▎ 摘　　要

NOVELTY - A bacteriostatic agent combination comprises long-chain alkyl betaines doped graphene quantum dots and natural plant extracts comprising two or more of amyglin essential oil, peony bark essential oil and Eucalyptus essential oil in mass ratio (1:8)-(1:1). USE - Bacteriostatic agent combination used in antibacterial washing liquid used in laundry applications (claimed). ADVANTAGE - The bacteriostatic agent combination is green, highly effective and environmentally-friendly. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation of bacteriostatic agent combination which involves dissolving citric acid in double distilled water, adding aqueous ammonia, mixing uniformly, transferring the mixture to a PTFE-lined autoclave, heat preserving the reaction at 100-200 degrees C for 4-8 hours, cooling to room temperature, filtering to remove insoluble debris, dialyzing clear liquid, freeze-drying to obtain a solid powder which is an amino functionalized graphene quantum dot, activating long-chain alkyl betaine in 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide in 2-(N-morpholine)ethanesulfonic acid buffer, where the concentration of 2-(N-morpholine) ethanesulfonic acid buffer is 0.1 mol.L-1, and the pH is 6, adding a phosphate buffer solution of an amino functionalized graphene quantum dot to the mixed solution to obtain long-chain alkyl betaine doped graphene quantum dot, dialyzing, freeze-drying, preparing the long-chain alkyl betaine doped graphene quantum dots and the natural plant extract in a mass ratio of (1:8)-(1:1) to obtain a composite. The long-chain alkyl betaine is an N-long-chain alkyl carboxylic acid type betaine of formula: CH3(CH2)nN+(CH3)2CH2COO-, where n is 11-17; and (2) bacteriostatic washing liquid which comprises 0-35 %mass alkyl glucoside, 0-20 %mass amino acid surfactant, 0-10 %mass amphoteric surfactant, 0-3 %mass chelating agent, 0-3 %mass anti-redeposition agent, 0-3 %mass thickener, 0-2 %mass compound biological enzyme, citric acid to adjust pH to 5.5-7, 0.5-2 %mass bacteriostatic agent combination and balance water.