The Experts below are selected from a list of 13740 Experts worldwide ranked by ideXlab platform
Guangwen Zhang - One of the best experts on this subject based on the ideXlab platform.
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cleaner utilization of non metallic components in separation tailings of waste printed circuit board Pyrolysis oil calorific value and building aggregate
Journal of Cleaner Production, 2020Co-Authors: Chunchen Nie, Yanyan Wang, Hao Zhang, Yuankang Zhang, Yiqing Zhang, Zhengqing Yan, Xianjun Lyu, Youjun Tao, Jun Qiu, Guangwen ZhangAbstract:Abstract The resource utilization of non-metallic components (NMC) in waste printed circuit boards (WPCBs) was concerned in this study. Pyrolysis oil, calorific value and building materials in NMC were recovered and utilized. Organic matter in NMC was recycled in the form of Pyrolysis oil by Pyrolysis Treatment. The Pyrolysis temperature was determined by thermogravimetric analysis. The composition of Pyrolysis oil was analyzed by GC-MS. Thermogravimetric analysis shows that 300–400 °C is the main temperature range for the formation of Pyrolysis oil, and the weight loss reaches 20.58%. Further, weight loss only achieves 6.38% within 400–800 °C. The GC-MS results show that the main components are phenols, which can be used for the synthesis of oil-based resins. In addition, the calorific value of Pyrolysis residues was measured. The results show that the calorific value of Pyrolysis residues obtained at 400 °C and 800 °C reaches 4.62 MJ/kg and 3.76 MJ/kg respectively in aerobic conditions. Finally, the residue without calorific value was prepared into building material with cement, and the compressive strength is proven to reach 9.43 MPa. This study provides a practical approach to the reutilization of NMC in WPCBs.
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application of mechanical crushing combined with Pyrolysis enhanced flotation technology to recover graphite and licoo2 from spent lithium ion batteries
Journal of Cleaner Production, 2019Co-Authors: Guangwen Zhang, Haifeng Wang, Yi Feng, Weining Xie, Xiangnan ZhuAbstract:Abstract In this study, a novel process of mechanical crushing combined with a Pyrolysis-enhanced flotation was developed to recover LiCoO2 and graphite from spent lithium-ion batteries, which lays the foundation for the subsequent metallurgical process. Pyrolysis technology was used to solve the problem of low flotation efficiency of electrode materials. The Pyrolysis characteristics of the electrode materials were carefully analyzed, and based on the results, the effects of Pyrolysis Treatment on the surface micro-characteristics, surface element chemical states, and mineral phases of electrode materials were fully investigated to explore the Pyrolysis flotation enhancement mechanism. Afterwards, flotation methods were utilized to separate LiCoO2 from graphite. Surface micro-characterization analysis showed that the residual organic binders and electrolytes were the main reason that resulted in a low flotation efficiency of electrode materials. The thermogravimetric analysis and Pyrolysis products indicated that the organic binders and electrolyte can be removed at a Pyrolysis temperature of 500 °C. X-ray powder diffractometer analysis demonstrated that the electrode particle mineral phases were not altered at a Pyrolysis temperature of less than 550 °C. The optimum flotation behavior was presented at a Pyrolysis temperature of 550 °C with heating rate of 10 °C/min and Pyrolysis time of 15 min LiCoO2 grade is 94.72% with the recovery of 83.75% in this condition. Two stage Pyrolysis-enhanced flotation processes can further upgrade the LiCoO2 grade to 98.00%. This research proposes a novel method to improve the flotation efficiency of electrode materials, and the relevant mechanism is explored, which provides an alternative recycling flowchart of spent lithium-ion batteries.
Capucine Dupont - One of the best experts on this subject based on the ideXlab platform.
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Unraveling the Properties of Biomass-Derived Hard Carbons upon Thermal Treatment for a Practical Application in Na-Ion Batteries
Energies, 2020Co-Authors: Carolina Del Mar Saavedra Rios, Loic Simonin, Camelia Matei Ghimbeu, Arnaud De Geyer, Capucine DupontAbstract:Biomass is gaining increased attention as a sustainable and low-cost hard carbon (HC) precursor. However, biomass properties are often unexplored and unrelated to HC performance. Herein, we used pine, beechwood, miscanthus, and wheat straw precursors to synthesize HCs at 1000 • C, 1200 • C and 1400 • C by a two-steps Pyrolysis Treatment. The final physicochemical and electrochemical properties of the HC evidenced dissimilar trends, mainly influenced by the precursor's inorganic content, and less by the thermal Treatment. Pine and beechwood HCs delivered the highest reversible capacity and coulombic efficiency (CE) at 1400 • C of about 300 mAh·g −1 and 80%, respectively. This performance can be attributed to the structure derived from the high carbon purity precursors. Miscanthus and wheat straw HC performance was strongly affected by the silicon, potassium, and calcium content in the biomasses, which promoted simultaneous detrimental phenomena of intrinsic activation, formation of a silicon carbide phase, and growth of graphitic domains with temperature. The latter HCs delivered 240-200 mAh·g −1 of reversible capacity and 70-60% of CE, respectively, at 1400 • C. The biomass precursor composition, especially its inorganic fraction, seems to be a key parameter to control, for obtaining high performance hard carbon electrodes by direct Pyrolysis process.
