Membrane scaling, where salt crystals such as CaSO4 (gypsum) or CaCO3 grow on the membrane surface, is a significant problem in brackish groundwater desalination. Typically, anti-scaling chemicals are added to the feed stream to prevent this phenomenon. Alternatively, in CaCO3 scaling waters, the pH of the feed stream is adjusted through the addition of strong acids to prevent CaCO3 mineral formation.  Electrically conducting carbon nanotube-polymer composite tight nanofiltration      membranes have been demonstrated to prevent the growth of biofilm bacteria. These membranes have similar transport characteristics to commercially available membranes, and can be easily and cheaply fabricated using standard wet chemistry methods. Here, we report the use of these membranes in significantly slowing the growth of inorganic crystals after applying an external electrical bias to the membrane surface. The impact of the charge magnitude and sign is discussed, along with a proposed mechanism that is responsible for the observed phenomenon.

Mineral scale inhibition using electrically conductive tight nanofiltration membranes

246th National Meeting (2013)

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