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| Regel 1: |
Regel 1: |
| '''Exam questions Sustainable Chemistry II (2019-2020)'''
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| (1) What is the definition of “sustainable development”? Why is the term “sustainability” often
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| preferred over the term “sustainable development”?
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| (2) What is biomimicry? What are the main principles on which biomimicry is based? Give three
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| examples of how biomimicry can help to decrease the carbon footprint of our society.
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| (3) What are, according to the principles of green chemistry, the characteristics of an ideal organic
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| synthesis procedure?
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| (4) How can green engineering help to enable a circular economy in the electronics industry?
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| (5) It is a paradox that precisely those persons who are very environmentally conscious and strive for a
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| rapid transition to a low-carbon economy may endanger the supply of the raw materials needed for this
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| transition because of their protests against the opening of new mines. Discuss this paradox and provide
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| a possible solution for this problem.
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| (6) One often reads in the popular press that metal recycling via urban mining can replace the primary
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| mining of metal ores. Is this a realistic approach and why (not)?
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| (7) The 1972 report of the Club of Rome (published in the book " The Limits to growth: a global
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| challenge ") was very negative about the future availability of raw materials. For example, it was
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| predicted that by the year 2000 the copper resources would be largely depleted. However, the
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| predictions about resource scarcity all proved to be wrong. Why were the authors of this report
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| completely wrong with their predictions?
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| (8) Show that the criticality of raw materials has little to do with the availability of these raw materials in
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| the earth's crust. What are the disadvantages of using a list of critical raw materials as a policy
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| instrument?
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| (9) Why does is make sense, from the point of view of sustainability, to convince materials engineers to
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| develop new materials with an as low as possible content of by-product metals?
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| (10) Platinum-group metals (PGMs) and rare-earth elements (REEs) may be considered as “coupled
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| elements”. (a) What does the term “coupled elements” mean? (b) What is the difference between
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| coupled elements and by-product elements?
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| (11) How can rare-earth elements help to reduce the reduction CO2 emission from burning of fossil
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| fuels?
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| (12) What are the options for end-of-life product in (a) a linear economy and (b) a circular economy?
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| (13) What are the benefits and limitations of recycling?
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| (14) What are the different steps in a generic flow sheet for recycling of materials? What are the least
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| and most efficient steps in this flow sheet? Why?
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| (15) (a) Why does it not make sense, from the point of view of energy consumption, to try get a
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| recycling rate of 100% for metals from end-of-life products? (b) Why have iron, copper, aluminium,
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| lead, platinum-group metals, gold and silver high recycling rates (>50%), whereas the recycling rates for
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| the rare-earth elements are very low (<5%)?
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| (16) Why do have many metals very low recycling rates, although recycling is technologically feasible?
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| How can legislative initiatives help to increase recycling rates?
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| (17) What are the differences between metal-centric recycling and product-centric recycling? Which of
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| the two approaches is the preferred one and why?
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| (18) It is a general trend in the history of technology that materials are becoming more and more
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| complex in terms of the total number of chemical elements used in materials. Is this a positive trend in
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| terms of sustainability? Why (not)? Discuss this statement.
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| (19) The process flowsheet of steel-making from iron ores is quite different from that for recycling of
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| steel scrap. Discuss the main differences. Why are different processes used for steel-making from iron
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| ores and from steel scrap?
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| (20) How can platinum-group metals (PGMs) be recycled from automobile catalysts?
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| (21) What rare-earth elements are present in fluorescent lamp phosphor waste and how can these be
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| recycled?
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| (22) What is enhanced landfill mining (ELFM)? What are the differences between urban solid waste
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| landfills and industrial residue monolandfills? Why is it so difficult to make an economic success story of
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| ELFM?
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| (23) What different waste-to-energy technologies can be used in enhanced landfill mining (ELFM)?
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| (24) The process residues of the metallurgical industry could be a valuable source of critical metals and
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| base metals. However, it is recommended to use a product-centric approach rather than a metal-centric
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| approach for valorization of these residues. Why? What are the most interesting industrial residues for
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| metal recovery? How are they formed and what metals are present at high concentrations in these
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| residues?
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| (25) Compare the advantages and disadvantages of homogeneous and heterogeneous catalysts.
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| (26) What is fluid cracking catalysis (FCC) and what types of catalyst is used for this process?
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| (27) Which pollutants are emitted by incomplete combustion of hydrocarbon fuel? What are the health
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| and environmental issues related to these pollutants?
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| (28) What is the function of a catalytic converter in cars? Describe a catalytic converter from a materials
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| point of view (geometry, structure, chemical composition, function of materials).
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| (29) Describe the working principle of a three-way catalyst for exhaust after-treatment of spark-ignition
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| engines operated under stoichiometric conditions.
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| (30) What is the role of oxygen storage by ceria in a three-way catalyst? Why is ceria able to store and
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| release oxygen?
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| (31) What is the role of precious metals in three-way catalysis?
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| (32) Why is diesel catalytic exhaust after-treatment more complicated to gasoline engines? What
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| catalysts are present in the exhaust after-treatment system of a diesel vehicle?
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| (33) Discuss selective catalytic reduction (SCR) with ammonia in the exhaust after-treatment system of a
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| diesel vehicle.
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| (34) Discuss the working principle of Li-ion batteries. What are the advantages and disadvantage of the
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| different types of cathode materials presently used in these batteries?
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| (35) Discuss the working principle of redox flow batteries. Why could this type of batteries be of
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| importance in the future to secure the electricity supply in Belgium?
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| (36) Discuss the advantages and disadvantages of the following types of solar cells: (1) monocrystalline
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| silicon solar cells, (2) polycrystalline silicon solar cells, (3) thin-film solar cells.
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