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 (Fe2O 3), titanium dioxide (TiO2), and silicon dioxide (SiO 2). 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 1.0mg/L for Fe2O3 and TiO2, and 5.0 and 10mg/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 nanoparticle concentrations, and with varying amounts of PAC. Isotherm data showed a higher degree of adsorption in the presence of Fe2O 3 and TiO2 nanoparticles, regardless of concentration. In activated carbon-free experiments both Fe2O3 and TiO 2 nanoparticles alone were observed to act as adsorption sites for TCE by removing up to 60% of TCE from the aqueous phase. Silica appeared to have no impact on TCE adsorption at either of the concentrations evaluated, except in the presence of humic acid. This study provides important information related to the use of nanoparticles in water treatment and their impact on the performance of a commonly used adsorbent used to remove organic pollutants. No studies to date have attempted to quantitatively describe the adsorption behavior of TCE to PAC in the presence of TiO2, SiO2, and Fe2O3 nanoparticles.
- Activated carbon
- Particle size distribution (PSD)
- Trichloroethylene (TCE)
ASJC Scopus subject areas
- Environmental Chemistry
- Waste Management and Disposal