2019 has been declared by UNESCO as the Year of the Periodic Table. To celebrate, we are releasing a series of blogs about our favourite elements and their importance to the chemical industry. Today’s blog focuses on sodium and its role in the next series of innovative nuclear energy systems.
Sodium; the sixth most abundant element on the planet is being considered as a crucial part of nuclear reactors. Implementing new safety levels in reactors is crucial as governments are looking for environmentally friendly, risk-free and financially viable reactors. Therefore, ensuring new safety levels is a main challenge that is being tackled by many industries and projects.
In the wake of Fukushima, several European nations and a number of U.S plants have shut down and switched off their ageing reactors in order to eliminate risk and safety hazards.
The sodium- cooled fast reactor (SFR), a concept pioneered in the 1950s in the U.S, is one of the nuclear reactors developed to operate at higher temperatures than today’s reactors and seems to be the viable nuclear reactor model. The SFR’s main advantage is that it can burn unwanted byproducts including uranium, reducing the need for storage. In the long run, this is deemed cost-competitive as it can produce power without having to use new natural uranium.
Nuclear reactor. Source: Hallowhalls
However, using sodium also presents challenges. When sodium comes into contact with air, it burns and when it is mixed with water, it is explosive. To prevent sodium from mixing with water, nitrogen - driven turbines are in the process of being designed as a solution to this problem.
A European Horizon 2020 Project, ESFR-SMART project (European Sodium Fast Reactor Safety Measures Assessment and Research Tools), launched in September 2017, aims to improve the safety of Generation-IV Sodium Fast Reactors (SFR). This project hopes to prove the safety of new reactors and secure its future role in Europe. The new reactor is designed to be able to reprocess its own waste, act more reliably in operation, more environmentally friendly and more affordable. It is hoped that this reactor will be considered as one of the SFR options by Generation IV International Forum (GIF), who are focused on finding new reactors with safety, reliability and sustainability as just some of their main priorities.
European Horizon. Source: artjazz
Globally, the SFR is deemed an attractive energy source, and developments are ongoing, endeavouring to meet the future energy demands in a cost-competitive way.
2019 has been declared by UNESCO as the Year of the Periodic Table. To celebrate, we are releasing a series of blogs about our favourite elements and their importance to the chemical industry. Today’s blog is about iodine and some of the exciting reactions it can do!
Iodine & Aluminium
Reaction between iodine and aluminum. These two components were mixed together, followed by a few drops of hot water. Source: FaceOfChemistry
Reactions between iodine and group 2 metals generally produce a metal iodide. The reaction that occurs is:
2Al(s) + 3I2(s) → Al2I6(s)
Freshly prepared aluminium iodide reacts vigorously with water, particularly if its hot, releasing fumes of hydrogen iodide. The purple colour is given by residual iodine vapours.
Iodine & Zinc
Zinc and iodine react similarly to aluminium and iodine. Source: koen2all
Zinc is another metal, and when it reacts with iodine it too forms a salt – zinc iodide. The reaction is as follows:
Zn + I2→ ZnI2
The reaction is highly exothermic, so we see sublimation of some of the iodide and purple vapours, as with the aluminium reaction. Zinc iodide has uses in industrial radiography and electron microscopy.
Iodine & Sodium
Iodine reacting with molten sodium gives an explosive reaction that resembles fireworks. Source: Bunsen Burns
As with the other two metals, sodium reacts violently with iodine, producing clouds of purple sublimated iodine vapour and sodium iodide. The reaction proceeds as follows:
Na + I2→ 2NaI
Sodium iodide is used as a food supplement and reactant in organic chemistry.
Iodine Clock reaction
The iodine clock reaction – a classic chemical clock used to study kinetics. Source: koen2all
The reaction starts by adding a solution of potassium iodide, sodium thiosuphate and starch to a mixture of hydrogen peroxide and sulphuric acid. A set of two reactions then occur.
First, in a slow reaction, iodine is produced:
H2O2 + 2I− + 2H+ → I2 + 2H2O
This is followed by a second fast reaction, where iodine is converted to iodide by the thiosulphate ion:
2S2O32− + I2 → S4O62− + 2I−
The reaction changes colour to a dark blue or black.
The elephant’s toothpaste reaction is a favourite for chemistry outreach events. Source: koen2all
In this fun reaction, hydrogen peroxide is decomposed into hydrogen and oxygen, and catalysed by potassium iodide. When this reaction is mixed with washing-up liquid, the oxygen and hydrogen gas that is produced creates bubbles and the ‘elephant’s toothpaste’ effect.
There are lot’s of fun reactions to be done with iodine and the other halogens (fluorine, bromine, chlorine).
Iodine’s sublimation to a bright purple vapour makes it’s reactions visually pleasing, and great fun for outreach events and science classes.