Abstract:A novel Fe/Al/Ca-bearing composite defluorination agent was prepared with by-product of waste lithium ion batteries during removal of iron and aluminum. The results show that defluorination efficiency from c(F-)=2.94 g/L synthetic wastewater is 98% above and adsorption capacity of defluorination agent is about 144 mg/g under the optimum conditions including dosage of defluorination agent of 20 g/L, initial pH value of 3-4, temperature of 60 ℃, and adsorbing time of 30 min. Defluorination agent was characterized by SEM, EDS and XRD. Main phases of composite defluorination agent are rodlike calcium sulfate and amorphous state of ferric and aluminum hydrolysis products. Calcium fluoride and sodium hexafluoroaluminate are generated in the residue after fluoride removal.