ENERGY & FUELS
·
2020
·
IF 3.421
Jie Yu,Esong Zhang,Lele Wang,Zijian Song,Fanhai Kong,Yunlong Ma,Hong Zhao,Lushi Sun
With the wide application of selective catalytic reduction (SCR) systems in power plants for the control of NOx emission in China, a serious problem of catalyst deactivation due to the channel blockage by NH4HSO4 has drawn extensive attention. In this work, a combined experimental and simulation method was utilized to study the interaction between NH4HSO4 and a vanadium–titanium-based catalyst. Initially, the adsorption characteristics of NH4HSO4 onto TiO2, V2O5/TiO2, V2O5-WO3/TiO2, and V2O5-MoO3/TiO2 were simulated following density functional theory. The simulation revealed that during reaction, the NH4HSO4 loaded onto TiO2 can be dissociated into NH4+ and SO42–. The existence of V2O5, WO3, and MoO3 can form a protective layer to inhibit the adsorption of NH4HSO4 onto TiO2, to promote the reduction of sulfur-containing compounds, and to accelerate the reaction of NH4+ with NO. Thermogravimetric analysis also showed the positive effect of V, W, and Mo on NH4HSO4 decomposition. Fixed-bed experiments were then conducted to compare the performance of the studied catalysts and the effect of NH4HSO4 on their performance. It was proven that the V-5Mo/TiO2 catalyst showed better performance at low temperatures. On the V-5Mo/TiO2 catalyst, ∼78 wt % NH4+ in NH4HSO4 was attached onto Lewis acid sites, which can accelerate the reduction reaction of NO by NH4+. Meanwhile, SO42– can comparatively be easily decomposed at lower temperatures.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Yuefei Ji,Yuanyuan Shi,Lu Wang,Junhe Lu
Nitrobenzene (NB) is a recalcitrant organic compound caused great environmental concerns. Sulfate radical-based advanced oxidation processes (SR-AOPs) are promising environmental remediation and wastewater treatment technologies. In this contribution, we observed that degradation of NB by thermally activated persulfate oxidation process resulted in the formation of a suite of intermediates including 2-nitrophenol (2-NP), 3-nitrophenol (3-NP), 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), 2,6-dinitrophenol (2,6-DNP), and 2,4,6-trinitrophenol (2,4,6-TNP) as well as coupling products. The formation of the nitrophenols was suggested to follow the sequence of mononitrophenols → dinitrophenols → trinitrophenol. Time-dependent evolutions of mononitrophenols and dinitrophenols were illustrated and their formation mechanisms were proposed. The evolution patterns of mononitrophenols were fitted by sequential reaction kinetic model. The formation of polynitrated phenolic compounds suggests that both denitration and nitration processes occurred during SO 4 − -based oxidation of NB. Nitration agent (i.e., NO 2 ) arising from the conversion of nitro group upon SO 4 − /HO attack is proposed to play an important role in the formation of polynitrated compounds. TOC measurement revealed that mineralization was less efficient as compared with NB degradation. The presence of NO 2 − was found to inhibit the degradation of NB but promote the formation of 2,4-DNP. Temperature played an important role in both the degradation of NB and the distribution of products. Since polynitrated aromatics are more persistent and mutagenic, the results of this contribution suggest that particular attention should be paid to their formation during SO 4 − -based oxidation processes.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Zhifei Hao,Guoquan Liu,Nan Ma,He Zhang,Yi Li,Yuguo Xia,Dongpeng Zhang,Sihui Zhan
