الفهرس 
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Abstract
Capacitive deionisation (CDI) is an electrosorption desalination process that has many advantages as an alternative desalination technology due to its low energy consumption less environmental pollution and low fouling potential. This thesis explores various factors that have significant impacts on CDI operational performance in desalination and addresses technical challenges faced by CDI technology when it is applied for inland water supply. The main objective of this thesis is to provide an evaluation of the desalting performance of CDI technology, and to explore the possibility of actual site operation for inland brackish water desalination The research investigated the effect of operational conditions on CDI electrosorption efficiency and energy consumption, identified ion selectivity in multi-ionic solutions and investigated the effect of dissolved reactive silica on the treatment efficiency. The electrosorption removal efficiency was inversely related to solution temperature, initial total dissolved salts (TDS) and the applied flow rate. It was observed that ions with greater charge were more easily adsorbed onto the electrode surface. For ions having the same charge, those with smaller hydrated radii were more easily adsorbed onto the electrodes. It was found that the dissolved silica was not removed by CDI process; no silica fouling was found. Next, a portable prototype capacitive deionisation unit was used first time in the Northern Territory, Australia, to remove salt from the brackish groundwater. The CDI unit demonstrated sufficient salinity and hardness removal ability at the remote brackish water source. The portable CDI unit proves to be a viable alternative solution to other brackish water treatment, in communities in remote areas where building a reverse osmosis treatment plant is not practical In this research, fouling, scaling and cleaning of the capacitive deionisation unit with activated carbon electrodes were systematically investigated for the first time in the lab and in the field at two Australian locations. It was found that the higher the TOC concentration in the CDI feed solution, the more the reduction of salt removal efficiency, the decline in the production rate and the associated energy consumption Dissolved organic matter was the main cause of electrode fouling, as it blocked the activated carbon pores and reduced their electrosorption capacity. Ca and Mg had no noticeable effect on the CDI treatment performance. However, Fe did have an effect on II CDI electrode fouling. Alkaline and acid cleaning solutions were able to restore the CDI performance. The data and results obtained in this research can be used as guide for the on-site operation of this emerging technology charge efficiency is an important property of CDI that affects the consumption of electrical energy. charge efficiency is directly related to flow rate and applied voltage and inversely related to the feed solution concentration. from the charge efficiency results, it can be concluded that 30% to 35 % of the electrical energy is wasted in desorption of co-ions from the electrode surface during the desorption stage. The isotherm results are well represented by the Langmuir model. The electrosorption of NaCl onto activated carbon electrodes followed the Lagergren kinetic equation Thermodynamic analyses confirmed that the electrosorption of NaCl onto the CDI electrodes was mainly a physisorption process.