▎ 摘　　要

NOVELTY - Preparing graphene quantum dots/cerium-2-methyl imidazole (GQDs/Ce-2MI) photocatalytic bactericide, comprises (i) hydrothermally reacting starch suspension to obtain graphene quantum dots (GQDs) solution, (ii) dispersing the cerium salt and the GQDs solution in water to obtain solution A, dispersing 2-methylimidazole and the GQDs solution in water to obtain solution B, and mixing the solution A and solution B to obtain GQDs/Ce-2MI precursor solution, and (iii) successively allowing the GQDs/Ce-2MI precursor solution to stand, washing, vacuum-drying, and grinding to obtain a GQDs/Ce-2MI composite photocatalyst. USE - The bactericide is useful for processing wastewater containing Escherichia coli (all claimed). ADVANTAGE - The method: is controllable; and prepares product which has high visible light responsiveness, excellent photocatalytic sterilization activity, and excellent wastewater treatment effect. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) graphene quantum dots/cerium-2-methyl imidazole (GQDs/Ce-2MI) photocatalytic bactericide prepared by the above-mentioned method; and (2) processing wastewater containing Escherichia coli, comprising adding the GQDs Ce-2MI composite photocatalytic bactericide into the to-be-processed containing E. coli waste water, stirring to absorb balance in dark place opening the visible light source, and performing photocatalytic sterilization.