Review
Environmental Sciences
Pijun Gong, Feng He, Junlin Xie, De Fang
Summary: Volatile organic compounds (VOCs) pose serious threats to human health and the ecological environment. Catalytic oxidation technology, due to its cost-effectiveness and high activity, is considered the most effective method for removing VOCs. This review summarizes the research progress in the catalytic oxidation of toluene using MnO2-based catalysts, including single MnO2, metal-doped MnO2, and supported MnO2 catalysts. The relationship between the chemical properties of MnO2 catalysts and toluene oxidation performance, as well as the catalytic reaction mechanisms, are focused on. Additionally, the effects of different crystal forms and morphologies on the catalytic toluene reaction are discussed, and the potential of MnO2 catalysts for the catalytic oxidation of toluene is proposed. The summary of these important findings is expected to serve as a valuable reference for the catalytic treatment of VOCs.
Article
Chemistry, Physical
Shipeng Wu, Huimin Liu, Zhen Huang, Hualong Xu, Wei Shen
Summary: In this study, a facile solvent-thermal-reduction strategy was used to fabricate an O-vacancy-rich porous MnO2 nanosheet catalyst (MnO2-PS) for propane catalytic oxidation. The catalyst exhibited improved redox ability and oxygen activation capacity, which accelerated the oxidation of light alkanes. Additionally, the catalyst possessed highly accessible surface and high density of exposed active sites, facilitating the adsorption and activation of reactant molecules.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Engineering, Chemical
Wei Liu, Wenjie Xiang, Nana Guan, Ruoyang Cui, Hao Cheng, Xi Chen, Zhongxian Song, Xuejun Zhang, Yinmin Zhang
Summary: The study found that constructing Co3O4-MnO2 interfaces significantly enhanced the catalytic activity of Co3O4/MnO2 catalysts, especially for Co3O4/α-MnO2 and Co3O4/γ-MnO2. The best catalyst Co3O4/α-MnO2 achieved a toluene conversion rate of 90% at 248 degrees Celsius and complete oxidation of toluene at 260 degrees Celsius, demonstrating great potential for practical applications.
SEPARATION AND PURIFICATION TECHNOLOGY
(2022)
Article
Chemistry, Physical
Yu Wang, Ji Wu, Gang Wang, Dengyao Yang, Tatsumi Ishihara, Limin Guo
Summary: This study examined two types of oxygen vacancies (V-O) and their concentrations in MnO2 catalysts, finding that catalysts with higher concentrations of V-O (FM) exhibited superior reaction rates and stability compared to other types. Additionally, in situ DRIFTS spectra revealed that higher concentrations of V-O (FM) sites accelerated the transformation of intermediates, leading to the oxidation of toluene into CO2 and H2O.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Engineering, Environmental
Jianyu Yun, Liangkai Wu, Qinglan Hao, Zihao Teng, Xin Gao, Baojuan Dou, Feng Bin
Summary: A series of CuO/CeO2 nanorod catalysts for toluene oxidation were prepared with non-equilibrium plasma, which can enhance the synergism between CuO active phase and CeO2 support, increase oxygen vacancies, and improve catalytic activity.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Engineering, Environmental
Yiqing Zeng, Kok-Giap Haw, Zhigang Wang, Yanan Wang, Shule Zhang, Plaifa Hongmanorom, Qin Zhong, Sibudjing Kawi
Summary: A novel double redox method was developed to synthesize highly active CuO-CeO2 (CuCe-DR) catalyst, which exhibits higher Ce3+ and Cu2+ ion concentrations and stronger Cu-Ce interaction compared to CuCe-C catalyst. CuCe-DR catalyst shows higher toluene oxidation performance and stability at low temperatures, attributed to the increased surface chemisorbed oxygen and improved redox properties.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Environmental Sciences
Tiancheng Wen, Jing Wang, Jian Zhang, Chao Long
Summary: In this study, α-MnO2 nanorods with tunable oxygen vacancies and hydroxyl groups were synthesized to enhance the deep oxidation of toluene. The as-synthesized nanorods showed superior activity and high COx selectivity, promoting the deep oxidation of toluene. It was found that the increase of oxygen vacancies and hydroxyl groups concentration contributed to the enhancement of performance.
