Mercury pollution threatens the environment and human health across the globe. Mercury is a highly toxic substance that has found uses in many places throughout industry, including coal mining, small-scale gold mining, some agricultural activities, and various metallurgic processes.

Justin M. Chalker, Flinders University, Bedford Park, Australia, and colleagues have developed a porous polymer as a low-cost sorbent for mercury. The team combined elemental sulfur and common cooking oils, including olive oil, canola oil, and sunflower oil. In the first step, sulfur was heated to 180 °C to initiate a ring-opening polymerization. Then, an equal mass of oil was added and stirred vigorously to ensure homogenous mixing. The process produces a polymer that ensures enough sulfur availability for mercury capture, while not being too brittle. The synthesis could be easily scaled to give 40 g of polymer. According to the researchers, larger, industrial-size batches should also be possible.

The mercury-capture properties of the sulfur/canola oil polymer were tested. In solution (2 g of polymer to 5 mL aqueous solution of HgCl₂), on average, 90 % of the mercury was removed after 24 hours. In a test of pure liquid mercury, 1 g of the polymer could remove 99 % (99 of 100 mg) mercury, producing metacinnabar, a non-toxic, non-water-soluble form of mercury. Another common pollution problem is mercury waste within soil. For this, the polymer was shown to effectively remove mercury traces within 24 hours from mercury-treated soil samples. The polymer particles could be separated afterward by simple filtration.

Further studies were undertaken after preparing a more porous version of the polymer by synthesis in the presence of a sodium chloride porogen. This material was able to remove up to 67 % mercury from Hg-containing nitrogen flows. It was also effective (up to 81 %) in removing mercury bound to organic matter, as well as from aqueous solutions of organomercury fungicides. This shows promise for applications as a soil additive to prevent mercury leaching from agriculture into wastewater. Neither the polymer itself nor the mercury-bound polymer are toxic to human cells.

• Laying Waste to Mercury: Inexpensive Sorbents Made from Sulfur and Recycled Cooking Oils,
  Max J. H. Worthington, Renata L. Kucera, Inês S. Albuquerque, Christopher T. Gibson, Alexander Sibley, Ashley D. Slattery, Jonathan A. Campbell, Salah F. K. Alboaiji, Katherine A. Muller, Jason Young, Nick Adamson, Jason R. Gascooke, Deshetti Jampaiah, Ylias M. Sabri, Suresh K. Bhargava, Samuel J. Ippolito, David A. Lewis, Jamie S. Quinton, Amanda V. Ellis, Alexander Johs, Gonçalo J. L. Bernardes, Justin M. Chalker,
  Chem. Eur. J. 2017.
  DOI: 10.1002/chem.201702871