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Effect of Ce doping into V_(2)O_(5)-WO_(3)/TiO_(2) catalysts on the selective catalytic reduction of NO_(x) by NH_(3)

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Journal of Rare Earths 2017年第12期35卷 1206-1215页

作者： Mengyin Chen Mengmeng Zhao Fushun Tang Le Ruan Hongbin Yang Ning Li College of Chemistry and Bioengineering Guilin University of TechnologyCollaborative Innovation Center for Exploration of Hidden Nonferrous Metal DepositsDevelopment of New Materials in Guangxi Guangxi solid waste management center

In this work, the effectiveness of V2O5-WO3/TiO2 catalysts modified with different CeO2 contents by impregnation and co-precipitation methods on the selective catalytic reduction of NOxby NH3 have been studied comparatively by various experimental techniques. The results showed that the NO conversion of V2O5-WO3/CeO2-TiO2 catalysts modified by co-precipitation method obviously increased with the Ce doping contents in the studied range below 20%（All Ce contents are in mass fractions）, but the NO conversion of V2O5-WO3/CeO2/TiO2 catalysts modified by impregnation methods was lower than V2O5-WO3/CeO2-TiO2 catalysts especially beyond 2.5% Ce doping contents. The V2O5-WO3/CeO2-TiO2 catalysts showed better SCR activity, wider reaction window, and higher sulfur and water resistance. The characterization results elucidated that the modified catalysts by co-precipitation method exhibited higher specific surface area, much better dispersity of Ce component, more Ce^（3＋）species and more Br？nsted acid sites than that by impregnation. The vacancies caused by more Ce^（3＋）species were favorable for more NO oxidation to NO2, and the interaction between Ce species and WOxspecies generated more Br？nsted acid sites. It could be supposed that dispersed Ce Oxspecies and WOxspecies offered more second active centers respectively to adsorb oxygen and activate ammonia as co-catalysis to the primary active center of V ions, thus facilitated the better SCR activity of modified V2O5-WO3/CeO2-TiO2 catalysts by coprecipitation methods. The co-precipitation methods with Ce component were more suitable for production of modified commercial V2O5-WO3/TiO2 catalysts.

关键词： V2O5-WO3/TiO2 catalysts Ce doping methods NH3 selective catalytic reduction NOx Dispersion state Reducibility Br?nsted acid sites

Removing and recycling mercury from scrubbing solution produced in wet nonferrous metal smelting flue gas purification process

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Journal of Environmental Sciences 2021年第5期33卷 59-68页

作者： Shu Yang Ziliang Li Kang Yan Xi Zhang Zhifeng Xu Wanrong Liu Zhilou Liu Hui Liu School of Metallurgy Engineering JiangXi University of Science and TechnologyGanzhou 341000China School of Metallurgy and Environment Central South UniversityChangsha 410083China Institute of Green Metallurgy and Process Intensification Ganzhou 341000China solid waste and chemicals management center Ministry of Environmental ProtectionBeijing 100024China

Wet purification technology for nonferrous metal smelting flue gas is important for mercury removal;however, this technology produces a large amounts of spent scrubbing solution that contain mercury. The mercury in these scrubbing solutions pose a great threat to the environment. Therefore, this research provides a novel strategy for removing and recycling mercury from the scrubbing solution, which is significant for decreasing mercury pollution while also allowing for the safe disposal of wastewater and a stable supply of mercury resources. Some critical parameters for the electrochemical reduction of mercury were studied in detail. Additionally, the electrodeposition dynamics and electroreduction mechanism for mercury were evaluated. Results suggested that over 92.4% of mercury could be removed from the scrubbing solution in the form of a Hg-Cu alloy under optimal conditions within 150 min and with a current efficiency of approximately 75%. Additionally, mercury electrodeposition was a quasi-reversible process, and the controlled step was the mass transport of the reactant. A pre-conversion step from Hg(Tu)_(4)^(2+) to Hg(Tu)_(3)^(2+) before mercury electroreduction was necessary. Then, the formed Hg(Tu)_(3)^(2+) on the cathode surface gained electrons step by step. After electrodeposition, the mercury in the spent cathode could be recycled by thermal desorption. The results of the electrochemical reduction of mercury and subsequent recycling provides a practical and easy-to-adopt alternative for recycling mercury resources and decreasing mercury contamination.