ENVIRONMENTAL RESEARCH
(2023)
Article
Chemistry, Physical
Jia Zeng, Hongmei Xie, Zhao Liu, Xuecheng Liu, Guilin Zhou, Yi Jiang
Summary: This study demonstrates the tuning of oxygen vacancies on alpha-MnO2 for catalytic toluene oxidation, resulting in superior activity and stability. The control of oxygen vacancies weakens the Mn-O bond strength, increases the amount of surface adsorbed active oxygen species, and promotes catalytic activity.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Environmental
Wenxiu Gu, Chenqi Li, Jianhao Qiu, Jianfeng Yao
Summary: A facile and robust interface reaction method was developed for the controllable synthesis of hierarchically structured flower-like MnO2 hollow microspheres at a low cost. The as-prepared flower-like MnO2 hollow microspheres exhibited excellent low-temperature catalytic activity for toluene oxidation due to their high specific surface area, abundant oxygen vacancies, high content of Mn4+, numerous acidic sites, and strong acidity. This work provides a new strategy for the facile construction of high-performance volatile organic compounds oxidation catalysts with industrial application prospects.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Environmental Sciences
Ruimei Fang, Jing Huang, Xinyue Huang, Xiao'ai Luo, Yanjuan Sun, Fan Dong, Haibao Huang
Summary: Engineering alpha-MnO2 with abundant oxygen vacancies can enhance catalytic activity towards toluene oxidation. A simple method of reheating the samples under vacuum conditions facilitates the formation of oxygen vacancies, leading to improved toluene conversion rates. In-situ DRIFTS results show that the catalyst promotes the formation of benzaldehyde and ring-opening reactions, indicating enhanced catalytic performance for toluene oxidation.
Article
Chemistry, Multidisciplinary
Runnong Yang, Shaomin Peng, Bang Lan, Ming Sun, Zihao Zhou, Changyong Sun, Zihan Gao, Guichuan Xing, Lin Yu
Summary: The authors obtained oxygen defect-rich beta-MnO2 through a crystal phase transformation process, which showed high efficiency in low-temperature selective catalytic reduction of NO with NH3. The introduction of oxygen defects enhances the adsorption properties for reactants and decreases the energy barriers of NH2 formation, contributing to the high efficiency of low-temperature SCR activity.
Article
Chemistry, Physical
Cui Dong, Hui Wang, Yewei Ren, Zhenping Qu
Summary: The study found that treated MnO2 samples can increase their activity, with the MnO2-P catalyst showing the best catalytic performance. The formation of irregular pores on the surface of MnO2-P resulted in an increase in surface area and oxygen vacancy, enhancing the sample's adsorption capacity for toluene.
SURFACES AND INTERFACES
(2021)
Article
Chemistry, Physical
Yifei Li, Tingyu Chen, Shuaiqi Zhao, Peng Wu, Yanan Chong, Anqi Li, Yun Zhao, Guangxu Chen, Xiaojing Jin, Yongcai Qiu, Daiqi Ye
Summary: Coexistence of cobalt defects and oxygen vacancies has a significant effect on the performance of catalysts, improving the catalytic activity for toluene oxidation. A Co3-xO4-y catalyst with both cobalt defects and oxygen vacancies was synthesized, achieving over 90% toluene conversion under light illumination for 10 minutes at a temperature of around 180 degrees Celsius. Cobalt defects promote the formation of oxygen vacancies, which accelerate the conversion of intermediates and promote the degradation of toluene.
Article
Engineering, Chemical
Jiayang Gong, Shaopeng Rong, Jie Wang, Yefeng Zhou
Summary: Synthesizing catalysts using organic solvents is an appealing strategy to enhance oxygen vacancy concentration and catalytic activity. By employing the reducibility of ethylene glycol (EG), α-MnO2-EG was synthesized using a reduction strategy for toluene oxidation. The results demonstrated that EG significantly increased the oxygen vacancy concentration and catalytic activity of α-MnO2-EG. The α-MnO2-EG-160 catalyst exhibited a 30% higher oxygen vacancy concentration compared to α-MnO2-H2O, resulting in remarkable low-temperature catalytic performance (T90 = 183 degrees C), surpassing currently reported MnO2-based catalysts. The structure-activity relationship and toluene catalytic mechanism of α-MnO2-EG-160 based on oxygen vacancies were also proposed.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Engineering, Environmental
Ying Feng, Lingyun Dai, Zhiwei Wang, Yue Peng, Erhong Duan, Yuxi Liu, Lin Jing, Xun Wang, Ali Rastegarpanah, Hongxing Dai, Jiguang Deng
Summary: This study investigates the photothermal synergistic catalytic oxidation of toluene over single-atom Pt catalysts. The results show that under simulated solar irradiation, the conversion and CO2 yield of toluene can be significantly increased with the addition of CuO and the generation of reactive oxygen species. The findings highlight the importance of the synergistic effect between photo- and thermocatalysis in developing efficient and low-energy consumption pollutant treatment technologies.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Energy & Fuels
Yingna Du, Chen Huang, Wei Jiang, Qiangwei Yan, Yongfei Li, Gang Chen
Summary: In this study, anionic surfactants modified hydrotalcite was used as a flow improver for crude oil under low-temperature conditions. The modified hydrotalcite showed a significant viscosity reduction effect on crude oil. The mechanism of the modified hydrotalcite on viscosity and pour point of crude oil was explored through characterization and analysis of the modified hydrotalcite and oil samples.
