Category Archives: frontiers of chemistry

A Solution for Climate Change?

CO2 concentrations over the last 400,000 years

A graph showing the rise and fall of CO2 concentration in the atmosphere, recorded over thousands of years. The magnified area indicates the dramatic increase of CO2 concentration during the Industrial Revolution. (c) Robert A. Rohde, used under Creative Commons Attribution-Share Alike 3.0 Unported

There is no doubt that climate change is real, dangerous, and occurring at an alarming rate that is unprecedented in the past 1,300 years. A major of the cause of this change is due to carbon dioxide gas, the product of burning fossil fuels for energy to run our cars, factories, for the production of electricity, and more. Carbon dioxide, one of many greenhouse gas, naturally acts as sort of a “blanket”, absorbing and emitting infrared radiation from the earth, causing the atmosphere to warm up, which known as the greenhouse effect.

A diagram illustrating the greenhouse effect.

A diagram illustrating the greenhouse effect. (c) US EPA used under public domain

Initiatives to reduce carbon dioxide emissions have already been implemented in our everyday lives, for example a simple thing like biking or taking public transit can reduce the amount of carbon dioxide emitted by automobiles. However, new carbon dioxide emissions data shows that our  efforts are not paying off. Every year, it is estimated that 38 billion tons of unnecessary carbon dioxide is released into the atmosphere. Even as you read this article 2.4 million pounds of this greenhouse gas is released into the atmosphere per second!

It seems that our efforts to reduce carbon dioxide emissions have failed and each year we can see a steady increase in emissions. Our economic and societal infrastructure has made us incredibly dependent on burni

Simple illustration of the conversion of CO2 into CO using silicon. (c) Chenxi Qian, used under Creative Commons Attribution 4.0 International License.

ng fossil fuels for energy. Perhaps the real solution lies in taking the excess carbon dioxide gas and converting it back into usable energy.

Recently, scientists from the University of Toronto believe to have discovered a method of converting carbon dioxide gas into energy-rich fuel. Professor Geoffrey Ozin and his team have developed a method using silicon, naturally found in sand, to efficiently and selectively convert gaseous carbon dioxide to carbon monoxide without any harmful emissions. Carbon monoxide can then be converted into hydrocarbon fuels such as petrol through a series of chemical reactions known as the Fischer-Tropsch process.

“A chemistry solution to climate change requires a material that is a highly active and selective catalyst to enable the conversion of CO₂ to fuel. It also needs to be made of elements that are low cost, non-toxic and readily available,” said Dr. Ozin.

Right now they are working on ways to increase the activity, enhance the scale, and boost the rate of production. Hopefully in the near future, there will be even more research dedicated to converting other greenhouse gases, not just carbon dioxide, into reusable energy, and then maybe we will be able to resolve the issues that have been caused by the detrimental amounts of greenhouse gases in our atmosphere.

– Charlie Wei

Waste not, want not!

Value Chain Management International published a report stating that food waste costs Canada $31 billion a year. The report found food waste accumulating in restaurants, retail stores, domestic homes, restaurants, hotels, food processing factories, farms, and many more. Unfortunately the report says the amount of food wasted can actually increase the cost of food by 10 percent or more! Peers, I don’t know about you, but as a full time student, passionate eater, and no-time employee, I am not interested in forking up any percent more money to feed my persistent stomach, or else my face will look just like this baby.

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Image Credits: Elizabeth Delisi elizabethdelisi.blogspot.com

Luckily for us, Huaichen Zhang et al. at the Eindhoven University of Technology in the Netherlands, are developing a possible method to use sugar alcohols to store solar, and wind energy. The study uses naturally occurring xylitol and erythritol (molecular structures shown below). Both of which are often used as natural sweeteners. They investigated nanoscale heat transfer (NHT) across carbon structures dissolved in these compounds. The researchers used several sizes of carbon nanotubes (cylindrical forms of carbon depicted in the image below) submerged in the sugar alcohols, and employed various analytical techniques, and computer simulations, to observe the movements of the molecules and quantify the thermal conductance across them.

Structure of Xylitol. Image Credits: Century Stone Dental http://www.centurystonedental.com/blog/health-benefits-of-xylitol/

Structure of Erythritol. Image Credits: Wikipedia https://en.wikipedia.org/wiki/Erythritol

Structure of Erythritol. Image Credits: Wikipedia https://en.wikipedia.org/wiki/Erythritol

Carbon Nanotube. Image Credits: Gaia Technologies http://www.gaia3d.co.uk/3d-models/3d-chemistry/carbon-nanotube/Nanotube

Carbon Nanotube. Image Credits: Gaia Technologies http://www.gaia3d.co.uk/3d-models/3d-chemistry/carbon-nanotube/Nanotube

Most people are familiar with macroscale heat transfer: conduction, radiation, and convection. NHT on the other hand, is at a much smaller scale; it deals with heat transfer across atoms and molecules, as opposed to larger macroscopic objects. To put it into perspective, nano typically means 1 x 10-9.

NHT can be applied to modern technology. This includes improving the efficiency of energy conversion and storage. Alan McGaughey, a professor at Carnegie University, studies NHT, and thermal conductivity. He shows the importance of understanding heat transfer at the atomic level in order to advance technology and science. For example, further research of NHT could improve the energy conversion of light to electricity in LEDs.

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In conclusion of the Netherlands study, they found that smaller diameters of the nanotubes led to less heat transfer within the mixture. However, higher density combinations of the mixtures led to more heat transfer!

If Zhang, et al. can investigate the use of carbon and sugar alcohols in NHT to improve thermal storage, there may be hope for the food waste problem. The sugars and materials found in food waste could potentially be the key to better thermal energy storage, and therefore it wouldn’t really be considered waste after all!

This research contributes to a stronger understanding of the conductivity of carbon nanotubes, significance of nanoscale heat transfer, possible applications of these understandings, and most importantly brings forward a way to use all of the waste our species is contributing to the world!

Hooray for science!

– Nicole Yipp

References:

  1. Huaichen Zhang, Camilo C. M. Rindt, David M. J. Smeulders, Silvia V. Nedea. Nanoscale Heat Transfer in Carbon Nanotubes – Sugar Alcohol Composite as Heat Storage Materials. The Journal of Physical Chemistry C, 2016; DOI:10.1021/acs.jpcc.6b05466
  1. Luo, T.; Chen, G. Physical Chemistry Chemical Physics 2013, 15 (10), 3389.
  2. Chen, G.; Borca-Tasciuc, D.; Yang, R. G. Encyclopedia of Nanoscience and Nanotechnology 2004, 7, 429–459
  1. American Chemical Society (ACS). “Food waste could store solar, wind energy.” ScienceDaily. www.sciencedaily.com/releases/2016/09/160915133240.htm (accessed October 3, 2016)