Monitoring and extraction of uranium in polluted acid mine drainage by super-paramagnetic nanoparticles coated with carbon nanodots

In this contribution, we designed environmentally friendly magnetic nanoparticles for simultaneously monitoring and efficiently extracting uranium (VI) from polluted acid mine drainage (> 99% of the total uranium amount). The nanoparticles consist of super-paramagnetic core made of Fe3O4, which is chemically coated with highly-fluorescent shell made of carbon nanodots. The small nanoparticle diameter enables good water dispersibility, high mobility in suspension and powerful sorbent activity to U(VI) in the presence of sulfates, bicarbonates, and pH 4.3-4.8. The measured detection limit of uranium (VI) in model solutions of acid mine drainage was found to be around 0.8 ppm.