Tag Archives: Photosynthesis

Scientists have created a device that produces plastic from CO2 and sunlight energy from artificial photosynthesis.

Posted on November 26, 2017 by | 1 comment

Scientists from the National University of Singapore (NUS) have created a device that imitates natural photosynthesis and uses a greenhouse gas to make ethylene gas (a primary ingredient in polyethylene, the most common plastic in the world). This method requires only sunlight, water and CO2,making for a non-destructive and eco-friendly alternative to current ethylene production methods.

Polyethylene demand and production challenges

Polyethylene is in extremely high demand for its use in everyday objects. Humans produce 10`s of millions of tonnes of polyethylene each year, and demand is increasing in correlation with the exponentially growing population. According to a study done from the Freedonia Group, demand for polyethylene will surpass 220 million tonnes by 2020.

Current methods of ethylene production require the burning of fossil fuels, which pollute the atmosphere with greenhouse gases. Producing one pound of ethylene returns two pounds of carbon dioxide [3]. Additionally, fossil fuels are a limited resource, straining its availability. These challenges have driven Professor Jason Yeo Boon Siang and his team in finding a renewable and environmentally-friendly way of producing ethylene

Artificial photosynthesis and ethylene production

Two photosynthetic by-products are crucial to our existence: Sugars and oxygen. These products make photosynthesis important to humans. Photosynthesis is defined as  the chemical process in which plants use the energy of the sun to make carbohydrates from carbon dioxide and water. This is nature`s convenient method of handling carbon dioxide in the atmosphere.

In 2015, the scientific team created a copper catalyst that could produce ethylene in the presence of water and carbon dioxide when stimulated with electricity. They then combined this copper catalyst with an artificial photosynthesis system to create a device that could create ethylene by using solar energy in place of electricity. This prototype, if up-scaled on an industrial level, could revolutionize the current eco-harming methods of polyethylene production, and could potentially decrease CO2 concentrations in the atmosphere for future years to come. Not only does this new device produce ethylene with a clean and renewable energy source, it also cleans the air we breath!

Doctor Yeo said: “Carbon capture is a key step in fighting human-driven climate change. There has been a steady increase in the atmospheric concentration of carbon dioxide, because the rate of carbon dioxide emissions exceeds that of carbon capture. This has been attributed as a major cause of global warming which leads to undesirable environmental changes. Our device not only employs a completely renewable energy source, but also converts carbon dioxide, a greenhouse gas into something useful. This could potentially close the carbon cycle.”

The future of sustainable plastic production:

 

Source:

  1. National University of Singapore. “Scientists develop artificial photosynthesis device fo greener ethylene production.” ScienceDaily. ScienceDaily, 24 November 2017      <www.sciencedaily.com/releases/2017/11/171124084755.htm>.
  2. Peng, Y.; Wu, T.; Sun, L.; Nsanzimana, J. M. V.; Fisher, A. C.; Wang, X. ACS Applied Materials & Interfaces 2017, 9 (38), 32782–32789.
  3. Posen, I. D., Jaramillo, P., Landis, A. E., & Griffin, W. M. (2017). Greenhouse gas mitigation for U.S. plastics production: energy first, feedstocks later. Environmental Research Letters, 12(3), 034024. doi:10.1088/1748-9326/aa60a7

-Sina Alavi

1 Comment

Posted in Economy, Manufacturing, News, Synthesis

Tagged , , , , ,

Is Quantum Cliché?

Posted on November 13, 2017 by | Leave a comment

The word “quantum” is often over-used, sometimes in contexts where it is not remotely applicable, much to the annoyance of scientists. However, quantum mechanics, the often misunderstood field of physics relating to the motion and properties of particles on nanometre scales, actually does have more effects on our day-to-day life than many people realize, and more of these effects continue to be discovered. Technological innovations which were made possible by the study of quantum physics are the most commonly cited examples of quantum mechanics in day-to-day life, but recent research is leading scientists to believe that quantum phenomena may be at play in nature as well.

