What are the questions?
You must be wondering from the title. How is Nanotech truly going to change Climate Change? What are the applications? Is it even possible?
The Devastating Problem
Climate Change as you know has been affecting people and habitats globally. 3.3 billion people are highly vulnerable by this climate crisis. Policies in place by the end of 2023 would likely see temperatures exceed 1.5C this century and reach around 3.2C by 2100. There are already huge ice glaciers melting in the North and South Pole as well as Antartica. This could result in floods and waves and essentially wipe out the whole human existence! Scientists have had a huge debate on whether it is too late or not, but everyone is trying everything that they can in order to fight climate change.
Imagine a man in Chad, one of the most vulnerable countries in the world towards Climate Change, having with the sweltering heat just beating constantly on this individual. There is constant rise for hunger and people are fighting for food as Climate Change kills the crops that farmers are making and droughts are ocurring. The individual will have to walk miles to find water in order to sustain him and his family; otherwise, it will be too late. He could see people dropping like flies because of having no access to water and food, despite having enough money that could help them to survive.
Climate Change is inevitable as many gas emissions are used today in society to fuel everything we need. In many parts of the world, humans and ecosystems will be unable to adapt to this amount of warming, and the losses and damages will “escalate with every increment” of global temperature rise. This is why it is so important to at least reduce if not mitigating climate change today.
So, What’s the Revolutionary Solution?
I am glad you asked. The solution is something so small you cannot even see it. Something so minusicle you would not even notice it. This “thing” is in normal technology today, and it is probably in the device that you are reading from. That’s right, nanotechnology.
What is Nanotechnology?
Nanotechnology is what it sounds like, technology at the nanoscale. Want a reference of how small a nanometer is? Imagine 100,000 nanometers on 1 hair strand. In 2012, our smallest chip could reach 10,000 nanometers, but today, we can now reach to 1 nanometer for a single chip. Imagine 100,000 chips on a single strand of hair.
This size and ability to store data and work with technology allows nanotechnology to be one of the most revolutionary industries in the world.
Nanotechnology will basically affect every industry from filming to cybersecurity to medical fields. However, there are different types of nanotechnology designated for each one like subsections. The one used for Climate Change is nanoparticles.
The Little Absorbers
Nanoparticles contain larger surface area per unit volume, which adds an advantage with transporting clean energy and adsorbing greenhouse gases. This higher surface area allows for more CO2 emissions to be absorbed as emissions have more interactions with these nanoparticles.
Nanoparticles have special properties that allows them to regenerate. This regenerative property allows to them to last longer into absorbing the emissions that are so prevalent in engines and in the general environment.
The Verifying Experiment
Nanoparticles of Fe3O4, Fe3O4–proline, Fe3O4–lysine, and Fe3O4@SiO2–NH2 were placed in water. The effects of initial pressure of CO2, nanoparticles and nanoparticle concentration on absorption performance were examined. The obtained results indicated that the presence of Fe3O4 nanoparticles resulted in better results at pressure 30 bar in water as a physical absorbent, and they enhanced the absorption up to 17.61% and 34.23% compared to non-functional Fe3O4 water, respectively.
Furthermore, the dispersed nanoparticles in the MDEA nanofluid shows that the functional Fe3O4 nanoparticles were effective for CO2 separation even in chemical absorbents, and under the best conditions, they enhanced the capacity of absorption up to 16.36% at pressure 40 bar.
Moreover, zeta potential analysis, the graphs used into seeing if the nanoparticles provide stability in the base fluids, revealed that Fe3O4–lysine and Fe3O4@SiO2–NH2 nanoparticles are more stable than non-functional Fe3O4 and Fe3O4–proline in the base fluid.
In this picture, this resembles the summary of the experiment that was carried out by these magnetic nanoparticles.
Bubble breaking as shown by the picture occurs when intially, it start with the separation of CO2 and nanoparticles, but eventually, the nanoparticles start to become unstable, thus testing the stability of nanoparticles at base fluids using the zeta potential analysis in order to cause the reaction for the carbon emissions to break.
Another method as shown by the picture is the Brownian Method. The Brownian method is essentially a sporadic movement of particles suspended in a solution due to the interaction between the particles and fast-moving atoms in gas or liquid. As shown in the diagram, the carbon is clustered in the middle or in the medium where it is trapped in the middle and preventing the carbon emissions from escaping.
The last method shown in the picture is the Grazing Effect. The Grazing Effect is where nanoparticles diffuse across to the carbon, and it is absorbed directly to on the surfaces of the nanoparticles. This allows for the carbon to be trapped within the nanoparticles as it moves across the gradients.
These methods were tested during the experiment as well when figuring out the ways these magnetic nanoparticles of Fe3O4, Fe3O4–proline, Fe3O4–lysine, and Fe3O4@SiO2–NH2 could prove these methods of absorbing carbon emissions.
