▎ 摘　　要

NOVELTY - Cerium complex (I) is new. The crystal of (I) belongs to the triclinic system, has P-1 space group, and unit cell parameters of (a of 5.5405(2) Angstrom , b of 13.7558(6) Angstrom , c of 18.1753 (8) Angstrom , alpha of 72.622(1) degrees , beta of 85.278(1) degrees , and gamma of 80.859(1) degrees ). USE - (I) is useful in preparing magnetic recoverable cerium complex/graphene oxide/iron(II,III) oxide ternary composite as excellent photocatalyst for treating methylene blue dye wastewater (claimed). ADVANTAGE - The magnetic recoverable cerium complex/graphene oxide/iron(II,III) oxide ternary composite: can quickly catalyze and degrade methylene blue dye in aqueous solution under sunlight irradiation condition; degradation rate reaches 90.2% after degrading for 120 minutes to ensures dye solution is near colorless; can be recycled in the range of pH of 3-9; and still has excellent catalytic activity after repeated use for four times. DETAILED DESCRIPTION - Cerium complex of formula ((Ce2(TCPB)2(G)(H2O))n) (I) is new. The crystal of (I) belongs to the triclinic system, has P-1 space group, and unit cell parameters of (a of 5.5405(2) Angstrom , b of 13.7558(6) Angstrom , c of 18.1753 (8) Angstrom , alpha of 72.622(1) degrees , beta of 85.278(1) degrees , and gamma of 80.859(1) degrees ). TCPB = 1,3,5-tri(4-carboxyphenoxy)benzene; G = dimethylformamide; and n = degree of polymerization i.e. integer. INDEPENDENT CLAIMS are also included for: (1) magnetic recoverable cerium complex/graphene oxide/iron(II,III) oxide ternary composite prepared by (i) adding cerium(III) nitrate hexahydrate and 1,3,5-tris(4-carboxyphenoxy)benzene in a molar ratio of 1:1 into reactor lined with PTFE, adding distilled water, N,N-dimethylformamide and absolute ethanol in a volume ratio of 2:3:2, stirring at room temperature for 30 minutes, sealing it in a stainless steel reaction kettle and reacting at 120 degrees C in a temperature-controlled oven for 72 hours, naturally cooling it to room temperature to obtain colorless massive crystals, washing with distilled water and vacuum drying to obtain (I), (ii) dispersing (I) and graphene oxide in 3 ml and 10 ml of ethanol at a mass ratio of 1-9:1, respectively, ultrasonic treating for 15 minutes, adding graphene oxide dispersion into the cerium complex dispersion, refluxing for 4 hours, reacting and drying to obtain cerium complex/graphene oxide binary complex, and (iii) dispersing the cerium complex/graphene oxide binary complex and iron(II,III) oxide powder in a mass ratio of 5:6 in 1 ml ethanol, ultrasonic treating for 1 hours, centrifuging at 5000 revolutions/minute for 15 minutes, collecting the solid to obtain final product; and (2) preparing magnetic recoverable cerium complex/graphene oxide/iron(II,III) oxide ternary composite as same above method; and (3) treating methylene blue dye wastewater solution, comprising adding 3 mg/20 ml magnetic recoverable cerium complex/graphene oxide/iron(II,III) oxide ternary composite into methylene blue dye wastewater solution having initial concentration of 10 mg/l, and stirring for 30min under dark conditions, performing sunlight irradiation, adding hydrogen peroxide, continuously stirring under the pH of 3-9 at 30-50 degrees C for 120 minutes to make ternary composite fully photocatalytically degrade methylene blue, and separating the ternary composite by setting an external magnetic field.