Corrigendum to “A physical impact of organic fouling layers on bacterial adhesion during nanofiltration” [Water Res. 67 (2014) 118–128] (S0043135414006411) (10.1016/j.watres.2014.09.012))

R. Heffernan, O. Habimana, A. J.C. Semião, H. Cao, A. Safari, E. Casey*

*Corresponding author for this work

Research output: Contribution to journalComment/debate

1 Scopus citations


The authors would like to inform that, due to a previously unforeseen conversion error in the JPK Atomic Force Microscopy software, a number of corrections to the published data were found necessary. The correct text is given below. The authors regretfully apologise for any inconvenience caused. 2.11 Atomic Force Microscopy (Methods) Values of the energy dissipated during approach and retraction of a probe (Fig. 3) through the organically fouled samples had been erroneously outputted as voltage (V) rather that force (N). After applying a conversion factor to correct this data the magnitudes of energy dissipated were no longer significantly different on a ‘per micron’ scale (J/μm). To show the physical effect of the fouling layers, it was now more appropriate to consider the magnitude of energy dissipated to reach the membrane's surface (J). For clean membrane samples the force values obtained through AFM were not scaled (representing the total repulsion of the membrane's sample). For organically fouled membranes the energy dissipated upon approach was linearly extrapolated (assuming an average layer thickness of 25 μm, as seen from confocal microscopy) to estimate the magnitude of energy dissipated in approaching the membrane surface through the layer. 3.4 Atomic Force Microscopy (Results) Approaching the clean membrane's surface required a small amount of energy (10−16 J) as the probe was repelled by the membrane's surface charge. With the addition of the fouling layers, however, the probe was still more than 20 μm away from the membrane's surface and thus would not have felt the membrane's repulsion; the energy dissipated is hence related to the resistance to penetration of the relatively dense fouling layer itself. A much greater magnitude of energy (10−14 J) is therefore required to penetrate through the 25 μm thick fouling layers to reach the membrane's surface (Fig. C1). This suggests that the layers may act as an obstacle resisting bacterial penetration leading to a lower rate of bacterial adhesion onto the NF membrane surface. On average more energy was dissipated when penetrating the HA layer (4.27 × 10−14 J) than the AA layer (2.35 × 10−14 J) which would therefore suggest that bacterial adhesion would occur to a greater extent within the AA layer, as it is more likely that bacterial cells would penetrate the layer. This difference is, however, of a much smaller magnitude than that seen between fouled and clean NF90 membranes. The energies of retraction, from the membrane's surface and from the fouling layers, were no longer significantly different. Fig. C1: Population density diagram of the energy dissipated during approach of a triangular silicon nitride Atomic Force Microscopy probe through the top 0.5–1 μm of fouling layers of humic acid and alginic acid on NF90 membranes, or within 0.5 μm of an unfouled salt control sample. 50 independent measurements were taken from 8 membrane samples for each foulant and corrected to a distance to reach the membrane's surface for comparative purposes. Energy dissipated is presented on a log10 scale.[Figure presented] Resultant Corrections Abstract The energies dissipated when attempting the fouling layers and onto the clean membranes are now 10−14 J and 10−16 J respectively. 3.5 Bacterial Adhesion onto Fouled Membranes The dissipated energies stated for AA and HA fouling layers are now 4.27 × 10−14 J and 2.35 × 10−14 J respectively.

Original languageEnglish
Pages (from-to)412-413
Number of pages2
JournalWater Research
StatePublished - 15 Oct 2015
Externally publishedYes


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