Aqueous Remediation Of Persistent Organic Pollutants Using Magnetic Nano-Iron Based Sorbent

Hydrophobic Organic Compounds (HOCs) are ubiquitous pollutants that include pesticides and products of industry. Remediation of HOCs is necessary because they persist in the environment, are non-biodegradable, and can be toxic in small doses. Currently, activated carbon is the standard sorbent for removing them from the environment. However, activated carbon binds non-discriminately and requires ex-situ treatment which involves pumping and treating water. Magnetic Permanently Confined Micelle Arrays (MagPCMA) are iron oxide (maghemite) nanoparticles coated with surfactant and silica, which are able to adsorb HOCs and be removed magnetically in a single-step, in-situ treatment.

Research goals were to perform batch experiments comparing the effectiveness of MagPCMA to activated carbon at adsorbing two classes of HOCs, polyaromatic hydrocarbons (PAHs) and halogenated hydrocarbons. The PAHs used were Acenaphthene, Naphthalene, Phenanthrene, and Pyrene; the chlorinated hydrocarbons were Atrazine, Diuron, and Lindane. Experiments were done by dosing sorbents with HOCs in various concentrations and allowing them to equilibrate for 24 hours. Absorbance spectrophotometry, GC-MS, and HPLC were used to determine the amount of HOC sorbed.

MagPCMA was found to be competitive with activated carbon at removing PAHs but not as effective in removing halogenated hydrocarbons. However, it was found that 83.6% of acenaphthene could be recovered from MagPCMA using an acetone extraction and the sorbent could be reused at least five times. The hope for MagPCMA is that it can be used to target specific PAHs and then removed magnetically with minimal ecological impact. Further research will be done on the reusability of the material.