The rare earth

The rare earth elements (REE) is a group of metals including yttrium and fourteen lanthanide elements: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Due to its unique physical and chemical properties, the rare earth elements is vital in a couple of industrial fields, especially in chemical, material and aerospace industry. ^[1]. Therefore, the rare earth elements is called “the Vitamin of Industry”. From the figure besides we can know that the output of rare earth elements varies from country to country.

In fact, compared with other countries China has the greatest potential in rare earth resources. However, there are many inevitable problems in mining, refining and recycling of those rare earth elements. For instance, many rare earth ions are wasted and washed away during process we've just mentioned. ^[2].

The environmental problems

When rare earth elements enters the soil,some of them remain organic,inorganic complexes and ionic state which can be absorbed and recycled directly.

Recovery technology

While research focusing on methods for recycling and recovering rare earth elements have been taken as referecnce, it is not until recently that public attention has been driven to the recycling of rare earth elements. The primary drivers for this renewed focus include the increased demand for rare earth elements, concern about rare earth elements supplies, increasing cost of rare earth elements, and new policies implemented by some countries mandating rare earth elements recycling or selected items.

Figure 3. REE recycling steps and waste emissions.

Rare Earth Enrichment By Optimised Tools

This year we are going to design REEBOT, an engineering e.coli to sense and capture rare earth elements from the industrial sewage intelligently and efficiently. As we know that most of the rare earth elements are lanthanide, so we decide to use LBTS, the most successful lanthanide binders that can selectively bind lanthanide ions with high affinities^[3]. We hope our REEBOT can express the LBTs intelligently after sense the lanthanide ions in sewage. And eventually the REEBOT will be gathered on the silicon surface by si-tag, which is an idea came from our project in 2015. So it limited the bacteria’s expansion to keep safe.

Through our work, we can reduce the pollution of rare earth elements and what's more, recycle those rare earth elements effiently. We believe that REEBOT will be put into real production one day.