Acidity and redox properties of the catalyst are two crucial factors affecting the performance of NH 3 -SCR. Herein, we design a novel WO x /Cu-CeO 2 oxide catalyst in which the WO x species are highly dispersed on the {111}/{100}-terminated surface of Cu-doped CeO 2 nanospheres , which exhibits great deNO x activity advantage and wide operating temperature window (200–400 °C, over 85% NO x conversion with a gas hourly space velocity (GHSV) of 60,000 h −1 ), as well as good sulfur resistance and N 2 selectivity . The relationship among the composition, acidity and redox properties of the WO x /Cu-CeO 2 catalyst is established in the NH 3 -SCR reaction. The combined experimental studies and spectroscopic characterization reveal that the introduction of Cu into the lattice of CeO 2 not only increases the surface Ce 3+ and oxygen vacancy concentration but also provides more sites for capture and dispersion of WO x species, thus mediating and improving the Lewis and Brønsted acid sites and reducibility of catalyst. XPS and DFT calculations further demonstrate that electronic interaction between WO x and Cu-doped CeO 2 is enhanced duo to the existence of interactions of short-range Ce-O-Cu and Ce-O-W. Moreover, the NH 3 -SCR reaction over WO x /Cu-CeO 2 may follow both Langmuir-Hinshelwood and Eley-Rideal reaction pathway according to the in situ DRIFTS.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 84
·53622-53630
·
IF 3.108
Changming Li,Hong Zeng,Pingle Liu,Jian Yu,Feng Guo,Guangwen Xu,Zhan-guo Zhang
The development of new routes for the utilization of red mud (RM) waste is very urgent due to its huge accumulation and potential environmental harm. By taking advantage of its Fe–Al–Si–Ti composition and excellent plasticity, we developed a ball milling and acid–base neutralization method to reuse the RM waste as Fe-based denitration catalysts. The resulting RM catalysts demonstrate excellent catalytic activity and stability with >90% NO conversion above 400 °C in the presence of SO2 and H2O, which is even much better than that of a commercial V–W–Ti catalyst. Characterization data reveal that our treatment eliminates poisonous alkaline metal elements and increases dispersion of RM particles, making the RM active for denitration reactions. The formation of ferric sulfate species with more reducible Fe3+/Fe2+ active sites by a SO2 activation method can further enhance the denitration activity. Moreover, NH3-TPD and in situ IR results demonstrate that the NH3-SCR reaction over the RM catalyst follows the Eley–Rideal mechanism at high temperature and the increased absorption of NH3 for alkaline metal-eliminated or SO2-activated samples accounts for its high DeNOx efficiency. The demonstrated feasibility for reusage of the RM as DeNOx catalyst has promising industrial prospects for its extremely low cost, no toxicity, and high efficiency.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
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
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2019
·
IF 7.149
Fei Wang,Zhibo Xie,Jinsheng Liang,Baizeng Fang,Yu’ang Piao,Ming Hao,Zishuo Wang
Low temperature NH3 selective catalytic reduction (NH3-SCR) technology is an efficient and economical strategy for cutting NOx emissions from power-generating equipment. In this study, a novel and highly efficient NH3-SCR catalyst, tourmaline-modified FeMnTiOx is presented, which was synthesized by a simple one-step sol–gel method. We found that the amount of tourmaline has an important impact on the catalytic performance of the modified FeMnTiOx-based catalysts, and the NOx conversion exceeded 80% from 160 to 380 °C with the addition of 5 wt % tourmaline. Compared with the pure FeMnTiOx, the catalytic efficiency at a temperature below 100 °C was increased by nearly 18.9%, and the operation temperature window was broadened significantly. The enhanced catalytic performance of the FeMnTiOx catalyst was mainly attributed to the small spherical nanoparticles structure around the tourmaline powders, resulting in the increased content of Mn3+, Mn4+, and chemical oxygen on the catalytic surface. These as-developed tourmaline-modified FeMnTiOx materials have been demonstrated to be promising as a new type highly efficient low temperature NH3-SCR catalyst.