Bai Yang - One of the best experts on this subject based on the ideXlab platform.
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reversible off on fluorescence of zn2 passivated carbon dots mechanism and potential for the detection of edta and zn2
Langmuir, 2018Co-Authors: Mingxi Yang, Qiuling Tang, Yang Meng, Junjun Liu, Tanglue Feng, Xiaohuan Zhao, Shoujun Zhu, Bai YangAbstract:Zn2+-passivated carbon dots (named Z-CDs) were synthesized from zinc gluconate for the first time through a one-step Pyrolysis Treatment. The mechanism of Zn2+-enhanced fluorescence was carefully investigated, and a new strategy to passivate the surfaces of CDs by Zn2+ was proposed. Inspired by the complexation reaction between Zn2+ and ethylenediaminetetraacetic acid (EDTA), a reversible “off–on” fluorescent nanosensor for the detection of EDTA and Zn2+ was constructed based on the depassivation and repassivation of Z-CDs, with a limit of detection as low as 3.2 × 10–7 M and 5.1 × 10–7 M, respectively. The proposed Z-CD-based nanosensor had been further utilized for EDTA and Zn2+ monitoring in tap water with excellent recovery. To the best of our knowledge, this was the first report of a fluorescence-based sensor of EDTA and a turn-on sensor of Zn2+ based on CDs with reversible detection capability. Also, benefiting from the low toxicity of zinc, Z-CDs were applied for multicolor bioimaging and in vitro ...
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Reversible “Off–On” Fluorescence of Zn2+-Passivated Carbon Dots: Mechanism and Potential for the Detection of EDTA and Zn2+
2018Co-Authors: Mingxi Yang, Qiuling Tang, Yang Meng, Junjun Liu, Tanglue Feng, Xiaohuan Zhao, Shoujun Zhu, Bai YangAbstract:Zn2+-passivated carbon dots (named Z-CDs) were synthesized from zinc gluconate for the first time through a one-step Pyrolysis Treatment. The mechanism of Zn2+-enhanced fluorescence was carefully investigated, and a new strategy to passivate the surfaces of CDs by Zn2+ was proposed. Inspired by the complexation reaction between Zn2+ and ethylenediaminetetraacetic acid (EDTA), a reversible “off–on” fluorescent nanosensor for the detection of EDTA and Zn2+ was constructed based on the depassivation and repassivation of Z-CDs, with a limit of detection as low as 3.2 × 10–7 M and 5.1 × 10–7 M, respectively. The proposed Z-CD-based nanosensor had been further utilized for EDTA and Zn2+ monitoring in tap water with excellent recovery. To the best of our knowledge, this was the first report of a fluorescence-based sensor of EDTA and a turn-on sensor of Zn2+ based on CDs with reversible detection capability. Also, benefiting from the low toxicity of zinc, Z-CDs were applied for multicolor bioimaging and in vitro detection in cells
Howard A. Chase - One of the best experts on this subject based on the ideXlab platform.
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catalytic microwave Pyrolysis of waste engine oil using metallic Pyrolysis char
Applied Catalysis B-environmental, 2015Co-Authors: Su Shiung Lam, Rock Keey Liew, Chin Kui Cheng, Howard A. ChaseAbstract:Microwave Pyrolysis was performed on waste engine oil pre-mixed with different amounts of metallic-char catalyst produced previously from a similar microwave Pyrolysis process. The metallic-char catalyst was first prepared by preTreatment with calcination followed by analyses to determine its various properties. The heating characteristics of the mixture of waste oil and metallic-char during the Pyrolysis were investigated, and the catalytic influence of the metallic-char on the yield and characteristics of the Pyrolysis products are discussed with emphasis on the composition of oil and gaseous products. The metallic-char, detected to have a porous structure and high surface area (124 m2/g), showed high thermal stability in a N2 atmosphere and it was also found to have phases of metals and metal oxides attached or adsorbed onto the char, representing a potentially suitable catalyst to be used in Pyrolysis cracking process. The metallic-char initially acted as an adsorptive-support to adsorb metals, metal oxides and waste oil. Then, the char became a microwave absorbent that absorbed microwave energy and heated up to a high temperature in a short time and it was found to generate arcing and sparks during microwave Pyrolysis of the waste oil, resulting in the formation of hot spots (high temperature sites with temperature up to 650 °C) within the reactor under the influence of microwave heating. The presence of this high temperature metallic-char, the amounts of which are likely to increase when increasing amounts of metallic-char were added to the waste oil (5, 10, and 20 wt% of the amount of waste oil added to the reactor), had provided a reducing chemical environment in which the metallic-char acted as an intermediate reductant to reduce the adsorbed metals or metal oxides into metallic states, which then functioned as a catalyst to provide more reaction sites that enhanced the cracking and heterogeneous reactions that occurred during the Pyrolysis to convert the waste oil to produce higher yields of light hydrocarbons, H2 and CO gases in the Pyrolysis products, recording a yield of up to 74 wt% of light C5–C10 hydrocarbons and 42 vol% of H2 and CO gases. The catalytic microwave Pyrolysis produced 65–85 wt% yield of Pyrolysis-oil containing C5–C20 hydrocarbons that can potentially be upgraded to produce transport-grade fuels. In addition, the recovered Pyrolysis-gases (up to 33 wt%) were dominated by aliphatic hydrocarbons (up to 78 vol% of C1–C6 hydrocarbons) and significant amounts of valuable syngas (up to 42 vol% of H2 and CO in total) with low heating values (LHV) ranging from 4.7 to 5.5 MJ/m3, indicating that the Pyrolysis-gases could also be used as a gaseous fuel or upgraded to produce more hydrogen as a second-generation fuel. The results indicate that the metallic-char shows advantages for use as a catalyst in microwave Pyrolysis Treatment of problematic waste oils.
