Super Activated Carbon Electrodes For Capacitive Deionization Technology

Water is not only essential for living organisms, but also fundamental resources in industries and agriculture. Due to progressive industrialization and expansion of irrigation agriculture, the use of fresh water is increasing. The rapid increase of the global population and the non-uniform distribution of fresh water around the world have motivated research into getting water from seawater or brackish water since they account for 98% of the Earth's water. The most widely used processes for desalination include thermal process, reverse osmosis, electrodialysis and so on. However, above methods were hampered by either high consumption or second pollution. Capacitive deionization (CDI) is an energy-effective, low-pressure and environmental friendly technology which removes ions by electrostatic adsorption. It bases on double layer theory and only needs 1-2â…¤operating voltage.Super activated carbon as electrosorptive electrode material for CDI has been explored, and the effects of the composition of electrode and operating conditions have been studied. The results show that the composition of electrode and operating conditions such as voltage, electrode spacing and solution flow rate all have effects on desalination performance.Cation-exchange membranes and anion-exchange membranes have been decorated on the surfaces of cathode and anode respectively to assemble into membrane capacitive deionization (MCDI), which made desalination efficiently and economically. At high solution concentration, the amount of salt removed from the water increases by 50%, at the same time, the current efficiency of the composite electrodes with ion-exchange membranes increases by 17%. The recycling performance of the composite electrodes is also greatly improved.Activated carbon/expended graphite (EG/AC) composites have been prepared and desalination performance has been discussed. Expanded graphite can provide good environment for activated carbon particles to touch well with each other and improve the conductivity of electrodes. So the desalination performance of composite electrode is increased.