| It has always been a hot topic to remove phosphorus which is the major cause of eutrophication.In this paper,the active rice husk carbon,which was boiled by CO2,was used as the raw material.Then,lanthanum modified magnetic rice husk biochar with preferable phosphorus removal effect and easy magnetic separation was prepared by solvothermal and co-precipitation method.The adsorbent was characterized by FSEM,BET,XRD,FTIR and VSM.During the preparation by different methods,it was found that the adsorbents,MC-Lax,prepared by the combination of co-precipitation and solvothermal method exhibited more stable and excellent adsorption performance.The characterization results showed that Fe3O4 spherical particles,La?OH?3 rod were uniformly distributed on the surface and pores of biochar.VSM results showed that MC-Lax had good magnetic separation performance.XRD showed that the phosphate adsorption was mainly due to the ligand exchange between La?OH?3 and phosphate.Later,the phosphates adsorption performance was studied by batch experiments and the mechanism was investigated by XRD and FTIR.A preliminary study of actual wastewater treatment and adsorption/desorption cycles were also discussed.1.In the initial pH=2–11,the adsorption capacity of the adsorbents first increased and then decreased and reached highest at pH=5?11.55?17.98?25.11mg/g for MC-La0.1?MC-La0.2?MC-La0.4 respectively?.The low removal rates at pH=2 may due to the La leakage.2.The coexistence of F-inhibited the adsorption strongly.HCO3-and humic acid at low concentration had little effects on phosphate removal,while exhibited obvious inhibition at high concentration.3.The adsorption reaction of phosphorus by MC-Lax accorded with the second-order kinetic model and the Freundlich isotherm model.4.It is found that the mechanism of MC-Lax on phosphate removal was mainly due to the ligands exchange of to form LaPO4 dentate complexes.5.In the process of real wastewater treatment,MC-Lax showed high adsorption efficiency on phosphate and the adsorption capacity remained 71%-83%after fourth regeneration.Overall,the results of this study showed that the La-modified magnetic rice husk biochar exhibited high separation potential good phosphate adsorption performance,which had a certain practical application prospect. |
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