Heteroaggregation of PS microplastic with ferrihydrite leads to rapid removal of microplastic particles from the water column

Abstract

Heteroaggregation of microplastic and ferrihydrite leads to sedimentation and therefore removal of microplastic from the water column.

Microbe-mineral interactions in the Plastisphere: Coastal biogeochemistry and consequences for degradation of plastics

“…The distribution of these metals, their sorption onto plastic, and their potential incorporation into minerals associated with plastics is a point of concern for environmental and health risks associated with marine plastic debris. Not only are there health concerns with the plastic associated mineral-microbe biofilm, but this combination of thicker biofilm and increased sorption of metals on plastic in the water column indicates downward transport of the particle due to higher particle mass (Kaiser et al, 2017;Michels et al, 2018;Amaral-Zettler et al, 2021;Schmidtmann et al, 2022).…”

Ferrihydrite coating reduces microplastic induced soil water repellency

“…21 Depending on the pH value, the surface properties of the MP were controlled by the ferric particles. 21 Such iron compounds are not only highly abundant components in aquatic systems but also in soil and soil water (up to 20% (w/w)). 22 MP can get in contact with ferrihydrite (Fh) suspension in unsaturated sand, a situation comparable to and commonly found at the capillary fringe, where anoxic Fe( ii ) bearing groundwater may come in contact with oxygen with subsequent formation of Fe( ii ) to Fh.…”

“…24 However, studies on the interactions between MP and soil components and the resulting changes of MP surface properties are scarce as most studies focus on the interactions of MP and environmental particles in aquatic systems. 21,25,26…”

“…[18][19][20] Recent studies demonstrated the formation of a surface coating and heteroaggregation of PS particles with ferrihydrite (a ferric iron (oxy)hydroxide) in the aqueous phase. 21 Depending on the pH value, the surface properties of the MP were controlled by the ferric particles. 21 Such iron compounds are not only highly abundant components in aquatic systems but also in soil and soil water (up to 20% (w/w)).…”

“…24 However, studies on the interactions between MP and soil components and the resulting changes of MP surface properties are scarce as most studies focus on the interactions of MP and environmental particles in aquatic systems. 21,25,26 Here, we tested if Fh coating inuences the wettability of MP in soil. To this end, we investigated whether hotspots of pristine and coated MP (20-75 mm, PS and PET) embedded in a porous medium consisting of quartz sand will show differences in wettability during capillary rise (Fig.…”