Magnetic pollen grains as sorbents for facile removal of organic pollutants in aqueous media

► Novel use of a natural material (pollen) to absorb hydrophobic organic contaminants from contaminated water. ► High sorption comparable to activated carbon. ► Pollen can be used “as is” or magnetized by depositing magnetite on the surface, to improve removal of the magnetized pollen from solution. ► Wide range of contaminants studied. ► Raw or magnetized pollen can be regenerated after use for multiple cycles of adsorption. Plant materials have long been demonstrated to sorb organic compounds. However, there are no known reports about pollen grains acting as sorbents to remove hydrophobic organic compounds (HOCs) such as pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from contaminated waters. We report a facile and effective method to remove HOCs from water using magnetized short ragweed ( Ambrosia artemisiifolia) pollen grains. We dispersed the magnetized pollen grains in two different water samples – deionized (DI) and natural storm water to mimic real environmental conditions likely to be encountered during treatment. The magnetized pollen grains were readily separated from the aqueous media via a magnetic field after adsorption of the HOCs. We measured the adsorption of five representative HOCs (acenaphthene, phenanthrene, atrazine, diuron, and lindane) onto magnetized ragweed pollen in different aqueous matrices. We demonstrate that the adsorption capacity of the magnetized ragweed pollen can be regenerated to a large extent for reuse as a sorbent. Our results also indicate that the magnetized pollen grains are as effective as activated carbon (AC) in removing HOCs from both types of contaminated waters. The high HOC sorption of the ragweed pollen allows it to have potential remediation application in the field under realistic conditions.