The Research Of Electrosorption Of Alkali/Alkaline Earth Metal Ions With Biomass Carbon-based Electrode

In recent years,the electrosorption technology has been developed rapidly due to its advantages,such as low energy consumption,simple operation and no secondary pollution.In this work,different kinds of biomass carbon materials were prepared by using the biomass sources as raw materials with extensive source and low cost.A series of electrodes were synthesized by incorporating the biomass carbon materials with other reagents.Then the electrosorption of alkali/alkaline earth metal ions on biomass carbon-based electrodes has been systematically studied.?1?A variety of biomass carbon materials based on pine needle?PN and APN?and pomelo?PCA and APCA?peel were prepared by low temperature hydrothermal-high temperature?activation?carbonization and low temperature hydrothermal-freeze drying-high temperature?activation?carbonization.The prepared biomass carbon materials were characterized by SEM,specific surface area and pore size,XRD,Raman,cyclic voltammetry and electrochemical impedance spectroscopy analysis.The results showed that the prepared activated carbon materials had three-dimensional porous structures,large specific surface area and total pore volume,and amorphous structure with a certain degree of graphitization and conductivity.The activating process is favorable to increase the specific surface area.?2?The biomass carbon-based electrodes were prepared and their electrosorption behavior of alkali/alkali earth metal ions from mono-component and multi-component solution and recycling performance were investigated.The results showed that the adsorption capacity of electrodes prepared with activated biomass carbon materials was much higher than that with inactivated materials.The adsorption capacity of bivalent ions was higher than that of univalent ions when the same electrodes used.The alkali/alkaline earth metal ions adsorption capacities of electrodes were affected by hydration radius and ion radius,and the adsorption behaviors as follows:Sr²⁺>Ca²⁺>Mg²⁺>Cs⁺>Rb⁺>K⁺>Na⁺>Li⁺.In addition,the electrosorption voltage and initial concentration of ions had significant effects on the adsorption capacity which increased with the increasing of voltage and initial concentration of ions.The electrodes displayed good recycle and regeneration performance.?3?Titanium dioxide?anatase and rutile?doped composite electrodes derived biomass carbon materials were prepared and employed to investigate the electrosorption behavior of alkali/alkaline earth metal ions from the aqueous solutions.Compared to biomass carbon-based electrodes undoped,the titanium dioxide doped electrodes had higher adsorption capacity and needed shorter time to reach adsorption equilibrium.However,the adsorption capacity of alkali/alkaline earth metal ions was in the same order as biomass carbon-based electrodes undoped.?4?The electrosorption performance of alkali metal ions on the ammonium molybdopho-sphate doped composite electrode derived APCA was investigated comprehensively.The results showed that this composite electrode revealed good selectivity for Rb⁺and Cs⁺due to the addition of AMP.And the adsorption capacity did not decrease obviously with the increase of K⁺concentration in the multi-component solution which indicated that chemical adsorption existed between the electrodes and Rb⁺?Cs⁺ions.