Authors: X. Zhang, Y. Chen, H. Sun and J.C. Crittenden
Affilation: Arizona State University, United States
Pages: 616 - 619
Keywords: adsorption, desorption, Cadmium, nanoparticles, and bioaccumulation
There are increasing concerns about the health and environmental impact of nanomaterials. The study of Sun et. al 2006 provided the evidence of facilitated bioaccumulation of As(V) in carp in the presence of titanium dioxide nanoparticles. Adsorption and desorption of toxic pollutants by nanoparticles may dramatically affect the facilitated transport ability of nanoparticles. In this study the adsorption/desorption abilities of Cd onto TiO2 nanoparticles and natural sediment particles (SP) were studied and their different facilitated transport ability were assessed. The results showed that TiO2 nanoparticles had a significantly stronger adsorption capacity for Cd than SP. The isotherm data followed Freundlich isotherm and the constants KF and n were found to be 32.8 mg/g and 0.956 for P25 and 3.25 mg/g and 1.03 for SP. The small particle size, large specific surface area and the more negative zeta potential of P25 may account for their strong adsorption ability. After 144 h’s desorption, Cd desorption percentage from P25 is about 6% lower than that form SP, however, the desorbed amount of Cd from P25 are much more than those from SP (Table 1). Facilitated transport abilities of toxic pollutants by particles are related to the adsorption/desorption capability of the particles. The large adsorption and desorption amount of P25 indicating that they may have a significantly influence on the mobility and bioavailability of Cd in aquatic environments. The results of bioaccumulation tests showed that the presence of SP did not have significant influence on the accumulation of Cd in carp during the 25 d of exposure. However, the presence of TiO2 nanoparticles greatly enhanced the accumulation of Cd in carp. After 25 d of exposure Cd concentration in carp increased by 146%, and the value was 22.3 and 9.07 ?g/g, respectively.