Heteroaggregation of titanium dioxide nanoparticles with natural clay colloids.

摘要: To better understand and predict the fate of engineered nanoparticles in water column, we assessed heteroaggregation TiO2 with a smectite clay as analogues for natural colloids. Heteroaggregation was evaluated function salinity (10(-3) 10(-1) M NaCl), pH (5 8), selected nanoparticle concentration (0-4 mg/L). Time-resolved laser diffraction used, coupled to an aggregation model, identify key mechanisms variables that drive Our data show that, at relevant concentration, behavior is mainly driven by colloids, while homoaggregation remains negligible. The affinity electrostatic interactions. Opposite surface charges and/or high ionic strength favored formation primary heteroaggregates via attachment clay. initial shape dispersion state well nanoparticle/clay ratio also affected nature mechanism. With dispersed platelets secondary bridging occurred number greater than 0.5. In NaCl, preaggregated into larger more spherical units. This lower correlated area ratio. this latter case, sticking efficiency could be determined.