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
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2020
·Vol. 27
·期 24
·30243-30253
·
IF 3.056
Xu Wenqing,Gao Lei,Yang Yang,Zhu Tingyu,Qi Guisheng
The deposition of NH 4 HSO 4 on catalysts is one of the key issues for selective catalytic reduction of NO x . In this study, NH 4 HSO 4 was preloaded on catalysts, and the effects of MoO 3 and CeO 2 doping on the decomposition and reactivity of NH 4 HSO 4 on V 2 O 5 /TiO 2 catalysts are studied. The results show that the introduction of MoO 3 and CeO 2 significantly promoted NO x conversion on the V 2 O 5 /TiO 2 catalysts. Doping with MoO 3 could effectively enhance the S and H 2 O resistance of the catalysts. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicate that it is the strong chemical interactions between NH 4 HSO 4 and the catalysts that are adverse to the decomposition of NH 4 HSO 4 . However, doping with MoO 3 apparently inhibits these interactions, which significantly decrease the decomposition temperature of NH 4 HSO 4 . In situ FTIR experiments show that the NH 4 + in preloaded NH 4 HSO 4 could react with gaseous NO on catalysts, and doping with MoO 3 could facilitate the reaction rate.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
Materials Research Express
·
2022
·Vol. 9
·期 6
·065504
·
IF 2.025
Xin Lin,Chaoyi Chen,Junqi Li,Gangan Wang,Deyang Ning
Brown corundum dust ash(BCFA) is an industrial solid waste from the brown corundum production process. The alkali metal is a key factor limiting its comprehensive use. Currently, BCFA is mainly stockpiled and occupies a large amount of land. Its fine particles are easy to cause air pollution. The addition of NH4HSO4 allows for the effective extraction of K from BCFA and the efficient use of BCFA. Under optimum conditions: NH4HSO4 to BCFA mass ratio of 1.2:1, the roasting temperature of 240 °C, roasting time of 2 h, water leaching time of 90 min, water leaching temperature of 65 °C water leaching liquid to solid ratio of 3:1, the leaching rate of K from BCFA reached 97%. The leachate was crystallised by evaporation to obtain K, N compound fertiliser for agricultural use. The leaching residue is mainly Al and Si, which can be used for the preparation of refractory materials, aluminium and silicon molecular sieves, construction materials and other raw materials.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Ao Zhou,Dan Zhang,Zhihong Liu,Zhiyong Liu
With the retirement of rechargeable lithium-ion batteries (LIBs) entering peak period, the recycling of LiCoO 2 has become a hot topic. The spent LiCoO 2 batteries are rich in carcinogenic metal Co and high-value metal Li, so they are needed to be recovered in time before causing serious environmental pollution and resource waste. Thus, a clean and efficient process is proposed for the comprehensive recovery of Li, Co, and Mn from the spent LiCoO 2 cathode material. It is an integrated pyro-hydrometallurgical process, mainly consisting of sulfation roasting with NH 4 HSO 4 and selective sulfurizing leaching with (NH 4 ) 2 S solution. Using low melting point ammonium salt as roasting auxiliary, 99.7 %, 99.1 %, and 99.8 % of Li, Co, and Mn in the spent LiCoO 2 powder can be converted into sulfate when roasting under 400 ℃ for 75 min. Then 99.5 % of Li in the sulfation roasting product can be selectively leached with an aqueous (NH 4 ) 2 S solution, which is also a precipitator for Co, Mn, and impurity Al. In addition, 96.4 % of Co and 96.0 % of Mn in the sulfurized precipitate can be separated with impurity elements Al and C via oxidation roasting–water leaching process. Compared to traditional recycling, this method can achieve a higher Li leaching rate at a low roasting temperature, and the recovery of Co and Mn can be realized without adding any acid/base reagents or impurity cations. More importantly, the circulation of NH 3 /NH 4 + and S element in the recycling system has been taken into account, making it an environmental-friendly and economical process. In this study, the sulfation reduction roasting and selective sulfurizing leaching mechanisms were both revealed in details, and the behavior of the valuable elements was also elucidated.
研究领域:
环境科学
·
冶金工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2025
·
IF 2.4
Huimin Li,Yucheng Lin,Liutao Hou,Yuli Wang,Huijuan Tian,Shiqiang Zhao,Chun Chang
BACKGROUND 5-Hydroxymethylfurfural (HMF), as an important biomass platform compound, can be transformed into biofuels and numerous high value-added chemicals, and occupies an extremely important position in biorefining. Herein, a novel catalytic system has been developed for the direct conversion of glucose to HMF using inexpensive Na 2 SO 4 /NH 4 HSO 4 as the catalyst. RESULTS The maximum glucose conversion of 90.77% with 45.05% yield of HMF was obtained at 190 °C, catalyst Na 2 SO 4 /NH 4 HSO 4 80 wt%, water and methyl isobutyl ketone volume ratio 1/5, and residence time 20 min. A kinetics model was developed to predict the yield of HMF and glucose conversion, which was consistent with the experimental results. CONCLUSION The continuous production of HMF from glucose can be efficiently performed with Na 2 SO 4 /NH 4 HSO 4 with a mass ratio of 3/2 as the catalyst. This catalytic system for the continuous production of HMF has great practical significance and potential economic value for promoting the industrial production of HMF and its derivatives. © 2025 Society of Chemical Industry.
研究领域:
生物质转化
·
催化化学
·
化工工艺
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Ao Zhou,Zhihong Liu,Zhiyong Liu
With the imminent peak in the retirement of rechargeable lithium-ion batteries worldwide, the development of efficient methods for recycling valuable elements from LIBs has attracted considerable attention. In this work, a novel method of NH 4 HSO 4 reduction roasting-selective ammonia leaching was proposed to thoroughly separate Li and Mn from the spent LiMn 2 O 4 cathode materials . Using the TG-DSC-FTIR, XRD, SEM-EDS and ICP methods, the detailed mechanism of reduction roasting process was revealed, showing that the Mn 4+ and Mn 3+ in the spinel structure of LiMn 2 O 4 were reduced by the NH 4 + from the molten ammonium salt, and transformed into water-soluble MnSO 4 and Li 2 Mn 2 (SO 4 ) 3 . According to the water-leaching performance of the roasting products, the sulfation conversion rate of Mn reaches 98.1 %, while Li is almost completely transformed under the optimal roasting conditions (475 ℃, 60 min). Using the NH 3 ·H 2 O-air leaching-system, complete separation of Li and Mn can be achieved. It was shown that the introduction of air into the ammonia solution at a rate of 0.2 L/min under the optimal leaching condition leads to Mn precipitation in the form of nanoscale Mn 3 O 4 particles with a precipitation rate of over 99.99 %, while Li still remains completely leached. Based on the in situ detection of the oxidation reduction potential and pH during the selective leaching, the key mechanism of efficient Mn precipitation was revealed. that is, the increasing potential accelerates the oxidation of Mn(OH) 2 , and the rapid consumption of Mn(OH) 2 promotes the hydrolysis of Mn 2+ , thereby achieving a significant improvement in the separation efficiency of Li and Mn.
研究领域:
材料科学
·
环境工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）