Preparation method of lanthanum-loaded artificial wetland filler for deep phosphorus removal

A preparation method of a lanthanum-loaded artificial wetland filler for deep phosphorus removal comprises the following steps: preparing an artificial wetland pre-filler which is prepared from the following components in parts by weight: 65-75 parts of lake sediment, 10 parts of canna biomass powder, 10-20 parts of soluble starch/attapulgite and 5-10 parts of magnesium carbonate; the method comprises the following steps: magnetically stirring a lanthanum chloride solution with the concentration of 0.02-0.1 mol.L at 25-85 DEG C for 5-10 minutes, adding a constructed wetland pre-filling material, then adding magnesium salt, carrying out ultrasonic treatment for 10-30 minutes, and continuously stirring for 10-20 minutes to obtain a mixed solution; and dropwise adding a sodium bicarbonate solution into the mixed solution, continuously stirring, aging for 15-30 minutes, cooling, carrying out suction filtration, washing with distilled water, and drying to obtain the lanthanum-loaded artificial wetland filler