Category Archives: Materials

A green future for ammonia

Chemists from the University of California, Berkley (UCB) have designed a new material that could reduce the energy requirements of the Haber-Bosch process. The group hopes their research, published January 11th 2023, will conserve energy and lead to a “greener” future for ammonia and fertilizer production.

Current infrastructure needed to maintain the pressure and temperature required for the Haber-Bosch process source

The Haber-Bosch process has been the main method for producing ammonia since its invention over 100 years ago. It is widely considered one of the most important scientific discoveries of the 20^th century. Yet, despite its important role producing ammonia for agricultural fertilizer, its industrial synthesis continues to be energy inefficient.

High temperatures and pressures are needed to produce ammonia which must then be extracted to be used. Conventionally, the reaction mixture is cooled from 500℃ to -20℃. This condenses the synthesized ammonia and separates it from the remaining chemicals. However, cooling the mixture while maintaining the pressure of 300 atmospheres accounts for a large proportion of the processes’ energy loss.

Benjamin Snyder, who leads the UCB research group, said it was this extraction step that his team sought to improve by “finding a material where you can capture and then release very large quantities of ammonia, ideally with a minimal input of energy”.

These requirements led the research group to create a metal-organic framework (MOF) material. The MOF had a crystal structure made from copper atoms linked to cyclohexane dicarboxylate molecules. The crystalline structure gave the material unique properties suited for its use in ammonia extraction.

Structure of the cyclohexane dicarboxylate molecule used to make the MOF source

When exposed to ammonia the material changes its structure from a rigid crystal to a loosely packed and porous polymer. The polymer form can readily store a large amount of ammonia within it which can then be released with cooling. The result is that ammonia can be extracted 195℃ above the temperature required by current methods and at half the pressure.

Not only would the MOF save energy in the extraction process but, interestingly, after releasing the ammonia “the polymer somehow weaves itself back into a three-dimensional framework” says Snyder. This mechanism, which is still being studied, allows the MOF to be used repeatably.

With the Haber-Bosch process using 1% of the world’s energy, the research done by Snyder and his group is an important step in producing a greener future for ammonia.

Enzymes – A Solution in the War Against Plastics

According to the United Nations Environment Programme, today, “about 400 million tonnes of plastic waste” is produced every year. The amount of plastic waste generated has risen significantly in a single decade compared to the last 40 years.

One of the biggest problem with plastic waste is that plastics can not breakdown in a short period of time. It can take up to 500 – 800 years for a piece of plastic to be broken down by UV radiation – light from the sun.

Plastic waste along the shoreline. Source

Researchers at the University of California, Berkeley have invented a new way to decompose polyester based plastics much quicker. Simply with heat, water, and nano-dispersed enzymes.

Dr. Ting Xu, a UC, Berkeley professor and her research group developed an enzyme that is able to eat away at the polymers in plastics. These nanoscale polymer-eating enzymes are embedded into plastics as they are being made. To prevent the enzymes from activating when not required, a random heteropolymer (RHP) coating is applied to hold the enzymes without restricting the flexibility of tensicity of the plastics.

Plastic cups made from biodegradable plastics. Source

The enzymes were wrapped around plastic resin beads. These beads were then melted and molded into usable consumer plastics. Xu likened this process to organic composting. By adding water and heat, the enzymes, the RHP polymer coating is removed and starts eating away the polymers into smaller subunits.

The research conducted by Xu and her group found that the enzymes took about a week to degrade most of the plastics. Polylactic acid (PLA) and polycaprolactone (PCL) based plastics embedded with nanoscale polymer eating enzymes are able to break down the polymer chains into small molecules, such as lactic acid.

It is clear that there is still more research needed in this field. Currently, Xu is developing other modified RHP-wrapped enzymes that can stop the degradation process at specific points in it’s degradation so that the polymers can be recycled into new plastics.

Moving forward, Xu has high hopes for the polymer eating enzymes to change the way we look at recycling and that it will start a conversation about the way humans interact with the Earth.

According to Xu, “[humans] are taking things from the earth at a faster rate than we can return them. Don’t go back to Earth to mine for these materials but mine whatever you have, and then convert it to something else.”

