Category Archives: Manufacturing

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

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A New Nonstick Coating makes life easier

Posted on November 13, 2017 by | 2 comments

Have you ever attempted to scoop out the remaining honey with fingers in a container? Have you ever squeezed really hard to get the last bit of a toothpaste? Is the little bit clingy glue in the bottom of the bottle really annoyed you when you try to use it?

A company called LiquiGlide discovered a new nonstick coating can let the above problems go away. The basic idea is to use this special coating to make the inside of container slippery so that the liquid will slide back into the bottom instead of sticking to the lid and drying there. In addition, a test by Consumer Reports in 2009 indicated that much of what we buy never makes it out of the container and is instead thrown away — up to a quarter of skin lotion, 16 percent of laundry detergent and 15 percent of condiments like mustard and ketchup. Therefore, If this material is widely used in daily life, we can save resources and reduce waste.  Bingham plastics is the most common material that is used in traditional container manufacturing. Bingham plastic is named after Eugene Bingham, a chemist who proposed the mathematical properties. This material is highly viscous and does not flow without a strong push.

This picture shows the average waste and the differences between new nonstick coatings and traditional coatings. (source)

The key to success this technology is to find a material that has superhydrophobic surfaces. Superhydrophobic surfaces are non-wettable surfaces with high water contact angles and facile sliding of drops. The superhydrophobic surface is rough under a microscope. Water rolls up into balls, sitting on the tips of the rough surface, but mostly on air trapped between the droplet and the rough surface. The droplets roll off easily. In this new material,  the lubricant binds more strongly to the textured surface than to the liquid, and that allows the liquid to slide on a layer of lubricant instead of being pinned against the surface, and the textured surface keeps the lubricant from slipping out. However, finding a proper material is not easy. If the microscopic roughness is damaged, water will flow in and displace the pockets of air, then stick to the no-longer-slippery surface. Since air can dissolve into the water if superhydrophobic surfaces are submerged in water for long periods, it will become rough. As a result, detergents or lotions will stick on the wall of containers.

This picture describes how superhydrophobic surface works in this new material. (source) 

In the future, the company wants to explore further on the industrial applications including coatings for petroleum storage tanks and pipelines. If these applications can succeed, less energy needed to push materials through the pipes,  fewer chemicals required cleaning the pipes.

 

 

 

 

 

Written by Nancy Ma

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Ferrocene: A powerful organometallic compound that has various medicinal applications

Posted on October 30, 2017 by | 1 comment

Research in medicinal chemistry has been booming in the last few years due to important discoveries made by fellow scientists. Ferrocene which is one of the most famous organometallic structures discovered in the early 1900’s can open many routes in cancer research. The discovery of the first sandwich complex opened a new area of research and since then many similar structures have been synthesized. Wilkinson and Fischer received a Nobel prize in chemistry for their remarkable work in developing sandwich structures using transition metals. A sandwich complex is defined as a metal center connected to aromatic rings. When ferrocene was discovered, its medicinal applications were not known. Recently, Ferrocene and its derivatives have found their way in medicinal chemistry as anti-cancer and HIV agents.

Figure 1: The structure of Ferrocene consisting of an iron metal centered around two aromatic rings. The name sandwich complex comes from the fact that the metal is sandwiched between two molecules.

In order to understand the mechanism behind ferrocene acting as an anti-cancer agent, basic understanding of anti-cancer agents is required.  There is an enzyme in the body known as Topoisomerase that keeps the topology of DNA by unwinding the DNA for replication. Tumour cells increase the activity of topoisomerase; thus anti-tumor drugs act by lowering the activity of topoisomerase. Ferrocenium ions get reduced in the cell generating a hydroxyl radical. These radicals are responsible for biological damage in cancer cells. The ferrocenium species target specifically a protein complex that binds to a specific region of DNA. The above mechanism helps in inhibiting the activity of cancerous cells. Damaging the tumor cells responsible for increasing topoisomerase activity helps regulate the activity of DNA.

