Suchergebnisse

In this issue.World War II, medical care, LST landing barge, ships, New Caledonia, pentathal sodium, American Brass Co., Mt. Con, teamwork, basketball, copper cathodes, zinc slabs, Great Falls, Montana ; https://digitalcommons.mtech.edu/copper_commando/1048/thumbnail.jpg

Plasma-based nanoparticle synthesis techniques are attractive in many respects but suffer from a major drawback-low productivity. We demonstrate a technique by which the growth rate of copper nanoparticles has been substantially increased by collection of copper ions. A growth rate as high as 470 nm/s was obtained as compared to a growth rate of less than 3 nm/s in the case of growth by neutrals. The increased trapping of copper is explained as orbital motion limited (OML) collection of ions. Experimentally obtained nanoparticle growth rates are in good agreement with theoretical estimates of the OML ion collection rates. ; Funding Agencies|Knut and Alice Wallenberg Foundation|2012.0083|Swedish Research Council via the Linkoping Linneaus Environment LiLi-NFM|2008-6572|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University|2009 00971|

The electrochemical techniques are the subject of increasing interest on the environmental remediation methods thanks to their efficiency and their selectivity. It was classified among the cleanest methods because it does not produce sludge and undesirable intermediate byproducts. For these reasons, we have chosen this technology for the reduction of nitrites and nitrates ions from aqueous solutions. The objective of our study is the comparison of several cathodes materials performances, in order to promote an optimal electro-reduction of these ions. Indeed, we have used the copper, graphite, stainless steel and zinc as cathodes; among them, we have selected the most efficient on which we have optimized the operational conditions. The results suggested that the copper cathode was the most efficient for the reduction of both tested ions compared to the other tested materials. Therefore, the optimization of operational conditions allows us to fixed them at: scan rate=50mV/s, initial effluent concentration=100 mg/L, pH=7 and potential range of the cyclic voltammetry scanning of [-1,+1]V/SCE for both ions. Under these optimal parameters, the reduction yield after 45min was important that can achieve 96.5% and 99% for nitrites and nitrates respectively.

AbstractGreen hydrogen generation technologies are currently the most pressing worldwide issues, offering promising alternatives to existing fossil fuels that endanger the globe with growing global warming. The current research focuses on the creation of green hydrogen in alkaline electrolytes utilizing a Ni-Co-nano-graphene thin film cathode with a low overvoltage. The recommended conditions for creating the target cathode were studied by electrodepositing a thin Ni-Co-nano-graphene film in a glycinate bath over an iron surface coated with a thin copper interlayer. Using a scanning electron microscope (SEM) and energy-dispersive X-ray (EDX) mapping analysis, the obtained electrode is physically and chemically characterized. These tests confirm that Ni, Co, and nano-graphene are homogeneously dispersed, resulting in a lower electrolysis voltage in green hydrogen generation. Tafel plots obtained to analyze electrode stability revealed that the Ni-Co-nano-graphene cathode was directed to the noble direction, with the lowest corrosion rate. The Ni-Co-nano-graphene generated was used to generate green hydrogen in a 25% KOH solution. For the production of 1 kg of green hydrogen utilizing Ni-Co-nano-graphene electrode, the electrolysis efficiency was 95.6% with a power consumption of 52 kwt h−1, whereas it was 56.212. kwt h−1 for pure nickel thin film cathode and 54. kwt h−1 for nickel cobalt thin film cathode, respectively.

This paper presents the results of a comparative study of methods to prevent the loss of barium during the formation of thin-film proton-conducting electrolyte BaCe0.89Gd0.1Cu0.01O3-δ (BCGCuO) on La2NiO4+δ-based (LNO) cathode substrates by electrophoretic deposition (EPD). Three different methods of the BCGCuO film coating were considered: the formation of the BCGCuO electrolyte film without (1) and with a protective BaCeO3 (BCO) film (2) on the LNO electrode substrate and the formation of the BCGCuO electrolyte film on a modified La1.7Ba0.3NiO4+δ (LBNO) cathode substrate (3). After the cyclic EPD in six stages, the resulting BCGCuO film (6 μm) (1) on the LNO substrate was completely dense, but the scanning electron microscope (SEM) analysis revealed the absence of barium in the film caused by its intensive diffusion into the substrate and evaporation during the sintering. The BCO layer prevented the barium loss in the BCGCuO film (2); however, the protective film possessed a porous island structure, which resulted in the deterioration of the film's conductivity. The use of the modified LBNO cathode also effectively prevented the loss of barium in the BCGCuO film (3). A BCGCuO film whose conductivity behavior most closely resembled that of the compacts was obtained by using this method which has strong potential for practical applications in solid oxide fuel cell (SOFC) technology. © 2019 by the authors. ; Government Council on Grants, Russian Federation ; Funding: This research was funded by the Government of the Russian Federation (Agreement 02.A03.21.0006, Act 211).

