Adsorption of Pb, Cd, Cu, Zn, and Ni to titanium dioxide nanoparticles: effect of particle size, solid concentration, and exhaustion
2011
Engates, Karen E | Shipley, Heather J
Purpose Adsorption of metals (Pb, Cd, Cu, Ni, Zn) to TiO₂ nanoparticles and bulk particles was examined for use as a contaminant removal substrate as a function of particle size, sorbent concentration, and exhaustion. Methods Adsorption experiments were conducted with 0.01, 0.1, and 0.5 g/L nanoparticles in a pH 8 solution and in spiked San Antonio tap water. Results When results were normalized by mass, nanoparticles adsorbed more than the bulk particles but when results were surface-area normalized, the opposite was observed. The adsorption data shows the ability of the TiO₂ nanoparticles to remove Pb, Cd, and Ni from solution with similar adsorption at 0.1 and 0.5 g/L. Adsorption kinetics for all metals tested was described by a modified first order rate equation with the nanoparticles having a faster rate of adsorption than the bulk particles. The nanoparticles were able to simultaneously removal multiple metals (Zn, Cd, Pb, Ni, Cu) from both pH 8 solution and spiked San Antonio tap water. Exhaustion experiments showed that both the nanoparticles and bulk particles were exhausted at pH 6 but at pH 8, exhaustion did not occur for the nanoparticles. Conclusion Comparison of K d, distribution coefficient, with other literature showed that the nanoparticles were better sorbents than other metal oxide nanoparticles and a commercial activated carbon.
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