Recent studies have shown evidence of a phenomenon unique to quantum physics, called coherence, being at play in the process of photosynthesis. Coherence is a property of waves which is observed in quantum mechanical particles, because one of the key results of quantum mechanics is the fact that particles are not discrete, but actually waves. Waves can be in phase or out of phase, depending on how their troughs and peaks line up with each other. If they line up in a consistent pattern, then two waves are said to be coherent. In quantum mechanics, two particles being in a coherent state means that the wave functions that describe them are coherent with one another. Usually systems tend towards decoherence, because particles’ wave functions become less well-defined as they interact with the environment, making them in phase with each other in some places, and out of phase in others.

These figures demonstrate the difference between coherent and incoherent waves. The coherent waves above add to form a well-defined wave, while those below add to form a wave with randomly varying amplitude and phase
Credit: Wikimedia Commons

The classic Schrodinger’s cat thought experiment, in which a cat is both alive and dead at once, is one of the most well-known examples of quantum mechanics. It is made possible because the cat exists in a superposition of different states, which are able to be added together because they are coherent.

An illustration of the structure of photosystem II, as found in cyanobacteria
Credit: Wikimedia Commons

When plants convert light from the sun into energy, they initially use the energy from incoming photons to move electrons, in what is called a charge transfer. The process of charge transfer is exceptionally efficient, and without this efficiency, photosynthesis as we know it would not be possible. In a recent paper in Nature, researchers described their analysis of a reaction centre where charge transfer occurs, called photosystem II, and detailed how their results demonstrate that the high efficiency of charge transfer in photosynthetic processes is due to quantum coherence. The researchers obtained photosystem II protein complexes from spinach leaves, and analyzed the quantum states of these complicated species using lasers. They observed evidence of quantum coherence during charge transfer and proposed that “this coherence allows the sampling of the energy landscape (or switching between pathways) until the system finds the optimal route towards charge separation.” Clearly, this kind of “sampling of the energy landscape” could not be predicted without knowledge of the strange phenomena which are described by quantum mechanics.

This research demonstrates that the word “quantum” should not only be conjured up when thinking about the future of computers, and peddlers of pseudo-scientific products, but also when out for walks in the forest, or biting into a crisp apple, both of which might not be possible without the quantum phenomena that allow photosynthesis to be a viable process.

Leave a comment

Posted in Admin

Tagged , , , , ,

Beating Plants at Its Own Game

Posted on October 16, 2017 by | 2 comments

Photosynthesis, the ability to convert sunlight into energy, has always been known as the trademark for plants. With the treat of climate change and a shift away from fossil fuel energy, this often overlooked ability seem to be a perfect solution.

Photosynthesis in Nature (Sourced: Wiki Commons)

A group of researchers at UCLA has beaten plants at its own game of photosynthesis. They developed an artificial photosynthesis system that is more efficient that its nature counterpart. Photosynthesis is the simple process of using sunlight energy to convert carbon dioxide (CO2) and water into chemical energy. In nature, the process of photosynthesis is not very efficient as it only convert approximately 1% of solar energy into usable chemical energy. The research utilized a hybrid system which was reported to be 10 times more efficient than plants.

Plants’ photosynthesis efficiency is mainly limited by the light absorbing pigments. However, solar panels that absorbs light much better has already been invented. The researchers designed a nano-wire coated with bacteria which collects sunlight similar to a solar panel and allows the bacteria to use the energy to convert carbon dioxide and water into liquid fuel. The difficulty of previous attempts at imitating photosynthesis is the deaths of bacteria responsible for the conversion of light into chemical energy caused by a bacteria killing oxygen by-product. They developed a new catalyst to kick start the chemical reactions by the bacteria without killing them.

There is a video explaining the nano-wire research below:

YouTube Preview Image

This new system is estimated to be able to recycle carbon dioxide in 85,000 liters of air into fuel. The research also found by using a different bacteria, nitrogen gas can be converted into ammonia, a common ingredient in fertilizers. This research can change our approach on how to solve the energy crisis due to climate change.

Who could have known that such little plants could hold the key to solve such a big problem?

Written By: Harvey Wu

2 Comments

Tagged , , , , , , ,