Institute for Sustainability

Using magnetic biochar to absorb and recover CECS

Towards understanding the fate of contaminants of emerging concerns (CEC): Using magnetic biochar to absorb and recover CECS from soil

Summary

Contaminants of emerging concerns (CECs) such as nonylphenol, oxybenzone, bisphenol A, benzophenone, and benzotriazole originate from the use of consumer products like detergents and sunscreens and are increasingly found in the soil environmental and may enter the food chain via plant uptake. CECs interact differently with components of the soil. On some soil matrix components, they bind strongly and thus become sequestrated while on others they bind weakly - if at all - and are readily released back into the environment making them available to plants. A research team at Politecnico di Milano, Italy, has done extensive work on the cultivation of crops on CEC contaminated soils. Their findings have shown the possibility of plant uptake of CECs which can serve as a plausible pathway by which humans are exposed to these potentially harmful compounds. In order to properly interpret the CEC plant uptake data, further understanding of the soil CEC sorption is essential. This overseas research visit sponsored by the Institute for Sustainability Enviresearch Foundation Travel Award will evaluate the sorption properties of CECs on agricultural soils in order to further understand and predict the fate of CECs in the soil environment.

Biochars (i.e. charcoal) have superior sorption properties than soil minerals or soil organic matter, so the addition of biochars will help in reducing CEC bioavailability in contaminated soils by reversing the partitioning of already existing CECs within the soil in favour of association with biochar. By their high sorption capacities, biochars may enable a long-term sequestration of existing CECs and provide continuous protection against future CEC exposures. This will make it possible to maintain low bioavailable levels of these contaminants even with the use of reclaimed wastewater and biosolids for agricultural purposes. The study will also investigate the use of magnetic biochar as a means of remediating severely CEC contaminated soil by focusing on; (i) the sorption of already existing CEC in the case of historic exposures, (ii) the evaluation of their useful service life in providing ongoing protection against present and future CEC exposures and (iii) the possibility of restoring contaminated soils to their original state by the removal of CECs associated with magnetic biochars using magnetic separation.

Enviresearch magnetic biochars