研究领域:
环境科学
·
催化材料
·
能源工程
✓ 已验证
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jiangxiao Qiao,Jinxin Gan,Fei Gao,Xiangsen Xu,Jiesong Tan,Yiqing Zeng,Feng Zhang,Feng Han,Zhaoxiang Zhong,Weihong Xing
Synergistic removal of nitrogen oxides (NOx) and particulate matter (PM) can be achieved using multifunctional catalytic membranes. In this work, CePO4 nanorods were loaded on the pore surfaces of SiC membranes to construct the CePO4/SiC-X catalytic membranes. The stacked nanorod structure of the CePO4 catalyst layer facilitates the diffusion of gases to the catalyst surface during reactions. Owing to the high specific surface area, rich surface acidity, and strong redox capacity, the CePO4/SiC-400 catalytic membrane exhibits the best ammonia-selective catalytic reduction (NH3–SCR) denitration activity, achieving >90% NO conversion at a temperature of 250–380 °C and negligible N2O byproduct. In addition, the CePO4/SiC-400 catalytic membrane demonstrates excellent H2O and SO2 resistance. The performance of dust filtration and simultaneous dust filtration and denitration at 250–350 °C proposed that the dust rejection efficiency reached more than 99% at various conditions, and the dust filtration process did not affect the NH3–SCR performance of the CePO4/SiC-400 catalytic membrane. From the above results, the CePO4/SiC-400 catalytic membrane presents a broad application prospect in the simultaneous dust removal and denitration of high-temperature flue gas.
研究领域:
环境科学
·
催化材料
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2016
·
IF 1.207
Jie Wang,Wenqi Zhong
Experiments on simultaneous absorption of SO 2 and NO X from sintering flue gas via a composite absorbent NaClO 2 /NaClO were carried out. The effects of various operating parameters such as NaClO 2 concentration ( m s ), NaClO concentration ( m p ), molar ratio of NaClO 2 /NaClO ( M ), solution temperature ( T R ), initial solution pH, gas flow ( V g ) and inlet concentration of SO 2 ( C S ) and NO ( C N ) on the removal efficiencies of SO 2 and NO were discussed. The optimal experimental conditions were determined to be initial solution pH = 6, T R = 55 °C and M = 1.3 under which the average efficiencies of desulfurization and denitrification could reach 99.7% and 90.8%, respectively. Moreover, according to the analysis of reaction products, it was found that adding NaClO to NaClO 2 aqueous solution is favorable for the generation of ClO 2 and Cl 2 which have significant effect on desulfurization and denitrification. Finally, engineering experiments were performed and obtained good results demonstrating that this method is practicable and promising.
研究领域:
环境工程
·
化学工程
·
能源技术
·
污染控制
·
工业生态学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Feng Xiaoxin,Zhou Tingting,Liu Zhigang,Yang Lirong,Wang Chunmei,Xie Yuantao,Li Qinglong
Iron oxide red (IOR) is a kind of byproduct from spray pyrolysis treatment process of pickling waste liquid. In this project, manganese oxide and manganese cerium co-oxide were loaded onto the surface of IORto prepare IOR supported manganese oxide (Mn x /IOR) and IOR supported manganese-cerium co-oxide (Mnx-Cey/IOR) catalysts by a simple combustion method. Low temperature NH3-selective catalytic reduction (NH3-SCR) denitrification properties of the synthetic catalysts were studied. XRD , SEM, EDS , TEM, BET, XPS, H 2 -TPR and NH 3 -TPD were used to characterize the physiochemical properties of the catalysts. The results show that during the combustion process for preparing Mnx/IOR catalyst, MnO x , almost all in amorphous phase, can be well distributed on the surface of the IOR carrier. The NO x conversions of Mn x /IOR catalyst gradually increase with the increase of MnO x loading amount within a specific working temperature range (<200 °C). When MnO x loading amount x is 0.43, the NO x conversion is up to 85% at most. The low temperature NH 3 -SCR activity of Mn x /IOR catalyst can be enhanced remarkably by introducing cerium . The NO x conversions of Mn 0.43 -Ce y /IOR catalyst at the operating temperature range (<200 °C) increase steadily with the cerium adding amount increasing. All the Mn 0.43 -Ce y /IOR catalysts show excellent denitrification efficiency (more than 90%) at about 160 °C. Compared with Mn 0.43 /IOR catalyst, Mn 0.43 -Ce 0.1 /IOR shows excellent denitrification performance and application prospect because of its higher manganese valence state, enhanced redox capacity, larger specific surface area, and significantly improved surface acidity and anti-SO 2 poisoning ability.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