Figure 2: A detailed mechanism of how Ferrocene and its derivatives get reduced in the cell causing cancerous cells to die

Ferrocene derivatives are also used in regulating HIV virus which is responsible for AIDS. According to recent studies, 75,500 Canadians were living with HIV by the end 2014. The number of Canadians affected by HIV has increased dramatically in the last few years and many scientists are trying to find therapeutic agents that can target HIV. The same enzyme mentioned above known as Topoisomerase is also involved in HIV. Researchers have shown that topoisomerase is involved in HIV replication cycle. Viruses have the tendency to use the cell machinery to replicate and survive inside the body. Ferrocene derivatives are very effective in inhibiting the activity of topoisomerase involved in HIV replication. Some drugs containing ferrocene gave promising results as Anti-HIV agents. These compounds are thought to inhibit the synthesis of viral DNA.

Figure 3: Some common Ferrocene compounds and their use in medicinal chemistry

In Conclusion, organometallic compounds have unique properties that allow them to have wide applications in medicinal chemistry. Attaching ferrocene and its derivatives to biological drugs will serve in increasing the efficiency of drugs. The possibility of using ferrocene in medicinal applications are endless. Hopefully, this powerful class of compounds could find its way to market shelves soon.

By: Tarek El Sayed

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Secrets in Firefly

Posted on October 30, 2017 by | 1 comment

Have you ever seen fireflies in your childhood? It’s hard to see them now, but I am still very interested in them.

Photo of firefly.

Why do fireflies shine?

The scientists found that the bioluminescence of the firefly’s abdomen has a small aperture of the luminescent layer. This luminous layer contains thousands of light emitting cells. In the light emitting cell, it contains two kinds of chemicals, one is called fluorescein, another kind is called luciferase. Fluorescein can react with oxygen in the air, release energy in form of photons and emit fluorescence in the catalysis of luciferase. In specific, magnesium and ATP combine with luciferase and the protein luciferin. This combination creates a very excited molecule. When oxygen is introduced into the mix, the excited molecule goes from excited state back to a stable state. This procedure releases energy and creates light. Therefore, firefly luminescence is caused by chemical reactions.

Specific bioluminescence reaction in fireflies.

Why do fireflies shine off and on？

The mechanism that turns on and off this light show is still the topic of some debate. The prevailing theory revolves around the firefly’s ability to control oxygen within trachea. When oxygen is abundant, the reaction is intense and the light is strong; When the oxygen is not sufficient, the reaction is slow, the light will be weak or even bleak. There is a high-energy compound called adenosine triphosphate (ATP) in fireflies, which, when the light is weak, more ATP will be released by Mitochondria (the organelle that controls ATP production), and interact with fluorescein, so fireflies can glow again.

Do fireflies burn themselves?

The lighting reaction released almost all the energy in form of light, only a few in the form of heat release, so the fireflies light belongs to cold light. Therefore, fireflies won’t burn themselves due to overheating. Fireflies are more than 95% efficient in making this cold light.

Fireflies and bionics

Firefly has many beautiful fluorescent colours, like light green, light red and pale blue. The difference in colours are highly related to the type of fluorescence in the body. According to this feature, scientists have developed many applications based on the luminescence mechanism of fireflies. In medical science, scientists extract fluorescein from fireflies and use it in the study of cancer cells. By observing the glow of fluorescein placed in cells, they are able to judge the growing speed and growing environment of cancer. In industry, water pollution can be monitored with the help of fluorescein. The luminescence mechanism can be used in more area, because it is very simple and effective. What’s more, there are already a considerable amount of applications of cold light source, such as the flashlight for underwater operation. Cold light source can greatly improve the efficiency of converting chemical energy into light energy, so it can be developed further and applied to other aspects in our life.

Fluorescence microscopy images of sun flares pathology in a blood cell showing the affected areas in red.

-Olivia Yang-

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BPA-free Doesn’t Mean Estrogenic-free

Posted on September 25, 2017 by | 2 comments

Attribution: Flickr Commons

Before the 1990’s, when researchers began publishing papers on the harmful health effects of Bisphenol A (BPA), hard plastic polycarbonate consumer products were mostly made with the chemical monomer. Scientists uncovered that BPA, in similar structure to the estrogen, estradiol, interacts with estrogen receptors in the body, disrupting the endocrine system. This estrogenic activity can cause infertility, heart disease, cancer, neurobehavioral deficits, and more. After public demand, numerous countries began banning BPA, mainly in food and drink containers and baby products.

