Preparation Of LiFePo₄/Amino Graphene/Titanium Mesh Composite Electrode Materials And Application Of Extraction,Concentration And Recovery Of Lithium From Aqueous Solution

LiFePO₄（LFP）was prepared by sol-gel method.LiFePO₄/amino grapheme/titanium mesh composite electrode（LFP/GNs/Ti）was prepared by coating method.The morphology,microstructure and composition of were characterized by XRD,FE-SEM,XPS and FT-IR.LFP was uniformly coated at the grapheme with nano spherical particles,and the average size was about 20 nm.The separation behaviors of Li⁺at LFP/GNs/Ti was investigated in salt solution by an electrochemical assisted adsorption and deionization desorption method.The effects of p H,time,initial concentration and potential on the recovery of Li⁺were investigated.In the potentiostatic adsorption process,the adsorption of Li⁺at LFP/GNs/Ti conform to the quasi second order kinetic model.The adsorption capacity for Li⁺was 35.8 mg·g^-1in the conditions including-0.3 V,p H 6,25℃and 5 h(initial concentration of Li⁺:75mg·L^-1).In the coexistence of 1:1 Na⁺,K⁺,Ca²⁺and Mg²⁺,LFP/GNs/Ti still showed good selectivity for Li⁺adsorption.Cyclic voltammetry method was used in the desorption process in potential of+0.8～-0.8 V,the desorption rate of Li⁺from LFP/GNs/Ti（Li⁺）could reach to 90%by 300 cycles in p H 4,0.1 M NH₄Cl/HCl at25℃.Then,the LFP/GNs/Ti could be regenerated.Moreover,an electrodialysis device was set up to study the membrane concentration of Li⁺desorption solution.The effect of different current densities on the concentration of Li⁺was investigated.The results showed that the concentration could reach to 14times of the original at current density of 30 m A·cm^-2 and reaction time of 50 min.