·
2017
·
IF 4.364
Zijian Su,Yuanbo Zhang,Benlai Han,Bingbing Liu,Manman Lu,Zhiwei Peng,Guanghui Li,Tao Jiang
Chemical vapor transport (CVT) process is a simple and efficient method for synthesizing nano-SnO products, and previous references reveal that the CVT process is characterized as high temperature and long synthesis time. Our previous studies indicated that SnO 2 was easily reduced to solid-state SnO and then volatilized as gaseous SnO under certain CO-CO 2 atmosphere, so that a novel CVT process under CO-CO 2 atmosphere was proposed in the present work. The nano-SnOs synthesized by the CVT under 15 vol% CO/(CO + CO 2 ) atmosphere were characterized using XRD , SEM, TEM, XPS , etc. The results showed that tetragonal structure nano-SnO diskette and sphere with uniform granularity of 50–100 nm were obtained with high purity. During the CVT process, CO-CO 2 mixed gases could reduce SnO 2 to SnO and act as a CVT medium to take away the newly formed gaseous SnO, resulting in the decrease of the partial pressure of SnO. In addition, the nano-SnOs could enhance the SCR deNOx activity of activated carbon (AC), and both the reaction temperature window of AC and the NO conversion were increased if the AC was coated by nano-SnOs.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Junxiong Zhao,Yan Yang,Chuang Lei,Shengchao Xu,Hao Lin,Qifeng Wei,Xiulian Ren
The use of two-phase absorbents containing amides to treat ship pollutants is a new research solution that can achieve high NO oxidation rates and NO 2 absorption rates. This paper studies the physicochemical properties of five different amides and their relationship with the desulfurization and denitrification processes. It was found that nitrous acid molecules undergo an isomerization rearrangement in the amide and combine in a more stable form during the NOx absorption process. The polarity and viscosity of the amide are more critical than the min ESP value in removing pollutants. The high polarity and low viscosity of DBA (N,N-Dibutylacetamide) provide dual advantages, facilitating the interaction between the organic and aqueous phases, as well as enhancing the mass transfer process and the combination of an inorganic acid. The system containing DBA achieved removal efficiencies of 99.6% for SO 2 , 86.33% for NO, and 86.3% for NOx in 10 min. Overall, this study provides valuable insights into the use of organic-containing two-phase absorbents to reducing ship exhaust pollution.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Mingjia Zhang,Shule Zhang,Fanyu Meng,Mengjie Hu,Zhongyu Wang,Yiqing Zeng,Qin Zhong
Promoting the formation of Ti-OOH in the TiO 2 -based-catalyst/H 2 O 2 /O 3 system is critical to further develop the catalytic peroxone process for low-temperature flue gas denitration. In this study, a series of phosphorus-doped TiO 2 with rich Lewis acid sites and high stability was designed and established, achieving 94 % NO oxidation efficiency with less oxidant (373 K, H 2 O 2 /NO = 1.2, O 3 /NO = 0.5) and high GHSV (1.2 × 10 5 h −1 ). Combining characterizations and DFT results, a possible mechanism was proposed: phosphorus-doping enhanced the Lewis acidity, which was conducive to the adsorption and activation of H 2 O 2 . Moreover, P-TiO 2 significantly promoted the H 2 O dissociation and Ti-OOH formation process by reducing the energy barrier, thereby promoting the synergistic effect between O 3 and Ti-OOH. The semi-in-situ UV–vis DRS demonstrated that the catalytic peroxone process occurs at the solid–liquid interface and the Ti-OOH is consumed in the catalytic process. We hope this work provide a new investigation method and insight into the catalyst design.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）