~ Raymond Tang

Blue Light – A Propagated Myth

Unsplash Photo by Ales Nesetril (Editorial, Technology)

Blue light from electronic devices does not damage the eyes, but it may damage your sleep.

The lie propagated is unfounded in science and was debunked. Those spreading it are misinformed and scientifically uneducated.

Light sources such as incandescence (light bulbs) and LEDs emit a broad spectrum of light, namely 380 to 700 nanometers (nm). Blue light is in the 400 – 450 nm range, carrying more energy compared to red light, which raises concern.

Our retinas regularly absorb blue light emitted by the sun, and for over 300,000 years has been the case and proven not to be damaging – otherwise, we would be blind.

In addition, device intensities are much less than the sun and are regulated by manufacturers using light filters.

According to Dr. Ramsey, a Havard Health Publishing Contributor, and Director of Ophthalmic Research at Lahey Massachusets Hospital, “many retail stores have ambient illumination twice as great…as your iPhone. [Yet] the sun yields illumination ten times greater!”

He also adds that using devices late at night mimics sunlight, restraining the production of melatonin, a sleep-inducing hormone. This stimulates your circadian clock (your body’s 24 hr sleep clock), tending to delay your sleep cycles, disrupting your sleep, and increasing drowsiness the following morning.

By stopping using electronic devices 30 minutes before bed, you can increase REM (deep-stage sleep), reduce morning drowsiness, and maintain a consistent circadian rhythm, which in itself has its own benefits.

In short, do your own research before propagating a supposed “scientific claim,” and reduce your screen time before bed.

~ Octavian Turner

A Breakthrough in Nuclear Fusion

On December 5th 2022, scientists at the Lawrence Livermore National Laboratory (LLNL) in the United States successfully created the reaction that powers the sun – nuclear fusion ignition – for the first time in human history.

Announced by the US Department of Energy on December 13th, this “historic, first-of-its-kind” achievement has excited the scientific community because of its potential as a clean energy source.

Inside the LLNL’s National Ignition Facility, where the experiment took place. Credit: LLNL

To achieve fusion ignition, the scientists had constructed “the world’s most energetic laser”, consisting of 192 laser beams, and aimed it at a small canister containing the compounds deuterium and tritium. They were able to generate 3.15 megajoules of energy from an input of 2.05 megajoules, a markup of 54%.

This result – more than 60 years after researchers first began to study fusion – proved that controlled nuclear fusion that produces more energy than it consumes is possible.

Depiction of fusion: deuterium(D) and tritium(T) fuse to form the larger Helium(He) and release energy. Credit: US Department of Energy

Nuclear fusion – the process that allows the Sun to emit vast amounts of energy in the form of light and heat – involves the joining of two atoms of a lighter element to form a heavier one, and in the process releases a lot of energy. Compared to nuclear fission, which is how nuclear power plants generate energy, fusion is much more powerful and also much cleaner as it does not produce radioactive materials as a byproduct.

For these reasons many believe that nuclear fusion is a promising avenue for sustainable and eco-friendly energy in the future.

However, there is still a long way to go until fusion could be viable for commercial use. When asked to comment on the time needed, Kim Budil, the director of the LLNL, stated that “It’s probably two or three decades. Scaling from where we are today to what you would require for a power-generating plant is a pretty significant challenge.”

Director Kim Budil announcing the achievement of fusion ignition in December 2022. Credit: Mary Calvert/REUTERS

Moving forward, the over 8,000 engineers, physicists, and chemists at the LLNL and researchers worldwide will have to find ways to conduct fusion ignition more quickly and cheaply, while also generating much more power. According to Budil, “What we need now is a scientific and investment strategy that allows us to make progress on all of these fronts simultaneously… [because] we need gain of a few hundred to make an energy system.”

Despite the many challenges ahead, Tim Luce, one of the leaders of the international fusion research project ITER, remains hopeful. “A result like this will bring increased interest in the progress of all types of fusion, so it should have a positive impact on fusion research in general,” he states.

~ Rebecca Yang