University thesis:
Dissertation, Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2021
Footnote:
Description:
The focus of this work is on the use of superparamagnetic iron oxide nanoparticles (SPION) for the remediation of hydrocarbon-based contaminants from water. SPION are chosen as the core material for the sorbent due to their unique properties. As nanoparticles, they possess a huge surface area which is the interactive area and thus, determines the sorbents' efficiency. Further, the superparamagnetic behaviour – strong magnetic response under a magnetic field applied without magnetic remanence – allows good dispersion of the particles but easy collection once a magnetic field is applied. As SPION naturally do not show a significant tendency to adsorb organic contaminants, they are functionalized with a self-assembled monolayer based on various phosphonic acid (PA) molecules. These PA render the SPION hydrophobic and oleophilic. First, the described SPION-SAM systems are functionalized and characterized. The surface functionalization is successful, regardless of the employed type of metal oxide as core and the PA molecules as the shell. However, the degree of surface functionalization is largely dependent on the employed molecules. In contrast, the core has no significant influence on the degree of functionalization. On the other hand, it influences system properties such as the surface charge and thus, the dispersibility. In a second step, the described sorbents are used to extract crude oils and model contaminants from water. The sorbent shows good extraction rates of up to 4.8 g/g sorbent. The comparison of various extraction substances showed that the extraction is more efficient for more viscous contaminants. Variations in the remediation efficiency are also assigned to different segregation tendencies of oil to water and binding strength among oil molecules. The type of surface functionalization plays a subdominant role in the removal of liquid contaminants, as long as the oleophilic nature is granted. On the other hand, the PA functionalization grants degradation-free reusability. Third, nanoplastics debris ...