AN ACTIVATED CARBON/ZN-BASED METAL-ORGANIC FRAMEWORK COMPOSITE ELECTRODE FOR ENHANCED SALT REMOVAL BY CAPACITIVE DEIONIZATION

The globally demand of acquiring clean water is increasing daily due to population growth,water contamination, decreasing limited availability of freshwater sources and especially climate change, Tang et al. (۲۰۱۹). Therefore, numerous processes including thermal processes, membrane-based pressure-driven processes and electrochemically-driven processes have been employed for water desalination. All these processes and technologies have their own limitations such as high energy consumption, membrane fouling, wastewater disposal and etc., Choi et al. (۲۰۱۹). Low energy consumption, low environmental impact and simple equipment structure are some of the advantages of capacitive deionization (CDI) that currently is very efficient for low to medium saline water (brackish water), Porada et al. (۲۰۱۳), Suss et al. (۲۰۱۵). CDI is characterized by the removal of charged ionic species from aqueous solutions via electrostatic or electrochemical interactions. A CDI cell generally consists of two porous electrodes which saline water flows through them and cations and anions adsorbed on the active surface of the electrodes; thus a high accessible surface area, hydrophilisity and excellent electrochemical performance are the features the electrodes must have, Porada et al. (۲۰۱۳),Tang et al. (۲۰۱۹). For this purpose the most common and widely used material is active carbon (AC). Some additives like metal oxides such as ZrO۲, Fateminia et al. (۲۰۲۱), N-doped materials such as polyaniline (PANI), Fateminia et al. (۲۰۲۱), also metal-organic frameworks (MOFs) such as Cu- BTC, Cen et al. (۲۰۲۰), can greatly enhanced and/or fabricate some properties for carbon electrodes.