth cations into crystal structure can be well extended to other perovskite oxynitrides whose photocatalytic activity is subject to those defective species.
研究领域:
材料科学
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光催化化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）