3 research outputs found
Polyphosphates and fulvates enhanve environmental stability of PO4-bearing colloidal iron oxyhydroxides
Iron oxyhydroxide nanoparticles (Fe-NPs) are natural vectors of phosphate (PO4) in the environment. Their mobility is determined by colloidal stability, which is affected by surface composition. This might be manipulated in engineered NPs for environmental or agricultural applications. Here, the stability of PO4-Fe-NPs (HFO/goethite) was determined across contrasting environmental conditions (pH, Ca concentration) and by using fulvates (FA) and polyphosphates (poly-P’s) as coatings. The PO4-Fe-NPs are unstable at Ca concentrations above 0.1 mM. Addition of FA and some poly-P’s significantly improved stability. Zeta potential explained colloidal stability across treatments; surface charge was calculated with surface complexation models and explained for phytic acid (PA) and hexametaphosphate (HMP) by a partial (1–4 of the 6 PO4 units) adsorption to the surface, while the remaining PO4 units stayed in solution. This study suggests that Ca concentration mainly affects the mobility of natural or engineered PO4-Fe-NPs and that HMP is a promising agent for increasing colloidal stability.status: publishe
Polyphosphates and Fulvates Enhance Environmental Stability of PO<sub>4</sub>‑Bearing Colloidal Iron Oxyhydroxides
Iron
oxyhydroxide nanoparticles (Fe-NPs) are natural vectors of
phosphate (PO<sub>4</sub>) in the environment. Their mobility is determined
by colloidal stability, which is affected by surface composition.
This might be manipulated in engineered NPs for environmental or agricultural
applications. Here, the stability of PO<sub>4</sub>-Fe-NPs (HFO/goethite)
was determined across contrasting environmental conditions (pH, Ca
concentration) and by using fulvates (FA) and polyphosphates (poly-P’s)
as coatings. The PO<sub>4</sub>-Fe-NPs are unstable at Ca concentrations
above 0.1 mM. Addition of FA and some poly-P’s significantly
improved stability. Zeta potential explained colloidal stability across
treatments; surface charge was calculated with surface complexation
models and explained for phytic acid (PA) and hexametaphosphate (HMP)
by a partial (1–4 of the 6 PO<sub>4</sub> units) adsorption
to the surface, while the remaining PO<sub>4</sub> units stayed in
solution. This study suggests that Ca concentration mainly affects
the mobility of natural or engineered PO<sub>4</sub>-Fe-NPs and that
HMP is a promising agent for increasing colloidal stability