Short-term adhesion and long-term biofouling testing of polydopamine and poly(ethylene glycol) surface modifications of membranes and feed spacers for biofouling control

The role of cell-surface interactions in bacterial initial adhesion and consequent biofilm formation on nanofiltration/reverse osmosis membranes

“…Likewise, the surface modification of spacers used in NF/RO processes have also been targeted for surface functionalization as a means for controlling biofouling [92,97,98]. Detailed descriptions of existing surface modification techniques for the creation of antibacterial surfaces are well described in a recent review [99].…”

“…Different membrane materials will have different affinities for different bacterial species translating into different amounts of bacteria adhered [67,70,117]. However it is notable that several biofouling studies show that flux reduction and feed pressure drop increase, is generally independent of membrane surface properties [9,30,114,118], and hence possibly independent of differences in the pioneer bacteria. In contrast, a recent study on biofouling in cooling towers showed that the microbial community composition can be greatly affected by the characteristics of initial adhesion of bacterial cells [119].…”

“…It is generally accepted that initial bacterial adhesion is a key part of the biofilm development process. However there is an increasing body of evidence suggesting that the rate of bacterial adhesion is not predictive of the extent of biofilm formation [9]. Experimental studies where both initial adhesion rate and biofilm formation rate were measured under comparable conditions are rarely found in the literature, showing a need for further investigation of the relationship between initial adhesion and biofilm formation.…”

Hydrogel-coated feed spacers in two-phase flow cleaning in spiral wound membrane elements: A novel platform for eco-friendly biofouling mitigation

“…act similarly to chemical cleaning, the first layer of bacterial cells might be killed, but the material from dead bacteria provides nutrients for subsequent bacterial growth (Araújo et al 2012a). For polydopamine and polydopamine-g-poly(ethylene glycol) coatings, although batch adhesion tests using bacterial solutions or proteins under static conditions showed good anti-biofouling properties, long-term and continuous biofouling experiments demonstrated poor biofouling inhibition (Miller et al 2012). The results might be related to instability of those polymers during long-term experiments.…”

“…The results might be related to instability of those polymers during long-term experiments. The potential of more stable hydrophilic coatings to facilitate membrane cleaning is therefore still promising (Miller et al 2012). Moreover, polydopamine is amphoteric and differently charged in acidic and basic environments (Liu et al 2014), and the results suggest that surface charge affects the early attachment of biofouling on the feed spacer surface, since electrostatic interactions between surfaces and the charged outer layer of cell membranes of fouling organisms can play a role.…”