关键词： Mercury Electrodeposition Scrubbing solution Pollution control

Overlooked risk of microplastics from municipal solid waste-storage site

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Frontiers of Environmental Science & Engineering 2024年第10期18卷 103-114页

作者： Ying Hu Shuli Guo Dongsheng Shen Jiali Shentu Li Lu Shengqi Qi Min Zhu Yuyang Long Zhejiang Provincial Key Laboratory of solid waste Treatment and Recycling Zhejiang Engineering Research Center of Non-ferrous Metal Waste RecyclingSchool of Environmental Science and EngineeringZhejiang Gongshang UniversityHangzhou 310012China

Municipal solid waste(MSW)storage sites are potential and overlooked contributors to microplastic(MP)***,the distribution and dispersion characteristics of MPs at MSW storage sites were investigated through modeling,sampling analysis,and prediction *** results indicated a notable adsorption phenomenon of MPs on smooth surfaces within such sites,achieving high saturation levels and making MPs prone to re-release by airflow *** analysis revealed that the MP concentrations on these surfaces varied from 4.48×10^(5) to 1.90×10^(6) n/m^(2) and that MPs predominantly accumulated in the corner ***,MP accumulation on wall surfaces can be reduced by 76.4%using washing *** majority of MPs were under 50μm in size and were primarily in fragment *** activities such as ventilation and waste handling were identified to amplify the airborne spread of *** atmospheric concentrations of MPs peaked seasonally,with concentrations of 28.25 n/m^(3) in summer and 3.90 n/m^(3) in winter,and the spatial dispersion ranged from 14.98 to 124.08 km^(2) per *** study highlights that MSW storage sites are substantial yet overlooked sources of MP pollution,where wall surfaces play a critical role in MP adsorption and *** implementation of robust management and cleaning protocols is essential to mitigate the environmental footprint of MPs emanating from these *** study also provides a typical case for the precise prevention and control of MPs in the environment.

关键词： Municipal solid waste storage sites Microplastic Adsorption Dispersion Emerging pollution

Evaluating the treatment of E-waste──a case study of discarded refrigerators

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Journal of China University of Mining and Technology 2008年第3期18卷 454-458页

作者： DENG Jian-jun WEN Xue-feng ZHAO Yue-min School of Chemical Engineering and Technology China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China National center of solid waste management MEP Beijing 100029 China

Disassembly and recycling of E-waste creates a series of environmental problems. The selection of a technologically reliable, environmentally friendly, economically affordable and socially acceptable recycling technology for E-waste is a significant question. This study establishes a Monte-Carlo mathematical model of cost minimization, given the constraints of environmentally sound handling of the e-waste, in the context of Crystal Ball risk assessment and evaluation software. By following the streams of the different treatment processes, which consist of various technologies including disassembly, recycling and disposal, the econom-ics of various possibilities were identified and the optimal recycling technology proposed. The key factors of the proposed scenarios were determined by using sensitivity analysis. The results of this study show that, for discarded refrigerators, the operating life span plays the key role. The model supports maintenance and resale of the short lived refrigerators. For the longer lived refrigerators material recycling is recommended by the model. Sensitivity analysis shows that purchase cost, plastic sale price, condenser sale price and disassembly costs are the main effects. This study provides a significant technical support for policy making in E-waste management.