AbstractLead–tin solder and lead service lines (LSLs) are important sources of lead, and after LSLs are removed, lead–tin solder will remain a major source of lead. A better understanding of the factors that control lead release from solder joints can help water utilities reduce lead. This paper reviews the reactions that take place at galvanic connections involving both lead–tin solder and lead pipe in contact with copper. A conceptual model based on these reactions was developed and is presented here to explain how such scale structure forms. The likely reactions that affect lead release for each of three cases, (1) no galvanic action, (2) lead anode and copper–brass cathode, and (3) lead cathode and copper–brass anode, are presented. The model also considers uniform corrosion that takes place on LSLs. This model should be useful when evaluating the impact of water quality changes on lead release from galvanic connections and LSLs.Article Impact StatementThe conceptual model sets the basis for water systems to anticipate the impact of water quality changes on lead release from lead surfaces.

Technologies for the Recycling of Electronic Wastes. Mechanical Recycling of Electronic Wastes for Materials Recovery / Viktor Laurmaa, Jaan Kers, Kaspar Tall, Valdek Mikli, Dmitri Goljandin, Kristiina Vilsaar, Priidu Peetsalu, Mart Saarna, Riho Tarbe, Lifeng Zhang -- Processing of Discarded Liquid Crystal Display for Recovering Indium / G Dodbiba, K Takahashi, T Fujita, N Sato, S Matsuo, K Okaya -- Green Pyrolysis of Used Printed Wiring Board Powders / Xiangjun Zuo, Lucas N W Damoah, Lifeng Zhang, Thomas Schuman, Jaan Kers -- Leaching of Lead from Solder Material Used in Electrical and Electronic Equipment / Manis Kumar Jha, Pankaj Choubey, Archana Kumari, Rakesh Kumar, Vinay Kumar, Jae-chun Lee -- Copper Recovery from Printed Circuit Board of E-Waste / Toyohisa Fujita, Hiroyuki Ono, Gjergj Dodbiba, Seiji Matsuo, Katsunori Okaya -- Recovery of Nickel from Leaching Liquor of Printed Circuit Board by Solvent Extraction / Adriana Johanny Murcia Santanilla, Beatriz Amaral Campos, Jorge Alberto Soares Tenorio, Denise Crocce Romano Espinosa -- Recovery of Copper from Printed Circuit Boards Waste by Bioleaching / Luciana Harue Yamane, Denise Crocce Romano Espinosa, Jorge Alberto Soares Ten̤rio -- Management and Technology Overview of Electronic Wastes. State of the Art in the Recycling of Waste Printed Wiring Boards / Xiangjun Zuo, Lifeng Zhang -- Overview of Electronics Waste Management in India / S Chatterjee, Krishna Kumar -- Prospective Scenario of E-Waste Recycling in India / Manis Kumar Jha, Abhishek Kumar, Vinay Kumar, Jae-chun Lee -- Methodology for Recovery Precious Metals: Gold, Silver and Platinum Group from Electronic Waste / Jaime Restrepo B Oscar, Oliveros G̤mez Honorio -- WEEE: Obsolete Mobile Phones Characterization Aiming at Recycling / Viviane Tavares Moraes, Denise Crocce Romano Espinosa, Jorge Alberto Soares Ten̤rio -- Poster: Recycling of Electronic Wastes. A Novel Process for Foam Glass Preparation from Waste CRT Panel Glass / Mengjun Chen, Fu-Shen Zhang, Jianxin Zhu -- Environmental Leaching Characteristics and Bioavailabilities of Waste Cathode Ray Tube Glass / Mengjun Chen, Fu-Shen Zhang, Jianxin Zhu -- Leaching Toxicity of Pb and Ba Containing in Cathode Ray Tube Glasses by SEP-TCLP / Mengjun Chen, Fu-Shen Zhang, Jianxin Zhu

