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Journal of Chemistry
Volume 2015, Article ID 934318, 9 pages
http://dx.doi.org/10.1155/2015/934318
Research Article

Rejection of Organic Micropollutants by Clean and Fouled Nanofiltration Membranes

1Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
2Department of Municipal Engineering, Zhejiang University of Water Resources and Electric Power, Hangzhou 310018, China

Received 5 February 2015; Revised 18 April 2015; Accepted 21 April 2015

Academic Editor: Núria Fontanals

Copyright © 2015 Lifang Zhu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The rejection of organic micropollutants, including three polycyclic aromatic hydrocarbons (PAHs) and three phthalic acid esters (PAEs), by clean and fouled nanofiltration membranes was investigated in the present study. The rejection of organic micropollutants by clean NF90 membranes varied from 87.9 to more than 99.9%, while that of NF270 membranes ranged from 32.1 to 92.3%. Clear time-dependence was observed for the rejection of hydrophobic micropollutants, which was attributed to the adsorption of micropollutants on the membrane. Fouling with humic acid had a negligible influence on the rejection of organic micropollutants by NF90 membranes, while considerable effects were observed with NF270 membranes, which are significantly looser than NF90 membranes. The observed enhancement in the rejection of organic micropollutants by fouled NF270 membranes was attributed to pore blocking, which was a dominating fouling mechanism for loose NF membranes. Changes in the ionic strength (from 10 to 20 mM) reduced micropollutant rejection by both fouled NF membranes, especially for the rejection of dimethyl phthalate and diethyl phthalate by NF270 membranes (from 65.8 to 25.0% for dimethyl phthalate and 75.6 to 33.3% for diethyl phthalate).