Removal of Selenium from Aqueous Solutions Using Magnetite Nanoparticles as Adsorbent

Selenium (Se) is a problematic contaminant for many regions worldwide. Adsorption is by far the most researched and most promising method in treating Se laden waters. The major limitations in using those adsorbents are the preferential adsorption for either selenite (SeO3) or selenate (SeO4) and interferences by anions such as phosphates. The objective of this study was to remove Se from aqueous solutions using the synthesized magnetite nanoparticles as an adsorbent. In this study, a series of batch adsorption experiments were performed to study the effects of pH, temperature, concentration, contact time, and presence of competing anions on Se removal efficiency. Compared with either natural magnetite (<5μm) or nano-iron (~10 nm), magnetite nanoparticles(10-20 nm) were more effective as an adsorbent for selenite, while nano-iron was found to perform better to remove selenate.