Currently, in the European Union (EU), e-waste chain performance is assessed by technical indicators that aim to ensure system compliance with collection and recovery targets set by the WEEE Directive. This study proposes indicators to improve WEEE flow monitoring beyond the current overall weight-based approach, including complementary flows and treatment performance. A case study focused on the screen category in France is presented. In 2017, the collection rate of cathode-ray tube screens (CRT) was 68%, while for flat panel display (FPD) generated only 14% was collected. CRT screens have less precious and critical materials than FDP. Thus, elements like cobalt and gold highly concentrated in FPD, have a collection rate two to four times lower than elements such as copper (37%) which represents a high proportion in CRTs. Recycling is the main treatment in France. Nevertheless, the recycling rate per element varies significantly due to the low collection, and also the lack of technology and/or secondary raw materials market. The elements with higher recycling rates are base metals such as copper (28%), followed by precious metals like silver (23%), and gold (13%). Except for palladium, the recycling rate of the critical raw materials targeted in the study ranged from 6% (cobalt) to 0% (e.g. neodymium and indium). The results stress the need for indicators to support the development of WEEE chain from waste management to secondary (critical) raw materials suppliers.

International audience ; Currently, in the European Union (EU), e-waste chain performance is assessed by technical indicators that aim to ensure system compliance with collection and recovery targets set by the WEEE Directive. This study proposes indicators to improve WEEE flow monitoring beyond the current overall weight-based approach, including complementary flows and treatment performance. A case study focused on the screen category in France is presented. In 2017, the collection rate of cathode-ray tube screens (CRT) was 68%, while for flat panel display (FPD) generated only 14% was collected. CRT screens have less precious and critical materials than FDP. Thus, elements like cobalt and gold highly concentrated in FPD, have a collection rate two to four times lower than elements such as copper (37%) which represents a high proportion in CRTs. Recycling is the main treatment in France. Nevertheless, the recycling rate per element varies significantly due to the low collection, and also the lack of technology and/or secondary raw materials market. The elements with higher recycling rates are base metals such as copper (28%), followed by precious metals like silver (23%), and gold (13%). Except for palladium, the recycling rate of the critical raw materials targeted in the study ranged from 6% (cobalt) to 0% (e.g. neodymium and indium). The results stress the need for indicators to support the development of WEEE chain from waste management to secondary (critical) raw materials suppliers.

Hazard classification of waste is useful for the sound management and the recycling of potential resources. According to EU, the chemicals and waste policy areas are now converging, since the point is to minimise the adverse effects on human health and the environment, by phasing out hazardous chemicals or reducing release to air, water and soil. An exhaustive analysis of elements and substances and some tests are required to prove that a waste is non-hazardous. This can help to identify substances of concern not clearly evidenced by the waste management community. Many of these substances were legally used when the products were manufactured, but when the products become waste and are recovered, the now banned or restricted substance may still be contained in the recovered material. This classification can be used to improve the recycling of resources and to avoid dispersion of hazardous elements or substances during uncontrolled use (avoiding loops of hazardous substances). Some hard examples are plastics products with low concentration of antimony and brominated flame retardants from recycled plastics, concrete blocks with granulate of lead activated glass from cathode ray tubes, or dike reinforcement by sand and gravel from copper and lead slags. The different steps for classification are collection of information, sampling, analysis, tests, hypothesis of speciation of elements into mineral substances, collecting hazard statement codes of substances, and comparing weighted sum or maxima of concentrations or tests results with given concentration limits for each hazard property, or eventual use of now available internet sites, will be presented.

Hazard classification of waste is useful for the sound management and the recycling of potential resources. According to EU, the chemicals and waste policy areas are now converging, since the point is to minimise the adverse effects on human health and the environment, by phasing out hazardous chemicals or reducing release to air, water and soil. An exhaustive analysis of elements and substances and some tests are required to prove that a waste is non-hazardous. This can help to identify substances of concern not clearly evidenced by the waste management community. Many of these substances were legally used when the products were manufactured, but when the products become waste and are recovered, the now banned or restricted substance may still be contained in the recovered material. This classification can be used to improve the recycling of resources and to avoid dispersion of hazardous elements or substances during uncontrolled use (avoiding loops of hazardous substances). Some hard examples are plastics products with low concentration of antimony and brominated flame retardants from recycled plastics, concrete blocks with granulate of lead activated glass from cathode ray tubes, or dike reinforcement by sand and gravel from copper and lead slags. The different steps for classification are collection of information, sampling, analysis, tests, hypothesis of speciation of elements into mineral substances, collecting hazard statement codes of substances, and comparing weighted sum or maxima of concentrations or tests results with given concentration limits for each hazard property, or eventual use of now available internet sites, will be presented.