Batch Studies of Heavy Metal Sorption Using Nano-Metal Oxides

Abstract

Safe drinking water is paramount to human survival. Current treatments do not adequately remove all heavy metals from solution, are expensive, and use many resources. Metal oxide nanoparticles may be ideal sorbents for heavy metals due to their smaller size and increased surface area in comparison to bulk media. Heavy metal adsorption (Pb, Zn, Cd) to hematite (Fe 2 O 3 ) and aluminum oxide (Al 2 O 3 ) nanoparticles was examined as a function of pH for use as a contaminant removal substrate in water treatment technology. Batch sorption experiments were conducted with 0.1 and 0.5 g/L nanoparticles. Adsorption results showed metal pHdependency with a Freundlich isotherm fit. Two-step desorption experiments using Pb and Cd indicated that Pb and Cd appeared to be irreversibly sorbed to the surface of hematite nanoparticles in the same solution conditions. Other experiments were conducted to determine the removal efficiency of multiple metals in solution by the nanoparticles. 0.5 g/L hematite nanoparticles simultaneously removed greater than 70% of Pb, Zn, Ni and Cd.