Imagine if we adopted sustainable chemistry to reuse and recycle chemical compounds - especially compounds we create in bulk. I think "Reuse, Recycle" chemistry is the Holy Grail of chemistry, and is much needed to keep in check the accumulations of carbon dioxide, toxic waste from nuclear reactors, and plastics (to name a few). For the chemistry to be sustainable, the end product must also be useful, or at least harmless.
Many scientist are already thinking this way, and this is encouraging. However, there is also a strong movement toward "capturing" the harmful materials and storing them
somewhere - usually inside the Earth. For example, we store nuclear waste in the Earth. There is also a strong movement to capture and store carbon dioxide in the Earth, called Carbon Capture and Storage (CCS) - see
CCP Project.
However, storing things in the Earth is rather risky because these
things can leak out. The CCP Project claims that there needs to be a strong "regulatory framework" with policies for carbon dioxide transfer and storage. However, that's a bit risky too, as such thinking implies potential legal loopholes for maintaining harmful practices.
I urge scientists to combat the "Stuff It and Forget It" strategies with innovative ideas to transform harmful waste products into useful or, at least, harmless substances. Here are some examples of such innovation:
Carbon Dioxide
The evidence is compelling that excess carbon dioxide in our atmosphere is caused primarily by burning carbon-based fuels, such as oil, gas, coal, and biomass. This excess of carbon dioxide contributes to global warming, which holds some unfriendly consequences for life on the planet. Wouldn't it be nice if we could take the excess carbon dioxide and turn it into something else that either we or the planet use?
One way to handle carbon dioxide is to "hire" more trees. Trees are natural "sustainable chemists" that absorb carbon dioxide and, using Sun's energy, turn it into oxygen and other harmless stuff. However, we can't grow enough trees quickly to help us with global warming. Believe it or not, most deforestation occurs because of poverty, where people in developing and undeveloped nations cut down trees for fuel. Until we can secure more tree, is there anything else that can be done?
From the chemists' perspective, carbon dioxide is not likely to react with most substances, and typically requires a lot of energy for chemical reaction to occur. That's why the carbon dioxide we emitted for the past 100 years of burning carbon fuels continues to sit and accumulate in our atmosphere, contributing to global warming.
However, one group at Michigan Tech found a way to combine carbon dioxide with Li3N to produce a semiconductor, a material that's used to make fertilizers, and energy! (See
From Lemons to Lemonade: Reaction Uses Carbon Dioxide to Make Carbon-Based Semiconductor.) Pretty exciting!
The questions I have for the Michigan Tech team and others are:
- How much Li3N do we need, and how readily available is it? Will this process be viable for industrial scale carbon dioxide transformation?
- How much semiconductor and pre-fertilizer material do we really need? Is there such a thing as too much of these substances?
- What happens to the semiconductor and pre-fertilizer materials after use - do they degrade into useful or, at least, harmless materials?
Gasoline vs. Hydrogen Cars
Gasoline is a carbon-based fuel derived from oil that contributes to carbon dioxide emissions. However, hydrogen is an energy carrier that can be an alternative to gasoline. Hydrogen can react with oxygen and produce water from the tailpipe.
The current drawbacks of hydrogen fuel are "low energy content per unit volume, high tankage weights, very high
storage vessel pressures, the storage, transportation and filling of
gaseous or liquid hydrogen
in vehicles, the large investment in infrastructure that would be
required to fuel vehicles, and the inefficiency of production processes." (
Wikipedia) Deal breakers? No. Just challenges to overcome in the name of sustainability.
Microbes Hired for Wastewater Cleaning
At Oregon State University, engineers have developed an
innovative process that produces electricity directly from wastewater with the help of microbes. Bacteria oxidize the organic matter to produce
electrons within a fuel cell. This process could work for any type of organic waste
material can be used to produce electricity, such as grass straw, animal waste, and byproducts from such operations as
the wine, beer or dairy industries. In addition, this process could provide necessary electricity in developing countries, where treatment plants for sewage are nonexistent.
Again, the current challenge is to make this process efficient and cost effective on a large scale. Way to go Oregon State University team!
Nuclear Waste Transformation
The Environmental Energy Resources (EER) company, based in Israel, has found a way to
transform low-radioactive, medical, and industrial waste to produce water, glass, and clean energy.
EER's waste disposal reactor does not harm the environment
and leaves no surface water, groundwater, or soil pollution in its wake.
The EER reactor combines three processes into one solution: it uses
plasma torches to break down the waste; carbon leftovers are then
gasified and finally inorganic components are converted to solid waste.
The remaining vitrified material is inert and can be cast into molds to
produce tiles, blocks or plates for the construction industry.
Thus, instead or burning the waste, which produces harmful by-products, the waste is transformed in biofriendly ways.
EER describes their patented PGM technology as "
plasma-sizing" huge piles of waste into a pile of black rocks.
According to their website, EER has been working on numerous of projects around the world to provide
a solution to dispose of waste while harnessing energy. For example,
EER will provide the PGM technology to a Waste to Energy (WtE) project
in the US for the removal of municipal waste. In the UK and Eastern
Europe, EER is working with local developers to establish a PGM Waste to
Energy processing plant.
Summary
I am very excited about the innovations occurring around the world to help us reduce our carbon (dioxide) and other footprints. I urge our scientific community to think out-of-the-box and holistically about our planet's chemistry to uncover the Holy Grail of
Waste In (+ Energy) = Useful or Harmless Compounds (+ Energy)
When energy IS required to treat waste, can we use clean and renewable input as energy, such as solar or wind? Many scientists still wince at the thought of using more energy to treat waste products. However, the energy we use does not need to leave a carbon footprint!