Water Science & Technology: Water Supply Vol 1 No 2 pp 99–106 © IWA Publishing 2001
The use of nanofiltration for the removal of pesticides from groundwater:
an evaluation
B Van der Bruggen*, K Everaert**, D Wilms*** and C Vandecasteele****
*
University of Leuven, Department of Chemical Engineering,
Laboratory for Environmental Technology, W. de Croylaan 46,
3001 Heverlee – Belgium Tel. +32 16 32.27.26 Fax +32 16 32.29.91
Email : bart.vanderbruggen@cit.kuleuven.ac.be
**
University of Leuven, Department of Chemical Engineering,
Laboratory for Environmental Technology, W. de Croylaan 46,
3001 Heverlee – Belgium Tel. +32 16 32.27.26 Fax +32 16 32.29.91
***
University of Leuven, Department of Chemical Engineering,
Laboratory for Environmental Technology, W. de Croylaan 46,
3001 Heverlee – Belgium Tel. +32 16 32.27.26 Fax +32 16 32.29.91
****
University of Leuven, Department of Chemical Engineering,
Laboratory for Environmental Technology, W. de Croylaan 46,
3001 Heverlee – Belgium Tel. +32 16 32.27.26 Fax +32 16 32.29.91
ABSTRACT
This study explores the combined removal of four pesticides (atrazine,
simazine, diuron, isoproturon) and hardness from groundwater with
nanofiltration (NF). Four NF membranes were used: NF45 and NF70
(Dow/FilmTec), and UTC-20 and UTC-60 (Toray Ind. Inc.). Each pesticide
was added to groundwater samples in a concentration of 1  g/l,
representative for contaminated sources. For the determination of
pesticides in such low concentrations, an analytical method using
solid-phase extraction and high performance liquid chromatography
was elaborated.
The retentions with NF were compared and explained by means of
molecular size and dipole moment. Molecular size, expressed as an
effective diameter representing the projection of the molecule on
the membrane surface, was calculated by determining the energetically
most favourable molecular configuration. The largest molecules had the
highest retentions, when all other properties are comparable. A high
dipole moment decreases retentions because of charge interactions with
the membrane.
The hardness retentions were high. For drinking water production, it
might be necessary to add hardness after filtration.
The groundwater flux was approximately 5% lower compared to the distilled
water flux. This relatively small flux decline indicates pore blocking due
to adsorption in the membrane pores. The flux decline was proved
reversible; no membrane fouling occurred.
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