Estradiol (Top) and Bisphenol A (Bottom). Attribution: Wikimedia Commons and Wikimedia Commons.

Flash forward to now and our water bottles say “BPA-free”; however, this gives us a false sense of safety for, while our water bottles are free of Bisphenol A, the alternative resins used by plastic manufacturers are similar in structure and, as research shows, in negative health effects. Chemicals such as Bisphenol S (BPS) and Bisphenol F (BPF) are used as BPA alternatives in the production of PC plastic bottles and their chemical structures appear just, if not more, like estradiol than BPA. 

Bisphenol F (Top) and Bisphenol S (Bottom). Attribution: Wikimedia Commons and Wikimedia Commons.

A study published in Environment Canada found BPA-free consumer water bottles that leach BPA-like chemicals, causing the same effects to the endocrine system. The Austin, Texas private lab, CertiChem, measured the estrogenic activity of various plastic consumer bottles including black and blue CamelBak, blue and green Nalgene, Topaz, and Zeonor reusable plastic bottles. By exposing breast cancer cells, that multiply when their estrogen receptors activate in the presence of estrogen-like chemicals, to the plastic water bottles, and stressing the bottles using UV light, they determined whether these bottles were leaching estrogenic activity such as that of BPS and BPF. Their study confirmed that CamelBak and Nalgene bottles excreted Estrogenic chemicals, while Topaz and Zeonor reusable bottles remained intact even during stressed conditions.

So, if this news is as alarmingly shocking to you as it was for me and you are on the lookout for another water bottle, CertiChem‘s paper suggests that purchasing Topaz or Zeonor products is a better choice than Nalgene and CamelBak; of course, if you remain unsure, non-plastic stainless steel bottles may be the best choice for you. I just bought one at Manna.

For more information, watch the following video.

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-Lori Waugh

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Biodegradable Plastic: The New Potential Waste Management Solution

Posted on September 24, 2017 by | 1 comment

Production of plastic has increased from 0.5 million tonnes in 1950 to 260 million tonnes in 2007. It is versatile, lightweight, flexible, moisture resistant and relatively inexpensive. Their attractive qualities lead us, around the world, to an over-consumption of plastic products. However, conventional plastics, which make up 60-80 percent of marine litter from the poles to the equator, are durable and very slow to degrade. They are harmful to marine animals as they release toxic additives including flame retardants, antimicrobials and plasticizers into the marine environment during degradation. Use of a biodegradable polymer that degrades more quickly than conventional plastics may present a solution to the problem.

Mouth of the Los Angeles River, Long Beach, California. (Photo source: ©© Bill McDonald, Algalita Foundation / Heal The Bay)

During April 2008 – March 2009, researchers from Marine Biology and Ecology Research Centre of University of Plymouth investigated breakdown of four types of plastics in the marine environment, including two different oxo-biodegradable formulations trademarked as TDPATM, a biodegradable bag manufactured using GM-free corn starch, vegetable oils and compostable polyesters, and a standard polyethylene bag produced from 33% recycled materials.

The scientists fastened 20 wooden sample holders to a beam attached to a floating pontoon at Queens Anne Battery Marina, Coxside Plymouth, Devon and examined degradation at 4, 8, 16, 24, and 40 weeks. After 24 weeks of exposure, the compostable polyester samples lost 100% of their surface area. However, the other materials lost only approximately 2% of their surface area over 40 weeks exposure. Fouling by marine organisms reduced the sunlight reaching the surfaces of the standard polyethylene, TDPATM 1 and 2 samples, which resulted in much slower degradation.

Plastics in the Ocean Affecting Marine Life

Plastic bags are especially harmful to marine animals since many animals confuse the plastic litter in the ocean with food. Ingestion of plastic debris may present a threat as chemicals including phthalates, polychlorinated biphenyls and organochlorine pesticides on plastic fragments may present a toxicological hazard.

One in three leatherback sea turtles has plastic in its stomach, based on a study of over 370 autopsies. (Photo: Laura Beans)

“A large number of marine species is known to be harmed and/or killed by plastic debris… One possibility to mitigate the problem is the development and use of biodegradable and photodegradable plastics.” (Derraik, 2002)

Biodegradable polymers offer potential waste management solutions. However, there are still limitations and ethical issues about their application.

-Jennifer Liu-

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