Chase Howard - One of the best experts on this subject based on the ideXlab platform.
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Catalytic microwave Pyrolysis of waste engine oil using metallic Pyrolysis char
Applied Catalysis B: Environmental, 2015Co-Authors: Lam, Su Shiung, Liew, Rock Keey, Cheng, Chin Kui, Chase HowardAbstract:Microwave Pyrolysis was performed on waste engine oil pre-mixed with different amounts of metallic-char catalyst produced previously from a similar microwave Pyrolysis process. The metallic-char catalyst was first prepared by preTreatment with calcination followed by analyses to determine its various properties. The heating characteristics of the mixture of waste oil and metallic-char during the Pyrolysis were investigated, and the catalytic influence of the metallic-char on the yield and characteristics of the Pyrolysis products are discussed with emphasis on the composition of oil and gaseous products. The metallic-char, detected to have a porous structure and high surface area (124 m2/g), showed high thermal stability in a N2 atmosphere and it was also found to have phases of metals and metal oxides attached or adsorbed onto the char, representing a potentially suitable catalyst to be used in Pyrolysis cracking process. The metallic-char initially acted as an adsorptive-support to adsorb metals, metal oxides and waste oil. Then, the char became a microwave absorbent that absorbed microwave energy and heated up to a high temperature in a short time and it was found to generate arcing and sparks during microwave Pyrolysis of the waste oil, resulting in the formation of hot spots (high temperature sites with temperature up to 650 °C) within the reactor under the influence of microwave heating. The presence of this high temperature metallic-char, the amounts of which are likely to increase when increasing amounts of metallic-char were added to the waste oil (5, 10, and 20 wt% of the amount of waste oil added to the reactor), had provided a reducing chemical environment in which the metallic-char acted as an intermediate reductant to reduce the adsorbed metals or metal oxides into metallic states, which then functioned as a catalyst to provide more reaction sites that enhanced the cracking and heterogeneous reactions that occurred during the Pyrolysis to convert the waste oil to produce higher yields of light hydrocarbons, H2 and CO gases in the Pyrolysis products, recording a yield of up to 74 wt% of light C5–C10 hydrocarbons and 42 vol% of H2 and CO gases. The catalytic microwave Pyrolysis produced 65–85 wt% yield of Pyrolysis-oil containing C5–C20 hydrocarbons that can potentially be upgraded to produce transport-grade fuels. In addition, the recovered Pyrolysis-gases (up to 33 wt%) were dominated by aliphatic hydrocarbons (up to 78 vol% of C1–C6 hydrocarbons) and significant amounts of valuable syngas (up to 42 vol% of H2 and CO in total) with low heating values (LHV) ranging from 4.7 to 5.5 MJ/m3, indicating that the Pyrolysis-gases could also be used as a gaseous fuel or upgraded to produce more hydrogen as a second-generation fuel. The results indicate that the metallic-char shows advantages for use as a catalyst in microwave Pyrolysis Treatment of problematic waste oils. [Graphical abstract - see article]The authors acknowledges the financial support by the Ministry of Science, Technology, and Innovation Malaysia (MOSTI), Ministry of Higher Education Malaysia (MOHE), and University Malaysia Terengganu for the conduct of the research under the E-Science fund (UMT/RMC/SF/13/52072(5), Vot No: 52072), the Fundamental Research Grant Scheme (Project No: FRGS/1/2013/TK05/UMT/02/2, Vot No: 59296), and the Research Acculturation Grant Scheme (Project No: RAGS/2012/UMT/TK07/3, Vot No: 57085).This is the author accepted manuscript. The final version is available from [publisher] via http://dx.doi.org/10.1016/j.apcatb.2015.04.01
