The waste products generated by food oil extraction from peanuts and sunflower seeds may have a beneficial role to play in water treatment. Proteins harvested from the oilseed meal residue created by the extraction process have been demonstrated to effectively adsorb heavy metal contaminants from aqueous systems.

Researchers from Nanyang Technological University, Singapore, and ETH Zurich, Switzerland, isolated proteins from peanut and sunflower oilseed meal and manipulated them to form nanoscale rope-like structures known as protein amyloid fibrils. These structures were then combined with activated carbon to form hybrid filtration membranes.

When applied to the filtration of contaminated water, the membranes were observed to remove up to 99% of the lead, platinum and chromium in solution in compliance with international water drinking standards. The fibrils functioned as molecular sieves, drawing in and trapping heavy metal ions. When saturated with trapped metals, the membranes can be dried out and then burned, enabling recovery and recycling of platinum and other valuable metals.

The filtration membrane described in the Chemical Engineering Journal provides a sustainable use for oilseed waste that would otherwise be discarded or used as food for animal feedstock. Its use could also provide an alternative to high cost and energy-intensive reverse osmosis methods.

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