Article
Energy & Fuels
Mohammad Saeid Rostami, Mohammad Mehdi Khodaei
Summary: In this study, a hybrid structure, MIL-53(Al)@MWCNT, was synthesized by combining MIL-53(Al) particles and -COOH functionalized multi-walled carbon nanotube (MWCNT). The hybrid structure was then embedded in a polyethersulfone (PES) polymer matrix to prepare a mixed matrix membrane (MMM) for CO2/CH4 and CO2/N2 separation. The addition of MWCNTs prevented MIL-53(Al) aggregation, improved membrane mechanical properties, and enhanced gas separation efficiency.
Article
Energy & Fuels
Yunlong Li, Desheng Huang, Xiaomeng Dong, Daoyong Yang
Summary: This study develops theoretical and experimental techniques to determine the phase behavior and physical properties of DME/flue gas/water/heavy oil systems. Eight constant composition expansion (CCE) tests are conducted to obtain new experimental data. A thermodynamic model is used to accurately predict saturation pressure and swelling factors, as well as the phase boundaries of N2/heavy oil systems and DME/CO2/heavy oil systems, with high accuracy.
Article
Energy & Fuels
Morteza Afkhamipour, Ebad Seifi, Arash Esmaeili, Mohammad Shamsi, Tohid N. Borhani
Summary: Non-conventional amines are being researched worldwide to overcome the limitations of traditional amines like MEA and MDEA. Adequate process and thermodynamic models are crucial for understanding the applicability and performance of these amines in CO2 absorption, but studies on process modeling for these amines are limited. This study used rate-based modeling and Deshmukh-Mather method to model CO2 absorption by DETA solution in a packed column, validated the model with experimental data, and conducted a sensitivity analysis of mass transfer correlations. The study also compared the CO2 absorption efficiency of DETA solution with an ionic solvent [bmim]-[PF6] and highlighted the importance of finding optimum operational parameters for maximum absorption efficiency.
Article
Energy & Fuels
Arastoo Abdi, Mohamad Awarke, M. Reza Malayeri, Masoud Riazi
Summary: The utilization of smart water in EOR operations has gained attention, but more research is needed to understand the complex mechanisms involved. This study investigated the interfacial tension between smart water and crude oil, considering factors such as salt, pH, asphaltene type, and aged smart water. The results revealed that the hydration of ions in smart water plays a key role in its efficacy, with acidic and basic asphaltene acting as intrinsic surfactants. The pH also influenced the interfacial tension, and the aged smart water's interaction with crude oil depended on asphaltene type, salt, and salinity.
Article
Energy & Fuels
Dongao Zhu, Kun Zhu, Lixian Xu, Haiyan Huang, Jing He, Wenshuai Zhu, Huaming Li, Wei Jiang
Summary: In this study, cobalt-based metal-organic frameworks (Co-based MOFs) were used as supports and co-catalysts to confine the NHPI catalyst, solving the leaching issue. The NHPI@Co-MOF with carboxyl groups exhibited stronger acidity and facilitated the generation of active oxygen radicals O2•, resulting in enhanced catalytic activity. This research provides valuable insights into the selection of suitable organic linkers and broadens the research horizon of MOF hybrids in efficient oxidative desulfurization (ODS) applications.
Article
Energy & Fuels
Edwin G. Hoyos, Gloria Amo-Duodu, U. Gulsum Kiral, Laura Vargas-Estrada, Raquel Lebrero, Rail Munoz
Summary: This study investigated the impact of carbon-coated zero-valent nanoparticle concentration on photosynthetic biogas upgrading. The addition of nanoparticles significantly increased microalgae productivity and enhanced nitrogen and phosphorus assimilation. The presence of nanoparticles also improved the quality of biomethane produced.
Article
Energy & Fuels
Yao Xiao, Asma Leghari, Linfeng Liu, Fangchao Yu, Ming Gao, Lu Ding, Yu Yang, Xueli Chen, Xiaoyu Yan, Fuchen Wang
Summary: Iron is added as a flocculant in wastewater treatment and the hydrothermal carbonization (HTC) of sludge produces wastewater containing Fe. This study investigates the effect of aqueous phase (AP) recycling on hydrochar properties, iron evolution and environmental assessment during HTC of sludge. The results show that AP recycling process improves the dewatering performance of hydrochar and facilitates the recovery of Fe from the liquid phase.
