Authors: Linda Zou, Haibo Li and Mohamed Mossad
Presenter: Linda Zou, Professor, University of South Australia
Presentation: Future Separation Technologies, Wednesday, September 7, 5:00-5:30 pm, M+1+2+3
For inland communities the only reliable water resource is groundwater and limited surface river water but much of this contains salt to varying degrees. To produce drinking water (< 500 mg/L salinity) it is necessary to remove the salt using a desalination process. Typically, reverse osmosis (RO) membrane technology is utilized. However, RO desalination requires extensive use of energy which results in high operational costs, discharge of large volumes of brine and long-term membrane replacement costs. Silica fouling of membranes is also a major challenge for RO in regional Australia due to the naturally high levels of silica present in groundwater. These natural high levels of silica cause silica fouling of membranes, which is extremely difficult to remove once formed, due to the polymerisation reaction that takes place on the membrane surface. In order to remove salt from inland brackish water, it needs another uncomplicated technology which offers the advantages of easy maintenance, high efficiency and a resistance to high silica concentrations in brackish ground water. Capacitive deionisation (CDI) has been evaluated in this study to treat synthetic solutions and actual brackish ground water. The bench scale CDI and MCDI units were designed and fabricated using different carbon electrodes, such as activated carbons and carbon nanotubes, the salt removal efficiency of these electrode materials avoid silica fouling were assessed and reported. In addition, a commercial CDI unit was trialed in the lab using synthetic brackish water as feed. It was found that Capacitive Deionization is a suitable technology to remove TDS from brackish water. It has the advantages of being not affected by silica scaling. It is an alternative to RO in producing drinking water in inland area.
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