Transport, reactivity, and microbial toxicity of engineered nanomaterials (ENMs) are significantly influenced by the size and surface charge of the nanoparticle aggregates in the environmental media in which they are contained. To remove or separate the colloidal aggregates of ENMs from the aquatic environment, it is important to understand fate and transport of ENMs, and their interaction with other environmental components. Here, we explore the effects of natural organic matter (NOM) and NaCl concentrations on the removal efficiency of hydroxylated fullerene (fullerol) nanoparticle aggregates, nC60(OH)24 by cross-flow ultrafiltration (UF) membranes. We demonstrate that the removal efficiency of nC60(OH)24 (185 nm) by the UF membrane (nominal pore size = 30 nm) was limited at approximately 30%. As NaCl concentration increased from 0 to 1.5 M NaCl, the size of nC 60(OH)24 increased from 185 nm to 1405 nm but the maximum removal efficiency remained below 60%. The presence of NOM increased the stability of nC60(OH)24 and deteriorated the retention of nC60(OH)24 by the UF membranes. The more hydrophilic NOM (i.e., fulvic acid) resulted in lower separation efficiency of nC60(OH)24 by the UF membrane than the less hydrophilic NOM (i.e., humic acid).
Bibliographical noteFunding Information:
This study was supported by Korea Ministry of Environment as “The Eco-Innovation project (Global Top project, Project no. GT-SWS-11-01-002-0), the Ministry of Education (MOE) and National Research Foundation of Korea (NRF) through the Human Resource Training Project for Regional Innovation (No. 2012H1B8A2025906 ), and also supported by the NRF Grant funded by the Korea Government (NRF-2013R1A2A1A09007252). The authors would like to thank Jieun Lee at the University of Sydney for the support for the NPOC analysis.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Filtration and Separation