Abstract
Capacitive deionization (CDI) is greatly recommended as a desalination process for its eco-friendly and low energy consuming technique in removing salt ions (NaCl) from salty water. This study reports a Zeolitic Imidazolate Framework-8/Graphene (ZIF-8/G) nanocomposite modified electrode performance in CDI technology. Based on its promising features, like large surface area and good electric conductivity, graphene is an adequate electrode. Interestingly, ZIF-8 is homogeneously well intergrown on the surface of graphene. Hence, electrochemical performance such as electrical conductivity and cyclic voltammetry in CDI unit were examined, and characteristics like the morphology, identification and determining the structure of the prepared materials were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR). As an adsorbent, the prepared ZIF-8/G nanocomposite exhibits the best adsorption capacity about 141.6037 F/g higher than each individually and great electrical conductivity about 672 μs/cm. The high adsorption specific capacity and good reusability of the ZIF-8/G nanocomposite suggests that it can be applied as novel adsorbents showing attractive potential for the CDI technique.
Highlights
The crisis of water scarcity has intensified in the field of domestic consumption, but it has affected the agricultural and industrial sectors which make up the bulk of the consumption
The morphology of nanomaterial was observed by a scanning electron microscope (VEGA\\TESCAN)
The electrochemical performance of the electrodes was identified by cyclic voltammetry (CV) autolab Metrohm device, at four scan rates 5, 20, 50, 100 mV/s and voltage range −1 to 1
Summary
The crisis of water scarcity has intensified in the field of domestic consumption, but it has affected the agricultural and industrial sectors which make up the bulk of the consumption. Capacitive deionization (CDI) is an electrochemical research field, with primary applications in brackish water desalination and wastewater purification. The certain amount of specific surface area and specific capacity may lead to significant salt adsorption on electrode (Fig. 1) This process forms the charge half-cycle and is the desalination step. Graphene is a carbon material with a huge theoretical specific surface area of 2600 m2/g at room temperature (Stoller et al 2008) These intriguing properties enabled graphene to be a promising potential for a graphenebased material for CDI electrode (Wang et al 2012). The nanocomposite was prepared in a sequential step-bystep process, consisting of the following steps; 1 g graphene oxide (as a basic layer) was dispersed in zinc sulfate (100 mmol) solution under ultrasonic treatment for 20 min. 2-methyl-imidazole (100 mmol) was added to the re-dispersed GO nanoparticle suspension to form ZIF-8 coating layer on the surface of GO, and the suspension was ultrasonically treated
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