关键词： E-waste end-of-life refrigerator recycling Monte-carlo method sensitivity analysis

Uranium speciation in coal bottom ash investigated via X-ray absorption fine structure and X-ray photoelectron spectra

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Journal of Environmental Sciences 2018年第12期30卷 88-94页

作者： Yinglong Sun Menxin Wu Lirong Zheng Bangda Wang Yi Wang National Meteorological center China Meteorological Administration Key Laboratory for solid waste management and Environment Safety Ministry of Education of China Tsinghua University Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences

Similar to chromium contamination, the environmental contamination caused by uranium in radioactive coal bottom ash（CBA） is primarily dependent on the chemical speciation of uranium. However, the relationship between uranium speciation and environmental contamination has not been adequately studied. To determine the relationship between uranium speciation and environmental contamination, X-ray absorption fine structure（XAFS） and X-ray photoelectron spectra（XPS） analyses were performed to determine the uranium speciation in CBA exposed to different chemical environments and simulated natural environments. The leachability of the different forms of uranium in the CBA was studied via a simulated acid rain leaching experiment, and the results showed that 57.0% of the total uranium was leached out as U（VI）. The results of a linear combination fit（LCF）of the X-ray absorption near edge structure（XANES） spectrum revealed that in the raw CBA, the uranium mainly occurred as U_3O_8（71.8%）. However, in the iron-rich particles, the uranium mainly occurred as UO_2（91.9%） after magnetic separation. Magnetite is a ubiquitous ferrousbearing oxide, and it was effective for the sorption of U（IV）. The result of FeSO_4 leaching experiment indicated that 96.57% of total uranium was reduced from U（VI） to U（IV） when infiltrated with the FeSO_4 solution for 6 months. This result clearly demonstrated the changes in chemical valence of uranium in the coal ash and provided a conceptual principle for preventing uranium migration from ash to the surrounding soil and plants.

关键词： Coal bottom ash Uranium speciation XAFS Uranium migration

A Mini-Review on Metal Recycling from Spent Lithium Ion Batteries

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Engineering 2018年第3期4卷 361-370页

作者： Xiaohong Zheng Zewen Zhu Xiao Lin Yi Zhang Yi He Hongbin Cao Zhi Sun Beijing Engineering Research center of Process Pollution Control Key Laboratory of Green Process and Engineering Division of Environment Technology and Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Toixing High School of Jiangsu Province Toixing 225400 China solid waste and chemicals management center Ministry of Ecology and Environment of the People's Republic of China Beijing 100029 China

The rapid growth of lithium ion batteries （LIBs） for portable electronic devices and electric vehicles has resulted in an increased number of spent LIBs. Spent LIBs contain not only dangerous heavy metals but also toxic chemicals that pose a serious threat to ecosystems and human health. Therefore, a great deal of attention has been paid to the development of an efficient process to recycle spent LIBs for both economic aspects and environmental protection. In this paper, we review the state-of-the-art processes for metal recycling from spent LIBs, introduce the structure of a LIB, and summarize all available technologies that are used in different recovery processes. It is notable that metal extraction and pretreatment play impor- tant roles in the whole recovery process, based on one or more of the principles of pyrometallurgy, hydrometallurgy, biometallurgy, and so forth. By further comparing different recycling methods, existing challenges are identified and suggestions for improving the recycling effectiveness can be proposed.

关键词： Spent lithium ion batteries Valuable metals Pretreatment Metal extraction Product preparation Recycling

Pollution characteristics of polycyclic aromatic hydrocarbons in common used mineral oils and their transformation during oil regeneration

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Journal of Environmental Sciences 2017年第6期29卷 247-253页

作者： Xiaohui Wu Bo Yue Yi Su Qi Wan Qifei Huang Qunhui Wang Hongying Cai State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Beijing 100012China Civil and Environmental Engineering Institute University of Science and Technology BeijingBeijing 100083China The solid waste management center of Chongqing Chongqing 401147China

