Science Inventory

Effects of source and seasonal variations of natural organic matters on the fate and transport of CeO2 nanoparticles in the environment

Citation:

Li, Z., E. Sahle-Demessie, A. Aly Hassan, J. Pressman, G. Sorial, AND C. Han. Effects of source and seasonal variations of natural organic matters on the fate and transport of CeO2 nanoparticles in the environment. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 609:1616-1626, (2017). https://doi.org/10.1016/j.scitotenv.2017.07.154

Impact/Purpose:

A better understanding of the fate and transport of engineered nanoparticles (ENP) in the presence of natural organic matter (NOM) is important determine their potential health and environmental risk. The stability and transport of ENP through saturated porous media are studied to simulate conditions of drinking water treatment. In this study we used NOM from the Ohio River which is relevant to evaluate the efficacy of drinking water filtration on removing ENP from drinking water sources. The study is intended to informpublic water utility operators and drinking water system designers on methods of optimizing the effectiveness of filtration processes on nanoscale ENP contaminants.

Description:

Natural organic matter (NOM) affects the stability and transport of nanoparticles (NPs) in natural waters by modifying their physiochemical properties. Source location, and seasonal variations, influence their molecular, physical and electrical charge properties. To understand the variations of NOM on the mobilization of NPs, large volumes of water were collected from the Ohio River (OR) over winter and summer seasons and dissolved NOMs were concentrated. The chemical and structural differences of these NOMs were compared with Suwannee River humic acid (SRHA) using 1H and 13C nuclear magnetic resonance spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. Thermal analysis and FTIR confirmed that differences in composition, structure, and functional groups are a result of SRHA fractionation compared to whole molecule OR-NOM. The influence of OR-NOMs on the surface charge of CeO2 NPs and the effects on the transport and retention in a three-phase (deposition-rinse-re-entrainment) sand-packed columns were investigated at an initial concertation of 10 ppm, pH 6.8, increasing ionic strength (3, 5, and 10 mM), retention time of 1 min, and increasing NOM concentration (1, 5, and 10 ppm). The summer OR-NOM showed higher stabilization and mobilization effect on the CeO2 than the winter NOM; while their effect was very different form the SRHA. The stabilization of NPs is attributed to both electrostatic and steric effects. The differences in the chemical structure of the complex and heterogeneous NOMs showed disparate reactivity and direct impact on CeO2-NPs stability. Using SRHA to study the effect of NOM for drinking water related assessment does not sufficiently represent the natural conditions of the environment.