Design And Preparation Of Porous Graphene Electrode And Its Capacitive Desalination Performance

With the growth of the population and the continuous pollution of the environment,the shortage of water has become an urgent problem.Capacitive desalination?CDI?has many advantages as a kind of water treatment technology,such as simple operation,low energy consumption,no-secondary pollution.Electrode material is the key of the capacitor desalination technology,determining the efficiency of desalination,recycling performance and industrial application.Carbon materials are very popular in electrochemical applications due to their good electrical properties and mechanical properties.Especially,graphene,a typical two-dimensional structure of carbon material that owns large theoretical surface area,excellent electrical conductivity,excellent chemical stability and controllable structural properties,has found huge potentials in capacitive desalination applications.We have proposed a novel method to prepare the graphene electrode in mild and environment-friendly manner.Sodium dodecyl sulfate surfactant surfactant and directly freeze-drying were used to achieve better dispersion of GO sheets,making a high specific surface area and favorable size distribution as CDI electrode materials.The properties of SRGO have been investigated deeply and systematically by transmission electron microscopy?TEM?and scanning electron microscopy?SEM?observations,X-ray powder diffraction?XRD?,Elemental distribution analysis?EDS?,Brunauer-Emmett-Teller?BET?adsorption isotherm,and Raman spectra.The aim of this method is to get a three-dimensional porous graphene electrode which with ultrahigh performance for CDI applications.SRGO exhibited promising CDI performance with a superior electrosorptive capacity of 5.38 mg·g^-1 and the excellent recyclability of 64 min.And the salt removal efficiency of the SRGO is 15.85%which was improved by 30%compared to that of the initial RGO.This work may open the door for a variety of applications of SRGO such as in biotechnology,supercapacitor and water desalination.We have prepared three-dimensional graphene with porous structure.The chlorella was used as template to hold the graphene oxide to obtain a rough surface assisted with freeze-drying treatment.After high-temperature calcination,3D graphene material with the controllable pore size distribution was obtained.The specific surface area of the template-prepared graphene is 745.06 m²·g^-1.The specific capacitance was 307.8 F·g^-1 in 0.5 M NaCl solution,indicating the potential application of this material in capacitive desalting.Moreover,a new type of electro-adsorption liquid treatment device is designed for capacitor desalination.The device has the advantages of simple equipment and simple operation,which combined with the advantages of flow electrode adsorption and membrane electrode adsorption.The introduction of anion and cation exchange membrane improve potentially the performance of the cell.