Precious metals, especially platinum, are important catalytic materials for many chemical reactions. For example, platinum is used in some fuel cells; however, broad commercialization of such fuel-cell technology is hampered by the fact that platinum is rare and thus far too expensive.
Growing demand is making it necessary to develop efficient and environmentally friendly processes for recycling platinum. Jing-Fang Huang and Hao-Yuan Chen at the National Chung Hsing University in Taiwan have now introduced a new approach in the journal Angewandte Chemie. Their method is based on the dissolution of the metal in an ionic liquid.
Recycling platinum is a difficult, complicated process. The first step is the dissolution of the used platinum. Because platinum is a very special precious metal, this isn’t so easy. The solvents used for this are usually highly corrosive aqua regia, a mixture of nitric and hydrochloric acids, or a highly oxidizing mixture of sulfuric acid and hydrogen peroxide known as piranha. There are also electrochemical recycling processes, but these mostly require highly toxic electrolytes or corrosive media, or they release toxic gases. They also suffer from insufficient current densities and passivation of the electrodes.
Huang and Chen have now developed a novel process that avoids all of these disadvantages. In this procedure, platinum is electrochemically dissolved in a mixture of zinc chloride and a special ionic liquid. An ionic liquid is an organic salt that is in a melted state at temperatures below 100 °C. Ionic liquids are considered environmentally friendly solvents because they have very low vapor pressures and are very thermally stable, so they do not release any toxic substances. They also have high ionic conductivity, which makes them very useful in electrochemical applications.
The used platinum is introduced in the form of an electrode, a voltage is applied, and the surrounding ionic liquid heated to about 100 °C. The platinum then dissolves surprisingly fast. The dissolved platinum can then be removed on a carrier electrode, either as the pure metal or as a zinc alloy, without prior treatment of the solution. The scientists are optimistic that this process can also be adapted for other precious metals.
Says Huang: “We are doing our best to solve the problem about the effective use of precious metals. The recycling of precious metals is a possible strategy. Even now, we do not think we have found the best process. We will continuously modify the process in order to extend its applications or look for a much better one”.
Switch-in-a-cell electrifies life
18.12.2018 | Rice University
Plant biologists identify mechanism behind transition from insect to wind pollination
18.12.2018 | University of Toronto
Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.
Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
18.12.2018 | Materials Sciences
18.12.2018 | Physics and Astronomy
18.12.2018 | Physics and Astronomy