Removal of arsenic from water by iron oxide nanoparticles impregnated on carbon nanotubes.

The removal of Arsenic (As (III)) ions from water using modified multi-walled carbon nanotubes (MCNTs) was demonstrated in this study. Results of the study showed that raw (non-modified) MCNTs have very poor efficiency in removing As (III) from water by conventional adsorption mechanisms. However, when MCNTs were modified with iron oxide (Fe-MCNTs), a significant improvement in the As (III) removal efficiency was observed. Results of the study also showed that Fe-MCNTs have much higher efficiency in removing As (III) than MCNTs modified with carboxyl group (COOH-MCNTs). Under the experimental conditions used in the study, about 77.5% of As (III) removal was achieved by the Fe-MCNTs, while COOH-MCNTs removed only 11% at pH 5. In addition, the adsorption kinetics of MCNTs indicated that there is a strong affinity of As (III) ions to the surface of the Fe-MCNTs.