Tag Archives: Heavy metals

Is the World Set to Run Out of Cobalt?

Cobalt is an important part of most batteries, and our global supply is running low. The demand of cobalt in the next 10 years is expected to increase by roughly 300%, and a team of researchers from the Massachusetts Institute of Technology decided to investigate exactly how much of a problem this increased demand could be.

Lithium-ion batteries, such as the ones found in electric cars and most smart phones, require a cathode for the battery to operate, and cobalt is the most common choice due to having a high energy density compared to its competitors. The study focuses on the amount of cobalt we are mining and processing now compared to how much we will need by 2030. By their estimates, the world may require 450 k tonnes per year in cobalt.

Values interpolated from research data. Source: Fu et al.

The researchers employed a methodology of analyzing market trends in the sales of electric cars, which account for roughly 60% of all cobalt use. To determine the amounts of cobalt production, they surveyed mining companies to determine the amount of cobalt being produced in cobalt mines, and as a by-product in non-cobalt mines. With these values as their main metrics, they made projections for the next decade with the hopes of seeing if, and when, our cobalt might run short.

 

The methodology is not perfect, however; it is a forecast and not a guaranteed trend. Thus, the data presented is largely extrapolated and estimated from general trends. But the goal of the paper was not to draw exact conclusion. Their goal was to investigate how sustainable this resource is in the short term.

 

The main take-away from their paper are that end-of-life reclamation of cobalt-reliant materials is going to start being more and more necessary. So even with all of our new technologies, the message of sustainability stays the same: Reduce, Reuse, Recycle!

Griffin Bare

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Revised: New Method of Water Purification can Clean Out Mercury and Other Harmful Metals

Carbon nanostructures have the potential to be used as a new form of water purification. A team of researches out of the Indian Institute of Technology Bombay have shown the potential to clean out Mercury, Cadmium, and Chromium ions safely from drinking water.

 

The study, which came out at the end of December 2019, shows that three-dimensional nanostructured carbon florets (NCFs) are tightly packed enough to inhibit heavy metal ions such as Hg2+ and Cd2+ form passing through, while allowing the much smaller H2O molecules to pass through easily. This material is particularly good at adsorbing out multiple heavy metal ions simultaneously, making it uniquely qualified for practical use in water filtration systems.

Effectiveness of NCFs

Source: Moronshing et al. (adapted)

As you can see in the above image, the NCFs plug the narrow pathway for the contaminated water to reach the receiving flask. As the water molecules pass through, the pollutants are almost entirely blocked. The chart bellow specifies that as much as 93% of the heavy metals ion are removed from the solution, simply by passing through this NCF filter.

NCF Adsorption Efficiency

Source: Moronshing et al. (adapted)

Ease of Implementation

The most interesting aspect of this discovery is how easy it is to use. No energy is required to enable these filters, the water source simply passes through, and between 80% to 90% of the ions are instantly trapped.  The study further shows that NCFs are easy to reclaim after use and have long lifespans. These structures act very simply as a filter for harmful meta ions; a microscopic filter for atoms.

Synthesis of NCFs

Source: Moronshing et al. (adapted)

Furthermore, these NCFS work on a range of pH 2-13, with no significant drop across this large range. This means it can perform well on most all samples of water, and effectively decontaminate water safely. NCFs are also synthesized in a very simple fashion, requiring only minor modifications to an already common nanomaterial known as DFNS (dendritic fibrous nanosilica).

While there is certainly room for expansion into purification of other heavy metals that pollute water supplies, such as lead, this is a very promising step forwards!

-Griffin Bare