Recognitions And Removal Efficiency Of Plant Based Carbon Materials Towards Al(?) And Fe(?) In Rare Earth

Rare earth elements are an important strategic resource.However,trace impurity in rare earth materials can seriously damage the performance of rare earth materials.the effective methods of removal these impurities from rare earth elements are of great significance.As a n excellent adsorbent,carbon materials become the preferred adsorbent to remove the impurities in rare earth.Depend on the excellent adsorption capacity,nitrogen-containing activated carbon have received considerable attention and researches.Pine cone,pine needle and lotus root have a wide range of sources in China,while the nitrogen and pore system contained are rich.In this paper,the nitrogen-containing activated carbons,AC_PC,AC_PN and AC_LR,was synthesized using pine cone,pine needle and lotus root as raw material and KOH as activator.According to FT-IR,elemental analysis and surface area analyzer,investigated the removal ability of these samples toward Fe???and Al???in rare earth.AC_PC,AC_PN and AC_LR have well-developed internal pore structure and abundant nitrogen content.The BET specific surface area of AC_PC-500-3,AC_PN-700-3,AC_LR-600-3R-600-3 and AC_LR-400-3R-400-3 are 294.5,596.4,347.32 and 68.44 m²/g,respectively.The nitrogen content of them are 0.71%,9.98%,0.72%,1.65%,respectively.Rely on well-developed internal pore structure and abundant nitrogen-containing functional groups,AC_PC,AC_PN and AC_LR have possesses strong adsorption affinity and excellent recognition selectivity for Fe???and Al???.A series of experimental results suggested that the carbon materials which synthesized at different conditions showed different adsorption properties.The adsorption capacity of AC_PC-500-3?AC_PN-700-3 and AC_LR-600-3 toward Al???are 6.01 mg/g?3.92 mg/g and 4.44 mg/g,respectively.The adsorption capacity of AC_LR-400-3 towards Fe???was 25.89 mg/g.The adsorption behavior was in accord with the two order kinetic model,and all of them were Freundlich monolayer adsorption.The adsorption capacity was greatly affected by pH,temperature and the dosage of absorbent.The adsorption capacity of selected samples increases with the increase of pH and dosage of absorbent.But the adsorption capacity to Fe???was increase with the temperature goes up,while Al???was opposite.The selectivity coefficient of AC_PC-500-3?AC_PN-700-3N-700-3 and AC_LR-600-3R-600-3 towards Al???with respect to La???was 8.83?7.89 and 8.63,respectively,while AC_LR-400-3R-400-3 towards Fe???was8.9.The removal efficiency of AC_PC-500-3,AC_PN-700-3,and AC_LR-600-3 for Al???was 96.88%,95.97%,96.5%,respectively.The removal efficiency of AC_LR-400-3R-400-3 to Fe???was 99.61%.The results of study manifested that AC_PC-500-3,AC_PN-700-3,AC_LR-600-3 and AC_LR-400-3 possesse better regeneration ability and reusability.