Nanoparticles Teaming with the Ocean
The ocean is so vast, reaching up to 139 million square miles, and one of its main functions is reducing the amount of climate change in the environment. Not only does the ocean cool down Earth and remove the heat from the environment, but they also reduce the carbon emissions present using these small living organisms called phytoplankton. Phytoplankton converts carbon emissions through photosynthesis into living tissue, an amazing way to turn something deadly into something reviving. The phytoplankton then sinks to the sea floor, taking the absorbed carbon into the depths of the ocean for centuries to come.
But how does nanoparticles come into play? Glad you ask. So, phytoplankton requires a fertiliser or combination of iron and other nutrients to be given in order to flourish, and scientists have faced the problem of providing these nutrients. One way scientists have tried was directly pumping these nutrients into the ocean, but this proved to be inefficent or if it did help the phytoplanktons to flourish, it would not absorb as much carbon dioxide as natural blooms occured.
A new scientific paper authored by Dr. Peyman Babakhani from the University of Leeds debates that these problems can be solved if engineered nanoparticles to deliver fertiliser to the phytoplankton and would be cost-beneficial as they have the ability to regenerate and would not waste an excess amount of resources.
Directly quoted by the paper, “Our study [, based on 123 studies previously,] shows that the use of several types of engineered nanoparticles in ocean fertilisation can be promising in terms of costs and carbon dioxide emissions during production and delivery processes, and such nanoparticles can be applied at concentrations lower than those that might cause toxicity to marine ecosystems.”
As you have read from the last sentence of the quote, there is a public fear of the nanoparticles being toxic to the marine environment as they are engineered particles being placed into a natural ecosystem and requires assessments before putting them into the ocean. However, scientists believe that turning nanoparticles into become non-toxic is possible to achieve.
The ocean has been a big asset into fighting climate change from the very beginning, and sceintists has been researching for years how we could further enhance our ways into making the ocean a powerhouse absorber. They wanted to find another way to make phytoplanktons, the main reason why the ocean absorbs 25% of carbon emissions on Earth, but this could even turn to double if not triple of carbon emissions being absorbed once we have harnessed this new technology that is being implement by marine specialists and nanotechnology scientists.
The Bubble Breakup
Among many of the methods of reducing carbon emissions such as absorption or membrane separation, the most popular and revolutionizing is using organic liquids to absorb CO2 from gas as it proves a huge decarbonization and a simple process to be implemented.
In particular, the addition of the nanoparticles in the gas-liquid flow is a viable way in removing carbon emissions by improving the mass transfer across the gas-liquid interface. The high CO2 absorption rate can be obtained under room temperature by adding Al2O3 nanoparticles into the methanol absorbent specifically.
Bubble columns provide a large interfacial area that would be used for the nanoparticles in order for them to interact with the carbon dioxide. The gas is consists of bubbles via the holes at the bottom of the column that then travels through the liquid. Bubble coalesence and breakup are interaction that affect the performance of contactors (systems that bring different phases, generally gas and liquid, for mass transfer or reactions). This determines the bubble size and eventually the bubble rise velocity by the change of the interfacial area and gas holdup, leading into. influencing the interphase mass transfer rate. Challenges include consistently keeping efficient flow conditions, requiring an understanding of bubble interaction dynamics and the mass transfer interactions
The first basic experiment involving bubble coalescence was conducted by Calderbank et al. It was agreed that coalescence occurs when the following bubbles gather behind the leading bubble, where the bubble wake plays a vital role in both capturing non-aligned bubbles and the possible subsequent coalescence
In recent decades, computational investigations have been implemented to experiment the changes in geometric structure over locations and time and through the interactions among and between discrete phases and fluid flow. In particular, the population balance model (PBM) can predict the local size distribution of fluid entities by accounting for the coalescence and breakup. The application of the PBM is significant to predict the bubble population dynamics gas-liquid systems
Now, how does this correlate with nanotechnology?
An experiment was conducted in Korea University by Yong Tae Kang and Lirong Li consisting of, the bubble coalescences and breakup interactions in a rectangular bubble column for CO2 absorption in methanol with various concentrations of Al2O3 nanoparticles, creating the gas-liquid system. A high-speed camera and simultaneously visualized via simulations with the PBM to determine bubble size distributions. Then, a series of parameters correlated with the bubble interaction behaviors, such as the bubble velocities, bubble wake patterns, path instability, and frequencies of bubble coalescence and breakup, were examined. The mass transfer coefficient and the bubble behaviors is also considered for the carbon dioxide to be transferred to these bubble interaction in order to be absorbed by these nanoparticles.
In conclusion, the nanoparticles proved to be incredibly effecient for the carbon dioxide absorption based on the gas-liquid nanoparticle model system that was utilized during the experiment, and this was extremely important experiment as it proved the way fluid dynamics could be essential with the use of nanoparticles in order to eradicate carbon dioxide.
Final Conclusive Thoughts
As we have seen on how nanoparticles are essential to the defeat of climate change, it is in the power of scientists and engineers to capitalize on this opportunity of nanotechnology to absorb carbon dioxide and further enhancing the way we already decarbonize the environment. Now do you believe me how something so small can have a tremendous impact?