Recycled prospects

Table 1.1 Recycling prospects and requirements of basic materials...

RECYCLING PROSPECTS FOR FUTURE ADVANCED BATTERY SYSTEMS Sodium/Sulfur (Na/S)... 

Palladium is an expensive metal and this imposes limits on the thickness of material that can be used for hydrogen purification in competition with other industrial methods. Emonts et al. estimated that films less than about 5 p,m in thickness need to be used in a fuel-cell methanol reformer [7], while Criscuoli et al. [8] concluded that 20 p,m is an upper limit for membranes to be economically competitive. These economic estimates overlook the possibility of recycling the palladium or palladium alloy. This becomes a very real possibility in the use of free-standing membranes rather than composite structures with other metals or ceramics. Recycling prospects probably increase the thickness constraint to something between 5 jxm and 8 p.m, a value that is also consistent with factors such as limitations on the volume of space occupied by a multiple membrane assembly. 

European Commission, Joint Research Centre, Institute for Prospective Technological Studies, Sustainable Production and Consumption Unit (SUSPROC) Waste and recycling. Last updated 6 March 2011. http //susproc.jrc.ec.europa.eu/activities/waste/... 

Several methods have been described to liberate the hydroxyl groups from 24 to produce the water-soluble, tetrahydroxyl bidentate ligand 25 [52, 53b]. Water-soluble ligands are of interest due to the prospect of recycling the catalyst into an aqueous phase, ideally without loss of performance. The enantiomeric hydrogenation of itaconic acid was performed in aqueous methanol over a range of solvent compositions (MeOH H20, 9 1 to 3 97), with consistently excellent levels of performance (100% conversion, 99% ee, SCR 100, 12 h) [52 b]. Interest-... 

The French Act of 28 June 2006 on a sustainable management of nuclear materials and radioactive waste sets plans for a prototype of fast neutron reactor to proceed in the 2020s with demonstrations of advanced recycling modes that are anticipated in 2012 to offer best prospects of industrial applications. 

Centi G, Perathoner S. Opportunities and prospects in the chemical recycling of carbon dioxide to fuels. Catal Today. 2009 148(3-4) 191-205. 

As in many other areas of catalysis in ionic liquids, the research of the past years in ionic liquid supported olefin metathesis has been dominated by demonstrating the general feasibility in this reaction medium. With the development of the task-specific complexes new prospects have been opened and the improved recyclability of these compounds relative to the common metathesis catalysts is impressive. Apart from more active and stable catalysts, the development of enantioselective catalysts and of continuous processes are likely to be the next goals. 

The use of ecologically harmless SCCO2 as solvent and substrate in chemical reactions is a particularly intriguing prospect. Increased governmental and environmental restrictions on solvent emission make this supercritical fluid more and more attractive as a reaction medium because it can be easily separated from the product and recycled more efficiently than conventional liquid solvents. The special properties (miscibility, transport properties, etc.) of sc CO2 require a development of suitably adjusted catalysts. A simple transformation of catalyst properties from conventional solvents to SCCO2 will mostly fail, and will not lead to higher catalytic efficiency. Supported catalysts could perhaps play a particular role in this field as the possibility of product extraction by depressurization of the supercritical phase and subsequent compression of the CO2 (solvent/substrate) should permit the development of a profitable continuous process. 

Despite these efforts, the cost of palladium-alloy membranes is still perceived by many to be prohibitive. However, even without a judicious reclamation and recycling program, the cost of palladium in current state-of-the-art, thin supported membranes is a small fraction of the total cost of the associated reformer and fuel cell system. With further development work from the private sector and government labs33 (supported by the Department of Energy), the prospect for volume commercial products is encouraging. 

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