Porous carbon materials derived from biomass waste as efficient electrodes for capacitive deionization desalination

The scarcity of freshwater has attracted the attention of countries around the world. Capacitive deionization (CDI) is a burgeoning green desalination technology with low price and high efficiency. The properties of the CDI electrodes directly affect the deionization efficiency. It is a hot spot of CDI technology research to develop electrode materials with higher adsorption capacity, better sustainability and lower cost. On this purpose, porous carbon materials derived from corncobs, cornstalks and waste cigarette butts have been firstly used as electrodes for CDI desalination in this paper. Eight derived materials have been successfully prepared through carbonization and activation. The morphology characteristics and electrochemical performance of the materials have been examined. Their desalination performance has been investigated. The results show corncobs activated at 800 degrees C (CBC-800) have the best properties with a specific surface area of 1,201.9 m2 center dot g-1 and pore size of 1.7268 nm. The CBC-800 electrode also possesses a high specific capacitance of 141.4 F center dot g-1 and low inner resistance. The salt adsorption capacity is 19.2 mg center dot g-1 and the charge efficiency is 60.3% in a 3,000 mg center dot L-1 NaCl solution at 1.2 V. CBC-800 is expected to be an efficient electrode material for CDI applications.