Article
Energy & Fuels
He Liang, Tao Wang, Zhenmin Luo, Jianliang Yu, Weizhai Yi, Fangming Cheng, Jingyu Zhao, Xingqing Yan, Jun Deng, Jihao Shi
Summary: This study investigated the influence of inhibitors (carbon dioxide, nitrogen, and heptafluoropropane) on the lower flammability limit of hydrogen and determined the critical inhibitory concentration needed for complete suppression. The impact of inhibitors on explosive characteristics was evaluated, and the inhibitory mechanism was analyzed with chemical kinetics. The results showed that with the increase of inhibitor quantity, the lower flammability limit of hydrogen also increased. The research findings can contribute to the safe utilization of hydrogen energy.
Article
Energy & Fuels
Zonghui Liu, Zhongze Zhang, Yali Zhou, Ziling Wang, Mingyang Du, Zhe Wen, Bing Yan, Qingxiang Ma, Na Liu, Bing Xue
Summary: In this study, high-performance solid catalysts based on phosphotungstic acid (HPW) supported on Zr-SBA-15 were synthesized and evaluated for the one-pot conversion of furfural (FUR) to γ-valerolactone (GVL). The catalysts were characterized using various techniques, and the ratio of HPW and Zr was found to significantly affect the selectivity of GVL. The HPW/Zr-SBA-15 (2-4-15) catalyst exhibited the highest GVL yield (83%) under optimized reaction conditions, and it was determined that a balance between Bronsted acid sites (BAS) and Lewis acid sites (LAS) was crucial for achieving higher catalytic performance. The reaction parameters and catalyst stability were also investigated.
Article
Energy & Fuels
Michael Stoehr, Stephan Ruoff, Bastian Rauch, Wolfgang Meier, Patrick Le Clercq
Summary: As part of the global energy transition, an experimental study was conducted to understand the effects of different fuel properties on droplet vaporization for various conventional and alternative fuels. The study utilized a flow channel to measure the evolution of droplet diameters over time and distance. The results revealed the temperature-dependent effects of physical properties, such as boiling point, liquid density, and enthalpy of vaporization, and showed the complex interactions of preferential vaporization and temperature-dependent influences of physical properties for multi-component fuels.
Article
Energy & Fuels
Yuan Zhuang, Ruikang Wu, Xinyan Wang, Rui Zhai, Changyong Gao
Summary: Through experimental validation and optimization of the chemical kinetic model, it was found that methanol can accelerate the oxidation reaction of ammonia, and methanol can be rapidly oxidized at high concentration. HO2 was found to generate a significant amount of OH radicals, facilitating the oxidation of methanol and ammonia. Rating: 7.5/10.
Article
Energy & Fuels
Radwan M. EL-Zohairy, Ahmed S. Attia, A. S. Huzayyin, Ahmed I. EL-Seesy
Summary: This paper presents a lab-scale experimental study on the impact of diethyl ether (DEE) as an additive to waste cooking oil biodiesel with Jet A-1 on combustion and emission features of a swirl-stabilized premixed flame. The addition of DEE to biodiesel significantly affects the flame temperature distribution and emissions. The W20D20 blend of DEE, biodiesel, and Jet A-1 shows similar flame temperature distribution to Jet A-1 and significantly reduces UHC, CO, and NOx emissions compared to Jet A-1.
Article
Energy & Fuels
Jiang Bian, Ziyuan Zhao, Yang Liu, Ran Cheng, Xuerui Zang, Xuewen Cao
Summary: This study presents a novel method for ammonia separation using supersonic flow and develops a mathematical model to investigate the condensation phenomenon. The results demonstrate that the L-P nucleation model accurately characterizes the nucleation process of ammonia at low temperatures. Numerical simulations also show that increasing pressure and concentration can enhance ammonia condensation efficiency.
Article
Energy & Fuels
Shiyuan Pan, Xiaodan Shi, Beibei Dong, Jan Skvaril, Haoran Zhang, Yongtu Liang, Hailong Li
Summary: Integrating CO2 capture with biomass-fired combined heat and power (bio-CHP) plants is a promising method for achieving negative emissions. This study develops a reliable data-driven model based on the Transformer architecture to predict the flowrate and CO2 concentration of flue gas in real time. The model validation shows high prediction accuracy, and the potential impact of meteorological parameters on model accuracy is assessed. The results demonstrate that the Transformer model outperforms other models and using near-infrared spectral data as input features improves the prediction accuracy.