Biofouling of reverse osmosis (RO) membranes used in water treatment processes is a major obstacle to more widespread use of this technology.
In this work by researchers at Kobe University in Japan, a commercial RO membrane (Nitto Denko ES-20) was modified by adsorption of copper hydroxide (Cu(OH)2) particles, to improve the anti-biofouling properties of the membrane.
The adsorption of Cu(OH)2 particles was confirmed by field emission scanning electron microscopy and energy-dispersive spectroscopy. The proportion of adsorbed Cu(OH)2 particles was measured by flame atomic absorption spectrophotometry.
The antibacterial properties of the modified membranes were evaluated by a shake flask test with Escherichia coli, while the anti-adhesion properties were evaluated by an immersion test using Pseudomonas putida.
The Cu(OH)2 modified membranes showed good antibacterial activity compared with the unmodified membrane. The antibacterial activity was attributed to release of Cu2+ ions from Cu(OH)2 particles adsorbed to the membrane.
The anti-adhesion properties of the membrane were improved by Cu(OH)2 modification. This is attributed to an increase in the hydrophilicity and negative charge density of the membrane surface.
The membrane modified with Cu(OH)2 particles showed high anti-biofouling performance, attributed to a combination of antibacterial and anti-adhesion effects.