The pollution characteristic of polycyclic aromatic hydrocarbons （PAHs） in common used mineral oils, semi-refined oils, refined oils and solid wastes produced during the used mineral oil regeneration process was analyzed. The results showed that total PAHs content in six common used mineral oils was as follows： used engine oil 〉 used quenching oil 〉 used casting oil 〉 used hydraulic oil 〉 used antimst oil 〉 used industrial lubricating oil. Furthermore, this order was dependent on the source of PAHs and oil working temperatures. Additionally, total PAt-Is content in regenerated oils was as follows： semi-refined oil 〉 refined oil 〉 crude oil, which was related to the catalytic cracking process of crude oil and adsorption refining process of semi-refined oil. The ranking of total PAHs content in regenerated wastes varied depending on the regeneration technology used as follows： waste adsorption sand 〉 acid sludge 〉 waste clay 〉 precipitation sludge 〉 cracked residue. In all types of used mineral oils and regenerated wastes, the maximum and minimum proportions of the total PAHs content were composed of 2-3 ring-PAHs and 5-6 ring-PAHs, respectively. The majority of PAHs in the used mineral oils entered into regenerated wastes during regeneration process, while a small number remained in the regenerated oil.

关键词： Used mineral oilPAHsPollution characteristicsRegenerationTransformation

Treatment and resource recovery from inorganic fluoride-containing waste produced by the pesticide industry

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Journal of Environmental Sciences 2015年第5期27卷 21-29页

作者： Yang Li Hua Zhang Zhiqi Zhang Liming Shao Pinjing He State Key Laboratory of Pollution Control and Resources Reuse Tongji University Institute of waste Treatment and Reclamation Tongji University Research and Training center on Rural waste management Ministry of Housing and Urban–Rural Development of P.R.China

The rapid development of the fluorinated pesticide industry has produced a large amount of fluorine-containing hazardous waste, especially inorganic fluoride-containing waste（IFCW）. A two-step process, including extraction and recovery, was developed to recover fluorine as synthetic cryolite from IFCW produced by the pesticide industry. The optimum conditions for extraction were found to be a temperature of 75℃, an initial p H（p Hi） of 12, a4-hr incubation time and a liquid-to-solid ratio of 40 m L/g; these conditions resulted in a fluorine extraction ratio of 99.0%. The effects of p H and the F/Al molar ratio on fluorine recovery and the compositional, mineralogical and morphological characteristics of the cryolite products were investigated. Field-emission scanning electron microscopy of recovered precipitates showed changes in morphology with the F/Al molar ratio. Coupling Fourier transform and infrared spectroscopy, X-ray diffraction indicated that the formation of Al F3-6was restricted as increasing p H. Both the amount of fluorine recovered and the quality of the cryolite were optimized at initial p H = 3 and a F/Al molar ratio 5.75. This study proposed a reliable and environmentally friendly method for the treatment of fluoridecontaining wastes, which could be suitable for industrial applications.

关键词： Fluoride-containing waste Fluorine extraction Fluorine recovery Cryolite

Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques

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Journal of Environmental Sciences 2015年第1期27卷 298-308页

作者： Yumin Zhu Hua Zhang Liming Shao Pinjing He State Key Laboratory of Pollution Control and Resources Reuse Tongji University Institute of waste Treatment and Reclamation Tongji University Research and Training center on Rural waste management Ministry of Housing and Urban–Rural Development of P.R. China

Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste（MSW）. In this study, we investigated fine particles of 〈 2 mm, which are small fractions in MSW but constitute a significant component of the total heavy metal content, using bulk detection techniques. A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of 〈 10 μm within the fine particles. Zn–Cu, Pb–Fe and Fe–Mn–Cr had significant correlations in terms of spatial distribution. The overlapped enrichment, spatial association, and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions（such as scraps of organic wastes or ceramics） or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction（such as food waste） is a preferable means of facilitating the beneficial utilization of the stabilized products.

关键词： Municipal solid waste Fine particle Synchrotron radiation Micro-analytical technique Metal