▎ 摘　　要

NOVELTY - Preparing lanthanum-modified graphene oxide comprises dissolving the lanthanum chloride in oxidized graphene dispersion liquid to obtain the mixed solution, where the graphene oxide and lanthanum chloride mass ratio is 1:0.3-0.5, subjecting the resultant mixed solution into water bath temperature oscillation, heating the mixed liquid in the water bath at constant temperature, shaking the mixture, centrifuging to obtain precipitate, washing the precipitate, separating and freeze-drying to obtain lanthanum-modified graphene oxide. USE - The modified graphene oxide is useful for preparing phosphate ion grid (claimed). ADVANTAGE - The graphene oxide has strong structure stability and is easy to change. DETAILED DESCRIPTION - Preparing lanthanum-modified graphene oxide comprises (i) placing the graphene oxide in deionized water and ultrasonically dispersing to obtain oxidized graphene dispersion liquid; (ii) dissolving the lanthanum chloride in oxidized graphene dispersion liquid to obtain the mixed solution, where the graphene oxide and lanthanum chloride mass ratio is 1:0.3-0.5; (iii) subjecting the resultant mixed solution into water bath temperature oscillation; and (iv) heating the mixed liquid in the water bath at constant temperature, shaking the mixture, centrifuging to obtain precipitate, washing the precipitate, separating and freeze-drying to obtain lanthanum-modified graphene oxide. INDEPENDENT CLAIMS are also included for: (1) a lanthanum-modified graphene oxide is prepared by above mentioned method; and (2) preparing phosphate ion grid comprising (i) mixing the framework material and the polyethylene glycol, stirring uniformly, where the framework material and polyethylene glycol volume ratio is 44-54:1, (ii) adding the lanthanum-modified chitosan and lanthanum-modified graphene oxide into the mixture, dispersing, where the mass ratio of the lanthanum-modified graphene oxide and the lanthanum-modified chitosan is 0.1-0.5:0.8-2, and (iii) adding the crosslinking material into the mixture, stirring and freezing to obtain phosphate ion grid, where the volume ratio of the cross-linked material to the framework material is 22-27:44-54.