Impact of Nanoparticles and Natural Organic Matter on the Removal of Organic Pollutants by Activated Carbon Adsorption

Isotherm experiments evaluating trichloroethylene (TCE) adsorption onto powdered-activated carbon (PAC) were conducted in the presence and absence of three commercially available nanomaterials: iron oxide (Fe2O3), titanium dioxide (TiO2), and silicon dioxide (SiO2). Isotherm experiments were also conducted in the presence and absence of natural organic matter (NOM), in the form of humic acid, to more closely model natural water conditions. Nanoparticles at two concentration levels (0.5 and 1.0 mg/L for Fe2O3 and TiO2, and 5.0 and 10 mg/L for SiO2) were considered. Zeta potential and pH of point of zero charge (pHpzc) of the nanoparticles and the PAC were measured. Particle size distribution (PSD) of the nanoparticle dispersions was analyzed as a function of time to determine the nanoparticle size range of each dispersion. Aggregation of Fe2O3 and TiO2 nanoparticles was observed but not for SiO2 nanoparticles. Adsorption isotherm experiments were conducted at three initial TCE concentrations, two ...