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Changes in surface properties and separation efficiency of a nanofiltration membrane after repeated fouling and chemical cleaning cycles

Journal Article


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Abstract


  • The aim of this study was to evaluate the changes in membrane surface properties and solute separation

    by a nanofiltration membrane during repetitive membrane fouling and chemical cleaning. Secondary

    treated effluent and model fouling solutions containing humic acids, sodium alginate, or silica colloids

    were used to simulate membrane fouling. Chemical cleaning was carried out using a commercially available

    caustic cleaning formulation. Carbamazepine and sulfamethoxazole were selected to examine the

    filtration behaviour of neutral and negatively charged organic compounds, respectively. Results show

    that the impact of membrane fouling on solute rejection is governed by pore blocking, modification of

    the membrane surface charge, and cake enhanced concentration polarisation. Caustic cleaning was effective

    at controlling membrane fouling and membrane permeability recovery was slightly more than 100%.

    In good agreement with the literature, the high membrane permeability recovery observed here suggests

    that caustic cleaning could lead to temporary enlargement of the membrane pores. In addition, microscopic

    observations based on scanning electron microscopy and energy dispersive spectroscopy revealed

    some irreversible fouling on the chemical cleaned membrane. Thus caustic cleaning did not completely

    remove all foulants from the membrane surface and the membrane surface hydrophobicity and zeta

    potential changed correspondingly. The temporary enlargement of the membrane pores due to caustic

    cleaning subsequently led to notable changes in the rejection of inorganic salts (measured by conductivity)

    and carbamazepine. By contrast, the impact of chemical cleaning on the rejection of the negatively

    charged sulfamethoxazole was negligible. This is because the rejection of sulfamethoxazole is predominantly

    governed by electrostatic repulsion between the compound and the negatively charged membrane

    surface and thus is not significantly influenced by any enlargement of the membrane pores.

Authors


  •   Simon, Alexander R. (external author)
  •   Price, William E.
  •   Nghiem, Long D. (external author)

Publication Date


  • 2013

Citation


  • Simon, A. R., Price, W. E. & Nghiem, L. D. (2013). Changes in surface properties and separation efficiency of a nanofiltration membrane after repeated fouling and chemical cleaning cycles. Separation and Purification Technology, 113 42-50.

Scopus Eid


  • 2-s2.0-84877352620

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1733&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/727

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 42

End Page


  • 50

Volume


  • 113

Place Of Publication


  • United Kingdom

Abstract


  • The aim of this study was to evaluate the changes in membrane surface properties and solute separation

    by a nanofiltration membrane during repetitive membrane fouling and chemical cleaning. Secondary

    treated effluent and model fouling solutions containing humic acids, sodium alginate, or silica colloids

    were used to simulate membrane fouling. Chemical cleaning was carried out using a commercially available

    caustic cleaning formulation. Carbamazepine and sulfamethoxazole were selected to examine the

    filtration behaviour of neutral and negatively charged organic compounds, respectively. Results show

    that the impact of membrane fouling on solute rejection is governed by pore blocking, modification of

    the membrane surface charge, and cake enhanced concentration polarisation. Caustic cleaning was effective

    at controlling membrane fouling and membrane permeability recovery was slightly more than 100%.

    In good agreement with the literature, the high membrane permeability recovery observed here suggests

    that caustic cleaning could lead to temporary enlargement of the membrane pores. In addition, microscopic

    observations based on scanning electron microscopy and energy dispersive spectroscopy revealed

    some irreversible fouling on the chemical cleaned membrane. Thus caustic cleaning did not completely

    remove all foulants from the membrane surface and the membrane surface hydrophobicity and zeta

    potential changed correspondingly. The temporary enlargement of the membrane pores due to caustic

    cleaning subsequently led to notable changes in the rejection of inorganic salts (measured by conductivity)

    and carbamazepine. By contrast, the impact of chemical cleaning on the rejection of the negatively

    charged sulfamethoxazole was negligible. This is because the rejection of sulfamethoxazole is predominantly

    governed by electrostatic repulsion between the compound and the negatively charged membrane

    surface and thus is not significantly influenced by any enlargement of the membrane pores.

Authors


  •   Simon, Alexander R. (external author)
  •   Price, William E.
  •   Nghiem, Long D. (external author)

Publication Date


  • 2013

Citation


  • Simon, A. R., Price, W. E. & Nghiem, L. D. (2013). Changes in surface properties and separation efficiency of a nanofiltration membrane after repeated fouling and chemical cleaning cycles. Separation and Purification Technology, 113 42-50.

Scopus Eid


  • 2-s2.0-84877352620

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1733&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/727

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 42

End Page


  • 50

Volume


  • 113

Place Of Publication


  • United Kingdom